/*
 *  linux/drivers/acorn/scsi/acornscsi.c
 *
 *  Acorn SCSI 3 driver
 *  By R.M.King.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Abandoned using the Select and Transfer command since there were
 * some nasty races between our software and the target devices that
 * were not easy to solve, and the device errata had a lot of entries
 * for this command, some of them quite nasty...
 *
 * Changelog:
 *  26-Sep-1997 RMK     Re-jigged to use the queue module.
 *                      Re-coded state machine to be based on driver
 *                      state not scsi state.  Should be easier to debug.
 *                      Added acornscsi_release to clean up properly.
 *                      Updated proc/scsi reporting.
 *  05-Oct-1997 RMK     Implemented writing to SCSI devices.
 *  06-Oct-1997 RMK     Corrected small (non-serious) bug with the connect/
 *                      reconnect race condition causing a warning message.
 *  12-Oct-1997 RMK     Added catch for re-entering interrupt routine.
 *  15-Oct-1997 RMK     Improved handling of commands.
 *  27-Jun-1998 RMK     Changed asm/delay.h to linux/delay.h.
 *  13-Dec-1998 RMK     Better abort code and command handling.  Extra state
 *                      transitions added to allow dodgy devices to work.
 */
#define DEBUG_NO_WRITE  1
#define DEBUG_QUEUES    2
#define DEBUG_DMA       4
#define DEBUG_ABORT     8
#define DEBUG_DISCON    16
#define DEBUG_CONNECT   32
#define DEBUG_PHASES    64
#define DEBUG_WRITE     128
#define DEBUG_LINK      256
#define DEBUG_MESSAGES  512
#define DEBUG_RESET     1024
#define DEBUG_ALL       (DEBUG_RESET|DEBUG_MESSAGES|DEBUG_LINK|DEBUG_WRITE|\
                         DEBUG_PHASES|DEBUG_CONNECT|DEBUG_DISCON|DEBUG_ABORT|\
                         DEBUG_DMA|DEBUG_QUEUES)

/* DRIVER CONFIGURATION
 *
 * SCSI-II Tagged queue support.
 *
 * I don't have any SCSI devices that support it, so it is totally untested
 * (except to make sure that it doesn't interfere with any non-tagging
 * devices).  It is not fully implemented either - what happens when a
 * tagging device reconnects???
 *
 * You can tell if you have a device that supports tagged queueing my
 * cating (eg) /proc/scsi/acornscsi/0 and see if the SCSI revision is reported
 * as '2 TAG'.
 *
 * Also note that CONFIG_SCSI_ACORNSCSI_TAGGED_QUEUE is normally set in the config
 * scripts, but disabled here.  Once debugged, remove the #undef, otherwise to debug,
 * comment out the undef.
 */
#undef CONFIG_SCSI_ACORNSCSI_TAGGED_QUEUE
/*
 * SCSI-II Linked command support.
 *
 * The higher level code doesn't support linked commands yet, and so the option
 * is undef'd here.
 */
#undef CONFIG_SCSI_ACORNSCSI_LINK
/*
 * SCSI-II Synchronous transfer support.
 *
 * Tried and tested...
 *
 * SDTR_SIZE      - maximum number of un-acknowledged bytes (0 = off, 12 = max)
 * SDTR_PERIOD    - period of REQ signal (min=125, max=1020)
 * DEFAULT_PERIOD - default REQ period.
 */
#define SDTR_SIZE       12
#define SDTR_PERIOD     125
#define DEFAULT_PERIOD  500

/*
 * Debugging information
 *
 * DEBUG          - bit mask from list above
 * DEBUG_TARGET   - is defined to the target number if you want to debug
 *                  a specific target. [only recon/write/dma].
 */
#define DEBUG (DEBUG_RESET|DEBUG_WRITE|DEBUG_NO_WRITE)
/* only allow writing to SCSI device 0 */
#define NO_WRITE 0xFE
/*#define DEBUG_TARGET 2*/
/*
 * Select timeout time (in 10ms units)
 *
 * This is the timeout used between the start of selection and the WD33C93
 * chip deciding that the device isn't responding.
 */
#define TIMEOUT_TIME 10
/*
 * Define this if you want to have verbose explaination of SCSI
 * status/messages.
 */
#undef CONFIG_ACORNSCSI_CONSTANTS
/*
 * Define this if you want to use the on board DMAC [don't remove this option]
 * If not set, then use PIO mode (not currently supported).
 */
#define USE_DMAC

/*
 * ====================================================================================
 */

#ifdef DEBUG_TARGET
#define DBG(cmd,xxx...) \
  if (cmd->device->id == DEBUG_TARGET) { \
    xxx; \
  }
#else
#define DBG(cmd,xxx...) xxx
#endif

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/proc_fs.h>
#include <linux/ioport.h>
#include <linux/blkdev.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/bitops.h>
#include <linux/stringify.h>
#include <linux/io.h>

#include <asm/system.h>
#include <asm/ecard.h>

#include "../scsi.h"
#include <scsi/scsi_dbg.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_transport_spi.h>
#include "acornscsi.h"
#include "msgqueue.h"
#include "scsi.h"

#include <scsi/scsicam.h>

#define VER_MAJOR 2
#define VER_MINOR 0
#define VER_PATCH 6

#ifndef ABORT_TAG
#define ABORT_TAG 0xd
#else
#error "Yippee!  ABORT TAG is now defined!  Remove this error!"
#endif

#ifdef CONFIG_SCSI_ACORNSCSI_LINK
#error SCSI2 LINKed commands not supported (yet)!
#endif

#ifdef USE_DMAC
/*
 * DMAC setup parameters
 */ 
#define INIT_DEVCON0    (DEVCON0_RQL|DEVCON0_EXW|DEVCON0_CMP)
#define INIT_DEVCON1    (DEVCON1_BHLD)
#define DMAC_READ       (MODECON_READ)
#define DMAC_WRITE      (MODECON_WRITE)
#define INIT_SBICDMA    (CTRL_DMABURST)

#define scsi_xferred    have_data_in

/*
 * Size of on-board DMA buffer
 */
#define DMAC_BUFFER_SIZE        65536
#endif

#define STATUS_BUFFER_TO_PRINT  24

unsigned int sdtr_period = SDTR_PERIOD;
unsigned int sdtr_size   = SDTR_SIZE;

static void acornscsi_done(AS_Host *host, struct scsi_cmnd **SCpntp,
                           unsigned int result);
static int acornscsi_reconnect_finish(AS_Host *host);
static void acornscsi_dma_cleanup(AS_Host *host);
static void acornscsi_abortcmd(AS_Host *host, unsigned char tag);

/* ====================================================================================
 * Miscellaneous
 */

/* Offsets from MEMC base */
#define SBIC_REGIDX     0x2000
#define SBIC_REGVAL     0x2004
#define DMAC_OFFSET     0x3000

/* Offsets from FAST IOC base */
#define INT_REG         0x2000
#define PAGE_REG        0x3000

static inline void sbic_arm_write(AS_Host *host, unsigned int reg, unsigned int value)
{
    writeb(reg, host->base + SBIC_REGIDX);
    writeb(value, host->base + SBIC_REGVAL);
}

static inline int sbic_arm_read(AS_Host *host, unsigned int reg)
{
    if(reg == SBIC_ASR)
           return readl(host->base + SBIC_REGIDX) & 255;
    writeb(reg, host->base + SBIC_REGIDX);
    return readl(host->base + SBIC_REGVAL) & 255;
}

#define sbic_arm_writenext(host, val)   writeb((val), (host)->base + SBIC_REGVAL)
#define sbic_arm_readnext(host)         readb((host)->base + SBIC_REGVAL)

#ifdef USE_DMAC
#define dmac_read(host,reg) \
        readb((host)->base + DMAC_OFFSET + ((reg) << 2))

#define dmac_write(host,reg,value) \
        ({ writeb((value), (host)->base + DMAC_OFFSET + ((reg) << 2)); })

#define dmac_clearintr(host)    writeb(0, (host)->fast + INT_REG)

static inline unsigned int dmac_address(AS_Host *host)
{
    return dmac_read(host, DMAC_TXADRHI) << 16 |
           dmac_read(host, DMAC_TXADRMD) << 8 |
           dmac_read(host, DMAC_TXADRLO);
}

static
void acornscsi_dumpdma(AS_Host *host, char *where)
{
        unsigned int mode, addr, len;

        mode = dmac_read(host, DMAC_MODECON);
        addr = dmac_address(host);
        len  = dmac_read(host, DMAC_TXCNTHI) << 8 |
               dmac_read(host, DMAC_TXCNTLO);

        printk("scsi%d: %s: DMAC %02x @%06x+%04x msk %02x, ",
                host->host->host_no, where,
                mode, addr, (len + 1) & 0xffff,
                dmac_read(host, DMAC_MASKREG));

        printk("DMA @%06x, ", host->dma.start_addr);
        printk("BH @%p +%04x, ", host->scsi.SCp.ptr,
                host->scsi.SCp.this_residual);
        printk("DT @+%04x ST @+%04x", host->dma.transferred,
                host->scsi.SCp.scsi_xferred);
        printk("\n");
}
#endif

static
unsigned long acornscsi_sbic_xfcount(AS_Host *host)
{
    unsigned long length;

    length = sbic_arm_read(host, SBIC_TRANSCNTH) << 16;
    length |= sbic_arm_readnext(host) << 8;
    length |= sbic_arm_readnext(host);

    return length;
}

static int
acornscsi_sbic_wait(AS_Host *host, int stat_mask, int stat, int timeout, char *msg)
{
        int asr;

        do {
                asr = sbic_arm_read(host, SBIC_ASR);

                if ((asr & stat_mask) == stat)
                        return 0;

                udelay(1);
        } while (--timeout);

        printk("scsi%d: timeout while %s\n", host->host->host_no, msg);

        return -1;
}

static
int acornscsi_sbic_issuecmd(AS_Host *host, int command)
{
    if (acornscsi_sbic_wait(host, ASR_CIP, 0, 1000, "issuing command"))
        return -1;

    sbic_arm_write(host, SBIC_CMND, command);

    return 0;
}

static void
acornscsi_csdelay(unsigned int cs)
{
    unsigned long target_jiffies, flags;

    target_jiffies = jiffies + 1 + cs * HZ / 100;

    local_save_flags(flags);
    local_irq_enable();

    while (time_before(jiffies, target_jiffies)) barrier();

    local_irq_restore(flags);
}

static
void acornscsi_resetcard(AS_Host *host)
{
    unsigned int i, timeout;

    /* assert reset line */
    host->card.page_reg = 0x80;
    writeb(host->card.page_reg, host->fast + PAGE_REG);

    /* wait 3 cs.  SCSI standard says 25ms. */
    acornscsi_csdelay(3);

    host->card.page_reg = 0;
    writeb(host->card.page_reg, host->fast + PAGE_REG);

    /*
     * Should get a reset from the card
     */
    timeout = 1000;
    do {
        if (readb(host->fast + INT_REG) & 8)
            break;
        udelay(1);
    } while (--timeout);

    if (timeout == 0)
        printk("scsi%d: timeout while resetting card\n",
                host->host->host_no);

    sbic_arm_read(host, SBIC_ASR);
    sbic_arm_read(host, SBIC_SSR);

    /* setup sbic - WD33C93A */
    sbic_arm_write(host, SBIC_OWNID, OWNID_EAF | host->host->this_id);
    sbic_arm_write(host, SBIC_CMND, CMND_RESET);

    /*
     * Command should cause a reset interrupt
     */
    timeout = 1000;
    do {
        if (readb(host->fast + INT_REG) & 8)
            break;
        udelay(1);
    } while (--timeout);

    if (timeout == 0)
        printk("scsi%d: timeout while resetting card\n",
                host->host->host_no);

    sbic_arm_read(host, SBIC_ASR);
    if (sbic_arm_read(host, SBIC_SSR) != 0x01)
        printk(KERN_CRIT "scsi%d: WD33C93A didn't give enhanced reset interrupt\n",
                host->host->host_no);

    sbic_arm_write(host, SBIC_CTRL, INIT_SBICDMA | CTRL_IDI);
    sbic_arm_write(host, SBIC_TIMEOUT, TIMEOUT_TIME);
    sbic_arm_write(host, SBIC_SYNCHTRANSFER, SYNCHTRANSFER_2DBA);
    sbic_arm_write(host, SBIC_SOURCEID, SOURCEID_ER | SOURCEID_DSP);

    host->card.page_reg = 0x40;
    writeb(host->card.page_reg, host->fast + PAGE_REG);

    /* setup dmac - uPC71071 */
    dmac_write(host, DMAC_INIT, 0);
#ifdef USE_DMAC
    dmac_write(host, DMAC_INIT, INIT_8BIT);
    dmac_write(host, DMAC_CHANNEL, CHANNEL_0);
    dmac_write(host, DMAC_DEVCON0, INIT_DEVCON0);
    dmac_write(host, DMAC_DEVCON1, INIT_DEVCON1);
#endif

    host->SCpnt = NULL;
    host->scsi.phase = PHASE_IDLE;
    host->scsi.disconnectable = 0;

    memset(host->busyluns, 0, sizeof(host->busyluns));

    for (i = 0; i < 8; i++) {
        host->device[i].sync_state = SYNC_NEGOCIATE;
        host->device[i].disconnect_ok = 1;
    }

