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[tomato.git] / release / src-rt-6.x.4708 / linux / linux-2.6.36 / drivers / scsi / NCR5380.c

/* 
 * NCR 5380 generic driver routines.  These should make it *trivial*
 *      to implement 5380 SCSI drivers under Linux with a non-trantor
 *      architecture.
 *
 *      Note that these routines also work with NR53c400 family chips.
 *
 * Copyright 1993, Drew Eckhardt
 *      Visionary Computing 
 *      (Unix and Linux consulting and custom programming)
 *      drew@colorado.edu
 *      +1 (303) 666-5836
 *
 * DISTRIBUTION RELEASE 6. 
 *
 * For more information, please consult 
 *
 * NCR 5380 Family
 * SCSI Protocol Controller
 * Databook
 *
 * NCR Microelectronics
 * 1635 Aeroplaza Drive
 * Colorado Springs, CO 80916
 * 1+ (719) 578-3400
 * 1+ (800) 334-5454
 */

/*
 * $Log: NCR5380.c,v $

 * Revision 1.10 1998/9/2       Alan Cox
 *                              (alan@lxorguk.ukuu.org.uk)
 * Fixed up the timer lockups reported so far. Things still suck. Looking 
 * forward to 2.3 and per device request queues. Then it'll be possible to
 * SMP thread this beast and improve life no end.
 
 * Revision 1.9  1997/7/27      Ronald van Cuijlenborg
 *                              (ronald.van.cuijlenborg@tip.nl or nutty@dds.nl)
 * (hopefully) fixed and enhanced USLEEP
 * added support for DTC3181E card (for Mustek scanner)
 *

 * Revision 1.8                 Ingmar Baumgart
 *                              (ingmar@gonzo.schwaben.de)
 * added support for NCR53C400a card
 *

 * Revision 1.7  1996/3/2       Ray Van Tassle (rayvt@comm.mot.com)
 * added proc_info
 * added support needed for DTC 3180/3280
 * fixed a couple of bugs
 *

 * Revision 1.5  1994/01/19  09:14:57  drew
 * Fixed udelay() hack that was being used on DATAOUT phases
 * instead of a proper wait for the final handshake.
 *
 * Revision 1.4  1994/01/19  06:44:25  drew
 * *** empty log message ***
 *
 * Revision 1.3  1994/01/19  05:24:40  drew
 * Added support for TCR LAST_BYTE_SENT bit.
 *
 * Revision 1.2  1994/01/15  06:14:11  drew
 * REAL DMA support, bug fixes.
 *
 * Revision 1.1  1994/01/15  06:00:54  drew
 * Initial revision
 *
 */

/*
 * Further development / testing that should be done : 
 * 1.  Cleanup the NCR5380_transfer_dma function and DMA operation complete
 *     code so that everything does the same thing that's done at the 
 *     end of a pseudo-DMA read operation.
 *
 * 2.  Fix REAL_DMA (interrupt driven, polled works fine) -
 *     basically, transfer size needs to be reduced by one 
 *     and the last byte read as is done with PSEUDO_DMA.
 * 
 * 4.  Test SCSI-II tagged queueing (I have no devices which support 
 *      tagged queueing)
 *
 * 5.  Test linked command handling code after Eric is ready with 
 *      the high level code.
 */
#include <scsi/scsi_dbg.h>
#include <scsi/scsi_transport_spi.h>

#ifndef NDEBUG
#define NDEBUG 0
#endif
#ifndef NDEBUG_ABORT
#define NDEBUG_ABORT 0
#endif

#if (NDEBUG & NDEBUG_LISTS)
#define LIST(x,y) {printk("LINE:%d   Adding %p to %p\n", __LINE__, (void*)(x), (void*)(y)); if ((x)==(y)) udelay(5); }
#define REMOVE(w,x,y,z) {printk("LINE:%d   Removing: %p->%p  %p->%p \n", __LINE__, (void*)(w), (void*)(x), (void*)(y), (void*)(z)); if ((x)==(y)) udelay(5); }
#else
#define LIST(x,y)
#define REMOVE(w,x,y,z)
#endif

#ifndef notyet
#undef LINKED
#undef REAL_DMA
#endif

#ifdef REAL_DMA_POLL
#undef READ_OVERRUNS
#define READ_OVERRUNS
#endif

#ifdef BOARD_REQUIRES_NO_DELAY
#define io_recovery_delay(x)
#else
#define io_recovery_delay(x)    udelay(x)
#endif


/*
 * Using this file :
 * This file a skeleton Linux SCSI driver for the NCR 5380 series
 * of chips.  To use it, you write an architecture specific functions 
 * and macros and include this file in your driver.
 *
 * These macros control options : 
 * AUTOPROBE_IRQ - if defined, the NCR5380_probe_irq() function will be 
 *      defined.
 * 
 * AUTOSENSE - if defined, REQUEST SENSE will be performed automatically
 *      for commands that return with a CHECK CONDITION status. 
 *
 * DIFFERENTIAL - if defined, NCR53c81 chips will use external differential
 *      transceivers. 
 *
 * DONT_USE_INTR - if defined, never use interrupts, even if we probe or
 *      override-configure an IRQ.
 *
 * LIMIT_TRANSFERSIZE - if defined, limit the pseudo-dma transfers to 512
 *      bytes at a time.  Since interrupts are disabled by default during
 *      these transfers, we might need this to give reasonable interrupt
 *      service time if the transfer size gets too large.
 *
 * LINKED - if defined, linked commands are supported.
 *
 * PSEUDO_DMA - if defined, PSEUDO DMA is used during the data transfer phases.
 *
 * REAL_DMA - if defined, REAL DMA is used during the data transfer phases.
 *
 * REAL_DMA_POLL - if defined, REAL DMA is used but the driver doesn't
 *      rely on phase mismatch and EOP interrupts to determine end 
 *      of phase.
 *
 * UNSAFE - leave interrupts enabled during pseudo-DMA transfers.  You
 *          only really want to use this if you're having a problem with
 *          dropped characters during high speed communications, and even
 *          then, you're going to be better off twiddling with transfersize
 *          in the high level code.
 *
 * Defaults for these will be provided although the user may want to adjust 
 * these to allocate CPU resources to the SCSI driver or "real" code.
 * 
 * USLEEP_SLEEP - amount of time, in jiffies, to sleep
 *
 * USLEEP_POLL - amount of time, in jiffies, to poll
 *
 * These macros MUST be defined :
 * NCR5380_local_declare() - declare any local variables needed for your
 *      transfer routines.
 *
 * NCR5380_setup(instance) - initialize any local variables needed from a given
 *      instance of the host adapter for NCR5380_{read,write,pread,pwrite}
 * 
 * NCR5380_read(register)  - read from the specified register
 *
 * NCR5380_write(register, value) - write to the specific register 
 *
 * NCR5380_implementation_fields  - additional fields needed for this 
 *      specific implementation of the NCR5380
 *
 * Either real DMA *or* pseudo DMA may be implemented
 * REAL functions : 
 * NCR5380_REAL_DMA should be defined if real DMA is to be used.
 * Note that the DMA setup functions should return the number of bytes 
 *      that they were able to program the controller for.
 *
 * Also note that generic i386/PC versions of these macros are 
 *      available as NCR5380_i386_dma_write_setup,
 *      NCR5380_i386_dma_read_setup, and NCR5380_i386_dma_residual.
 *
 * NCR5380_dma_write_setup(instance, src, count) - initialize
 * NCR5380_dma_read_setup(instance, dst, count) - initialize
 * NCR5380_dma_residual(instance); - residual count
 *
 * PSEUDO functions :
 * NCR5380_pwrite(instance, src, count)
 * NCR5380_pread(instance, dst, count);
 *
 * The generic driver is initialized by calling NCR5380_init(instance),
 * after setting the appropriate host specific fields and ID.  If the 
 * driver wishes to autoprobe for an IRQ line, the NCR5380_probe_irq(instance,
 * possible) function may be used.
 */

static int do_abort(struct Scsi_Host *host);
static void do_reset(struct Scsi_Host *host);

/*
 *      initialize_SCp          -       init the scsi pointer field
 *      @cmd: command block to set up
 *
 *      Set up the internal fields in the SCSI command.
 */

static __inline__ void initialize_SCp(Scsi_Cmnd * cmd)
{
        /* 
         * Initialize the Scsi Pointer field so that all of the commands in the 
         * various queues are valid.
         */

        if (scsi_bufflen(cmd)) {
                cmd->SCp.buffer = scsi_sglist(cmd);
                cmd->SCp.buffers_residual = scsi_sg_count(cmd) - 1;
                cmd->SCp.ptr = sg_virt(cmd->SCp.buffer);
                cmd->SCp.this_residual = cmd->SCp.buffer->length;
        } else {
                cmd->SCp.buffer = NULL;
                cmd->SCp.buffers_residual = 0;
                cmd->SCp.ptr = NULL;
                cmd->SCp.this_residual = 0;
        }
}

/**
 *      NCR5380_poll_politely   -       wait for NCR5380 status bits
 *      @instance: controller to poll
 *      @reg: 5380 register to poll
 *      @bit: Bitmask to check
 *      @val: Value required to exit
 *
 *      Polls the NCR5380 in a reasonably efficient manner waiting for
 *      an event to occur, after a short quick poll we begin giving the
 *      CPU back in non IRQ contexts
 *
 *      Returns the value of the register or a negative error code.
 */
 
static int NCR5380_poll_politely(struct Scsi_Host *instance, int reg, int bit, int val, int t)
{
        NCR5380_local_declare();
        int n = 500;            /* At about 8uS a cycle for the cpu access */
        unsigned long end = jiffies + t;
        int r;
        
        NCR5380_setup(instance);

        while( n-- > 0)
        {
                r = NCR5380_read(reg);
                if((r & bit) == val)
                        return 0;
                cpu_relax();
        }
        
        /* t time yet ? */
        while(time_before(jiffies, end))
        {
                r = NCR5380_read(reg);
                if((r & bit) == val)
                        return 0;
                if(!in_interrupt())
                        cond_resched();
                else
                        cpu_relax();
        }
        return -ETIMEDOUT;
}

static struct {
        unsigned char value;
        const char *name;
} phases[] __maybe_unused = {
        {PHASE_DATAOUT, "DATAOUT"}, 
        {PHASE_DATAIN, "DATAIN"}, 
        {PHASE_CMDOUT, "CMDOUT"}, 
        {PHASE_STATIN, "STATIN"}, 
        {PHASE_MSGOUT, "MSGOUT"}, 
        {PHASE_MSGIN, "MSGIN"}, 
        {PHASE_UNKNOWN, "UNKNOWN"}
};

#if NDEBUG
static struct {
        unsigned char mask;
        const char *name;
} signals[] = { 
        {SR_DBP, "PARITY"}, 
        {SR_RST, "RST"}, 
        {SR_BSY, "BSY"}, 
        {SR_REQ, "REQ"}, 
        {SR_MSG, "MSG"}, 
        {SR_CD, "CD"}, 
        {SR_IO, "IO"}, 
        {SR_SEL, "SEL"}, 
        {0, NULL}
}, 
basrs[] = {
        {BASR_ATN, "ATN"}, 
        {BASR_ACK, "ACK"}, 
        {0, NULL}
}, 
icrs[] = { 
        {ICR_ASSERT_RST, "ASSERT RST"}, 
        {ICR_ASSERT_ACK, "ASSERT ACK"}, 
        {ICR_ASSERT_BSY, "ASSERT BSY"}, 
        {ICR_ASSERT_SEL, "ASSERT SEL"}, 
        {ICR_ASSERT_ATN, "ASSERT ATN"}, 
        {ICR_ASSERT_DATA, "ASSERT DATA"}, 
        {0, NULL}
}, 
mrs[] = { 
        {MR_BLOCK_DMA_MODE, "MODE BLOCK DMA"}, 
        {MR_TARGET, "MODE TARGET"}, 
        {MR_ENABLE_PAR_CHECK, "MODE PARITY CHECK"}, 
        {MR_ENABLE_PAR_INTR, "MODE PARITY INTR"}, 
        {MR_MONITOR_BSY, "MODE MONITOR BSY"}, 
        {MR_DMA_MODE, "MODE DMA"}, 
        {MR_ARBITRATE, "MODE ARBITRATION"}, 
        {0, NULL}
};

