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seagate.c

/*
 *    seagate.c Copyright (C) 1992, 1993 Drew Eckhardt
 *      low level scsi driver for ST01/ST02, Future Domain TMC-885,
 *      TMC-950 by Drew Eckhardt <drew@colorado.edu>
 *
 *      Note : TMC-880 boards don't work because they have two bits in
 *              the status register flipped, I'll fix this "RSN"
 *    [why do I have strong feeling that above message is from 1993? :-)
 *            pavel@ucw.cz]
 *
 *      This card does all the I/O via memory mapped I/O, so there is no need
 *      to check or allocate a region of the I/O address space.
 */

/* 1996 - to use new read{b,w,l}, write{b,w,l}, and phys_to_virt
 * macros, replaced assembler routines with C. There's probably a
 * performance hit, but I only have a cdrom and can't tell. Define
 * SEAGATE_USE_ASM if you want the old assembler code -- SJT
 *
 * 1998-jul-29 - created DPRINTK macros and made it work under 
 * linux 2.1.112, simplified some #defines etc. <pavel@ucw.cz>
 *
 * Aug 2000 - aeb - deleted seagate_st0x_biosparam(). It would try to
 * read the physical disk geometry, a bad mistake. Of course it doesn't
 * matter much what geometry one invents, but on large disks it
 * returned 256 (or more) heads, causing all kind of failures.
 * Of course this means that people might see a different geometry now,
 * so boot parameters may be necessary in some cases.
 */

/*
 * Configuration :
 * To use without BIOS -DOVERRIDE=base_address -DCONTROLLER=FD or SEAGATE
 * -DIRQ will override the default of 5.
 * Note: You can now set these options from the kernel's "command line".
 * The syntax is:
 *
 *     st0x=ADDRESS,IRQ                (for a Seagate controller)
 * or:
 *     tmc8xx=ADDRESS,IRQ              (for a TMC-8xx or TMC-950 controller)
 * eg:
 *     tmc8xx=0xC8000,15
 *
 * will configure the driver for a TMC-8xx style controller using IRQ 15
 * with a base address of 0xC8000.
 *
 * -DARBITRATE 
 *      Will cause the host adapter to arbitrate for the
 *      bus for better SCSI-II compatibility, rather than just
 *      waiting for BUS FREE and then doing its thing.  Should
 *      let us do one command per Lun when I integrate my
 *      reorganization changes into the distribution sources.
 *
 * -DDEBUG=65535
 *      Will activate debug code.
 *
 * -DFAST or -DFAST32 
 *      Will use blind transfers where possible
 *
 * -DPARITY  
 *      This will enable parity.
 *
 * -DSEAGATE_USE_ASM
 *      Will use older seagate assembly code. should be (very small amount)
 *      Faster.
 *
 * -DSLOW_RATE=50
 *      Will allow compatibility with broken devices that don't
 *      handshake fast enough (ie, some CD ROM's) for the Seagate
 *      code.
 *
 *      50 is some number, It will let you specify a default
 *      transfer rate if handshaking isn't working correctly.
 *
 * -DOLDCNTDATASCEME  There is a new sceme to set the CONTROL
 *                    and DATA reigsters which complies more closely
 *                    with the SCSI2 standard. This hopefully eliminates
 *                    the need to swap the order these registers are
 *                    'messed' with. It makes the following two options
 *                    obsolete. To reenable the old sceme define this.
 *
 * The following to options are patches from the SCSI.HOWTO
 *
 * -DSWAPSTAT  This will swap the definitions for STAT_MSG and STAT_CD.
 *
 * -DSWAPCNTDATA  This will swap the order that seagate.c messes with
 *                the CONTROL an DATA registers.
 */

#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/signal.h>
#include <linux/string.h>
#include <linux/proc_fs.h>
#include <linux/init.h>
#include <linux/blkdev.h>
#include <linux/stat.h>
#include <linux/delay.h>
#include <linux/io.h>

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

#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi.h>

#include <scsi/scsi_dbg.h>
#include <scsi/scsi_host.h>


#ifdef DEBUG
#define DPRINTK( when, msg... ) do { if ( (DEBUG & (when)) == (when) ) printk( msg ); } while (0)
#else
#define DPRINTK( when, msg... ) do { } while (0)
#define DEBUG 0
#endif
#define DANY( msg... ) DPRINTK( 0xffff, msg );

#ifndef IRQ
#define IRQ 5
#endif

#ifdef FAST32
#define FAST
#endif

#undef LINKED                 /* Linked commands are currently broken! */

#if defined(OVERRIDE) && !defined(CONTROLLER)
#error Please use -DCONTROLLER=SEAGATE or -DCONTROLLER=FD to override controller type
#endif

#ifndef __i386__
#undef SEAGATE_USE_ASM
#endif

/*
      Thanks to Brian Antoine for the example code in his Messy-Loss ST-01
            driver, and Mitsugu Suzuki for information on the ST-01
            SCSI host.
*/

/*
      CONTROL defines
*/

#define CMD_RST         0x01
#define CMD_SEL         0x02
#define CMD_BSY         0x04
#define CMD_ATTN              0x08
#define CMD_START_ARB         0x10
#define CMD_EN_PARITY         0x20
#define CMD_INTR        0x40
#define CMD_DRVR_ENABLE       0x80

/*
      STATUS
*/
#ifdef SWAPSTAT
#define STAT_MSG        0x08
#define STAT_CD               0x02
#else
#define STAT_MSG        0x02
#define STAT_CD               0x08
#endif

#define STAT_BSY        0x01
#define STAT_IO               0x04
#define STAT_REQ        0x10
#define STAT_SEL        0x20
#define STAT_PARITY           0x40
#define STAT_ARB_CMPL         0x80

/* 
      REQUESTS
*/

#define REQ_MASK (STAT_CD |  STAT_IO | STAT_MSG)
#define REQ_DATAOUT 0
#define REQ_DATAIN STAT_IO
#define REQ_CMDOUT STAT_CD
#define REQ_STATIN (STAT_CD | STAT_IO)
#define REQ_MSGOUT (STAT_MSG | STAT_CD)
#define REQ_MSGIN (STAT_MSG | STAT_CD | STAT_IO)

extern volatile int seagate_st0x_timeout;

#ifdef PARITY
#define BASE_CMD CMD_EN_PARITY
#else
#define BASE_CMD  0
#endif

/*
      Debugging code
*/

#define PHASE_BUS_FREE 1
#define PHASE_ARBITRATION 2
#define PHASE_SELECTION 4
#define PHASE_DATAIN 8
#define PHASE_DATAOUT 0x10
#define PHASE_CMDOUT 0x20
#define PHASE_MSGIN 0x40
#define PHASE_MSGOUT 0x80
#define PHASE_STATUSIN 0x100
#define PHASE_ETC (PHASE_DATAIN | PHASE_DATAOUT | PHASE_CMDOUT | PHASE_MSGIN | PHASE_MSGOUT | PHASE_STATUSIN)
#define PRINT_COMMAND 0x200
#define PHASE_EXIT 0x400
#define PHASE_RESELECT 0x800
#define DEBUG_FAST 0x1000
#define DEBUG_SG   0x2000
#define DEBUG_LINKED    0x4000
#define DEBUG_BORKEN    0x8000