    /* wait 25 cs.  SCSI standard says 250ms. */
    acornscsi_csdelay(25);
}

/*=============================================================================================
 * Utility routines (eg. debug)
 */
#ifdef CONFIG_ACORNSCSI_CONSTANTS
static char *acornscsi_interrupttype[] = {
  "rst",  "suc",  "p/a",  "3",
  "term", "5",    "6",    "7",
  "serv", "9",    "a",    "b",
  "c",    "d",    "e",    "f"
};

static signed char acornscsi_map[] = {
  0,  1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1,
 -1,  2, -1, -1,  -1, -1,  3, -1,   4,  5,  6,  7,   8,  9, 10, 11,
 12, 13, 14, -1,  -1, -1, -1, -1,   4,  5,  6,  7,   8,  9, 10, 11,
 -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1,
 15, 16, 17, 18,  19, -1, -1, 20,   4,  5,  6,  7,   8,  9, 10, 11,
 -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1,
 -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1,
 -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1,
 21, 22, -1, -1,  -1, 23, -1, -1,   4,  5,  6,  7,   8,  9, 10, 11,
 -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1,
 -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1,
 -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1,
 -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1,
 -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1,
 -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1,
 -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1,  -1, -1, -1, -1
};      

static char *acornscsi_interruptcode[] = {
    /* 0 */
    "reset - normal mode",      /* 00 */
    "reset - advanced mode",    /* 01 */

    /* 2 */
    "sel",                      /* 11 */
    "sel+xfer",                 /* 16 */
    "data-out",                 /* 18 */
    "data-in",                  /* 19 */
    "cmd",                      /* 1A */
    "stat",                     /* 1B */
    "??-out",                   /* 1C */
    "??-in",                    /* 1D */
    "msg-out",                  /* 1E */
    "msg-in",                   /* 1F */

    /* 12 */
    "/ACK asserted",            /* 20 */
    "save-data-ptr",            /* 21 */
    "{re}sel",                  /* 22 */

    /* 15 */
    "inv cmd",                  /* 40 */
    "unexpected disconnect",    /* 41 */
    "sel timeout",              /* 42 */
    "P err",                    /* 43 */
    "P err+ATN",                /* 44 */
    "bad status byte",          /* 47 */

    /* 21 */
    "resel, no id",             /* 80 */
    "resel",                    /* 81 */
    "discon",                   /* 85 */
};

static
void print_scsi_status(unsigned int ssr)
{
    if (acornscsi_map[ssr] != -1)
        printk("%s:%s",
                acornscsi_interrupttype[(ssr >> 4)],
                acornscsi_interruptcode[acornscsi_map[ssr]]);
    else
        printk("%X:%X", ssr >> 4, ssr & 0x0f);    
}    
#endif

static
void print_sbic_status(int asr, int ssr, int cmdphase)
{
#ifdef CONFIG_ACORNSCSI_CONSTANTS
    printk("sbic: %c%c%c%c%c%c ",
            asr & ASR_INT ? 'I' : 'i',
            asr & ASR_LCI ? 'L' : 'l',
            asr & ASR_BSY ? 'B' : 'b',
            asr & ASR_CIP ? 'C' : 'c',
            asr & ASR_PE  ? 'P' : 'p',
            asr & ASR_DBR ? 'D' : 'd');
    printk("scsi: ");
    print_scsi_status(ssr);
    printk(" ph %02X\n", cmdphase);
#else
    printk("sbic: %02X scsi: %X:%X ph: %02X\n",
            asr, (ssr & 0xf0)>>4, ssr & 0x0f, cmdphase);
#endif
}

static void
acornscsi_dumplogline(AS_Host *host, int target, int line)
{
        unsigned long prev;
        signed int ptr;

        ptr = host->status_ptr[target] - STATUS_BUFFER_TO_PRINT;
        if (ptr < 0)
                ptr += STATUS_BUFFER_SIZE;

        printk("%c: %3s:", target == 8 ? 'H' : '0' + target,
                line == 0 ? "ph" : line == 1 ? "ssr" : "int");

        prev = host->status[target][ptr].when;

        for (; ptr != host->status_ptr[target]; ptr = (ptr + 1) & (STATUS_BUFFER_SIZE - 1)) {
                unsigned long time_diff;

                if (!host->status[target][ptr].when)
                        continue;

                switch (line) {
                case 0:
                        printk("%c%02X", host->status[target][ptr].irq ? '-' : ' ',
                                         host->status[target][ptr].ph);
                        break;

                case 1:
                        printk(" %02X", host->status[target][ptr].ssr);
                        break;

                case 2:
                        time_diff = host->status[target][ptr].when - prev;
                        prev = host->status[target][ptr].when;
                        if (time_diff == 0)
                                printk("==^");
                        else if (time_diff >= 100)
                                printk("   ");
                        else
                                printk(" %02ld", time_diff);
                        break;
                }
        }

        printk("\n");
}

static
void acornscsi_dumplog(AS_Host *host, int target)
{
    do {
        acornscsi_dumplogline(host, target, 0);
        acornscsi_dumplogline(host, target, 1);
        acornscsi_dumplogline(host, target, 2);

        if (target == 8)
            break;

        target = 8;
    } while (1);
}

static
char acornscsi_target(AS_Host *host)
{
        if (host->SCpnt)
                return '0' + host->SCpnt->device->id;
        return 'H';
}

/*
 * Prototype: cmdtype_t acornscsi_cmdtype(int command)
 * Purpose  : differentiate READ from WRITE from other commands
 * Params   : command - command to interpret
 * Returns  : CMD_READ  - command reads data,
 *            CMD_WRITE - command writes data,
 *            CMD_MISC  - everything else
 */
static inline
cmdtype_t acornscsi_cmdtype(int command)
{
    switch (command) {
    case WRITE_6:  case WRITE_10:  case WRITE_12:
        return CMD_WRITE;
    case READ_6:   case READ_10:   case READ_12:
        return CMD_READ;
    default:
        return CMD_MISC;
    }
}

/*
 * Prototype: int acornscsi_datadirection(int command)
 * Purpose  : differentiate between commands that have a DATA IN phase
 *            and a DATA OUT phase
 * Params   : command - command to interpret
 * Returns  : DATADIR_OUT - data out phase expected
 *            DATADIR_IN  - data in phase expected
 */
static
datadir_t acornscsi_datadirection(int command)
{
    switch (command) {
    case CHANGE_DEFINITION:     case COMPARE:           case COPY:
    case COPY_VERIFY:           case LOG_SELECT:        case MODE_SELECT:
    case MODE_SELECT_10:        case SEND_DIAGNOSTIC:   case WRITE_BUFFER:
    case FORMAT_UNIT:           case REASSIGN_BLOCKS:   case RESERVE:
    case SEARCH_EQUAL:          case SEARCH_HIGH:       case SEARCH_LOW:
    case WRITE_6:               case WRITE_10:          case WRITE_VERIFY:
    case UPDATE_BLOCK:          case WRITE_LONG:        case WRITE_SAME:
    case SEARCH_HIGH_12:        case SEARCH_EQUAL_12:   case SEARCH_LOW_12:
    case WRITE_12:              case WRITE_VERIFY_12:   case SET_WINDOW:
    case MEDIUM_SCAN:           case SEND_VOLUME_TAG:   case 0xea:
        return DATADIR_OUT;
    default:
        return DATADIR_IN;
    }
}

/*
 * Purpose  : provide values for synchronous transfers with 33C93.
 * Copyright: Copyright (c) 1996 John Shifflett, GeoLog Consulting
 *      Modified by Russell King for 8MHz WD33C93A
 */
static struct sync_xfer_tbl {
    unsigned int period_ns;
    unsigned char reg_value;
} sync_xfer_table[] = {
    {   1, 0x20 },    { 249, 0x20 },    { 374, 0x30 },
    { 499, 0x40 },    { 624, 0x50 },    { 749, 0x60 },
    { 874, 0x70 },    { 999, 0x00 },    {   0,    0 }
};

/*
 * Prototype: int acornscsi_getperiod(unsigned char syncxfer)
 * Purpose  : period for the synchronous transfer setting
 * Params   : syncxfer SYNCXFER register value
 * Returns  : period in ns.
 */
static
int acornscsi_getperiod(unsigned char syncxfer)
{
    int i;

    syncxfer &= 0xf0;
    if (syncxfer == 0x10)
        syncxfer = 0;

    for (i = 1; sync_xfer_table[i].period_ns; i++)
        if (syncxfer == sync_xfer_table[i].reg_value)
            return sync_xfer_table[i].period_ns;
    return 0;
}

/*
 * Prototype: int round_period(unsigned int period)
 * Purpose  : return index into above table for a required REQ period
 * Params   : period - time (ns) for REQ
 * Returns  : table index
 * Copyright: Copyright (c) 1996 John Shifflett, GeoLog Consulting
 */
static inline
int round_period(unsigned int period)
{
    int i;

    for (i = 1; sync_xfer_table[i].period_ns; i++) {
        if ((period <= sync_xfer_table[i].period_ns) &&
            (period > sync_xfer_table[i - 1].period_ns))
            return i;
    }
    return 7;
}

/*
 * Prototype: unsigned char calc_sync_xfer(unsigned int period, unsigned int offset)
 * Purpose  : calculate value for 33c93s SYNC register
 * Params   : period - time (ns) for REQ
 *            offset - offset in bytes between REQ/ACK
 * Returns  : value for SYNC register
 * Copyright: Copyright (c) 1996 John Shifflett, GeoLog Consulting
 */
static
unsigned char calc_sync_xfer(unsigned int period, unsigned int offset)
{
    return sync_xfer_table[round_period(period)].reg_value |
                ((offset < SDTR_SIZE) ? offset : SDTR_SIZE);
}

/* ====================================================================================
 * Command functions
 */
/*
 * Function: acornscsi_kick(AS_Host *host)
 * Purpose : kick next command to interface
 * Params  : host - host to send command to
 * Returns : INTR_IDLE if idle, otherwise INTR_PROCESSING
 * Notes   : interrupts are always disabled!
 */
static
intr_ret_t acornscsi_kick(AS_Host *host)
{
    int from_queue = 0;
    struct scsi_cmnd *SCpnt;

    /* first check to see if a command is waiting to be executed */
    SCpnt = host->origSCpnt;
    host->origSCpnt = NULL;

    /* retrieve next command */
    if (!SCpnt) {
        SCpnt = queue_remove_exclude(&host->queues.issue, host->busyluns);
        if (!SCpnt)
            return INTR_IDLE;

        from_queue = 1;
    }

    if (host->scsi.disconnectable && host->SCpnt) {
        queue_add_cmd_tail(&host->queues.disconnected, host->SCpnt);
        host->scsi.disconnectable = 0;
#if (DEBUG & (DEBUG_QUEUES|DEBUG_DISCON))
        DBG(host->SCpnt, printk("scsi%d.%c: moved command to disconnected queue\n",
                host->host->host_no, acornscsi_target(host)));
#endif
        host->SCpnt = NULL;
    }

    /*
     * If we have an interrupt pending, then we may have been reselected.
     * In this case, we don't want to write to the registers
     */
    if (!(sbic_arm_read(host, SBIC_ASR) & (ASR_INT|ASR_BSY|ASR_CIP))) {
        sbic_arm_write(host, SBIC_DESTID, SCpnt->device->id);
        sbic_arm_write(host, SBIC_CMND, CMND_SELWITHATN);
    }

    /*
     * claim host busy - all of these must happen atomically wrt
     * our interrupt routine.  Failure means command loss.
     */
    host->scsi.phase = PHASE_CONNECTING;
    host->SCpnt = SCpnt;
    host->scsi.SCp = SCpnt->SCp;
    host->dma.xfer_setup = 0;
    host->dma.xfer_required = 0;
    host->dma.xfer_done = 0;

#if (DEBUG & (DEBUG_ABORT|DEBUG_CONNECT))
    DBG(SCpnt,printk("scsi%d.%c: starting cmd %02X\n",
            host->host->host_no, '0' + SCpnt->device->id,
            SCpnt->cmnd[0]));
#endif

    if (from_queue) {
#ifdef CONFIG_SCSI_ACORNSCSI_TAGGED_QUEUE
        /*
         * tagged queueing - allocate a new tag to this command
         */
        if (SCpnt->device->simple_tags) {
            SCpnt->device->current_tag += 1;
            if (SCpnt->device->current_tag == 0)
                SCpnt->device->current_tag = 1;
            SCpnt->tag = SCpnt->device->current_tag;
        } else
#endif
            set_bit(SCpnt->device->id * 8 + SCpnt->device->lun, host->busyluns);

        host->stats.removes += 1;

        switch (acornscsi_cmdtype(SCpnt->cmnd[0])) {
        case CMD_WRITE:
            host->stats.writes += 1;
            break;
        case CMD_READ:
            host->stats.reads += 1;
            break;
        case CMD_MISC:
            host->stats.miscs += 1;
            break;
        }
    }

    return INTR_PROCESSING;
}    

/*
 * Function: void acornscsi_done(AS_Host *host, struct scsi_cmnd **SCpntp, unsigned int result)
 * Purpose : complete processing for command
 * Params  : host   - interface that completed
 *           result - driver byte of result
 */
static void acornscsi_done(AS_Host *host, struct scsi_cmnd **SCpntp,
                           unsigned int result)
{
        struct scsi_cmnd *SCpnt = *SCpntp;

    /* clean up */
    sbic_arm_write(host, SBIC_SOURCEID, SOURCEID_ER | SOURCEID_DSP);

    host->stats.fins += 1;

    if (SCpnt) {
        *SCpntp = NULL;

        acornscsi_dma_cleanup(host);

