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53c700.c

/* -*- mode: c; c-basic-offset: 8 -*- */

/* NCR (or Symbios) 53c700 and 53c700-66 Driver
 *
 * Copyright (C) 2001 by James.Bottomley@HansenPartnership.com
**-----------------------------------------------------------------------------
**  
**  This program is free software; you can redistribute it and/or modify
**  it under the terms of the GNU General Public License as published by
**  the Free Software Foundation; either version 2 of the License, or
**  (at your option) any later version.
**
**  This program is distributed in the hope that it will be useful,
**  but WITHOUT ANY WARRANTY; without even the implied warranty of
**  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
**  GNU General Public License for more details.
**
**  You should have received a copy of the GNU General Public License
**  along with this program; if not, write to the Free Software
**  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
**
**-----------------------------------------------------------------------------
 */

/* Notes:
 *
 * This driver is designed exclusively for these chips (virtually the
 * earliest of the scripts engine chips).  They need their own drivers
 * because they are missing so many of the scripts and snazzy register
 * features of their elder brothers (the 710, 720 and 770).
 *
 * The 700 is the lowliest of the line, it can only do async SCSI.
 * The 700-66 can at least do synchronous SCSI up to 10MHz.
 * 
 * The 700 chip has no host bus interface logic of its own.  However,
 * it is usually mapped to a location with well defined register
 * offsets.  Therefore, if you can determine the base address and the
 * irq your board incorporating this chip uses, you can probably use
 * this driver to run it (although you'll probably have to write a
 * minimal wrapper for the purpose---see the NCR_D700 driver for
 * details about how to do this).
 *
 *
 * TODO List:
 *
 * 1. Better statistics in the proc fs
 *
 * 2. Implement message queue (queues SCSI messages like commands) and make
 *    the abort and device reset functions use them.
 * */

/* CHANGELOG
 *
 * Version 2.8
 *
 * Fixed bad bug affecting tag starvation processing (previously the
 * driver would hang the system if too many tags starved.  Also fixed
 * bad bug having to do with 10 byte command processing and REQUEST
 * SENSE (the command would loop forever getting a transfer length
 * mismatch in the CMD phase).
 *
 * Version 2.7
 *
 * Fixed scripts problem which caused certain devices (notably CDRWs)
 * to hang on initial INQUIRY.  Updated NCR_700_readl/writel to use
 * __raw_readl/writel for parisc compatibility (Thomas
 * Bogendoerfer). Added missing SCp->request_bufflen initialisation
 * for sense requests (Ryan Bradetich).
 *
 * Version 2.6
 *
 * Following test of the 64 bit parisc kernel by Richard Hirst,
 * several problems have now been corrected.  Also adds support for
 * consistent memory allocation.
 *
 * Version 2.5
 * 
 * More Compatibility changes for 710 (now actually works).  Enhanced
 * support for odd clock speeds which constrain SDTR negotiations.
 * correct cacheline separation for scsi messages and status for
 * incoherent architectures.  Use of the pci mapping functions on
 * buffers to begin support for 64 bit drivers.
 *
 * Version 2.4
 *
 * Added support for the 53c710 chip (in 53c700 emulation mode only---no 
 * special 53c710 instructions or registers are used).
 *
 * Version 2.3
 *
 * More endianness/cache coherency changes.
 *
 * Better bad device handling (handles devices lying about tag
 * queueing support and devices which fail to provide sense data on
 * contingent allegiance conditions)
 *
 * Many thanks to Richard Hirst <rhirst@linuxcare.com> for patiently
 * debugging this driver on the parisc architecture and suggesting
 * many improvements and bug fixes.
 *
 * Thanks also go to Linuxcare Inc. for providing several PARISC
 * machines for me to debug the driver on.
 *
 * Version 2.2
 *
 * Made the driver mem or io mapped; added endian invariance; added
 * dma cache flushing operations for architectures which need it;
 * added support for more varied clocking speeds.
 *
 * Version 2.1
 *
 * Initial modularisation from the D700.  See NCR_D700.c for the rest of
 * the changelog.
 * */
#define NCR_700_VERSION "2.8"

#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/ioport.h>
#include <linux/delay.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
#include <linux/blkdev.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/device.h>
#include <asm/dma.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/pgtable.h>
#include <asm/byteorder.h>

#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_dbg.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_tcq.h>
#include <scsi/scsi_transport.h>
#include <scsi/scsi_transport_spi.h>

#include "53c700.h"

/* NOTE: For 64 bit drivers there are points in the code where we use
 * a non dereferenceable pointer to point to a structure in dma-able
 * memory (which is 32 bits) so that we can use all of the structure
 * operations but take the address at the end.  This macro allows us
 * to truncate the 64 bit pointer down to 32 bits without the compiler
 * complaining */
#define to32bit(x)      ((__u32)((unsigned long)(x)))

#ifdef NCR_700_DEBUG
#define STATIC
#else
#define STATIC static
#endif

MODULE_AUTHOR("James Bottomley");
MODULE_DESCRIPTION("53c700 and 53c700-66 Driver");
MODULE_LICENSE("GPL");

/* This is the script */
#include "53c700_d.h"


STATIC int NCR_700_queuecommand(struct scsi_cmnd *, void (*done)(struct scsi_cmnd *));
STATIC int NCR_700_abort(struct scsi_cmnd * SCpnt);
STATIC int NCR_700_bus_reset(struct scsi_cmnd * SCpnt);
STATIC int NCR_700_host_reset(struct scsi_cmnd * SCpnt);
STATIC void NCR_700_chip_setup(struct Scsi_Host *host);
STATIC void NCR_700_chip_reset(struct Scsi_Host *host);
STATIC int NCR_700_slave_alloc(struct scsi_device *SDpnt);
STATIC int NCR_700_slave_configure(struct scsi_device *SDpnt);
STATIC void NCR_700_slave_destroy(struct scsi_device *SDpnt);
static int NCR_700_change_queue_depth(struct scsi_device *SDpnt, int depth);
static int NCR_700_change_queue_type(struct scsi_device *SDpnt, int depth);

STATIC struct device_attribute *NCR_700_dev_attrs[];

STATIC struct scsi_transport_template *NCR_700_transport_template = NULL;

static char *NCR_700_phase[] = {
      "",
      "after selection",
      "before command phase",
      "after command phase",
      "after status phase",
      "after data in phase",
      "after data out phase",
      "during data phase",
};

static char *NCR_700_condition[] = {
      "",
      "NOT MSG_OUT",
      "UNEXPECTED PHASE",
      "NOT MSG_IN",
      "UNEXPECTED MSG",
      "MSG_IN",
      "SDTR_MSG RECEIVED",
      "REJECT_MSG RECEIVED",
      "DISCONNECT_MSG RECEIVED",
      "MSG_OUT",
      "DATA_IN",
      
};

static char *NCR_700_fatal_messages[] = {
      "unexpected message after reselection",
      "still MSG_OUT after message injection",
      "not MSG_IN after selection",
      "Illegal message length received",
};

static char *NCR_700_SBCL_bits[] = {
      "IO ",
      "CD ",
      "MSG ",
      "ATN ",
      "SEL ",
      "BSY ",
      "ACK ",
      "REQ ",
};

static char *NCR_700_SBCL_to_phase[] = {
      "DATA_OUT",
      "DATA_IN",
      "CMD_OUT",
      "STATE",
      "ILLEGAL PHASE",
      "ILLEGAL PHASE",
      "MSG OUT",
      "MSG IN",
};

/* This translates the SDTR message offset and period to a value
 * which can be loaded into the SXFER_REG.
 *
 * NOTE: According to SCSI-2, the true transfer period (in ns) is
 *       actually four times this period value */
static inline __u8
NCR_700_offset_period_to_sxfer(struct NCR_700_Host_Parameters *hostdata,
                         __u8 offset, __u8 period)
{
      int XFERP;

      __u8 min_xferp = (hostdata->chip710
                    ? NCR_710_MIN_XFERP : NCR_700_MIN_XFERP);
      __u8 max_offset = (hostdata->chip710
                     ? NCR_710_MAX_OFFSET : NCR_700_MAX_OFFSET);

      if(offset == 0)
            return 0;

      if(period < hostdata->min_period) {
            printk(KERN_WARNING "53c700: Period %dns is less than this chip's minimum, setting to %d\n", period*4, NCR_700_MIN_PERIOD*4);
            period = hostdata->min_period;
      }
      XFERP = (period*4 * hostdata->sync_clock)/1000 - 4;
      if(offset > max_offset) {
            printk(KERN_WARNING "53c700: Offset %d exceeds chip maximum, setting to %d\n",
                   offset, max_offset);
            offset = max_offset;
      }
      if(XFERP < min_xferp) {
            XFERP =  min_xferp;
      }
      return (offset & 0x0f) | (XFERP & 0x07)<<4;
}

static inline __u8
NCR_700_get_SXFER(struct scsi_device *SDp)
{
      struct NCR_700_Host_Parameters *hostdata = 
            (struct NCR_700_Host_Parameters *)SDp->host->hostdata[0];

      return NCR_700_offset_period_to_sxfer(hostdata,
                                    spi_offset(SDp->sdev_target),
                                    spi_period(SDp->sdev_target));
}

struct Scsi_Host *
NCR_700_detect(struct scsi_host_template *tpnt,
             struct NCR_700_Host_Parameters *hostdata, struct device *dev)
{
      dma_addr_t pScript, pSlots;
      __u8 *memory;
      __u32 *script;
      struct Scsi_Host *host;
      static int banner = 0;
      int j;

      if(tpnt->sdev_attrs == NULL)
            tpnt->sdev_attrs = NCR_700_dev_attrs;

      memory = dma_alloc_noncoherent(hostdata->dev, TOTAL_MEM_SIZE,
                               &pScript, GFP_KERNEL);
      if(memory == NULL) {
            printk(KERN_ERR "53c700: Failed to allocate memory for driver, detatching\n");
            return NULL;
      }

      script = (__u32 *)memory;
      hostdata->msgin = memory + MSGIN_OFFSET;
      hostdata->msgout = memory + MSGOUT_OFFSET;
      hostdata->status = memory + STATUS_OFFSET;
      /* all of these offsets are L1_CACHE_BYTES separated.  It is fatal
       * if this isn't sufficient separation to avoid dma flushing issues */
      BUG_ON(!dma_is_consistent(hostdata->dev, pScript) && L1_CACHE_BYTES < dma_get_cache_alignment());
      hostdata->slots = (struct NCR_700_command_slot *)(memory + SLOTS_OFFSET);
      hostdata->dev = dev;

      pSlots = pScript + SLOTS_OFFSET;