/**
 *      NCR5380_print   -       print scsi bus signals
 *      @instance:      adapter state to dump
 *
 *      Print the SCSI bus signals for debugging purposes
 *
 *      Locks: caller holds hostdata lock (not essential)
 */

static void NCR5380_print(struct Scsi_Host *instance)
{
        NCR5380_local_declare();
        unsigned char status, data, basr, mr, icr, i;
        NCR5380_setup(instance);

        data = NCR5380_read(CURRENT_SCSI_DATA_REG);
        status = NCR5380_read(STATUS_REG);
        mr = NCR5380_read(MODE_REG);
        icr = NCR5380_read(INITIATOR_COMMAND_REG);
        basr = NCR5380_read(BUS_AND_STATUS_REG);

        printk("STATUS_REG: %02x ", status);
        for (i = 0; signals[i].mask; ++i)
                if (status & signals[i].mask)
                        printk(",%s", signals[i].name);
        printk("\nBASR: %02x ", basr);
        for (i = 0; basrs[i].mask; ++i)
                if (basr & basrs[i].mask)
                        printk(",%s", basrs[i].name);
        printk("\nICR: %02x ", icr);
        for (i = 0; icrs[i].mask; ++i)
                if (icr & icrs[i].mask)
                        printk(",%s", icrs[i].name);
        printk("\nMODE: %02x ", mr);
        for (i = 0; mrs[i].mask; ++i)
                if (mr & mrs[i].mask)
                        printk(",%s", mrs[i].name);
        printk("\n");
}


/* 
 *      NCR5380_print_phase     -       show SCSI phase
 *      @instance: adapter to dump
 *
 *      Print the current SCSI phase for debugging purposes
 *
 *      Locks: none
 */

static void NCR5380_print_phase(struct Scsi_Host *instance)
{
        NCR5380_local_declare();
        unsigned char status;
        int i;
        NCR5380_setup(instance);

        status = NCR5380_read(STATUS_REG);
        if (!(status & SR_REQ))
                printk("scsi%d : REQ not asserted, phase unknown.\n", instance->host_no);
        else {
                for (i = 0; (phases[i].value != PHASE_UNKNOWN) && (phases[i].value != (status & PHASE_MASK)); ++i);
                printk("scsi%d : phase %s\n", instance->host_no, phases[i].name);
        }
}
#endif

/*
 * These need tweaking, and would probably work best as per-device 
 * flags initialized differently for disk, tape, cd, etc devices.
 * People with broken devices are free to experiment as to what gives
 * the best results for them.
 *
 * USLEEP_SLEEP should be a minimum seek time.
 *
 * USLEEP_POLL should be a maximum rotational latency.
 */
#ifndef USLEEP_SLEEP
/* 20 ms (reasonable hard disk speed) */
#define USLEEP_SLEEP (20*HZ/1000)
#endif
/* 300 RPM (floppy speed) */
#ifndef USLEEP_POLL
#define USLEEP_POLL (200*HZ/1000)
#endif
#ifndef USLEEP_WAITLONG
/* RvC: (reasonable time to wait on select error) */
#define USLEEP_WAITLONG USLEEP_SLEEP
#endif

/* 
 * Function : int should_disconnect (unsigned char cmd)
 *
 * Purpose : decide whether a command would normally disconnect or 
 *      not, since if it won't disconnect we should go to sleep.
 *
 * Input : cmd - opcode of SCSI command
 *
 * Returns : DISCONNECT_LONG if we should disconnect for a really long 
 *      time (ie always, sleep, look for REQ active, sleep), 
 *      DISCONNECT_TIME_TO_DATA if we would only disconnect for a normal
 *      time-to-data delay, DISCONNECT_NONE if this command would return
 *      immediately.
 *
 *      Future sleep algorithms based on time to data can exploit 
 *      something like this so they can differentiate between "normal" 
 *      (ie, read, write, seek) and unusual commands (ie, * format).
 *
 * Note : We don't deal with commands that handle an immediate disconnect,
 *        
 */

static int should_disconnect(unsigned char cmd)
{
        switch (cmd) {
        case READ_6:
        case WRITE_6:
        case SEEK_6:
        case READ_10:
        case WRITE_10:
        case SEEK_10:
                return DISCONNECT_TIME_TO_DATA;
        case FORMAT_UNIT:
        case SEARCH_HIGH:
        case SEARCH_LOW:
        case SEARCH_EQUAL:
                return DISCONNECT_LONG;
        default:
                return DISCONNECT_NONE;
        }
}

static void NCR5380_set_timer(struct NCR5380_hostdata *hostdata, unsigned long timeout)
{
        hostdata->time_expires = jiffies + timeout;
        schedule_delayed_work(&hostdata->coroutine, timeout);
}


static int probe_irq __initdata = 0;

/**
 *      probe_intr      -       helper for IRQ autoprobe
 *      @irq: interrupt number
 *      @dev_id: unused
 *      @regs: unused
 *
 *      Set a flag to indicate the IRQ in question was received. This is
 *      used by the IRQ probe code.
 */
 
static irqreturn_t __init probe_intr(int irq, void *dev_id)
{
        probe_irq = irq;
        return IRQ_HANDLED;
}

/**
 *      NCR5380_probe_irq       -       find the IRQ of an NCR5380
 *      @instance: NCR5380 controller
 *      @possible: bitmask of ISA IRQ lines
 *
 *      Autoprobe for the IRQ line used by the NCR5380 by triggering an IRQ
 *      and then looking to see what interrupt actually turned up.
 *
 *      Locks: none, irqs must be enabled on entry
 */

static int __init __maybe_unused NCR5380_probe_irq(struct Scsi_Host *instance,
                                                int possible)
{
        NCR5380_local_declare();
        struct NCR5380_hostdata *hostdata = (struct NCR5380_hostdata *) instance->hostdata;
        unsigned long timeout;
        int trying_irqs, i, mask;
        NCR5380_setup(instance);

        for (trying_irqs = i = 0, mask = 1; i < 16; ++i, mask <<= 1)
                if ((mask & possible) && (request_irq(i, &probe_intr, IRQF_DISABLED, "NCR-probe", NULL) == 0))
                        trying_irqs |= mask;

        timeout = jiffies + (250 * HZ / 1000);
        probe_irq = SCSI_IRQ_NONE;

        /*
         * A interrupt is triggered whenever BSY = false, SEL = true
         * and a bit set in the SELECT_ENABLE_REG is asserted on the 
         * SCSI bus.
         *
         * Note that the bus is only driven when the phase control signals
         * (I/O, C/D, and MSG) match those in the TCR, so we must reset that
         * to zero.
         */

        NCR5380_write(TARGET_COMMAND_REG, 0);
        NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
        NCR5380_write(OUTPUT_DATA_REG, hostdata->id_mask);
        NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_DATA | ICR_ASSERT_SEL);

        while (probe_irq == SCSI_IRQ_NONE && time_before(jiffies, timeout))
                schedule_timeout_uninterruptible(1);
        
        NCR5380_write(SELECT_ENABLE_REG, 0);
        NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);

        for (i = 0, mask = 1; i < 16; ++i, mask <<= 1)
                if (trying_irqs & mask)
                        free_irq(i, NULL);

        return probe_irq;
}

/**
 *      NCR58380_print_options  -       show options
 *      @instance: unused for now
 *
 *      Called by probe code indicating the NCR5380 driver options that 
 *      were selected. At some point this will switch to runtime options
 *      read from the adapter in question
 *
 *      Locks: none
 */

static void __init __maybe_unused
NCR5380_print_options(struct Scsi_Host *instance)
{
        printk(" generic options"
#ifdef AUTOPROBE_IRQ
               " AUTOPROBE_IRQ"
#endif
#ifdef AUTOSENSE
               " AUTOSENSE"
#endif
#ifdef DIFFERENTIAL
               " DIFFERENTIAL"
#endif
#ifdef REAL_DMA
               " REAL DMA"
#endif
#ifdef REAL_DMA_POLL
               " REAL DMA POLL"
#endif
#ifdef PARITY
               " PARITY"
#endif
#ifdef PSEUDO_DMA
               " PSEUDO DMA"
#endif
#ifdef UNSAFE
               " UNSAFE "
#endif
            );
        printk(" USLEEP, USLEEP_POLL=%d USLEEP_SLEEP=%d", USLEEP_POLL, USLEEP_SLEEP);
        printk(" generic release=%d", NCR5380_PUBLIC_RELEASE);
        if (((struct NCR5380_hostdata *) instance->hostdata)->flags & FLAG_NCR53C400) {
                printk(" ncr53c400 release=%d", NCR53C400_PUBLIC_RELEASE);
        }
}

/**
 *      NCR5380_print_status    -       dump controller info
 *      @instance: controller to dump
 *
 *      Print commands in the various queues, called from NCR5380_abort 
 *      and NCR5380_debug to aid debugging.
 *
 *      Locks: called functions disable irqs
 */

static void NCR5380_print_status(struct Scsi_Host *instance)
{
        NCR5380_dprint(NDEBUG_ANY, instance);
        NCR5380_dprint_phase(NDEBUG_ANY, instance);
}

/******************************************/
/*
 * /proc/scsi/[dtc pas16 t128 generic]/[0-ASC_NUM_BOARD_SUPPORTED]
 *
 * *buffer: I/O buffer
 * **start: if inout == FALSE pointer into buffer where user read should start
 * offset: current offset
 * length: length of buffer
 * hostno: Scsi_Host host_no
 * inout: TRUE - user is writing; FALSE - user is reading
 *
 * Return the number of bytes read from or written
 */

#undef SPRINTF
#define SPRINTF(args...) do { if(pos < buffer + length-80) pos += sprintf(pos, ## args); } while(0)
static
char *lprint_Scsi_Cmnd(Scsi_Cmnd * cmd, char *pos, char *buffer, int length);
static
char *lprint_command(unsigned char *cmd, char *pos, char *buffer, int len);
static
char *lprint_opcode(int opcode, char *pos, char *buffer, int length);

static int __maybe_unused NCR5380_proc_info(struct Scsi_Host *instance,
        char *buffer, char **start, off_t offset, int length, int inout)
{
        char *pos = buffer;
        struct NCR5380_hostdata *hostdata;
        Scsi_Cmnd *ptr;

        hostdata = (struct NCR5380_hostdata *) instance->hostdata;

        if (inout) {            /* Has data been written to the file ? */
#ifdef DTC_PUBLIC_RELEASE
                dtc_wmaxi = dtc_maxi = 0;
#endif
#ifdef PAS16_PUBLIC_RELEASE
                pas_wmaxi = pas_maxi = 0;
#endif
                return (-ENOSYS);       /* Currently this is a no-op */
        }
        SPRINTF("NCR5380 core release=%d.   ", NCR5380_PUBLIC_RELEASE);
        if (((struct NCR5380_hostdata *) instance->hostdata)->flags & FLAG_NCR53C400)
                SPRINTF("ncr53c400 release=%d.  ", NCR53C400_PUBLIC_RELEASE);
#ifdef DTC_PUBLIC_RELEASE
        SPRINTF("DTC 3180/3280 release %d", DTC_PUBLIC_RELEASE);
#endif
#ifdef T128_PUBLIC_RELEASE
        SPRINTF("T128 release %d", T128_PUBLIC_RELEASE);
#endif
#ifdef GENERIC_NCR5380_PUBLIC_RELEASE
        SPRINTF("Generic5380 release %d", GENERIC_NCR5380_PUBLIC_RELEASE);
#endif
#ifdef PAS16_PUBLIC_RELEASE
        SPRINTF("PAS16 release=%d", PAS16_PUBLIC_RELEASE);
#endif

        SPRINTF("\nBase Addr: 0x%05lX    ", (long) instance->base);
        SPRINTF("io_port: %04x      ", (int) instance->io_port);
        if (instance->irq == SCSI_IRQ_NONE)
                SPRINTF("IRQ: None.\n");
        else
                SPRINTF("IRQ: %d.\n", instance->irq);

#ifdef DTC_PUBLIC_RELEASE
        SPRINTF("Highwater I/O busy_spin_counts -- write: %d  read: %d\n", dtc_wmaxi, dtc_maxi);
#endif
#ifdef PAS16_PUBLIC_RELEASE
        SPRINTF("Highwater I/O busy_spin_counts -- write: %d  read: %d\n", pas_wmaxi, pas_maxi);
#endif
        spin_lock_irq(instance->host_lock);
        if (!hostdata->connected)
                SPRINTF("scsi%d: no currently connected command\n", instance->host_no);
        else
                pos = lprint_Scsi_Cmnd((Scsi_Cmnd *) hostdata->connected, pos, buffer, length);
        SPRINTF("scsi%d: issue_queue\n", instance->host_no);
        for (ptr = (Scsi_Cmnd *) hostdata->issue_queue; ptr; ptr = (Scsi_Cmnd *) ptr->host_scribble)
                pos = lprint_Scsi_Cmnd(ptr, pos, buffer, length);