/* 
 *    Control options - these are timeouts specified in .01 seconds.
 */

/* 30, 20 work */
#define ST0X_BUS_FREE_DELAY 25
#define ST0X_SELECTION_DELAY 25

#define SEAGATE 1       /* these determine the type of the controller */
#define FD  2

#define ST0X_ID_STR     "Seagate ST-01/ST-02"
#define FD_ID_STR "TMC-8XX/TMC-950"

static int internal_command (unsigned char target, unsigned char lun,
                       const void *cmnd,
                       void *buff, int bufflen, int reselect);

static int incommand;         /* set if arbitration has finished
                           and we are in some command phase. */

static unsigned int base_address = 0;     /* Where the card ROM starts, used to 
                                 calculate memory mapped register
                                 location.  */

static void __iomem *st0x_cr_sr;    /* control register write, status
                                 register read.  256 bytes in
                                 length.
                                 Read is status of SCSI BUS, as per 
                                 STAT masks.  */

static void __iomem *st0x_dr; /* data register, read write 256
                           bytes in length.  */

static volatile int st0x_aborted = 0;     /* set when we are aborted, ie by a
                                 time out, etc.  */

static unsigned char controller_type = 0; /* set to SEAGATE for ST0x
                                       boards or FD for TMC-8xx
                                       boards */
static int irq = IRQ;

module_param(base_address, uint, 0);
module_param(controller_type, byte, 0);
module_param(irq, int, 0);
MODULE_LICENSE("GPL");


#define retcode(result) (((result) << 16) | (message << 8) | status)
#define STATUS ((u8) readb(st0x_cr_sr))
#define DATA ((u8) readb(st0x_dr))
#define WRITE_CONTROL(d) { writeb((d), st0x_cr_sr); }
#define WRITE_DATA(d) { writeb((d), st0x_dr); }

#ifndef OVERRIDE
static unsigned int seagate_bases[] = {
      0xc8000, 0xca000, 0xcc000,
      0xce000, 0xdc000, 0xde000
};

typedef struct {
      const unsigned char *signature;
      unsigned offset;
      unsigned length;
      unsigned char type;
} Signature;

static Signature __initdata signatures[] = {
      {"ST01 v1.7  (C) Copyright 1987 Seagate", 15, 37, SEAGATE},
      {"SCSI BIOS 2.00  (C) Copyright 1987 Seagate", 15, 40, SEAGATE},

/*
 * The following two lines are NOT mistakes.  One detects ROM revision
 * 3.0.0, the other 3.2.  Since seagate has only one type of SCSI adapter,
 * and this is not going to change, the "SEAGATE" and "SCSI" together
 * are probably "good enough"
 */

      {"SEAGATE SCSI BIOS ", 16, 17, SEAGATE},
      {"SEAGATE SCSI BIOS ", 17, 17, SEAGATE},

/*
 * However, future domain makes several incompatible SCSI boards, so specific
 * signatures must be used.
 */

      {"FUTURE DOMAIN CORP. (C) 1986-1989 V5.0C2/14/89", 5, 46, FD},
      {"FUTURE DOMAIN CORP. (C) 1986-1989 V6.0A7/28/89", 5, 46, FD},
      {"FUTURE DOMAIN CORP. (C) 1986-1990 V6.0105/31/90", 5, 47, FD},
      {"FUTURE DOMAIN CORP. (C) 1986-1990 V6.0209/18/90", 5, 47, FD},
      {"FUTURE DOMAIN CORP. (C) 1986-1990 V7.009/18/90", 5, 46, FD},
      {"FUTURE DOMAIN CORP. (C) 1992 V8.00.004/02/92", 5, 44, FD},
      {"IBM F1 BIOS V1.1004/30/92", 5, 25, FD},
      {"FUTURE DOMAIN TMC-950", 5, 21, FD},
      /* Added for 2.2.16 by Matthias_Heidbrink@b.maus.de */
      {"IBM F1 V1.2009/22/93", 5, 25, FD},
};

#define NUM_SIGNATURES ARRAY_SIZE(signatures)
#endif                        /* n OVERRIDE */

/*
 * hostno stores the hostnumber, as told to us by the init routine.
 */

static int hostno = -1;
static void seagate_reconnect_intr (int, void *);
static irqreturn_t do_seagate_reconnect_intr (int, void *);
static int seagate_st0x_bus_reset(struct scsi_cmnd *);

#ifdef FAST
static int fast = 1;
#else
#define fast 0
#endif

#ifdef SLOW_RATE
/*
 * Support for broken devices :
 * The Seagate board has a handshaking problem.  Namely, a lack
 * thereof for slow devices.  You can blast 600K/second through
 * it if you are polling for each byte, more if you do a blind
 * transfer.  In the first case, with a fast device, REQ will
 * transition high-low or high-low-high before your loop restarts
 * and you'll have no problems.  In the second case, the board
 * will insert wait states for up to 13.2 usecs for REQ to
 * transition low->high, and everything will work.
 *
 * However, there's nothing in the state machine that says
 * you *HAVE* to see a high-low-high set of transitions before
 * sending the next byte, and slow things like the Trantor CD ROMS
 * will break because of this.
 *
 * So, we need to slow things down, which isn't as simple as it
 * seems.  We can't slow things down period, because then people
 * who don't recompile their kernels will shoot me for ruining
 * their performance.  We need to do it on a case per case basis.
 *
 * The best for performance will be to, only for borken devices
 * (this is stored on a per-target basis in the scsi_devices array)
 *
 * Wait for a low->high transition before continuing with that
 * transfer.  If we timeout, continue anyways.  We don't need
 * a long timeout, because REQ should only be asserted until the
 * corresponding ACK is received and processed.
 *
 * Note that we can't use the system timer for this, because of
 * resolution, and we *really* can't use the timer chip since
 * gettimeofday() and the beeper routines use that.  So,
 * the best thing for us to do will be to calibrate a timing
 * loop in the initialization code using the timer chip before
 * gettimeofday() can screw with it.
 *
 * FIXME: this is broken (not borken :-). Empty loop costs less than
 * loop with ISA access in it! -- pavel@ucw.cz
 */

static int borken_calibration = 0;

static void __init borken_init (void)
{
      register int count = 0, start = jiffies + 1, stop = start + 25;

      /* FIXME: There may be a better approach, this is a straight port for
         now */
      preempt_disable();
      while (time_before (jiffies, start))
            cpu_relax();
      for (; time_before (jiffies, stop); ++count)
            cpu_relax();
      preempt_enable();

/*
 * Ok, we now have a count for .25 seconds.  Convert to a
 * count per second and divide by transfer rate in K.  */

      borken_calibration = (count * 4) / (SLOW_RATE * 1024);

      if (borken_calibration < 1)
            borken_calibration = 1;
}

static inline void borken_wait (void)
{
      register int count;

      for (count = borken_calibration; count && (STATUS & STAT_REQ); --count)
            cpu_relax();
            
#if (DEBUG & DEBUG_BORKEN)
      if (count)
            printk ("scsi%d : borken timeout\n", hostno);
#endif
}

#endif                        /* def SLOW_RATE */

/* These beasts only live on ISA, and ISA means 8MHz. Each ULOOP()
 * contains at least one ISA access, which takes more than 0.125
 * usec. So if we loop 8 times time in usec, we are safe.
 */