      /* Fill in the missing routines from the host template */
      tpnt->queuecommand = NCR_700_queuecommand;
      tpnt->eh_abort_handler = NCR_700_abort;
      tpnt->eh_bus_reset_handler = NCR_700_bus_reset;
      tpnt->eh_host_reset_handler = NCR_700_host_reset;
      tpnt->can_queue = NCR_700_COMMAND_SLOTS_PER_HOST;
      tpnt->sg_tablesize = NCR_700_SG_SEGMENTS;
      tpnt->cmd_per_lun = NCR_700_CMD_PER_LUN;
      tpnt->use_clustering = ENABLE_CLUSTERING;
      tpnt->slave_configure = NCR_700_slave_configure;
      tpnt->slave_destroy = NCR_700_slave_destroy;
      tpnt->slave_alloc = NCR_700_slave_alloc;
      tpnt->change_queue_depth = NCR_700_change_queue_depth;
      tpnt->change_queue_type = NCR_700_change_queue_type;

      if(tpnt->name == NULL)
            tpnt->name = "53c700";
      if(tpnt->proc_name == NULL)
            tpnt->proc_name = "53c700";

      host = scsi_host_alloc(tpnt, 4);
      if (!host)
            return NULL;
      memset(hostdata->slots, 0, sizeof(struct NCR_700_command_slot)
             * NCR_700_COMMAND_SLOTS_PER_HOST);
      for (j = 0; j < NCR_700_COMMAND_SLOTS_PER_HOST; j++) {
            dma_addr_t offset = (dma_addr_t)((unsigned long)&hostdata->slots[j].SG[0]
                                - (unsigned long)&hostdata->slots[0].SG[0]);
            hostdata->slots[j].pSG = (struct NCR_700_SG_List *)((unsigned long)(pSlots + offset));
            if(j == 0)
                  hostdata->free_list = &hostdata->slots[j];
            else
                  hostdata->slots[j-1].ITL_forw = &hostdata->slots[j];
            hostdata->slots[j].state = NCR_700_SLOT_FREE;
      }

      for (j = 0; j < ARRAY_SIZE(SCRIPT); j++)
            script[j] = bS_to_host(SCRIPT[j]);

      /* adjust all labels to be bus physical */
      for (j = 0; j < PATCHES; j++)
            script[LABELPATCHES[j]] = bS_to_host(pScript + SCRIPT[LABELPATCHES[j]]);
      /* now patch up fixed addresses. */
      script_patch_32(hostdata->dev, script, MessageLocation,
                  pScript + MSGOUT_OFFSET);
      script_patch_32(hostdata->dev, script, StatusAddress,
                  pScript + STATUS_OFFSET);
      script_patch_32(hostdata->dev, script, ReceiveMsgAddress,
                  pScript + MSGIN_OFFSET);

      hostdata->script = script;
      hostdata->pScript = pScript;
      dma_sync_single_for_device(hostdata->dev, pScript, sizeof(SCRIPT), DMA_TO_DEVICE);
      hostdata->state = NCR_700_HOST_FREE;
      hostdata->cmd = NULL;
      host->max_id = 8;
      host->max_lun = NCR_700_MAX_LUNS;
      BUG_ON(NCR_700_transport_template == NULL);
      host->transportt = NCR_700_transport_template;
      host->unique_id = (unsigned long)hostdata->base;
      hostdata->eh_complete = NULL;
      host->hostdata[0] = (unsigned long)hostdata;
      /* kick the chip */
      NCR_700_writeb(0xff, host, CTEST9_REG);
      if (hostdata->chip710)
            hostdata->rev = (NCR_700_readb(host, CTEST8_REG)>>4) & 0x0f;
      else
            hostdata->rev = (NCR_700_readb(host, CTEST7_REG)>>4) & 0x0f;
      hostdata->fast = (NCR_700_readb(host, CTEST9_REG) == 0);
      if (banner == 0) {
            printk(KERN_NOTICE "53c700: Version " NCR_700_VERSION " By James.Bottomley@HansenPartnership.com\n");
            banner = 1;
      }
      printk(KERN_NOTICE "scsi%d: %s rev %d %s\n", host->host_no,
             hostdata->chip710 ? "53c710" :
             (hostdata->fast ? "53c700-66" : "53c700"),
             hostdata->rev, hostdata->differential ?
             "(Differential)" : "");
      /* reset the chip */
      NCR_700_chip_reset(host);

      if (scsi_add_host(host, dev)) {
            dev_printk(KERN_ERR, dev, "53c700: scsi_add_host failed\n");
            scsi_host_put(host);
            return NULL;
      }

      spi_signalling(host) = hostdata->differential ? SPI_SIGNAL_HVD :
            SPI_SIGNAL_SE;

      return host;
}

int
NCR_700_release(struct Scsi_Host *host)
{
      struct NCR_700_Host_Parameters *hostdata = 
            (struct NCR_700_Host_Parameters *)host->hostdata[0];

      dma_free_noncoherent(hostdata->dev, TOTAL_MEM_SIZE,
                         hostdata->script, hostdata->pScript);
      return 1;
}

static inline __u8
NCR_700_identify(int can_disconnect, __u8 lun)
{
      return IDENTIFY_BASE |
            ((can_disconnect) ? 0x40 : 0) |
            (lun & NCR_700_LUN_MASK);
}

/*
 * Function : static int data_residual (Scsi_Host *host)
 *
 * Purpose : return residual data count of what's in the chip.  If you
 * really want to know what this function is doing, it's almost a
 * direct transcription of the algorithm described in the 53c710
 * guide, except that the DBC and DFIFO registers are only 6 bits
 * wide on a 53c700.
 *
 * Inputs : host - SCSI host */
static inline int
NCR_700_data_residual (struct Scsi_Host *host) {
      struct NCR_700_Host_Parameters *hostdata = 
            (struct NCR_700_Host_Parameters *)host->hostdata[0];
      int count, synchronous = 0;
      unsigned int ddir;

      if(hostdata->chip710) {
            count = ((NCR_700_readb(host, DFIFO_REG) & 0x7f) -
                   (NCR_700_readl(host, DBC_REG) & 0x7f)) & 0x7f;
      } else {
            count = ((NCR_700_readb(host, DFIFO_REG) & 0x3f) -
                   (NCR_700_readl(host, DBC_REG) & 0x3f)) & 0x3f;
      }
      
      if(hostdata->fast)
            synchronous = NCR_700_readb(host, SXFER_REG) & 0x0f;
      
      /* get the data direction */
      ddir = NCR_700_readb(host, CTEST0_REG) & 0x01;

      if (ddir) {
            /* Receive */
            if (synchronous) 
                  count += (NCR_700_readb(host, SSTAT2_REG) & 0xf0) >> 4;
            else
                  if (NCR_700_readb(host, SSTAT1_REG) & SIDL_REG_FULL)
                        ++count;
      } else {
            /* Send */
            __u8 sstat = NCR_700_readb(host, SSTAT1_REG);
            if (sstat & SODL_REG_FULL)
                  ++count;
            if (synchronous && (sstat & SODR_REG_FULL))
                  ++count;
      }
#ifdef NCR_700_DEBUG
      if(count)
            printk("RESIDUAL IS %d (ddir %d)\n", count, ddir);
#endif
      return count;
}

/* print out the SCSI wires and corresponding phase from the SBCL register
 * in the chip */
static inline char *
sbcl_to_string(__u8 sbcl)
{
      int i;
      static char ret[256];

      ret[0]='\0';
      for(i=0; i<8; i++) {
            if((1<<i) & sbcl) 
                  strcat(ret, NCR_700_SBCL_bits[i]);
      }
      strcat(ret, NCR_700_SBCL_to_phase[sbcl & 0x07]);
      return ret;
}

static inline __u8
bitmap_to_number(__u8 bitmap)
{
      __u8 i;

      for(i=0; i<8 && !(bitmap &(1<<i)); i++)
            ;
      return i;
}

/* Pull a slot off the free list */
STATIC struct NCR_700_command_slot *
find_empty_slot(struct NCR_700_Host_Parameters *hostdata)
{
      struct NCR_700_command_slot *slot = hostdata->free_list;

      if(slot == NULL) {
            /* sanity check */
            if(hostdata->command_slot_count != NCR_700_COMMAND_SLOTS_PER_HOST)
                  printk(KERN_ERR "SLOTS FULL, but count is %d, should be %d\n", hostdata->command_slot_count, NCR_700_COMMAND_SLOTS_PER_HOST);
            return NULL;
      }

      if(slot->state != NCR_700_SLOT_FREE)
            /* should panic! */
            printk(KERN_ERR "BUSY SLOT ON FREE LIST!!!\n");
            

      hostdata->free_list = slot->ITL_forw;
      slot->ITL_forw = NULL;


      /* NOTE: set the state to busy here, not queued, since this
       * indicates the slot is in use and cannot be run by the IRQ
       * finish routine.  If we cannot queue the command when it
       * is properly build, we then change to NCR_700_SLOT_QUEUED */
      slot->state = NCR_700_SLOT_BUSY;
      slot->flags = 0;
      hostdata->command_slot_count++;
      
      return slot;
}

STATIC void 
free_slot(struct NCR_700_command_slot *slot,
        struct NCR_700_Host_Parameters *hostdata)
{
      if((slot->state & NCR_700_SLOT_MASK) != NCR_700_SLOT_MAGIC) {
            printk(KERN_ERR "53c700: SLOT %p is not MAGIC!!!\n", slot);
      }
      if(slot->state == NCR_700_SLOT_FREE) {
            printk(KERN_ERR "53c700: SLOT %p is FREE!!!\n", slot);
      }
      
      slot->resume_offset = 0;
      slot->cmnd = NULL;
      slot->state = NCR_700_SLOT_FREE;
      slot->ITL_forw = hostdata->free_list;
      hostdata->free_list = slot;
      hostdata->command_slot_count--;
}


/* This routine really does very little.  The command is indexed on
   the ITL and (if tagged) the ITLQ lists in _queuecommand */
STATIC void
save_for_reselection(struct NCR_700_Host_Parameters *hostdata,
                 struct scsi_cmnd *SCp, __u32 dsp)
{
      /* Its just possible that this gets executed twice */
      if(SCp != NULL) {
            struct NCR_700_command_slot *slot =
                  (struct NCR_700_command_slot *)SCp->host_scribble;

            slot->resume_offset = dsp;
      }
      hostdata->state = NCR_700_HOST_FREE;
      hostdata->cmd = NULL;
}

STATIC inline void
NCR_700_unmap(struct NCR_700_Host_Parameters *hostdata, struct scsi_cmnd *SCp,
            struct NCR_700_command_slot *slot)
{
      if(SCp->sc_data_direction != DMA_NONE &&
         SCp->sc_data_direction != DMA_BIDIRECTIONAL)
            scsi_dma_unmap(SCp);
}

STATIC inline void
NCR_700_scsi_done(struct NCR_700_Host_Parameters *hostdata,
             struct scsi_cmnd *SCp, int result)
{
      hostdata->state = NCR_700_HOST_FREE;
      hostdata->cmd = NULL;

      if(SCp != NULL) {
            struct NCR_700_command_slot *slot = 
                  (struct NCR_700_command_slot *)SCp->host_scribble;
            
            dma_unmap_single(hostdata->dev, slot->pCmd,
                         sizeof(SCp->cmnd), DMA_TO_DEVICE);
            if (slot->flags == NCR_700_FLAG_AUTOSENSE) {
                  char *cmnd = NCR_700_get_sense_cmnd(SCp->device);
#ifdef NCR_700_DEBUG
                  printk(" ORIGINAL CMD %p RETURNED %d, new return is %d sense is\n",
                         SCp, SCp->cmnd[7], result);
                  scsi_print_sense("53c700", SCp);

#endif
                  dma_unmap_single(hostdata->dev, slot->dma_handle, sizeof(SCp->sense_buffer), DMA_FROM_DEVICE);
                  /* restore the old result if the request sense was
                   * successful */
                  if (result == 0)
                        result = cmnd[7];
                  /* restore the original length */
                  SCp->cmd_len = cmnd[8];
            } else
                  NCR_700_unmap(hostdata, SCp, slot);

            free_slot(slot, hostdata);
#ifdef NCR_700_DEBUG
            if(NCR_700_get_depth(SCp->device) == 0 ||
               NCR_700_get_depth(SCp->device) > SCp->device->queue_depth)
                  printk(KERN_ERR "Invalid depth in NCR_700_scsi_done(): %d\n",
                         NCR_700_get_depth(SCp->device));
#endif /* NCR_700_DEBUG */
            NCR_700_set_depth(SCp->device, NCR_700_get_depth(SCp->device) - 1);

