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acornscsi.c

/*
 *  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

#ifndef STRINGIFY
#define STRINGIFY(x) #x
#endif
#define STRx(x) STRINGIFY(x)
#define NO_WRITE_STR STRx(NO_WRITE)

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sched.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 <asm/system.h>
#include <asm/io.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, 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
 */

static inline void
sbic_arm_write(unsigned int io_port, int reg, int value)
{
    __raw_writeb(reg, io_port);
    __raw_writeb(value, io_port + 4);
}

#define sbic_arm_writenext(io,val) \
      __raw_writeb((val), (io) + 4)

static inline
int sbic_arm_read(unsigned int io_port, int reg)
{
    if(reg == SBIC_ASR)
         return __raw_readl(io_port) & 255;
    __raw_writeb(reg, io_port);
    return __raw_readl(io_port + 4) & 255;
}

#define sbic_arm_readnext(io) \
      __raw_readb((io) + 4)

#ifdef USE_DMAC
#define dmac_read(io_port,reg) \
      inb((io_port) + (reg))

#define dmac_write(io_port,reg,value) \
      ({ outb((value), (io_port) + (reg)); })

#define dmac_clearintr(io_port) \
      ({ outb(0, (io_port)); })

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

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

      mode = dmac_read(host->dma.io_port, DMAC_MODECON);
      addr = dmac_address(host->dma.io_port);
      len  = dmac_read(host->dma.io_port, DMAC_TXCNTHI) << 8 |
             dmac_read(host->dma.io_port, 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->dma.io_port, 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->scsi.io_port, SBIC_TRANSCNTH) << 16;
    length |= sbic_arm_readnext(host->scsi.io_port) << 8;
    length |= sbic_arm_readnext(host->scsi.io_port);

    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->scsi.io_port, 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->scsi.io_port, 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;
    outb(host->card.page_reg, host->card.io_page);

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

    host->card.page_reg = 0;
    outb(host->card.page_reg, host->card.io_page);

    /*
     * Should get a reset from the card
     */
    timeout = 1000;
    do {
      if (inb(host->card.io_intr) & 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->scsi.io_port, SBIC_ASR);
    sbic_arm_read(host->scsi.io_port, SBIC_SSR);

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

    /*
     * Command should cause a reset interrupt
     */
    timeout = 1000;
    do {
      if (inb(host->card.io_intr) & 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->scsi.io_port, SBIC_ASR);
    if (sbic_arm_read(host->scsi.io_port, SBIC_SSR) != 0x01)
      printk(KERN_CRIT "scsi%d: WD33C93A didn't give enhanced reset interrupt\n",
            host->host->host_no);

    sbic_arm_write(host->scsi.io_port, SBIC_CTRL, INIT_SBICDMA | CTRL_IDI);
    sbic_arm_write(host->scsi.io_port, SBIC_TIMEOUT, TIMEOUT_TIME);
    sbic_arm_write(host->scsi.io_port, SBIC_SYNCHTRANSFER, SYNCHTRANSFER_2DBA);
    sbic_arm_write(host->scsi.io_port, SBIC_SOURCEID, SOURCEID_ER | SOURCEID_DSP);

    host->card.page_reg = 0x40;
    outb(host->card.page_reg, host->card.io_page);

    /* setup dmac - uPC71071 */
    dmac_write(host->dma.io_port, DMAC_INIT, 0);
#ifdef USE_DMAC
    dmac_write(host->dma.io_port, DMAC_INIT, INIT_8BIT);
    dmac_write(host->dma.io_port, DMAC_CHANNEL, CHANNEL_0);
    dmac_write(host->dma.io_port, DMAC_DEVCON0, INIT_DEVCON0);
    dmac_write(host->dma.io_port, 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;
    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->scsi.io_port, SBIC_ASR) & (ASR_INT|ASR_BSY|ASR_CIP))) {
      sbic_arm_write(host->scsi.io_port, SBIC_DESTID, SCpnt->device->id);
      sbic_arm_write(host->scsi.io_port, 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, 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, Scsi_Cmnd **SCpntp, unsigned int result)
{
    Scsi_Cmnd *SCpnt = *SCpntp;

    /* clean up */
    sbic_arm_write(host->scsi.io_port, 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(int port, char *buf, int len);
    unsigned int page, offset, len = length;

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

    outb((page & 0x3f) | host->card.page_reg, host->card.io_page);

    while (len > 0) {
      unsigned int this_len;

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

      __acornscsi_in(host->card.io_ram + (offset << 1), ptr, this_len);

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

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

/*
 * 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(int port, char *buf, int len);
    unsigned int page, offset, len = length;

