/*
 * 53c710 driver.  Modified from Drew Eckhardts driver
 * for 53c810 by Richard Hirst [richard@sleepie.demon.co.uk]
 * Check out PERM_OPTIONS and EXPECTED_CLOCK, which may be defined in the
 * relevant machine specific file (eg. mvme16x.[ch], amiga7xx.[ch]).
 * There are also currently some defines at the top of 53c7xx.scr.
 * The chip type is #defined in script_asm.pl, as well as the Makefile.
 * Host scsi ID expected to be 7 - see NCR53c7x0_init().
 *
 * I have removed the PCI code and some of the 53c8xx specific code - 
 * simply to make this file smaller and easier to manage.
 *
 * MVME16x issues:
 *   Problems trying to read any chip registers in NCR53c7x0_init(), as they
 *   may never have been set by 16xBug (eg. If kernel has come in over tftp).
 */

/*
 * Adapted for Linux/m68k Amiga platforms for the A4000T/A4091 and
 * WarpEngine SCSI controllers.
 * By Alan Hourihane <alanh@fairlite.demon.co.uk>
 * Thanks to Richard Hirst for making it possible with the MVME additions
 */

/*
 * 53c710 rev 0 doesn't support add with carry.  Rev 1 and 2 does.  To
 * overcome this problem you can define FORCE_DSA_ALIGNMENT, which ensures
 * that the DSA address is always xxxxxx00.  If disconnection is not allowed,
 * then the script only ever tries to add small (< 256) positive offsets to
 * DSA, so lack of carry isn't a problem.  FORCE_DSA_ALIGNMENT can, of course,
 * be defined for all chip revisions at a small cost in memory usage.
 */

#define FORCE_DSA_ALIGNMENT

/*
 * Selection timer does not always work on the 53c710, depending on the
 * timing at the last disconnect, if this is a problem for you, try
 * using validids as detailed below.
 *
 * Options for the NCR7xx driver
 *
 * noasync:0            -       disables sync and asynchronous negotiation
 * nosync:0             -       disables synchronous negotiation (does async)
 * nodisconnect:0       -       disables disconnection
 * validids:0x??        -       Bitmask field that disallows certain ID's.
 *                      -       e.g.    0x03    allows ID 0,1
 *                      -               0x1F    allows ID 0,1,2,3,4
 * opthi:n              -       replace top word of options with 'n'
 * optlo:n              -       replace bottom word of options with 'n'
 *                      -       ALWAYS SPECIFY opthi THEN optlo <<<<<<<<<<
 */

/*
 * PERM_OPTIONS are driver options which will be enabled for all NCR boards
 * in the system at driver initialization time.
 *
 * Don't THINK about touching these in PERM_OPTIONS : 
 *   OPTION_MEMORY_MAPPED 
 *      680x0 doesn't have an IO map!
 *
 *   OPTION_DEBUG_TEST1
 *      Test 1 does bus mastering and interrupt tests, which will help weed 
 *      out brain damaged main boards.
 *
 * Other PERM_OPTIONS settings are listed below.  Note the actual options
 * required are set in the relevant file (mvme16x.c, amiga7xx.c, etc):
 *
 *   OPTION_NO_ASYNC
 *      Don't negotiate for asynchronous transfers on the first command 
 *      when OPTION_ALWAYS_SYNCHRONOUS is set.  Useful for dain bramaged
 *      devices which do something bad rather than sending a MESSAGE 
 *      REJECT back to us like they should if they can't cope.
 *
 *   OPTION_SYNCHRONOUS
 *      Enable support for synchronous transfers.  Target negotiated 
 *      synchronous transfers will be responded to.  To initiate 
 *      a synchronous transfer request,  call 
 *
 *          request_synchronous (hostno, target) 
 *
 *      from within KGDB.
 *
 *   OPTION_ALWAYS_SYNCHRONOUS
 *      Negotiate for synchronous transfers with every target after
 *      driver initialization or a SCSI bus reset.  This is a bit dangerous, 
 *      since there are some dain bramaged SCSI devices which will accept
 *      SDTR messages but keep talking asynchronously.
 *
 *   OPTION_DISCONNECT
 *      Enable support for disconnect/reconnect.  To change the 
 *      default setting on a given host adapter, call
 *
 *          request_disconnect (hostno, allow)
 *
 *      where allow is non-zero to allow, 0 to disallow.
 * 
 *  If you really want to run 10MHz FAST SCSI-II transfers, you should 
 *  know that the NCR driver currently ignores parity information.  Most
 *  systems do 5MHz SCSI fine.  I've seen a lot that have problems faster
 *  than 8MHz.  To play it safe, we only request 5MHz transfers.
 *
 *  If you'd rather get 10MHz transfers, edit sdtr_message and change 
 *  the fourth byte from 50 to 25.
 */

/*
 * Sponsored by 
 *      iX Multiuser Multitasking Magazine
 *      Hannover, Germany
 *      hm@ix.de
 *
 * Copyright 1993, 1994, 1995 Drew Eckhardt
 *      Visionary Computing 
 *      (Unix and Linux consulting and custom programming)
 *      drew@PoohSticks.ORG
 *      +1 (303) 786-7975
 *
 * TolerANT and SCSI SCRIPTS are registered trademarks of NCR Corporation.
 * 
 * For more information, please consult 
 *
 * NCR53C810 
 * SCSI I/O Processor
 * Programmer's Guide
 *
 * NCR 53C810
 * PCI-SCSI I/O Processor
 * Data Manual
 *
 * NCR 53C810/53C820
 * PCI-SCSI I/O Processor Design In Guide
 *
 * For literature on Symbios Logic Inc. formerly NCR, SCSI, 
 * and Communication products please call (800) 334-5454 or
 * (719) 536-3300. 
 * 
 * PCI BIOS Specification Revision
 * PCI Local Bus Specification
 * PCI System Design Guide
 *
 * PCI Special Interest Group
 * M/S HF3-15A
 * 5200 N.E. Elam Young Parkway
 * Hillsboro, Oregon 97124-6497
 * +1 (503) 696-2000 
 * +1 (800) 433-5177
 */

/*
 * Design issues : 
 * The cumulative latency needed to propagate a read/write request 
 * through the file system, buffer cache, driver stacks, SCSI host, and 
 * SCSI device is ultimately the limiting factor in throughput once we 
 * have a sufficiently fast host adapter.
 *  
 * So, to maximize performance we want to keep the ratio of latency to data 
 * transfer time to a minimum by
 * 1.  Minimizing the total number of commands sent (typical command latency
 *      including drive and bus mastering host overhead is as high as 4.5ms)
 *      to transfer a given amount of data.  
 *
 *      This is accomplished by placing no arbitrary limit on the number
 *      of scatter/gather buffers supported, since we can transfer 1K
 *      per scatter/gather buffer without Eric's cluster patches, 
 *      4K with.  
 *
 * 2.  Minimizing the number of fatal interrupts serviced, since
 *      fatal interrupts halt the SCSI I/O processor.  Basically,
 *      this means offloading the practical maximum amount of processing 
 *      to the SCSI chip.
 * 
 *      On the NCR53c810/820/720,  this is accomplished by using 
 *              interrupt-on-the-fly signals when commands complete, 
 *              and only handling fatal errors and SDTR / WDTR  messages 
 *              in the host code.
 *
 *      On the NCR53c710, interrupts are generated as on the NCR53c8x0,
 *              only the lack of a interrupt-on-the-fly facility complicates
 *              things.   Also, SCSI ID registers and commands are 
 *              bit fielded rather than binary encoded.
 *              
 *      On the NCR53c700 and NCR53c700-66, operations that are done via 
 *              indirect, table mode on the more advanced chips must be
 *              replaced by calls through a jump table which 
 *              acts as a surrogate for the DSA.  Unfortunately, this 
 *              will mean that we must service an interrupt for each 
 *              disconnect/reconnect.
 * 
 * 3.  Eliminating latency by pipelining operations at the different levels.
 *      
 *      This driver allows a configurable number of commands to be enqueued
 *      for each target/lun combination (experimentally, I have discovered
 *      that two seems to work best) and will ultimately allow for 
 *      SCSI-II tagged queuing.
 *      
 *
 * Architecture : 
 * This driver is built around a Linux queue of commands waiting to 
 * be executed, and a shared Linux/NCR array of commands to start.  Commands
 * are transferred to the array  by the run_process_issue_queue() function 
 * which is called whenever a command completes.
 *
 * As commands are completed, the interrupt routine is triggered,
 * looks for commands in the linked list of completed commands with
 * valid status, removes these commands from a list of running commands, 
 * calls the done routine, and flags their target/luns as not busy.
 *
 * Due to limitations in the intelligence of the NCR chips, certain
 * concessions are made.  In many cases, it is easier to dynamically 
 * generate/fix-up code rather than calculate on the NCR at run time.  
 * So, code is generated or fixed up for
 *
 * - Handling data transfers, using a variable number of MOVE instructions
 *      interspersed with CALL MSG_IN, WHEN MSGIN instructions.
 *
 *      The DATAIN and DATAOUT routines are separate, so that an incorrect
 *      direction can be trapped, and space isn't wasted. 
 *
 *      It may turn out that we're better off using some sort 
 *      of table indirect instruction in a loop with a variable
 *      sized table on the NCR53c710 and newer chips.
 *
 * - Checking for reselection (NCR53c710 and better)
 *
 * - Handling the details of SCSI context switches (NCR53c710 and better),
 *      such as reprogramming appropriate synchronous parameters, 
 *      removing the dsa structure from the NCR's queue of outstanding
 *      commands, etc.
 *
 */

#include <linux/module.h>

#include <linux/config.h>

#include <linux/types.h>
#include <asm/setup.h>
#include <asm/dma.h>
#include <asm/io.h>
#include <asm/system.h>
#include <linux/delay.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/mm.h>
#include <linux/ioport.h>
#include <linux/time.h>
#include <linux/blkdev.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <asm/pgtable.h>

#ifdef CONFIG_AMIGA
#include <asm/amigahw.h>
#include <asm/amigaints.h>
#include <asm/irq.h>

#define BIG_ENDIAN
#define NO_IO_SPACE
#endif

#ifdef CONFIG_MVME16x
#include <asm/mvme16xhw.h>

#define BIG_ENDIAN
#define NO_IO_SPACE
#define VALID_IDS
#endif

#ifdef CONFIG_BVME6000
#include <asm/bvme6000hw.h>

#define BIG_ENDIAN
#define NO_IO_SPACE
#define VALID_IDS
#endif

#include "scsi.h"
#include <scsi/scsi_host.h>
#include "53c7xx.h"
#include <linux/stat.h>
#include <linux/stddef.h>

#ifdef NO_IO_SPACE
/*
 * The following make the definitions in 53c7xx.h (write8, etc) smaller,
 * we don't have separate i/o space anyway.
 */
#undef inb
#undef outb
#undef inw
#undef outw
#undef inl
#undef outl
#define inb(x)          1
#define inw(x)          1
#define inl(x)          1
#define outb(x,y)       1
#define outw(x,y)       1
#define outl(x,y)       1
#endif

static int check_address (unsigned long addr, int size);
static void dump_events (struct Scsi_Host *host, int count);
static Scsi_Cmnd * return_outstanding_commands (struct Scsi_Host *host, 
    int free, int issue);
static void hard_reset (struct Scsi_Host *host);
static void ncr_scsi_reset (struct Scsi_Host *host);
static void print_lots (struct Scsi_Host *host);
static void set_synchronous (struct Scsi_Host *host, int target, int sxfer, 
    int scntl3, int now_connected);
static int datapath_residual (struct Scsi_Host *host);
static const char * sbcl_to_phase (int sbcl);
static void print_progress (Scsi_Cmnd *cmd);
static void print_queues (struct Scsi_Host *host);
static void process_issue_queue (unsigned long flags);
static int shutdown (struct Scsi_Host *host);
static void abnormal_finished (struct NCR53c7x0_cmd *cmd, int result);
static int disable (struct Scsi_Host *host);
static int NCR53c7xx_run_tests (struct Scsi_Host *host);
static irqreturn_t NCR53c7x0_intr(int irq, void *dev_id, struct pt_regs * regs);
static void NCR53c7x0_intfly (struct Scsi_Host *host);
static int ncr_halt (struct Scsi_Host *host);
static void intr_phase_mismatch (struct Scsi_Host *host, struct NCR53c7x0_cmd 
    *cmd);
static void intr_dma (struct Scsi_Host *host, struct NCR53c7x0_cmd *cmd);
static void print_dsa (struct Scsi_Host *host, u32 *dsa,
    const char *prefix);
static int print_insn (struct Scsi_Host *host, const u32 *insn,
    const char *prefix, int kernel);

static void NCR53c7xx_dsa_fixup (struct NCR53c7x0_cmd *cmd);
static void NCR53c7x0_init_fixup (struct Scsi_Host *host);
static int NCR53c7x0_dstat_sir_intr (struct Scsi_Host *host, struct 
    NCR53c7x0_cmd *cmd);
static void NCR53c7x0_soft_reset (struct Scsi_Host *host);

/* Size of event list (per host adapter) */
static int track_events = 0;
static struct Scsi_Host *first_host = NULL;     /* Head of list of NCR boards */
static Scsi_Host_Template *the_template = NULL; 

/* NCR53c710 script handling code */

#include "53c7xx_d.h"
#ifdef A_int_debug_sync
#define DEBUG_SYNC_INTR A_int_debug_sync
#endif
int NCR53c7xx_script_len = sizeof (SCRIPT);
int NCR53c7xx_dsa_len = A_dsa_end + Ent_dsa_zero - Ent_dsa_code_template;
#ifdef FORCE_DSA_ALIGNMENT
int CmdPageStart = (0 - Ent_dsa_zero - sizeof(struct NCR53c7x0_cmd)) & 0xff;
#endif

static char *setup_strings[] =
        {"","","","","","","",""};

#define MAX_SETUP_STRINGS (sizeof(setup_strings) / sizeof(char *))
#define SETUP_BUFFER_SIZE 200
static char setup_buffer[SETUP_BUFFER_SIZE];
static char setup_used[MAX_SETUP_STRINGS];

void ncr53c7xx_setup (char *str, int *ints)
{
   int i;
   char *p1, *p2;

   p1 = setup_buffer;
   *p1 = '\0';
   if (str)
      strncpy(p1, str, SETUP_BUFFER_SIZE - strlen(setup_buffer));
   setup_buffer[SETUP_BUFFER_SIZE - 1] = '\0';
   p1 = setup_buffer;
   i = 0;
   while (*p1 && (i < MAX_SETUP_STRINGS)) {
      p2 = strchr(p1, ',');
      if (p2) {
         *p2 = '\0';
         if (p1 != p2)
            setup_strings[i] = p1;
         p1 = p2 + 1;
         i++;
         }
      else {
         setup_strings[i] = p1;
         break;
         }
      }
   for (i=0; i<MAX_SETUP_STRINGS; i++)
      setup_used[i] = 0;
}


/* check_setup_strings() returns index if key found, 0 if not
 */

static int check_setup_strings(char *key, int *flags, int *val, char *buf)
{
int x;
char *cp;

   for  (x=0; x<MAX_SETUP_STRINGS; x++) {
      if (setup_used[x])
         continue;
      if (!strncmp(setup_strings[x], key, strlen(key)))
         break;
      if (!strncmp(setup_strings[x], "next", strlen("next")))
         return 0;
      }
   if (x == MAX_SETUP_STRINGS)
      return 0;
   setup_used[x] = 1;
   cp = setup_strings[x] + strlen(key);
   *val = -1;
   if (*cp != ':')
      return ++x;
   cp++;
   if ((*cp >= '0') && (*cp <= '9')) {
      *val = simple_strtoul(cp,NULL,0);
      }
   return ++x;
}



/*
 * KNOWN BUGS :
 * - There is some sort of conflict when the PPP driver is compiled with 
 *      support for 16 channels?
 * 
 * - On systems which predate the 1.3.x initialization order change,
 *      the NCR driver will cause Cannot get free page messages to appear.  
 *      These are harmless, but I don't know of an easy way to avoid them.
 *
 * - With OPTION_DISCONNECT, on two systems under unknown circumstances,
 *      we get a PHASE MISMATCH with DSA set to zero (suggests that we 
 *      are occurring somewhere in the reselection code) where 
 *      DSP=some value DCMD|DBC=same value.  
 *      
 *      Closer inspection suggests that we may be trying to execute
 *      some portion of the DSA?
 * scsi0 : handling residual transfer (+ 0 bytes from DMA FIFO)
 * scsi0 : handling residual transfer (+ 0 bytes from DMA FIFO)
 * scsi0 : no current command : unexpected phase MSGIN.
 *         DSP=0x1c46cc, DCMD|DBC=0x1c46ac, DSA=0x0
 *         DSPS=0x0, TEMP=0x1c3e70, DMODE=0x80
 * scsi0 : DSP->
 * 001c46cc : 0x001c46cc 0x00000000
 * 001c46d4 : 0x001c5ea0 0x000011f8
 *
 *      Changed the print code in the phase_mismatch handler so
 *      that we call print_lots to try to diagnose this.
 *
 */

/* 
 * Possible future direction of architecture for max performance :
 *
 * We're using a single start array for the NCR chip.  This is 
 * sub-optimal, because we cannot add a command which would conflict with 
 * an executing command to this start queue, and therefore must insert the 
 * next command for a given I/T/L combination after the first has completed;
 * incurring our interrupt latency between SCSI commands.
 *
 * To allow further pipelining of the NCR and host CPU operation, we want 
 * to set things up so that immediately on termination of a command destined 
 * for a given LUN, we get that LUN busy again.  
 * 
 * To do this, we need to add a 32 bit pointer to which is jumped to 
 * on completion of a command.  If no new command is available, this 
 * would point to the usual DSA issue queue select routine.
 *
 * If one were, it would point to a per-NCR53c7x0_cmd select routine 
 * which starts execution immediately, inserting the command at the head 
 * of the start queue if the NCR chip is selected or reselected.
 *
 * We would change so that we keep a list of outstanding commands 
 * for each unit, rather than a single running_list.  We'd insert 
 * a new command into the right running list; if the NCR didn't 
 * have something running for that yet, we'd put it in the 
 * start queue as well.  Some magic needs to happen to handle the 
 * race condition between the first command terminating before the 
 * new one is written.
 *
 * Potential for profiling : 
 * Call do_gettimeofday(struct timeval *tv) to get 800ns resolution.
 */