            SCp->host_scribble = NULL;
            SCp->result = result;
            SCp->scsi_done(SCp);
      } else {
            printk(KERN_ERR "53c700: SCSI DONE HAS NULL SCp\n");
      }
}


STATIC void
NCR_700_internal_bus_reset(struct Scsi_Host *host)
{
      /* Bus reset */
      NCR_700_writeb(ASSERT_RST, host, SCNTL1_REG);
      udelay(50);
      NCR_700_writeb(0, host, SCNTL1_REG);

}

STATIC void
NCR_700_chip_setup(struct Scsi_Host *host)
{
      struct NCR_700_Host_Parameters *hostdata = 
            (struct NCR_700_Host_Parameters *)host->hostdata[0];
      __u8 min_period;
      __u8 min_xferp = (hostdata->chip710 ? NCR_710_MIN_XFERP : NCR_700_MIN_XFERP);

      if(hostdata->chip710) {
            __u8 burst_disable = 0;
            __u8 burst_length = 0;

            switch (hostdata->burst_length) {
                  case 1:
                          burst_length = BURST_LENGTH_1;
                          break;
                  case 2:
                          burst_length = BURST_LENGTH_2;
                          break;
                  case 4:
                          burst_length = BURST_LENGTH_4;
                          break;
                  case 8:
                          burst_length = BURST_LENGTH_8;
                          break;
                  default:
                          burst_disable = BURST_DISABLE;
                          break;
            }
            hostdata->dcntl_extra |= COMPAT_700_MODE;

            NCR_700_writeb(hostdata->dcntl_extra, host, DCNTL_REG);
            NCR_700_writeb(burst_length | hostdata->dmode_extra,
                         host, DMODE_710_REG);
            NCR_700_writeb(burst_disable | hostdata->ctest7_extra |
                         (hostdata->differential ? DIFF : 0),
                         host, CTEST7_REG);
            NCR_700_writeb(BTB_TIMER_DISABLE, host, CTEST0_REG);
            NCR_700_writeb(FULL_ARBITRATION | ENABLE_PARITY | PARITY
                         | AUTO_ATN, host, SCNTL0_REG);
      } else {
            NCR_700_writeb(BURST_LENGTH_8 | hostdata->dmode_extra,
                         host, DMODE_700_REG);
            NCR_700_writeb(hostdata->differential ? 
                         DIFF : 0, host, CTEST7_REG);
            if(hostdata->fast) {
                  /* this is for 700-66, does nothing on 700 */
                  NCR_700_writeb(LAST_DIS_ENBL | ENABLE_ACTIVE_NEGATION 
                               | GENERATE_RECEIVE_PARITY, host,
                               CTEST8_REG);
            } else {
                  NCR_700_writeb(FULL_ARBITRATION | ENABLE_PARITY
                               | PARITY | AUTO_ATN, host, SCNTL0_REG);
            }
      }

      NCR_700_writeb(1 << host->this_id, host, SCID_REG);
      NCR_700_writeb(0, host, SBCL_REG);
      NCR_700_writeb(ASYNC_OPERATION, host, SXFER_REG);

      NCR_700_writeb(PHASE_MM_INT | SEL_TIMEOUT_INT | GROSS_ERR_INT | UX_DISC_INT
           | RST_INT | PAR_ERR_INT | SELECT_INT, host, SIEN_REG);

      NCR_700_writeb(ABORT_INT | INT_INST_INT | ILGL_INST_INT, host, DIEN_REG);
      NCR_700_writeb(ENABLE_SELECT, host, SCNTL1_REG);
      if(hostdata->clock > 75) {
            printk(KERN_ERR "53c700: Clock speed %dMHz is too high: 75Mhz is the maximum this chip can be driven at\n", hostdata->clock);
            /* do the best we can, but the async clock will be out
             * of spec: sync divider 2, async divider 3 */
            DEBUG(("53c700: sync 2 async 3\n"));
            NCR_700_writeb(SYNC_DIV_2_0, host, SBCL_REG);
            NCR_700_writeb(ASYNC_DIV_3_0 | hostdata->dcntl_extra, host, DCNTL_REG);
            hostdata->sync_clock = hostdata->clock/2;
      } else      if(hostdata->clock > 50  && hostdata->clock <= 75) {
            /* sync divider 1.5, async divider 3 */
            DEBUG(("53c700: sync 1.5 async 3\n"));
            NCR_700_writeb(SYNC_DIV_1_5, host, SBCL_REG);
            NCR_700_writeb(ASYNC_DIV_3_0 | hostdata->dcntl_extra, host, DCNTL_REG);
            hostdata->sync_clock = hostdata->clock*2;
            hostdata->sync_clock /= 3;
            
      } else if(hostdata->clock > 37 && hostdata->clock <= 50) {
            /* sync divider 1, async divider 2 */
            DEBUG(("53c700: sync 1 async 2\n"));
            NCR_700_writeb(SYNC_DIV_1_0, host, SBCL_REG);
            NCR_700_writeb(ASYNC_DIV_2_0 | hostdata->dcntl_extra, host, DCNTL_REG);
            hostdata->sync_clock = hostdata->clock;
      } else if(hostdata->clock > 25 && hostdata->clock <=37) {
            /* sync divider 1, async divider 1.5 */
            DEBUG(("53c700: sync 1 async 1.5\n"));
            NCR_700_writeb(SYNC_DIV_1_0, host, SBCL_REG);
            NCR_700_writeb(ASYNC_DIV_1_5 | hostdata->dcntl_extra, host, DCNTL_REG);
            hostdata->sync_clock = hostdata->clock;
      } else {
            DEBUG(("53c700: sync 1 async 1\n"));
            NCR_700_writeb(SYNC_DIV_1_0, host, SBCL_REG);
            NCR_700_writeb(ASYNC_DIV_1_0 | hostdata->dcntl_extra, host, DCNTL_REG);
            /* sync divider 1, async divider 1 */
            hostdata->sync_clock = hostdata->clock;
      }
      /* Calculate the actual minimum period that can be supported
       * by our synchronous clock speed.  See the 710 manual for
       * exact details of this calculation which is based on a
       * setting of the SXFER register */
      min_period = 1000*(4+min_xferp)/(4*hostdata->sync_clock);
      hostdata->min_period = NCR_700_MIN_PERIOD;
      if(min_period > NCR_700_MIN_PERIOD)
            hostdata->min_period = min_period;
}

STATIC void
NCR_700_chip_reset(struct Scsi_Host *host)
{
      struct NCR_700_Host_Parameters *hostdata = 
            (struct NCR_700_Host_Parameters *)host->hostdata[0];
      if(hostdata->chip710) {
            NCR_700_writeb(SOFTWARE_RESET_710, host, ISTAT_REG);
            udelay(100);

            NCR_700_writeb(0, host, ISTAT_REG);
      } else {
            NCR_700_writeb(SOFTWARE_RESET, host, DCNTL_REG);
            udelay(100);
            
            NCR_700_writeb(0, host, DCNTL_REG);
      }

      mdelay(1000);

      NCR_700_chip_setup(host);
}

/* The heart of the message processing engine is that the instruction
 * immediately after the INT is the normal case (and so must be CLEAR
 * ACK).  If we want to do something else, we call that routine in
 * scripts and set temp to be the normal case + 8 (skipping the CLEAR
 * ACK) so that the routine returns correctly to resume its activity
 * */
STATIC __u32
process_extended_message(struct Scsi_Host *host, 
                   struct NCR_700_Host_Parameters *hostdata,
                   struct scsi_cmnd *SCp, __u32 dsp, __u32 dsps)
{
      __u32 resume_offset = dsp, temp = dsp + 8;
      __u8 pun = 0xff, lun = 0xff;

      if(SCp != NULL) {
            pun = SCp->device->id;
            lun = SCp->device->lun;
      }

      switch(hostdata->msgin[2]) {
      case A_SDTR_MSG:
            if(SCp != NULL && NCR_700_is_flag_set(SCp->device, NCR_700_DEV_BEGIN_SYNC_NEGOTIATION)) {
                  struct scsi_target *starget = SCp->device->sdev_target;
                  __u8 period = hostdata->msgin[3];
                  __u8 offset = hostdata->msgin[4];

                  if(offset == 0 || period == 0) {
                        offset = 0;
                        period = 0;
                  }

                  spi_offset(starget) = offset;
                  spi_period(starget) = period;
                  
                  if(NCR_700_is_flag_set(SCp->device, NCR_700_DEV_PRINT_SYNC_NEGOTIATION)) {
                        spi_display_xfer_agreement(starget);
                        NCR_700_clear_flag(SCp->device, NCR_700_DEV_PRINT_SYNC_NEGOTIATION);
                  }
                  
                  NCR_700_set_flag(SCp->device, NCR_700_DEV_NEGOTIATED_SYNC);
                  NCR_700_clear_flag(SCp->device, NCR_700_DEV_BEGIN_SYNC_NEGOTIATION);
                  
                  NCR_700_writeb(NCR_700_get_SXFER(SCp->device),
                               host, SXFER_REG);

            } else {
                  /* SDTR message out of the blue, reject it */
                  shost_printk(KERN_WARNING, host,
                        "Unexpected SDTR msg\n");
                  hostdata->msgout[0] = A_REJECT_MSG;
                  dma_cache_sync(hostdata->dev, hostdata->msgout, 1, DMA_TO_DEVICE);
                  script_patch_16(hostdata->dev, hostdata->script,
                                  MessageCount, 1);
                  /* SendMsgOut returns, so set up the return
                   * address */
                  resume_offset = hostdata->pScript + Ent_SendMessageWithATN;
            }
            break;
      
      case A_WDTR_MSG:
            printk(KERN_INFO "scsi%d: (%d:%d), Unsolicited WDTR after CMD, Rejecting\n",
                   host->host_no, pun, lun);
            hostdata->msgout[0] = A_REJECT_MSG;
            dma_cache_sync(hostdata->dev, hostdata->msgout, 1, DMA_TO_DEVICE);
            script_patch_16(hostdata->dev, hostdata->script, MessageCount,
                            1);
            resume_offset = hostdata->pScript + Ent_SendMessageWithATN;

            break;

      default:
            printk(KERN_INFO "scsi%d (%d:%d): Unexpected message %s: ",
                   host->host_no, pun, lun,
                   NCR_700_phase[(dsps & 0xf00) >> 8]);
            spi_print_msg(hostdata->msgin);
            printk("\n");
            /* just reject it */
            hostdata->msgout[0] = A_REJECT_MSG;
            dma_cache_sync(hostdata->dev, hostdata->msgout, 1, DMA_TO_DEVICE);
            script_patch_16(hostdata->dev, hostdata->script, MessageCount,
                            1);
            /* SendMsgOut returns, so set up the return
             * address */
            resume_offset = hostdata->pScript + Ent_SendMessageWithATN;
      }
      NCR_700_writel(temp, host, TEMP_REG);
      return resume_offset;
}

STATIC __u32
process_message(struct Scsi_Host *host,   struct NCR_700_Host_Parameters *hostdata,
            struct scsi_cmnd *SCp, __u32 dsp, __u32 dsps)
{
      /* work out where to return to */
      __u32 temp = dsp + 8, resume_offset = dsp;
      __u8 pun = 0xff, lun = 0xff;

      if(SCp != NULL) {
            pun = SCp->device->id;
            lun = SCp->device->lun;
      }