        SCpnt->result = result << 16 | host->scsi.SCp.Message << 8 | host->scsi.SCp.Status;

        /*
         * In theory, this should not happen.  In practice, it seems to.
         * Only trigger an error if the device attempts to report all happy
         * but with untransferred buffers...  If we don't do something, then
         * data loss will occur.  Should we check SCpnt->underflow here?
         * It doesn't appear to be set to something meaningful by the higher
         * levels all the time.
         */
        if (result == DID_OK) {
                int xfer_warn = 0;

                if (SCpnt->underflow == 0) {
                        if (host->scsi.SCp.ptr &&
                            acornscsi_cmdtype(SCpnt->cmnd[0]) != CMD_MISC)
                                xfer_warn = 1;
                } else {
                        if (host->scsi.SCp.scsi_xferred < SCpnt->underflow ||
                            host->scsi.SCp.scsi_xferred != host->dma.transferred)
                                xfer_warn = 1;
                }

                /* ANSI standard says: (SCSI-2 Rev 10c Sect 5.6.6)
                 *  Targets which break data transfers into multiple
                 *  connections shall end each successful connection
                 *  (except possibly the last) with a SAVE DATA
                 *  POINTER - DISCONNECT message sequence.
                 *
                 * This makes it difficult to ensure that a transfer has
                 * completed.  If we reach the end of a transfer during
                 * the command, then we can only have finished the transfer.
                 * therefore, if we seem to have some data remaining, this
                 * is not a problem.
                 */
                if (host->dma.xfer_done)
                        xfer_warn = 0;

                if (xfer_warn) {
                    switch (status_byte(SCpnt->result)) {
                    case CHECK_CONDITION:
                    case COMMAND_TERMINATED:
                    case BUSY:
                    case QUEUE_FULL:
                    case RESERVATION_CONFLICT:
                        break;

                    default:
                        printk(KERN_ERR "scsi%d.H: incomplete data transfer detected: result=%08X command=",
                                host->host->host_no, SCpnt->result);
                        __scsi_print_command(SCpnt->cmnd);
                        acornscsi_dumpdma(host, "done");
                        acornscsi_dumplog(host, SCpnt->device->id);
                        SCpnt->result &= 0xffff;
                        SCpnt->result |= DID_ERROR << 16;
                    }
                }
        }

        if (!SCpnt->scsi_done)
            panic("scsi%d.H: null scsi_done function in acornscsi_done", host->host->host_no);

        clear_bit(SCpnt->device->id * 8 + SCpnt->device->lun, host->busyluns);

        SCpnt->scsi_done(SCpnt);
    } else
        printk("scsi%d: null command in acornscsi_done", host->host->host_no);

    host->scsi.phase = PHASE_IDLE;
}

/* ====================================================================================
 * DMA routines
 */
/*
 * Purpose  : update SCSI Data Pointer
 * Notes    : this will only be one SG entry or less
 */
static
void acornscsi_data_updateptr(AS_Host *host, struct scsi_pointer *SCp, unsigned int length)
{
    SCp->ptr += length;
    SCp->this_residual -= length;

    if (SCp->this_residual == 0 && next_SCp(SCp) == 0)
        host->dma.xfer_done = 1;
}

/*
 * Prototype: void acornscsi_data_read(AS_Host *host, char *ptr,
 *                              unsigned int start_addr, unsigned int length)
 * Purpose  : read data from DMA RAM
 * Params   : host - host to transfer from
 *            ptr  - DRAM address
 *            start_addr - host mem address
 *            length - number of bytes to transfer
 * Notes    : this will only be one SG entry or less
 */
static
void acornscsi_data_read(AS_Host *host, char *ptr,
                                 unsigned int start_addr, unsigned int length)
{
    extern void __acornscsi_in(void __iomem *, char *buf, int len);
    unsigned int page, offset, len = length;

    page = (start_addr >> 12);
    offset = start_addr & ((1 << 12) - 1);

    writeb((page & 0x3f) | host->card.page_reg, host->fast + PAGE_REG);

    while (len > 0) {
        unsigned int this_len;

        if (len + offset > (1 << 12))
            this_len = (1 << 12) - offset;
        else
            this_len = len;

        __acornscsi_in(host->base + (offset << 1), ptr, this_len);

        offset += this_len;
        ptr += this_len;
        len -= this_len;

        if (offset == (1 << 12)) {
            offset = 0;
            page ++;
            writeb((page & 0x3f) | host->card.page_reg, host->fast + PAGE_REG);
        }
    }
    writeb(host->card.page_reg, host->fast + PAGE_REG);
}

/*
 * Prototype: void acornscsi_data_write(AS_Host *host, char *ptr,
 *                              unsigned int start_addr, unsigned int length)
 * Purpose  : write data to DMA RAM
 * Params   : host - host to transfer from
 *            ptr  - DRAM address
 *            start_addr - host mem address
 *            length - number of bytes to transfer
 * Notes    : this will only be one SG entry or less
 */
static
void acornscsi_data_write(AS_Host *host, char *ptr,
                                 unsigned int start_addr, unsigned int length)
{
    extern void __acornscsi_out(void __iomem *, char *buf, int len);
    unsigned int page, offset, len = length;

    page = (start_addr >> 12);
    offset = start_addr & ((1 << 12) - 1);

    writeb((page & 0x3f) | host->card.page_reg, host->fast + PAGE_REG);

    while (len > 0) {
        unsigned int this_len;

        if (len + offset > (1 << 12))
            this_len = (1 << 12) - offset;
        else
            this_len = len;

        __acornscsi_out(host->base + (offset << 1), ptr, this_len);

        offset += this_len;
        ptr += this_len;
        len -= this_len;

        if (offset == (1 << 12)) {
            offset = 0;
            page ++;
            writeb((page & 0x3f) | host->card.page_reg, host->fast + PAGE_REG);
        }
    }
    writeb(host->card.page_reg, host->fast + PAGE_REG);
}

/* =========================================================================================
 * On-board DMA routines
 */
#ifdef USE_DMAC
/*
 * Prototype: void acornscsi_dmastop(AS_Host *host)
 * Purpose  : stop all DMA

 * Params   : host - host on which to stop DMA
 * Notes    : This is called when leaving DATA IN/OUT phase,
 *            or when interface is RESET
 */
static inline
void acornscsi_dma_stop(AS_Host *host)
{
    dmac_write(host, DMAC_MASKREG, MASK_ON);
    dmac_clearintr(host);

#if (DEBUG & DEBUG_DMA)
    DBG(host->SCpnt, acornscsi_dumpdma(host, "stop"));
#endif
}

/*
 * Function: void acornscsi_dma_setup(AS_Host *host, dmadir_t direction)
 * Purpose : setup DMA controller for data transfer
 * Params  : host - host to setup
 *           direction - data transfer direction
 * Notes   : This is called when entering DATA I/O phase, not
 *           while we're in a DATA I/O phase
 */
static
void acornscsi_dma_setup(AS_Host *host, dmadir_t direction)
{
    unsigned int address, length, mode;

    host->dma.direction = direction;

    dmac_write(host, DMAC_MASKREG, MASK_ON);

    if (direction == DMA_OUT) {
#if (DEBUG & DEBUG_NO_WRITE)
        if (NO_WRITE & (1 << host->SCpnt->device->id)) {
            printk(KERN_CRIT "scsi%d.%c: I can't handle DMA_OUT!\n",
                    host->host->host_no, acornscsi_target(host));
            return;
        }
#endif
        mode = DMAC_WRITE;
    } else
        mode = DMAC_READ;

    /*
     * Allocate some buffer space, limited to half the buffer size
     */
    length = min_t(unsigned int, host->scsi.SCp.this_residual, DMAC_BUFFER_SIZE / 2);
    if (length) {
        host->dma.start_addr = address = host->dma.free_addr;
        host->dma.free_addr = (host->dma.free_addr + length) &
                                (DMAC_BUFFER_SIZE - 1);

        /*
         * Transfer data to DMA memory
         */
        if (direction == DMA_OUT)
            acornscsi_data_write(host, host->scsi.SCp.ptr, host->dma.start_addr,
                                length);

        length -= 1;
        dmac_write(host, DMAC_TXCNTLO, length);
        dmac_write(host, DMAC_TXCNTHI, length >> 8);
        dmac_write(host, DMAC_TXADRLO, address);
        dmac_write(host, DMAC_TXADRMD, address >> 8);
        dmac_write(host, DMAC_TXADRHI, 0);
        dmac_write(host, DMAC_MODECON, mode);
        dmac_write(host, DMAC_MASKREG, MASK_OFF);

#if (DEBUG & DEBUG_DMA)
        DBG(host->SCpnt, acornscsi_dumpdma(host, "strt"));
#endif
        host->dma.xfer_setup = 1;
    }
}

/*
 * Function: void acornscsi_dma_cleanup(AS_Host *host)
 * Purpose : ensure that all DMA transfers are up-to-date & host->scsi.SCp is correct
 * Params  : host - host to finish
 * Notes   : This is called when a command is:
 *              terminating, RESTORE_POINTERS, SAVE_POINTERS, DISCONECT
 *         : This must not return until all transfers are completed.
 */
static
void acornscsi_dma_cleanup(AS_Host *host)
{
    dmac_write(host, DMAC_MASKREG, MASK_ON);
    dmac_clearintr(host);

    /*
     * Check for a pending transfer
     */
    if (host->dma.xfer_required) {
        host->dma.xfer_required = 0;
        if (host->dma.direction == DMA_IN)
            acornscsi_data_read(host, host->dma.xfer_ptr,
                                 host->dma.xfer_start, host->dma.xfer_length);
    }

    /*
     * Has a transfer been setup?
     */
    if (host->dma.xfer_setup) {
        unsigned int transferred;

        host->dma.xfer_setup = 0;

#if (DEBUG & DEBUG_DMA)
        DBG(host->SCpnt, acornscsi_dumpdma(host, "cupi"));
#endif

        /*
         * Calculate number of bytes transferred from DMA.
         */
        transferred = dmac_address(host) - host->dma.start_addr;
        host->dma.transferred += transferred;

        if (host->dma.direction == DMA_IN)
            acornscsi_data_read(host, host->scsi.SCp.ptr,
                                 host->dma.start_addr, transferred);

        /*
         * Update SCSI pointers
         */
        acornscsi_data_updateptr(host, &host->scsi.SCp, transferred);
#if (DEBUG & DEBUG_DMA)
        DBG(host->SCpnt, acornscsi_dumpdma(host, "cupo"));
#endif
    }
}

/*
 * Function: void acornscsi_dmacintr(AS_Host *host)
 * Purpose : handle interrupts from DMAC device
 * Params  : host - host to process
 * Notes   : If reading, we schedule the read to main memory &
 *           allow the transfer to continue.
 *         : If writing, we fill the onboard DMA memory from main
 *           memory.
 *         : Called whenever DMAC finished it's current transfer.
 */
static
void acornscsi_dma_intr(AS_Host *host)
{
    unsigned int address, length, transferred;

#if (DEBUG & DEBUG_DMA)
    DBG(host->SCpnt, acornscsi_dumpdma(host, "inti"));
#endif

    dmac_write(host, DMAC_MASKREG, MASK_ON);
    dmac_clearintr(host);

    /*
     * Calculate amount transferred via DMA
     */
    transferred = dmac_address(host) - host->dma.start_addr;
    host->dma.transferred += transferred;

    /*
     * Schedule DMA transfer off board
     */
    if (host->dma.direction == DMA_IN) {
        host->dma.xfer_start = host->dma.start_addr;
        host->dma.xfer_length = transferred;
        host->dma.xfer_ptr = host->scsi.SCp.ptr;
        host->dma.xfer_required = 1;
    }

    acornscsi_data_updateptr(host, &host->scsi.SCp, transferred);

    /*
     * Allocate some buffer space, limited to half the on-board RAM size
     */
    length = min_t(unsigned int, host->scsi.SCp.this_residual, DMAC_BUFFER_SIZE / 2);
    if (length) {
        host->dma.start_addr = address = host->dma.free_addr;
        host->dma.free_addr = (host->dma.free_addr + length) &
                                (DMAC_BUFFER_SIZE - 1);

        /*
         * Transfer data to DMA memory
         */
        if (host->dma.direction == DMA_OUT)
            acornscsi_data_write(host, host->scsi.SCp.ptr, host->dma.start_addr,
                                length);

        length -= 1;
        dmac_write(host, DMAC_TXCNTLO, length);
        dmac_write(host, DMAC_TXCNTHI, length >> 8);
        dmac_write(host, DMAC_TXADRLO, address);
        dmac_write(host, DMAC_TXADRMD, address >> 8);
        dmac_write(host, DMAC_TXADRHI, 0);
        dmac_write(host, DMAC_MASKREG, MASK_OFF);

#if (DEBUG & DEBUG_DMA)
        DBG(host->SCpnt, acornscsi_dumpdma(host, "into"));
#endif
    } else {
        host->dma.xfer_setup = 0;
#if 0
        /*
         * If the interface still wants more, then this is an error.
         * We give it another byte, but we also attempt to raise an
         * attention condition.  We continue giving one byte until
         * the device recognises the attention.
         */
        if (dmac_read(host, DMAC_STATUS) & STATUS_RQ0) {
            acornscsi_abortcmd(host, host->SCpnt->tag);

            dmac_write(host, DMAC_TXCNTLO, 0);
            dmac_write(host, DMAC_TXCNTHI, 0);
            dmac_write(host, DMAC_TXADRLO, 0);
            dmac_write(host, DMAC_TXADRMD, 0);
            dmac_write(host, DMAC_TXADRHI, 0);
            dmac_write(host, DMAC_MASKREG, MASK_OFF);
        }
#endif
    }
}