        SPRINTF("scsi%d: disconnected_queue\n", instance->host_no);
        for (ptr = (Scsi_Cmnd *) hostdata->disconnected_queue; ptr; ptr = (Scsi_Cmnd *) ptr->host_scribble)
                pos = lprint_Scsi_Cmnd(ptr, pos, buffer, length);
        spin_unlock_irq(instance->host_lock);
        
        *start = buffer;
        if (pos - buffer < offset)
                return 0;
        else if (pos - buffer - offset < length)
                return pos - buffer - offset;
        return length;
}

static char *lprint_Scsi_Cmnd(Scsi_Cmnd * cmd, char *pos, char *buffer, int length)
{
        SPRINTF("scsi%d : destination target %d, lun %d\n", cmd->device->host->host_no, cmd->device->id, cmd->device->lun);
        SPRINTF("        command = ");
        pos = lprint_command(cmd->cmnd, pos, buffer, length);
        return (pos);
}

static char *lprint_command(unsigned char *command, char *pos, char *buffer, int length)
{
        int i, s;
        pos = lprint_opcode(command[0], pos, buffer, length);
        for (i = 1, s = COMMAND_SIZE(command[0]); i < s; ++i)
                SPRINTF("%02x ", command[i]);
        SPRINTF("\n");
        return (pos);
}

static char *lprint_opcode(int opcode, char *pos, char *buffer, int length)
{
        SPRINTF("%2d (0x%02x)", opcode, opcode);
        return (pos);
}


/**
 *      NCR5380_init    -       initialise an NCR5380
 *      @instance: adapter to configure
 *      @flags: control flags
 *
 *      Initializes *instance and corresponding 5380 chip,
 *      with flags OR'd into the initial flags value.
 *
 *      Notes : I assume that the host, hostno, and id bits have been
 *      set correctly.  I don't care about the irq and other fields. 
 *
 *      Returns 0 for success
 *
 *      Locks: interrupts must be enabled when we are called 
 */

static int __devinit NCR5380_init(struct Scsi_Host *instance, int flags)
{
        NCR5380_local_declare();
        int i, pass;
        unsigned long timeout;
        struct NCR5380_hostdata *hostdata = (struct NCR5380_hostdata *) instance->hostdata;

        if(in_interrupt())
                printk(KERN_ERR "NCR5380_init called with interrupts off!\n");
        /* 
         * On NCR53C400 boards, NCR5380 registers are mapped 8 past 
         * the base address.
         */

#ifdef NCR53C400
        if (flags & FLAG_NCR53C400)
                instance->NCR5380_instance_name += NCR53C400_address_adjust;
#endif

        NCR5380_setup(instance);

        hostdata->aborted = 0;
        hostdata->id_mask = 1 << instance->this_id;
        for (i = hostdata->id_mask; i <= 0x80; i <<= 1)
                if (i > hostdata->id_mask)
                        hostdata->id_higher_mask |= i;
        for (i = 0; i < 8; ++i)
                hostdata->busy[i] = 0;
#ifdef REAL_DMA
        hostdata->dmalen = 0;
#endif
        hostdata->targets_present = 0;
        hostdata->connected = NULL;
        hostdata->issue_queue = NULL;
        hostdata->disconnected_queue = NULL;
        
        INIT_DELAYED_WORK(&hostdata->coroutine, NCR5380_main);
        
#ifdef NCR5380_STATS
        for (i = 0; i < 8; ++i) {
                hostdata->time_read[i] = 0;
                hostdata->time_write[i] = 0;
                hostdata->bytes_read[i] = 0;
                hostdata->bytes_write[i] = 0;
        }
        hostdata->timebase = 0;
        hostdata->pendingw = 0;
        hostdata->pendingr = 0;
#endif

        /* The CHECK code seems to break the 53C400. Will check it later maybe */
        if (flags & FLAG_NCR53C400)
                hostdata->flags = FLAG_HAS_LAST_BYTE_SENT | flags;
        else
                hostdata->flags = FLAG_CHECK_LAST_BYTE_SENT | flags;

        hostdata->host = instance;
        hostdata->time_expires = 0;

#ifndef AUTOSENSE
        if ((instance->cmd_per_lun > 1) || instance->can_queue > 1)
                    printk(KERN_WARNING "scsi%d : WARNING : support for multiple outstanding commands enabled\n" "         without AUTOSENSE option, contingent allegiance conditions may\n"
                           "         be incorrectly cleared.\n", instance->host_no);
#endif                          /* def AUTOSENSE */

        NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
        NCR5380_write(MODE_REG, MR_BASE);
        NCR5380_write(TARGET_COMMAND_REG, 0);
        NCR5380_write(SELECT_ENABLE_REG, 0);

#ifdef NCR53C400
        if (hostdata->flags & FLAG_NCR53C400) {
                NCR5380_write(C400_CONTROL_STATUS_REG, CSR_BASE);
        }
#endif

        /* 
         * Detect and correct bus wedge problems.
         *
         * If the system crashed, it may have crashed in a state 
         * where a SCSI command was still executing, and the 
         * SCSI bus is not in a BUS FREE STATE.
         *
         * If this is the case, we'll try to abort the currently
         * established nexus which we know nothing about, and that
         * failing, do a hard reset of the SCSI bus 
         */

        for (pass = 1; (NCR5380_read(STATUS_REG) & SR_BSY) && pass <= 6; ++pass) {
                switch (pass) {
                case 1:
                case 3:
                case 5:
                        printk(KERN_INFO "scsi%d: SCSI bus busy, waiting up to five seconds\n", instance->host_no);
                        timeout = jiffies + 5 * HZ;
                        NCR5380_poll_politely(instance, STATUS_REG, SR_BSY, 0, 5*HZ);
                        break;
                case 2:
                        printk(KERN_WARNING "scsi%d: bus busy, attempting abort\n", instance->host_no);
                        do_abort(instance);
                        break;
                case 4:
                        printk(KERN_WARNING "scsi%d: bus busy, attempting reset\n", instance->host_no);
                        do_reset(instance);
                        break;
                case 6:
                        printk(KERN_ERR "scsi%d: bus locked solid or invalid override\n", instance->host_no);
                        return -ENXIO;
                }
        }
        return 0;
}

/**
 *      NCR5380_exit    -       remove an NCR5380
 *      @instance: adapter to remove
 */

static void NCR5380_exit(struct Scsi_Host *instance)
{
        struct NCR5380_hostdata *hostdata = (struct NCR5380_hostdata *) instance->hostdata;

        cancel_delayed_work(&hostdata->coroutine);
        flush_scheduled_work();
}

/**
 *      NCR5380_queue_command           -       queue a command
 *      @cmd: SCSI command
 *      @done: completion handler
 *
 *      cmd is added to the per instance issue_queue, with minor 
 *      twiddling done to the host specific fields of cmd.  If the 
 *      main coroutine is not running, it is restarted.
 *
 *      Locks: host lock taken by caller
 */

static int NCR5380_queue_command(Scsi_Cmnd * cmd, void (*done) (Scsi_Cmnd *)) 
{
        struct Scsi_Host *instance = cmd->device->host;
        struct NCR5380_hostdata *hostdata = (struct NCR5380_hostdata *) instance->hostdata;
        Scsi_Cmnd *tmp;

#if (NDEBUG & NDEBUG_NO_WRITE)
        switch (cmd->cmnd[0]) {
        case WRITE_6:
        case WRITE_10:
                printk("scsi%d : WRITE attempted with NO_WRITE debugging flag set\n", instance->host_no);
                cmd->result = (DID_ERROR << 16);
                done(cmd);
                return 0;
        }
#endif                          /* (NDEBUG & NDEBUG_NO_WRITE) */

#ifdef NCR5380_STATS
        switch (cmd->cmnd[0]) {
                case WRITE:
                case WRITE_6:
                case WRITE_10:
                        hostdata->time_write[cmd->device->id] -= (jiffies - hostdata->timebase);
                        hostdata->bytes_write[cmd->device->id] += scsi_bufflen(cmd);
                        hostdata->pendingw++;
                        break;
                case READ:
                case READ_6:
                case READ_10:
                        hostdata->time_read[cmd->device->id] -= (jiffies - hostdata->timebase);
                        hostdata->bytes_read[cmd->device->id] += scsi_bufflen(cmd);
                        hostdata->pendingr++;
                        break;
        }
#endif

        /* 
         * We use the host_scribble field as a pointer to the next command  
         * in a queue 
         */

        cmd->host_scribble = NULL;
        cmd->scsi_done = done;
        cmd->result = 0;

        /* 
         * Insert the cmd into the issue queue. Note that REQUEST SENSE 
         * commands are added to the head of the queue since any command will
         * clear the contingent allegiance condition that exists and the 
         * sense data is only guaranteed to be valid while the condition exists.
         */

        if (!(hostdata->issue_queue) || (cmd->cmnd[0] == REQUEST_SENSE)) {
                LIST(cmd, hostdata->issue_queue);
                cmd->host_scribble = (unsigned char *) hostdata->issue_queue;
                hostdata->issue_queue = cmd;
        } else {
                for (tmp = (Scsi_Cmnd *) hostdata->issue_queue; tmp->host_scribble; tmp = (Scsi_Cmnd *) tmp->host_scribble);
                LIST(cmd, tmp);
                tmp->host_scribble = (unsigned char *) cmd;
        }
        dprintk(NDEBUG_QUEUES, ("scsi%d : command added to %s of queue\n", instance->host_no, (cmd->cmnd[0] == REQUEST_SENSE) ? "head" : "tail"));

        /* Run the coroutine if it isn't already running. */
        /* Kick off command processing */
        schedule_delayed_work(&hostdata->coroutine, 0);
        return 0;
}


/**
 *      NCR5380_main    -       NCR state machines
 *
 *      NCR5380_main is a coroutine that runs as long as more work can 
 *      be done on the NCR5380 host adapters in a system.  Both 
 *      NCR5380_queue_command() and NCR5380_intr() will try to start it 
 *      in case it is not running.
 * 
 *      Locks: called as its own thread with no locks held. Takes the
 *      host lock and called routines may take the isa dma lock.
 */

static void NCR5380_main(struct work_struct *work)
{
        struct NCR5380_hostdata *hostdata =
                container_of(work, struct NCR5380_hostdata, coroutine.work);
        struct Scsi_Host *instance = hostdata->host;
        Scsi_Cmnd *tmp, *prev;
        int done;
        
        spin_lock_irq(instance->host_lock);
        do {
                /* Lock held here */
                done = 1;
                if (!hostdata->connected && !hostdata->selecting) {
                        dprintk(NDEBUG_MAIN, ("scsi%d : not connected\n", instance->host_no));
                        /*
                         * Search through the issue_queue for a command destined
                         * for a target that's not busy.
                         */
                        for (tmp = (Scsi_Cmnd *) hostdata->issue_queue, prev = NULL; tmp; prev = tmp, tmp = (Scsi_Cmnd *) tmp->host_scribble) 
                        {
                                if (prev != tmp)
                                        dprintk(NDEBUG_LISTS, ("MAIN tmp=%p   target=%d   busy=%d lun=%d\n", tmp, tmp->target, hostdata->busy[tmp->target], tmp->lun));
                                /*  When we find one, remove it from the issue queue. */
                                if (!(hostdata->busy[tmp->device->id] & (1 << tmp->device->lun))) {
                                        if (prev) {
                                                REMOVE(prev, prev->host_scribble, tmp, tmp->host_scribble);
                                                prev->host_scribble = tmp->host_scribble;
                                        } else {
                                                REMOVE(-1, hostdata->issue_queue, tmp, tmp->host_scribble);
                                                hostdata->issue_queue = (Scsi_Cmnd *) tmp->host_scribble;
                                        }
                                        tmp->host_scribble = NULL;

                                        /* 
                                         * Attempt to establish an I_T_L nexus here. 
                                         * On success, instance->hostdata->connected is set.
                                         * On failure, we must add the command back to the
                                         *   issue queue so we can keep trying. 
                                         */
                                        dprintk(NDEBUG_MAIN|NDEBUG_QUEUES, ("scsi%d : main() : command for target %d lun %d removed from issue_queue\n", instance->host_no, tmp->target, tmp->lun));
        
                                        /*
                                         * A successful selection is defined as one that 
                                         * leaves us with the command connected and 
                                         * in hostdata->connected, OR has terminated the
                                         * command.
                                         *
                                         * With successful commands, we fall through
                                         * and see if we can do an information transfer,
                                         * with failures we will restart.
                                         */
                                        hostdata->selecting = NULL;
                                        /* RvC: have to preset this to indicate a new command is being performed */