/*
 * TODO : 
 * 1.  To support WIDE transfers, not much needs to happen.  We
 *      should do CHMOVE instructions instead of MOVEs when
 *      we have scatter/gather segments of uneven length.  When
 *      we do this, we need to handle the case where we disconnect
 *      between segments.
 * 
 * 2.  Currently, when Icky things happen we do a FATAL().  Instead,
 *     we want to do an integrity check on the parts of the NCR hostdata
 *     structure which were initialized at boot time; FATAL() if that 
 *     fails, and otherwise try to recover.  Keep track of how many
 *     times this has happened within a single SCSI command; if it 
 *     gets excessive, then FATAL().
 *
 * 3.  Parity checking is currently disabled, and a few things should 
 *     happen here now that we support synchronous SCSI transfers :
 *     1.  On soft-reset, we shoould set the EPC (Enable Parity Checking)
 *         and AAP (Assert SATN/ on parity error) bits in SCNTL0.
 *      
 *     2.  We should enable the parity interrupt in the SIEN0 register.
 * 
 *     3.  intr_phase_mismatch() needs to believe that message out is 
 *         always an "acceptable" phase to have a mismatch in.  If 
 *         the old phase was MSG_IN, we should send a MESSAGE PARITY 
 *         error.  If the old phase was something else, we should send
 *         a INITIATOR_DETECTED_ERROR message.  Note that this could
 *         cause a RESTORE POINTERS message; so we should handle that 
 *         correctly first.  Instead, we should probably do an 
 *         initiator_abort.
 *
 * 4.  MPEE bit of CTEST4 should be set so we get interrupted if 
 *     we detect an error.
 *
 *  
 * 5.  The initial code has been tested on the NCR53c810.  I don't 
 *     have access to NCR53c700, 700-66 (Forex boards), NCR53c710
 *     (NCR Pentium systems), NCR53c720, NCR53c820, or NCR53c825 boards to 
 *     finish development on those platforms.
 *
 *     NCR53c820/825/720 - need to add wide transfer support, including WDTR 
 *              negotiation, programming of wide transfer capabilities
 *              on reselection and table indirect selection.
 *
 *     NCR53c710 - need to add fatal interrupt or GEN code for 
 *              command completion signaling.   Need to modify all 
 *              SDID, SCID, etc. registers, and table indirect select code 
 *              since these use bit fielded (ie 1<<target) instead of 
 *              binary encoded target ids.  Need to accommodate
 *              different register mappings, probably scan through
 *              the SCRIPT code and change the non SFBR register operand
 *              of all MOVE instructions.
 *
 *              It is rather worse than this actually, the 710 corrupts
 *              both TEMP and DSA when you do a MOVE MEMORY.  This
 *              screws you up all over the place.  MOVE MEMORY 4 with a
 *              destination of DSA seems to work OK, which helps some.
 *              Richard Hirst  richard@sleepie.demon.co.uk
 * 
 *     NCR53c700/700-66 - need to add code to refix addresses on 
 *              every nexus change, eliminate all table indirect code,
 *              very messy.
 *
 * 6.  The NCR53c7x0 series is very popular on other platforms that 
 *     could be running Linux - ie, some high performance AMIGA SCSI 
 *     boards use it.  
 *      
 *     So, I should include #ifdef'd code so that it is 
 *     compatible with these systems.
 *      
 *     Specifically, the little Endian assumptions I made in my 
 *     bit fields need to change, and if the NCR doesn't see memory
 *     the right way, we need to provide options to reverse words
 *     when the scripts are relocated.
 *
 * 7.  Use vremap() to access memory mapped boards.  
 */

/* 
 * Allow for simultaneous existence of multiple SCSI scripts so we 
 * can have a single driver binary for all of the family.
 *
 * - one for NCR53c700 and NCR53c700-66 chips   (not yet supported)
 * - one for rest (only the NCR53c810, 815, 820, and 825 are currently 
 *      supported)
 * 
 * So that we only need two SCSI scripts, we need to modify things so
 * that we fixup register accesses in READ/WRITE instructions, and 
 * we'll also have to accommodate the bit vs. binary encoding of IDs
 * with the 7xx chips.
 */

#define ROUNDUP(adr,type)       \
  ((void *) (((long) (adr) + sizeof(type) - 1) & ~(sizeof(type) - 1)))


/*
 * Function: issue_to_cmd
 *
 * Purpose: convert jump instruction in issue array to NCR53c7x0_cmd
 *      structure pointer.  
 *
 * Inputs; issue - pointer to start of NOP or JUMP instruction
 *      in issue array.
 *
 * Returns: pointer to command on success; 0 if opcode is NOP.
 */

static inline struct NCR53c7x0_cmd *
issue_to_cmd (struct Scsi_Host *host, struct NCR53c7x0_hostdata *hostdata,
    u32 *issue)
{
    return (issue[0] != hostdata->NOP_insn) ? 
    /* 
     * If the IF TRUE bit is set, it's a JUMP instruction.  The
     * operand is a bus pointer to the dsa_begin routine for this DSA.  The
     * dsa field of the NCR53c7x0_cmd structure starts with the 
     * DSA code template.  By converting to a virtual address,
     * subtracting the code template size, and offset of the 
     * dsa field, we end up with a pointer to the start of the 
     * structure (alternatively, we could use the 
     * dsa_cmnd field, an anachronism from when we weren't
     * sure what the relationship between the NCR structures
     * and host structures were going to be.
     */
        (struct NCR53c7x0_cmd *) ((char *) bus_to_virt (issue[1]) - 
            (hostdata->E_dsa_code_begin - hostdata->E_dsa_code_template) -
            offsetof(struct NCR53c7x0_cmd, dsa)) 
    /* If the IF TRUE bit is not set, it's a NOP */
        : NULL;
}


/* 
 * FIXME: we should junk these, in favor of synchronous_want and 
 * wide_want in the NCR53c7x0_hostdata structure.
 */

/* Template for "preferred" synchronous transfer parameters. */

static const unsigned char sdtr_message[] = {
#ifdef CONFIG_SCSI_NCR53C7xx_FAST
    EXTENDED_MESSAGE, 3 /* length */, EXTENDED_SDTR, 25 /* *4ns */, 8 /* off */
#else
    EXTENDED_MESSAGE, 3 /* length */, EXTENDED_SDTR, 50 /* *4ns */, 8 /* off */ 
#endif
};

/* Template to request asynchronous transfers */

static const unsigned char async_message[] = {
    EXTENDED_MESSAGE, 3 /* length */, EXTENDED_SDTR, 0, 0 /* asynchronous */
};

/* Template for "preferred" WIDE transfer parameters */

static const unsigned char wdtr_message[] = {
    EXTENDED_MESSAGE, 2 /* length */, EXTENDED_WDTR, 1 /* 2^1 bytes */
};

#if 0
/*
 * Function : struct Scsi_Host *find_host (int host)
 * 
 * Purpose : KGDB support function which translates a host number 
 *      to a host structure. 
 *
 * Inputs : host - number of SCSI host
 *
 * Returns : NULL on failure, pointer to host structure on success.
 */

static struct Scsi_Host *
find_host (int host) {
    struct Scsi_Host *h;
    for (h = first_host; h && h->host_no != host; h = h->next);
    if (!h) {
        printk (KERN_ALERT "scsi%d not found\n", host);
        return NULL;
    } else if (h->hostt != the_template) {
        printk (KERN_ALERT "scsi%d is not a NCR board\n", host);
        return NULL;
    }
    return h;
}

#if 0
/*
 * Function : request_synchronous (int host, int target)
 * 
 * Purpose : KGDB interface which will allow us to negotiate for 
 *      synchronous transfers.  This ill be replaced with a more 
 *      integrated function; perhaps a new entry in the scsi_host 
 *      structure, accessible via an ioctl() or perhaps /proc/scsi.
 *
 * Inputs : host - number of SCSI host; target - number of target.
 *
 * Returns : 0 when negotiation has been setup for next SCSI command,
 *      -1 on failure.
 */

static int
request_synchronous (int host, int target) {
    struct Scsi_Host *h;
    struct NCR53c7x0_hostdata *hostdata;
    unsigned long flags;
    if (target < 0) {
        printk (KERN_ALERT "target %d is bogus\n", target);
        return -1;
    }
    if (!(h = find_host (host)))
        return -1;
    else if (h->this_id == target) {
        printk (KERN_ALERT "target %d is host ID\n", target);
        return -1;
    } 
    else if (target > h->max_id) {
        printk (KERN_ALERT "target %d exceeds maximum of %d\n", target,
            h->max_id);
        return -1;
    }
    hostdata = (struct NCR53c7x0_hostdata *)h->hostdata[0];

    local_irq_save(flags);
    if (hostdata->initiate_sdtr & (1 << target)) {
        local_irq_restore(flags);
        printk (KERN_ALERT "target %d already doing SDTR\n", target);
        return -1;
    } 
    hostdata->initiate_sdtr |= (1 << target);
    local_irq_restore(flags);
    return 0;
}
#endif

/*
 * Function : request_disconnect (int host, int on_or_off)
 * 
 * Purpose : KGDB support function, tells us to allow or disallow 
 *      disconnections.
 *
 * Inputs : host - number of SCSI host; on_or_off - non-zero to allow,
 *      zero to disallow.
 *
 * Returns : 0 on success, *    -1 on failure.
 */

static int 
request_disconnect (int host, int on_or_off) {
    struct Scsi_Host *h;
    struct NCR53c7x0_hostdata *hostdata;
    if (!(h = find_host (host)))
        return -1;
    hostdata = (struct NCR53c7x0_hostdata *) h->hostdata[0];
    if (on_or_off) 
        hostdata->options |= OPTION_DISCONNECT;
    else
        hostdata->options &= ~OPTION_DISCONNECT;
    return 0;
}
#endif

/*
 * Function : static void NCR53c7x0_driver_init (struct Scsi_Host *host)
 *
 * Purpose : Initialize internal structures, as required on startup, or 
 *      after a SCSI bus reset.
 * 
 * Inputs : host - pointer to this host adapter's structure
 */

static void 
NCR53c7x0_driver_init (struct Scsi_Host *host) {
    struct NCR53c7x0_hostdata *hostdata = (struct NCR53c7x0_hostdata *)
        host->hostdata[0];
    int i, j;
    u32 *ncrcurrent;

    for (i = 0; i < 16; ++i) {
        hostdata->request_sense[i] = 0;
        for (j = 0; j < 8; ++j) 
            hostdata->busy[i][j] = 0;
        set_synchronous (host, i, /* sxfer */ 0, hostdata->saved_scntl3, 0);
    }
    hostdata->issue_queue = NULL;
    hostdata->running_list = hostdata->finished_queue = 
        hostdata->ncrcurrent = NULL;
    for (i = 0, ncrcurrent = (u32 *) hostdata->schedule; 
        i < host->can_queue; ++i, ncrcurrent += 2) {
        ncrcurrent[0] = hostdata->NOP_insn;
        ncrcurrent[1] = 0xdeadbeef;
    }
    ncrcurrent[0] = ((DCMD_TYPE_TCI|DCMD_TCI_OP_JUMP) << 24) | DBC_TCI_TRUE;
    ncrcurrent[1] = (u32) virt_to_bus (hostdata->script) +
        hostdata->E_wait_reselect;
    hostdata->reconnect_dsa_head = 0;
    hostdata->addr_reconnect_dsa_head = (u32) 
        virt_to_bus((void *) &(hostdata->reconnect_dsa_head));
    hostdata->expecting_iid = 0;
    hostdata->expecting_sto = 0;
    if (hostdata->options & OPTION_ALWAYS_SYNCHRONOUS) 
        hostdata->initiate_sdtr = 0xffff; 
    else
        hostdata->initiate_sdtr = 0;
    hostdata->talked_to = 0;
    hostdata->idle = 1;
}

/* 
 * Function : static int clock_to_ccf_710 (int clock)
 *
 * Purpose :  Return the clock conversion factor for a given SCSI clock.
 *
 * Inputs : clock - SCSI clock expressed in Hz.
 *
 * Returns : ccf on success, -1 on failure.
 */

static int 
clock_to_ccf_710 (int clock) {
    if (clock <= 16666666)
        return -1;
    if (clock <= 25000000)
        return 2;       /* Divide by 1.0 */
    else if (clock <= 37500000)
        return 1;       /* Divide by 1.5 */
    else if (clock <= 50000000)
        return 0;       /* Divide by 2.0 */
    else if (clock <= 66000000)
        return 3;       /* Divide by 3.0 */
    else 
        return -1;
}
    
/* 
 * Function : static int NCR53c7x0_init (struct Scsi_Host *host)
 *
 * Purpose :  initialize the internal structures for a given SCSI host
 *
 * Inputs : host - pointer to this host adapter's structure
 *
 * Preconditions : when this function is called, the chip_type 
 *      field of the hostdata structure MUST have been set.
 *
 * Returns : 0 on success, -1 on failure.
 */

int 
NCR53c7x0_init (struct Scsi_Host *host) {
    NCR53c7x0_local_declare();
    int i, ccf;
    unsigned char revision;
    struct NCR53c7x0_hostdata *hostdata = (struct NCR53c7x0_hostdata *)
        host->hostdata[0];
    /* 
     * There are some things which we need to know about in order to provide
     * a semblance of support.  Print 'em if they aren't what we expect, 
     * otherwise don't add to the noise.
     * 
     * -1 means we don't know what to expect.
     */
    int val, flags;
    char buf[32];
    int expected_id = -1;
    int expected_clock = -1;
    int uninitialized = 0;
#ifdef NO_IO_SPACE
    int expected_mapping = OPTION_MEMORY_MAPPED;
#else
    int expected_mapping = OPTION_IO_MAPPED;
#endif
    for (i=0;i<7;i++)
        hostdata->valid_ids[i] = 1;     /* Default all ID's to scan */

    /* Parse commandline flags */
    if (check_setup_strings("noasync",&flags,&val,buf))
    {
        hostdata->options |= OPTION_NO_ASYNC;
        hostdata->options &= ~(OPTION_SYNCHRONOUS | OPTION_ALWAYS_SYNCHRONOUS);
    }

    if (check_setup_strings("nosync",&flags,&val,buf))
    {
        hostdata->options &= ~(OPTION_SYNCHRONOUS | OPTION_ALWAYS_SYNCHRONOUS);
    }

    if (check_setup_strings("nodisconnect",&flags,&val,buf))
        hostdata->options &= ~OPTION_DISCONNECT;

    if (check_setup_strings("validids",&flags,&val,buf))
    {
        for (i=0;i<7;i++) 
                hostdata->valid_ids[i] = val & (1<<i);
    }
 
    if  ((i = check_setup_strings("next",&flags,&val,buf)))
    {
        while (i)
                setup_used[--i] = 1;
    }

    if (check_setup_strings("opthi",&flags,&val,buf))
        hostdata->options = (long long)val << 32;
    if (check_setup_strings("optlo",&flags,&val,buf))
        hostdata->options |= val;

    NCR53c7x0_local_setup(host);
    switch (hostdata->chip) {
    case 710:
    case 770:
        hostdata->dstat_sir_intr = NCR53c7x0_dstat_sir_intr;
        hostdata->init_save_regs = NULL;
        hostdata->dsa_fixup = NCR53c7xx_dsa_fixup;
        hostdata->init_fixup = NCR53c7x0_init_fixup;
        hostdata->soft_reset = NCR53c7x0_soft_reset;
        hostdata->run_tests = NCR53c7xx_run_tests;
        expected_clock = hostdata->scsi_clock;
        expected_id = 7;
        break;
    default:
        printk ("scsi%d : chip type of %d is not supported yet, detaching.\n",
            host->host_no, hostdata->chip);
        scsi_unregister (host);
        return -1;
    }

    /* Assign constants accessed by NCR */
    hostdata->NCR53c7xx_zero = 0;                       
    hostdata->NCR53c7xx_msg_reject = MESSAGE_REJECT;
    hostdata->NCR53c7xx_msg_abort = ABORT;
    hostdata->NCR53c7xx_msg_nop = NOP;
    hostdata->NOP_insn = (DCMD_TYPE_TCI|DCMD_TCI_OP_JUMP) << 24;
    if (expected_mapping == -1 || 
        (hostdata->options & (OPTION_MEMORY_MAPPED)) != 
        (expected_mapping & OPTION_MEMORY_MAPPED))
        printk ("scsi%d : using %s mapped access\n", host->host_no, 
            (hostdata->options & OPTION_MEMORY_MAPPED) ? "memory" : 
            "io");

    hostdata->dmode = (hostdata->chip == 700 || hostdata->chip == 70066) ? 
        DMODE_REG_00 : DMODE_REG_10;
    hostdata->istat = ((hostdata->chip / 100) == 8) ? 
        ISTAT_REG_800 : ISTAT_REG_700;

/* We have to assume that this may be the first access to the chip, so
 * we must set EA in DCNTL. */

    NCR53c7x0_write8 (DCNTL_REG, DCNTL_10_EA|DCNTL_10_COM);


/* Only the ISTAT register is readable when the NCR is running, so make 
   sure it's halted. */
    ncr_halt(host);

/* 
 * XXX - the NCR53c700 uses bitfielded registers for SCID, SDID, etc,
 *      as does the 710 with one bit per SCSI ID.  Conversely, the NCR
 *      uses a normal, 3 bit binary representation of these values.
 *
 * Get the rest of the NCR documentation, and FIND OUT where the change
 * was.
 */

#if 0
        /* May not be able to do this - chip my not have been set up yet */
        tmp = hostdata->this_id_mask = NCR53c7x0_read8(SCID_REG);
        for (host->this_id = 0; tmp != 1; tmp >>=1, ++host->this_id);
#else
        host->this_id = 7;
#endif

/*
 * Note : we should never encounter a board setup for ID0.  So,
 *      if we see ID0, assume that it was uninitialized and set it
 *      to the industry standard 7.
 */
    if (!host->this_id) {
        printk("scsi%d : initiator ID was %d, changing to 7\n",
            host->host_no, host->this_id);
        host->this_id = 7;
        hostdata->this_id_mask = 1 << 7;
        uninitialized = 1;
    };

    if (expected_id == -1 || host->this_id != expected_id)
        printk("scsi%d : using initiator ID %d\n", host->host_no,
            host->this_id);

    /*
     * Save important registers to allow a soft reset.
     */

    /*
     * CTEST7 controls cache snooping, burst mode, and support for 
     * external differential drivers.  This isn't currently used - the
     * default value may not be optimal anyway.
     * Even worse, it may never have been set up since reset.
     */
    hostdata->saved_ctest7 = NCR53c7x0_read8(CTEST7_REG) & CTEST7_SAVE;
    revision = (NCR53c7x0_read8(CTEST8_REG) & 0xF0) >> 4;
    switch (revision) {
        case 1: revision = 0;    break;
        case 2: revision = 1;    break;
        case 4: revision = 2;    break;
        case 8: revision = 3;    break;
        default: revision = 255; break;
    }

    printk("scsi%d: Revision 0x%x\n",host->host_no,revision);

    if ((revision == 0 || revision == 255) && (hostdata->options & (OPTION_SYNCHRONOUS|OPTION_DISCONNECT|OPTION_ALWAYS_SYNCHRONOUS)))
    {
        printk ("scsi%d: Disabling sync working and disconnect/reselect\n",
                                                        host->host_no);
        hostdata->options &= ~(OPTION_SYNCHRONOUS|OPTION_DISCONNECT|OPTION_ALWAYS_SYNCHRONOUS);
    }

    /*
     * On NCR53c700 series chips, DCNTL controls the SCSI clock divisor,
     * on 800 series chips, it allows for a totem-pole IRQ driver.
     * NOTE saved_dcntl currently overwritten in init function.
     * The value read here may be garbage anyway, MVME16x board at least
     * does not initialise chip if kernel arrived via tftp.
     */

    hostdata->saved_dcntl = NCR53c7x0_read8(DCNTL_REG);

    /*
     * DMODE controls DMA burst length, and on 700 series chips,
     * 286 mode and bus width  
     * NOTE:  On MVME16x, chip may have been reset, so this could be a
     * power-on/reset default value.
     */
    hostdata->saved_dmode = NCR53c7x0_read8(hostdata->dmode);

    /* 
     * Now that burst length and enabled/disabled status is known, 
     * clue the user in on it.  
     */
   
    ccf = clock_to_ccf_710 (expected_clock);

    for (i = 0; i < 16; ++i) 
        hostdata->cmd_allocated[i] = 0;

    if (hostdata->init_save_regs)
        hostdata->init_save_regs (host);
    if (hostdata->init_fixup)
        hostdata->init_fixup (host);

    if (!the_template) {
        the_template = host->hostt;
        first_host = host;
    }

    /* 
     * Linux SCSI drivers have always been plagued with initialization 
     * problems - some didn't work with the BIOS disabled since they expected
     * initialization from it, some didn't work when the networking code
     * was enabled and registers got scrambled, etc.
     *
     * To avoid problems like this, in the future, we will do a soft 
     * reset on the SCSI chip, taking it back to a sane state.
     */

    hostdata->soft_reset (host);