#ifdef NCR_700_DEBUG
      printk("scsi%d (%d:%d): message %s: ", host->host_no, pun, lun,
             NCR_700_phase[(dsps & 0xf00) >> 8]);
      spi_print_msg(hostdata->msgin);
      printk("\n");
#endif

      switch(hostdata->msgin[0]) {

      case A_EXTENDED_MSG:
            resume_offset =  process_extended_message(host, hostdata, SCp,
                                            dsp, dsps);
            break;

      case A_REJECT_MSG:
            if(SCp != NULL && NCR_700_is_flag_set(SCp->device, NCR_700_DEV_BEGIN_SYNC_NEGOTIATION)) {
                  /* Rejected our sync negotiation attempt */
                  spi_period(SCp->device->sdev_target) =
                        spi_offset(SCp->device->sdev_target) = 0;
                  NCR_700_set_flag(SCp->device, NCR_700_DEV_NEGOTIATED_SYNC);
                  NCR_700_clear_flag(SCp->device, NCR_700_DEV_BEGIN_SYNC_NEGOTIATION);
            } else if(SCp != NULL && NCR_700_get_tag_neg_state(SCp->device) == NCR_700_DURING_TAG_NEGOTIATION) {
                  /* rejected our first simple tag message */
                  scmd_printk(KERN_WARNING, SCp,
                        "Rejected first tag queue attempt, turning off tag queueing\n");
                  /* we're done negotiating */
                  NCR_700_set_tag_neg_state(SCp->device, NCR_700_FINISHED_TAG_NEGOTIATION);
                  hostdata->tag_negotiated &= ~(1<<scmd_id(SCp));
                  SCp->device->tagged_supported = 0;
                  scsi_deactivate_tcq(SCp->device, host->cmd_per_lun);
            } else {
                  shost_printk(KERN_WARNING, host,
                        "(%d:%d) Unexpected REJECT Message %s\n",
                         pun, lun,
                         NCR_700_phase[(dsps & 0xf00) >> 8]);
                  /* however, just ignore it */
            }
            break;

      case A_PARITY_ERROR_MSG:
            printk(KERN_ERR "scsi%d (%d:%d) Parity Error!\n", host->host_no,
                   pun, lun);
            NCR_700_internal_bus_reset(host);
            break;
      case A_SIMPLE_TAG_MSG:
            printk(KERN_INFO "scsi%d (%d:%d) SIMPLE TAG %d %s\n", host->host_no,
                   pun, lun, hostdata->msgin[1],
                   NCR_700_phase[(dsps & 0xf00) >> 8]);
            /* just ignore it */
            break;
      default:
            printk(KERN_INFO "scsi%d (%d:%d): Unexpected message %s: ",
                   host->host_no, pun, lun,
                   NCR_700_phase[(dsps & 0xf00) >> 8]);

            spi_print_msg(hostdata->msgin);
            printk("\n");
            /* just reject it */
            hostdata->msgout[0] = A_REJECT_MSG;
            dma_cache_sync(hostdata->dev, hostdata->msgout, 1, DMA_TO_DEVICE);
            script_patch_16(hostdata->dev, hostdata->script, MessageCount,
                            1);
            /* SendMsgOut returns, so set up the return
             * address */
            resume_offset = hostdata->pScript + Ent_SendMessageWithATN;

            break;
      }
      NCR_700_writel(temp, host, TEMP_REG);
      /* set us up to receive another message */
      dma_cache_sync(hostdata->dev, hostdata->msgin, MSG_ARRAY_SIZE, DMA_FROM_DEVICE);
      return resume_offset;
}

STATIC __u32
process_script_interrupt(__u32 dsps, __u32 dsp, struct scsi_cmnd *SCp,
                   struct Scsi_Host *host,
                   struct NCR_700_Host_Parameters *hostdata)
{
      __u32 resume_offset = 0;
      __u8 pun = 0xff, lun=0xff;

      if(SCp != NULL) {
            pun = SCp->device->id;
            lun = SCp->device->lun;
      }

      if(dsps == A_GOOD_STATUS_AFTER_STATUS) {
            DEBUG(("  COMMAND COMPLETE, status=%02x\n",
                   hostdata->status[0]));
            /* OK, if TCQ still under negotiation, we now know it works */
            if (NCR_700_get_tag_neg_state(SCp->device) == NCR_700_DURING_TAG_NEGOTIATION)
                  NCR_700_set_tag_neg_state(SCp->device,
                                      NCR_700_FINISHED_TAG_NEGOTIATION);
                  
            /* check for contingent allegiance contitions */
            if(status_byte(hostdata->status[0]) == CHECK_CONDITION ||
               status_byte(hostdata->status[0]) == COMMAND_TERMINATED) {
                  struct NCR_700_command_slot *slot =
                        (struct NCR_700_command_slot *)SCp->host_scribble;
                  if(slot->flags == NCR_700_FLAG_AUTOSENSE) {
                        /* OOPS: bad device, returning another
                         * contingent allegiance condition */
                        scmd_printk(KERN_ERR, SCp,
                              "broken device is looping in contingent allegiance: ignoring\n");
                        NCR_700_scsi_done(hostdata, SCp, hostdata->status[0]);
                  } else {
                        char *cmnd =
                              NCR_700_get_sense_cmnd(SCp->device);
#ifdef NCR_DEBUG
                        scsi_print_command(SCp);
                        printk("  cmd %p has status %d, requesting sense\n",
                               SCp, hostdata->status[0]);
#endif
                        /* we can destroy the command here
                         * because the contingent allegiance
                         * condition will cause a retry which
                         * will re-copy the command from the
                         * saved data_cmnd.  We also unmap any
                         * data associated with the command
                         * here */
                        NCR_700_unmap(hostdata, SCp, slot);
                        dma_unmap_single(hostdata->dev, slot->pCmd,
                                     sizeof(SCp->cmnd),
                                     DMA_TO_DEVICE);

                        cmnd[0] = REQUEST_SENSE;
                        cmnd[1] = (SCp->device->lun & 0x7) << 5;
                        cmnd[2] = 0;
                        cmnd[3] = 0;
                        cmnd[4] = sizeof(SCp->sense_buffer);
                        cmnd[5] = 0;
                        /* Here's a quiet hack: the
                         * REQUEST_SENSE command is six bytes,
                         * so store a flag indicating that
                         * this was an internal sense request
                         * and the original status at the end
                         * of the command */
                        cmnd[6] = NCR_700_INTERNAL_SENSE_MAGIC;
                        cmnd[7] = hostdata->status[0];
                        cmnd[8] = SCp->cmd_len;
                        SCp->cmd_len = 6; /* command length for
                                       * REQUEST_SENSE */
                        slot->pCmd = dma_map_single(hostdata->dev, cmnd, MAX_COMMAND_SIZE, DMA_TO_DEVICE);
                        slot->dma_handle = dma_map_single(hostdata->dev, SCp->sense_buffer, sizeof(SCp->sense_buffer), DMA_FROM_DEVICE);
                        slot->SG[0].ins = bS_to_host(SCRIPT_MOVE_DATA_IN | sizeof(SCp->sense_buffer));
                        slot->SG[0].pAddr = bS_to_host(slot->dma_handle);
                        slot->SG[1].ins = bS_to_host(SCRIPT_RETURN);
                        slot->SG[1].pAddr = 0;
                        slot->resume_offset = hostdata->pScript;
                        dma_cache_sync(hostdata->dev, slot->SG, sizeof(slot->SG[0])*2, DMA_TO_DEVICE);
                        dma_cache_sync(hostdata->dev, SCp->sense_buffer, sizeof(SCp->sense_buffer), DMA_FROM_DEVICE);

                        /* queue the command for reissue */
                        slot->state = NCR_700_SLOT_QUEUED;
                        slot->flags = NCR_700_FLAG_AUTOSENSE;
                        hostdata->state = NCR_700_HOST_FREE;
                        hostdata->cmd = NULL;
                  }
            } else {
                  // Currently rely on the mid layer evaluation
                  // of the tag queuing capability
                  //
                  //if(status_byte(hostdata->status[0]) == GOOD &&
                  //   SCp->cmnd[0] == INQUIRY && SCp->use_sg == 0) {
                  //    /* Piggy back the tag queueing support
                  //     * on this command */
                  //    dma_sync_single_for_cpu(hostdata->dev,
                  //                    slot->dma_handle,
                  //                    SCp->request_bufflen,
                  //                    DMA_FROM_DEVICE);
                  //    if(((char *)SCp->request_buffer)[7] & 0x02) {
                  //          scmd_printk(KERN_INFO, SCp,
                  //               "Enabling Tag Command Queuing\n");
                  //          hostdata->tag_negotiated |= (1<<scmd_id(SCp));
                  //          NCR_700_set_flag(SCp->device, NCR_700_DEV_BEGIN_TAG_QUEUEING);
                  //    } else {
                  //          NCR_700_clear_flag(SCp->device, NCR_700_DEV_BEGIN_TAG_QUEUEING);
                  //          hostdata->tag_negotiated &= ~(1<<scmd_id(SCp));
                  //    }
                  //}
                  NCR_700_scsi_done(hostdata, SCp, hostdata->status[0]);
            }
      } else if((dsps & 0xfffff0f0) == A_UNEXPECTED_PHASE) {
            __u8 i = (dsps & 0xf00) >> 8;

            scmd_printk(KERN_ERR, SCp, "UNEXPECTED PHASE %s (%s)\n",
                   NCR_700_phase[i],
                   sbcl_to_string(NCR_700_readb(host, SBCL_REG)));
            scmd_printk(KERN_ERR, SCp, "         len = %d, cmd =",
                  SCp->cmd_len);
            scsi_print_command(SCp);

            NCR_700_internal_bus_reset(host);
      } else if((dsps & 0xfffff000) == A_FATAL) {
            int i = (dsps & 0xfff);

            printk(KERN_ERR "scsi%d: (%d:%d) FATAL ERROR: %s\n",
                   host->host_no, pun, lun, NCR_700_fatal_messages[i]);
            if(dsps == A_FATAL_ILLEGAL_MSG_LENGTH) {
                  printk(KERN_ERR "     msg begins %02x %02x\n",
                         hostdata->msgin[0], hostdata->msgin[1]);
            }
            NCR_700_internal_bus_reset(host);
      } else if((dsps & 0xfffff0f0) == A_DISCONNECT) {
#ifdef NCR_700_DEBUG
            __u8 i = (dsps & 0xf00) >> 8;

            printk("scsi%d: (%d:%d), DISCONNECTED (%d) %s\n",
                   host->host_no, pun, lun,
                   i, NCR_700_phase[i]);
#endif
            save_for_reselection(hostdata, SCp, dsp);