/*
 * Function: void acornscsi_dma_xfer(AS_Host *host)
 * Purpose : transfer data between AcornSCSI and memory
 * Params  : host - host to process
 */
static
void acornscsi_dma_xfer(AS_Host *host)
{
    host->dma.xfer_required = 0;

    if (host->dma.direction == DMA_IN)
        acornscsi_data_read(host, host->dma.xfer_ptr,
                                host->dma.xfer_start, host->dma.xfer_length);
}

/*
 * Function: void acornscsi_dma_adjust(AS_Host *host)
 * Purpose : adjust DMA pointers & count for bytes transferred to
 *           SBIC but not SCSI bus.
 * Params  : host - host to adjust DMA count for
 */
static
void acornscsi_dma_adjust(AS_Host *host)
{
    if (host->dma.xfer_setup) {
        signed long transferred;
#if (DEBUG & (DEBUG_DMA|DEBUG_WRITE))
        DBG(host->SCpnt, acornscsi_dumpdma(host, "adji"));
#endif
        /*
         * Calculate correct DMA address - DMA is ahead of SCSI bus while
         * writing.
         *  host->scsi.SCp.scsi_xferred is the number of bytes
         *  actually transferred to/from the SCSI bus.
         *  host->dma.transferred is the number of bytes transferred
         *  over DMA since host->dma.start_addr was last set.
         *
         * real_dma_addr = host->dma.start_addr + host->scsi.SCp.scsi_xferred
         *                 - host->dma.transferred
         */
        transferred = host->scsi.SCp.scsi_xferred - host->dma.transferred;
        if (transferred < 0)
            printk("scsi%d.%c: Ack! DMA write correction %ld < 0!\n",
                    host->host->host_no, acornscsi_target(host), transferred);
        else if (transferred == 0)
            host->dma.xfer_setup = 0;
        else {
            transferred += host->dma.start_addr;
            dmac_write(host, DMAC_TXADRLO, transferred);
            dmac_write(host, DMAC_TXADRMD, transferred >> 8);
            dmac_write(host, DMAC_TXADRHI, transferred >> 16);
#if (DEBUG & (DEBUG_DMA|DEBUG_WRITE))
            DBG(host->SCpnt, acornscsi_dumpdma(host, "adjo"));
#endif
        }
    }
}
#endif

/* =========================================================================================
 * Data I/O
 */
static int
acornscsi_write_pio(AS_Host *host, char *bytes, int *ptr, int len, unsigned int max_timeout)
{
        unsigned int asr, timeout = max_timeout;
        int my_ptr = *ptr;

        while (my_ptr < len) {
                asr = sbic_arm_read(host, SBIC_ASR);

                if (asr & ASR_DBR) {
                        timeout = max_timeout;

                        sbic_arm_write(host, SBIC_DATA, bytes[my_ptr++]);
                } else if (asr & ASR_INT)
                        break;
                else if (--timeout == 0)
                        break;
                udelay(1);
        }

        *ptr = my_ptr;

        return (timeout == 0) ? -1 : 0;
}

/*
 * Function: void acornscsi_sendcommand(AS_Host *host)
 * Purpose : send a command to a target
 * Params  : host - host which is connected to target
 */
static void
acornscsi_sendcommand(AS_Host *host)
{
        struct scsi_cmnd *SCpnt = host->SCpnt;

    sbic_arm_write(host, SBIC_TRANSCNTH, 0);
    sbic_arm_writenext(host, 0);
    sbic_arm_writenext(host, SCpnt->cmd_len - host->scsi.SCp.sent_command);

    acornscsi_sbic_issuecmd(host, CMND_XFERINFO);

    if (acornscsi_write_pio(host, SCpnt->cmnd,
        (int *)&host->scsi.SCp.sent_command, SCpnt->cmd_len, 1000000))
        printk("scsi%d: timeout while sending command\n", host->host->host_no);

    host->scsi.phase = PHASE_COMMAND;
}

static
void acornscsi_sendmessage(AS_Host *host)
{
    unsigned int message_length = msgqueue_msglength(&host->scsi.msgs);
    unsigned int msgnr;
    struct message *msg;

#if (DEBUG & DEBUG_MESSAGES)
    printk("scsi%d.%c: sending message ",
            host->host->host_no, acornscsi_target(host));
#endif

    switch (message_length) {
    case 0:
        acornscsi_sbic_issuecmd(host, CMND_XFERINFO | CMND_SBT);

        acornscsi_sbic_wait(host, ASR_DBR, ASR_DBR, 1000, "sending message 1");

        sbic_arm_write(host, SBIC_DATA, NOP);

        host->scsi.last_message = NOP;
#if (DEBUG & DEBUG_MESSAGES)
        printk("NOP");
#endif
        break;

    case 1:
        acornscsi_sbic_issuecmd(host, CMND_XFERINFO | CMND_SBT);
        msg = msgqueue_getmsg(&host->scsi.msgs, 0);

        acornscsi_sbic_wait(host, ASR_DBR, ASR_DBR, 1000, "sending message 2");

        sbic_arm_write(host, SBIC_DATA, msg->msg[0]);

        host->scsi.last_message = msg->msg[0];
#if (DEBUG & DEBUG_MESSAGES)
        spi_print_msg(msg->msg);
#endif
        break;

    default:
        /*
         * ANSI standard says: (SCSI-2 Rev 10c Sect 5.6.14)
         * 'When a target sends this (MESSAGE_REJECT) message, it
         *  shall change to MESSAGE IN phase and send this message
         *  prior to requesting additional message bytes from the
         *  initiator.  This provides an interlock so that the
         *  initiator can determine which message byte is rejected.
         */
        sbic_arm_write(host, SBIC_TRANSCNTH, 0);
        sbic_arm_writenext(host, 0);
        sbic_arm_writenext(host, message_length);
        acornscsi_sbic_issuecmd(host, CMND_XFERINFO);

        msgnr = 0;
        while ((msg = msgqueue_getmsg(&host->scsi.msgs, msgnr++)) != NULL) {
            unsigned int i;
#if (DEBUG & DEBUG_MESSAGES)
            spi_print_msg(msg);
#endif
            i = 0;
            if (acornscsi_write_pio(host, msg->msg, &i, msg->length, 1000000))
                printk("scsi%d: timeout while sending message\n", host->host->host_no);

            host->scsi.last_message = msg->msg[0];
            if (msg->msg[0] == EXTENDED_MESSAGE)
                host->scsi.last_message |= msg->msg[2] << 8;

            if (i != msg->length)
                break;
        }
        break;
    }
#if (DEBUG & DEBUG_MESSAGES)
    printk("\n");
#endif
}

/*
 * Function: void acornscsi_readstatusbyte(AS_Host *host)
 * Purpose : Read status byte from connected target
 * Params  : host - host connected to target
 */
static
void acornscsi_readstatusbyte(AS_Host *host)
{
    acornscsi_sbic_issuecmd(host, CMND_XFERINFO|CMND_SBT);
    acornscsi_sbic_wait(host, ASR_DBR, ASR_DBR, 1000, "reading status byte");
    host->scsi.SCp.Status = sbic_arm_read(host, SBIC_DATA);
}

/*
 * Function: unsigned char acornscsi_readmessagebyte(AS_Host *host)
 * Purpose : Read one message byte from connected target
 * Params  : host - host connected to target
 */
static
unsigned char acornscsi_readmessagebyte(AS_Host *host)
{
    unsigned char message;

    acornscsi_sbic_issuecmd(host, CMND_XFERINFO | CMND_SBT);

    acornscsi_sbic_wait(host, ASR_DBR, ASR_DBR, 1000, "for message byte");

    message = sbic_arm_read(host, SBIC_DATA);

    /* wait for MSGIN-XFER-PAUSED */
    acornscsi_sbic_wait(host, ASR_INT, ASR_INT, 1000, "for interrupt after message byte");

    sbic_arm_read(host, SBIC_SSR);

    return message;
}

/*
 * Function: void acornscsi_message(AS_Host *host)
 * Purpose : Read complete message from connected target & action message
 * Params  : host - host connected to target
 */
static
void acornscsi_message(AS_Host *host)
{
    unsigned char message[16];
    unsigned int msgidx = 0, msglen = 1;

    do {
        message[msgidx] = acornscsi_readmessagebyte(host);

        switch (msgidx) {
        case 0:
            if (message[0] == EXTENDED_MESSAGE ||
                (message[0] >= 0x20 && message[0] <= 0x2f))
                msglen = 2;
            break;

        case 1:
            if (message[0] == EXTENDED_MESSAGE)
                msglen += message[msgidx];
            break;
        }
        msgidx += 1;
        if (msgidx < msglen) {
            acornscsi_sbic_issuecmd(host, CMND_NEGATEACK);

            /* wait for next msg-in */
            acornscsi_sbic_wait(host, ASR_INT, ASR_INT, 1000, "for interrupt after negate ack");
            sbic_arm_read(host, SBIC_SSR);
        }
    } while (msgidx < msglen);

#if (DEBUG & DEBUG_MESSAGES)
    printk("scsi%d.%c: message in: ",
            host->host->host_no, acornscsi_target(host));
    spi_print_msg(message);
    printk("\n");
#endif

    if (host->scsi.phase == PHASE_RECONNECTED) {
        /*
         * ANSI standard says: (Section SCSI-2 Rev. 10c Sect 5.6.17)
         * 'Whenever a target reconnects to an initiator to continue
         *  a tagged I/O process, the SIMPLE QUEUE TAG message shall
         *  be sent immediately following the IDENTIFY message...'
         */
        if (message[0] == SIMPLE_QUEUE_TAG)
            host->scsi.reconnected.tag = message[1];
        if (acornscsi_reconnect_finish(host))
            host->scsi.phase = PHASE_MSGIN;
    }

    switch (message[0]) {
    case ABORT:
    case ABORT_TAG:
    case COMMAND_COMPLETE:
        if (host->scsi.phase != PHASE_STATUSIN) {
            printk(KERN_ERR "scsi%d.%c: command complete following non-status in phase?\n",
                    host->host->host_no, acornscsi_target(host));
            acornscsi_dumplog(host, host->SCpnt->device->id);
        }
        host->scsi.phase = PHASE_DONE;
        host->scsi.SCp.Message = message[0];
        break;

    case SAVE_POINTERS:
        /*
         * ANSI standard says: (Section SCSI-2 Rev. 10c Sect 5.6.20)
         * 'The SAVE DATA POINTER message is sent from a target to
         *  direct the initiator to copy the active data pointer to
         *  the saved data pointer for the current I/O process.
         */
        acornscsi_dma_cleanup(host);
        host->SCpnt->SCp = host->scsi.SCp;
        host->SCpnt->SCp.sent_command = 0;
        host->scsi.phase = PHASE_MSGIN;
        break;

    case RESTORE_POINTERS:
        /*
         * ANSI standard says: (Section SCSI-2 Rev. 10c Sect 5.6.19)
         * 'The RESTORE POINTERS message is sent from a target to
         *  direct the initiator to copy the most recently saved
         *  command, data, and status pointers for the I/O process
         *  to the corresponding active pointers.  The command and
         *  status pointers shall be restored to the beginning of
         *  the present command and status areas.'
         */
        acornscsi_dma_cleanup(host);
        host->scsi.SCp = host->SCpnt->SCp;
        host->scsi.phase = PHASE_MSGIN;
        break;

    case DISCONNECT:
        /*
         * ANSI standard says: (Section SCSI-2 Rev. 10c Sect 6.4.2)
         * 'On those occasions when an error or exception condition occurs
         *  and the target elects to repeat the information transfer, the
         *  target may repeat the transfer either issuing a RESTORE POINTERS
         *  message or by disconnecting without issuing a SAVE POINTERS
         *  message.  When reconnection is completed, the most recent
         *  saved pointer values are restored.'
         */
        acornscsi_dma_cleanup(host);
        host->scsi.phase = PHASE_DISCONNECT;
        break;

    case MESSAGE_REJECT:
#if 0 /* this isn't needed any more */
        /*
         * If we were negociating sync transfer, we don't yet know if
         * this REJECT is for the sync transfer or for the tagged queue/wide
         * transfer.  Re-initiate sync transfer negociation now, and if
         * we got a REJECT in response to SDTR, then it'll be set to DONE.
         */
        if (host->device[host->SCpnt->device->id].sync_state == SYNC_SENT_REQUEST)
            host->device[host->SCpnt->device->id].sync_state = SYNC_NEGOCIATE;
#endif