#if 1
    hostdata->debug_count_limit = -1;
#else
    hostdata->debug_count_limit = 1;
#endif
    hostdata->intrs = -1;
    hostdata->resets = -1;
    memcpy ((void *) hostdata->synchronous_want, (void *) sdtr_message, 
        sizeof (hostdata->synchronous_want));

    NCR53c7x0_driver_init (host);

    if (request_irq(host->irq, NCR53c7x0_intr, SA_SHIRQ, "53c7xx", host))
    {
        printk("scsi%d : IRQ%d not free, detaching\n",
                host->host_no, host->irq);
        goto err_unregister;
    } 

    if ((hostdata->run_tests && hostdata->run_tests(host) == -1) ||
        (hostdata->options & OPTION_DEBUG_TESTS_ONLY)) {
        /* XXX Should disable interrupts, etc. here */
        goto err_free_irq;
    } else {
        if (host->io_port)  {
            host->n_io_port = 128;
            if (!request_region (host->io_port, host->n_io_port, "ncr53c7xx"))
                goto err_free_irq;
        }
    }
    
    if (NCR53c7x0_read8 (SBCL_REG) & SBCL_BSY) {
        printk ("scsi%d : bus wedge, doing SCSI reset\n", host->host_no);
        hard_reset (host);
    }
    return 0;

 err_free_irq:
    free_irq(host->irq,  NCR53c7x0_intr);
 err_unregister:
    scsi_unregister(host);
    return -1;
}

/* 
 * Function : int ncr53c7xx_init(Scsi_Host_Template *tpnt, int board, int chip,
 *      unsigned long base, int io_port, int irq, int dma, long long options,
 *      int clock);
 *
 * Purpose : initializes a NCR53c7,8x0 based on base addresses,
 *      IRQ, and DMA channel.   
 *      
 * Inputs : tpnt - Template for this SCSI adapter, board - board level
 *      product, chip - 710
 * 
 * Returns : 0 on success, -1 on failure.
 *
 */

int 
ncr53c7xx_init (Scsi_Host_Template *tpnt, int board, int chip,
    unsigned long base, int io_port, int irq, int dma, 
    long long options, int clock)
{
    struct Scsi_Host *instance;
    struct NCR53c7x0_hostdata *hostdata;
    char chip_str[80];
    int script_len = 0, dsa_len = 0, size = 0, max_cmd_size = 0,
        schedule_size = 0, ok = 0;
    void *tmp;
    unsigned long page;

    switch (chip) {
    case 710:
    case 770:
        schedule_size = (tpnt->can_queue + 1) * 8 /* JUMP instruction size */;
        script_len = NCR53c7xx_script_len;
        dsa_len = NCR53c7xx_dsa_len;
        options |= OPTION_INTFLY;
        sprintf (chip_str, "NCR53c%d", chip);
        break;
    default:
        printk("scsi-ncr53c7xx : unsupported SCSI chip %d\n", chip);
        return -1;
    }

    printk("scsi-ncr53c7xx : %s at memory 0x%lx, io 0x%x, irq %d",
        chip_str, base, io_port, irq);
    if (dma == DMA_NONE)
        printk("\n");
    else 
        printk(", dma %d\n", dma);

    if (options & OPTION_DEBUG_PROBE_ONLY) {
        printk ("scsi-ncr53c7xx : probe only enabled, aborting initialization\n");
        return -1;
    }

    max_cmd_size = sizeof(struct NCR53c7x0_cmd) + dsa_len +
        /* Size of dynamic part of command structure : */
        2 * /* Worst case : we don't know if we need DATA IN or DATA out */
                ( 2 * /* Current instructions per scatter/gather segment */ 
                  tpnt->sg_tablesize + 
                  3 /* Current startup / termination required per phase */
                ) *
        8 /* Each instruction is eight bytes */;

    /* Allocate fixed part of hostdata, dynamic part to hold appropriate
       SCSI SCRIPT(tm) plus a single, maximum-sized NCR53c7x0_cmd structure.

       We need a NCR53c7x0_cmd structure for scan_scsis() when we are 
       not loaded as a module, and when we're loaded as a module, we 
       can't use a non-dynamically allocated structure because modules
       are vmalloc()'d, which can allow structures to cross page 
       boundaries and breaks our physical/virtual address assumptions
       for DMA.

       So, we stick it past the end of our hostdata structure.

       ASSUMPTION : 
         Regardless of how many simultaneous SCSI commands we allow,
         the probe code only executes a _single_ instruction at a time,
         so we only need one here, and don't need to allocate NCR53c7x0_cmd
         structures for each target until we are no longer in scan_scsis
         and kmalloc() has become functional (memory_init() happens 
         after all device driver initialization).
    */

    size = sizeof(struct NCR53c7x0_hostdata) + script_len + 
    /* Note that alignment will be guaranteed, since we put the command
       allocated at probe time after the fixed-up SCSI script, which 
       consists of 32 bit words, aligned on a 32 bit boundary.  But
       on a 64bit machine we need 8 byte alignment for hostdata->free, so
       we add in another 4 bytes to take care of potential misalignment
       */
        (sizeof(void *) - sizeof(u32)) + max_cmd_size + schedule_size;

    page = __get_free_pages(GFP_ATOMIC,1);
    if(page==0)
    {
        printk(KERN_ERR "53c7xx: out of memory.\n");
        return -ENOMEM;
    }
#ifdef FORCE_DSA_ALIGNMENT
    /*
     * 53c710 rev.0 doesn't have an add-with-carry instruction.
     * Ensure we allocate enough memory to force DSA alignment.
    */
    size += 256;
#endif
    /* Size should be < 8K, so we can fit it in two pages. */
    if (size > 8192) {
      printk(KERN_ERR "53c7xx: hostdata > 8K\n");
      return -1;
    }

    instance = scsi_register (tpnt, 4);
    if (!instance)
    {
        free_page(page);
        return -1;
    }
    instance->hostdata[0] = page;
    memset((void *)instance->hostdata[0], 0, 8192);
    cache_push(virt_to_phys((void *)(instance->hostdata[0])), 8192);
    cache_clear(virt_to_phys((void *)(instance->hostdata[0])), 8192);
    kernel_set_cachemode((void *)instance->hostdata[0], 8192, IOMAP_NOCACHE_SER);

    /* FIXME : if we ever support an ISA NCR53c7xx based board, we
       need to check if the chip is running in a 16 bit mode, and if so 
       unregister it if it is past the 16M (0x1000000) mark */

    hostdata = (struct NCR53c7x0_hostdata *)instance->hostdata[0];
    hostdata->size = size;
    hostdata->script_count = script_len / sizeof(u32);
    hostdata->board = board;
    hostdata->chip = chip;

    /*
     * Being memory mapped is more desirable, since 
     *
     * - Memory accesses may be faster.
     *
     * - The destination and source address spaces are the same for 
     *   all instructions, meaning we don't have to twiddle dmode or 
     *   any other registers.
     *
     * So, we try for memory mapped, and if we don't get it,
     * we go for port mapped, and that failing we tell the user
     * it can't work.
     */

    if (base) {
        instance->base = base;
        /* Check for forced I/O mapping */
        if (!(options & OPTION_IO_MAPPED)) {
            options |= OPTION_MEMORY_MAPPED;
            ok = 1;
        }
    } else {
        options &= ~OPTION_MEMORY_MAPPED;
    }

    if (io_port) {
        instance->io_port = io_port;
        options |= OPTION_IO_MAPPED;
        ok = 1;
    } else {
        options &= ~OPTION_IO_MAPPED;
    }

    if (!ok) {
        printk ("scsi%d : not initializing, no I/O or memory mapping known \n",
            instance->host_no);
        scsi_unregister (instance);
        return -1;
    }
    instance->irq = irq;
    instance->dma_channel = dma;

    hostdata->options = options;
    hostdata->dsa_len = dsa_len;
    hostdata->max_cmd_size = max_cmd_size;
    hostdata->num_cmds = 1;
    hostdata->scsi_clock = clock;
    /* Initialize single command */
    tmp = (hostdata->script + hostdata->script_count);
#ifdef FORCE_DSA_ALIGNMENT
    {
        void *t = ROUNDUP(tmp, void *);
        if (((u32)t & 0xff) > CmdPageStart)
            t = (void *)((u32)t + 255);
        t = (void *)(((u32)t & ~0xff) + CmdPageStart);
        hostdata->free = t;
#if 0
        printk ("scsi: Registered size increased by 256 to %d\n", size);
        printk ("scsi: CmdPageStart = 0x%02x\n", CmdPageStart);
        printk ("scsi: tmp = 0x%08x, hostdata->free set to 0x%08x\n",
                        (u32)tmp, (u32)t);
#endif
    }
#else
    hostdata->free = ROUNDUP(tmp, void *);
#endif
    hostdata->free->real = tmp;
    hostdata->free->size = max_cmd_size;
    hostdata->free->free = NULL;
    hostdata->free->next = NULL;
    hostdata->extra_allocate = 0;

    /* Allocate command start code space */
    hostdata->schedule = (chip == 700 || chip == 70066) ?
        NULL : (u32 *) ((char *)hostdata->free + max_cmd_size);

/* 
 * For diagnostic purposes, we don't really care how fast things blaze.
 * For profiling, we want to access the 800ns resolution system clock,
 * using a 'C' call on the host processor.
 *
 * Therefore, there's no need for the NCR chip to directly manipulate
 * this data, and we should put it wherever is most convenient for 
 * Linux.
 */
    if (track_events) 
        hostdata->events = (struct NCR53c7x0_event *) (track_events ? 
            vmalloc (sizeof (struct NCR53c7x0_event) * track_events) : NULL);
    else
        hostdata->events = NULL;

    if (hostdata->events) {
        memset ((void *) hostdata->events, 0, sizeof(struct NCR53c7x0_event) *
            track_events);      
        hostdata->event_size = track_events;
        hostdata->event_index = 0;
    } else 
        hostdata->event_size = 0;

    return NCR53c7x0_init(instance);
}


/* 
 * Function : static void NCR53c7x0_init_fixup (struct Scsi_Host *host)
 *
 * Purpose :  copy and fixup the SCSI SCRIPTS(tm) code for this device.
 *
 * Inputs : host - pointer to this host adapter's structure
 *
 */

static void 
NCR53c7x0_init_fixup (struct Scsi_Host *host) {
    NCR53c7x0_local_declare();
    struct NCR53c7x0_hostdata *hostdata = (struct NCR53c7x0_hostdata *)
        host->hostdata[0];
    unsigned char tmp;
    int i, ncr_to_memory, memory_to_ncr;
    u32 base;
    NCR53c7x0_local_setup(host);


    /* XXX - NOTE : this code MUST be made endian aware */
    /*  Copy code into buffer that was allocated at detection time.  */
    memcpy ((void *) hostdata->script, (void *) SCRIPT, 
        sizeof(SCRIPT));
    /* Fixup labels */
    for (i = 0; i < PATCHES; ++i) 
        hostdata->script[LABELPATCHES[i]] += 
            virt_to_bus(hostdata->script);
    /* Fixup addresses of constants that used to be EXTERNAL */

    patch_abs_32 (hostdata->script, 0, NCR53c7xx_msg_abort, 
        virt_to_bus(&(hostdata->NCR53c7xx_msg_abort)));
    patch_abs_32 (hostdata->script, 0, NCR53c7xx_msg_reject, 
        virt_to_bus(&(hostdata->NCR53c7xx_msg_reject)));
    patch_abs_32 (hostdata->script, 0, NCR53c7xx_zero, 
        virt_to_bus(&(hostdata->NCR53c7xx_zero)));
    patch_abs_32 (hostdata->script, 0, NCR53c7xx_sink, 
        virt_to_bus(&(hostdata->NCR53c7xx_sink)));
    patch_abs_32 (hostdata->script, 0, NOP_insn,
        virt_to_bus(&(hostdata->NOP_insn)));
    patch_abs_32 (hostdata->script, 0, schedule,
        virt_to_bus((void *) hostdata->schedule));

    /* Fixup references to external variables: */
    for (i = 0; i < EXTERNAL_PATCHES_LEN; ++i)
       hostdata->script[EXTERNAL_PATCHES[i].offset] +=
         virt_to_bus(EXTERNAL_PATCHES[i].address);

    /* 
     * Fixup absolutes set at boot-time.
     * 
     * All non-code absolute variables suffixed with "dsa_" and "int_"
     * are constants, and need no fixup provided the assembler has done 
     * it for us (I don't know what the "real" NCR assembler does in 
     * this case, my assembler does the right magic).
     */

    patch_abs_rwri_data (hostdata->script, 0, dsa_save_data_pointer, 
        Ent_dsa_code_save_data_pointer - Ent_dsa_zero);
    patch_abs_rwri_data (hostdata->script, 0, dsa_restore_pointers,
        Ent_dsa_code_restore_pointers - Ent_dsa_zero);
    patch_abs_rwri_data (hostdata->script, 0, dsa_check_reselect,
        Ent_dsa_code_check_reselect - Ent_dsa_zero);

    /*
     * Just for the hell of it, preserve the settings of 
     * Burst Length and Enable Read Line bits from the DMODE 
     * register.  Make sure SCRIPTS start automagically.
     */

#if defined(CONFIG_MVME16x) || defined(CONFIG_BVME6000)
    /* We know better what we want than 16xBug does! */
    tmp = DMODE_10_BL_8 | DMODE_10_FC2;
#else
    tmp = NCR53c7x0_read8(DMODE_REG_10);
    tmp &= (DMODE_BL_MASK | DMODE_10_FC2 | DMODE_10_FC1 | DMODE_710_PD |
                                                                DMODE_710_UO);
#endif

    if (!(hostdata->options & OPTION_MEMORY_MAPPED)) {
        base = (u32) host->io_port;
        memory_to_ncr = tmp|DMODE_800_DIOM;
        ncr_to_memory = tmp|DMODE_800_SIOM;
    } else {
        base = virt_to_bus((void *)host->base);
        memory_to_ncr = ncr_to_memory = tmp;
    }

    /* SCRATCHB_REG_10 == SCRATCHA_REG_800, as it happens */
    patch_abs_32 (hostdata->script, 0, addr_scratch, base + SCRATCHA_REG_800);
    patch_abs_32 (hostdata->script, 0, addr_temp, base + TEMP_REG);
    patch_abs_32 (hostdata->script, 0, addr_dsa, base + DSA_REG);

    /*
     * I needed some variables in the script to be accessible to 
     * both the NCR chip and the host processor. For these variables,
     * I made the arbitrary decision to store them directly in the 
     * hostdata structure rather than in the RELATIVE area of the 
     * SCRIPTS.
     */
    

    patch_abs_rwri_data (hostdata->script, 0, dmode_memory_to_memory, tmp);
    patch_abs_rwri_data (hostdata->script, 0, dmode_memory_to_ncr, memory_to_ncr);
    patch_abs_rwri_data (hostdata->script, 0, dmode_ncr_to_memory, ncr_to_memory);

    patch_abs_32 (hostdata->script, 0, msg_buf, 
        virt_to_bus((void *)&(hostdata->msg_buf)));
    patch_abs_32 (hostdata->script, 0, reconnect_dsa_head, 
        virt_to_bus((void *)&(hostdata->reconnect_dsa_head)));
    patch_abs_32 (hostdata->script, 0, addr_reconnect_dsa_head, 
        virt_to_bus((void *)&(hostdata->addr_reconnect_dsa_head)));
    patch_abs_32 (hostdata->script, 0, reselected_identify, 
        virt_to_bus((void *)&(hostdata->reselected_identify)));
/* reselected_tag is currently unused */
#if 0
    patch_abs_32 (hostdata->script, 0, reselected_tag, 
        virt_to_bus((void *)&(hostdata->reselected_tag)));
#endif

    patch_abs_32 (hostdata->script, 0, test_dest, 
        virt_to_bus((void*)&hostdata->test_dest));
    patch_abs_32 (hostdata->script, 0, test_src, 
        virt_to_bus(&hostdata->test_source));
    patch_abs_32 (hostdata->script, 0, saved_dsa,
        virt_to_bus((void *)&hostdata->saved2_dsa));
    patch_abs_32 (hostdata->script, 0, emulfly,
        virt_to_bus((void *)&hostdata->emulated_intfly));

    patch_abs_rwri_data (hostdata->script, 0, dsa_check_reselect, 
        (unsigned char)(Ent_dsa_code_check_reselect - Ent_dsa_zero));

/* These are for event logging; the ncr_event enum contains the 
   actual interrupt numbers. */
#ifdef A_int_EVENT_SELECT
   patch_abs_32 (hostdata->script, 0, int_EVENT_SELECT, (u32) EVENT_SELECT);
#endif
#ifdef A_int_EVENT_DISCONNECT
   patch_abs_32 (hostdata->script, 0, int_EVENT_DISCONNECT, (u32) EVENT_DISCONNECT);
#endif
#ifdef A_int_EVENT_RESELECT
   patch_abs_32 (hostdata->script, 0, int_EVENT_RESELECT, (u32) EVENT_RESELECT);
#endif
#ifdef A_int_EVENT_COMPLETE
   patch_abs_32 (hostdata->script, 0, int_EVENT_COMPLETE, (u32) EVENT_COMPLETE);
#endif
#ifdef A_int_EVENT_IDLE
   patch_abs_32 (hostdata->script, 0, int_EVENT_IDLE, (u32) EVENT_IDLE);
#endif
#ifdef A_int_EVENT_SELECT_FAILED
   patch_abs_32 (hostdata->script, 0, int_EVENT_SELECT_FAILED, 
        (u32) EVENT_SELECT_FAILED);
#endif
#ifdef A_int_EVENT_BEFORE_SELECT
   patch_abs_32 (hostdata->script, 0, int_EVENT_BEFORE_SELECT,
        (u32) EVENT_BEFORE_SELECT);
#endif
#ifdef A_int_EVENT_RESELECT_FAILED
   patch_abs_32 (hostdata->script, 0, int_EVENT_RESELECT_FAILED, 
        (u32) EVENT_RESELECT_FAILED);
#endif

    /*
     * Make sure the NCR and Linux code agree on the location of 
     * certain fields.
     */

    hostdata->E_accept_message = Ent_accept_message;
    hostdata->E_command_complete = Ent_command_complete;                
    hostdata->E_cmdout_cmdout = Ent_cmdout_cmdout;
    hostdata->E_data_transfer = Ent_data_transfer;
    hostdata->E_debug_break = Ent_debug_break;  
    hostdata->E_dsa_code_template = Ent_dsa_code_template;
    hostdata->E_dsa_code_template_end = Ent_dsa_code_template_end;
    hostdata->E_end_data_transfer = Ent_end_data_transfer;
    hostdata->E_initiator_abort = Ent_initiator_abort;
    hostdata->E_msg_in = Ent_msg_in;
    hostdata->E_other_transfer = Ent_other_transfer;
    hostdata->E_other_in = Ent_other_in;
    hostdata->E_other_out = Ent_other_out;
    hostdata->E_reject_message = Ent_reject_message;
    hostdata->E_respond_message = Ent_respond_message;
    hostdata->E_select = Ent_select;
    hostdata->E_select_msgout = Ent_select_msgout;
    hostdata->E_target_abort = Ent_target_abort;
#ifdef Ent_test_0
    hostdata->E_test_0 = Ent_test_0;
#endif
    hostdata->E_test_1 = Ent_test_1;
    hostdata->E_test_2 = Ent_test_2;
#ifdef Ent_test_3
    hostdata->E_test_3 = Ent_test_3;
#endif
    hostdata->E_wait_reselect = Ent_wait_reselect;
    hostdata->E_dsa_code_begin = Ent_dsa_code_begin;

    hostdata->dsa_cmdout = A_dsa_cmdout;
    hostdata->dsa_cmnd = A_dsa_cmnd;
    hostdata->dsa_datain = A_dsa_datain;
    hostdata->dsa_dataout = A_dsa_dataout;
    hostdata->dsa_end = A_dsa_end;                      
    hostdata->dsa_msgin = A_dsa_msgin;
    hostdata->dsa_msgout = A_dsa_msgout;
    hostdata->dsa_msgout_other = A_dsa_msgout_other;
    hostdata->dsa_next = A_dsa_next;
    hostdata->dsa_select = A_dsa_select;
    hostdata->dsa_start = Ent_dsa_code_template - Ent_dsa_zero;
    hostdata->dsa_status = A_dsa_status;
    hostdata->dsa_jump_dest = Ent_dsa_code_fix_jump - Ent_dsa_zero + 
        8 /* destination operand */;