      } else if(dsps == A_RESELECTION_IDENTIFIED) {
            __u8 lun;
            struct NCR_700_command_slot *slot;
            __u8 reselection_id = hostdata->reselection_id;
            struct scsi_device *SDp;

            lun = hostdata->msgin[0] & 0x1f;

            hostdata->reselection_id = 0xff;
            DEBUG(("scsi%d: (%d:%d) RESELECTED!\n",
                   host->host_no, reselection_id, lun));
            /* clear the reselection indicator */
            SDp = __scsi_device_lookup(host, 0, reselection_id, lun);
            if(unlikely(SDp == NULL)) {
                  printk(KERN_ERR "scsi%d: (%d:%d) HAS NO device\n",
                         host->host_no, reselection_id, lun);
                  BUG();
            }
            if(hostdata->msgin[1] == A_SIMPLE_TAG_MSG) {
                  struct scsi_cmnd *SCp = scsi_find_tag(SDp, hostdata->msgin[2]);
                  if(unlikely(SCp == NULL)) {
                        printk(KERN_ERR "scsi%d: (%d:%d) no saved request for tag %d\n", 
                               host->host_no, reselection_id, lun, hostdata->msgin[2]);
                        BUG();
                  }

                  slot = (struct NCR_700_command_slot *)SCp->host_scribble;
                  DDEBUG(KERN_DEBUG, SDp,
                        "reselection is tag %d, slot %p(%d)\n",
                        hostdata->msgin[2], slot, slot->tag);
            } else {
                  struct scsi_cmnd *SCp = scsi_find_tag(SDp, SCSI_NO_TAG);
                  if(unlikely(SCp == NULL)) {
                        sdev_printk(KERN_ERR, SDp,
                              "no saved request for untagged cmd\n");
                        BUG();
                  }
                  slot = (struct NCR_700_command_slot *)SCp->host_scribble;
            }

            if(slot == NULL) {
                  printk(KERN_ERR "scsi%d: (%d:%d) RESELECTED but no saved command (MSG = %02x %02x %02x)!!\n",
                         host->host_no, reselection_id, lun,
                         hostdata->msgin[0], hostdata->msgin[1],
                         hostdata->msgin[2]);
            } else {
                  if(hostdata->state != NCR_700_HOST_BUSY)
                        printk(KERN_ERR "scsi%d: FATAL, host not busy during valid reselection!\n",
                               host->host_no);
                  resume_offset = slot->resume_offset;
                  hostdata->cmd = slot->cmnd;

                  /* re-patch for this command */
                  script_patch_32_abs(hostdata->dev, hostdata->script,
                                      CommandAddress, slot->pCmd);
                  script_patch_16(hostdata->dev, hostdata->script,
                              CommandCount, slot->cmnd->cmd_len);
                  script_patch_32_abs(hostdata->dev, hostdata->script,
                                      SGScriptStartAddress,
                                  to32bit(&slot->pSG[0].ins));

                  /* Note: setting SXFER only works if we're
                   * still in the MESSAGE phase, so it is vital
                   * that ACK is still asserted when we process
                   * the reselection message.  The resume offset
                   * should therefore always clear ACK */
                  NCR_700_writeb(NCR_700_get_SXFER(hostdata->cmd->device),
                               host, SXFER_REG);
                  dma_cache_sync(hostdata->dev, hostdata->msgin,
                               MSG_ARRAY_SIZE, DMA_FROM_DEVICE);
                  dma_cache_sync(hostdata->dev, hostdata->msgout,
                               MSG_ARRAY_SIZE, DMA_TO_DEVICE);
                  /* I'm just being paranoid here, the command should
                   * already have been flushed from the cache */
                  dma_cache_sync(hostdata->dev, slot->cmnd->cmnd,
                               slot->cmnd->cmd_len, DMA_TO_DEVICE);


                  
            }
      } else if(dsps == A_RESELECTED_DURING_SELECTION) {

            /* This section is full of debugging code because I've
             * never managed to reach it.  I think what happens is
             * that, because the 700 runs with selection
             * interrupts enabled the whole time that we take a
             * selection interrupt before we manage to get to the
             * reselected script interrupt */

            __u8 reselection_id = NCR_700_readb(host, SFBR_REG);
            struct NCR_700_command_slot *slot;
            
            /* Take out our own ID */
            reselection_id &= ~(1<<host->this_id);
            
            /* I've never seen this happen, so keep this as a printk rather
             * than a debug */
            printk(KERN_INFO "scsi%d: (%d:%d) RESELECTION DURING SELECTION, dsp=%08x[%04x] state=%d, count=%d\n",
                   host->host_no, reselection_id, lun, dsp, dsp - hostdata->pScript, hostdata->state, hostdata->command_slot_count);

            {
                  /* FIXME: DEBUGGING CODE */
                  __u32 SG = (__u32)bS_to_cpu(hostdata->script[A_SGScriptStartAddress_used[0]]);
                  int i;

                  for(i=0; i< NCR_700_COMMAND_SLOTS_PER_HOST; i++) {
                        if(SG >= to32bit(&hostdata->slots[i].pSG[0])
                           && SG <= to32bit(&hostdata->slots[i].pSG[NCR_700_SG_SEGMENTS]))
                              break;
                  }
                  printk(KERN_INFO "IDENTIFIED SG segment as being %08x in slot %p, cmd %p, slot->resume_offset=%08x\n", SG, &hostdata->slots[i], hostdata->slots[i].cmnd, hostdata->slots[i].resume_offset);
                  SCp =  hostdata->slots[i].cmnd;
            }

            if(SCp != NULL) {
                  slot = (struct NCR_700_command_slot *)SCp->host_scribble;
                  /* change slot from busy to queued to redo command */
                  slot->state = NCR_700_SLOT_QUEUED;
            }
            hostdata->cmd = NULL;
            
            if(reselection_id == 0) {
                  if(hostdata->reselection_id == 0xff) {
                        printk(KERN_ERR "scsi%d: Invalid reselection during selection!!\n", host->host_no);
                        return 0;
                  } else {
                        printk(KERN_ERR "scsi%d: script reselected and we took a selection interrupt\n",
                               host->host_no);
                        reselection_id = hostdata->reselection_id;
                  }
            } else {
                  
                  /* convert to real ID */
                  reselection_id = bitmap_to_number(reselection_id);
            }
            hostdata->reselection_id = reselection_id;
            /* just in case we have a stale simple tag message, clear it */
            hostdata->msgin[1] = 0;
            dma_cache_sync(hostdata->dev, hostdata->msgin,
                         MSG_ARRAY_SIZE, DMA_BIDIRECTIONAL);
            if(hostdata->tag_negotiated & (1<<reselection_id)) {
                  resume_offset = hostdata->pScript + Ent_GetReselectionWithTag;
            } else {
                  resume_offset = hostdata->pScript + Ent_GetReselectionData;
            }
      } else if(dsps == A_COMPLETED_SELECTION_AS_TARGET) {
            /* we've just disconnected from the bus, do nothing since
             * a return here will re-run the queued command slot
             * that may have been interrupted by the initial selection */
            DEBUG((" SELECTION COMPLETED\n"));
      } else if((dsps & 0xfffff0f0) == A_MSG_IN) { 
            resume_offset = process_message(host, hostdata, SCp,
                                    dsp, dsps);
      } else if((dsps &  0xfffff000) == 0) {
            __u8 i = (dsps & 0xf0) >> 4, j = (dsps & 0xf00) >> 8;
            printk(KERN_ERR "scsi%d: (%d:%d), unhandled script condition %s %s at %04x\n",
                   host->host_no, pun, lun, NCR_700_condition[i],
                   NCR_700_phase[j], dsp - hostdata->pScript);
            if(SCp != NULL) {
                  struct scatterlist *sg;

                  scsi_print_command(SCp);
                  scsi_for_each_sg(SCp, sg, scsi_sg_count(SCp) + 1, i) {
                        printk(KERN_INFO " SG[%d].length = %d, move_insn=%08x, addr %08x\n", i, sg->length, ((struct NCR_700_command_slot *)SCp->host_scribble)->SG[i].ins, ((struct NCR_700_command_slot *)SCp->host_scribble)->SG[i].pAddr);
                  }
            }
            NCR_700_internal_bus_reset(host);
      } else if((dsps & 0xfffff000) == A_DEBUG_INTERRUPT) {
            printk(KERN_NOTICE "scsi%d (%d:%d) DEBUG INTERRUPT %d AT %08x[%04x], continuing\n",
                   host->host_no, pun, lun, dsps & 0xfff, dsp, dsp - hostdata->pScript);
            resume_offset = dsp;
      } else {
            printk(KERN_ERR "scsi%d: (%d:%d), unidentified script interrupt 0x%x at %04x\n",
                   host->host_no, pun, lun, dsps, dsp - hostdata->pScript);
            NCR_700_internal_bus_reset(host);
      }
      return resume_offset;
}

/* We run the 53c700 with selection interrupts always enabled.  This
 * means that the chip may be selected as soon as the bus frees.  On a
 * busy bus, this can be before the scripts engine finishes its
 * processing.  Therefore, part of the selection processing has to be
 * to find out what the scripts engine is doing and complete the
 * function if necessary (i.e. process the pending disconnect or save
 * the interrupted initial selection */
STATIC inline __u32
process_selection(struct Scsi_Host *host, __u32 dsp)
{
      __u8 id = 0;      /* Squash compiler warning */
      int count = 0;
      __u32 resume_offset = 0;
      struct NCR_700_Host_Parameters *hostdata =
            (struct NCR_700_Host_Parameters *)host->hostdata[0];
      struct scsi_cmnd *SCp = hostdata->cmd;
      __u8 sbcl;

      for(count = 0; count < 5; count++) {
            id = NCR_700_readb(host, hostdata->chip710 ?
                           CTEST9_REG : SFBR_REG);

            /* Take out our own ID */
            id &= ~(1<<host->this_id);
            if(id != 0) 
                  break;
            udelay(5);
      }
      sbcl = NCR_700_readb(host, SBCL_REG);
      if((sbcl & SBCL_IO) == 0) {
            /* mark as having been selected rather than reselected */
            id = 0xff;
      } else {
            /* convert to real ID */
            hostdata->reselection_id = id = bitmap_to_number(id);
            DEBUG(("scsi%d:  Reselected by %d\n",
                   host->host_no, id));
      }
      if(hostdata->state == NCR_700_HOST_BUSY && SCp != NULL) {
            struct NCR_700_command_slot *slot =
                  (struct NCR_700_command_slot *)SCp->host_scribble;
            DEBUG(("  ID %d WARNING: RESELECTION OF BUSY HOST, saving cmd %p, slot %p, addr %x [%04x], resume %x!\n", id, hostdata->cmd, slot, dsp, dsp - hostdata->pScript, resume_offset));
            
            switch(dsp - hostdata->pScript) {
            case Ent_Disconnect1:
            case Ent_Disconnect2:
                  save_for_reselection(hostdata, SCp, Ent_Disconnect2 + hostdata->pScript);
                  break;
            case Ent_Disconnect3:
            case Ent_Disconnect4:
                  save_for_reselection(hostdata, SCp, Ent_Disconnect4 + hostdata->pScript);
                  break;
            case Ent_Disconnect5:
            case Ent_Disconnect6:
                  save_for_reselection(hostdata, SCp, Ent_Disconnect6 + hostdata->pScript);
                  break;
            case Ent_Disconnect7:
            case Ent_Disconnect8:
                  save_for_reselection(hostdata, SCp, Ent_Disconnect8 + hostdata->pScript);
                  break;
            case Ent_Finish1:
            case Ent_Finish2:
                  process_script_interrupt(A_GOOD_STATUS_AFTER_STATUS, dsp, SCp, host, hostdata);
                  break;
                  
            default:
                  slot->state = NCR_700_SLOT_QUEUED;
                  break;
                  }
      }
      hostdata->state = NCR_700_HOST_BUSY;
      hostdata->cmd = NULL;
      /* clear any stale simple tag message */
      hostdata->msgin[1] = 0;
      dma_cache_sync(hostdata->dev, hostdata->msgin, MSG_ARRAY_SIZE,
                   DMA_BIDIRECTIONAL);

      if(id == 0xff) {
            /* Selected as target, Ignore */
            resume_offset = hostdata->pScript + Ent_SelectedAsTarget;
      } else if(hostdata->tag_negotiated & (1<<id)) {
            resume_offset = hostdata->pScript + Ent_GetReselectionWithTag;
      } else {
            resume_offset = hostdata->pScript + Ent_GetReselectionData;
      }
      return resume_offset;
}

static inline void
NCR_700_clear_fifo(struct Scsi_Host *host) {
      const struct NCR_700_Host_Parameters *hostdata
            = (struct NCR_700_Host_Parameters *)host->hostdata[0];
      if(hostdata->chip710) {
            NCR_700_writeb(CLR_FIFO_710, host, CTEST8_REG);
      } else {
            NCR_700_writeb(CLR_FIFO, host, DFIFO_REG);
      }
}

static inline void
NCR_700_flush_fifo(struct Scsi_Host *host) {
      const struct NCR_700_Host_Parameters *hostdata
            = (struct NCR_700_Host_Parameters *)host->hostdata[0];
      if(hostdata->chip710) {
            NCR_700_writeb(FLUSH_DMA_FIFO_710, host, CTEST8_REG);
            udelay(10);
            NCR_700_writeb(0, host, CTEST8_REG);
      } else {
            NCR_700_writeb(FLUSH_DMA_FIFO, host, DFIFO_REG);
            udelay(10);
            NCR_700_writeb(0, host, DFIFO_REG);
      }
}