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

    outb((page & 0x3f) | host->card.page_reg, host->card.io_page);

    while (len > 0) {
      unsigned int this_len;

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

      __acornscsi_out(host->card.io_ram + (offset << 1), ptr, this_len);

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

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

/* =========================================================================================
 * 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->dma.io_port, DMAC_MASKREG, MASK_ON);
    dmac_clearintr(host->dma.io_intr_clear);

#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->dma.io_port, 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->dma.io_port, DMAC_TXCNTLO, length);
      dmac_write(host->dma.io_port, DMAC_TXCNTHI, length >> 8);
      dmac_write(host->dma.io_port, DMAC_TXADRLO, address);
      dmac_write(host->dma.io_port, DMAC_TXADRMD, address >> 8);
      dmac_write(host->dma.io_port, DMAC_TXADRHI, 0);
      dmac_write(host->dma.io_port, DMAC_MODECON, mode);
      dmac_write(host->dma.io_port, 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->dma.io_port, DMAC_MASKREG, MASK_ON);
    dmac_clearintr(host->dma.io_intr_clear);

    /*
     * 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->dma.io_port) - 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->dma.io_port, DMAC_MASKREG, MASK_ON);
    dmac_clearintr(host->dma.io_intr_clear);

    /*
     * Calculate amount transferred via DMA
     */
    transferred = dmac_address(host->dma.io_port) - 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->dma.io_port, DMAC_TXCNTLO, length);
      dmac_write(host->dma.io_port, DMAC_TXCNTHI, length >> 8);
      dmac_write(host->dma.io_port, DMAC_TXADRLO, address);
      dmac_write(host->dma.io_port, DMAC_TXADRMD, address >> 8);
      dmac_write(host->dma.io_port, DMAC_TXADRHI, 0);
      dmac_write(host->dma.io_port, 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->dma.io_port, DMAC_STATUS) & STATUS_RQ0) {
          acornscsi_abortcmd(host, host->SCpnt->tag);

          dmac_write(host->dma.io_port, DMAC_TXCNTLO, 0);
          dmac_write(host->dma.io_port, DMAC_TXCNTHI, 0);
          dmac_write(host->dma.io_port, DMAC_TXADRLO, 0);
          dmac_write(host->dma.io_port, DMAC_TXADRMD, 0);
          dmac_write(host->dma.io_port, DMAC_TXADRHI, 0);
          dmac_write(host->dma.io_port, 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->dma.io_port, DMAC_TXADRLO, transferred);
          dmac_write(host->dma.io_port, DMAC_TXADRMD, transferred >> 8);
          dmac_write(host->dma.io_port, 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->scsi.io_port, SBIC_ASR);

            if (asr & ASR_DBR) {
                  timeout = max_timeout;

                  sbic_arm_write(host->scsi.io_port, 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)
{
    Scsi_Cmnd *SCpnt = host->SCpnt;

    sbic_arm_write(host->scsi.io_port, SBIC_TRANSCNTH, 0);
    sbic_arm_writenext(host->scsi.io_port, 0);
    sbic_arm_writenext(host->scsi.io_port, 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->scsi.io_port, 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->scsi.io_port, 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->scsi.io_port, SBIC_TRANSCNTH, 0);
      sbic_arm_writenext(host->scsi.io_port, 0);
      sbic_arm_writenext(host->scsi.io_port, 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->scsi.io_port, 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->scsi.io_port, 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->scsi.io_port, 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->scsi.io_port, 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->scsi.io_port, 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->scsi.io_port, 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 {
            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 = host->SCpnt->request_bufflen - host->scsi.SCp.scsi_xferred;

    sbic_arm_write(host->scsi.io_port, SBIC_SYNCHTRANSFER, host->device[host->SCpnt->device->id].sync_xfer);
    sbic_arm_writenext(host->scsi.io_port, residual >> 16);
    sbic_arm_writenext(host->scsi.io_port, residual >> 8);
    sbic_arm_writenext(host->scsi.io_port, 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->scsi.io_port, 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->scsi.io_port, 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->scsi.io_port, 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->scsi.io_port, SBIC_ASR);
    if (!(asr & ASR_INT))
      return INTR_IDLE;

    ssr = sbic_arm_read(host->scsi.io_port, 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->scsi.io_port, SBIC_OWNID, OWNID_EAF | host->host->this_id);
      sbic_arm_write(host->scsi.io_port, SBIC_CMND, CMND_RESET);
      return INTR_IDLE;