    /* sanity check */
    if (A_dsa_fields_start != Ent_dsa_code_template_end - 
        Ent_dsa_zero) 
        printk("scsi%d : NCR dsa_fields start is %d not %d\n",
            host->host_no, A_dsa_fields_start, Ent_dsa_code_template_end - 
            Ent_dsa_zero);

    printk("scsi%d : NCR code relocated to 0x%lx (virt 0x%p)\n", host->host_no,
        virt_to_bus(hostdata->script), hostdata->script);
}

/*
 * Function : static int NCR53c7xx_run_tests (struct Scsi_Host *host)
 *
 * Purpose : run various verification tests on the NCR chip, 
 *      including interrupt generation, and proper bus mastering
 *      operation.
 * 
 * Inputs : host - a properly initialized Scsi_Host structure
 *
 * Preconditions : the NCR chip must be in a halted state.
 *
 * Returns : 0 if all tests were successful, -1 on error.
 * 
 */

static int 
NCR53c7xx_run_tests (struct Scsi_Host *host) {
    NCR53c7x0_local_declare();
    struct NCR53c7x0_hostdata *hostdata = (struct NCR53c7x0_hostdata *)
        host->hostdata[0];
    unsigned long timeout;
    u32 start;
    int failed, i;
    unsigned long flags;
    NCR53c7x0_local_setup(host);

    /* The NCR chip _must_ be idle to run the test scripts */

    local_irq_save(flags);
    if (!hostdata->idle) {
        printk ("scsi%d : chip not idle, aborting tests\n", host->host_no);
        local_irq_restore(flags);
        return -1;
    }

    /* 
     * Check for functional interrupts, this could work as an
     * autoprobe routine.
     */

    if ((hostdata->options & OPTION_DEBUG_TEST1) && 
            hostdata->state != STATE_DISABLED) {
        hostdata->idle = 0;
        hostdata->test_running = 1;
        hostdata->test_completed = -1;
        hostdata->test_dest = 0;
        hostdata->test_source = 0xdeadbeef;
        start = virt_to_bus (hostdata->script) + hostdata->E_test_1;
        hostdata->state = STATE_RUNNING;
        printk ("scsi%d : test 1", host->host_no);
        NCR53c7x0_write32 (DSP_REG, start);
        if (hostdata->options & OPTION_DEBUG_TRACE)
            NCR53c7x0_write8 (DCNTL_REG, hostdata->saved_dcntl | DCNTL_SSM |
                                                DCNTL_STD);
        printk (" started\n");
        local_irq_restore(flags);

        /* 
         * This is currently a .5 second timeout, since (in theory) no slow 
         * board will take that long.  In practice, we've seen one 
         * pentium which occassionally fails with this, but works with 
         * 10 times as much?
         */

        timeout = jiffies + 5 * HZ / 10;
        while ((hostdata->test_completed == -1) && time_before(jiffies, timeout))
                barrier();

        failed = 1;
        if (hostdata->test_completed == -1)
            printk ("scsi%d : driver test 1 timed out%s\n",host->host_no ,
                (hostdata->test_dest == 0xdeadbeef) ? 
                    " due to lost interrupt.\n"
                    "         Please verify that the correct IRQ is being used for your board,\n"
                    : "");
        else if (hostdata->test_completed != 1) 
            printk ("scsi%d : test 1 bad interrupt value (%d)\n", 
                host->host_no, hostdata->test_completed);
        else 
            failed = (hostdata->test_dest != 0xdeadbeef);

        if (hostdata->test_dest != 0xdeadbeef) {
            printk ("scsi%d : driver test 1 read 0x%x instead of 0xdeadbeef indicating a\n"
                    "         probable cache invalidation problem.  Please configure caching\n"
                    "         as write-through or disabled\n",
                host->host_no, hostdata->test_dest);
        }

        if (failed) {
            printk ("scsi%d : DSP = 0x%p (script at 0x%p, start at 0x%x)\n",
                host->host_no, bus_to_virt(NCR53c7x0_read32(DSP_REG)),
                hostdata->script, start);
            printk ("scsi%d : DSPS = 0x%x\n", host->host_no,
                NCR53c7x0_read32(DSPS_REG));
            local_irq_restore(flags);
            return -1;
        }
        hostdata->test_running = 0;
    }

    if ((hostdata->options & OPTION_DEBUG_TEST2) && 
        hostdata->state != STATE_DISABLED) {
        u32 dsa[48];
        unsigned char identify = IDENTIFY(0, 0);
        unsigned char cmd[6];
        unsigned char data[36];
        unsigned char status = 0xff;
        unsigned char msg = 0xff;

        cmd[0] = INQUIRY;
        cmd[1] = cmd[2] = cmd[3] = cmd[5] = 0;
        cmd[4] = sizeof(data); 

        dsa[2] = 1;
        dsa[3] = virt_to_bus(&identify);
        dsa[4] = 6;
        dsa[5] = virt_to_bus(&cmd);
        dsa[6] = sizeof(data);
        dsa[7] = virt_to_bus(&data);
        dsa[8] = 1;
        dsa[9] = virt_to_bus(&status);
        dsa[10] = 1;
        dsa[11] = virt_to_bus(&msg);

        for (i = 0; i < 6; ++i) {
#ifdef VALID_IDS
            if (!hostdata->valid_ids[i])
                continue;
#endif
            local_irq_disable();
            if (!hostdata->idle) {
                printk ("scsi%d : chip not idle, aborting tests\n", host->host_no);
                local_irq_restore(flags);
                return -1;
            }

            /* 710: bit mapped scsi ID, async   */
            dsa[0] = (1 << i) << 16;
            hostdata->idle = 0;
            hostdata->test_running = 2;
            hostdata->test_completed = -1;
            start = virt_to_bus(hostdata->script) + hostdata->E_test_2;
            hostdata->state = STATE_RUNNING;
            NCR53c7x0_write32 (DSA_REG, virt_to_bus(dsa));
            NCR53c7x0_write32 (DSP_REG, start);
            if (hostdata->options & OPTION_DEBUG_TRACE)
                NCR53c7x0_write8 (DCNTL_REG, hostdata->saved_dcntl |
                                DCNTL_SSM | DCNTL_STD);
            local_irq_restore(flags);

            timeout = jiffies + 5 * HZ; /* arbitrary */
            while ((hostdata->test_completed == -1) && time_before(jiffies, timeout))
                barrier();

            NCR53c7x0_write32 (DSA_REG, 0);

            if (hostdata->test_completed == 2) {
                data[35] = 0;
                printk ("scsi%d : test 2 INQUIRY to target %d, lun 0 : %s\n",
                    host->host_no, i, data + 8);
                printk ("scsi%d : status ", host->host_no);
                print_status (status);
                printk ("\nscsi%d : message ", host->host_no);
                print_msg (&msg);
                printk ("\n");
            } else if (hostdata->test_completed == 3) {
                printk("scsi%d : test 2 no connection with target %d\n",
                    host->host_no, i);
                if (!hostdata->idle) {
                    printk("scsi%d : not idle\n", host->host_no);
                    local_irq_restore(flags);
                    return -1;
                }
            } else if (hostdata->test_completed == -1) {
                printk ("scsi%d : test 2 timed out\n", host->host_no);
                local_irq_restore(flags);
                return -1;
            } 
            hostdata->test_running = 0;
        }
    }

    local_irq_restore(flags);
    return 0;
}

/*
 * Function : static void NCR53c7xx_dsa_fixup (struct NCR53c7x0_cmd *cmd)
 *
 * Purpose : copy the NCR53c8xx dsa structure into cmd's dsa buffer,
 *      performing all necessary relocation.
 *
 * Inputs : cmd, a NCR53c7x0_cmd structure with a dsa area large
 *      enough to hold the NCR53c8xx dsa.
 */

static void 
NCR53c7xx_dsa_fixup (struct NCR53c7x0_cmd *cmd) {
    Scsi_Cmnd *c = cmd->cmd;
    struct Scsi_Host *host = c->device->host;
    struct NCR53c7x0_hostdata *hostdata = (struct NCR53c7x0_hostdata *)
        host->hostdata[0];
    int i;

    memcpy (cmd->dsa, hostdata->script + (hostdata->E_dsa_code_template / 4),
        hostdata->E_dsa_code_template_end - hostdata->E_dsa_code_template);

    /* 
     * Note : within the NCR 'C' code, dsa points to the _start_
     * of the DSA structure, and _not_ the offset of dsa_zero within
     * that structure used to facilitate shorter signed offsets
     * for the 8 bit ALU.
     * 
     * The implications of this are that 
     * 
     * - 32 bit A_dsa_* absolute values require an additional 
     *   dsa_zero added to their value to be correct, since they are 
     *   relative to dsa_zero which is in essentially a separate
     *   space from the code symbols.
     *
     * - All other symbols require no special treatment.
     */

    patch_abs_tci_data (cmd->dsa, Ent_dsa_code_template / sizeof(u32),
        dsa_temp_lun, c->device->lun);
    patch_abs_32 (cmd->dsa, Ent_dsa_code_template / sizeof(u32),
        dsa_temp_addr_next, virt_to_bus(&cmd->dsa_next_addr));
    patch_abs_32 (cmd->dsa, Ent_dsa_code_template / sizeof(u32),
        dsa_temp_next, virt_to_bus(cmd->dsa) + Ent_dsa_zero -
        Ent_dsa_code_template + A_dsa_next);
    patch_abs_32 (cmd->dsa, Ent_dsa_code_template / sizeof(u32), 
        dsa_temp_sync, virt_to_bus((void *)hostdata->sync[c->device->id].script));
    patch_abs_32 (cmd->dsa, Ent_dsa_code_template / sizeof(u32), 
        dsa_sscf_710, virt_to_bus((void *)&hostdata->sync[c->device->id].sscf_710));
    patch_abs_tci_data (cmd->dsa, Ent_dsa_code_template / sizeof(u32),
            dsa_temp_target, 1 << c->device->id);
    /* XXX - new pointer stuff */
    patch_abs_32 (cmd->dsa, Ent_dsa_code_template / sizeof(u32),
        dsa_temp_addr_saved_pointer, virt_to_bus(&cmd->saved_data_pointer));
    patch_abs_32 (cmd->dsa, Ent_dsa_code_template / sizeof(u32),
        dsa_temp_addr_saved_residual, virt_to_bus(&cmd->saved_residual));
    patch_abs_32 (cmd->dsa, Ent_dsa_code_template / sizeof(u32),
        dsa_temp_addr_residual, virt_to_bus(&cmd->residual));

    /*  XXX - new start stuff */

    patch_abs_32 (cmd->dsa, Ent_dsa_code_template / sizeof(u32),
        dsa_temp_addr_dsa_value, virt_to_bus(&cmd->dsa_addr));
}

/* 
 * Function : run_process_issue_queue (void)
 * 
 * Purpose : insure that the coroutine is running and will process our 
 *      request.  process_issue_queue_running is checked/set here (in an 
 *      inline function) rather than in process_issue_queue itself to reduce 
 *      the chances of stack overflow.
 *
 */

static volatile int process_issue_queue_running = 0;

static __inline__ void 
run_process_issue_queue(void) {
    unsigned long flags;
    local_irq_save(flags);
    if (!process_issue_queue_running) {
        process_issue_queue_running = 1;
        process_issue_queue(flags);
        /* 
         * process_issue_queue_running is cleared in process_issue_queue 
         * once it can't do more work, and process_issue_queue exits with 
         * interrupts disabled.
         */
    }
    local_irq_restore(flags);
}

/*
 * Function : static void abnormal_finished (struct NCR53c7x0_cmd *cmd, int
 *      result)
 *
 * Purpose : mark SCSI command as finished, OR'ing the host portion 
 *      of the result word into the result field of the corresponding
 *      Scsi_Cmnd structure, and removing it from the internal queues.
 *
 * Inputs : cmd - command, result - entire result field
 *
 * Preconditions : the  NCR chip should be in a halted state when 
 *      abnormal_finished is run, since it modifies structures which
 *      the NCR expects to have exclusive access to.
 */

static void 
abnormal_finished (struct NCR53c7x0_cmd *cmd, int result) {
    Scsi_Cmnd *c = cmd->cmd;
    struct Scsi_Host *host = c->device->host;
    struct NCR53c7x0_hostdata *hostdata = (struct NCR53c7x0_hostdata *)
        host->hostdata[0];
    unsigned long flags;
    int left, found;
    volatile struct NCR53c7x0_cmd * linux_search;
    volatile struct NCR53c7x0_cmd * volatile *linux_prev;
    volatile u32 *ncr_prev, *ncrcurrent, ncr_search;

#if 0
    printk ("scsi%d: abnormal finished\n", host->host_no);
#endif

    local_irq_save(flags);
    found = 0;
    /* 
     * Traverse the NCR issue array until we find a match or run out 
     * of instructions.  Instructions in the NCR issue array are 
     * either JUMP or NOP instructions, which are 2 words in length.
     */


    for (found = 0, left = host->can_queue, ncrcurrent = hostdata->schedule; 
        left > 0; --left, ncrcurrent += 2)
    {
        if (issue_to_cmd (host, hostdata, (u32 *) ncrcurrent) == cmd) 
        {
            ncrcurrent[0] = hostdata->NOP_insn;
            ncrcurrent[1] = 0xdeadbeef;
            ++found;
            break;
        }
    }
        
    /* 
     * Traverse the NCR reconnect list of DSA structures until we find 
     * a pointer to this dsa or have found too many command structures.  
     * We let prev point at the next field of the previous element or 
     * head of the list, so we don't do anything different for removing 
     * the head element.  
     */

    for (left = host->can_queue,
            ncr_search = hostdata->reconnect_dsa_head, 
            ncr_prev = &hostdata->reconnect_dsa_head;
        left >= 0 && ncr_search && 
            ((char*)bus_to_virt(ncr_search) + hostdata->dsa_start) 
                != (char *) cmd->dsa;
        ncr_prev = (u32*) ((char*)bus_to_virt(ncr_search) + 
            hostdata->dsa_next), ncr_search = *ncr_prev, --left);

    if (left < 0) 
        printk("scsi%d: loop detected in ncr reconncect list\n",
            host->host_no);
    else if (ncr_search) {
        if (found)
            printk("scsi%d: scsi %ld in ncr issue array and reconnect lists\n",
                host->host_no, c->pid);
        else {
            volatile u32 * next = (u32 *) 
                ((char *)bus_to_virt(ncr_search) + hostdata->dsa_next);
            *ncr_prev = *next;
/* If we're at the tail end of the issue queue, update that pointer too. */
            found = 1;
        }
    }

    /*
     * Traverse the host running list until we find this command or discover
     * we have too many elements, pointing linux_prev at the next field of the 
     * linux_previous element or head of the list, search at this element.
     */

    for (left = host->can_queue, linux_search = hostdata->running_list, 
            linux_prev = &hostdata->running_list;
        left >= 0 && linux_search && linux_search != cmd;
        linux_prev = &(linux_search->next), 
            linux_search = linux_search->next, --left);
    
    if (left < 0) 
        printk ("scsi%d: loop detected in host running list for scsi pid %ld\n",
            host->host_no, c->pid);
    else if (linux_search) {
        *linux_prev = linux_search->next;
        --hostdata->busy[c->device->id][c->device->lun];
    }

    /* Return the NCR command structure to the free list */
    cmd->next = hostdata->free;
    hostdata->free = cmd;
    c->host_scribble = NULL;

    /* And return */
    c->result = result;
    c->scsi_done(c);

    local_irq_restore(flags);
    run_process_issue_queue();
}

/* 
 * Function : static void intr_break (struct Scsi_Host *host,
 *      struct NCR53c7x0_cmd *cmd)
 *
 * Purpose :  Handler for breakpoint interrupts from a SCSI script
 *
 * Inputs : host - pointer to this host adapter's structure,
 *      cmd - pointer to the command (if any) dsa was pointing 
 *      to.
 *
 */

static void 
intr_break (struct Scsi_Host *host, struct 
    NCR53c7x0_cmd *cmd) {
    NCR53c7x0_local_declare();
    struct NCR53c7x0_break *bp;
#if 0
    Scsi_Cmnd *c = cmd ? cmd->cmd : NULL;
#endif
    u32 *dsp;
    struct NCR53c7x0_hostdata *hostdata = (struct NCR53c7x0_hostdata *)
        host->hostdata[0];              
    unsigned long flags;
    NCR53c7x0_local_setup(host);

    /*
     * Find the break point corresponding to this address, and 
     * dump the appropriate debugging information to standard 
     * output.  
     */
    local_irq_save(flags);
    dsp = (u32 *) bus_to_virt(NCR53c7x0_read32(DSP_REG));
    for (bp = hostdata->breakpoints; bp && bp->address != dsp; 
        bp = bp->next);
    if (!bp) 
        panic("scsi%d : break point interrupt from %p with no breakpoint!",
            host->host_no, dsp);

    /*
     * Configure the NCR chip for manual start mode, so that we can 
     * point the DSP register at the instruction that follows the 

     * INT int_debug_break instruction.
     */

    NCR53c7x0_write8 (hostdata->dmode, 
        NCR53c7x0_read8(hostdata->dmode)|DMODE_MAN);

    /*
     * And update the DSP register, using the size of the old 
     * instruction in bytes.
     */

    local_irq_restore(flags);
}
/*
 * Function : static void print_synchronous (const char *prefix, 
 *      const unsigned char *msg)
 * 
 * Purpose : print a pretty, user and machine parsable representation
 *      of a SDTR message, including the "real" parameters, data
 *      clock so we can tell transfer rate at a glance.
 *
 * Inputs ; prefix - text to prepend, msg - SDTR message (5 bytes)
 */

static void
print_synchronous (const char *prefix, const unsigned char *msg) {
    if (msg[4]) {
        int Hz = 1000000000 / (msg[3] * 4);
        int integer = Hz / 1000000;
        int fraction = (Hz - (integer * 1000000)) / 10000;
        printk ("%speriod %dns offset %d %d.%02dMHz %s SCSI%s\n",
            prefix, (int) msg[3] * 4, (int) msg[4], integer, fraction,
            (((msg[3] * 4) < 200) ? "FAST" : "synchronous"),
            (((msg[3] * 4) < 200) ? "-II" : ""));
    } else 
        printk ("%sasynchronous SCSI\n", prefix);
}

/*
 * Function : static void set_synchronous (struct Scsi_Host *host, 
 *              int target, int sxfer, int scntl3, int now_connected)
 *
 * Purpose : reprogram transfers between the selected SCSI initiator and 
 *      target with the given register values; in the indirect
 *      select operand, reselection script, and chip registers.
 *
 * Inputs : host - NCR53c7,8xx SCSI host, target - number SCSI target id,
 *      sxfer and scntl3 - NCR registers. now_connected - if non-zero, 
 *      we should reprogram the registers now too.
 *
 *      NOTE:  For 53c710, scntl3 is actually used for SCF bits from
 *      SBCL, as we don't have a SCNTL3.
 */

static void
set_synchronous (struct Scsi_Host *host, int target, int sxfer, int scntl3,
    int now_connected) {
    NCR53c7x0_local_declare();
    struct NCR53c7x0_hostdata *hostdata = (struct NCR53c7x0_hostdata *) 
        host->hostdata[0];
    u32 *script;
    NCR53c7x0_local_setup(host);