#define ULOOP( i ) for (clock = i*8;;)
#define TIMEOUT (!(clock--))

static int __init seagate_st0x_detect (struct scsi_host_template * tpnt)
{
      struct Scsi_Host *instance;
      int i, j;
      unsigned long cr, dr;

      tpnt->proc_name = "seagate";
/*
 *    First, we try for the manual override.
 */
      DANY ("Autodetecting ST0x / TMC-8xx\n");

      if (hostno != -1) {
            printk (KERN_ERR "seagate_st0x_detect() called twice?!\n");
            return 0;
      }

/* If the user specified the controller type from the command line,
   controller_type will be non-zero, so don't try to detect one */

      if (!controller_type) {
#ifdef OVERRIDE
            base_address = OVERRIDE;
            controller_type = CONTROLLER;

            DANY ("Base address overridden to %x, controller type is %s\n",
                  base_address,
                  controller_type == SEAGATE ? "SEAGATE" : "FD");
#else                   /* OVERRIDE */
/*
 *    To detect this card, we simply look for the signature
 *      from the BIOS version notice in all the possible locations
 *      of the ROM's.  This has a nice side effect of not trashing
 *      any register locations that might be used by something else.
 *
 * XXX - note that we probably should be probing the address
 * space for the on-board RAM instead.
 */

            for (i = 0; i < ARRAY_SIZE(seagate_bases); ++i) {
                  void __iomem *p = ioremap(seagate_bases[i], 0x2000);
                  if (!p)
                        continue;
                  for (j = 0; j < NUM_SIGNATURES; ++j)
                        if (check_signature(p + signatures[j].offset, signatures[j].signature, signatures[j].length)) {
                              base_address = seagate_bases[i];
                              controller_type = signatures[j].type;
                              break;
                        }
                  iounmap(p);
            }
#endif                        /* OVERRIDE */
      }
      /* (! controller_type) */
      tpnt->this_id = (controller_type == SEAGATE) ? 7 : 6;
      tpnt->name = (controller_type == SEAGATE) ? ST0X_ID_STR : FD_ID_STR;

      if (!base_address) {
            printk(KERN_INFO "seagate: ST0x/TMC-8xx not detected.\n");
            return 0;
      }

      cr = base_address + (controller_type == SEAGATE ? 0x1a00 : 0x1c00);
      dr = cr + 0x200;
      st0x_cr_sr = ioremap(cr, 0x100);
      st0x_dr = ioremap(dr, 0x100);

      DANY("%s detected. Base address = %x, cr = %x, dr = %x\n",
            tpnt->name, base_address, cr, dr);

      /*
       *    At all times, we will use IRQ 5.  Should also check for IRQ3
       *    if we lose our first interrupt.
       */
      instance = scsi_register (tpnt, 0);
      if (instance == NULL)
            return 0;

      hostno = instance->host_no;
      if (request_irq (irq, do_seagate_reconnect_intr, IRQF_DISABLED, (controller_type == SEAGATE) ? "seagate" : "tmc-8xx", instance)) {
            printk(KERN_ERR "scsi%d : unable to allocate IRQ%d\n", hostno, irq);
            return 0;
      }
      instance->irq = irq;
      instance->io_port = base_address;
#ifdef SLOW_RATE
      printk(KERN_INFO "Calibrating borken timer... ");
      borken_init();
      printk(" %d cycles per transfer\n", borken_calibration);
#endif
      printk (KERN_INFO "This is one second... ");
      {
            int clock;
            ULOOP (1 * 1000 * 1000) {
                  STATUS;
                  if (TIMEOUT)
                        break;
            }
      }

      printk ("done, %s options:"
#ifdef ARBITRATE
            " ARBITRATE"
#endif
#if DEBUG
            " DEBUG"
#endif
#ifdef FAST
            " FAST"
#ifdef FAST32
            "32"
#endif
#endif
#ifdef LINKED
            " LINKED"
#endif
#ifdef PARITY
            " PARITY"
#endif
#ifdef SEAGATE_USE_ASM
            " SEAGATE_USE_ASM"
#endif
#ifdef SLOW_RATE
            " SLOW_RATE"
#endif
#ifdef SWAPSTAT
            " SWAPSTAT"
#endif
#ifdef SWAPCNTDATA
            " SWAPCNTDATA"
#endif
            "\n", tpnt->name);
      return 1;
}

static const char *seagate_st0x_info (struct Scsi_Host *shpnt)
{
      static char buffer[64];

      snprintf(buffer, 64, "%s at irq %d, address 0x%05X",
             (controller_type == SEAGATE) ? ST0X_ID_STR : FD_ID_STR,
             irq, base_address);
      return buffer;
}

/*
 * These are our saved pointers for the outstanding command that is
 * waiting for a reconnect
 */

static unsigned char current_target, current_lun;
static unsigned char *current_cmnd, *current_data;
static int current_nobuffs;
static struct scatterlist *current_buffer;
static int current_bufflen;

#ifdef LINKED
/*
 * linked_connected indicates whether or not we are currently connected to
 * linked_target, linked_lun and in an INFORMATION TRANSFER phase,
 * using linked commands.
 */

static int linked_connected = 0;
static unsigned char linked_target, linked_lun;
#endif

static void (*done_fn) (struct scsi_cmnd *) = NULL;
static struct scsi_cmnd *SCint = NULL;

/*
 * These control whether or not disconnect / reconnect will be attempted,
 * or are being attempted.
 */

#define NO_RECONNECT    0
#define RECONNECT_NOW   1
#define CAN_RECONNECT   2

/*
 * LINKED_RIGHT indicates that we are currently connected to the correct target
 * for this command, LINKED_WRONG indicates that we are connected to the wrong
 * target. Note that these imply CAN_RECONNECT and require defined(LINKED).
 */

#define LINKED_RIGHT    3
#define LINKED_WRONG    4

/*
 * This determines if we are expecting to reconnect or not.
 */

static int should_reconnect = 0;

/*
 * The seagate_reconnect_intr routine is called when a target reselects the
 * host adapter.  This occurs on the interrupt triggered by the target
 * asserting SEL.
 */

static irqreturn_t do_seagate_reconnect_intr(int irq, void *dev_id)
{
      unsigned long flags;
      struct Scsi_Host *dev = dev_id;
      
      spin_lock_irqsave (dev->host_lock, flags);
      seagate_reconnect_intr (irq, dev_id);
      spin_unlock_irqrestore (dev->host_lock, flags);
      return IRQ_HANDLED;
}

static void seagate_reconnect_intr (int irq, void *dev_id)
{
      int temp;
      struct scsi_cmnd *SCtmp;

      DPRINTK (PHASE_RESELECT, "scsi%d : seagate_reconnect_intr() called\n", hostno);

      if (!should_reconnect)
            printk(KERN_WARNING "scsi%d: unexpected interrupt.\n", hostno);
      else {
            should_reconnect = 0;

            DPRINTK (PHASE_RESELECT, "scsi%d : internal_command(%d, %08x, %08x, RECONNECT_NOW\n", 
                  hostno, current_target, current_data, current_bufflen);

            temp = internal_command (current_target, current_lun, current_cmnd, current_data, current_bufflen, RECONNECT_NOW);

            if (msg_byte(temp) != DISCONNECT) {
                  if (done_fn) {
                        DPRINTK(PHASE_RESELECT, "scsi%d : done_fn(%d,%08x)", hostno, hostno, temp);
                        if (!SCint)
                              panic ("SCint == NULL in seagate");
                        SCtmp = SCint;
                        SCint = NULL;
                        SCtmp->result = temp;
                        done_fn(SCtmp);
                  } else
                        printk(KERN_ERR "done_fn() not defined.\n");
            }
      }
}

