53c700.c

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

/* NCR (or Symbios) 53c700 and 53c700-66 Driver
 *
 * Copyright (C) 2001 by [email protected]
**-----------------------------------------------------------------------------
**  
**  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 <[email protected]> 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/slab.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/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_Host *h, 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, int reason);
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;
    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 [email protected]\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,
                 MAX_COMMAND_SIZE, 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,
                     SCSI_SENSE_BUFFERSIZE, 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,
                         MAX_COMMAND_SIZE,
                         DMA_TO_DEVICE);

                cmnd[0] = REQUEST_SENSE;
                cmnd[1] = (SCp->device->lun & 0x7) << 5;
                cmnd[2] = 0;
                cmnd[3] = 0;
                cmnd[4] = SCSI_SENSE_BUFFERSIZE;
                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, SCSI_SENSE_BUFFERSIZE, DMA_FROM_DEVICE);
                slot->SG[0].ins = bS_to_host(SCRIPT_MOVE_DATA_IN | SCSI_SENSE_BUFFERSIZE);
                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, SCSI_SENSE_BUFFERSIZE, 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 access 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 [email protected] 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_lck(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,
                    MAX_COMMAND_SIZE, DMA_TO_DEVICE);
    NCR_700_start_command(SCp);
    return 0;
}

STATIC DEF_SCSI_QCMD(NCR_700_queuecommand)

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, int reason)
{
    if (reason != SCSI_QDEPTH_DEFAULT)
        return -EOPNOTSUPP;

    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);