    case 0x01:                      /* reset state - advanced                 */
      sbic_arm_write(host->scsi.io_port, SBIC_CTRL, INIT_SBICDMA | CTRL_IDI);
      sbic_arm_write(host->scsi.io_port, SBIC_TIMEOUT, TIMEOUT_TIME);
      sbic_arm_write(host->scsi.io_port, SBIC_SYNCHTRANSFER, SYNCHTRANSFER_2DBA);
      sbic_arm_write(host->scsi.io_port, 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->scsi.io_port, SBIC_ASR);
          if (!(asr & ASR_INT))
            break;
          ssr = sbic_arm_read(host->scsi.io_port, 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 = host->SCpnt->request_bufflen -
                                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 = host->SCpnt->request_bufflen -
                                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 = host->SCpnt->request_bufflen -
                                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 = host->SCpnt->request_bufflen -
                                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 = host->SCpnt->request_bufflen -
                                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 = host->SCpnt->request_bufflen -
                                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, struct pt_regs *regs)
 * Purpose  : handle interrupts from Acorn SCSI card
 * Params   : irq    - interrupt number
 *          dev_id - device specific data (AS_Host structure)
 *          regs   - processor registers when interrupt occurred
 */
static irqreturn_t
acornscsi_intr(int irq, void *dev_id, struct pt_regs *regs)
{
    AS_Host *host = (AS_Host *)dev_id;
    intr_ret_t ret;
    int iostatus;
    int in_irq = 0;

    do {
      ret = INTR_IDLE;

      iostatus = inb(host->card.io_intr);

      if (iostatus & 2) {
          acornscsi_dma_intr(host);
          iostatus = inb(host->card.io_intr);
      }

      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(Scsi_Cmnd *cmd, void (*done)(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.
 */
int acornscsi_queuecmd(Scsi_Cmnd *SCpnt, void (*done)(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;
}

/*
 * Prototype: void acornscsi_reportstatus(Scsi_Cmnd **SCpntp1, 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(Scsi_Cmnd **SCpntp1, Scsi_Cmnd **SCpntp2, int result)
{
    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(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, 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->scsi.io_port, 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(Scsi_Cmnd *SCpnt)
 * Purpose  : abort a command on this host
 * Params   : SCpnt - command to abort
 * Returns  : one of SCSI_ABORT_ macros
 */
int acornscsi_abort(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->scsi.io_port, SBIC_ASR);
            ssr = sbic_arm_read(host->scsi.io_port, 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
            SCpnt->result = DID_ABORT << 16;
            SCpnt->scsi_done(SCpnt);
            result = SCSI_ABORT_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 = SCSI_ABORT_SNOOZE;
            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);
#if (DEBUG & DEBUG_ABORT)
            result = SCSI_ABORT_SNOOZE;
#else
            result = SCSI_ABORT_NOT_RUNNING;
#endif
//#if (DEBUG & DEBUG_ABORT)
            printk("not running\n");
//#endif
            break;
      }

      return result;
}

/*
 * Prototype: int acornscsi_reset(Scsi_Cmnd *SCpnt, unsigned int reset_flags)
 * Purpose  : reset a command on this host/reset this host
 * Params   : SCpnt  - command causing reset
 *          result - what type of reset to perform
 * Returns  : one of SCSI_RESET_ macros
 */
int acornscsi_reset(Scsi_Cmnd *SCpnt, unsigned int reset_flags)
{
    AS_Host *host = (AS_Host *)SCpnt->device->host->hostdata;
    Scsi_Cmnd *SCptr;
    
    host->stats.resets += 1;

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

      asr = sbic_arm_read(host->scsi.io_port, SBIC_ASR);
      ssr = sbic_arm_read(host->scsi.io_port, 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);

    SCptr = host->SCpnt;

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

    /*
     * report reset on commands current connected/disconnected
     */
    acornscsi_reportstatus(&host->SCpnt, &SCptr, DID_RESET);

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

    if (SCpnt) {
      SCpnt->result = DID_RESET << 16;
      SCpnt->scsi_done(SCpnt);
    }

    return SCSI_RESET_BUS_RESET | SCSI_RESET_HOST_RESET | SCSI_RESET_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 ("NO_WRITE_STR")"
#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 ("NO_WRITE_STR")"
#endif
            "\n\n", VER_MAJOR, VER_MINOR, VER_PATCH);

    p += sprintf(p,     "SBIC: WD33C93A  Address: %08X  IRQ : %d\n",
                  host->scsi.io_port, host->scsi.irq);
#ifdef USE_DMAC
    p += sprintf(p,     "DMAC: uPC71071  Address: %08X  IRQ : %d\n\n",
                  host->dma.io_port, 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,
#warning fixme
      .abort                  = acornscsi_abort,
      .reset                  = acornscsi_reset,
      .can_queue        = 16,
      .this_id          = 7,
      .sg_tablesize           = SG_ALL,
      .cmd_per_lun            = 2,
      .unchecked_isa_dma      = 0,
      .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 = -ENOMEM;