                                        if (!NCR5380_select(instance, tmp,
                                                            /* 
                                                             * REQUEST SENSE commands are issued without tagged
                                                             * queueing, even on SCSI-II devices because the 
                                                             * contingent allegiance condition exists for the 
                                                             * entire unit.
                                                             */
                                                            (tmp->cmnd[0] == REQUEST_SENSE) ? TAG_NONE : TAG_NEXT)) {
                                                break;
                                        } else {
                                                LIST(tmp, hostdata->issue_queue);
                                                tmp->host_scribble = (unsigned char *) hostdata->issue_queue;
                                                hostdata->issue_queue = tmp;
                                                done = 0;
                                                dprintk(NDEBUG_MAIN|NDEBUG_QUEUES, ("scsi%d : main(): select() failed, returned to issue_queue\n", instance->host_no));
                                        }
                                        /* lock held here still */
                                }       /* if target/lun is not busy */
                        }       /* for */
                        /* exited locked */
                }       /* if (!hostdata->connected) */
                if (hostdata->selecting) {
                        tmp = (Scsi_Cmnd *) hostdata->selecting;
                        /* Selection will drop and retake the lock */
                        if (!NCR5380_select(instance, tmp, (tmp->cmnd[0] == REQUEST_SENSE) ? TAG_NONE : TAG_NEXT)) {
                                /* Ok ?? */
                        } else {
                                /* RvC: device failed, so we wait a long time
                                   this is needed for Mustek scanners, that
                                   do not respond to commands immediately
                                   after a scan */
                                printk(KERN_DEBUG "scsi%d: device %d did not respond in time\n", instance->host_no, tmp->device->id);
                                LIST(tmp, hostdata->issue_queue);
                                tmp->host_scribble = (unsigned char *) hostdata->issue_queue;
                                hostdata->issue_queue = tmp;
                                NCR5380_set_timer(hostdata, USLEEP_WAITLONG);
                        }
                }       /* if hostdata->selecting */
                if (hostdata->connected
#ifdef REAL_DMA
                    && !hostdata->dmalen
#endif
                    && (!hostdata->time_expires || time_before_eq(hostdata->time_expires, jiffies))
                    ) {
                        dprintk(NDEBUG_MAIN, ("scsi%d : main() : performing information transfer\n", instance->host_no));
                        NCR5380_information_transfer(instance);
                        dprintk(NDEBUG_MAIN, ("scsi%d : main() : done set false\n", instance->host_no));
                        done = 0;
                } else
                        break;
        } while (!done);
        
        spin_unlock_irq(instance->host_lock);
}

#ifndef DONT_USE_INTR

/**
 *      NCR5380_intr    -       generic NCR5380 irq handler
 *      @irq: interrupt number
 *      @dev_id: device info
 *
 *      Handle interrupts, reestablishing I_T_L or I_T_L_Q nexuses
 *      from the disconnected queue, and restarting NCR5380_main() 
 *      as required.
 *
 *      Locks: takes the needed instance locks
 */

static irqreturn_t NCR5380_intr(int dummy, void *dev_id)
{
        NCR5380_local_declare();
        struct Scsi_Host *instance = dev_id;
        struct NCR5380_hostdata *hostdata = (struct NCR5380_hostdata *) instance->hostdata;
        int done;
        unsigned char basr;
        unsigned long flags;

        dprintk(NDEBUG_INTR, ("scsi : NCR5380 irq %d triggered\n",
                instance->irq));

        do {
                done = 1;
                spin_lock_irqsave(instance->host_lock, flags);
                /* Look for pending interrupts */
                NCR5380_setup(instance);
                basr = NCR5380_read(BUS_AND_STATUS_REG);
                if (basr & BASR_IRQ) {
                        NCR5380_dprint(NDEBUG_INTR, instance);
                        if ((NCR5380_read(STATUS_REG) & (SR_SEL | SR_IO)) == (SR_SEL | SR_IO)) {
                                done = 0;
                                dprintk(NDEBUG_INTR, ("scsi%d : SEL interrupt\n", instance->host_no));
                                NCR5380_reselect(instance);
                                (void) NCR5380_read(RESET_PARITY_INTERRUPT_REG);
                        } else if (basr & BASR_PARITY_ERROR) {
                                dprintk(NDEBUG_INTR, ("scsi%d : PARITY interrupt\n", instance->host_no));
                                (void) NCR5380_read(RESET_PARITY_INTERRUPT_REG);
                        } else if ((NCR5380_read(STATUS_REG) & SR_RST) == SR_RST) {
                                dprintk(NDEBUG_INTR, ("scsi%d : RESET interrupt\n", instance->host_no));
                                (void) NCR5380_read(RESET_PARITY_INTERRUPT_REG);
                        } else {
#if defined(REAL_DMA)
                                /*
                                 * We should only get PHASE MISMATCH and EOP interrupts
                                 * if we have DMA enabled, so do a sanity check based on
                                 * the current setting of the MODE register.
                                 */

                                if ((NCR5380_read(MODE_REG) & MR_DMA) && ((basr & BASR_END_DMA_TRANSFER) || !(basr & BASR_PHASE_MATCH))) {
                                        int transfered;

                                        if (!hostdata->connected)
                                                panic("scsi%d : received end of DMA interrupt with no connected cmd\n", instance->hostno);

                                        transfered = (hostdata->dmalen - NCR5380_dma_residual(instance));
                                        hostdata->connected->SCp.this_residual -= transferred;
                                        hostdata->connected->SCp.ptr += transferred;
                                        hostdata->dmalen = 0;

                                        (void) NCR5380_read(RESET_PARITY_INTERRUPT_REG);
                                                        
                                        NCR5380_poll_politely(hostdata, BUS_AND_STATUS_REG, BASR_ACK, 0, 2*HZ);

                                        NCR5380_write(MODE_REG, MR_BASE);
                                        NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
                                }
#else
                                dprintk(NDEBUG_INTR, ("scsi : unknown interrupt, BASR 0x%X, MR 0x%X, SR 0x%x\n", basr, NCR5380_read(MODE_REG), NCR5380_read(STATUS_REG)));
                                (void) NCR5380_read(RESET_PARITY_INTERRUPT_REG);
#endif
                        }
                }       /* if BASR_IRQ */
                spin_unlock_irqrestore(instance->host_lock, flags);
                if(!done)
                        schedule_delayed_work(&hostdata->coroutine, 0);
        } while (!done);
        return IRQ_HANDLED;
}

#endif 

/**
 *      collect_stats           -       collect stats on a scsi command
 *      @hostdata: adapter 
 *      @cmd: command being issued
 *
 *      Update the statistical data by parsing the command in question
 */
 
static void collect_stats(struct NCR5380_hostdata *hostdata, Scsi_Cmnd * cmd) 
{
#ifdef NCR5380_STATS
        switch (cmd->cmnd[0]) {
        case WRITE:
        case WRITE_6:
        case WRITE_10:
                hostdata->time_write[scmd_id(cmd)] += (jiffies - hostdata->timebase);
                hostdata->pendingw--;
                break;
        case READ:
        case READ_6:
        case READ_10:
                hostdata->time_read[scmd_id(cmd)] += (jiffies - hostdata->timebase);
                hostdata->pendingr--;
                break;
        }
#endif
}


/* 
 * Function : int NCR5380_select (struct Scsi_Host *instance, Scsi_Cmnd *cmd, 
 *      int tag);
 *
 * Purpose : establishes I_T_L or I_T_L_Q nexus for new or existing command,
 *      including ARBITRATION, SELECTION, and initial message out for 
 *      IDENTIFY and queue messages. 
 *
 * Inputs : instance - instantiation of the 5380 driver on which this 
 *      target lives, cmd - SCSI command to execute, tag - set to TAG_NEXT for 
 *      new tag, TAG_NONE for untagged queueing, otherwise set to the tag for 
 *      the command that is presently connected.
 * 
 * Returns : -1 if selection could not execute for some reason,
 *      0 if selection succeeded or failed because the target 
 *      did not respond.
 *
 * Side effects : 
 *      If bus busy, arbitration failed, etc, NCR5380_select() will exit 
 *              with registers as they should have been on entry - ie
 *              SELECT_ENABLE will be set appropriately, the NCR5380
 *              will cease to drive any SCSI bus signals.
 *
 *      If successful : I_T_L or I_T_L_Q nexus will be established, 
 *              instance->connected will be set to cmd.  
 *              SELECT interrupt will be disabled.
 *
 *      If failed (no target) : cmd->scsi_done() will be called, and the 
 *              cmd->result host byte set to DID_BAD_TARGET.
 *
 *      Locks: caller holds hostdata lock in IRQ mode
 */
 
static int NCR5380_select(struct Scsi_Host *instance, Scsi_Cmnd * cmd, int tag) 
{
        NCR5380_local_declare();
        struct NCR5380_hostdata *hostdata = (struct NCR5380_hostdata *) instance->hostdata;
        unsigned char tmp[3], phase;
        unsigned char *data;
        int len;
        unsigned long timeout;
        unsigned char value;
        int err;
        NCR5380_setup(instance);

        if (hostdata->selecting)
                goto part2;

        hostdata->restart_select = 0;

        NCR5380_dprint(NDEBUG_ARBITRATION, instance);
        dprintk(NDEBUG_ARBITRATION, ("scsi%d : starting arbitration, id = %d\n", instance->host_no, instance->this_id));

        /* 
         * Set the phase bits to 0, otherwise the NCR5380 won't drive the 
         * data bus during SELECTION.
         */

        NCR5380_write(TARGET_COMMAND_REG, 0);

        /* 
         * Start arbitration.
         */

        NCR5380_write(OUTPUT_DATA_REG, hostdata->id_mask);
        NCR5380_write(MODE_REG, MR_ARBITRATE);


        /* We can be relaxed here, interrupts are on, we are
           in workqueue context, the birds are singing in the trees */
        spin_unlock_irq(instance->host_lock);
        err = NCR5380_poll_politely(instance, INITIATOR_COMMAND_REG, ICR_ARBITRATION_PROGRESS, ICR_ARBITRATION_PROGRESS, 5*HZ);
        spin_lock_irq(instance->host_lock);
        if (err < 0) {
                printk(KERN_DEBUG "scsi: arbitration timeout at %d\n", __LINE__);
                NCR5380_write(MODE_REG, MR_BASE);
                NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
                goto failed;
        }

        dprintk(NDEBUG_ARBITRATION, ("scsi%d : arbitration complete\n", instance->host_no));

        /* 
         * The arbitration delay is 2.2us, but this is a minimum and there is 
         * no maximum so we can safely sleep for ceil(2.2) usecs to accommodate
         * the integral nature of udelay().
         *
         */

        udelay(3);

        /* Check for lost arbitration */
        if ((NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_LOST) || (NCR5380_read(CURRENT_SCSI_DATA_REG) & hostdata->id_higher_mask) || (NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_LOST)) {
                NCR5380_write(MODE_REG, MR_BASE);
                dprintk(NDEBUG_ARBITRATION, ("scsi%d : lost arbitration, deasserting MR_ARBITRATE\n", instance->host_no));
                goto failed;
        }
        NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_SEL);

        if (!(hostdata->flags & FLAG_DTC3181E) &&
            /* RvC: DTC3181E has some trouble with this
             *      so we simply removed it. Seems to work with
             *      only Mustek scanner attached
             */
            (NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_LOST)) {
                NCR5380_write(MODE_REG, MR_BASE);
                NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
                dprintk(NDEBUG_ARBITRATION, ("scsi%d : lost arbitration, deasserting ICR_ASSERT_SEL\n", instance->host_no));
                goto failed;
        }
        /* 
         * Again, bus clear + bus settle time is 1.2us, however, this is 
         * a minimum so we'll udelay ceil(1.2)
         */

        udelay(2);

        dprintk(NDEBUG_ARBITRATION, ("scsi%d : won arbitration\n", instance->host_no));

        /* 
         * Now that we have won arbitration, start Selection process, asserting 
         * the host and target ID's on the SCSI bus.
         */

        NCR5380_write(OUTPUT_DATA_REG, (hostdata->id_mask | (1 << scmd_id(cmd))));

        /* 
         * Raise ATN while SEL is true before BSY goes false from arbitration,
         * since this is the only way to guarantee that we'll get a MESSAGE OUT
         * phase immediately after selection.
         */

        NCR5380_write(INITIATOR_COMMAND_REG, (ICR_BASE | ICR_ASSERT_BSY | ICR_ASSERT_DATA | ICR_ASSERT_ATN | ICR_ASSERT_SEL));
        NCR5380_write(MODE_REG, MR_BASE);