    /* These are eight bit registers */
    sxfer &= 0xff;
    scntl3 &= 0xff;

    hostdata->sync[target].sxfer_sanity = sxfer;
    hostdata->sync[target].scntl3_sanity = scntl3;

/* 
 * HARD CODED : synchronous script is EIGHT words long.  This 
 * must agree with 53c7.8xx.h
 */

    if ((hostdata->chip != 700) && (hostdata->chip != 70066)) {
        hostdata->sync[target].select_indirect = (1 << target) << 16 |
                (sxfer << 8);
        hostdata->sync[target].sscf_710 = scntl3;

        script = (u32 *) hostdata->sync[target].script;

        /* XXX - add NCR53c7x0 code to reprogram SCF bits if we want to */
        script[0] = ((DCMD_TYPE_RWRI | DCMD_RWRI_OPC_MODIFY |
                DCMD_RWRI_OP_MOVE) << 24) |
                (SBCL_REG << 16) | (scntl3 << 8);
        script[1] = 0;
        script += 2;

        script[0] = ((DCMD_TYPE_RWRI | DCMD_RWRI_OPC_MODIFY |
            DCMD_RWRI_OP_MOVE) << 24) |
                (SXFER_REG << 16) | (sxfer << 8);
        script[1] = 0;
        script += 2;

#ifdef DEBUG_SYNC_INTR
        if (hostdata->options & OPTION_DEBUG_DISCONNECT) {
            script[0] = ((DCMD_TYPE_TCI|DCMD_TCI_OP_INT) << 24) | DBC_TCI_TRUE;
            script[1] = DEBUG_SYNC_INTR;
            script += 2;
        }
#endif

        script[0] = ((DCMD_TYPE_TCI|DCMD_TCI_OP_RETURN) << 24) | DBC_TCI_TRUE;
        script[1] = 0;
        script += 2;
    }

    if (hostdata->options & OPTION_DEBUG_SYNCHRONOUS) 
        printk ("scsi%d : target %d sync parameters are sxfer=0x%x, scntl3=0x%x\n",
        host->host_no, target, sxfer, scntl3);

    if (now_connected) {
        NCR53c7x0_write8(SBCL_REG, scntl3);
        NCR53c7x0_write8(SXFER_REG, sxfer);
    }
}


/*
 * Function : static int asynchronous (struct Scsi_Host *host, int target)
 *
 * Purpose : reprogram between the selected SCSI Host adapter and target 
 *      (assumed to be currently connected) for asynchronous transfers.
 *
 * Inputs : host - SCSI host structure, target - numeric target ID.
 *
 * Preconditions : the NCR chip should be in one of the halted states
 */
    
static void
asynchronous (struct Scsi_Host *host, int target) {
    NCR53c7x0_local_declare();
    struct NCR53c7x0_hostdata *hostdata = (struct NCR53c7x0_hostdata *)
        host->hostdata[0];
    NCR53c7x0_local_setup(host);
    set_synchronous (host, target, /* no offset */ 0, hostdata->saved_scntl3,
        1);
    printk ("scsi%d : setting target %d to asynchronous SCSI\n",
        host->host_no, target);
}

/* 
 * XXX - do we want to go out of our way (ie, add extra code to selection
 *      in the NCR53c710/NCR53c720 script) to reprogram the synchronous
 *      conversion bits, or can we be content in just setting the 
 *      sxfer bits?  I chose to do so [richard@sleepie.demon.co.uk]
 */

/* Table for NCR53c8xx synchronous values */

/* This table is also correct for 710, allowing that scf=4 is equivalent
 * of SSCF=0 (ie use DCNTL, divide by 3) for a 50.01-66.00MHz clock.
 * For any other clock values, we cannot use entries with SCF values of
 * 4.  I guess that for a 66MHz clock, the slowest it will set is 2MHz,
 * and for a 50MHz clock, the slowest will be 2.27Mhz.  Should check
 * that a device doesn't try and negotiate sync below these limits!
 */
 
static const struct {
    int div;            /* Total clock divisor * 10 */
    unsigned char scf;  /* */
    unsigned char tp;   /* 4 + tp = xferp divisor */
} syncs[] = {
/*      div     scf     tp      div     scf     tp      div     scf     tp */
    {   40,     1,      0}, {   50,     1,      1}, {   60,     1,      2}, 
    {   70,     1,      3}, {   75,     2,      1}, {   80,     1,      4},
    {   90,     1,      5}, {   100,    1,      6}, {   105,    2,      3},
    {   110,    1,      7}, {   120,    2,      4}, {   135,    2,      5},
    {   140,    3,      3}, {   150,    2,      6}, {   160,    3,      4},
    {   165,    2,      7}, {   180,    3,      5}, {   200,    3,      6},
    {   210,    4,      3}, {   220,    3,      7}, {   240,    4,      4},
    {   270,    4,      5}, {   300,    4,      6}, {   330,    4,      7}
};

/*
 * Function : static void synchronous (struct Scsi_Host *host, int target, 
 *      char *msg)
 *
 * Purpose : reprogram transfers between the selected SCSI initiator and 
 *      target for synchronous SCSI transfers such that the synchronous 
 *      offset is less than that requested and period at least as long 
 *      as that requested.  Also modify *msg such that it contains 
 *      an appropriate response. 
 *
 * Inputs : host - NCR53c7,8xx SCSI host, target - number SCSI target id,
 *      msg - synchronous transfer request.
 */


static void 
synchronous (struct Scsi_Host *host, int target, char *msg) {
    struct NCR53c7x0_hostdata *hostdata = (struct NCR53c7x0_hostdata *)
        host->hostdata[0];
    int desire, divisor, i, limit;
    unsigned char scntl3, sxfer;
/* The diagnostic message fits on one line, even with max. width integers */
    char buf[80];       
   
/* Desired transfer clock in Hz */
    desire = 1000000000L / (msg[3] * 4);
/* Scale the available SCSI clock by 10 so we get tenths */
    divisor = (hostdata->scsi_clock * 10) / desire;

/* NCR chips can handle at most an offset of 8 */
    if (msg[4] > 8)
        msg[4] = 8;

    if (hostdata->options & OPTION_DEBUG_SDTR)
        printk("scsi%d : optimal synchronous divisor of %d.%01d\n", 
            host->host_no, divisor / 10, divisor % 10);

    limit = (sizeof(syncs) / sizeof(syncs[0]) -1);
    for (i = 0; (i < limit) && (divisor > syncs[i].div); ++i);

    if (hostdata->options & OPTION_DEBUG_SDTR)
        printk("scsi%d : selected synchronous divisor of %d.%01d\n", 
            host->host_no, syncs[i].div / 10, syncs[i].div % 10);

    msg[3] = ((1000000000L / hostdata->scsi_clock) * syncs[i].div / 10 / 4);

    if (hostdata->options & OPTION_DEBUG_SDTR)
        printk("scsi%d : selected synchronous period of %dns\n", host->host_no,
            msg[3] * 4);

    scntl3 = syncs[i].scf;
    sxfer = (msg[4] << SXFER_MO_SHIFT) | (syncs[i].tp << 4);
    if (hostdata->options & OPTION_DEBUG_SDTR)
        printk ("scsi%d : sxfer=0x%x scntl3=0x%x\n", 
            host->host_no, (int) sxfer, (int) scntl3);
    set_synchronous (host, target, sxfer, scntl3, 1);
    sprintf (buf, "scsi%d : setting target %d to ", host->host_no, target);
    print_synchronous (buf, msg);
}

/* 
 * Function : static int NCR53c7x0_dstat_sir_intr (struct Scsi_Host *host,
 *      struct NCR53c7x0_cmd *cmd)
 *
 * Purpose :  Handler for INT generated instructions for the 
 *      NCR53c810/820 SCSI SCRIPT
 *
 * Inputs : host - pointer to this host adapter's structure,
 *      cmd - pointer to the command (if any) dsa was pointing 
 *      to.
 *
 */

static int 
NCR53c7x0_dstat_sir_intr (struct Scsi_Host *host, struct 
    NCR53c7x0_cmd *cmd) {
    NCR53c7x0_local_declare();
    int print;
    Scsi_Cmnd *c = cmd ? cmd->cmd : NULL;
    struct NCR53c7x0_hostdata *hostdata = (struct NCR53c7x0_hostdata *)
        host->hostdata[0];              
    u32 dsps,*dsp;      /* Argument of the INT instruction */

    NCR53c7x0_local_setup(host);
    dsps = NCR53c7x0_read32(DSPS_REG);
    dsp = (u32 *) bus_to_virt(NCR53c7x0_read32(DSP_REG));

    /* RGH 150597:  Frig.  Commands which fail with Check Condition are
     * Flagged as successful - hack dsps to indicate check condition */
#if 0
    /* RGH 200597:  Need to disable for BVME6000, as it gets Check Conditions
     * and then dies.  Seems to handle Check Condition at startup, but
     * not mid kernel build. */
    if (dsps == A_int_norm_emulateintfly && cmd && cmd->result == 2)
        dsps = A_int_err_check_condition;
#endif

    if (hostdata->options & OPTION_DEBUG_INTR) 
        printk ("scsi%d : DSPS = 0x%x\n", host->host_no, dsps);

    switch (dsps) {
    case A_int_msg_1:
        print = 1;
        switch (hostdata->msg_buf[0]) {
        /* 
         * Unless we've initiated synchronous negotiation, I don't
         * think that this should happen.
         */
        case MESSAGE_REJECT:
            hostdata->dsp = hostdata->script + hostdata->E_accept_message /
                sizeof(u32);
            hostdata->dsp_changed = 1;
            if (cmd && (cmd->flags & CMD_FLAG_SDTR)) {
                printk ("scsi%d : target %d rejected SDTR\n", host->host_no, 
                    c->device->id);
                cmd->flags &= ~CMD_FLAG_SDTR;
                asynchronous (host, c->device->id);
                print = 0;
            } 
            break;
        case INITIATE_RECOVERY:
            printk ("scsi%d : extended contingent allegiance not supported yet, rejecting\n",
                host->host_no);
            /* Fall through to default */
            hostdata->dsp = hostdata->script + hostdata->E_reject_message /
                sizeof(u32);
            hostdata->dsp_changed = 1;
            break;
        default:
            printk ("scsi%d : unsupported message, rejecting\n",
                host->host_no);
            hostdata->dsp = hostdata->script + hostdata->E_reject_message /
                sizeof(u32);
            hostdata->dsp_changed = 1;
        }
        if (print) {
            printk ("scsi%d : received message", host->host_no);
            if (c) 
                printk (" from target %d lun %d ", c->device->id, c->device->lun);
            print_msg ((unsigned char *) hostdata->msg_buf);
            printk("\n");
        }
        
        return SPECIFIC_INT_NOTHING;


    case A_int_msg_sdtr:
/*
 * At this point, hostdata->msg_buf contains
 * 0 EXTENDED MESSAGE
 * 1 length 
 * 2 SDTR
 * 3 period * 4ns
 * 4 offset
 */

        if (cmd) {
            char buf[80];
            sprintf (buf, "scsi%d : target %d %s ", host->host_no, c->device->id,
                (cmd->flags & CMD_FLAG_SDTR) ? "accepting" : "requesting");
            print_synchronous (buf, (unsigned char *) hostdata->msg_buf);

        /* 
         * Initiator initiated, won't happen unless synchronous 
         *      transfers are enabled.  If we get a SDTR message in
         *      response to our SDTR, we should program our parameters
         *      such that 
         *              offset <= requested offset
         *              period >= requested period                      
         */
            if (cmd->flags & CMD_FLAG_SDTR) {
                cmd->flags &= ~CMD_FLAG_SDTR; 
                if (hostdata->msg_buf[4]) 
                    synchronous (host, c->device->id, (unsigned char *) 
                        hostdata->msg_buf);
                else 
                    asynchronous (host, c->device->id);
                hostdata->dsp = hostdata->script + hostdata->E_accept_message /
                    sizeof(u32);
                hostdata->dsp_changed = 1;
                return SPECIFIC_INT_NOTHING;
            } else {
                if (hostdata->options & OPTION_SYNCHRONOUS)  {
                    cmd->flags |= CMD_FLAG_DID_SDTR;
                    synchronous (host, c->device->id, (unsigned char *) 
                        hostdata->msg_buf);
                } else {
                    hostdata->msg_buf[4] = 0;           /* 0 offset = async */
                    asynchronous (host, c->device->id);
                }
                patch_dsa_32 (cmd->dsa, dsa_msgout_other, 0, 5);
                patch_dsa_32 (cmd->dsa, dsa_msgout_other, 1, (u32) 
                    virt_to_bus ((void *)&hostdata->msg_buf));
                hostdata->dsp = hostdata->script + 
                    hostdata->E_respond_message / sizeof(u32);
                hostdata->dsp_changed = 1;
            }
            return SPECIFIC_INT_NOTHING;
        }
        /* Fall through to abort if we couldn't find a cmd, and 
           therefore a dsa structure to twiddle */
    case A_int_msg_wdtr:
        hostdata->dsp = hostdata->script + hostdata->E_reject_message /
            sizeof(u32);
        hostdata->dsp_changed = 1;
        return SPECIFIC_INT_NOTHING;
    case A_int_err_unexpected_phase:
        if (hostdata->options & OPTION_DEBUG_INTR) 
            printk ("scsi%d : unexpected phase\n", host->host_no);
        return SPECIFIC_INT_ABORT;
    case A_int_err_selected:
        if ((hostdata->chip / 100) == 8)
            printk ("scsi%d : selected by target %d\n", host->host_no,
                (int) NCR53c7x0_read8(SDID_REG_800) &7);
        else
            printk ("scsi%d : selected by target LCRC=0x%02x\n", host->host_no,
                (int) NCR53c7x0_read8(LCRC_REG_10));
        hostdata->dsp = hostdata->script + hostdata->E_target_abort / 
            sizeof(u32);
        hostdata->dsp_changed = 1;
        return SPECIFIC_INT_NOTHING;
    case A_int_err_unexpected_reselect:
        if ((hostdata->chip / 100) == 8)
            printk ("scsi%d : unexpected reselect by target %d lun %d\n", 
                host->host_no, (int) NCR53c7x0_read8(SDID_REG_800) & 7,
                hostdata->reselected_identify & 7);
        else
            printk ("scsi%d : unexpected reselect LCRC=0x%02x\n", host->host_no,
                (int) NCR53c7x0_read8(LCRC_REG_10));
        hostdata->dsp = hostdata->script + hostdata->E_initiator_abort /
            sizeof(u32);
        hostdata->dsp_changed = 1;
        return SPECIFIC_INT_NOTHING;
/*
 * Since contingent allegiance conditions are cleared by the next 
 * command issued to a target, we must issue a REQUEST SENSE 
 * command after receiving a CHECK CONDITION status, before
 * another command is issued.
 * 
 * Since this NCR53c7x0_cmd will be freed after use, we don't 
 * care if we step on the various fields, so modify a few things.
 */
    case A_int_err_check_condition: 
#if 0
        if (hostdata->options & OPTION_DEBUG_INTR) 
#endif
            printk ("scsi%d : CHECK CONDITION\n", host->host_no);
        if (!c) {
            printk("scsi%d : CHECK CONDITION with no SCSI command\n",
                host->host_no);
            return SPECIFIC_INT_PANIC;
        }

        /* 
         * FIXME : this uses the normal one-byte selection message.
         *      We may want to renegotiate for synchronous & WIDE transfers
         *      since these could be the crux of our problem.
         *
         hostdata->NOP_insn* FIXME : once SCSI-II tagged queuing is implemented, we'll
         *      have to set this up so that the rest of the DSA
         *      agrees with this being an untagged queue'd command.
         */

        patch_dsa_32 (cmd->dsa, dsa_msgout, 0, 1);

        /* 
         * Modify the table indirect for COMMAND OUT phase, since 
         * Request Sense is a six byte command.
         */

        patch_dsa_32 (cmd->dsa, dsa_cmdout, 0, 6);

        /*
         * The CDB is now mirrored in our local non-cached
         * structure, but keep the old structure up to date as well,
         * just in case anyone looks at it.
         */

        /*
         * XXX Need to worry about data buffer alignment/cache state
         * XXX here, but currently never get A_int_err_check_condition,
         * XXX so ignore problem for now.
         */
        cmd->cmnd[0] = c->cmnd[0] = REQUEST_SENSE;
        cmd->cmnd[0] = c->cmnd[1] &= 0xe0;      /* Zero all but LUN */
        cmd->cmnd[0] = c->cmnd[2] = 0;
        cmd->cmnd[0] = c->cmnd[3] = 0;
        cmd->cmnd[0] = c->cmnd[4] = sizeof(c->sense_buffer);
        cmd->cmnd[0] = c->cmnd[5] = 0; 

        /*
         * Disable dataout phase, and program datain to transfer to the 
         * sense buffer, and add a jump to other_transfer after the 
         * command so overflow/underrun conditions are detected.
         */

        patch_dsa_32 (cmd->dsa, dsa_dataout, 0, 
            virt_to_bus(hostdata->script) + hostdata->E_other_transfer);
        patch_dsa_32 (cmd->dsa, dsa_datain, 0, 
            virt_to_bus(cmd->data_transfer_start));
        cmd->data_transfer_start[0] = (((DCMD_TYPE_BMI | DCMD_BMI_OP_MOVE_I | 
            DCMD_BMI_IO)) << 24) | sizeof(c->sense_buffer);
        cmd->data_transfer_start[1] = (u32) virt_to_bus(c->sense_buffer);

        cmd->data_transfer_start[2] = ((DCMD_TYPE_TCI | DCMD_TCI_OP_JUMP) 
            << 24) | DBC_TCI_TRUE;
        cmd->data_transfer_start[3] = (u32) virt_to_bus(hostdata->script) + 
            hostdata->E_other_transfer;

        /*
         * Currently, this command is flagged as completed, ie 
         * it has valid status and message data.  Reflag it as
         * incomplete.  Q - need to do something so that original
         * status, etc are used.
         */

        cmd->result = cmd->cmd->result = 0xffff;                