/*
 * The seagate_st0x_queue_command() function provides a queued interface
 * to the seagate SCSI driver.  Basically, it just passes control onto the
 * seagate_command() function, after fixing it so that the done_fn()
 * is set to the one passed to the function.  We have to be very careful,
 * because there are some commands on some devices that do not disconnect,
 * and if we simply call the done_fn when the command is done then another
 * command is started and queue_command is called again...  We end up
 * overflowing the kernel stack, and this tends not to be such a good idea.
 */

static int recursion_depth = 0;

static int seagate_st0x_queue_command(struct scsi_cmnd * SCpnt,
                              void (*done) (struct scsi_cmnd *))
{
      int result, reconnect;
      struct scsi_cmnd *SCtmp;

      DANY ("seagate: que_command");
      done_fn = done;
      current_target = SCpnt->device->id;
      current_lun = SCpnt->device->lun;
      current_cmnd = SCpnt->cmnd;
      current_data = (unsigned char *) SCpnt->request_buffer;
      current_bufflen = SCpnt->request_bufflen;
      SCint = SCpnt;
      if (recursion_depth)
            return 1;
      recursion_depth++;
      do {
#ifdef LINKED
            /*
             * Set linked command bit in control field of SCSI command.
             */

            current_cmnd[SCpnt->cmd_len] |= 0x01;
            if (linked_connected) {
                  DPRINTK (DEBUG_LINKED, "scsi%d : using linked commands, current I_T_L nexus is ", hostno);
                  if (linked_target == current_target && linked_lun == current_lun) 
                  {
                        DPRINTK(DEBUG_LINKED, "correct\n");
                        reconnect = LINKED_RIGHT;
                  } else {
                        DPRINTK(DEBUG_LINKED, "incorrect\n");
                        reconnect = LINKED_WRONG;
                  }
            } else
#endif                        /* LINKED */
                  reconnect = CAN_RECONNECT;

            result = internal_command(SCint->device->id, SCint->device->lun, SCint->cmnd,
                              SCint->request_buffer, SCint->request_bufflen, reconnect);
            if (msg_byte(result) == DISCONNECT)
                  break;
            SCtmp = SCint;
            SCint = NULL;
            SCtmp->result = result;
            done_fn(SCtmp);
      }
      while (SCint);
      recursion_depth--;
      return 0;
}

static int internal_command (unsigned char target, unsigned char lun,
              const void *cmnd, void *buff, int bufflen, int reselect)
{
      unsigned char *data = NULL;
      struct scatterlist *buffer = NULL;
      int clock, temp, nobuffs = 0, done = 0, len = 0;
#if DEBUG
      int transfered = 0, phase = 0, newphase;
#endif
      register unsigned char status_read;
      unsigned char tmp_data, tmp_control, status = 0, message = 0;
      unsigned transfersize = 0, underflow = 0;
#ifdef SLOW_RATE
      int borken = (int) SCint->device->borken; /* Does the current target require
                                             Very Slow I/O ?  */
#endif

      incommand = 0;
      st0x_aborted = 0;

#if (DEBUG & PRINT_COMMAND)
      printk("scsi%d : target = %d, command = ", hostno, target);
      __scsi_print_command((unsigned char *) cmnd);
#endif

#if (DEBUG & PHASE_RESELECT)
      switch (reselect) {
      case RECONNECT_NOW:
            printk("scsi%d : reconnecting\n", hostno);
            break;
#ifdef LINKED
      case LINKED_RIGHT:
            printk("scsi%d : connected, can reconnect\n", hostno);
            break;
      case LINKED_WRONG:
            printk("scsi%d : connected to wrong target, can reconnect\n",
                  hostno);
            break;
#endif
      case CAN_RECONNECT:
            printk("scsi%d : allowed to reconnect\n", hostno);
            break;
      default:
            printk("scsi%d : not allowed to reconnect\n", hostno);
      }
#endif

      if (target == (controller_type == SEAGATE ? 7 : 6))
            return DID_BAD_TARGET;

      /*
       *    We work it differently depending on if this is is "the first time,"
       *      or a reconnect.  If this is a reselect phase, then SEL will
       *      be asserted, and we must skip selection / arbitration phases.
       */

      switch (reselect) {
      case RECONNECT_NOW:
            DPRINTK (PHASE_RESELECT, "scsi%d : phase RESELECT \n", hostno);
            /*
             *    At this point, we should find the logical or of our ID
             *    and the original target's ID on the BUS, with BSY, SEL,
             *    and I/O signals asserted.
             *
             *      After ARBITRATION phase is completed, only SEL, BSY,
             *    and the target ID are asserted.  A valid initiator ID
             *    is not on the bus until IO is asserted, so we must wait
             *    for that.
             */
            ULOOP (100 * 1000) {
                  temp = STATUS;
                  if ((temp & STAT_IO) && !(temp & STAT_BSY))
                        break;
                  if (TIMEOUT) {
                        DPRINTK (PHASE_RESELECT, "scsi%d : RESELECT timed out while waiting for IO .\n", hostno);
                        return (DID_BAD_INTR << 16);
                  }
            }

            /*
             *    After I/O is asserted by the target, we can read our ID
             *    and its ID off of the BUS.
             */

            if (!((temp = DATA) & (controller_type == SEAGATE ? 0x80 : 0x40))) {
                  DPRINTK (PHASE_RESELECT, "scsi%d : detected reconnect request to different target.\n\tData bus = %d\n", hostno, temp);
                  return (DID_BAD_INTR << 16);
            }

            if (!(temp & (1 << current_target))) {
                  printk(KERN_WARNING "scsi%d : Unexpected reselect interrupt.  Data bus = %d\n", hostno, temp);
                  return (DID_BAD_INTR << 16);
            }

            buffer = current_buffer;
            cmnd = current_cmnd;    /* WDE add */
            data = current_data;    /* WDE add */
            len = current_bufflen;  /* WDE add */
            nobuffs = current_nobuffs;

            /*
             *    We have determined that we have been selected.  At this
             *    point, we must respond to the reselection by asserting
             *    BSY ourselves
             */

#if 1
            WRITE_CONTROL (BASE_CMD | CMD_DRVR_ENABLE | CMD_BSY);
#else
            WRITE_CONTROL (BASE_CMD | CMD_BSY);
#endif

            /*
             *    The target will drop SEL, and raise BSY, at which time
             *    we must drop BSY.
             */

            ULOOP (100 * 1000) {
                  if (!(STATUS & STAT_SEL))
                        break;
                  if (TIMEOUT) {
                        WRITE_CONTROL (BASE_CMD | CMD_INTR);
                        DPRINTK (PHASE_RESELECT, "scsi%d : RESELECT timed out while waiting for SEL.\n", hostno);
                        return (DID_BAD_INTR << 16);
                  }
            }
            WRITE_CONTROL (BASE_CMD);
            /*
             *    At this point, we have connected with the target
             *    and can get on with our lives.
             */
            break;
      case CAN_RECONNECT:
#ifdef LINKED
            /*
             * This is a bletcherous hack, just as bad as the Unix #!
             * interpreter stuff. If it turns out we are using the wrong
             * I_T_L nexus, the easiest way to deal with it is to go into
             *  our INFORMATION TRANSFER PHASE code, send a ABORT
             * message on MESSAGE OUT phase, and then loop back to here.
             */
connect_loop:
#endif
            DPRINTK (PHASE_BUS_FREE, "scsi%d : phase = BUS FREE \n", hostno);