        /*
         * If we have any messages waiting to go out, then assert ATN now
         */
        if (msgqueue_msglength(&host->scsi.msgs))
            acornscsi_sbic_issuecmd(host, CMND_ASSERTATN);

        switch (host->scsi.last_message) {
#ifdef CONFIG_SCSI_ACORNSCSI_TAGGED_QUEUE
        case HEAD_OF_QUEUE_TAG:
        case ORDERED_QUEUE_TAG:
        case SIMPLE_QUEUE_TAG:
            /*
             * ANSI standard says: (Section SCSI-2 Rev. 10c Sect 5.6.17)
             *  If a target does not implement tagged queuing and a queue tag
             *  message is received, it shall respond with a MESSAGE REJECT
             *  message and accept the I/O process as if it were untagged.
             */
            printk(KERN_NOTICE "scsi%d.%c: disabling tagged queueing\n",
                    host->host->host_no, acornscsi_target(host));
            host->SCpnt->device->simple_tags = 0;
            set_bit(host->SCpnt->device->id * 8 + host->SCpnt->device->lun, host->busyluns);
            break;
#endif
        case EXTENDED_MESSAGE | (EXTENDED_SDTR << 8):
            /*
             * Target can't handle synchronous transfers
             */
            printk(KERN_NOTICE "scsi%d.%c: Using asynchronous transfer\n",
                    host->host->host_no, acornscsi_target(host));
            host->device[host->SCpnt->device->id].sync_xfer = SYNCHTRANSFER_2DBA;
            host->device[host->SCpnt->device->id].sync_state = SYNC_ASYNCHRONOUS;
            sbic_arm_write(host, SBIC_SYNCHTRANSFER, host->device[host->SCpnt->device->id].sync_xfer);
            break;

        default:
            break;
        }
        break;

    case QUEUE_FULL:
        /* TODO: target queue is full */
        break;

    case SIMPLE_QUEUE_TAG:
        /* tag queue reconnect... message[1] = queue tag.  Print something to indicate something happened! */
        printk("scsi%d.%c: reconnect queue tag %02X\n",
                host->host->host_no, acornscsi_target(host),
                message[1]);
        break;

    case EXTENDED_MESSAGE:
        switch (message[2]) {
#ifdef CONFIG_SCSI_ACORNSCSI_SYNC
        case EXTENDED_SDTR:
            if (host->device[host->SCpnt->device->id].sync_state == SYNC_SENT_REQUEST) {
                /*
                 * We requested synchronous transfers.  This isn't quite right...
                 * We can only say if this succeeded if we proceed on to execute the
                 * command from this message.  If we get a MESSAGE PARITY ERROR,
                 * and the target retries fail, then we fallback to asynchronous mode
                 */
                host->device[host->SCpnt->device->id].sync_state = SYNC_COMPLETED;
                printk(KERN_NOTICE "scsi%d.%c: Using synchronous transfer, offset %d, %d ns\n",
                        host->host->host_no, acornscsi_target(host),
                        message[4], message[3] * 4);
                host->device[host->SCpnt->device->id].sync_xfer =
                        calc_sync_xfer(message[3] * 4, message[4]);
            } else {
                unsigned char period, length;
                /*
                 * Target requested synchronous transfers.  The agreement is only
                 * to be in operation AFTER the target leaves message out phase.
                 */
                acornscsi_sbic_issuecmd(host, CMND_ASSERTATN);
                period = max_t(unsigned int, message[3], sdtr_period / 4);
                length = min_t(unsigned int, message[4], sdtr_size);
                msgqueue_addmsg(&host->scsi.msgs, 5, EXTENDED_MESSAGE, 3,
                                 EXTENDED_SDTR, period, length);
                host->device[host->SCpnt->device->id].sync_xfer =
                        calc_sync_xfer(period * 4, length);
            }
            sbic_arm_write(host, SBIC_SYNCHTRANSFER, host->device[host->SCpnt->device->id].sync_xfer);
            break;
#else
            /* We do not accept synchronous transfers.  Respond with a
             * MESSAGE_REJECT.
             */
#endif

        case EXTENDED_WDTR:
            /* The WD33C93A is only 8-bit.  We respond with a MESSAGE_REJECT
             * to a wide data transfer request.
             */
        default:
            acornscsi_sbic_issuecmd(host, CMND_ASSERTATN);
            msgqueue_flush(&host->scsi.msgs);
            msgqueue_addmsg(&host->scsi.msgs, 1, MESSAGE_REJECT);
            break;
        }
        break;

#ifdef CONFIG_SCSI_ACORNSCSI_LINK
    case LINKED_CMD_COMPLETE:
    case LINKED_FLG_CMD_COMPLETE:
        /*
         * We don't support linked commands yet
         */
        if (0) {
#if (DEBUG & DEBUG_LINK)
            printk("scsi%d.%c: lun %d tag %d linked command complete\n",
                    host->host->host_no, acornscsi_target(host), host->SCpnt->tag);
#endif
            /*
             * A linked command should only terminate with one of these messages
             * if there are more linked commands available.
             */
            if (!host->SCpnt->next_link) {
                printk(KERN_WARNING "scsi%d.%c: lun %d tag %d linked command complete, but no next_link\n",
                        instance->host_no, acornscsi_target(host), host->SCpnt->tag);
                acornscsi_sbic_issuecmd(host, CMND_ASSERTATN);
                msgqueue_addmsg(&host->scsi.msgs, 1, ABORT);
            } else {
                struct scsi_cmnd *SCpnt = host->SCpnt;

                acornscsi_dma_cleanup(host);

                host->SCpnt = host->SCpnt->next_link;
                host->SCpnt->tag = SCpnt->tag;
                SCpnt->result = DID_OK | host->scsi.SCp.Message << 8 | host->Scsi.SCp.Status;
                SCpnt->done(SCpnt);

                /* initialise host->SCpnt->SCp */
            }
            break;
        }
#endif

    default: /* reject message */
        printk(KERN_ERR "scsi%d.%c: unrecognised message %02X, rejecting\n",
                host->host->host_no, acornscsi_target(host),
                message[0]);
        acornscsi_sbic_issuecmd(host, CMND_ASSERTATN);
        msgqueue_flush(&host->scsi.msgs);
        msgqueue_addmsg(&host->scsi.msgs, 1, MESSAGE_REJECT);
        host->scsi.phase = PHASE_MSGIN;
        break;
    }
    acornscsi_sbic_issuecmd(host, CMND_NEGATEACK);
}

/*
 * Function: int acornscsi_buildmessages(AS_Host *host)
 * Purpose : build the connection messages for a host
 * Params  : host - host to add messages to
 */
static
void acornscsi_buildmessages(AS_Host *host)
{
#if 0
    /* does the device need resetting? */
    if (cmd_reset) {
        msgqueue_addmsg(&host->scsi.msgs, 1, BUS_DEVICE_RESET);
        return;
    }
#endif

    msgqueue_addmsg(&host->scsi.msgs, 1,
                     IDENTIFY(host->device[host->SCpnt->device->id].disconnect_ok,
                             host->SCpnt->device->lun));

#if 0
    /* does the device need the current command aborted */
    if (cmd_aborted) {
        acornscsi_abortcmd(host->SCpnt->tag);
        return;
    }
#endif

#ifdef CONFIG_SCSI_ACORNSCSI_TAGGED_QUEUE
    if (host->SCpnt->tag) {
        unsigned int tag_type;

        if (host->SCpnt->cmnd[0] == REQUEST_SENSE ||
            host->SCpnt->cmnd[0] == TEST_UNIT_READY ||
            host->SCpnt->cmnd[0] == INQUIRY)
            tag_type = HEAD_OF_QUEUE_TAG;
        else
            tag_type = SIMPLE_QUEUE_TAG;
        msgqueue_addmsg(&host->scsi.msgs, 2, tag_type, host->SCpnt->tag);
    }
#endif

#ifdef CONFIG_SCSI_ACORNSCSI_SYNC
    if (host->device[host->SCpnt->device->id].sync_state == SYNC_NEGOCIATE) {
        host->device[host->SCpnt->device->id].sync_state = SYNC_SENT_REQUEST;
        msgqueue_addmsg(&host->scsi.msgs, 5,
                         EXTENDED_MESSAGE, 3, EXTENDED_SDTR,
                         sdtr_period / 4, sdtr_size);
    }
#endif
}

/*
 * Function: int acornscsi_starttransfer(AS_Host *host)
 * Purpose : transfer data to/from connected target
 * Params  : host - host to which target is connected
 * Returns : 0 if failure
 */
static
int acornscsi_starttransfer(AS_Host *host)
{
    int residual;

    if (!host->scsi.SCp.ptr /*&& host->scsi.SCp.this_residual*/) {
        printk(KERN_ERR "scsi%d.%c: null buffer passed to acornscsi_starttransfer\n",
                host->host->host_no, acornscsi_target(host));
        return 0;
    }

    residual = scsi_bufflen(host->SCpnt) - host->scsi.SCp.scsi_xferred;

    sbic_arm_write(host, SBIC_SYNCHTRANSFER, host->device[host->SCpnt->device->id].sync_xfer);
    sbic_arm_writenext(host, residual >> 16);
    sbic_arm_writenext(host, residual >> 8);
    sbic_arm_writenext(host, residual);
    acornscsi_sbic_issuecmd(host, CMND_XFERINFO);
    return 1;
}

/* =========================================================================================
 * Connection & Disconnection
 */
/*
 * Function : acornscsi_reconnect(AS_Host *host)
 * Purpose  : reconnect a previously disconnected command
 * Params   : host - host specific data
 * Remarks  : SCSI spec says:
 *              'The set of active pointers is restored from the set
 *               of saved pointers upon reconnection of the I/O process'
 */
static
int acornscsi_reconnect(AS_Host *host)
{
    unsigned int target, lun, ok = 0;

    target = sbic_arm_read(host, SBIC_SOURCEID);

    if (!(target & 8))
        printk(KERN_ERR "scsi%d: invalid source id after reselection "
                "- device fault?\n",
                host->host->host_no);

    target &= 7;

    if (host->SCpnt && !host->scsi.disconnectable) {
        printk(KERN_ERR "scsi%d.%d: reconnected while command in "
                "progress to target %d?\n",
                host->host->host_no, target, host->SCpnt->device->id);
        host->SCpnt = NULL;
    }

    lun = sbic_arm_read(host, SBIC_DATA) & 7;

    host->scsi.reconnected.target = target;
    host->scsi.reconnected.lun = lun;
    host->scsi.reconnected.tag = 0;

    if (host->scsi.disconnectable && host->SCpnt &&
        host->SCpnt->device->id == target && host->SCpnt->device->lun == lun)
        ok = 1;

    if (!ok && queue_probetgtlun(&host->queues.disconnected, target, lun))
        ok = 1;

    ADD_STATUS(target, 0x81, host->scsi.phase, 0);

    if (ok) {
        host->scsi.phase = PHASE_RECONNECTED;
    } else {
        /* this doesn't seem to work */
        printk(KERN_ERR "scsi%d.%c: reselected with no command "
                "to reconnect with\n",
                host->host->host_no, '0' + target);
        acornscsi_dumplog(host, target);
        acornscsi_abortcmd(host, 0);
        if (host->SCpnt) {
            queue_add_cmd_tail(&host->queues.disconnected, host->SCpnt);
            host->SCpnt = NULL;
        }
    }
    acornscsi_sbic_issuecmd(host, CMND_NEGATEACK);
    return !ok;
}

/*
 * Function: int acornscsi_reconect_finish(AS_Host *host)
 * Purpose : finish reconnecting a command
 * Params  : host - host to complete
 * Returns : 0 if failed
 */
static
int acornscsi_reconnect_finish(AS_Host *host)
{
    if (host->scsi.disconnectable && host->SCpnt) {
        host->scsi.disconnectable = 0;
        if (host->SCpnt->device->id  == host->scsi.reconnected.target &&
            host->SCpnt->device->lun == host->scsi.reconnected.lun &&
            host->SCpnt->tag         == host->scsi.reconnected.tag) {
#if (DEBUG & (DEBUG_QUEUES|DEBUG_DISCON))
            DBG(host->SCpnt, printk("scsi%d.%c: reconnected",
                    host->host->host_no, acornscsi_target(host)));
#endif
        } else {
            queue_add_cmd_tail(&host->queues.disconnected, host->SCpnt);
#if (DEBUG & (DEBUG_QUEUES|DEBUG_DISCON))
            DBG(host->SCpnt, printk("scsi%d.%c: had to move command "
                    "to disconnected queue\n",
                    host->host->host_no, acornscsi_target(host)));
#endif
            host->SCpnt = NULL;
        }
    }
    if (!host->SCpnt) {
        host->SCpnt = queue_remove_tgtluntag(&host->queues.disconnected,
                                host->scsi.reconnected.target,
                                host->scsi.reconnected.lun,
                                host->scsi.reconnected.tag);
#if (DEBUG & (DEBUG_QUEUES|DEBUG_DISCON))
        DBG(host->SCpnt, printk("scsi%d.%c: had to get command",
                host->host->host_no, acornscsi_target(host)));
#endif
    }

    if (!host->SCpnt)
        acornscsi_abortcmd(host, host->scsi.reconnected.tag);
    else {
        /*
         * Restore data pointer from SAVED pointers.
         */
        host->scsi.SCp = host->SCpnt->SCp;
#if (DEBUG & (DEBUG_QUEUES|DEBUG_DISCON))
        printk(", data pointers: [%p, %X]",
                host->scsi.SCp.ptr, host->scsi.SCp.this_residual);
#endif
    }
#if (DEBUG & (DEBUG_QUEUES|DEBUG_DISCON))
    printk("\n");
#endif

    host->dma.transferred = host->scsi.SCp.scsi_xferred;

    return host->SCpnt != NULL;
}

/*
 * Function: void acornscsi_disconnect_unexpected(AS_Host *host)
 * Purpose : handle an unexpected disconnect
 * Params  : host - host on which disconnect occurred
 */
static
void acornscsi_disconnect_unexpected(AS_Host *host)
{
    printk(KERN_ERR "scsi%d.%c: unexpected disconnect\n",
            host->host->host_no, acornscsi_target(host));
#if (DEBUG & DEBUG_ABORT)
    acornscsi_dumplog(host, 8);
#endif

    acornscsi_done(host, &host->SCpnt, DID_ERROR);
}

/*
 * Function: void acornscsi_abortcmd(AS_host *host, unsigned char tag)
 * Purpose : abort a currently executing command
 * Params  : host - host with connected command to abort
 *           tag  - tag to abort
 */
static
void acornscsi_abortcmd(AS_Host *host, unsigned char tag)
{
    host->scsi.phase = PHASE_ABORTED;
    sbic_arm_write(host, SBIC_CMND, CMND_ASSERTATN);

    msgqueue_flush(&host->scsi.msgs);
#ifdef CONFIG_SCSI_ACORNSCSI_TAGGED_QUEUE
    if (tag)
        msgqueue_addmsg(&host->scsi.msgs, 2, ABORT_TAG, tag);
    else
#endif
        msgqueue_addmsg(&host->scsi.msgs, 1, ABORT);
}