/* The queue lock with interrupts disabled must be held on entry to
 * this function */
STATIC int
NCR_700_start_command(struct scsi_cmnd *SCp)
{
      struct NCR_700_command_slot *slot =
            (struct NCR_700_command_slot *)SCp->host_scribble;
      struct NCR_700_Host_Parameters *hostdata =
            (struct NCR_700_Host_Parameters *)SCp->device->host->hostdata[0];
      __u16 count = 1;  /* for IDENTIFY message */
      
      if(hostdata->state != NCR_700_HOST_FREE) {
            /* keep this inside the lock to close the race window where
             * the running command finishes on another CPU while we don't
             * change the state to queued on this one */
            slot->state = NCR_700_SLOT_QUEUED;

            DEBUG(("scsi%d: host busy, queueing command %p, slot %p\n",
                   SCp->device->host->host_no, slot->cmnd, slot));
            return 0;
      }
      hostdata->state = NCR_700_HOST_BUSY;
      hostdata->cmd = SCp;
      slot->state = NCR_700_SLOT_BUSY;
      /* keep interrupts disabled until we have the command correctly
       * set up so we cannot take a selection interrupt */

      hostdata->msgout[0] = NCR_700_identify((SCp->cmnd[0] != REQUEST_SENSE &&
                                    slot->flags != NCR_700_FLAG_AUTOSENSE),
                                     SCp->device->lun);
      /* for INQUIRY or REQUEST_SENSE commands, we cannot be sure
       * if the negotiated transfer parameters still hold, so
       * always renegotiate them */
      if(SCp->cmnd[0] == INQUIRY || SCp->cmnd[0] == REQUEST_SENSE ||
         slot->flags == NCR_700_FLAG_AUTOSENSE) {
            NCR_700_clear_flag(SCp->device, NCR_700_DEV_NEGOTIATED_SYNC);
      }

      /* REQUEST_SENSE is asking for contingent I_T_L(_Q) status.
       * If a contingent allegiance condition exists, the device
       * will refuse all tags, so send the request sense as untagged
       * */
      if((hostdata->tag_negotiated & (1<<scmd_id(SCp)))
         && (slot->tag != SCSI_NO_TAG && SCp->cmnd[0] != REQUEST_SENSE &&
             slot->flags != NCR_700_FLAG_AUTOSENSE)) {
            count += scsi_populate_tag_msg(SCp, &hostdata->msgout[count]);
      }

      if(hostdata->fast &&
         NCR_700_is_flag_clear(SCp->device, NCR_700_DEV_NEGOTIATED_SYNC)) {
            count += spi_populate_sync_msg(&hostdata->msgout[count],
                        spi_period(SCp->device->sdev_target),
                        spi_offset(SCp->device->sdev_target));
            NCR_700_set_flag(SCp->device, NCR_700_DEV_BEGIN_SYNC_NEGOTIATION);
      }

      script_patch_16(hostdata->dev, hostdata->script, MessageCount, count);


      script_patch_ID(hostdata->dev, hostdata->script,
                  Device_ID, 1<<scmd_id(SCp));

      script_patch_32_abs(hostdata->dev, hostdata->script, CommandAddress,
                      slot->pCmd);
      script_patch_16(hostdata->dev, hostdata->script, CommandCount,
                      SCp->cmd_len);
      /* finally plumb the beginning of the SG list into the script
       * */
      script_patch_32_abs(hostdata->dev, hostdata->script,
                          SGScriptStartAddress, to32bit(&slot->pSG[0].ins));
      NCR_700_clear_fifo(SCp->device->host);

      if(slot->resume_offset == 0)
            slot->resume_offset = hostdata->pScript;
      /* now perform all the writebacks and invalidates */
      dma_cache_sync(hostdata->dev, hostdata->msgout, count, DMA_TO_DEVICE);
      dma_cache_sync(hostdata->dev, hostdata->msgin, MSG_ARRAY_SIZE,
                   DMA_FROM_DEVICE);
      dma_cache_sync(hostdata->dev, SCp->cmnd, SCp->cmd_len, DMA_TO_DEVICE);
      dma_cache_sync(hostdata->dev, hostdata->status, 1, DMA_FROM_DEVICE);

      /* set the synchronous period/offset */
      NCR_700_writeb(NCR_700_get_SXFER(SCp->device),
                   SCp->device->host, SXFER_REG);
      NCR_700_writel(slot->temp, SCp->device->host, TEMP_REG);
      NCR_700_writel(slot->resume_offset, SCp->device->host, DSP_REG);

      return 1;
}

irqreturn_t
NCR_700_intr(int irq, void *dev_id)
{
      struct Scsi_Host *host = (struct Scsi_Host *)dev_id;
      struct NCR_700_Host_Parameters *hostdata =
            (struct NCR_700_Host_Parameters *)host->hostdata[0];
      __u8 istat;
      __u32 resume_offset = 0;
      __u8 pun = 0xff, lun = 0xff;
      unsigned long flags;
      int handled = 0;

      /* Use the host lock to serialise acess to the 53c700
       * hardware.  Note: In future, we may need to take the queue
       * lock to enter the done routines.  When that happens, we
       * need to ensure that for this driver, the host lock and the
       * queue lock point to the same thing. */
      spin_lock_irqsave(host->host_lock, flags);
      if((istat = NCR_700_readb(host, ISTAT_REG))
            & (SCSI_INT_PENDING | DMA_INT_PENDING)) {
            __u32 dsps;
            __u8 sstat0 = 0, dstat = 0;
            __u32 dsp;
            struct scsi_cmnd *SCp = hostdata->cmd;
            enum NCR_700_Host_State state;

            handled = 1;
            state = hostdata->state;
            SCp = hostdata->cmd;

            if(istat & SCSI_INT_PENDING) {
                  udelay(10);

                  sstat0 = NCR_700_readb(host, SSTAT0_REG);
            }

            if(istat & DMA_INT_PENDING) {
                  udelay(10);

                  dstat = NCR_700_readb(host, DSTAT_REG);
            }

            dsps = NCR_700_readl(host, DSPS_REG);
            dsp = NCR_700_readl(host, DSP_REG);

            DEBUG(("scsi%d: istat %02x sstat0 %02x dstat %02x dsp %04x[%08x] dsps 0x%x\n",
                   host->host_no, istat, sstat0, dstat,
                   (dsp - (__u32)(hostdata->pScript))/4,
                   dsp, dsps));

            if(SCp != NULL) {
                  pun = SCp->device->id;
                  lun = SCp->device->lun;
            }

            if(sstat0 & SCSI_RESET_DETECTED) {
                  struct scsi_device *SDp;
                  int i;

                  hostdata->state = NCR_700_HOST_BUSY;

                  printk(KERN_ERR "scsi%d: Bus Reset detected, executing command %p, slot %p, dsp %08x[%04x]\n",
                         host->host_no, SCp, SCp == NULL ? NULL : SCp->host_scribble, dsp, dsp - hostdata->pScript);

                  scsi_report_bus_reset(host, 0);

                  /* clear all the negotiated parameters */
                  __shost_for_each_device(SDp, host)
                        NCR_700_clear_flag(SDp, ~0);
                  
                  /* clear all the slots and their pending commands */
                  for(i = 0; i < NCR_700_COMMAND_SLOTS_PER_HOST; i++) {
                        struct scsi_cmnd *SCp;
                        struct NCR_700_command_slot *slot =
                              &hostdata->slots[i];

                        if(slot->state == NCR_700_SLOT_FREE)
                              continue;
                        
                        SCp = slot->cmnd;
                        printk(KERN_ERR " failing command because of reset, slot %p, cmnd %p\n",
                               slot, SCp);
                        free_slot(slot, hostdata);
                        SCp->host_scribble = NULL;
                        NCR_700_set_depth(SCp->device, 0);
                        /* NOTE: deadlock potential here: we
                         * rely on mid-layer guarantees that
                         * scsi_done won't try to issue the
                         * command again otherwise we'll
                         * deadlock on the
                         * hostdata->state_lock */
                        SCp->result = DID_RESET << 16;
                        SCp->scsi_done(SCp);
                  }
                  mdelay(25);
                  NCR_700_chip_setup(host);

                  hostdata->state = NCR_700_HOST_FREE;
                  hostdata->cmd = NULL;
                  /* signal back if this was an eh induced reset */
                  if(hostdata->eh_complete != NULL)
                        complete(hostdata->eh_complete);
                  goto out_unlock;
            } else if(sstat0 & SELECTION_TIMEOUT) {
                  DEBUG(("scsi%d: (%d:%d) selection timeout\n",
                         host->host_no, pun, lun));
                  NCR_700_scsi_done(hostdata, SCp, DID_NO_CONNECT<<16);
            } else if(sstat0 & PHASE_MISMATCH) {
                  struct NCR_700_command_slot *slot = (SCp == NULL) ? NULL :
                        (struct NCR_700_command_slot *)SCp->host_scribble;

                  if(dsp == Ent_SendMessage + 8 + hostdata->pScript) {
                        /* It wants to reply to some part of
                         * our message */
#ifdef NCR_700_DEBUG
                        __u32 temp = NCR_700_readl(host, TEMP_REG);
                        int count = (hostdata->script[Ent_SendMessage/4] & 0xffffff) - ((NCR_700_readl(host, DBC_REG) & 0xffffff) + NCR_700_data_residual(host));
                        printk("scsi%d (%d:%d) PHASE MISMATCH IN SEND MESSAGE %d remain, return %p[%04x], phase %s\n", host->host_no, pun, lun, count, (void *)temp, temp - hostdata->pScript, sbcl_to_string(NCR_700_readb(host, SBCL_REG)));
#endif
                        resume_offset = hostdata->pScript + Ent_SendMessagePhaseMismatch;
                  } else if(dsp >= to32bit(&slot->pSG[0].ins) &&
                          dsp <= to32bit(&slot->pSG[NCR_700_SG_SEGMENTS].ins)) {
                        int data_transfer = NCR_700_readl(host, DBC_REG) & 0xffffff;
                        int SGcount = (dsp - to32bit(&slot->pSG[0].ins))/sizeof(struct NCR_700_SG_List);
                        int residual = NCR_700_data_residual(host);
                        int i;
#ifdef NCR_700_DEBUG
                        __u32 naddr = NCR_700_readl(host, DNAD_REG);