        /* 
         * Restart command as a REQUEST SENSE.
         */
        hostdata->dsp = (u32 *) hostdata->script + hostdata->E_select /
            sizeof(u32);
        hostdata->dsp_changed = 1;
        return SPECIFIC_INT_NOTHING;
    case A_int_debug_break:
        return SPECIFIC_INT_BREAK;
    case A_int_norm_aborted:
        hostdata->dsp = (u32 *) hostdata->schedule;
        hostdata->dsp_changed = 1;
        if (cmd)
            abnormal_finished (cmd, DID_ERROR << 16);
        return SPECIFIC_INT_NOTHING;
    case A_int_norm_emulateintfly:
        NCR53c7x0_intfly(host);
        return SPECIFIC_INT_NOTHING;
    case A_int_test_1:
    case A_int_test_2:
        hostdata->idle = 1;
        hostdata->test_completed = (dsps - A_int_test_1) / 0x00010000 + 1;
        if (hostdata->options & OPTION_DEBUG_INTR)
            printk("scsi%d : test%d complete\n", host->host_no,
                hostdata->test_completed);
        return SPECIFIC_INT_NOTHING;
#ifdef A_int_debug_reselected_ok
    case A_int_debug_reselected_ok:
        if (hostdata->options & (OPTION_DEBUG_SCRIPT|OPTION_DEBUG_INTR|
                OPTION_DEBUG_DISCONNECT)) {
            /* 
             * Note - this dsa is not based on location relative to 
             * the command structure, but to location relative to the 
             * DSA register 
             */ 
            u32 *dsa;
            dsa = (u32 *) bus_to_virt (NCR53c7x0_read32(DSA_REG));

            printk("scsi%d : reselected_ok (DSA = 0x%x (virt 0x%p)\n", 
                host->host_no, NCR53c7x0_read32(DSA_REG), dsa);
            printk("scsi%d : resume address is 0x%x (virt 0x%p)\n",
                    host->host_no, cmd->saved_data_pointer,
                    bus_to_virt(cmd->saved_data_pointer));
            print_insn (host, hostdata->script + Ent_reselected_ok / 
                    sizeof(u32), "", 1);
            if ((hostdata->chip / 100) == 8)
                printk ("scsi%d : sxfer=0x%x, scntl3=0x%x\n",
                    host->host_no, NCR53c7x0_read8(SXFER_REG),
                    NCR53c7x0_read8(SCNTL3_REG_800));
            else
                printk ("scsi%d : sxfer=0x%x, cannot read SBCL\n",
                    host->host_no, NCR53c7x0_read8(SXFER_REG));
            if (c) {
                print_insn (host, (u32 *) 
                    hostdata->sync[c->device->id].script, "", 1);
                print_insn (host, (u32 *) 
                    hostdata->sync[c->device->id].script + 2, "", 1);
            }
        }
        return SPECIFIC_INT_RESTART;
#endif
#ifdef A_int_debug_reselect_check
    case A_int_debug_reselect_check:
        if (hostdata->options & (OPTION_DEBUG_SCRIPT|OPTION_DEBUG_INTR)) {
            u32 *dsa;
#if 0
            u32 *code;
#endif
            /* 
             * Note - this dsa is not based on location relative to 
             * the command structure, but to location relative to the 
             * DSA register 
             */ 
            dsa = bus_to_virt (NCR53c7x0_read32(DSA_REG));
            printk("scsi%d : reselected_check_next (DSA = 0x%lx (virt 0x%p))\n",
                host->host_no, virt_to_bus(dsa), dsa);
            if (dsa) {
                printk("scsi%d : resume address is 0x%x (virt 0x%p)\n",
                    host->host_no, cmd->saved_data_pointer,
                    bus_to_virt (cmd->saved_data_pointer));
#if 0
                printk("scsi%d : template code :\n", host->host_no);
                for (code = dsa + (Ent_dsa_code_check_reselect - Ent_dsa_zero) 
                    / sizeof(u32); code < (dsa + Ent_dsa_zero / sizeof(u32)); 
                    code += print_insn (host, code, "", 1));
#endif
            }
            print_insn (host, hostdata->script + Ent_reselected_ok / 
                    sizeof(u32), "", 1);
        }
        return SPECIFIC_INT_RESTART;
#endif
#ifdef A_int_debug_dsa_schedule
    case A_int_debug_dsa_schedule:
        if (hostdata->options & (OPTION_DEBUG_SCRIPT|OPTION_DEBUG_INTR)) {
            u32 *dsa;
            /* 
             * Note - this dsa is not based on location relative to 
             * the command structure, but to location relative to the 
             * DSA register 
             */ 
            dsa = (u32 *) bus_to_virt (NCR53c7x0_read32(DSA_REG));
            printk("scsi%d : dsa_schedule (old DSA = 0x%lx (virt 0x%p))\n", 
                host->host_no, virt_to_bus(dsa), dsa);
            if (dsa) 
                printk("scsi%d : resume address is 0x%x (virt 0x%p)\n"
                       "         (temp was 0x%x (virt 0x%p))\n",
                    host->host_no, cmd->saved_data_pointer,
                    bus_to_virt (cmd->saved_data_pointer),
                    NCR53c7x0_read32 (TEMP_REG),
                    bus_to_virt (NCR53c7x0_read32(TEMP_REG)));
        }
        return SPECIFIC_INT_RESTART;
#endif
#ifdef A_int_debug_scheduled
    case A_int_debug_scheduled:
        if (hostdata->options & (OPTION_DEBUG_SCRIPT|OPTION_DEBUG_INTR)) {
            printk("scsi%d : new I/O 0x%x (virt 0x%p) scheduled\n", 
                host->host_no, NCR53c7x0_read32(DSA_REG),
                bus_to_virt(NCR53c7x0_read32(DSA_REG)));
        }
        return SPECIFIC_INT_RESTART;
#endif
#ifdef A_int_debug_idle
    case A_int_debug_idle:
        if (hostdata->options & (OPTION_DEBUG_SCRIPT|OPTION_DEBUG_INTR)) {
            printk("scsi%d : idle\n", host->host_no);
        }
        return SPECIFIC_INT_RESTART;
#endif
#ifdef A_int_debug_cmd
    case A_int_debug_cmd:
        if (hostdata->options & (OPTION_DEBUG_SCRIPT|OPTION_DEBUG_INTR)) {
            printk("scsi%d : command sent\n");
        }
        return SPECIFIC_INT_RESTART;
#endif
#ifdef A_int_debug_dsa_loaded
    case A_int_debug_dsa_loaded:
        if (hostdata->options & (OPTION_DEBUG_SCRIPT|OPTION_DEBUG_INTR)) {
            printk("scsi%d : DSA loaded with 0x%x (virt 0x%p)\n", host->host_no,
                NCR53c7x0_read32(DSA_REG), 
                bus_to_virt(NCR53c7x0_read32(DSA_REG)));
        }
        return SPECIFIC_INT_RESTART; 
#endif
#ifdef A_int_debug_reselected
    case A_int_debug_reselected:
        if (hostdata->options & (OPTION_DEBUG_SCRIPT|OPTION_DEBUG_INTR|
            OPTION_DEBUG_DISCONNECT)) {
            if ((hostdata->chip / 100) == 8)
                printk("scsi%d : reselected by target %d lun %d\n",
                    host->host_no, (int) NCR53c7x0_read8(SDID_REG_800) & ~0x80, 
                    (int) hostdata->reselected_identify & 7);
            else
                printk("scsi%d : reselected by LCRC=0x%02x lun %d\n",
                    host->host_no, (int) NCR53c7x0_read8(LCRC_REG_10),
                    (int) hostdata->reselected_identify & 7);
            print_queues(host);
        }
        return SPECIFIC_INT_RESTART;
#endif
#ifdef A_int_debug_disconnect_msg
    case A_int_debug_disconnect_msg:
        if (hostdata->options & (OPTION_DEBUG_SCRIPT|OPTION_DEBUG_INTR)) {
            if (c)
                printk("scsi%d : target %d lun %d disconnecting\n", 
                    host->host_no, c->device->id, c->device->lun);
            else
                printk("scsi%d : unknown target disconnecting\n",
                    host->host_no);
        }
        return SPECIFIC_INT_RESTART;
#endif
#ifdef A_int_debug_disconnected
    case A_int_debug_disconnected:
        if (hostdata->options & (OPTION_DEBUG_SCRIPT|OPTION_DEBUG_INTR|
                OPTION_DEBUG_DISCONNECT)) {
            printk ("scsi%d : disconnected, new queues are\n", 
                host->host_no);
            print_queues(host);
#if 0
            /* Not valid on ncr53c710! */
            printk ("scsi%d : sxfer=0x%x, scntl3=0x%x\n",
                host->host_no, NCR53c7x0_read8(SXFER_REG),
                NCR53c7x0_read8(SCNTL3_REG_800));
#endif
            if (c) {
                print_insn (host, (u32 *) 
                    hostdata->sync[c->device->id].script, "", 1);
                print_insn (host, (u32 *) 
                    hostdata->sync[c->device->id].script + 2, "", 1);
            }
        }
        return SPECIFIC_INT_RESTART;
#endif
#ifdef A_int_debug_panic
    case A_int_debug_panic:
        printk("scsi%d : int_debug_panic received\n", host->host_no);
        print_lots (host);
        return SPECIFIC_INT_PANIC;
#endif
#ifdef A_int_debug_saved
    case A_int_debug_saved:
        if (hostdata->options & (OPTION_DEBUG_SCRIPT|OPTION_DEBUG_INTR|
            OPTION_DEBUG_DISCONNECT)) {
            printk ("scsi%d : saved data pointer 0x%x (virt 0x%p)\n",
                host->host_no, cmd->saved_data_pointer,
                bus_to_virt (cmd->saved_data_pointer));
            print_progress (c);
        }
        return SPECIFIC_INT_RESTART;
#endif
#ifdef A_int_debug_restored
    case A_int_debug_restored:
        if (hostdata->options & (OPTION_DEBUG_SCRIPT|OPTION_DEBUG_INTR|
            OPTION_DEBUG_DISCONNECT)) {
            if (cmd) {
                int size;
                printk ("scsi%d : restored data pointer 0x%x (virt 0x%p)\n",
                    host->host_no, cmd->saved_data_pointer, bus_to_virt (
                    cmd->saved_data_pointer));
                size = print_insn (host, (u32 *) 
                    bus_to_virt(cmd->saved_data_pointer), "", 1);
                size = print_insn (host, (u32 *) 
                    bus_to_virt(cmd->saved_data_pointer) + size, "", 1);
                print_progress (c);
            }
#if 0
            printk ("scsi%d : datapath residual %d\n",
                host->host_no, datapath_residual (host)) ;
#endif
        }
        return SPECIFIC_INT_RESTART;
#endif
#ifdef A_int_debug_sync
    case A_int_debug_sync:
        if (hostdata->options & (OPTION_DEBUG_SCRIPT|OPTION_DEBUG_INTR|
            OPTION_DEBUG_DISCONNECT|OPTION_DEBUG_SDTR)) {
            unsigned char sxfer = NCR53c7x0_read8 (SXFER_REG), scntl3;
            if ((hostdata->chip / 100) == 8) {
                scntl3 = NCR53c7x0_read8 (SCNTL3_REG_800);
                if (c) {
                  if (sxfer != hostdata->sync[c->device->id].sxfer_sanity ||
                    scntl3 != hostdata->sync[c->device->id].scntl3_sanity) {
                        printk ("scsi%d :  sync sanity check failed sxfer=0x%x, scntl3=0x%x",
                            host->host_no, sxfer, scntl3);
                        NCR53c7x0_write8 (SXFER_REG, sxfer);
                        NCR53c7x0_write8 (SCNTL3_REG_800, scntl3);
                    }
                } else 
                  printk ("scsi%d : unknown command sxfer=0x%x, scntl3=0x%x\n",
                    host->host_no, (int) sxfer, (int) scntl3);
            } else {
                if (c) {
                  if (sxfer != hostdata->sync[c->device->id].sxfer_sanity) {
                        printk ("scsi%d :  sync sanity check failed sxfer=0x%x",
                            host->host_no, sxfer);
                        NCR53c7x0_write8 (SXFER_REG, sxfer);
                        NCR53c7x0_write8 (SBCL_REG,
                                hostdata->sync[c->device->id].sscf_710);
                    }
                } else 
                  printk ("scsi%d : unknown command sxfer=0x%x\n",
                    host->host_no, (int) sxfer);
            }
        }
        return SPECIFIC_INT_RESTART;
#endif
#ifdef A_int_debug_datain
        case A_int_debug_datain:
            if (hostdata->options & (OPTION_DEBUG_SCRIPT|OPTION_DEBUG_INTR|
                OPTION_DEBUG_DISCONNECT|OPTION_DEBUG_SDTR)) {
                int size;
                if ((hostdata->chip / 100) == 8)
                  printk ("scsi%d : In do_datain (%s) sxfer=0x%x, scntl3=0x%x\n"
                        "         datapath residual=%d\n",
                    host->host_no, sbcl_to_phase (NCR53c7x0_read8 (SBCL_REG)),
                    (int) NCR53c7x0_read8(SXFER_REG), 
                    (int) NCR53c7x0_read8(SCNTL3_REG_800),
                    datapath_residual (host)) ;
                else
                  printk ("scsi%d : In do_datain (%s) sxfer=0x%x\n"
                        "         datapath residual=%d\n",
                    host->host_no, sbcl_to_phase (NCR53c7x0_read8 (SBCL_REG)),
                    (int) NCR53c7x0_read8(SXFER_REG), 
                    datapath_residual (host)) ;
                print_insn (host, dsp, "", 1);
                size = print_insn (host, (u32 *) bus_to_virt(dsp[1]), "", 1);
                print_insn (host, (u32 *) bus_to_virt(dsp[1]) + size, "", 1);
           } 
        return SPECIFIC_INT_RESTART;
#endif
#ifdef A_int_debug_check_dsa
        case A_int_debug_check_dsa:
            if (NCR53c7x0_read8 (SCNTL1_REG) & SCNTL1_CON) {
                int sdid;
                int tmp;
                char *where;
                if (hostdata->chip / 100 == 8)
                    sdid = NCR53c7x0_read8 (SDID_REG_800) & 15;
                else {
                    tmp = NCR53c7x0_read8 (SDID_REG_700);
                    if (!tmp)
                        panic ("SDID_REG_700 = 0");
                    tmp >>= 1;
                    sdid = 0;
                    while (tmp) {
                        tmp >>= 1;
                        sdid++;
                    }
                }
                where = dsp - NCR53c7x0_insn_size(NCR53c7x0_read8 
                        (DCMD_REG)) == hostdata->script + 
                        Ent_select_check_dsa / sizeof(u32) ?
                    "selection" : "reselection";
                if (c && sdid != c->device->id) {
                    printk ("scsi%d : SDID target %d != DSA target %d at %s\n",
                        host->host_no, sdid, c->device->id, where);
                    print_lots(host);
                    dump_events (host, 20);
                    return SPECIFIC_INT_PANIC;
                }
            }
            return SPECIFIC_INT_RESTART;
#endif
    default:
        if ((dsps & 0xff000000) == 0x03000000) {
             printk ("scsi%d : misc debug interrupt 0x%x\n",
                host->host_no, dsps);
            return SPECIFIC_INT_RESTART;
        } else if ((dsps & 0xff000000) == 0x05000000) {
            if (hostdata->events) {
                struct NCR53c7x0_event *event;
                ++hostdata->event_index;
                if (hostdata->event_index >= hostdata->event_size)
                    hostdata->event_index = 0;
                event = (struct NCR53c7x0_event *) hostdata->events + 
                    hostdata->event_index;
                event->event = (enum ncr_event) dsps;
                event->dsa = bus_to_virt(NCR53c7x0_read32(DSA_REG));
                if (NCR53c7x0_read8 (SCNTL1_REG) & SCNTL1_CON) {
                    if (hostdata->chip / 100 == 8)
                        event->target = NCR53c7x0_read8(SSID_REG_800);
                    else {
                        unsigned char tmp, sdid;
                        tmp = NCR53c7x0_read8 (SDID_REG_700);
                        if (!tmp)
                            panic ("SDID_REG_700 = 0");
                        tmp >>= 1;
                        sdid = 0;
                        while (tmp) {
                            tmp >>= 1;
                            sdid++;
                        }
                        event->target = sdid;
                    }
                }
                else 
                        event->target = 255;

                if (event->event == EVENT_RESELECT)
                    event->lun = hostdata->reselected_identify & 0xf;
                else if (c)
                    event->lun = c->device->lun;
                else
                    event->lun = 255;
                do_gettimeofday(&(event->time));
                if (c) {
                    event->pid = c->pid;
                    memcpy ((void *) event->cmnd, (void *) c->cmnd, 
                        sizeof (event->cmnd));
                } else {
                    event->pid = -1;
                }
            }
            return SPECIFIC_INT_RESTART;
        }

        printk ("scsi%d : unknown user interrupt 0x%x\n", 
            host->host_no, (unsigned) dsps);
        return SPECIFIC_INT_PANIC;
    }
}

/* 
 * XXX - the stock NCR assembler won't output the scriptu.h file,
 * which undefine's all #define'd CPP symbols from the script.h
 * file, which will create problems if you use multiple scripts
 * with the same  symbol names.
 *
 * If you insist on using NCR's assembler, you could generate
 * scriptu.h from script.h using something like 
 *
 * grep #define script.h | \
 * sed 's/#define[      ][      ]*\([_a-zA-Z][_a-zA-Z0-9]*\).*$/#undefine \1/' \
 * > scriptu.h
 */

#include "53c7xx_u.h"

/* XXX - add alternate script handling code here */


/* 
 * Function : static void NCR537xx_soft_reset (struct Scsi_Host *host)
 *
 * Purpose :  perform a soft reset of the NCR53c7xx chip
 *
 * Inputs : host - pointer to this host adapter's structure
 *
 * Preconditions : NCR53c7x0_init must have been called for this 
 *      host.
 * 
 */

static void 
NCR53c7x0_soft_reset (struct Scsi_Host *host) {
    NCR53c7x0_local_declare();
    unsigned long flags;
    struct NCR53c7x0_hostdata *hostdata = (struct NCR53c7x0_hostdata *)
        host->hostdata[0];
    NCR53c7x0_local_setup(host);

    local_irq_save(flags);

    /* Disable scsi chip and s/w level 7 ints */

#ifdef CONFIG_MVME16x
    if (MACH_IS_MVME16x)
    {
        volatile unsigned long v;

        v = *(volatile unsigned long *)0xfff4006c;
        v &= ~0x8000;
        *(volatile unsigned long *)0xfff4006c = v;
        v = *(volatile unsigned long *)0xfff4202c;
        v &= ~0x10;
        *(volatile unsigned long *)0xfff4202c = v;
    }
#endif
    /* Anything specific for your hardware? */

    /*
     * Do a soft reset of the chip so that everything is 
     * reinitialized to the power-on state.
     *
     * Basically follow the procedure outlined in the NCR53c700
     * data manual under Chapter Six, How to Use, Steps Necessary to
     * Start SCRIPTS, with the exception of actually starting the 
     * script and setting up the synchronous transfer gunk.
     */

    /* Should we reset the scsi bus here??????????????????? */

    NCR53c7x0_write8(ISTAT_REG_700, ISTAT_10_SRST);
    NCR53c7x0_write8(ISTAT_REG_700, 0);

    /*
     * saved_dcntl is set up in NCR53c7x0_init() before it is overwritten
     * here.  We should have some better way of working out the CF bit
     * setting..
     */

    hostdata->saved_dcntl = DCNTL_10_EA|DCNTL_10_COM;
    if (hostdata->scsi_clock > 50000000)
        hostdata->saved_dcntl |= DCNTL_700_CF_3;
    else
    if (hostdata->scsi_clock > 37500000)
        hostdata->saved_dcntl |= DCNTL_700_CF_2;
#if 0
    else
        /* Any clocks less than 37.5MHz? */
#endif

    if (hostdata->options & OPTION_DEBUG_TRACE)
        NCR53c7x0_write8(DCNTL_REG, hostdata->saved_dcntl | DCNTL_SSM);
    else
        NCR53c7x0_write8(DCNTL_REG, hostdata->saved_dcntl);
    /* Following disables snooping - snooping is not required, as non-
     * cached pages are used for shared data, and appropriate use is
     * made of cache_push/cache_clear.  Indeed, for 68060
     * enabling snooping causes disk corruption of ext2fs free block
     * bitmaps and the like.  If you have a 68060 with snooping hardwared
     * on, then you need to enable CONFIG_060_WRITETHROUGH.
     */
    NCR53c7x0_write8(CTEST7_REG, CTEST7_10_TT1|CTEST7_STD);
    /* Actually burst of eight, according to my 53c710 databook */
    NCR53c7x0_write8(hostdata->dmode, DMODE_10_BL_8 | DMODE_10_FC2);
    NCR53c7x0_write8(SCID_REG, 1 << host->this_id);
    NCR53c7x0_write8(SBCL_REG, 0);
    NCR53c7x0_write8(SCNTL1_REG, SCNTL1_ESR_700);
    NCR53c7x0_write8(SCNTL0_REG, ((hostdata->options & OPTION_PARITY) ? 
            SCNTL0_EPC : 0) | SCNTL0_EPG_700 | SCNTL0_ARB1 | SCNTL0_ARB2);