/* ==========================================================================================
 * Interrupt routines.
 */
/*
 * Function: int acornscsi_sbicintr(AS_Host *host)
 * Purpose : handle interrupts from SCSI device
 * Params  : host - host to process
 * Returns : INTR_PROCESS if expecting another SBIC interrupt
 *           INTR_IDLE if no interrupt
 *           INTR_NEXT_COMMAND if we have finished processing the command
 */
static
intr_ret_t acornscsi_sbicintr(AS_Host *host, int in_irq)
{
    unsigned int asr, ssr;

    asr = sbic_arm_read(host, SBIC_ASR);
    if (!(asr & ASR_INT))
        return INTR_IDLE;

    ssr = sbic_arm_read(host, SBIC_SSR);

#if (DEBUG & DEBUG_PHASES)
    print_sbic_status(asr, ssr, host->scsi.phase);
#endif

    ADD_STATUS(8, ssr, host->scsi.phase, in_irq);

    if (host->SCpnt && !host->scsi.disconnectable)
        ADD_STATUS(host->SCpnt->device->id, ssr, host->scsi.phase, in_irq);

    switch (ssr) {
    case 0x00:                          /* reset state - not advanced                   */
        printk(KERN_ERR "scsi%d: reset in standard mode but wanted advanced mode.\n",
                host->host->host_no);
        /* setup sbic - WD33C93A */
        sbic_arm_write(host, SBIC_OWNID, OWNID_EAF | host->host->this_id);
        sbic_arm_write(host, SBIC_CMND, CMND_RESET);

        return INTR_IDLE;

    case 0x01:                          /* reset state - advanced                       */
        sbic_arm_write(host, SBIC_CTRL, INIT_SBICDMA | CTRL_IDI);
        sbic_arm_write(host, SBIC_TIMEOUT, TIMEOUT_TIME);
        sbic_arm_write(host, SBIC_SYNCHTRANSFER, SYNCHTRANSFER_2DBA);
        sbic_arm_write(host, SBIC_SOURCEID, SOURCEID_ER | SOURCEID_DSP);
        msgqueue_flush(&host->scsi.msgs);
        return INTR_IDLE;

    case 0x41:                          /* unexpected disconnect aborted command        */
        acornscsi_disconnect_unexpected(host);
        return INTR_NEXT_COMMAND;
    }

    switch (host->scsi.phase) {
    case PHASE_CONNECTING:              /* STATE: command removed from issue queue      */
        switch (ssr) {
        case 0x11:                      /* -> PHASE_CONNECTED                           */
            /* BUS FREE -> SELECTION */
            host->scsi.phase = PHASE_CONNECTED;
            msgqueue_flush(&host->scsi.msgs);
            host->dma.transferred = host->scsi.SCp.scsi_xferred;
            /* 33C93 gives next interrupt indicating bus phase */
            asr = sbic_arm_read(host, SBIC_ASR);
            if (!(asr & ASR_INT))
                break;
            ssr = sbic_arm_read(host, SBIC_SSR);
            ADD_STATUS(8, ssr, host->scsi.phase, 1);
            ADD_STATUS(host->SCpnt->device->id, ssr, host->scsi.phase, 1);
            goto connected;
            
        case 0x42:                      /* select timed out                             */
                                        /* -> PHASE_IDLE                                */
            acornscsi_done(host, &host->SCpnt, DID_NO_CONNECT);
            return INTR_NEXT_COMMAND;

        case 0x81:                      /* -> PHASE_RECONNECTED or PHASE_ABORTED        */
            /* BUS FREE -> RESELECTION */
            host->origSCpnt = host->SCpnt;
            host->SCpnt = NULL;
            msgqueue_flush(&host->scsi.msgs);
            acornscsi_reconnect(host);
            break;

        default:
            printk(KERN_ERR "scsi%d.%c: PHASE_CONNECTING, SSR %02X?\n",
                    host->host->host_no, acornscsi_target(host), ssr);
            acornscsi_dumplog(host, host->SCpnt ? host->SCpnt->device->id : 8);
            acornscsi_abortcmd(host, host->SCpnt->tag);
        }
        return INTR_PROCESSING;

    connected:
    case PHASE_CONNECTED:               /* STATE: device selected ok                    */
        switch (ssr) {
#ifdef NONSTANDARD
        case 0x8a:                      /* -> PHASE_COMMAND, PHASE_COMMANDPAUSED        */
            /* SELECTION -> COMMAND */
            acornscsi_sendcommand(host);
            break;

        case 0x8b:                      /* -> PHASE_STATUS                              */
            /* SELECTION -> STATUS */
            acornscsi_readstatusbyte(host);
            host->scsi.phase = PHASE_STATUSIN;
            break;
#endif

        case 0x8e:                      /* -> PHASE_MSGOUT                              */
            /* SELECTION ->MESSAGE OUT */
            host->scsi.phase = PHASE_MSGOUT;
            acornscsi_buildmessages(host);
            acornscsi_sendmessage(host);
            break;

        /* these should not happen */
        case 0x85:                      /* target disconnected                          */
            acornscsi_done(host, &host->SCpnt, DID_ERROR);
            break;

        default:
            printk(KERN_ERR "scsi%d.%c: PHASE_CONNECTED, SSR %02X?\n",
                    host->host->host_no, acornscsi_target(host), ssr);
            acornscsi_dumplog(host, host->SCpnt ? host->SCpnt->device->id : 8);
            acornscsi_abortcmd(host, host->SCpnt->tag);
        }
        return INTR_PROCESSING;

    case PHASE_MSGOUT:                  /* STATE: connected & sent IDENTIFY message     */
        /*
         * SCSI standard says that MESSAGE OUT phases can be followed by a
         * DATA phase, STATUS phase, MESSAGE IN phase or COMMAND phase
         */
        switch (ssr) {
        case 0x8a:                      /* -> PHASE_COMMAND, PHASE_COMMANDPAUSED        */
        case 0x1a:                      /* -> PHASE_COMMAND, PHASE_COMMANDPAUSED        */
            /* MESSAGE OUT -> COMMAND */
            acornscsi_sendcommand(host);
            break;

        case 0x8b:                      /* -> PHASE_STATUS                              */
        case 0x1b:                      /* -> PHASE_STATUS                              */
            /* MESSAGE OUT -> STATUS */
            acornscsi_readstatusbyte(host);
            host->scsi.phase = PHASE_STATUSIN;
            break;

        case 0x8e:                      /* -> PHASE_MSGOUT                              */
            /* MESSAGE_OUT(MESSAGE_IN) ->MESSAGE OUT */
            acornscsi_sendmessage(host);
            break;

        case 0x4f:                      /* -> PHASE_MSGIN, PHASE_DISCONNECT             */
        case 0x1f:                      /* -> PHASE_MSGIN, PHASE_DISCONNECT             */
            /* MESSAGE OUT -> MESSAGE IN */
            acornscsi_message(host);
            break;

        default:
            printk(KERN_ERR "scsi%d.%c: PHASE_MSGOUT, SSR %02X?\n",
                    host->host->host_no, acornscsi_target(host), ssr);
            acornscsi_dumplog(host, host->SCpnt ? host->SCpnt->device->id : 8);
        }
        return INTR_PROCESSING;

    case PHASE_COMMAND:                 /* STATE: connected & command sent              */
        switch (ssr) {
        case 0x18:                      /* -> PHASE_DATAOUT                             */
            /* COMMAND -> DATA OUT */
            if (host->scsi.SCp.sent_command != host->SCpnt->cmd_len)
                acornscsi_abortcmd(host, host->SCpnt->tag);
            acornscsi_dma_setup(host, DMA_OUT);
            if (!acornscsi_starttransfer(host))
                acornscsi_abortcmd(host, host->SCpnt->tag);
            host->scsi.phase = PHASE_DATAOUT;
            return INTR_IDLE;

        case 0x19:                      /* -> PHASE_DATAIN                              */
            /* COMMAND -> DATA IN */
            if (host->scsi.SCp.sent_command != host->SCpnt->cmd_len)
                acornscsi_abortcmd(host, host->SCpnt->tag);
            acornscsi_dma_setup(host, DMA_IN);
            if (!acornscsi_starttransfer(host))
                acornscsi_abortcmd(host, host->SCpnt->tag);
            host->scsi.phase = PHASE_DATAIN;
            return INTR_IDLE;

        case 0x1b:                      /* -> PHASE_STATUS                              */
            /* COMMAND -> STATUS */
            acornscsi_readstatusbyte(host);
            host->scsi.phase = PHASE_STATUSIN;
            break;

        case 0x1e:                      /* -> PHASE_MSGOUT                              */
            /* COMMAND -> MESSAGE OUT */
            acornscsi_sendmessage(host);
            break;

        case 0x1f:                      /* -> PHASE_MSGIN, PHASE_DISCONNECT             */
            /* COMMAND -> MESSAGE IN */
            acornscsi_message(host);
            break;

        default:
            printk(KERN_ERR "scsi%d.%c: PHASE_COMMAND, SSR %02X?\n",
                    host->host->host_no, acornscsi_target(host), ssr);
            acornscsi_dumplog(host, host->SCpnt ? host->SCpnt->device->id : 8);
        }
        return INTR_PROCESSING;

    case PHASE_DISCONNECT:              /* STATE: connected, received DISCONNECT msg    */
        if (ssr == 0x85) {              /* -> PHASE_IDLE                                */
            host->scsi.disconnectable = 1;
            host->scsi.reconnected.tag = 0;
            host->scsi.phase = PHASE_IDLE;
            host->stats.disconnects += 1;
        } else {
            printk(KERN_ERR "scsi%d.%c: PHASE_DISCONNECT, SSR %02X instead of disconnect?\n",
                    host->host->host_no, acornscsi_target(host), ssr);
            acornscsi_dumplog(host, host->SCpnt ? host->SCpnt->device->id : 8);
        }
        return INTR_NEXT_COMMAND;

    case PHASE_IDLE:                    /* STATE: disconnected                          */
        if (ssr == 0x81)                /* -> PHASE_RECONNECTED or PHASE_ABORTED        */
            acornscsi_reconnect(host);
        else {
            printk(KERN_ERR "scsi%d.%c: PHASE_IDLE, SSR %02X while idle?\n",
                    host->host->host_no, acornscsi_target(host), ssr);
            acornscsi_dumplog(host, host->SCpnt ? host->SCpnt->device->id : 8);
        }
        return INTR_PROCESSING;

    case PHASE_RECONNECTED:             /* STATE: device reconnected to initiator       */
        /*
         * Command reconnected - if MESGIN, get message - it may be
         * the tag.  If not, get command out of disconnected queue
         */
        /*
         * If we reconnected and we're not in MESSAGE IN phase after IDENTIFY,
         * reconnect I_T_L command
         */
        if (ssr != 0x8f && !acornscsi_reconnect_finish(host))
            return INTR_IDLE;
        ADD_STATUS(host->SCpnt->device->id, ssr, host->scsi.phase, in_irq);
        switch (ssr) {
        case 0x88:                      /* data out phase                               */
                                        /* -> PHASE_DATAOUT                             */
            /* MESSAGE IN -> DATA OUT */
            acornscsi_dma_setup(host, DMA_OUT);
            if (!acornscsi_starttransfer(host))
                acornscsi_abortcmd(host, host->SCpnt->tag);
            host->scsi.phase = PHASE_DATAOUT;
            return INTR_IDLE;

        case 0x89:                      /* data in phase                                */
                                        /* -> PHASE_DATAIN                              */
            /* MESSAGE IN -> DATA IN */
            acornscsi_dma_setup(host, DMA_IN);
            if (!acornscsi_starttransfer(host))
                acornscsi_abortcmd(host, host->SCpnt->tag);
            host->scsi.phase = PHASE_DATAIN;
            return INTR_IDLE;

        case 0x8a:                      /* command out                                  */
            /* MESSAGE IN -> COMMAND */
            acornscsi_sendcommand(host);/* -> PHASE_COMMAND, PHASE_COMMANDPAUSED        */
            break;

        case 0x8b:                      /* status in                                    */
                                        /* -> PHASE_STATUSIN                            */
            /* MESSAGE IN -> STATUS */
            acornscsi_readstatusbyte(host);
            host->scsi.phase = PHASE_STATUSIN;
            break;

        case 0x8e:                      /* message out                                  */
                                        /* -> PHASE_MSGOUT                              */
            /* MESSAGE IN -> MESSAGE OUT */
            acornscsi_sendmessage(host);
            break;