        /* 
         * Reselect interrupts must be turned off prior to the dropping of BSY,
         * otherwise we will trigger an interrupt.
         */
        NCR5380_write(SELECT_ENABLE_REG, 0);

        /*
         * The initiator shall then wait at least two deskew delays and release 
         * the BSY signal.
         */
        udelay(1);              /* wingel -- wait two bus deskew delay >2*45ns */

        /* Reset BSY */
        NCR5380_write(INITIATOR_COMMAND_REG, (ICR_BASE | ICR_ASSERT_DATA | ICR_ASSERT_ATN | ICR_ASSERT_SEL));

        /* 
         * Something weird happens when we cease to drive BSY - looks
         * like the board/chip is letting us do another read before the 
         * appropriate propagation delay has expired, and we're confusing
         * a BSY signal from ourselves as the target's response to SELECTION.
         *
         * A small delay (the 'C++' frontend breaks the pipeline with an
         * unnecessary jump, making it work on my 386-33/Trantor T128, the
         * tighter 'C' code breaks and requires this) solves the problem - 
         * the 1 us delay is arbitrary, and only used because this delay will 
         * be the same on other platforms and since it works here, it should 
         * work there.
         *
         * wingel suggests that this could be due to failing to wait
         * one deskew delay.
         */

        udelay(1);

        dprintk(NDEBUG_SELECTION, ("scsi%d : selecting target %d\n", instance->host_no, scmd_id(cmd)));

        /* 
         * The SCSI specification calls for a 250 ms timeout for the actual 
         * selection.
         */

        timeout = jiffies + (250 * HZ / 1000);


        hostdata->select_time = 0;      /* we count the clock ticks at which we polled */
        hostdata->selecting = cmd;

part2:
        /* RvC: here we enter after a sleeping period, or immediately after
           execution of part 1
           we poll only once ech clock tick */
        value = NCR5380_read(STATUS_REG) & (SR_BSY | SR_IO);

        if (!value && (hostdata->select_time < HZ/4)) {
                /* RvC: we still must wait for a device response */
                hostdata->select_time++;        /* after 25 ticks the device has failed */
                NCR5380_set_timer(hostdata, 1);
                return 0;       /* RvC: we return here with hostdata->selecting set,
                                   to go to sleep */
        }

        hostdata->selecting = NULL;/* clear this pointer, because we passed the
                                           waiting period */
        if ((NCR5380_read(STATUS_REG) & (SR_SEL | SR_IO)) == (SR_SEL | SR_IO)) {
                NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
                NCR5380_reselect(instance);
                printk("scsi%d : reselection after won arbitration?\n", instance->host_no);
                NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
                return -1;
        }
        /* 
         * No less than two deskew delays after the initiator detects the 
         * BSY signal is true, it shall release the SEL signal and may 
         * change the DATA BUS.                                     -wingel
         */

        udelay(1);

        NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ATN);

        if (!(NCR5380_read(STATUS_REG) & SR_BSY)) {
                NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
                if (hostdata->targets_present & (1 << scmd_id(cmd))) {
                        printk(KERN_DEBUG "scsi%d : weirdness\n", instance->host_no);
                        if (hostdata->restart_select)
                                printk(KERN_DEBUG "\trestart select\n");
                        NCR5380_dprint(NDEBUG_SELECTION, instance);
                        NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
                        return -1;
                }
                cmd->result = DID_BAD_TARGET << 16;
                collect_stats(hostdata, cmd);
                cmd->scsi_done(cmd);
                NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
                dprintk(NDEBUG_SELECTION, ("scsi%d : target did not respond within 250ms\n", instance->host_no));
                NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
                return 0;
        }
        hostdata->targets_present |= (1 << scmd_id(cmd));


        /* Wait for start of REQ/ACK handshake */

        spin_unlock_irq(instance->host_lock);
        err = NCR5380_poll_politely(instance, STATUS_REG, SR_REQ, SR_REQ, HZ);
        spin_lock_irq(instance->host_lock);
        
        if(err) {
                printk(KERN_ERR "scsi%d: timeout at NCR5380.c:%d\n", instance->host_no, __LINE__);
                NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
                goto failed;
        }

        dprintk(NDEBUG_SELECTION, ("scsi%d : target %d selected, going into MESSAGE OUT phase.\n", instance->host_no, cmd->device->id));
        tmp[0] = IDENTIFY(((instance->irq == SCSI_IRQ_NONE) ? 0 : 1), cmd->device->lun);

        len = 1;
        cmd->tag = 0;

        /* Send message(s) */
        data = tmp;
        phase = PHASE_MSGOUT;
        NCR5380_transfer_pio(instance, &phase, &len, &data);
        dprintk(NDEBUG_SELECTION, ("scsi%d : nexus established.\n", instance->host_no));
        hostdata->connected = cmd;
        hostdata->busy[cmd->device->id] |= (1 << cmd->device->lun);

        initialize_SCp(cmd);

        return 0;

        /* Selection failed */
failed:
        return -1;

}


/*
 * Note : this code is not as quick as it could be, however it 
 * IS 100% reliable, and for the actual data transfer where speed
 * counts, we will always do a pseudo DMA or DMA transfer.
 */

static int NCR5380_transfer_pio(struct Scsi_Host *instance, unsigned char *phase, int *count, unsigned char **data) {
        NCR5380_local_declare();
        unsigned char p = *phase, tmp;
        int c = *count;
        unsigned char *d = *data;
        /*
         *      RvC: some administrative data to process polling time
         */
        int break_allowed = 0;
        struct NCR5380_hostdata *hostdata = (struct NCR5380_hostdata *) instance->hostdata;
        NCR5380_setup(instance);

        if (!(p & SR_IO))
                dprintk(NDEBUG_PIO, ("scsi%d : pio write %d bytes\n", instance->host_no, c));
        else
                dprintk(NDEBUG_PIO, ("scsi%d : pio read %d bytes\n", instance->host_no, c));

        /* 
         * The NCR5380 chip will only drive the SCSI bus when the 
         * phase specified in the appropriate bits of the TARGET COMMAND
         * REGISTER match the STATUS REGISTER
         */

         NCR5380_write(TARGET_COMMAND_REG, PHASE_SR_TO_TCR(p));

        /* RvC: don't know if this is necessary, but other SCSI I/O is short
         *      so breaks are not necessary there
         */
        if ((p == PHASE_DATAIN) || (p == PHASE_DATAOUT)) {
                break_allowed = 1;
        }
        do {
                /* 
                 * Wait for assertion of REQ, after which the phase bits will be 
                 * valid 
                 */

                /* RvC: we simply poll once, after that we stop temporarily
                 *      and let the device buffer fill up
                 *      if breaking is not allowed, we keep polling as long as needed
                 */

                while (!((tmp = NCR5380_read(STATUS_REG)) & SR_REQ) && !break_allowed);
                if (!(tmp & SR_REQ)) {
                        /* timeout condition */
                        NCR5380_set_timer(hostdata, USLEEP_SLEEP);
                        break;
                }

                dprintk(NDEBUG_HANDSHAKE, ("scsi%d : REQ detected\n", instance->host_no));

                /* Check for phase mismatch */
                if ((tmp & PHASE_MASK) != p) {
                        dprintk(NDEBUG_HANDSHAKE, ("scsi%d : phase mismatch\n", instance->host_no));
                        NCR5380_dprint_phase(NDEBUG_HANDSHAKE, instance);
                        break;
                }
                /* Do actual transfer from SCSI bus to / from memory */
                if (!(p & SR_IO))
                        NCR5380_write(OUTPUT_DATA_REG, *d);
                else
                        *d = NCR5380_read(CURRENT_SCSI_DATA_REG);

                ++d;

                /* 
                 * The SCSI standard suggests that in MSGOUT phase, the initiator
                 * should drop ATN on the last byte of the message phase
                 * after REQ has been asserted for the handshake but before
                 * the initiator raises ACK.
                 */

                if (!(p & SR_IO)) {
                        if (!((p & SR_MSG) && c > 1)) {
                                NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_DATA);
                                NCR5380_dprint(NDEBUG_PIO, instance);
                                NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_DATA | ICR_ASSERT_ACK);
                        } else {
                                NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_DATA | ICR_ASSERT_ATN);
                                NCR5380_dprint(NDEBUG_PIO, instance);
                                NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_DATA | ICR_ASSERT_ATN | ICR_ASSERT_ACK);
                        }
                } else {
                        NCR5380_dprint(NDEBUG_PIO, instance);
                        NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ACK);
                }

                NCR5380_poll_politely(instance, STATUS_REG, SR_REQ, 0, 5*HZ);
                dprintk(NDEBUG_HANDSHAKE, ("scsi%d : req false, handshake complete\n", instance->host_no));

/*
 * We have several special cases to consider during REQ/ACK handshaking : 
 * 1.  We were in MSGOUT phase, and we are on the last byte of the 
 *      message.  ATN must be dropped as ACK is dropped.
 *
 * 2.  We are in a MSGIN phase, and we are on the last byte of the  
 *      message.  We must exit with ACK asserted, so that the calling
 *      code may raise ATN before dropping ACK to reject the message.
 *
 * 3.  ACK and ATN are clear and the target may proceed as normal.
 */
                if (!(p == PHASE_MSGIN && c == 1)) {
                        if (p == PHASE_MSGOUT && c > 1)
                                NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ATN);
                        else
                                NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
                }
        } while (--c);

        dprintk(NDEBUG_PIO, ("scsi%d : residual %d\n", instance->host_no, c));

        *count = c;
        *data = d;
        tmp = NCR5380_read(STATUS_REG);
        if (tmp & SR_REQ)
                *phase = tmp & PHASE_MASK;
        else
                *phase = PHASE_UNKNOWN;

        if (!c || (*phase == p))
                return 0;
        else
                return -1;
}

/**
 *      do_reset        -       issue a reset command
 *      @host: adapter to reset
 *
 *      Issue a reset sequence to the NCR5380 and try and get the bus
 *      back into sane shape.
 *
 *      Locks: caller holds queue lock
 */
 
static void do_reset(struct Scsi_Host *host) {
        NCR5380_local_declare();
        NCR5380_setup(host);

        NCR5380_write(TARGET_COMMAND_REG, PHASE_SR_TO_TCR(NCR5380_read(STATUS_REG) & PHASE_MASK));
        NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_RST);
        udelay(25);
        NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
}


static int do_abort(struct Scsi_Host *host) {
        NCR5380_local_declare();
        unsigned char *msgptr, phase, tmp;
        int len;
        int rc;
        NCR5380_setup(host);


        /* Request message out phase */
        NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ATN);

        /* 
         * Wait for the target to indicate a valid phase by asserting 
         * REQ.  Once this happens, we'll have either a MSGOUT phase 
         * and can immediately send the ABORT message, or we'll have some 
         * other phase and will have to source/sink data.
         * 
         * We really don't care what value was on the bus or what value
         * the target sees, so we just handshake.
         */

        rc = NCR5380_poll_politely(host, STATUS_REG, SR_REQ, SR_REQ, 60 * HZ);
        
        if(rc < 0)
                return -1;

        tmp = (unsigned char)rc;
        
        NCR5380_write(TARGET_COMMAND_REG, PHASE_SR_TO_TCR(tmp));

        if ((tmp & PHASE_MASK) != PHASE_MSGOUT) {
                NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ATN | ICR_ASSERT_ACK);
                rc = NCR5380_poll_politely(host, STATUS_REG, SR_REQ, 0, 3*HZ);
                NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ATN);
                if(rc == -1)
                        return -1;
        }
        tmp = ABORT;
        msgptr = &tmp;
        len = 1;
        phase = PHASE_MSGOUT;
        NCR5380_transfer_pio(host, &phase, &len, &msgptr);

        /*
         * If we got here, and the command completed successfully,
         * we're about to go into bus free state.
         */

        return len ? -1 : 0;
}

#if defined(REAL_DMA) || defined(PSEUDO_DMA) || defined(REAL_DMA_POLL)
/* 
 * Function : int NCR5380_transfer_dma (struct Scsi_Host *instance, 
 *      unsigned char *phase, int *count, unsigned char **data)
 *
 * Purpose : transfers data in given phase using either real
 *      or pseudo DMA.
 *
 * Inputs : instance - instance of driver, *phase - pointer to 
 *      what phase is expected, *count - pointer to number of 
 *      bytes to transfer, **data - pointer to data pointer.
 * 
 * Returns : -1 when different phase is entered without transferring
 *      maximum number of bytes, 0 if all bytes or transfered or exit
 *      is in same phase.
 *
 *      Also, *phase, *count, *data are modified in place.
 *
 *      Locks: io_request lock held by caller
 */


static int NCR5380_transfer_dma(struct Scsi_Host *instance, unsigned char *phase, int *count, unsigned char **data) {
        NCR5380_local_declare();
        register int c = *count;
        register unsigned char p = *phase;
        register unsigned char *d = *data;
        unsigned char tmp;
        int foo;
#if defined(REAL_DMA_POLL)
        int cnt, toPIO;
        unsigned char saved_data = 0, overrun = 0, residue;
#endif

        struct NCR5380_hostdata *hostdata = (struct NCR5380_hostdata *) instance->hostdata;