    /*
     * Enable all interrupts, except parity which we only want when
     * the user requests it.
     */

    NCR53c7x0_write8(DIEN_REG, DIEN_700_BF |
                DIEN_ABRT | DIEN_SSI | DIEN_SIR | DIEN_700_OPC);

    NCR53c7x0_write8(SIEN_REG_700, ((hostdata->options & OPTION_PARITY) ?
            SIEN_PAR : 0) | SIEN_700_STO | SIEN_RST | SIEN_UDC |
                SIEN_SGE | SIEN_MA);

#ifdef CONFIG_MVME16x
    if (MACH_IS_MVME16x)
    {
        volatile unsigned long v;

        /* Enable scsi chip and s/w level 7 ints */
        v = *(volatile unsigned long *)0xfff40080;
        v = (v & ~(0xf << 28)) | (4 << 28);
        *(volatile unsigned long *)0xfff40080 = v;
        v = *(volatile unsigned long *)0xfff4006c;
        v |= 0x8000;
        *(volatile unsigned long *)0xfff4006c = v;
        v = *(volatile unsigned long *)0xfff4202c;
        v = (v & ~0xff) | 0x10 | 4;
        *(volatile unsigned long *)0xfff4202c = v;
    }
#endif
    /* Anything needed for your hardware? */
    local_irq_restore(flags);
}


/*
 * Function static struct NCR53c7x0_cmd *allocate_cmd (Scsi_Cmnd *cmd)
 * 
 * Purpose : Return the first free NCR53c7x0_cmd structure (which are 
 *      reused in a LIFO manner to minimize cache thrashing).
 *
 * Side effects : If we haven't yet scheduled allocation of NCR53c7x0_cmd
 *      structures for this device, do so.  Attempt to complete all scheduled
 *      allocations using get_zeroed_page(), putting NCR53c7x0_cmd structures on
 *      the free list.  Teach programmers not to drink and hack.
 *
 * Inputs : cmd - SCSI command
 *
 * Returns : NCR53c7x0_cmd structure allocated on behalf of cmd;
 *      NULL on failure.
 */

static void
my_free_page (void *addr, int dummy)
{
    /* XXX This assumes default cache mode to be IOMAP_FULL_CACHING, which
     * XXX may be invalid (CONFIG_060_WRITETHROUGH)
     */
    kernel_set_cachemode((void *)addr, 4096, IOMAP_FULL_CACHING);
    free_page ((u32)addr);
}

static struct NCR53c7x0_cmd *
allocate_cmd (Scsi_Cmnd *cmd) {
    struct Scsi_Host *host = cmd->device->host;
    struct NCR53c7x0_hostdata *hostdata = 
        (struct NCR53c7x0_hostdata *) host->hostdata[0];
    u32 real;                   /* Real address */
    int size;                   /* Size of *tmp */
    struct NCR53c7x0_cmd *tmp;
    unsigned long flags;

    if (hostdata->options & OPTION_DEBUG_ALLOCATION)
        printk ("scsi%d : num_cmds = %d, can_queue = %d\n"
                "         target = %d, lun = %d, %s\n",
            host->host_no, hostdata->num_cmds, host->can_queue,
            cmd->device->id, cmd->device->lun, (hostdata->cmd_allocated[cmd->device->id] &
                (1 << cmd->device->lun)) ? "already allocated" : "not allocated");

/*
 * If we have not yet reserved commands for this I_T_L nexus, and
 * the device exists (as indicated by permanent Scsi_Cmnd structures
 * being allocated under 1.3.x, or being outside of scan_scsis in
 * 1.2.x), do so now.
 */
    if (!(hostdata->cmd_allocated[cmd->device->id] & (1 << cmd->device->lun)) &&
                                cmd->device && cmd->device->has_cmdblocks) {
      if ((hostdata->extra_allocate + hostdata->num_cmds) < host->can_queue)
          hostdata->extra_allocate += host->cmd_per_lun;
      hostdata->cmd_allocated[cmd->device->id] |= (1 << cmd->device->lun);
    }

    for (; hostdata->extra_allocate > 0 ; --hostdata->extra_allocate, 
        ++hostdata->num_cmds) {
    /* historically, kmalloc has returned unaligned addresses; pad so we
       have enough room to ROUNDUP */
        size = hostdata->max_cmd_size + sizeof (void *);
#ifdef FORCE_DSA_ALIGNMENT
        /*
         * 53c710 rev.0 doesn't have an add-with-carry instruction.
         * Ensure we allocate enough memory to force alignment.
         */
        size += 256;
#endif
/* FIXME: for ISA bus '7xx chips, we need to or GFP_DMA in here */

        if (size > 4096) {
            printk (KERN_ERR "53c7xx: allocate_cmd size > 4K\n");
            return NULL;
        }
        real = get_zeroed_page(GFP_ATOMIC);
        if (real == 0)
                return NULL;
        memset((void *)real, 0, 4096);
        cache_push(virt_to_phys((void *)real), 4096);
        cache_clear(virt_to_phys((void *)real), 4096);
        kernel_set_cachemode((void *)real, 4096, IOMAP_NOCACHE_SER);
        tmp = ROUNDUP(real, void *);
#ifdef FORCE_DSA_ALIGNMENT
        {
            if (((u32)tmp & 0xff) > CmdPageStart)
                tmp = (struct NCR53c7x0_cmd *)((u32)tmp + 255);
            tmp = (struct NCR53c7x0_cmd *)(((u32)tmp & ~0xff) + CmdPageStart);
#if 0
            printk ("scsi: size = %d, real = 0x%08x, tmp set to 0x%08x\n",
                        size, real, (u32)tmp);
#endif
        }
#endif
        tmp->real = (void *)real;
        tmp->size = size;                       
        tmp->free = ((void (*)(void *, int)) my_free_page);
        local_irq_save(flags);
        tmp->next = hostdata->free;
        hostdata->free = tmp;
        local_irq_restore(flags);
    }
    local_irq_save(flags);
    tmp = (struct NCR53c7x0_cmd *) hostdata->free;
    if (tmp) {
        hostdata->free = tmp->next;
    }
    local_irq_restore(flags);
    if (!tmp)
        printk ("scsi%d : can't allocate command for target %d lun %d\n",
            host->host_no, cmd->device->id, cmd->device->lun);
    return tmp;
}

/*
 * Function static struct NCR53c7x0_cmd *create_cmd (Scsi_Cmnd *cmd) 
 *
 *
 * Purpose : allocate a NCR53c7x0_cmd structure, initialize it based on the 
 *      Scsi_Cmnd structure passed in cmd, including dsa and Linux field 
 *      initialization, and dsa code relocation.
 *
 * Inputs : cmd - SCSI command
 *
 * Returns : NCR53c7x0_cmd structure corresponding to cmd,
 *      NULL on failure.
 */
static struct NCR53c7x0_cmd *
create_cmd (Scsi_Cmnd *cmd) {
    NCR53c7x0_local_declare();
    struct Scsi_Host *host = cmd->device->host;
    struct NCR53c7x0_hostdata *hostdata = (struct NCR53c7x0_hostdata *)
        host->hostdata[0];      
    struct NCR53c7x0_cmd *tmp;  /* NCR53c7x0_cmd structure for this command */
    int datain,                 /* Number of instructions per phase */
        dataout;
    int data_transfer_instructions, /* Count of dynamic instructions */
        i;                      /* Counter */
    u32 *cmd_datain,            /* Address of datain/dataout code */
        *cmd_dataout;           /* Incremented as we assemble */
#ifdef notyet
    unsigned char *msgptr;      /* Current byte in select message */
    int msglen;                 /* Length of whole select message */
#endif
    unsigned long flags;
    u32 exp_select_indirect;    /* Used in sanity check */
    NCR53c7x0_local_setup(cmd->device->host);

    if (!(tmp = allocate_cmd (cmd)))
        return NULL;

    /*
     * Copy CDB and initialised result fields from Scsi_Cmnd to NCR53c7x0_cmd.
     * We do this because NCR53c7x0_cmd may have a special cache mode
     * selected to cope with lack of bus snooping, etc.
     */

    memcpy(tmp->cmnd, cmd->cmnd, 12);
    tmp->result = cmd->result;

    /*
     * Decide whether we need to generate commands for DATA IN,
     * DATA OUT, neither, or both based on the SCSI command 
     */

    switch (cmd->cmnd[0]) {
    /* These commands do DATA IN */
    case INQUIRY:
    case MODE_SENSE:
    case READ_6:
    case READ_10:
    case READ_CAPACITY:
    case REQUEST_SENSE:
    case READ_BLOCK_LIMITS:
    case READ_TOC:
        datain = 2 * (cmd->use_sg ? cmd->use_sg : 1) + 3;
        dataout = 0;
        break;
    /* These commands do DATA OUT */
    case MODE_SELECT: 
    case WRITE_6:
    case WRITE_10:
#if 0
        printk("scsi%d : command is ", host->host_no);
        print_command(cmd->cmnd);
#endif
#if 0
        printk ("scsi%d : %d scatter/gather segments\n", host->host_no,
            cmd->use_sg);
#endif
        datain = 0;
        dataout = 2 * (cmd->use_sg ? cmd->use_sg : 1) + 3;
#if 0
        hostdata->options |= OPTION_DEBUG_INTR;
#endif
        break;
    /* 
     * These commands do no data transfer, we should force an
     * interrupt if a data phase is attempted on them.
     */
    case TEST_UNIT_READY:
    case ALLOW_MEDIUM_REMOVAL:
    case START_STOP:
        datain = dataout = 0;
        break;
    /*
     * We don't know about these commands, so generate code to handle
     * both DATA IN and DATA OUT phases.  More efficient to identify them
     * and add them to the above cases.
     */
    default:
        printk("scsi%d : datain+dataout for command ", host->host_no);
        print_command(cmd->cmnd);
        datain = dataout = 2 * (cmd->use_sg ? cmd->use_sg : 1) + 3;
    }

    /*
     * New code : so that active pointers work correctly regardless
     *  of where the saved data pointer is at, we want to immediately
     *  enter the dynamic code after selection, and on a non-data
     *  phase perform a CALL to the non-data phase handler, with
     *  returns back to this address.
     *
     *  If a phase mismatch is encountered in the middle of a 
     *  Block MOVE instruction, we want to _leave_ that instruction
     *  unchanged as the current case is, modify a temporary buffer,
     *  and point the active pointer (TEMP) at that.
     *
     *  Furthermore, we want to implement a saved data pointer, 
     *  set by the SAVE_DATA_POINTERs message.
     *
     *  So, the data transfer segments will change to 
     *          CALL data_transfer, WHEN NOT data phase
     *          MOVE x, x, WHEN data phase
     *          ( repeat )
     *          JUMP other_transfer
     */

    data_transfer_instructions = datain + dataout;

    /*
     * When we perform a request sense, we overwrite various things,
     * including the data transfer code.  Make sure we have enough
     * space to do that.
     */

    if (data_transfer_instructions < 2)
        data_transfer_instructions = 2;


    /*
     * The saved data pointer is set up so that a RESTORE POINTERS message 
     * will start the data transfer over at the beginning.
     */

    tmp->saved_data_pointer = virt_to_bus (hostdata->script) + 
        hostdata->E_data_transfer;

    /*
     * Initialize Linux specific fields.
     */

    tmp->cmd = cmd;
    tmp->next = NULL;
    tmp->flags = 0;
    tmp->dsa_next_addr = virt_to_bus(tmp->dsa) + hostdata->dsa_next - 
        hostdata->dsa_start;
    tmp->dsa_addr = virt_to_bus(tmp->dsa) - hostdata->dsa_start;

    /* 
     * Calculate addresses of dynamic code to fill in DSA
     */

    tmp->data_transfer_start = tmp->dsa + (hostdata->dsa_end - 
        hostdata->dsa_start) / sizeof(u32);
    tmp->data_transfer_end = tmp->data_transfer_start + 
        2 * data_transfer_instructions;

    cmd_datain = datain ? tmp->data_transfer_start : NULL;
    cmd_dataout = dataout ? (datain ? cmd_datain + 2 * datain : tmp->
        data_transfer_start) : NULL;

    /*
     * Fill in the NCR53c7x0_cmd structure as follows
     * dsa, with fixed up DSA code
     * datain code
     * dataout code
     */

    /* Copy template code into dsa and perform all necessary fixups */
    if (hostdata->dsa_fixup)
        hostdata->dsa_fixup(tmp);

    patch_dsa_32(tmp->dsa, dsa_next, 0, 0);
    /*
     * XXX is this giving 53c710 access to the Scsi_Cmnd in some way?
     * Do we need to change it for caching reasons?
     */
    patch_dsa_32(tmp->dsa, dsa_cmnd, 0, virt_to_bus(cmd));

    if (hostdata->options & OPTION_DEBUG_SYNCHRONOUS) {

        exp_select_indirect = ((1 << cmd->device->id) << 16) |
                        (hostdata->sync[cmd->device->id].sxfer_sanity << 8);

        if (hostdata->sync[cmd->device->id].select_indirect !=
                                exp_select_indirect) {
            printk ("scsi%d :  sanity check failed select_indirect=0x%x\n",
                host->host_no, hostdata->sync[cmd->device->id].select_indirect);
            FATAL(host);

        }
    }

    patch_dsa_32(tmp->dsa, dsa_select, 0,
                hostdata->sync[cmd->device->id].select_indirect);

    /*
     * Right now, we'll do the WIDE and SYNCHRONOUS negotiations on
     * different commands; although it should be trivial to do them
     * both at the same time.
     */
    if (hostdata->initiate_wdtr & (1 << cmd->device->id)) {
        memcpy ((void *) (tmp->select + 1), (void *) wdtr_message,
            sizeof(wdtr_message));
        patch_dsa_32(tmp->dsa, dsa_msgout, 0, 1 + sizeof(wdtr_message));
        local_irq_save(flags);
        hostdata->initiate_wdtr &= ~(1 << cmd->device->id);
        local_irq_restore(flags);
    } else if (hostdata->initiate_sdtr & (1 << cmd->device->id)) {
        memcpy ((void *) (tmp->select + 1), (void *) sdtr_message, 
            sizeof(sdtr_message));
        patch_dsa_32(tmp->dsa, dsa_msgout, 0, 1 + sizeof(sdtr_message));
        tmp->flags |= CMD_FLAG_SDTR;
        local_irq_save(flags);
        hostdata->initiate_sdtr &= ~(1 << cmd->device->id);
        local_irq_restore(flags);
    
    }
#if 1
    else if (!(hostdata->talked_to & (1 << cmd->device->id)) &&
                !(hostdata->options & OPTION_NO_ASYNC)) {

        memcpy ((void *) (tmp->select + 1), (void *) async_message, 
            sizeof(async_message));
        patch_dsa_32(tmp->dsa, dsa_msgout, 0, 1 + sizeof(async_message));
        tmp->flags |= CMD_FLAG_SDTR;
    } 
#endif
    else 
        patch_dsa_32(tmp->dsa, dsa_msgout, 0, 1);

    hostdata->talked_to |= (1 << cmd->device->id);
    tmp->select[0] = (hostdata->options & OPTION_DISCONNECT) ? 
        IDENTIFY (1, cmd->device->lun) : IDENTIFY (0, cmd->device->lun);
    patch_dsa_32(tmp->dsa, dsa_msgout, 1, virt_to_bus(tmp->select));
    patch_dsa_32(tmp->dsa, dsa_cmdout, 0, cmd->cmd_len);
    patch_dsa_32(tmp->dsa, dsa_cmdout, 1, virt_to_bus(tmp->cmnd));
    patch_dsa_32(tmp->dsa, dsa_dataout, 0, cmd_dataout ? 
            virt_to_bus (cmd_dataout)
        : virt_to_bus (hostdata->script) + hostdata->E_other_transfer);
    patch_dsa_32(tmp->dsa, dsa_datain, 0, cmd_datain ? 
            virt_to_bus (cmd_datain) 
        : virt_to_bus (hostdata->script) + hostdata->E_other_transfer);
    /* 
     * XXX - need to make endian aware, should use separate variables
     * for both status and message bytes.
     */
    patch_dsa_32(tmp->dsa, dsa_msgin, 0, 1);
/* 
 * FIXME : these only works for little endian.  We probably want to 
 *      provide message and status fields in the NCR53c7x0_cmd 
 *      structure, and assign them to cmd->result when we're done.
 */
#ifdef BIG_ENDIAN
    patch_dsa_32(tmp->dsa, dsa_msgin, 1, virt_to_bus(&tmp->result) + 2);
    patch_dsa_32(tmp->dsa, dsa_status, 0, 1);
    patch_dsa_32(tmp->dsa, dsa_status, 1, virt_to_bus(&tmp->result) + 3);
#else
    patch_dsa_32(tmp->dsa, dsa_msgin, 1, virt_to_bus(&tmp->result) + 1);
    patch_dsa_32(tmp->dsa, dsa_status, 0, 1);
    patch_dsa_32(tmp->dsa, dsa_status, 1, virt_to_bus(&tmp->result));
#endif
    patch_dsa_32(tmp->dsa, dsa_msgout_other, 0, 1);
    patch_dsa_32(tmp->dsa, dsa_msgout_other, 1, 
        virt_to_bus(&(hostdata->NCR53c7xx_msg_nop)));
    
    /*
     * Generate code for zero or more of the DATA IN, DATA OUT phases 
     * in the format 
     *
     * CALL data_transfer, WHEN NOT phase
     * MOVE first buffer length, first buffer address, WHEN phase
     * ...
     * MOVE last buffer length, last buffer address, WHEN phase
     * JUMP other_transfer
     */

/* 
 * See if we're getting to data transfer by generating an unconditional 
 * interrupt.
 */
#if 0
    if (datain) {
        cmd_datain[0] = 0x98080000;
        cmd_datain[1] = 0x03ffd00d;
        cmd_datain += 2;
    }
#endif

/* 
 * XXX - I'm undecided whether all of this nonsense is faster
 * in the long run, or whether I should just go and implement a loop
 * on the NCR chip using table indirect mode?
 *
 * In any case, this is how it _must_ be done for 53c700/700-66 chips,
 * so this stays even when we come up with something better.
 *
 * When we're limited to 1 simultaneous command, no overlapping processing,
 * we're seeing 630K/sec, with 7% CPU usage on a slow Syquest 45M
 * drive.
 *
 * Not bad, not good. We'll see.
 */

    tmp->bounce.len = 0;        /* Assume aligned buffer */

    for (i = 0; cmd->use_sg ? (i < cmd->use_sg) : !i; cmd_datain += 4, 
        cmd_dataout += 4, ++i) {
        u32 vbuf = cmd->use_sg
            ? (u32)page_address(((struct scatterlist *)cmd->buffer)[i].page)+
              ((struct scatterlist *)cmd->buffer)[i].offset
            : (u32)(cmd->request_buffer);
        u32 bbuf = virt_to_bus((void *)vbuf);
        u32 count = cmd->use_sg ?
            ((struct scatterlist *)cmd->buffer)[i].length :
            cmd->request_bufflen;