            /*
             *    BUS FREE PHASE
             *
             *      On entry, we make sure that the BUS is in a BUS FREE
             *      phase, by insuring that both BSY and SEL are low for
             *      at least one bus settle delay.  Several reads help
             *      eliminate wire glitch.
             */

#ifndef ARBITRATE
#error FIXME: this is broken: we may not use jiffies here - we are under cli(). It will hardlock.
            clock = jiffies + ST0X_BUS_FREE_DELAY;

            while (((STATUS | STATUS | STATUS) & (STAT_BSY | STAT_SEL)) && (!st0x_aborted) && time_before (jiffies, clock))
                  cpu_relax();

            if (time_after (jiffies, clock))
                  return retcode (DID_BUS_BUSY);
            else if (st0x_aborted)
                  return retcode (st0x_aborted);
#endif
            DPRINTK (PHASE_SELECTION, "scsi%d : phase = SELECTION\n", hostno);

            clock = jiffies + ST0X_SELECTION_DELAY;

            /*
             * Arbitration/selection procedure :
             * 1.  Disable drivers
             * 2.  Write HOST adapter address bit
             * 3.  Set start arbitration.
             * 4.  We get either ARBITRATION COMPLETE or SELECT at this
             *     point.
             * 5.  OR our ID and targets on bus.
             * 6.  Enable SCSI drivers and asserted SEL and ATTN
             */

#ifdef ARBITRATE
            /* FIXME: verify host lock is always held here */
            WRITE_CONTROL(0);
            WRITE_DATA((controller_type == SEAGATE) ? 0x80 : 0x40);
            WRITE_CONTROL(CMD_START_ARB);

            ULOOP (ST0X_SELECTION_DELAY * 10000) {
                  status_read = STATUS;
                  if (status_read & STAT_ARB_CMPL)
                        break;
                  if (st0x_aborted) /* FIXME: What? We are going to do something even after abort? */
                        break;
                  if (TIMEOUT || (status_read & STAT_SEL)) {
                        printk(KERN_WARNING "scsi%d : arbitration lost or timeout.\n", hostno);
                        WRITE_CONTROL (BASE_CMD);
                        return retcode (DID_NO_CONNECT);
                  }
            }
            DPRINTK (PHASE_SELECTION, "scsi%d : arbitration complete\n", hostno);
#endif

            /*
             *    When the SCSI device decides that we're gawking at it, 
             *    it will respond by asserting BUSY on the bus.
             *
             *    Note : the Seagate ST-01/02 product manual says that we
             *    should twiddle the DATA register before the control
             *    register. However, this does not work reliably so we do
             *    it the other way around.
             *
             *    Probably could be a problem with arbitration too, we
             *    really should try this with a SCSI protocol or logic 
             *    analyzer to see what is going on.
             */
            tmp_data = (unsigned char) ((1 << target) | (controller_type == SEAGATE ? 0x80 : 0x40));
            tmp_control = BASE_CMD | CMD_DRVR_ENABLE | CMD_SEL | (reselect ? CMD_ATTN : 0);

            /* FIXME: verify host lock is always held here */
#ifdef OLDCNTDATASCEME
#ifdef SWAPCNTDATA
            WRITE_CONTROL (tmp_control);
            WRITE_DATA (tmp_data);
#else
            WRITE_DATA (tmp_data);
            WRITE_CONTROL (tmp_control);
#endif
#else
            tmp_control ^= CMD_BSY; /* This is guesswork. What used to be in driver    */
            WRITE_CONTROL (tmp_control);  /* could never work: it sent data into control     */
            WRITE_DATA (tmp_data);  /* register and control info into data. Hopefully  */
            tmp_control ^= CMD_BSY; /* fixed, but order of first two may be wrong.     */
            WRITE_CONTROL (tmp_control);  /* -- pavel@ucw.cz   */
#endif

            ULOOP (250 * 1000) {
                  if (st0x_aborted) {
                        /*
                         *    If we have been aborted, and we have a
                         *    command in progress, IE the target 
                         *    still has BSY asserted, then we will
                         *    reset the bus, and notify the midlevel
                         *    driver to expect sense.
                         */

                        WRITE_CONTROL (BASE_CMD);
                        if (STATUS & STAT_BSY) {
                              printk(KERN_WARNING "scsi%d : BST asserted after we've been aborted.\n", hostno);
                              seagate_st0x_bus_reset(NULL);
                              return retcode (DID_RESET);
                        }
                        return retcode (st0x_aborted);
                  }
                  if (STATUS & STAT_BSY)
                        break;
                  if (TIMEOUT) {
                        DPRINTK (PHASE_SELECTION, "scsi%d : NO CONNECT with target %d, stat = %x \n", hostno, target, STATUS);
                        return retcode (DID_NO_CONNECT);
                  }
            }

            /* Establish current pointers.  Take into account scatter / gather */

            if ((nobuffs = SCint->use_sg)) {
#if (DEBUG & DEBUG_SG)
                  {
                        int i;
                        printk("scsi%d : scatter gather requested, using %d buffers.\n", hostno, nobuffs);
                        for (i = 0; i < nobuffs; ++i)
                              printk("scsi%d : buffer %d address = %p length = %d\n",
                                   hostno, i,
                                   sg_virt(&buffer[i]),
                                   buffer[i].length);
                  }
#endif

                  buffer = (struct scatterlist *) SCint->request_buffer;
                  len = buffer->length;
                  data = sg_virt(buffer);
            } else {
                  DPRINTK (DEBUG_SG, "scsi%d : scatter gather not requested.\n", hostno);
                  buffer = NULL;
                  len = SCint->request_bufflen;
                  data = (unsigned char *) SCint->request_buffer;
            }

            DPRINTK (PHASE_DATAIN | PHASE_DATAOUT, "scsi%d : len = %d\n",
                   hostno, len);

            break;
#ifdef LINKED
      case LINKED_RIGHT:
            break;
      case LINKED_WRONG:
            break;
#endif
      }                 /* end of switch(reselect) */

      /*
       *    There are several conditions under which we wish to send a message :
       *      1.  When we are allowing disconnect / reconnect, and need to
       *    establish the I_T_L nexus via an IDENTIFY with the DiscPriv bit
       *    set.
       *
       *      2.  When we are doing linked commands, are have the wrong I_T_L
       *    nexus established and want to send an ABORT message.
       */

      /* GCC does not like an ifdef inside a macro, so do it the hard way. */
#ifdef LINKED
      WRITE_CONTROL (BASE_CMD | CMD_DRVR_ENABLE | (((reselect == CAN_RECONNECT)|| (reselect == LINKED_WRONG))? CMD_ATTN : 0));
#else
      WRITE_CONTROL (BASE_CMD | CMD_DRVR_ENABLE | (((reselect == CAN_RECONNECT))? CMD_ATTN : 0));
#endif