        NCR5380_setup(instance);

        if ((tmp = (NCR5380_read(STATUS_REG) & PHASE_MASK)) != p) {
                *phase = tmp;
                return -1;
        }
#if defined(REAL_DMA) || defined(REAL_DMA_POLL)
#ifdef READ_OVERRUNS
        if (p & SR_IO) {
                c -= 2;
        }
#endif
        dprintk(NDEBUG_DMA, ("scsi%d : initializing DMA channel %d for %s, %d bytes %s %0x\n", instance->host_no, instance->dma_channel, (p & SR_IO) ? "reading" : "writing", c, (p & SR_IO) ? "to" : "from", (unsigned) d));
        hostdata->dma_len = (p & SR_IO) ? NCR5380_dma_read_setup(instance, d, c) : NCR5380_dma_write_setup(instance, d, c);
#endif

        NCR5380_write(TARGET_COMMAND_REG, PHASE_SR_TO_TCR(p));

#ifdef REAL_DMA
        NCR5380_write(MODE_REG, MR_BASE | MR_DMA_MODE | MR_ENABLE_EOP_INTR | MR_MONITOR_BSY);
#elif defined(REAL_DMA_POLL)
        NCR5380_write(MODE_REG, MR_BASE | MR_DMA_MODE);
#else
        /*
         * Note : on my sample board, watch-dog timeouts occurred when interrupts
         * were not disabled for the duration of a single DMA transfer, from 
         * before the setting of DMA mode to after transfer of the last byte.
         */

#if defined(PSEUDO_DMA) && defined(UNSAFE)
        spin_unlock_irq(instance->host_lock);
#endif
        /* KLL May need eop and parity in 53c400 */
        if (hostdata->flags & FLAG_NCR53C400)
                NCR5380_write(MODE_REG, MR_BASE | MR_DMA_MODE |
                                MR_ENABLE_PAR_CHECK | MR_ENABLE_PAR_INTR |
                                MR_ENABLE_EOP_INTR | MR_MONITOR_BSY);
        else
                NCR5380_write(MODE_REG, MR_BASE | MR_DMA_MODE);
#endif                          /* def REAL_DMA */

        dprintk(NDEBUG_DMA, ("scsi%d : mode reg = 0x%X\n", instance->host_no, NCR5380_read(MODE_REG)));

        /* 
         *      On the PAS16 at least I/O recovery delays are not needed here.
         *      Everyone else seems to want them.
         */

        if (p & SR_IO) {
                io_recovery_delay(1);
                NCR5380_write(START_DMA_INITIATOR_RECEIVE_REG, 0);
        } else {
                io_recovery_delay(1);
                NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_DATA);
                io_recovery_delay(1);
                NCR5380_write(START_DMA_SEND_REG, 0);
                io_recovery_delay(1);
        }

#if defined(REAL_DMA_POLL)
        do {
                tmp = NCR5380_read(BUS_AND_STATUS_REG);
        } while ((tmp & BASR_PHASE_MATCH) && !(tmp & (BASR_BUSY_ERROR | BASR_END_DMA_TRANSFER)));


        if (p & SR_IO) {
#ifdef READ_OVERRUNS
                udelay(10);
                if (((NCR5380_read(BUS_AND_STATUS_REG) & (BASR_PHASE_MATCH | BASR_ACK)) == (BASR_PHASE_MATCH | BASR_ACK))) {
                        saved_data = NCR5380_read(INPUT_DATA_REGISTER);
                        overrun = 1;
                }
#endif
        } else {
                int limit = 100;
                while (((tmp = NCR5380_read(BUS_AND_STATUS_REG)) & BASR_ACK) || (NCR5380_read(STATUS_REG) & SR_REQ)) {
                        if (!(tmp & BASR_PHASE_MATCH))
                                break;
                        if (--limit < 0)
                                break;
                }
        }

        dprintk(NDEBUG_DMA, ("scsi%d : polled DMA transfer complete, basr 0x%X, sr 0x%X\n", instance->host_no, tmp, NCR5380_read(STATUS_REG)));

        NCR5380_write(MODE_REG, MR_BASE);
        NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);

        residue = NCR5380_dma_residual(instance);
        c -= residue;
        *count -= c;
        *data += c;
        *phase = NCR5380_read(STATUS_REG) & PHASE_MASK;

#ifdef READ_OVERRUNS
        if (*phase == p && (p & SR_IO) && residue == 0) {
                if (overrun) {
                        dprintk(NDEBUG_DMA, ("Got an input overrun, using saved byte\n"));
                        **data = saved_data;
                        *data += 1;
                        *count -= 1;
                        cnt = toPIO = 1;
                } else {
                        printk("No overrun??\n");
                        cnt = toPIO = 2;
                }
                dprintk(NDEBUG_DMA, ("Doing %d-byte PIO to 0x%X\n", cnt, *data));
                NCR5380_transfer_pio(instance, phase, &cnt, data);
                *count -= toPIO - cnt;
        }
#endif

        dprintk(NDEBUG_DMA, ("Return with data ptr = 0x%X, count %d, last 0x%X, next 0x%X\n", *data, *count, *(*data + *count - 1), *(*data + *count)));
        return 0;

#elif defined(REAL_DMA)
        return 0;
#else                           /* defined(REAL_DMA_POLL) */
        if (p & SR_IO) {
#ifdef DMA_WORKS_RIGHT
                foo = NCR5380_pread(instance, d, c);
#else
                int diff = 1;
                if (hostdata->flags & FLAG_NCR53C400) {
                        diff = 0;
                }
                if (!(foo = NCR5380_pread(instance, d, c - diff))) {

                        if (!(hostdata->flags & FLAG_NCR53C400)) {
                                while (!(NCR5380_read(BUS_AND_STATUS_REG) & BASR_DRQ));
                                /* Wait for clean handshake */
                                while (NCR5380_read(STATUS_REG) & SR_REQ);
                                d[c - 1] = NCR5380_read(INPUT_DATA_REG);
                        }
                }
#endif
        } else {
#ifdef DMA_WORKS_RIGHT
                foo = NCR5380_pwrite(instance, d, c);
#else
                int timeout;
                dprintk(NDEBUG_C400_PWRITE, ("About to pwrite %d bytes\n", c));
                if (!(foo = NCR5380_pwrite(instance, d, c))) {
                        /*
                         * Wait for the last byte to be sent.  If REQ is being asserted for 
                         * the byte we're interested, we'll ACK it and it will go false.  
                         */
                        if (!(hostdata->flags & FLAG_HAS_LAST_BYTE_SENT)) {
                                timeout = 20000;
                                while (!(NCR5380_read(BUS_AND_STATUS_REG) & BASR_DRQ) && (NCR5380_read(BUS_AND_STATUS_REG) & BASR_PHASE_MATCH));

                                if (!timeout)
                                        dprintk(NDEBUG_LAST_BYTE_SENT, ("scsi%d : timed out on last byte\n", instance->host_no));

                                if (hostdata->flags & FLAG_CHECK_LAST_BYTE_SENT) {
                                        hostdata->flags &= ~FLAG_CHECK_LAST_BYTE_SENT;
                                        if (NCR5380_read(TARGET_COMMAND_REG) & TCR_LAST_BYTE_SENT) {
                                                hostdata->flags |= FLAG_HAS_LAST_BYTE_SENT;
                                                dprintk(NDEBUG_LAST_WRITE_SENT, ("scsi%d : last bit sent works\n", instance->host_no));
                                        }
                                }
                        } else {
                                dprintk(NDEBUG_C400_PWRITE, ("Waiting for LASTBYTE\n"));
                                while (!(NCR5380_read(TARGET_COMMAND_REG) & TCR_LAST_BYTE_SENT));
                                dprintk(NDEBUG_C400_PWRITE, ("Got LASTBYTE\n"));
                        }
                }
#endif
        }
        NCR5380_write(MODE_REG, MR_BASE);
        NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);

        if ((!(p & SR_IO)) && (hostdata->flags & FLAG_NCR53C400)) {
                dprintk(NDEBUG_C400_PWRITE, ("53C400w: Checking for IRQ\n"));
                if (NCR5380_read(BUS_AND_STATUS_REG) & BASR_IRQ) {
                        dprintk(NDEBUG_C400_PWRITE, ("53C400w:    got it, reading reset interrupt reg\n"));
                        NCR5380_read(RESET_PARITY_INTERRUPT_REG);
                } else {
                        printk("53C400w:    IRQ NOT THERE!\n");
                }
        }
        *data = d + c;
        *count = 0;
        *phase = NCR5380_read(STATUS_REG) & PHASE_MASK;
#if defined(PSEUDO_DMA) && defined(UNSAFE)
        spin_lock_irq(instance->host_lock);
#endif                          /* defined(REAL_DMA_POLL) */
        return foo;
#endif                          /* def REAL_DMA */
}
#endif                          /* defined(REAL_DMA) | defined(PSEUDO_DMA) */


static void NCR5380_information_transfer(struct Scsi_Host *instance) {
        NCR5380_local_declare();
        struct NCR5380_hostdata *hostdata = (struct NCR5380_hostdata *)instance->hostdata;
        unsigned char msgout = NOP;
        int sink = 0;
        int len;
#if defined(PSEUDO_DMA) || defined(REAL_DMA_POLL)
        int transfersize;
#endif
        unsigned char *data;
        unsigned char phase, tmp, extended_msg[10], old_phase = 0xff;
        Scsi_Cmnd *cmd = (Scsi_Cmnd *) hostdata->connected;
        /* RvC: we need to set the end of the polling time */
        unsigned long poll_time = jiffies + USLEEP_POLL;

        NCR5380_setup(instance);

        while (1) {
                tmp = NCR5380_read(STATUS_REG);
                /* We only have a valid SCSI phase when REQ is asserted */
                if (tmp & SR_REQ) {
                        phase = (tmp & PHASE_MASK);
                        if (phase != old_phase) {
                                old_phase = phase;
                                NCR5380_dprint_phase(NDEBUG_INFORMATION, instance);
                        }
                        if (sink && (phase != PHASE_MSGOUT)) {
                                NCR5380_write(TARGET_COMMAND_REG, PHASE_SR_TO_TCR(tmp));

                                NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ATN | ICR_ASSERT_ACK);
                                while (NCR5380_read(STATUS_REG) & SR_REQ);
                                NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ATN);
                                sink = 0;
                                continue;
                        }
                        switch (phase) {
                        case PHASE_DATAIN:
                        case PHASE_DATAOUT:
#if (NDEBUG & NDEBUG_NO_DATAOUT)
                                printk("scsi%d : NDEBUG_NO_DATAOUT set, attempted DATAOUT aborted\n", instance->host_no);
                                sink = 1;
                                do_abort(instance);
                                cmd->result = DID_ERROR << 16;
                                cmd->scsi_done(cmd);
                                return;
#endif
                                /* 
                                 * If there is no room left in the current buffer in the
                                 * scatter-gather list, move onto the next one.
                                 */

                                if (!cmd->SCp.this_residual && cmd->SCp.buffers_residual) {
                                        ++cmd->SCp.buffer;
                                        --cmd->SCp.buffers_residual;
                                        cmd->SCp.this_residual = cmd->SCp.buffer->length;
                                        cmd->SCp.ptr = sg_virt(cmd->SCp.buffer);
                                        dprintk(NDEBUG_INFORMATION, ("scsi%d : %d bytes and %d buffers left\n", instance->host_no, cmd->SCp.this_residual, cmd->SCp.buffers_residual));
                                }
                                /*
                                 * The preferred transfer method is going to be 
                                 * PSEUDO-DMA for systems that are strictly PIO,
                                 * since we can let the hardware do the handshaking.
                                 *
                                 * For this to work, we need to know the transfersize
                                 * ahead of time, since the pseudo-DMA code will sit
                                 * in an unconditional loop.
                                 */