        case 0x8f:                      /* message in                                   */
            acornscsi_message(host);    /* -> PHASE_MSGIN, PHASE_DISCONNECT             */
            break;

        default:
            printk(KERN_ERR "scsi%d.%c: PHASE_RECONNECTED, SSR %02X after reconnect?\n",
                    host->host->host_no, acornscsi_target(host), ssr);
            acornscsi_dumplog(host, host->SCpnt ? host->SCpnt->device->id : 8);
        }
        return INTR_PROCESSING;

    case PHASE_DATAIN:                  /* STATE: transferred data in                   */
        /*
         * This is simple - if we disconnect then the DMA address & count is
         * correct.
         */
        switch (ssr) {
        case 0x19:                      /* -> PHASE_DATAIN                              */
        case 0x89:                      /* -> PHASE_DATAIN                              */
            acornscsi_abortcmd(host, host->SCpnt->tag);
            return INTR_IDLE;

        case 0x1b:                      /* -> PHASE_STATUSIN                            */
        case 0x4b:                      /* -> PHASE_STATUSIN                            */
        case 0x8b:                      /* -> PHASE_STATUSIN                            */
            /* DATA IN -> STATUS */
            host->scsi.SCp.scsi_xferred = scsi_bufflen(host->SCpnt) -
                                          acornscsi_sbic_xfcount(host);
            acornscsi_dma_stop(host);
            acornscsi_readstatusbyte(host);
            host->scsi.phase = PHASE_STATUSIN;
            break;

        case 0x1e:                      /* -> PHASE_MSGOUT                              */
        case 0x4e:                      /* -> PHASE_MSGOUT                              */
        case 0x8e:                      /* -> PHASE_MSGOUT                              */
            /* DATA IN -> MESSAGE OUT */
            host->scsi.SCp.scsi_xferred = scsi_bufflen(host->SCpnt) -
                                          acornscsi_sbic_xfcount(host);
            acornscsi_dma_stop(host);
            acornscsi_sendmessage(host);
            break;

        case 0x1f:                      /* message in                                   */
        case 0x4f:                      /* message in                                   */
        case 0x8f:                      /* message in                                   */
            /* DATA IN -> MESSAGE IN */
            host->scsi.SCp.scsi_xferred = scsi_bufflen(host->SCpnt) -
                                          acornscsi_sbic_xfcount(host);
            acornscsi_dma_stop(host);
            acornscsi_message(host);    /* -> PHASE_MSGIN, PHASE_DISCONNECT             */
            break;

        default:
            printk(KERN_ERR "scsi%d.%c: PHASE_DATAIN, SSR %02X?\n",
                    host->host->host_no, acornscsi_target(host), ssr);
            acornscsi_dumplog(host, host->SCpnt ? host->SCpnt->device->id : 8);
        }
        return INTR_PROCESSING;

    case PHASE_DATAOUT:                 /* STATE: transferred data out                  */
        /*
         * This is more complicated - if we disconnect, the DMA could be 12
         * bytes ahead of us.  We need to correct this.
         */
        switch (ssr) {
        case 0x18:                      /* -> PHASE_DATAOUT                             */
        case 0x88:                      /* -> PHASE_DATAOUT                             */
            acornscsi_abortcmd(host, host->SCpnt->tag);
            return INTR_IDLE;

        case 0x1b:                      /* -> PHASE_STATUSIN                            */
        case 0x4b:                      /* -> PHASE_STATUSIN                            */
        case 0x8b:                      /* -> PHASE_STATUSIN                            */
            /* DATA OUT -> STATUS */
            host->scsi.SCp.scsi_xferred = scsi_bufflen(host->SCpnt) -
                                          acornscsi_sbic_xfcount(host);
            acornscsi_dma_stop(host);
            acornscsi_dma_adjust(host);
            acornscsi_readstatusbyte(host);
            host->scsi.phase = PHASE_STATUSIN;
            break;

        case 0x1e:                      /* -> PHASE_MSGOUT                              */
        case 0x4e:                      /* -> PHASE_MSGOUT                              */
        case 0x8e:                      /* -> PHASE_MSGOUT                              */
            /* DATA OUT -> MESSAGE OUT */
            host->scsi.SCp.scsi_xferred = scsi_bufflen(host->SCpnt) -
                                          acornscsi_sbic_xfcount(host);
            acornscsi_dma_stop(host);
            acornscsi_dma_adjust(host);
            acornscsi_sendmessage(host);
            break;

        case 0x1f:                      /* message in                                   */
        case 0x4f:                      /* message in                                   */
        case 0x8f:                      /* message in                                   */
            /* DATA OUT -> MESSAGE IN */
            host->scsi.SCp.scsi_xferred = scsi_bufflen(host->SCpnt) -
                                          acornscsi_sbic_xfcount(host);
            acornscsi_dma_stop(host);
            acornscsi_dma_adjust(host);
            acornscsi_message(host);    /* -> PHASE_MSGIN, PHASE_DISCONNECT             */
            break;

        default:
            printk(KERN_ERR "scsi%d.%c: PHASE_DATAOUT, SSR %02X?\n",
                    host->host->host_no, acornscsi_target(host), ssr);
            acornscsi_dumplog(host, host->SCpnt ? host->SCpnt->device->id : 8);
        }
        return INTR_PROCESSING;

    case PHASE_STATUSIN:                /* STATE: status in complete                    */
        switch (ssr) {
        case 0x1f:                      /* -> PHASE_MSGIN, PHASE_DONE, PHASE_DISCONNECT */
        case 0x8f:                      /* -> PHASE_MSGIN, PHASE_DONE, PHASE_DISCONNECT */
            /* STATUS -> MESSAGE IN */
            acornscsi_message(host);
            break;

        case 0x1e:                      /* -> PHASE_MSGOUT                              */
        case 0x8e:                      /* -> PHASE_MSGOUT                              */
            /* STATUS -> MESSAGE OUT */
            acornscsi_sendmessage(host);
            break;

        default:
            printk(KERN_ERR "scsi%d.%c: PHASE_STATUSIN, SSR %02X instead of MESSAGE_IN?\n",
                    host->host->host_no, acornscsi_target(host), ssr);
            acornscsi_dumplog(host, host->SCpnt ? host->SCpnt->device->id : 8);
        }
        return INTR_PROCESSING;

    case PHASE_MSGIN:                   /* STATE: message in                            */
        switch (ssr) {
        case 0x1e:                      /* -> PHASE_MSGOUT                              */
        case 0x4e:                      /* -> PHASE_MSGOUT                              */
        case 0x8e:                      /* -> PHASE_MSGOUT                              */
            /* MESSAGE IN -> MESSAGE OUT */
            acornscsi_sendmessage(host);
            break;

        case 0x1f:                      /* -> PHASE_MSGIN, PHASE_DONE, PHASE_DISCONNECT */
        case 0x2f:
        case 0x4f:
        case 0x8f:
            acornscsi_message(host);
            break;

        case 0x85:
            printk("scsi%d.%c: strange message in disconnection\n",
                host->host->host_no, acornscsi_target(host));
            acornscsi_dumplog(host, host->SCpnt ? host->SCpnt->device->id : 8);
            acornscsi_done(host, &host->SCpnt, DID_ERROR);
            break;

        default:
            printk(KERN_ERR "scsi%d.%c: PHASE_MSGIN, SSR %02X after message in?\n",
                    host->host->host_no, acornscsi_target(host), ssr);
            acornscsi_dumplog(host, host->SCpnt ? host->SCpnt->device->id : 8);
        }
        return INTR_PROCESSING;

    case PHASE_DONE:                    /* STATE: received status & message             */
        switch (ssr) {
        case 0x85:                      /* -> PHASE_IDLE                                */
            acornscsi_done(host, &host->SCpnt, DID_OK);
            return INTR_NEXT_COMMAND;

        case 0x1e:
        case 0x8e:
            acornscsi_sendmessage(host);
            break;

        default:
            printk(KERN_ERR "scsi%d.%c: PHASE_DONE, SSR %02X instead of disconnect?\n",
                    host->host->host_no, acornscsi_target(host), ssr);
            acornscsi_dumplog(host, host->SCpnt ? host->SCpnt->device->id : 8);
        }
        return INTR_PROCESSING;

    case PHASE_ABORTED:
        switch (ssr) {
        case 0x85:
            if (host->SCpnt)
                acornscsi_done(host, &host->SCpnt, DID_ABORT);
            else {
                clear_bit(host->scsi.reconnected.target * 8 + host->scsi.reconnected.lun,
                          host->busyluns);
                host->scsi.phase = PHASE_IDLE;
            }
            return INTR_NEXT_COMMAND;

        case 0x1e:
        case 0x2e:
        case 0x4e:
        case 0x8e:
            acornscsi_sendmessage(host);
            break;

        default:
            printk(KERN_ERR "scsi%d.%c: PHASE_ABORTED, SSR %02X?\n",
                    host->host->host_no, acornscsi_target(host), ssr);
            acornscsi_dumplog(host, host->SCpnt ? host->SCpnt->device->id : 8);
        }
        return INTR_PROCESSING;

    default:
        printk(KERN_ERR "scsi%d.%c: unknown driver phase %d\n",
                host->host->host_no, acornscsi_target(host), ssr);
        acornscsi_dumplog(host, host->SCpnt ? host->SCpnt->device->id : 8);
    }
    return INTR_PROCESSING;
}

/*
 * Prototype: void acornscsi_intr(int irq, void *dev_id)
 * Purpose  : handle interrupts from Acorn SCSI card
 * Params   : irq    - interrupt number
 *            dev_id - device specific data (AS_Host structure)
 */
static irqreturn_t
acornscsi_intr(int irq, void *dev_id)
{
    AS_Host *host = (AS_Host *)dev_id;
    intr_ret_t ret;
    int iostatus;
    int in_irq = 0;

    do {
        ret = INTR_IDLE;

        iostatus = readb(host->fast + INT_REG);

        if (iostatus & 2) {
            acornscsi_dma_intr(host);
            iostatus = readb(host->fast + INT_REG);
        }

        if (iostatus & 8)
            ret = acornscsi_sbicintr(host, in_irq);

        /*
         * If we have a transfer pending, start it.
         * Only start it if the interface has already started transferring
         * it's data
         */
        if (host->dma.xfer_required)
            acornscsi_dma_xfer(host);

        if (ret == INTR_NEXT_COMMAND)
            ret = acornscsi_kick(host);

        in_irq = 1;
    } while (ret != INTR_IDLE);

    return IRQ_HANDLED;
}

/*=============================================================================================
 * Interfaces between interrupt handler and rest of scsi code
 */

/*
 * Function : acornscsi_queuecmd(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *))
 * Purpose  : queues a SCSI command
 * Params   : cmd  - SCSI command
 *            done - function called on completion, with pointer to command descriptor
 * Returns  : 0, or < 0 on error.
 */
static int acornscsi_queuecmd_lck(struct scsi_cmnd *SCpnt,
                       void (*done)(struct scsi_cmnd *))
{
    AS_Host *host = (AS_Host *)SCpnt->device->host->hostdata;

    if (!done) {
        /* there should be some way of rejecting errors like this without panicing... */
        panic("scsi%d: queuecommand called with NULL done function [cmd=%p]",
                host->host->host_no, SCpnt);
        return -EINVAL;
    }

#if (DEBUG & DEBUG_NO_WRITE)
    if (acornscsi_cmdtype(SCpnt->cmnd[0]) == CMD_WRITE && (NO_WRITE & (1 << SCpnt->device->id))) {
        printk(KERN_CRIT "scsi%d.%c: WRITE attempted with NO_WRITE flag set\n",
            host->host->host_no, '0' + SCpnt->device->id);
        SCpnt->result = DID_NO_CONNECT << 16;
        done(SCpnt);
        return 0;
    }
#endif

    SCpnt->scsi_done = done;
    SCpnt->host_scribble = NULL;
    SCpnt->result = 0;
    SCpnt->tag = 0;
    SCpnt->SCp.phase = (int)acornscsi_datadirection(SCpnt->cmnd[0]);
    SCpnt->SCp.sent_command = 0;
    SCpnt->SCp.scsi_xferred = 0;

    init_SCp(SCpnt);

    host->stats.queues += 1;

    {
        unsigned long flags;

        if (!queue_add_cmd_ordered(&host->queues.issue, SCpnt)) {
            SCpnt->result = DID_ERROR << 16;
            done(SCpnt);
            return 0;
        }
        local_irq_save(flags);
        if (host->scsi.phase == PHASE_IDLE)
            acornscsi_kick(host);
        local_irq_restore(flags);
    }
    return 0;
}

DEF_SCSI_QCMD(acornscsi_queuecmd)

/*
 * Prototype: void acornscsi_reportstatus(struct scsi_cmnd **SCpntp1, struct scsi_cmnd **SCpntp2, int result)
 * Purpose  : pass a result to *SCpntp1, and check if *SCpntp1 = *SCpntp2
 * Params   : SCpntp1 - pointer to command to return
 *            SCpntp2 - pointer to command to check
 *            result  - result to pass back to mid-level done function
 * Returns  : *SCpntp2 = NULL if *SCpntp1 is the same command structure as *SCpntp2.
 */
static inline void acornscsi_reportstatus(struct scsi_cmnd **SCpntp1,
                                          struct scsi_cmnd **SCpntp2,
                                          int result)
{
        struct scsi_cmnd *SCpnt = *SCpntp1;

    if (SCpnt) {
        *SCpntp1 = NULL;