      /*
       *    INFORMATION TRANSFER PHASE
       *
       *      The nasty looking read / write inline assembler loops we use for
       *      DATAIN and DATAOUT phases are approximately 4-5 times as fast as
       *      the 'C' versions - since we're moving 1024 bytes of data, this
       *      really adds up.
       *
       *      SJT: The nasty-looking assembler is gone, so it's slower.
       *
       */

      DPRINTK (PHASE_ETC, "scsi%d : phase = INFORMATION TRANSFER\n", hostno);

      incommand = 1;
      transfersize = SCint->transfersize;
      underflow = SCint->underflow;

      /*
       *    Now, we poll the device for status information,
       *      and handle any requests it makes.  Note that since we are unsure
       *    of how much data will be flowing across the system, etc and
       *    cannot make reasonable timeouts, that we will instead have the
       *    midlevel driver handle any timeouts that occur in this phase.
       */

      while (((status_read = STATUS) & STAT_BSY) && !st0x_aborted && !done) {
#ifdef PARITY
            if (status_read & STAT_PARITY) {
                  printk(KERN_ERR "scsi%d : got parity error\n", hostno);
                  st0x_aborted = DID_PARITY;
            }
#endif
            if (status_read & STAT_REQ) {
#if ((DEBUG & PHASE_ETC) == PHASE_ETC)
                  if ((newphase = (status_read & REQ_MASK)) != phase) {
                        phase = newphase;
                        switch (phase) {
                        case REQ_DATAOUT:
                              printk ("scsi%d : phase = DATA OUT\n", hostno);
                              break;
                        case REQ_DATAIN:
                              printk ("scsi%d : phase = DATA IN\n", hostno);
                              break;
                        case REQ_CMDOUT:
                              printk
                                  ("scsi%d : phase = COMMAND OUT\n", hostno);
                              break;
                        case REQ_STATIN:
                              printk ("scsi%d : phase = STATUS IN\n",   hostno);
                              break;
                        case REQ_MSGOUT:
                              printk
                                  ("scsi%d : phase = MESSAGE OUT\n", hostno);
                              break;
                        case REQ_MSGIN:
                              printk ("scsi%d : phase = MESSAGE IN\n", hostno);
                              break;
                        default:
                              printk ("scsi%d : phase = UNKNOWN\n", hostno);
                              st0x_aborted = DID_ERROR;
                        }
                  }
#endif
                  switch (status_read & REQ_MASK) {
                  case REQ_DATAOUT:
                        /*
                         * If we are in fast mode, then we simply splat
                         * the data out in word-sized chunks as fast as
                         * we can.
                         */

                        if (!len) {
#if 0
                              printk("scsi%d: underflow to target %d lun %d \n", hostno, target, lun);
                              st0x_aborted = DID_ERROR;
                              fast = 0;
#endif
                              break;
                        }

                        if (fast && transfersize
                            && !(len % transfersize)
                            && (len >= transfersize)
#ifdef FAST32
                            && !(transfersize % 4)
#endif
                            ) {
                              DPRINTK (DEBUG_FAST,
                                     "scsi%d : FAST transfer, underflow = %d, transfersize = %d\n"
                                     "         len = %d, data = %08x\n",
                                     hostno, SCint->underflow,
                                     SCint->transfersize, len,
                                     data);

                  /* SJT: Start. Fast Write */
#ifdef SEAGATE_USE_ASM
                              __asm__ ("cld\n\t"
#ifdef FAST32
                                     "shr $2, %%ecx\n\t"
                                     "1:\t"
                                     "lodsl\n\t"
                                     "movl %%eax, (%%edi)\n\t"
#else
                                     "1:\t"
                                     "lodsb\n\t"
                                     "movb %%al, (%%edi)\n\t"
#endif
                                     "loop 1b;"
                              /* output */ :
                              /* input */ :"D" (st0x_dr),
                                     "S"
                                     (data),
                                     "c" (SCint->transfersize)
/* clobbered */
                              :      "eax", "ecx",
                                     "esi");
#else                   /* SEAGATE_USE_ASM */
                              memcpy_toio(st0x_dr, data, transfersize);
#endif                        /* SEAGATE_USE_ASM */
/* SJT: End */
                              len -= transfersize;
                              data += transfersize;
                              DPRINTK (DEBUG_FAST, "scsi%d : FAST transfer complete len = %d data = %08x\n", hostno, len, data);
                        } else {
                              /*
                               *    We loop as long as we are in a 
                               *    data out phase, there is data to
                               *    send, and BSY is still active.
                               */

/* SJT: Start. Slow Write. */
#ifdef SEAGATE_USE_ASM

                              int __dummy_1, __dummy_2;

/*
 *      We loop as long as we are in a data out phase, there is data to send, 
 *      and BSY is still active.
 */
/* Local variables : len = ecx , data = esi, 
                     st0x_cr_sr = ebx, st0x_dr =  edi
*/
                              __asm__ (
                                          /* Test for any data here at all. */
                                          "orl %%ecx, %%ecx\n\t"
                                          "jz 2f\n\t" "cld\n\t"
/*                    "movl st0x_cr_sr, %%ebx\n\t"  */
/*                    "movl st0x_dr, %%edi\n\t"  */
                                          "1:\t"
                                          "movb (%%ebx), %%al\n\t"
                                          /* Test for BSY */
                                          "test $1, %%al\n\t"
                                          "jz 2f\n\t"
                                          /* Test for data out phase - STATUS & REQ_MASK should be 
                                             REQ_DATAOUT, which is 0. */
                                          "test $0xe, %%al\n\t"
                                          "jnz 2f\n\t"
                                          /* Test for REQ */
                                          "test $0x10, %%al\n\t"
                                          "jz 1b\n\t"
                                          "lodsb\n\t"
                                          "movb %%al, (%%edi)\n\t"
                                          "loop 1b\n\t" "2:\n"
                              /* output */ :"=S" (data), "=c" (len),
                                          "=b"
                                          (__dummy_1),
                                          "=D" (__dummy_2)
/* input */
                              :           "0" (data), "1" (len),
                                          "2" (st0x_cr_sr),
                                          "3" (st0x_dr)
/* clobbered */
                              :           "eax");
#else                   /* SEAGATE_USE_ASM */
                              while (len) {
                                    unsigned char stat;

                                    stat = STATUS;
                                    if (!(stat & STAT_BSY)
                                        || ((stat & REQ_MASK) !=
                                          REQ_DATAOUT))
                                          break;
                                    if (stat & STAT_REQ) {
                                          WRITE_DATA (*data++);
                                          --len;
                                    }
                              }
#endif                        /* SEAGATE_USE_ASM */
/* SJT: End. */
                        }

                        if (!len && nobuffs) {
                              --nobuffs;
                              ++buffer;
                              len = buffer->length;
                              data = sg_virt(buffer);
                              DPRINTK (DEBUG_SG,
                                     "scsi%d : next scatter-gather buffer len = %d address = %08x\n",
                                     hostno, len, data);
                        }
                        break;

                  case REQ_DATAIN:
#ifdef SLOW_RATE
                        if (borken) {
#if (DEBUG & (PHASE_DATAIN))
                              transfered += len;
#endif
                              for (; len && (STATUS & (REQ_MASK | STAT_REQ)) == (REQ_DATAIN | STAT_REQ); --len) {
                                    *data++ = DATA;
                                    borken_wait();
                              }
#if (DEBUG & (PHASE_DATAIN))
                              transfered -= len;
#endif
                        } else
#endif