#if defined(PSEUDO_DMA) || defined(REAL_DMA_POLL)
                                /* KLL
                                 * PSEUDO_DMA is defined here. If this is the g_NCR5380
                                 * driver then it will always be defined, so the
                                 * FLAG_NO_PSEUDO_DMA is used to inhibit PDMA in the base
                                 * NCR5380 case.  I think this is a fairly clean solution.
                                 * We supplement these 2 if's with the flag.
                                 */
#ifdef NCR5380_dma_xfer_len
                                if (!cmd->device->borken && !(hostdata->flags & FLAG_NO_PSEUDO_DMA) && (transfersize = NCR5380_dma_xfer_len(instance, cmd)) != 0) {
#else
                                transfersize = cmd->transfersize;

#ifdef LIMIT_TRANSFERSIZE           /* If we have problems with interrupt service */
                                if (transfersize > 512)
                                        transfersize = 512;
#endif                          /* LIMIT_TRANSFERSIZE */

                                if (!cmd->device->borken && transfersize && !(hostdata->flags & FLAG_NO_PSEUDO_DMA) && cmd->SCp.this_residual && !(cmd->SCp.this_residual % transfersize)) {
                                        /* Limit transfers to 32K, for xx400 & xx406
                                         * pseudoDMA that transfers in 128 bytes blocks. */
                                        if (transfersize > 32 * 1024)
                                                transfersize = 32 * 1024;
#endif
                                        len = transfersize;
                                        if (NCR5380_transfer_dma(instance, &phase, &len, (unsigned char **) &cmd->SCp.ptr)) {
                                                /*
                                                 * If the watchdog timer fires, all future accesses to this
                                                 * device will use the polled-IO.
                                                 */
                                                scmd_printk(KERN_INFO, cmd,
                                                            "switching to slow handshake\n");
                                                cmd->device->borken = 1;
                                                NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ATN);
                                                sink = 1;
                                                do_abort(instance);
                                                cmd->result = DID_ERROR << 16;
                                                cmd->scsi_done(cmd);
                                        } else
                                                cmd->SCp.this_residual -= transfersize - len;
                                } else
#endif                          /* defined(PSEUDO_DMA) || defined(REAL_DMA_POLL) */
                                        NCR5380_transfer_pio(instance, &phase, (int *) &cmd->SCp.this_residual, (unsigned char **)
                                                             &cmd->SCp.ptr);
                                break;
                        case PHASE_MSGIN:
                                len = 1;
                                data = &tmp;
                                NCR5380_transfer_pio(instance, &phase, &len, &data);
                                cmd->SCp.Message = tmp;

                                switch (tmp) {
                                        /*
                                         * Linking lets us reduce the time required to get the 
                                         * next command out to the device, hopefully this will
                                         * mean we don't waste another revolution due to the delays
                                         * required by ARBITRATION and another SELECTION.
                                         *
                                         * In the current implementation proposal, low level drivers
                                         * merely have to start the next command, pointed to by 
                                         * next_link, done() is called as with unlinked commands.
                                         */
#ifdef LINKED
                                case LINKED_CMD_COMPLETE:
                                case LINKED_FLG_CMD_COMPLETE:
                                        /* Accept message by clearing ACK */
                                        NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
                                        dprintk(NDEBUG_LINKED, ("scsi%d : target %d lun %d linked command complete.\n", instance->host_no, cmd->device->id, cmd->device->lun));
                                        /* 
                                         * Sanity check : A linked command should only terminate with
                                         * one of these messages if there are more linked commands
                                         * available.
                                         */
                                        if (!cmd->next_link) {
                                                printk("scsi%d : target %d lun %d linked command complete, no next_link\n" instance->host_no, cmd->device->id, cmd->device->lun);
                                                sink = 1;
                                                do_abort(instance);
                                                return;
                                        }
                                        initialize_SCp(cmd->next_link);
                                        /* The next command is still part of this process */
                                        cmd->next_link->tag = cmd->tag;
                                        cmd->result = cmd->SCp.Status | (cmd->SCp.Message << 8);
                                        dprintk(NDEBUG_LINKED, ("scsi%d : target %d lun %d linked request done, calling scsi_done().\n", instance->host_no, cmd->device->id, cmd->device->lun));
                                        collect_stats(hostdata, cmd);
                                        cmd->scsi_done(cmd);
                                        cmd = hostdata->connected;
                                        break;
#endif                          /* def LINKED */
                                case ABORT:
                                case COMMAND_COMPLETE:
                                        /* Accept message by clearing ACK */
                                        sink = 1;
                                        NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
                                        hostdata->connected = NULL;
                                        dprintk(NDEBUG_QUEUES, ("scsi%d : command for target %d, lun %d completed\n", instance->host_no, cmd->device->id, cmd->device->lun));
                                        hostdata->busy[cmd->device->id] &= ~(1 << cmd->device->lun);

                                        /* 
                                         * I'm not sure what the correct thing to do here is : 
                                         * 
                                         * If the command that just executed is NOT a request 
                                         * sense, the obvious thing to do is to set the result
                                         * code to the values of the stored parameters.
                                         * 
                                         * If it was a REQUEST SENSE command, we need some way 
                                         * to differentiate between the failure code of the original
                                         * and the failure code of the REQUEST sense - the obvious
                                         * case is success, where we fall through and leave the result
                                         * code unchanged.
                                         * 
                                         * The non-obvious place is where the REQUEST SENSE failed 
                                         */

                                        if (cmd->cmnd[0] != REQUEST_SENSE)
                                                cmd->result = cmd->SCp.Status | (cmd->SCp.Message << 8);
                                        else if (status_byte(cmd->SCp.Status) != GOOD)
                                                cmd->result = (cmd->result & 0x00ffff) | (DID_ERROR << 16);

#ifdef AUTOSENSE
                                        if ((cmd->cmnd[0] == REQUEST_SENSE) &&
                                                hostdata->ses.cmd_len) {
                                                scsi_eh_restore_cmnd(cmd, &hostdata->ses);
                                                hostdata->ses.cmd_len = 0 ;
                                        }

                                        if ((cmd->cmnd[0] != REQUEST_SENSE) && (status_byte(cmd->SCp.Status) == CHECK_CONDITION)) {
                                                scsi_eh_prep_cmnd(cmd, &hostdata->ses, NULL, 0, ~0);

                                                dprintk(NDEBUG_AUTOSENSE, ("scsi%d : performing request sense\n", instance->host_no));

                                                LIST(cmd, hostdata->issue_queue);
                                                cmd->host_scribble = (unsigned char *)
                                                    hostdata->issue_queue;
                                                hostdata->issue_queue = (Scsi_Cmnd *) cmd;
                                                dprintk(NDEBUG_QUEUES, ("scsi%d : REQUEST SENSE added to head of issue queue\n", instance->host_no));
                                        } else
#endif                          /* def AUTOSENSE */
                                        {
                                                collect_stats(hostdata, cmd);
                                                cmd->scsi_done(cmd);
                                        }

                                        NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
                                        /* 
                                         * Restore phase bits to 0 so an interrupted selection, 
                                         * arbitration can resume.
                                         */
                                        NCR5380_write(TARGET_COMMAND_REG, 0);

                                        while ((NCR5380_read(STATUS_REG) & SR_BSY) && !hostdata->connected)
                                                barrier();
                                        return;
                                case MESSAGE_REJECT:
                                        /* Accept message by clearing ACK */
                                        NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
                                        switch (hostdata->last_message) {
                                        case HEAD_OF_QUEUE_TAG:
                                        case ORDERED_QUEUE_TAG:
                                        case SIMPLE_QUEUE_TAG:
                                                cmd->device->simple_tags = 0;
                                                hostdata->busy[cmd->device->id] |= (1 << cmd->device->lun);
                                                break;
                                        default:
                                                break;
                                        }
                                case DISCONNECT:{
                                                /* Accept message by clearing ACK */
                                                NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
                                                cmd->device->disconnect = 1;
                                                LIST(cmd, hostdata->disconnected_queue);
                                                cmd->host_scribble = (unsigned char *)
                                                    hostdata->disconnected_queue;
                                                hostdata->connected = NULL;
                                                hostdata->disconnected_queue = cmd;
                                                dprintk(NDEBUG_QUEUES, ("scsi%d : command for target %d lun %d was moved from connected to" "  the disconnected_queue\n", instance->host_no, cmd->device->id, cmd->device->lun));
                                                /* 
                                                 * Restore phase bits to 0 so an interrupted selection, 
                                                 * arbitration can resume.
                                                 */
                                                NCR5380_write(TARGET_COMMAND_REG, 0);

                                                /* Enable reselect interrupts */
                                                NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
                                                /* NCR538_poll_politely(instance, STATUS_REG, SR_BSY, 0, 30 * HZ); */
                                                while ((NCR5380_read(STATUS_REG) & SR_BSY) && !hostdata->connected)
                                                        barrier();
                                                return;
                                        }
                                        /* 
                                         * The SCSI data pointer is *IMPLICITLY* saved on a disconnect
                                         * operation, in violation of the SCSI spec so we can safely 
                                         * ignore SAVE/RESTORE pointers calls.
                                         *
                                         * Unfortunately, some disks violate the SCSI spec and 
                                         * don't issue the required SAVE_POINTERS message before
                                         * disconnecting, and we have to break spec to remain 
                                         * compatible.
                                         */
                                case SAVE_POINTERS:
                                case RESTORE_POINTERS:
                                        /* Accept message by clearing ACK */
                                        NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
                                        break;
                                case EXTENDED_MESSAGE:
/* 
 * Extended messages are sent in the following format :
 * Byte         
 * 0            EXTENDED_MESSAGE == 1
 * 1            length (includes one byte for code, doesn't 
 *              include first two bytes)
 * 2            code
 * 3..length+1  arguments
 *
 * Start the extended message buffer with the EXTENDED_MESSAGE
 * byte, since spi_print_msg() wants the whole thing.  
 */
                                        extended_msg[0] = EXTENDED_MESSAGE;
                                        /* Accept first byte by clearing ACK */
                                        NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
                                        dprintk(NDEBUG_EXTENDED, ("scsi%d : receiving extended message\n", instance->host_no));

                                        len = 2;
                                        data = extended_msg + 1;
                                        phase = PHASE_MSGIN;
                                        NCR5380_transfer_pio(instance, &phase, &len, &data);

                                        dprintk(NDEBUG_EXTENDED, ("scsi%d : length=%d, code=0x%02x\n", instance->host_no, (int) extended_msg[1], (int) extended_msg[2]));

                                        if (!len && extended_msg[1] <= (sizeof(extended_msg) - 1)) {
                                                /* Accept third byte by clearing ACK */
                                                NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
                                                len = extended_msg[1] - 1;
                                                data = extended_msg + 3;
                                                phase = PHASE_MSGIN;

                                                NCR5380_transfer_pio(instance, &phase, &len, &data);
                                                dprintk(NDEBUG_EXTENDED, ("scsi%d : message received, residual %d\n", instance->host_no, len));

                                                switch (extended_msg[2]) {
                                                case EXTENDED_SDTR:
                                                case EXTENDED_WDTR:
                                                case EXTENDED_MODIFY_DATA_POINTER:
                                                case EXTENDED_EXTENDED_IDENTIFY:
                                                        tmp = 0;
                                                }
                                        } else if (len) {
                                                printk("scsi%d: error receiving extended message\n", instance->host_no);
                                                tmp = 0;
                                        } else {
                                                printk("scsi%d: extended message code %02x length %d is too long\n", instance->host_no, extended_msg[2], extended_msg[1]);
                                                tmp = 0;
                                        }
                                        /* Fall through to reject message */

                                        /* 
                                         * If we get something weird that we aren't expecting, 
                                         * reject it.
                                         */
                                default:
                                        if (!tmp) {
                                                printk("scsi%d: rejecting message ", instance->host_no);
                                                spi_print_msg(extended_msg);
                                                printk("\n");
                                        } else if (tmp != EXTENDED_MESSAGE)
                                                scmd_printk(KERN_INFO, cmd,
                                                        "rejecting unknown message %02x\n",tmp);
                                        else
                                                scmd_printk(KERN_INFO, cmd,
                                                        "rejecting unknown extended message code %02x, length %d\n", extended_msg[1], extended_msg[0]);