      host = scsi_host_alloc(&acornscsi_template, sizeof(AS_Host));
      if (!host)
            goto out;

      ashost = (AS_Host *)host->hostdata;

      host->io_port = ecard_address(ec, ECARD_MEMC, 0);
      host->irq = ec->irq;

      ashost->host            = host;
      ashost->scsi.io_port    = ioaddr(host->io_port + 0x800);
      ashost->scsi.irq  = host->irq;
      ashost->card.io_intr    = POD_SPACE(host->io_port) + 0x800;
      ashost->card.io_page    = POD_SPACE(host->io_port) + 0xc00;
      ashost->card.io_ram     = ioaddr(host->io_port);
      ashost->dma.io_port     = host->io_port + 0xc00;
      ashost->dma.io_intr_clear = POD_SPACE(host->io_port) + 0x800;

      ec->irqaddr = (char *)ioaddr(ashost->card.io_intr);
      ec->irqmask = 0x0a;

      ret = -EBUSY;
      if (!request_region(host->io_port + 0x800, 2, "acornscsi(sbic)"))
            goto err_1;
      if (!request_region(ashost->card.io_intr, 1, "acornscsi(intr)"))
            goto err_2;
      if (!request_region(ashost->card.io_page, 1, "acornscsi(page)"))
            goto err_3;
#ifdef USE_DMAC
      if (!request_region(ashost->dma.io_port, 256, "acornscsi(dmac)"))
            goto err_4;
#endif
      if (!request_region(host->io_port, 2048, "acornscsi(ram)"))
            goto err_5;

      ret = request_irq(host->irq, acornscsi_intr, IRQF_DISABLED, "acornscsi", ashost);
      if (ret) {
            printk(KERN_CRIT "scsi%d: IRQ%d not free: %d\n",
                  host->host_no, ashost->scsi.irq, ret);
            goto err_6;
      }

      memset(&ashost->stats, 0, sizeof (ashost->stats));
      queue_initialise(&ashost->queues.issue);
      queue_initialise(&ashost->queues.disconnected);
      msgqueue_initialise(&ashost->scsi.msgs);

      acornscsi_resetcard(ashost);

      ret = scsi_add_host(host, &ec->dev);
      if (ret)
            goto err_7;

      scsi_scan_host(host);
      goto out;

 err_7:
      free_irq(host->irq, ashost);
 err_6:
      release_region(host->io_port, 2048);
 err_5:
#ifdef USE_DMAC
      release_region(ashost->dma.io_port, 256);
#endif
 err_4:
      release_region(ashost->card.io_page, 1);
 err_3:
      release_region(ashost->card.io_intr, 1);    
 err_2:
      release_region(host->io_port + 0x800, 2);
 err_1:
      scsi_host_put(host);
 out:
      return ret;
}

static void __devexit acornscsi_remove(struct expansion_card *ec)
{
      struct Scsi_Host *host = ecard_get_drvdata(ec);
      AS_Host *ashost = (AS_Host *)host->hostdata;

      ecard_set_drvdata(ec, NULL);
      scsi_remove_host(host);

      /*
       * Put card into RESET state
       */
      outb(0x80, ashost->card.io_page);

      free_irq(host->irq, ashost);

      release_region(host->io_port + 0x800, 2);
      release_region(ashost->card.io_intr, 1);
      release_region(ashost->card.io_page, 1);
      release_region(ashost->dma.io_port, 256);
      release_region(host->io_port, 2048);

      msgqueue_free(&ashost->scsi.msgs);
      queue_free(&ashost->queues.disconnected);
      queue_free(&ashost->queues.issue);
      scsi_host_put(host);
}

static const struct ecard_id acornscsi_cids[] = {
      { MANU_ACORN, PROD_ACORN_SCSI },
      { 0xffff, 0xffff },
};

static struct ecard_driver acornscsi_driver = {
      .probe            = acornscsi_probe,
      .remove           = __devexit_p(acornscsi_remove),
      .id_table   = acornscsi_cids,
      .drv = {
            .name       = "acornscsi",
      },
};

static int __init acornscsi_init(void)
{
      return ecard_register_driver(&acornscsi_driver);
}

static void __exit acornscsi_exit(void)
{
      ecard_remove_driver(&acornscsi_driver);
}

module_init(acornscsi_init);
module_exit(acornscsi_exit);

MODULE_AUTHOR("Russell King");
MODULE_DESCRIPTION("AcornSCSI driver");
MODULE_LICENSE("GPL");

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