                              if (fast && transfersize
                                  && !(len % transfersize)
                                  && (len >= transfersize)
#ifdef FAST32
                                  && !(transfersize % 4)
#endif
                            ) {
                              DPRINTK (DEBUG_FAST,
                                     "scsi%d : FAST transfer, underflow = %d, transfersize = %d\n"
                                     "         len = %d, data = %08x\n",
                                     hostno, SCint->underflow,
                                     SCint->transfersize, len,
                                     data);

/* SJT: Start. Fast Read */
#ifdef SEAGATE_USE_ASM
                              __asm__ ("cld\n\t"
#ifdef FAST32
                                     "shr $2, %%ecx\n\t"
                                     "1:\t"
                                     "movl (%%esi), %%eax\n\t"
                                     "stosl\n\t"
#else
                                     "1:\t"
                                     "movb (%%esi), %%al\n\t"
                                     "stosb\n\t"
#endif
                                     "loop 1b\n\t"
                              /* output */ :
                              /* input */ :"S" (st0x_dr),
                                     "D"
                                     (data),
                                     "c" (SCint->transfersize)
/* clobbered */
                              :      "eax", "ecx",
                                     "edi");
#else                   /* SEAGATE_USE_ASM */
                              memcpy_fromio(data, st0x_dr, len);
#endif                        /* SEAGATE_USE_ASM */
/* SJT: End */
                              len -= transfersize;
                              data += transfersize;
#if (DEBUG & PHASE_DATAIN)
                              printk ("scsi%d: transfered += %d\n", hostno, transfersize);
                              transfered += transfersize;
#endif

                              DPRINTK (DEBUG_FAST, "scsi%d : FAST transfer complete len = %d data = %08x\n", hostno, len, data);
                        } else {

#if (DEBUG & PHASE_DATAIN)
                              printk ("scsi%d: transfered += %d\n", hostno, len);
                              transfered += len;      /* Assume we'll transfer it all, then
                                                   subtract what we *didn't* transfer */
#endif

/*
 *    We loop as long as we are in a data in phase, there is room to read,
 *      and BSY is still active
 */

/* SJT: Start. */
#ifdef SEAGATE_USE_ASM

                              int __dummy_3, __dummy_4;

/* Dummy clobbering variables for the new gcc-2.95 */

/*
 *      We loop as long as we are in a data in phase, there is room to read, 
 *      and BSY is still active
 */
                              /* Local variables : ecx = len, edi = data
                                 esi = st0x_cr_sr, ebx = st0x_dr */
                              __asm__ (
                                          /* Test for room to read */
                                          "orl %%ecx, %%ecx\n\t"
                                          "jz 2f\n\t" "cld\n\t"
/*                "movl st0x_cr_sr, %%esi\n\t"  */
/*                "movl st0x_dr, %%ebx\n\t"  */
                                          "1:\t"
                                          "movb (%%esi), %%al\n\t"
                                          /* Test for BSY */
                                          "test $1, %%al\n\t"
                                          "jz 2f\n\t"
                                          /* Test for data in phase - STATUS & REQ_MASK should be REQ_DATAIN, 
                                             = STAT_IO, which is 4. */
                                          "movb $0xe, %%ah\n\t"
                                          "andb %%al, %%ah\n\t"
                                          "cmpb $0x04, %%ah\n\t"
                                          "jne 2f\n\t"
                                          /* Test for REQ */
                                          "test $0x10, %%al\n\t"
                                          "jz 1b\n\t"
                                          "movb (%%ebx), %%al\n\t"
                                          "stosb\n\t"
                                          "loop 1b\n\t" "2:\n"
                              /* output */ :"=D" (data), "=c" (len),
                                          "=S"
                                          (__dummy_3),
                                          "=b" (__dummy_4)
/* input */
                              :           "0" (data), "1" (len),
                                          "2" (st0x_cr_sr),
                                          "3" (st0x_dr)
/* clobbered */
                              :           "eax");
#else                   /* SEAGATE_USE_ASM */
                              while (len) {
                                    unsigned char stat;

                                    stat = STATUS;
                                    if (!(stat & STAT_BSY)
                                        || ((stat & REQ_MASK) !=
                                          REQ_DATAIN))
                                          break;
                                    if (stat & STAT_REQ) {
                                          *data++ = DATA;
                                          --len;
                                    }
                              }
#endif                        /* SEAGATE_USE_ASM */
/* SJT: End. */
#if (DEBUG & PHASE_DATAIN)
                              printk ("scsi%d: transfered -= %d\n", hostno, len);
                              transfered -= len;      /* Since we assumed all of Len got  *
                                                   transfered, correct our mistake */
#endif
                        }

                        if (!len && nobuffs) {
                              --nobuffs;
                              ++buffer;
                              len = buffer->length;
                              data = sg_virt(buffer);
                              DPRINTK (DEBUG_SG, "scsi%d : next scatter-gather buffer len = %d address = %08x\n", hostno, len, data);
                        }
                        break;

                  case REQ_CMDOUT:
                        while (((status_read = STATUS) & STAT_BSY) &&
                               ((status_read & REQ_MASK) == REQ_CMDOUT))
                              if (status_read & STAT_REQ) {
                                    WRITE_DATA (*(const unsigned char *) cmnd);
                                    cmnd = 1 + (const unsigned char *)cmnd;
#ifdef SLOW_RATE
                                    if (borken)
                                          borken_wait ();
#endif
                              }
                        break;

                  case REQ_STATIN:
                        status = DATA;
                        break;

                  case REQ_MSGOUT:
                        /*
                         *    We can only have sent a MSG OUT if we
                         *    requested to do this by raising ATTN.
                         *    So, we must drop ATTN.
                         */
                        WRITE_CONTROL (BASE_CMD | CMD_DRVR_ENABLE);
                        /*
                         *    If we are reconnecting, then we must 
                         *    send an IDENTIFY message in response
                         *    to MSGOUT.
                         */
                        switch (reselect) {
                        case CAN_RECONNECT:
                              WRITE_DATA (IDENTIFY (1, lun));
                              DPRINTK (PHASE_RESELECT | PHASE_MSGOUT, "scsi%d : sent IDENTIFY message.\n", hostno);
                              break;
#ifdef LINKED
                        case LINKED_WRONG:
                              WRITE_DATA (ABORT);
                              linked_connected = 0;
                              reselect = CAN_RECONNECT;
                              goto connect_loop;
                              DPRINTK (PHASE_MSGOUT | DEBUG_LINKED, "scsi%d : sent ABORT message to cancel incorrect I_T_L nexus.\n", hostno);
#endif                              /* LINKED */
                              DPRINTK (DEBUG_LINKED, "correct\n");
                        default:
                              WRITE_DATA (NOP);
                              printk("scsi%d : target %d requested MSGOUT, sent NOP message.\n", hostno, target);
                        }
                        break;

                  case REQ_MSGIN:
                        switch (message = DATA) {
                        case DISCONNECT:
                              DANY("seagate: deciding to disconnect\n");
                              should_reconnect = 1;
                              current_data = data;    /* WDE add */
                              current_buffer = buffer;
                              current_bufflen = len;  /* WDE add */
                              current_nobuffs = nobuffs;
#ifdef LINKED
                              linked_connected = 0;
#endif
                              done = 1;
                              DPRINTK ((PHASE_RESELECT | PHASE_MSGIN), "scsi%d : disconnected.\n", hostno);
                              break;