                                        msgout = MESSAGE_REJECT;
                                        NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ATN);
                                        break;
                                }       /* switch (tmp) */
                                break;
                        case PHASE_MSGOUT:
                                len = 1;
                                data = &msgout;
                                hostdata->last_message = msgout;
                                NCR5380_transfer_pio(instance, &phase, &len, &data);
                                if (msgout == ABORT) {
                                        hostdata->busy[cmd->device->id] &= ~(1 << cmd->device->lun);
                                        hostdata->connected = NULL;
                                        cmd->result = DID_ERROR << 16;
                                        collect_stats(hostdata, cmd);
                                        cmd->scsi_done(cmd);
                                        NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
                                        return;
                                }
                                msgout = NOP;
                                break;
                        case PHASE_CMDOUT:
                                len = cmd->cmd_len;
                                data = cmd->cmnd;
                                NCR5380_transfer_pio(instance, &phase, &len, &data);
                                if (!cmd->device->disconnect && should_disconnect(cmd->cmnd[0])) {
                                        NCR5380_set_timer(hostdata, USLEEP_SLEEP);
                                        dprintk(NDEBUG_USLEEP, ("scsi%d : issued command, sleeping until %ul\n", instance->host_no, hostdata->time_expires));
                                        return;
                                }
                                break;
                        case PHASE_STATIN:
                                len = 1;
                                data = &tmp;
                                NCR5380_transfer_pio(instance, &phase, &len, &data);
                                cmd->SCp.Status = tmp;
                                break;
                        default:
                                printk("scsi%d : unknown phase\n", instance->host_no);
                                NCR5380_dprint(NDEBUG_ALL, instance);
                        }       /* switch(phase) */
                }               /* if (tmp * SR_REQ) */
                else {
                        /* RvC: go to sleep if polling time expired
                         */
                        if (!cmd->device->disconnect && time_after_eq(jiffies, poll_time)) {
                                NCR5380_set_timer(hostdata, USLEEP_SLEEP);
                                dprintk(NDEBUG_USLEEP, ("scsi%d : poll timed out, sleeping until %ul\n", instance->host_no, hostdata->time_expires));
                                return;
                        }
                }
        }                       /* while (1) */
}

/*
 * Function : void NCR5380_reselect (struct Scsi_Host *instance)
 *
 * Purpose : does reselection, initializing the instance->connected 
 *      field to point to the Scsi_Cmnd for which the I_T_L or I_T_L_Q 
 *      nexus has been reestablished,
 *      
 * Inputs : instance - this instance of the NCR5380.
 *
 * Locks: io_request_lock held by caller if IRQ driven
 */

static void NCR5380_reselect(struct Scsi_Host *instance) {
        NCR5380_local_declare();
        struct NCR5380_hostdata *hostdata = (struct NCR5380_hostdata *)
         instance->hostdata;
        unsigned char target_mask;
        unsigned char lun, phase;
        int len;
        unsigned char msg[3];
        unsigned char *data;
        Scsi_Cmnd *tmp = NULL, *prev;
        int abort = 0;
        NCR5380_setup(instance);

        /*
         * Disable arbitration, etc. since the host adapter obviously
         * lost, and tell an interrupted NCR5380_select() to restart.
         */

        NCR5380_write(MODE_REG, MR_BASE);
        hostdata->restart_select = 1;

        target_mask = NCR5380_read(CURRENT_SCSI_DATA_REG) & ~(hostdata->id_mask);
        dprintk(NDEBUG_SELECTION, ("scsi%d : reselect\n", instance->host_no));

        /* 
         * At this point, we have detected that our SCSI ID is on the bus,
         * SEL is true and BSY was false for at least one bus settle delay
         * (400 ns).
         *
         * We must assert BSY ourselves, until the target drops the SEL
         * signal.
         */

        NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_BSY);

        if(NCR5380_poll_politely(instance, STATUS_REG, SR_SEL, 0, 2*HZ)<0)
                abort = 1;
                
        NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);


        if(NCR5380_poll_politely(instance, STATUS_REG, SR_REQ, SR_REQ, 2*HZ))
                abort = 1;

        len = 1;
        data = msg;
        phase = PHASE_MSGIN;
        NCR5380_transfer_pio(instance, &phase, &len, &data);

        if (!(msg[0] & 0x80)) {
                printk(KERN_ERR "scsi%d : expecting IDENTIFY message, got ", instance->host_no);
                spi_print_msg(msg);
                abort = 1;
        } else {
                /* Accept message by clearing ACK */
                NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
                lun = (msg[0] & 0x07);

                /* 
                 * We need to add code for SCSI-II to track which devices have
                 * I_T_L_Q nexuses established, and which have simple I_T_L
                 * nexuses so we can chose to do additional data transfer.
                 */

                /* 
                 * Find the command corresponding to the I_T_L or I_T_L_Q  nexus we 
                 * just reestablished, and remove it from the disconnected queue.
                 */


                for (tmp = (Scsi_Cmnd *) hostdata->disconnected_queue, prev = NULL; tmp; prev = tmp, tmp = (Scsi_Cmnd *) tmp->host_scribble)
                        if ((target_mask == (1 << tmp->device->id)) && (lun == tmp->device->lun)
                            ) {
                                if (prev) {
                                        REMOVE(prev, prev->host_scribble, tmp, tmp->host_scribble);
                                        prev->host_scribble = tmp->host_scribble;
                                } else {
                                        REMOVE(-1, hostdata->disconnected_queue, tmp, tmp->host_scribble);
                                        hostdata->disconnected_queue = (Scsi_Cmnd *) tmp->host_scribble;
                                }
                                tmp->host_scribble = NULL;
                                break;
                        }
                if (!tmp) {
                        printk(KERN_ERR "scsi%d : warning : target bitmask %02x lun %d not in disconnect_queue.\n", instance->host_no, target_mask, lun);
                        /* 
                         * Since we have an established nexus that we can't do anything with,
                         * we must abort it.  
                         */
                        abort = 1;
                }
        }

        if (abort) {
                do_abort(instance);
        } else {
                hostdata->connected = tmp;
                dprintk(NDEBUG_RESELECTION, ("scsi%d : nexus established, target = %d, lun = %d, tag = %d\n", instance->host_no, tmp->target, tmp->lun, tmp->tag));
        }
}

/*
 * Function : void NCR5380_dma_complete (struct Scsi_Host *instance)
 *
 * Purpose : called by interrupt handler when DMA finishes or a phase
 *      mismatch occurs (which would finish the DMA transfer).  
 *
 * Inputs : instance - this instance of the NCR5380.
 *
 * Returns : pointer to the Scsi_Cmnd structure for which the I_T_L
 *      nexus has been reestablished, on failure NULL is returned.
 */

#ifdef REAL_DMA
static void NCR5380_dma_complete(NCR5380_instance * instance) {
        NCR5380_local_declare();
        struct NCR5380_hostdata *hostdata = (struct NCR5380_hostdata *) instance->hostdata;
        int transferred;
        NCR5380_setup(instance);


        NCR5380_poll_politely(instance, BUS_AND_STATUS_REG, BASR_ACK, 0, 5*HZ);

        NCR5380_write(MODE_REG, MR_BASE);
        NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);

        /*
         * The only places we should see a phase mismatch and have to send
         * data from the same set of pointers will be the data transfer
         * phases.  So, residual, requested length are only important here.
         */

        if (!(hostdata->connected->SCp.phase & SR_CD)) {
                transferred = instance->dmalen - NCR5380_dma_residual();
                hostdata->connected->SCp.this_residual -= transferred;
                hostdata->connected->SCp.ptr += transferred;
        }
}
#endif                          /* def REAL_DMA */


static int NCR5380_abort(Scsi_Cmnd * cmd) {
        NCR5380_local_declare();
        struct Scsi_Host *instance = cmd->device->host;
        struct NCR5380_hostdata *hostdata = (struct NCR5380_hostdata *) instance->hostdata;
        Scsi_Cmnd *tmp, **prev;
        
        printk(KERN_WARNING "scsi%d : aborting command\n", instance->host_no);
        scsi_print_command(cmd);

        NCR5380_print_status(instance);

        NCR5380_setup(instance);

        dprintk(NDEBUG_ABORT, ("scsi%d : abort called\n", instance->host_no));
        dprintk(NDEBUG_ABORT, ("        basr 0x%X, sr 0x%X\n", NCR5380_read(BUS_AND_STATUS_REG), NCR5380_read(STATUS_REG)));


/* 
 * Case 2 : If the command hasn't been issued yet, we simply remove it 
 *          from the issue queue.
 */
 
        dprintk(NDEBUG_ABORT, ("scsi%d : abort going into loop.\n", instance->host_no));
        for (prev = (Scsi_Cmnd **) & (hostdata->issue_queue), tmp = (Scsi_Cmnd *) hostdata->issue_queue; tmp; prev = (Scsi_Cmnd **) & (tmp->host_scribble), tmp = (Scsi_Cmnd *) tmp->host_scribble)
                if (cmd == tmp) {
                        REMOVE(5, *prev, tmp, tmp->host_scribble);
                        (*prev) = (Scsi_Cmnd *) tmp->host_scribble;
                        tmp->host_scribble = NULL;
                        tmp->result = DID_ABORT << 16;
                        dprintk(NDEBUG_ABORT, ("scsi%d : abort removed command from issue queue.\n", instance->host_no));
                        tmp->scsi_done(tmp);
                        return SUCCESS;
                }
#if (NDEBUG  & NDEBUG_ABORT)
        /* KLL */
                else if (prev == tmp)
                        printk(KERN_ERR "scsi%d : LOOP\n", instance->host_no);
#endif

/* 
 * Case 3 : If any commands are connected, we're going to fail the abort
 *          and let the high level SCSI driver retry at a later time or 
 *          issue a reset.
 *
 *          Timeouts, and therefore aborted commands, will be highly unlikely
 *          and handling them cleanly in this situation would make the common
 *          case of noresets less efficient, and would pollute our code.  So,
 *          we fail.
 */

        if (hostdata->connected) {
                dprintk(NDEBUG_ABORT, ("scsi%d : abort failed, command connected.\n", instance->host_no));
                return FAILED;
        }
/*
 * Case 4: If the command is currently disconnected from the bus, and 
 *      there are no connected commands, we reconnect the I_T_L or 
 *      I_T_L_Q nexus associated with it, go into message out, and send 
 *      an abort message.
 *
 * This case is especially ugly. In order to reestablish the nexus, we
 * need to call NCR5380_select().  The easiest way to implement this 
 * function was to abort if the bus was busy, and let the interrupt
 * handler triggered on the SEL for reselect take care of lost arbitrations
 * where necessary, meaning interrupts need to be enabled.
 *
 * When interrupts are enabled, the queues may change - so we 
 * can't remove it from the disconnected queue before selecting it
 * because that could cause a failure in hashing the nexus if that 
 * device reselected.
 * 
 * Since the queues may change, we can't use the pointers from when we
 * first locate it.
 *
 * So, we must first locate the command, and if NCR5380_select()
 * succeeds, then issue the abort, relocate the command and remove
 * it from the disconnected queue.
 */

        for (tmp = (Scsi_Cmnd *) hostdata->disconnected_queue; tmp; tmp = (Scsi_Cmnd *) tmp->host_scribble)
                if (cmd == tmp) {
                        dprintk(NDEBUG_ABORT, ("scsi%d : aborting disconnected command.\n", instance->host_no));

                        if (NCR5380_select(instance, cmd, (int) cmd->tag))
                                return FAILED;
                        dprintk(NDEBUG_ABORT, ("scsi%d : nexus reestablished.\n", instance->host_no));

                        do_abort(instance);

                        for (prev = (Scsi_Cmnd **) & (hostdata->disconnected_queue), tmp = (Scsi_Cmnd *) hostdata->disconnected_queue; tmp; prev = (Scsi_Cmnd **) & (tmp->host_scribble), tmp = (Scsi_Cmnd *) tmp->host_scribble)
                                if (cmd == tmp) {
                                        REMOVE(5, *prev, tmp, tmp->host_scribble);
                                        *prev = (Scsi_Cmnd *) tmp->host_scribble;
                                        tmp->host_scribble = NULL;
                                        tmp->result = DID_ABORT << 16;
                                        tmp->scsi_done(tmp);
                                        return SUCCESS;
                                }
                }
/*
 * Case 5 : If we reached this point, the command was not found in any of 
 *          the queues.
 *
 * We probably reached this point because of an unlikely race condition
 * between the command completing successfully and the abortion code,
 * so we won't panic, but we will notify the user in case something really
 * broke.
 */
        printk(KERN_WARNING "scsi%d : warning : SCSI command probably completed successfully\n"
                        "         before abortion\n", instance->host_no);
        return FAILED;
}


/* 
 * Function : int NCR5380_bus_reset (Scsi_Cmnd *cmd)
 * 
 * Purpose : reset the SCSI bus.
 *
 * Returns : SUCCESS
 *
 * Locks: host lock taken by caller
 */

static int NCR5380_bus_reset(Scsi_Cmnd * cmd)
{
        struct Scsi_Host *instance = cmd->device->host;

        NCR5380_local_declare();
        NCR5380_setup(instance);
        NCR5380_print_status(instance);

        spin_lock_irq(instance->host_lock);
        do_reset(instance);
        spin_unlock_irq(instance->host_lock);

        return SUCCESS;
}