        SCpnt->result = result;
        SCpnt->scsi_done(SCpnt);
    }

    if (SCpnt == *SCpntp2)
        *SCpntp2 = NULL;
}

enum res_abort { res_not_running, res_success, res_success_clear, res_snooze };

/*
 * Prototype: enum res acornscsi_do_abort(struct scsi_cmnd *SCpnt)
 * Purpose  : abort a command on this host
 * Params   : SCpnt - command to abort
 * Returns  : our abort status
 */
static enum res_abort acornscsi_do_abort(AS_Host *host, struct scsi_cmnd *SCpnt)
{
        enum res_abort res = res_not_running;

        if (queue_remove_cmd(&host->queues.issue, SCpnt)) {
                /*
                 * The command was on the issue queue, and has not been
                 * issued yet.  We can remove the command from the queue,
                 * and acknowledge the abort.  Neither the devices nor the
                 * interface know about the command.
                 */
//#if (DEBUG & DEBUG_ABORT)
                printk("on issue queue ");
//#endif
                res = res_success;
        } else if (queue_remove_cmd(&host->queues.disconnected, SCpnt)) {
                /*
                 * The command was on the disconnected queue.  Simply
                 * acknowledge the abort condition, and when the target
                 * reconnects, we will give it an ABORT message.  The
                 * target should then disconnect, and we will clear
                 * the busylun bit.
                 */
//#if (DEBUG & DEBUG_ABORT)
                printk("on disconnected queue ");
//#endif
                res = res_success;
        } else if (host->SCpnt == SCpnt) {
                unsigned long flags;

//#if (DEBUG & DEBUG_ABORT)
                printk("executing ");
//#endif

                local_irq_save(flags);
                switch (host->scsi.phase) {
                /*
                 * If the interface is idle, and the command is 'disconnectable',
                 * then it is the same as on the disconnected queue.  We simply
                 * remove all traces of the command.  When the target reconnects,
                 * we will give it an ABORT message since the command could not
                 * be found.  When the target finally disconnects, we will clear
                 * the busylun bit.
                 */
                case PHASE_IDLE:
                        if (host->scsi.disconnectable) {
                                host->scsi.disconnectable = 0;
                                host->SCpnt = NULL;
                                res = res_success;
                        }
                        break;

                /*
                 * If the command has connected and done nothing further,
                 * simply force a disconnect.  We also need to clear the
                 * busylun bit.
                 */
                case PHASE_CONNECTED:
                        sbic_arm_write(host, SBIC_CMND, CMND_DISCONNECT);
                        host->SCpnt = NULL;
                        res = res_success_clear;
                        break;

                default:
                        acornscsi_abortcmd(host, host->SCpnt->tag);
                        res = res_snooze;
                }
                local_irq_restore(flags);
        } else if (host->origSCpnt == SCpnt) {
                /*
                 * The command will be executed next, but a command
                 * is currently using the interface.  This is similar to
                 * being on the issue queue, except the busylun bit has
                 * been set.
                 */
                host->origSCpnt = NULL;
//#if (DEBUG & DEBUG_ABORT)
                printk("waiting for execution ");
//#endif
                res = res_success_clear;
        } else
                printk("unknown ");

        return res;
}

/*
 * Prototype: int acornscsi_abort(struct scsi_cmnd *SCpnt)
 * Purpose  : abort a command on this host
 * Params   : SCpnt - command to abort
 * Returns  : one of SCSI_ABORT_ macros
 */
int acornscsi_abort(struct scsi_cmnd *SCpnt)
{
        AS_Host *host = (AS_Host *) SCpnt->device->host->hostdata;
        int result;

        host->stats.aborts += 1;

#if (DEBUG & DEBUG_ABORT)
        {
                int asr, ssr;
                asr = sbic_arm_read(host, SBIC_ASR);
                ssr = sbic_arm_read(host, SBIC_SSR);

                printk(KERN_WARNING "acornscsi_abort: ");
                print_sbic_status(asr, ssr, host->scsi.phase);
                acornscsi_dumplog(host, SCpnt->device->id);
        }
#endif

        printk("scsi%d: ", host->host->host_no);

        switch (acornscsi_do_abort(host, SCpnt)) {
        /*
         * We managed to find the command and cleared it out.
         * We do not expect the command to be executing on the
         * target, but we have set the busylun bit.
         */
        case res_success_clear:
//#if (DEBUG & DEBUG_ABORT)
                printk("clear ");
//#endif
                clear_bit(SCpnt->device->id * 8 + SCpnt->device->lun, host->busyluns);

        /*
         * We found the command, and cleared it out.  Either
         * the command is still known to be executing on the
         * target, or the busylun bit is not set.
         */
        case res_success:
//#if (DEBUG & DEBUG_ABORT)
                printk("success\n");
//#endif
                result = SUCCESS;
                break;

        /*
         * We did find the command, but unfortunately we couldn't
         * unhook it from ourselves.  Wait some more, and if it
         * still doesn't complete, reset the interface.
         */
        case res_snooze:
//#if (DEBUG & DEBUG_ABORT)
                printk("snooze\n");
//#endif
                result = FAILED;
                break;

        /*
         * The command could not be found (either because it completed,
         * or it got dropped.
         */
        default:
        case res_not_running:
                acornscsi_dumplog(host, SCpnt->device->id);
                result = FAILED;
//#if (DEBUG & DEBUG_ABORT)
                printk("not running\n");
//#endif
                break;
        }

        return result;
}

/*
 * Prototype: int acornscsi_reset(struct scsi_cmnd *SCpnt)
 * Purpose  : reset a command on this host/reset this host
 * Params   : SCpnt  - command causing reset
 * Returns  : one of SCSI_RESET_ macros
 */
int acornscsi_bus_reset(struct scsi_cmnd *SCpnt)
{
        AS_Host *host = (AS_Host *)SCpnt->device->host->hostdata;
        struct scsi_cmnd *SCptr;
    
    host->stats.resets += 1;

#if (DEBUG & DEBUG_RESET)
    {
        int asr, ssr;

        asr = sbic_arm_read(host, SBIC_ASR);
        ssr = sbic_arm_read(host, SBIC_SSR);

        printk(KERN_WARNING "acornscsi_reset: ");
        print_sbic_status(asr, ssr, host->scsi.phase);
        acornscsi_dumplog(host, SCpnt->device->id);
    }
#endif

    acornscsi_dma_stop(host);

    /*
     * do hard reset.  This resets all devices on this host, and so we
     * must set the reset status on all commands.
     */
    acornscsi_resetcard(host);

    while ((SCptr = queue_remove(&host->queues.disconnected)) != NULL)
        ;

    return SUCCESS;
}

/*==============================================================================================
 * initialisation & miscellaneous support
 */

/*
 * Function: char *acornscsi_info(struct Scsi_Host *host)
 * Purpose : return a string describing this interface
 * Params  : host - host to give information on
 * Returns : a constant string
 */
const
char *acornscsi_info(struct Scsi_Host *host)
{
    static char string[100], *p;

    p = string;
    
    p += sprintf(string, "%s at port %08lX irq %d v%d.%d.%d"
#ifdef CONFIG_SCSI_ACORNSCSI_SYNC
    " SYNC"
#endif
#ifdef CONFIG_SCSI_ACORNSCSI_TAGGED_QUEUE
    " TAG"
#endif
#ifdef CONFIG_SCSI_ACORNSCSI_LINK
    " LINK"
#endif
#if (DEBUG & DEBUG_NO_WRITE)
    " NOWRITE (" __stringify(NO_WRITE) ")"
#endif
                , host->hostt->name, host->io_port, host->irq,
                VER_MAJOR, VER_MINOR, VER_PATCH);
    return string;
}

int acornscsi_proc_info(struct Scsi_Host *instance, char *buffer, char **start, off_t offset,
                        int length, int inout)
{
    int pos, begin = 0, devidx;
    struct scsi_device *scd;
    AS_Host *host;
    char *p = buffer;

    if (inout == 1)
        return -EINVAL;

    host  = (AS_Host *)instance->hostdata;
    
    p += sprintf(p, "AcornSCSI driver v%d.%d.%d"
#ifdef CONFIG_SCSI_ACORNSCSI_SYNC
    " SYNC"
#endif
#ifdef CONFIG_SCSI_ACORNSCSI_TAGGED_QUEUE
    " TAG"
#endif
#ifdef CONFIG_SCSI_ACORNSCSI_LINK
    " LINK"
#endif
#if (DEBUG & DEBUG_NO_WRITE)
    " NOWRITE (" __stringify(NO_WRITE) ")"
#endif
                "\n\n", VER_MAJOR, VER_MINOR, VER_PATCH);

    p += sprintf(p,     "SBIC: WD33C93A  Address: %p    IRQ : %d\n",
                        host->base + SBIC_REGIDX, host->scsi.irq);
#ifdef USE_DMAC
    p += sprintf(p,     "DMAC: uPC71071  Address: %p  IRQ : %d\n\n",
                        host->base + DMAC_OFFSET, host->scsi.irq);
#endif

    p += sprintf(p,     "Statistics:\n"
                        "Queued commands: %-10u    Issued commands: %-10u\n"
                        "Done commands  : %-10u    Reads          : %-10u\n"
                        "Writes         : %-10u    Others         : %-10u\n"
                        "Disconnects    : %-10u    Aborts         : %-10u\n"
                        "Resets         : %-10u\n\nLast phases:",
                        host->stats.queues,             host->stats.removes,
                        host->stats.fins,               host->stats.reads,
                        host->stats.writes,             host->stats.miscs,
                        host->stats.disconnects,        host->stats.aborts,
                        host->stats.resets);

    for (devidx = 0; devidx < 9; devidx ++) {
        unsigned int statptr, prev;

        p += sprintf(p, "\n%c:", devidx == 8 ? 'H' : ('0' + devidx));
        statptr = host->status_ptr[devidx] - 10;

        if ((signed int)statptr < 0)
            statptr += STATUS_BUFFER_SIZE;

        prev = host->status[devidx][statptr].when;

        for (; statptr != host->status_ptr[devidx]; statptr = (statptr + 1) & (STATUS_BUFFER_SIZE - 1)) {
            if (host->status[devidx][statptr].when) {
                p += sprintf(p, "%c%02X:%02X+%2ld",
                        host->status[devidx][statptr].irq ? '-' : ' ',
                        host->status[devidx][statptr].ph,
                        host->status[devidx][statptr].ssr,
                        (host->status[devidx][statptr].when - prev) < 100 ?
                                (host->status[devidx][statptr].when - prev) : 99);
                prev = host->status[devidx][statptr].when;
            }
        }
    }

    p += sprintf(p, "\nAttached devices:\n");

    shost_for_each_device(scd, instance) {
        p += sprintf(p, "Device/Lun TaggedQ      Sync\n");
        p += sprintf(p, "     %d/%d   ", scd->id, scd->lun);
        if (scd->tagged_supported)
                p += sprintf(p, "%3sabled(%3d) ",
                             scd->simple_tags ? "en" : "dis",
                             scd->current_tag);
        else
                p += sprintf(p, "unsupported  ");

        if (host->device[scd->id].sync_xfer & 15)
                p += sprintf(p, "offset %d, %d ns\n",
                             host->device[scd->id].sync_xfer & 15,
                             acornscsi_getperiod(host->device[scd->id].sync_xfer));
        else
                p += sprintf(p, "async\n");

        pos = p - buffer;
        if (pos + begin < offset) {
            begin += pos;
            p = buffer;
        }
        pos = p - buffer;
        if (pos + begin > offset + length) {
            scsi_device_put(scd);
            break;
        }
    }

    pos = p - buffer;

    *start = buffer + (offset - begin);
    pos -= offset - begin;

    if (pos > length)
        pos = length;

    return pos;
}

static struct scsi_host_template acornscsi_template = {
        .module                 = THIS_MODULE,
        .proc_info              = acornscsi_proc_info,
        .name                   = "AcornSCSI",
        .info                   = acornscsi_info,
        .queuecommand           = acornscsi_queuecmd,
        .eh_abort_handler       = acornscsi_abort,
        .eh_bus_reset_handler   = acornscsi_bus_reset,
        .can_queue              = 16,
        .this_id                = 7,
        .sg_tablesize           = SG_ALL,
        .cmd_per_lun            = 2,
        .use_clustering         = DISABLE_CLUSTERING,
        .proc_name              = "acornscsi",
};

static int __devinit
acornscsi_probe(struct expansion_card *ec, const struct ecard_id *id)
{
        struct Scsi_Host *host;
        AS_Host *ashost;
        int ret;

        ret = ecard_request_resources(ec);
        if (ret)
                goto out;

        host = scsi_host_alloc(&acornscsi_template, sizeof(AS_Host));
        if (!host) {
                ret = -ENOMEM;
                goto out_release;
        }

        ashost = (AS_Host *)host->hostdata;

        ashost->base = ecardm_iomap(ec, ECARD_RES_MEMC, 0, 0);
        ashost->fast = ecardm_iomap(ec, ECARD_RES_IOCFAST, 0, 0);
        if (!ashost->base || !ashost->fast)
                goto out_put;

        host->irq = ec->irq;
        ashost->host = host;
        ashost->scsi.irq = host->irq;

        ec->irqaddr     = ashost->fast + INT_REG;
        ec->irqmask     = 0x0a;

        ret = request_irq(host->irq, acornscsi_intr, IRQF_DISABLED, "acornscsi", ashost);