                        printk("scsi%d: (%d:%d) Expected phase mismatch in slot->SG[%d], transferred 0x%x\n",
                               host->host_no, pun, lun,
                               SGcount, data_transfer);
                        scsi_print_command(SCp);
                        if(residual) {
                              printk("scsi%d: (%d:%d) Expected phase mismatch in slot->SG[%d], transferred 0x%x, residual %d\n",
                               host->host_no, pun, lun,
                               SGcount, data_transfer, residual);
                        }
#endif
                        data_transfer += residual;

                        if(data_transfer != 0) {
                              int count; 
                              __u32 pAddr;

                              SGcount--;

                              count = (bS_to_cpu(slot->SG[SGcount].ins) & 0x00ffffff);
                              DEBUG(("DATA TRANSFER MISMATCH, count = %d, transferred %d\n", count, count-data_transfer));
                              slot->SG[SGcount].ins &= bS_to_host(0xff000000);
                              slot->SG[SGcount].ins |= bS_to_host(data_transfer);
                              pAddr = bS_to_cpu(slot->SG[SGcount].pAddr);
                              pAddr += (count - data_transfer);
#ifdef NCR_700_DEBUG
                              if(pAddr != naddr) {
                                    printk("scsi%d (%d:%d) transfer mismatch pAddr=%lx, naddr=%lx, data_transfer=%d, residual=%d\n", host->host_no, pun, lun, (unsigned long)pAddr, (unsigned long)naddr, data_transfer, residual);
                              }
#endif
                              slot->SG[SGcount].pAddr = bS_to_host(pAddr);
                        }
                        /* set the executed moves to nops */
                        for(i=0; i<SGcount; i++) {
                              slot->SG[i].ins = bS_to_host(SCRIPT_NOP);
                              slot->SG[i].pAddr = 0;
                        }
                        dma_cache_sync(hostdata->dev, slot->SG, sizeof(slot->SG), DMA_TO_DEVICE);
                        /* and pretend we disconnected after
                         * the command phase */
                        resume_offset = hostdata->pScript + Ent_MsgInDuringData;
                        /* make sure all the data is flushed */
                        NCR_700_flush_fifo(host);
                  } else {
                        __u8 sbcl = NCR_700_readb(host, SBCL_REG);
                        printk(KERN_ERR "scsi%d: (%d:%d) phase mismatch at %04x, phase %s\n",
                               host->host_no, pun, lun, dsp - hostdata->pScript, sbcl_to_string(sbcl));
                        NCR_700_internal_bus_reset(host);
                  }

            } else if(sstat0 & SCSI_GROSS_ERROR) {
                  printk(KERN_ERR "scsi%d: (%d:%d) GROSS ERROR\n",
                         host->host_no, pun, lun);
                  NCR_700_scsi_done(hostdata, SCp, DID_ERROR<<16);
            } else if(sstat0 & PARITY_ERROR) {
                  printk(KERN_ERR "scsi%d: (%d:%d) PARITY ERROR\n",
                         host->host_no, pun, lun);
                  NCR_700_scsi_done(hostdata, SCp, DID_ERROR<<16);
            } else if(dstat & SCRIPT_INT_RECEIVED) {
                  DEBUG(("scsi%d: (%d:%d) ====>SCRIPT INTERRUPT<====\n",
                         host->host_no, pun, lun));
                  resume_offset = process_script_interrupt(dsps, dsp, SCp, host, hostdata);
            } else if(dstat & (ILGL_INST_DETECTED)) {
                  printk(KERN_ERR "scsi%d: (%d:%d) Illegal Instruction detected at 0x%08x[0x%x]!!!\n"
                         "         Please email James.Bottomley@HansenPartnership.com with the details\n",
                         host->host_no, pun, lun,
                         dsp, dsp - hostdata->pScript);
                  NCR_700_scsi_done(hostdata, SCp, DID_ERROR<<16);
            } else if(dstat & (WATCH_DOG_INTERRUPT|ABORTED)) {
                  printk(KERN_ERR "scsi%d: (%d:%d) serious DMA problem, dstat=%02x\n",
                         host->host_no, pun, lun, dstat);
                  NCR_700_scsi_done(hostdata, SCp, DID_ERROR<<16);
            }

            
            /* NOTE: selection interrupt processing MUST occur
             * after script interrupt processing to correctly cope
             * with the case where we process a disconnect and
             * then get reselected before we process the
             * disconnection */
            if(sstat0 & SELECTED) {
                  /* FIXME: It currently takes at least FOUR
                   * interrupts to complete a command that
                   * disconnects: one for the disconnect, one
                   * for the reselection, one to get the
                   * reselection data and one to complete the
                   * command.  If we guess the reselected
                   * command here and prepare it, we only need
                   * to get a reselection data interrupt if we
                   * guessed wrongly.  Since the interrupt
                   * overhead is much greater than the command
                   * setup, this would be an efficient
                   * optimisation particularly as we probably
                   * only have one outstanding command on a
                   * target most of the time */

                  resume_offset = process_selection(host, dsp);

            }

      }

      if(resume_offset) {
            if(hostdata->state != NCR_700_HOST_BUSY) {
                  printk(KERN_ERR "scsi%d: Driver error: resume at 0x%08x [0x%04x] with non busy host!\n",
                         host->host_no, resume_offset, resume_offset - hostdata->pScript);
                  hostdata->state = NCR_700_HOST_BUSY;
            }

            DEBUG(("Attempting to resume at %x\n", resume_offset));
            NCR_700_clear_fifo(host);
            NCR_700_writel(resume_offset, host, DSP_REG);
      } 
      /* There is probably a technical no-no about this: If we're a
       * shared interrupt and we got this interrupt because the
       * other device needs servicing not us, we're still going to
       * check our queued commands here---of course, there shouldn't
       * be any outstanding.... */
      if(hostdata->state == NCR_700_HOST_FREE) {
            int i;

            for(i = 0; i < NCR_700_COMMAND_SLOTS_PER_HOST; i++) {
                  /* fairness: always run the queue from the last
                   * position we left off */
                  int j = (i + hostdata->saved_slot_position)
                        % NCR_700_COMMAND_SLOTS_PER_HOST;
                  
                  if(hostdata->slots[j].state != NCR_700_SLOT_QUEUED)
                        continue;
                  if(NCR_700_start_command(hostdata->slots[j].cmnd)) {
                        DEBUG(("scsi%d: Issuing saved command slot %p, cmd %p\t\n",
                               host->host_no, &hostdata->slots[j],
                               hostdata->slots[j].cmnd));
                        hostdata->saved_slot_position = j + 1;
                  }

                  break;
            }
      }
 out_unlock:
      spin_unlock_irqrestore(host->host_lock, flags);
      return IRQ_RETVAL(handled);
}

STATIC int
NCR_700_queuecommand(struct scsi_cmnd *SCp, void (*done)(struct scsi_cmnd *))
{
      struct NCR_700_Host_Parameters *hostdata = 
            (struct NCR_700_Host_Parameters *)SCp->device->host->hostdata[0];
      __u32 move_ins;
      enum dma_data_direction direction;
      struct NCR_700_command_slot *slot;

      if(hostdata->command_slot_count >= NCR_700_COMMAND_SLOTS_PER_HOST) {
            /* We're over our allocation, this should never happen
             * since we report the max allocation to the mid layer */
            printk(KERN_WARNING "scsi%d: Command depth has gone over queue depth\n", SCp->device->host->host_no);
            return 1;
      }
      /* check for untagged commands.  We cannot have any outstanding
       * commands if we accept them.  Commands could be untagged because:
       *
       * - The tag negotiated bitmap is clear
       * - The blk layer sent and untagged command
       */
      if(NCR_700_get_depth(SCp->device) != 0
         && (!(hostdata->tag_negotiated & (1<<scmd_id(SCp)))
             || !blk_rq_tagged(SCp->request))) {
            CDEBUG(KERN_ERR, SCp, "has non zero depth %d\n",
                   NCR_700_get_depth(SCp->device));
            return SCSI_MLQUEUE_DEVICE_BUSY;
      }
      if(NCR_700_get_depth(SCp->device) >= SCp->device->queue_depth) {
            CDEBUG(KERN_ERR, SCp, "has max tag depth %d\n",
                   NCR_700_get_depth(SCp->device));
            return SCSI_MLQUEUE_DEVICE_BUSY;
      }
      NCR_700_set_depth(SCp->device, NCR_700_get_depth(SCp->device) + 1);

      /* begin the command here */
      /* no need to check for NULL, test for command_slot_count above
       * ensures a slot is free */
      slot = find_empty_slot(hostdata);

      slot->cmnd = SCp;

      SCp->scsi_done = done;
      SCp->host_scribble = (unsigned char *)slot;
      SCp->SCp.ptr = NULL;
      SCp->SCp.buffer = NULL;

#ifdef NCR_700_DEBUG
      printk("53c700: scsi%d, command ", SCp->device->host->host_no);
      scsi_print_command(SCp);
#endif
      if(blk_rq_tagged(SCp->request)
         && (hostdata->tag_negotiated &(1<<scmd_id(SCp))) == 0
         && NCR_700_get_tag_neg_state(SCp->device) == NCR_700_START_TAG_NEGOTIATION) {
            scmd_printk(KERN_ERR, SCp, "Enabling Tag Command Queuing\n");
            hostdata->tag_negotiated |= (1<<scmd_id(SCp));
            NCR_700_set_tag_neg_state(SCp->device, NCR_700_DURING_TAG_NEGOTIATION);
      }

      /* here we may have to process an untagged command.  The gate
       * above ensures that this will be the only one outstanding,
       * so clear the tag negotiated bit.
       *
       * FIXME: This will royally screw up on multiple LUN devices
       * */
      if(!blk_rq_tagged(SCp->request)
         && (hostdata->tag_negotiated &(1<<scmd_id(SCp)))) {
            scmd_printk(KERN_INFO, SCp, "Disabling Tag Command Queuing\n");
            hostdata->tag_negotiated &= ~(1<<scmd_id(SCp));
      }

      if((hostdata->tag_negotiated &(1<<scmd_id(SCp)))
         && scsi_get_tag_type(SCp->device)) {
            slot->tag = SCp->request->tag;
            CDEBUG(KERN_DEBUG, SCp, "sending out tag %d, slot %p\n",
                   slot->tag, slot);
      } else {
            slot->tag = SCSI_NO_TAG;
            /* must populate current_cmnd for scsi_find_tag to work */
            SCp->device->current_cmnd = SCp;
      }
      /* sanity check: some of the commands generated by the mid-layer
       * have an eccentric idea of their sc_data_direction */
      if(!scsi_sg_count(SCp) && !scsi_bufflen(SCp) &&
         SCp->sc_data_direction != DMA_NONE) {
#ifdef NCR_700_DEBUG
            printk("53c700: Command");
            scsi_print_command(SCp);
            printk("Has wrong data direction %d\n", SCp->sc_data_direction);
#endif
            SCp->sc_data_direction = DMA_NONE;
      }

      switch (SCp->cmnd[0]) {
      case REQUEST_SENSE:
            /* clear the internal sense magic */
            SCp->cmnd[6] = 0;
            /* fall through */
      default:
            /* OK, get it from the command */
            switch(SCp->sc_data_direction) {
            case DMA_BIDIRECTIONAL:
            default:
                  printk(KERN_ERR "53c700: Unknown command for data direction ");
                  scsi_print_command(SCp);
                  
                  move_ins = 0;
                  break;
            case DMA_NONE:
                  move_ins = 0;
                  break;
            case DMA_FROM_DEVICE:
                  move_ins = SCRIPT_MOVE_DATA_IN;
                  break;
            case DMA_TO_DEVICE:
                  move_ins = SCRIPT_MOVE_DATA_OUT;
                  break;
            }
      }