#ifdef LINKED
                        case LINKED_CMD_COMPLETE:
                        case LINKED_FLG_CMD_COMPLETE:
#endif
                        case COMMAND_COMPLETE:
                              /*
                               * Note : we should check for underflow here.
                               */
                              DPRINTK(PHASE_MSGIN, "scsi%d : command complete.\n", hostno);
                              done = 1;
                              break;
                        case ABORT:
                              DPRINTK(PHASE_MSGIN, "scsi%d : abort message.\n", hostno);
                              done = 1;
                              break;
                        case SAVE_POINTERS:
                              current_buffer = buffer;
                              current_bufflen = len;  /* WDE add */
                              current_data = data;    /* WDE mod */
                              current_nobuffs = nobuffs;
                              DPRINTK (PHASE_MSGIN, "scsi%d : pointers saved.\n", hostno);
                              break;
                        case RESTORE_POINTERS:
                              buffer = current_buffer;
                              cmnd = current_cmnd;
                              data = current_data;    /* WDE mod */
                              len = current_bufflen;
                              nobuffs = current_nobuffs;
                              DPRINTK(PHASE_MSGIN, "scsi%d : pointers restored.\n", hostno);
                              break;
                        default:

                              /*
                               *    IDENTIFY distinguishes itself
                               *    from the other messages by 
                               *    setting the high bit.
                               *
                               *      Note : we need to handle at 
                               *    least one outstanding command
                               *    per LUN, and need to hash the 
                               *    SCSI command for that I_T_L
                               *    nexus based on the known ID 
                               *    (at this point) and LUN.
                               */

                              if (message & 0x80) {
                                    DPRINTK (PHASE_MSGIN, "scsi%d : IDENTIFY message received from id %d, lun %d.\n", hostno, target, message & 7);
                              } else {
                                    /*
                                     *      We should go into a
                                     *    MESSAGE OUT phase, and
                                     *    send  a MESSAGE_REJECT
                                     *      if we run into a message 
                                     *    that we don't like.  The
                                     *    seagate driver needs 
                                     *    some serious 
                                     *    restructuring first
                                     *    though.
                                     */
                                    DPRINTK (PHASE_MSGIN, "scsi%d : unknown message %d from target %d.\n", hostno, message, target);
                              }
                        }
                        break;
                  default:
                        printk(KERN_ERR "scsi%d : unknown phase.\n", hostno);
                        st0x_aborted = DID_ERROR;
                  }     /* end of switch (status_read &  REQ_MASK) */
#ifdef SLOW_RATE
                  /*
                   * I really don't care to deal with borken devices in
                   * each single byte transfer case (ie, message in,
                   * message out, status), so I'll do the wait here if 
                   * necessary.
                   */
                  if(borken)
                        borken_wait();
#endif

            }           /* if(status_read & STAT_REQ) ends */
      }                 /* while(((status_read = STATUS)...) ends */

      DPRINTK(PHASE_DATAIN | PHASE_DATAOUT | PHASE_EXIT, "scsi%d : Transfered %d bytes\n", hostno, transfered);

#if (DEBUG & PHASE_EXIT)
#if 0                   /* Doesn't work for scatter/gather */
      printk("Buffer : \n");
      for(i = 0; i < 20; ++i)
            printk("%02x  ", ((unsigned char *) data)[i]);  /* WDE mod */
      printk("\n");
#endif
      printk("scsi%d : status = ", hostno);
      scsi_print_status(status);
      printk(" message = %02x\n", message);
#endif

      /* We shouldn't reach this until *after* BSY has been deasserted */

#ifdef LINKED
      else
      {
            /*
             * Fix the message byte so that unsuspecting high level drivers
             * don't puke when they see a LINKED COMMAND message in place of
             * the COMMAND COMPLETE they may be expecting.  Shouldn't be
             * necessary, but it's better to be on the safe side.
             *
             * A non LINKED* message byte will indicate that the command
             * completed, and we are now disconnected.
             */

            switch (message) {
            case LINKED_CMD_COMPLETE:
            case LINKED_FLG_CMD_COMPLETE:
                  message = COMMAND_COMPLETE;
                  linked_target = current_target;
                  linked_lun = current_lun;
                  linked_connected = 1;
                  DPRINTK (DEBUG_LINKED, "scsi%d : keeping I_T_L nexus established for linked command.\n", hostno);
                  /* We also will need to adjust status to accommodate intermediate
                     conditions. */
                  if ((status == INTERMEDIATE_GOOD) || (status == INTERMEDIATE_C_GOOD))
                        status = GOOD;
                  break;
                  /*
                   * We should also handle what are "normal" termination
                   * messages here (ABORT, BUS_DEVICE_RESET?, and
                   * COMMAND_COMPLETE individually, and flake if things
                   * aren't right.
                   */
            default:
                  DPRINTK (DEBUG_LINKED, "scsi%d : closing I_T_L nexus.\n", hostno);
                  linked_connected = 0;
            }
      }
#endif      /* LINKED */

      if (should_reconnect) {
            DPRINTK (PHASE_RESELECT, "scsi%d : exiting seagate_st0x_queue_command() with reconnect enabled.\n", hostno);
            WRITE_CONTROL (BASE_CMD | CMD_INTR);
      } else
            WRITE_CONTROL (BASE_CMD);

      return retcode (st0x_aborted);
}                       /* end of internal_command */

static int seagate_st0x_abort(struct scsi_cmnd * SCpnt)
{
      st0x_aborted = DID_ABORT;
      return SUCCESS;
}

#undef ULOOP
#undef TIMEOUT

/*
 * the seagate_st0x_reset function resets the SCSI bus 
 *
 * May be called with SCpnt = NULL
 */

static int seagate_st0x_bus_reset(struct scsi_cmnd * SCpnt)
{
      /* No timeouts - this command is going to fail because it was reset. */
      DANY ("scsi%d: Reseting bus... ", hostno);

      /* assert  RESET signal on SCSI bus.  */
      WRITE_CONTROL (BASE_CMD | CMD_RST);

      mdelay (20);

      WRITE_CONTROL (BASE_CMD);
      st0x_aborted = DID_RESET;

      DANY ("done.\n");
      return SUCCESS;
}

static int seagate_st0x_release(struct Scsi_Host *shost)
{
      if (shost->irq)
            free_irq(shost->irq, shost);
      release_region(shost->io_port, shost->n_io_port);
      return 0;
}

static struct scsi_host_template driver_template = {
      .detect           = seagate_st0x_detect,
      .release          = seagate_st0x_release,
      .info             = seagate_st0x_info,
      .queuecommand     = seagate_st0x_queue_command,
      .eh_abort_handler = seagate_st0x_abort,
      .eh_bus_reset_handler   = seagate_st0x_bus_reset,
      .can_queue        = 1,
      .this_id          = 7,
      .sg_tablesize     = SG_ALL,
      .cmd_per_lun      = 1,
      .use_clustering         = DISABLE_CLUSTERING,
};
#include "scsi_module.c"

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