      /* now build the scatter gather list */
      direction = SCp->sc_data_direction;
      if(move_ins != 0) {
            int i;
            int sg_count;
            dma_addr_t vPtr = 0;
            struct scatterlist *sg;
            __u32 count = 0;

            sg_count = scsi_dma_map(SCp);
            BUG_ON(sg_count < 0);

            scsi_for_each_sg(SCp, sg, sg_count, i) {
                  vPtr = sg_dma_address(sg);
                  count = sg_dma_len(sg);

                  slot->SG[i].ins = bS_to_host(move_ins | count);
                  DEBUG((" scatter block %d: move %d[%08x] from 0x%lx\n",
                         i, count, slot->SG[i].ins, (unsigned long)vPtr));
                  slot->SG[i].pAddr = bS_to_host(vPtr);
            }
            slot->SG[i].ins = bS_to_host(SCRIPT_RETURN);
            slot->SG[i].pAddr = 0;
            dma_cache_sync(hostdata->dev, slot->SG, sizeof(slot->SG), DMA_TO_DEVICE);
            DEBUG((" SETTING %08lx to %x\n",
                   (&slot->pSG[i].ins),
                   slot->SG[i].ins));
      }
      slot->resume_offset = 0;
      slot->pCmd = dma_map_single(hostdata->dev, SCp->cmnd,
                            sizeof(SCp->cmnd), DMA_TO_DEVICE);
      NCR_700_start_command(SCp);
      return 0;
}

STATIC int
NCR_700_abort(struct scsi_cmnd * SCp)
{
      struct NCR_700_command_slot *slot;

      scmd_printk(KERN_INFO, SCp,
            "New error handler wants to abort command\n\t");
      scsi_print_command(SCp);

      slot = (struct NCR_700_command_slot *)SCp->host_scribble;

      if(slot == NULL)
            /* no outstanding command to abort */
            return SUCCESS;
      if(SCp->cmnd[0] == TEST_UNIT_READY) {
            /* FIXME: This is because of a problem in the new
             * error handler.  When it is in error recovery, it
             * will send a TUR to a device it thinks may still be
             * showing a problem.  If the TUR isn't responded to,
             * it will abort it and mark the device off line.
             * Unfortunately, it does no other error recovery, so
             * this would leave us with an outstanding command
             * occupying a slot.  Rather than allow this to
             * happen, we issue a bus reset to force all
             * outstanding commands to terminate here. */
            NCR_700_internal_bus_reset(SCp->device->host);
            /* still drop through and return failed */
      }
      return FAILED;

}

STATIC int
NCR_700_bus_reset(struct scsi_cmnd * SCp)
{
      DECLARE_COMPLETION_ONSTACK(complete);
      struct NCR_700_Host_Parameters *hostdata = 
            (struct NCR_700_Host_Parameters *)SCp->device->host->hostdata[0];

      scmd_printk(KERN_INFO, SCp,
            "New error handler wants BUS reset, cmd %p\n\t", SCp);
      scsi_print_command(SCp);

      /* In theory, eh_complete should always be null because the
       * eh is single threaded, but just in case we're handling a
       * reset via sg or something */
      spin_lock_irq(SCp->device->host->host_lock);
      while (hostdata->eh_complete != NULL) {
            spin_unlock_irq(SCp->device->host->host_lock);
            msleep_interruptible(100);
            spin_lock_irq(SCp->device->host->host_lock);
      }

      hostdata->eh_complete = &complete;
      NCR_700_internal_bus_reset(SCp->device->host);

      spin_unlock_irq(SCp->device->host->host_lock);
      wait_for_completion(&complete);
      spin_lock_irq(SCp->device->host->host_lock);

      hostdata->eh_complete = NULL;
      /* Revalidate the transport parameters of the failing device */
      if(hostdata->fast)
            spi_schedule_dv_device(SCp->device);

      spin_unlock_irq(SCp->device->host->host_lock);
      return SUCCESS;
}

STATIC int
NCR_700_host_reset(struct scsi_cmnd * SCp)
{
      scmd_printk(KERN_INFO, SCp, "New error handler wants HOST reset\n\t");
      scsi_print_command(SCp);

      spin_lock_irq(SCp->device->host->host_lock);

      NCR_700_internal_bus_reset(SCp->device->host);
      NCR_700_chip_reset(SCp->device->host);

      spin_unlock_irq(SCp->device->host->host_lock);

      return SUCCESS;
}

STATIC void
NCR_700_set_period(struct scsi_target *STp, int period)
{
      struct Scsi_Host *SHp = dev_to_shost(STp->dev.parent);
      struct NCR_700_Host_Parameters *hostdata = 
            (struct NCR_700_Host_Parameters *)SHp->hostdata[0];
      
      if(!hostdata->fast)
            return;

      if(period < hostdata->min_period)
            period = hostdata->min_period;

      spi_period(STp) = period;
      spi_flags(STp) &= ~(NCR_700_DEV_NEGOTIATED_SYNC |
                      NCR_700_DEV_BEGIN_SYNC_NEGOTIATION);
      spi_flags(STp) |= NCR_700_DEV_PRINT_SYNC_NEGOTIATION;
}

STATIC void
NCR_700_set_offset(struct scsi_target *STp, int offset)
{
      struct Scsi_Host *SHp = dev_to_shost(STp->dev.parent);
      struct NCR_700_Host_Parameters *hostdata = 
            (struct NCR_700_Host_Parameters *)SHp->hostdata[0];
      int max_offset = hostdata->chip710
            ? NCR_710_MAX_OFFSET : NCR_700_MAX_OFFSET;
      
      if(!hostdata->fast)
            return;

      if(offset > max_offset)
            offset = max_offset;

      /* if we're currently async, make sure the period is reasonable */
      if(spi_offset(STp) == 0 && (spi_period(STp) < hostdata->min_period ||
                            spi_period(STp) > 0xff))
            spi_period(STp) = hostdata->min_period;

      spi_offset(STp) = offset;
      spi_flags(STp) &= ~(NCR_700_DEV_NEGOTIATED_SYNC |
                      NCR_700_DEV_BEGIN_SYNC_NEGOTIATION);
      spi_flags(STp) |= NCR_700_DEV_PRINT_SYNC_NEGOTIATION;
}

STATIC int
NCR_700_slave_alloc(struct scsi_device *SDp)
{
      SDp->hostdata = kzalloc(sizeof(struct NCR_700_Device_Parameters),
                        GFP_KERNEL);

      if (!SDp->hostdata)
            return -ENOMEM;

      return 0;
}

STATIC int
NCR_700_slave_configure(struct scsi_device *SDp)
{
      struct NCR_700_Host_Parameters *hostdata = 
            (struct NCR_700_Host_Parameters *)SDp->host->hostdata[0];

      /* to do here: allocate memory; build a queue_full list */
      if(SDp->tagged_supported) {
            scsi_set_tag_type(SDp, MSG_ORDERED_TAG);
            scsi_activate_tcq(SDp, NCR_700_DEFAULT_TAGS);
            NCR_700_set_tag_neg_state(SDp, NCR_700_START_TAG_NEGOTIATION);
      } else {
            /* initialise to default depth */
            scsi_adjust_queue_depth(SDp, 0, SDp->host->cmd_per_lun);
      }
      if(hostdata->fast) {
            /* Find the correct offset and period via domain validation */
            if (!spi_initial_dv(SDp->sdev_target))
                  spi_dv_device(SDp);
      } else {
            spi_offset(SDp->sdev_target) = 0;
            spi_period(SDp->sdev_target) = 0;
      }
      return 0;
}

STATIC void
NCR_700_slave_destroy(struct scsi_device *SDp)
{
      kfree(SDp->hostdata);
      SDp->hostdata = NULL;
}

static int
NCR_700_change_queue_depth(struct scsi_device *SDp, int depth)
{
      if (depth > NCR_700_MAX_TAGS)
            depth = NCR_700_MAX_TAGS;

      scsi_adjust_queue_depth(SDp, scsi_get_tag_type(SDp), depth);
      return depth;
}

static int NCR_700_change_queue_type(struct scsi_device *SDp, int tag_type)
{
      int change_tag = ((tag_type ==0 &&  scsi_get_tag_type(SDp) != 0)
                    || (tag_type != 0 && scsi_get_tag_type(SDp) == 0));
      struct NCR_700_Host_Parameters *hostdata = 
            (struct NCR_700_Host_Parameters *)SDp->host->hostdata[0];

      scsi_set_tag_type(SDp, tag_type);

      /* We have a global (per target) flag to track whether TCQ is
       * enabled, so we'll be turning it off for the entire target here.
       * our tag algorithm will fail if we mix tagged and untagged commands,
       * so quiesce the device before doing this */
      if (change_tag)
            scsi_target_quiesce(SDp->sdev_target);

      if (!tag_type) {
            /* shift back to the default unqueued number of commands
             * (the user can still raise this) */
            scsi_deactivate_tcq(SDp, SDp->host->cmd_per_lun);
            hostdata->tag_negotiated &= ~(1 << sdev_id(SDp));
      } else {
            /* Here, we cleared the negotiation flag above, so this
             * will force the driver to renegotiate */
            scsi_activate_tcq(SDp, SDp->queue_depth);
            if (change_tag)
                  NCR_700_set_tag_neg_state(SDp, NCR_700_START_TAG_NEGOTIATION);
      }
      if (change_tag)
            scsi_target_resume(SDp->sdev_target);

      return tag_type;
}

static ssize_t
NCR_700_show_active_tags(struct device *dev, struct device_attribute *attr, char *buf)
{
      struct scsi_device *SDp = to_scsi_device(dev);

      return snprintf(buf, 20, "%d\n", NCR_700_get_depth(SDp));
}

static struct device_attribute NCR_700_active_tags_attr = {
      .attr = {
            .name =           "active_tags",
            .mode =           S_IRUGO,
      },
      .show = NCR_700_show_active_tags,
};

STATIC struct device_attribute *NCR_700_dev_attrs[] = {
      &NCR_700_active_tags_attr,
      NULL,
};

EXPORT_SYMBOL(NCR_700_detect);
EXPORT_SYMBOL(NCR_700_release);
EXPORT_SYMBOL(NCR_700_intr);

static struct spi_function_template NCR_700_transport_functions =  {
      .set_period = NCR_700_set_period,
      .show_period      = 1,
      .set_offset = NCR_700_set_offset,
      .show_offset      = 1,
};

static int __init NCR_700_init(void)
{
      NCR_700_transport_template = spi_attach_transport(&NCR_700_transport_functions);
      if(!NCR_700_transport_template)
            return -ENODEV;
      return 0;
}

static void __exit NCR_700_exit(void)
{
      spi_release_transport(NCR_700_transport_template);
}

module_init(NCR_700_init);
module_exit(NCR_700_exit);


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