        /*
         * If we have buffers which are not aligned with 16 byte cache
         * lines, then we just hope nothing accesses the other parts of
         * those cache lines while the transfer is in progress.  That would
         * fill the cache, and subsequent reads of the dma data would pick
         * up the wrong thing.
         * XXX We need a bounce buffer to handle that correctly.
         */

        if (((bbuf & 15) || (count & 15)) && (datain || dataout))
        {
            /* Bounce buffer needed */
            if (cmd->use_sg)
                printk ("53c7xx: Non-aligned buffer with use_sg\n");
            else if (datain && dataout)
                printk ("53c7xx: Non-aligned buffer with datain && dataout\n");
            else if (count > 256)
                printk ("53c7xx: Non-aligned transfer > 256 bytes\n");
            else
            {
                    if (datain)
                    {
                        tmp->bounce.len = count;
                        tmp->bounce.addr = vbuf;
                        bbuf = virt_to_bus(tmp->bounce.buf);
                        tmp->bounce.buf[0] = 0xff;
                        tmp->bounce.buf[1] = 0xfe;
                        tmp->bounce.buf[2] = 0xfd;
                        tmp->bounce.buf[3] = 0xfc;
                    }
                    if (dataout)
                    {
                        memcpy ((void *)tmp->bounce.buf, (void *)vbuf, count);
                        bbuf = virt_to_bus(tmp->bounce.buf);
                    }
            }
        }

        if (datain) {
            cache_clear(virt_to_phys((void *)vbuf), count);
            /* CALL other_in, WHEN NOT DATA_IN */  
            cmd_datain[0] = ((DCMD_TYPE_TCI | DCMD_TCI_OP_CALL | 
                DCMD_TCI_IO) << 24) | 
                DBC_TCI_WAIT_FOR_VALID | DBC_TCI_COMPARE_PHASE;
            cmd_datain[1] = virt_to_bus (hostdata->script) + 
                hostdata->E_other_in;
            /* MOVE count, buf, WHEN DATA_IN */
            cmd_datain[2] = ((DCMD_TYPE_BMI | DCMD_BMI_OP_MOVE_I | DCMD_BMI_IO) 
                << 24) | count;
            cmd_datain[3] = bbuf;
#if 0
            print_insn (host, cmd_datain, "dynamic ", 1);
            print_insn (host, cmd_datain + 2, "dynamic ", 1);
#endif
        }
        if (dataout) {
            cache_push(virt_to_phys((void *)vbuf), count);
            /* CALL other_out, WHEN NOT DATA_OUT */
            cmd_dataout[0] = ((DCMD_TYPE_TCI | DCMD_TCI_OP_CALL) << 24) | 
                DBC_TCI_WAIT_FOR_VALID | DBC_TCI_COMPARE_PHASE;
            cmd_dataout[1] = virt_to_bus(hostdata->script) + 
                hostdata->E_other_out;
            /* MOVE count, buf, WHEN DATA+OUT */
            cmd_dataout[2] = ((DCMD_TYPE_BMI | DCMD_BMI_OP_MOVE_I) << 24) 
                | count;
            cmd_dataout[3] = bbuf;
#if 0
            print_insn (host, cmd_dataout, "dynamic ", 1);
            print_insn (host, cmd_dataout + 2, "dynamic ", 1);
#endif
        }
    }

    /*
     * Install JUMP instructions after the data transfer routines to return
     * control to the do_other_transfer routines.
     */
  
    
    if (datain) {
        cmd_datain[0] = ((DCMD_TYPE_TCI | DCMD_TCI_OP_JUMP) << 24) |
            DBC_TCI_TRUE;
        cmd_datain[1] = virt_to_bus(hostdata->script) + 
            hostdata->E_other_transfer;
#if 0
        print_insn (host, cmd_datain, "dynamic jump ", 1);
#endif
        cmd_datain += 2; 
    }
#if 0
    if (datain) {
        cmd_datain[0] = 0x98080000;
        cmd_datain[1] = 0x03ffdeed;
        cmd_datain += 2;
    }
#endif
    if (dataout) {
        cmd_dataout[0] = ((DCMD_TYPE_TCI | DCMD_TCI_OP_JUMP) << 24) |
            DBC_TCI_TRUE;
        cmd_dataout[1] = virt_to_bus(hostdata->script) + 
            hostdata->E_other_transfer;
#if 0
        print_insn (host, cmd_dataout, "dynamic jump ", 1);
#endif
        cmd_dataout += 2;
    }

    return tmp;
}

/*
 * Function : int NCR53c7xx_queue_command (Scsi_Cmnd *cmd,
 *      void (*done)(Scsi_Cmnd *))
 *
 * Purpose :  enqueues a SCSI command
 *
 * Inputs : cmd - SCSI command, done - function called on completion, with
 *      a pointer to the command descriptor.
 *
 * Returns : 0
 *
 * Side effects :
 *      cmd is added to the per instance driver issue_queue, with major
 *      twiddling done to the host specific fields of cmd.  If the
 *      process_issue_queue coroutine isn't running, it is restarted.
 * 
 * NOTE : we use the host_scribble field of the Scsi_Cmnd structure to 
 *      hold our own data, and pervert the ptr field of the SCp field
 *      to create a linked list.
 */

int
NCR53c7xx_queue_command (Scsi_Cmnd *cmd, void (* done)(Scsi_Cmnd *)) {
    struct Scsi_Host *host = cmd->device->host;
    struct NCR53c7x0_hostdata *hostdata = 
        (struct NCR53c7x0_hostdata *) host->hostdata[0];
    unsigned long flags;
    Scsi_Cmnd *tmp;

    cmd->scsi_done = done;
    cmd->host_scribble = NULL;
    cmd->SCp.ptr = NULL;
    cmd->SCp.buffer = NULL;

#ifdef VALID_IDS
    /* Ignore commands on invalid IDs */
    if (!hostdata->valid_ids[cmd->device->id]) {
        printk("scsi%d : ignoring target %d lun %d\n", host->host_no,
            cmd->device->id, cmd->device->lun);
        cmd->result = (DID_BAD_TARGET << 16);
        done(cmd);
        return 0;
    }
#endif

    local_irq_save(flags);
    if ((hostdata->options & (OPTION_DEBUG_INIT_ONLY|OPTION_DEBUG_PROBE_ONLY)) 
        || ((hostdata->options & OPTION_DEBUG_TARGET_LIMIT) &&
            !(hostdata->debug_lun_limit[cmd->device->id] & (1 << cmd->device->lun)))
#ifdef LINUX_1_2
        || cmd->device->id > 7
#else
        || cmd->device->id > host->max_id
#endif
        || cmd->device->id == host->this_id
        || hostdata->state == STATE_DISABLED) {
        printk("scsi%d : disabled or bad target %d lun %d\n", host->host_no,
            cmd->device->id, cmd->device->lun);
        cmd->result = (DID_BAD_TARGET << 16);
        done(cmd);
        local_irq_restore(flags);
        return 0;
    }

    if ((hostdata->options & OPTION_DEBUG_NCOMMANDS_LIMIT) &&
        (hostdata->debug_count_limit == 0)) {
        printk("scsi%d : maximum commands exceeded\n", host->host_no);
        cmd->result = (DID_BAD_TARGET << 16);
        done(cmd);
        local_irq_restore(flags);
        return 0;
    }

    if (hostdata->options & OPTION_DEBUG_READ_ONLY) {
        switch (cmd->cmnd[0]) {
        case WRITE_6:
        case WRITE_10:
            printk("scsi%d : WRITE attempted with NO_WRITE debugging flag set\n",
                host->host_no);
            cmd->result = (DID_BAD_TARGET << 16);
            done(cmd);
            local_irq_restore(flags);
            return 0;
        }
    }

    if ((hostdata->options & OPTION_DEBUG_TARGET_LIMIT) &&
            hostdata->debug_count_limit != -1) 
        --hostdata->debug_count_limit;

    cmd->result = 0xffff;       /* The NCR will overwrite message
                                       and status with valid data */
    cmd->host_scribble = (unsigned char *) tmp = create_cmd (cmd);

    /*
     * REQUEST SENSE commands are inserted at the head of the queue 
     * so that we do not clear the contingent allegiance condition
     * they may be looking at.
     */

    if (!(hostdata->issue_queue) || (cmd->cmnd[0] == REQUEST_SENSE)) {
        cmd->SCp.ptr = (unsigned char *) hostdata->issue_queue;
        hostdata->issue_queue = cmd;
    } else {
        for (tmp = (Scsi_Cmnd *) hostdata->issue_queue; tmp->SCp.ptr; 
                tmp = (Scsi_Cmnd *) tmp->SCp.ptr);
        tmp->SCp.ptr = (unsigned char *) cmd;
    }
    local_irq_restore(flags);
    run_process_issue_queue();
    return 0;
}

/*
 * Function : void to_schedule_list (struct Scsi_Host *host,
 *      struct NCR53c7x0_hostdata * hostdata, Scsi_Cmnd *cmd)
 *
 * Purpose : takes a SCSI command which was just removed from the 
 *      issue queue, and deals with it by inserting it in the first
 *      free slot in the schedule list or by terminating it immediately.
 *
 * Inputs : 
 *      host - SCSI host adapter; hostdata - hostdata structure for 
 *      this adapter; cmd - a pointer to the command; should have 
 *      the host_scribble field initialized to point to a valid 
 *      
 * Side effects : 
 *      cmd is added to the per instance schedule list, with minor 
 *      twiddling done to the host specific fields of cmd.
 *
 */

static __inline__ void
to_schedule_list (struct Scsi_Host *host, struct NCR53c7x0_hostdata *hostdata,
    struct NCR53c7x0_cmd *cmd) {
    NCR53c7x0_local_declare();
    Scsi_Cmnd *tmp = cmd->cmd;
    unsigned long flags;
    /* dsa start is negative, so subtraction is used */
    volatile u32 *ncrcurrent;

    int i;
    NCR53c7x0_local_setup(host);
#if 0
    printk("scsi%d : new dsa is 0x%lx (virt 0x%p)\n", host->host_no, 
        virt_to_bus(hostdata->dsa), hostdata->dsa);
#endif

    local_irq_save(flags);
    
    /* 
     * Work around race condition : if an interrupt fired and we 
     * got disabled forget about this command.
     */

    if (hostdata->state == STATE_DISABLED) {
        printk("scsi%d : driver disabled\n", host->host_no);
        tmp->result = (DID_BAD_TARGET << 16);
        cmd->next = (struct NCR53c7x0_cmd *) hostdata->free;
        hostdata->free = cmd;
        tmp->scsi_done(tmp);
        local_irq_restore(flags);
        return;
    }

    for (i = host->can_queue, ncrcurrent = hostdata->schedule; 
        i > 0  && ncrcurrent[0] != hostdata->NOP_insn;
        --i, ncrcurrent += 2 /* JUMP instructions are two words */);

    if (i > 0) {
        ++hostdata->busy[tmp->device->id][tmp->device->lun];
        cmd->next = hostdata->running_list;
        hostdata->running_list = cmd;

        /* Restore this instruction to a NOP once the command starts */
        cmd->dsa [(hostdata->dsa_jump_dest - hostdata->dsa_start) / 
            sizeof(u32)] = (u32) virt_to_bus ((void *)ncrcurrent);
        /* Replace the current jump operand.  */
        ncrcurrent[1] =
            virt_to_bus ((void *) cmd->dsa) + hostdata->E_dsa_code_begin -
            hostdata->E_dsa_code_template;
        /* Replace the NOP instruction with a JUMP */
        ncrcurrent[0] = ((DCMD_TYPE_TCI|DCMD_TCI_OP_JUMP) << 24) |
            DBC_TCI_TRUE;
    }  else {
        printk ("scsi%d: no free slot\n", host->host_no);
        disable(host);
        tmp->result = (DID_ERROR << 16);
        cmd->next = (struct NCR53c7x0_cmd *) hostdata->free;
        hostdata->free = cmd;
        tmp->scsi_done(tmp);
        local_irq_restore(flags);
        return;
    }

    /* 
     * If the NCR chip is in an idle state, start it running the scheduler
     * immediately.  Otherwise, signal the chip to jump to schedule as 
     * soon as it is idle.
     */

    if (hostdata->idle) {
        hostdata->idle = 0;
        hostdata->state = STATE_RUNNING;
        NCR53c7x0_write32 (DSP_REG,  virt_to_bus ((void *)hostdata->schedule));
        if (hostdata->options & OPTION_DEBUG_TRACE)
            NCR53c7x0_write8 (DCNTL_REG, hostdata->saved_dcntl |
                                DCNTL_SSM | DCNTL_STD);
    } else {
        NCR53c7x0_write8(hostdata->istat, ISTAT_10_SIGP);
    }

    local_irq_restore(flags);
}

/*
 * Function : busyp (struct Scsi_Host *host, struct NCR53c7x0_hostdata 
 *      *hostdata, Scsi_Cmnd *cmd)
 *
 * Purpose : decide if we can pass the given SCSI command on to the 
 *      device in question or not.
 *  
 * Returns : non-zero when we're busy, 0 when we aren't.
 */

static __inline__ int
busyp (struct Scsi_Host *host, struct NCR53c7x0_hostdata *hostdata, 
    Scsi_Cmnd *cmd) {
    /* FIXME : in the future, this needs to accommodate SCSI-II tagged
       queuing, and we may be able to play with fairness here a bit.
     */
    return hostdata->busy[cmd->device->id][cmd->device->lun];
}

/*
 * Function : process_issue_queue (void)
 *
 * Purpose : transfer commands from the issue queue to NCR start queue 
 *      of each NCR53c7/8xx in the system, avoiding kernel stack 
 *      overflows when the scsi_done() function is invoked recursively.
 * 
 * NOTE : process_issue_queue exits with interrupts *disabled*, so the 
 *      caller must reenable them if it desires.
 * 
 * NOTE : process_issue_queue should be called from both 
 *      NCR53c7x0_queue_command() and from the interrupt handler 
 *      after command completion in case NCR53c7x0_queue_command()
 *      isn't invoked again but we've freed up resources that are
 *      needed.
 */

static void 
process_issue_queue (unsigned long flags) {
    Scsi_Cmnd *tmp, *prev;
    struct Scsi_Host *host;
    struct NCR53c7x0_hostdata *hostdata;
    int done;

    /*
     * We run (with interrupts disabled) until we're sure that none of 
     * the host adapters have anything that can be done, at which point 
     * we set process_issue_queue_running to 0 and exit.
     *
     * Interrupts are enabled before doing various other internal 
     * instructions, after we've decided that we need to run through
     * the loop again.
     *
     */

    do {
        local_irq_disable(); /* Freeze request queues */
        done = 1;
        for (host = first_host; host && host->hostt == the_template;
            host = host->next) {
            hostdata = (struct NCR53c7x0_hostdata *) host->hostdata[0];
            local_irq_disable();
            if (hostdata->issue_queue) {
                if (hostdata->state == STATE_DISABLED) {
                    tmp = (Scsi_Cmnd *) hostdata->issue_queue;
                    hostdata->issue_queue = (Scsi_Cmnd *) tmp->SCp.ptr;
                    tmp->result = (DID_BAD_TARGET << 16);
                    if (tmp->host_scribble) {
                        ((struct NCR53c7x0_cmd *)tmp->host_scribble)->next = 
                            hostdata->free;
                        hostdata->free = 
                            (struct NCR53c7x0_cmd *)tmp->host_scribble;
                        tmp->host_scribble = NULL;
                    }
                    tmp->scsi_done (tmp);
                    done = 0;
                } else 
                    for (tmp = (Scsi_Cmnd *) hostdata->issue_queue, 
                        prev = NULL; tmp; prev = tmp, tmp = (Scsi_Cmnd *) 
                        tmp->SCp.ptr) 
                        if (!tmp->host_scribble || 
                            !busyp (host, hostdata, tmp)) {
                                if (prev)
                                    prev->SCp.ptr = tmp->SCp.ptr;
                                else
                                    hostdata->issue_queue = (Scsi_Cmnd *) 
                                        tmp->SCp.ptr;
                            tmp->SCp.ptr = NULL;
                            if (tmp->host_scribble) {
                                if (hostdata->options & OPTION_DEBUG_QUEUES) 
                                    printk ("scsi%d : moving command for target %d lun %d to start list\n",
                                        host->host_no, tmp->device->id, tmp->device->lun);
                

                                to_schedule_list (host, hostdata, 
                                    (struct NCR53c7x0_cmd *)
                                    tmp->host_scribble);
                            } else {
                                if (((tmp->result & 0xff) == 0xff) ||
                                    ((tmp->result & 0xff00) == 0xff00)) {
                                    printk ("scsi%d : danger Will Robinson!\n",
                                        host->host_no);
                                    tmp->result = DID_ERROR << 16;
                                    disable (host);
                                }
                                tmp->scsi_done(tmp);
                            }
                            done = 0;
                        } /* if target/lun is not busy */
            } /* if hostdata->issue_queue */
            if (!done)
                local_irq_restore(flags);
        } /* for host */
    } while (!done);
    process_issue_queue_running = 0;
}

/*
 * Function : static void intr_scsi (struct Scsi_Host *host, 
 *      struct NCR53c7x0_cmd *cmd)
 *
 * Purpose : handle all SCSI interrupts, indicated by the setting 
 *      of the SIP bit in the ISTAT register.
 *
 * Inputs : host, cmd - host and NCR command causing the interrupt, cmd
 *      may be NULL.
 */

static void 
intr_scsi (struct Scsi_Host *host, struct NCR53c7x0_cmd *cmd) {
    NCR53c7x0_local_declare();
    struct NCR53c7x0_hostdata *hostdata = 
        (struct NCR53c7x0_hostdata *) host->hostdata[0];
    unsigned char sstat0_sist0, sist1,          /* Registers */
            fatal;                              /* Did a fatal interrupt 
                                                   occur ? */
   
    NCR53c7x0_local_setup(host);

    fatal = 0;

    sstat0_sist0 = NCR53c7x0_read8(SSTAT0_REG);
    sist1 = 0;

    if (hostdata->options & OPTION_DEBUG_INTR) 
        printk ("scsi%d : SIST0 0x%0x, SIST1 0x%0x\n", host->host_no,
            sstat0_sist0, sist1);

    /* 250ms selection timeout */
    if (sstat0_sist0 & SSTAT0_700_STO) {
        fatal = 1;
        if (hostdata->options & OPTION_DEBUG_INTR) {
            printk ("scsi%d : Selection Timeout\n", host->host_no);
            if (cmd) {
                printk("scsi%d : target %d, lun %d, command ",
                    host->host_no, cmd->cmd->device->id, cmd->cmd->device->lun);
                print_command (cmd->cmd->cmnd);
                printk("scsi%d : dsp = 0x%x (virt 0x%p)\n", host->host_no,
                    NCR53c7x0_read32(DSP_REG),
                    bus_to_virt(NCR53c7x0_read32(DSP_REG)));
            } else {
                printk("scsi%d : no command\n", host->host_no);
            }
        }
/*
 * XXX - question : how do we want to handle the Illegal Instruction
 *      interrupt, which may occur before or after the Selection Timeout
 *      interrupt?
 */

        if (1) {
            hostdata->idle = 1;
            hostdata->expecting_sto = 0;

            if (hostdata->test_running) {
                hostdata->test_running = 0;
                hostdata->test_completed = 3;
            } else if (cmd) {
                abnormal_finished(cmd, DID_BAD_TARGET << 16);
            }
#if 0       
            hostdata->intrs = 0;
#endif
        }
    } 

/*
 * FIXME : in theory, we can also get a UDC when a STO occurs.
 */
    if (sstat0_sist0 & SSTAT0_UDC) {
        fatal = 1;
        if (cmd) {
            printk("scsi%d : target %d lun %d unexpected disconnect\n",
                host->host_no, cmd->cmd->device->id, cmd->cmd->device->lun);
            print_lots (host);
            abnormal_finished(cmd, DID_ERROR << 16);
        } else 
             printk("scsi%d : unexpected disconnect (no command)\n",
                host->host_no);

        hostdata->dsp = (u32 *) hostdata->schedule;
        hostdata->dsp_changed = 1;
    }

    /* SCSI PARITY error */
    if (sstat0_sist0 & SSTAT0_PAR) {
        fatal = 1;
        if (cmd && cmd->cmd) {
            printk("scsi%d : target %d lun %d parity error.\n",
                host->host_no, cmd->cmd->device->id, cmd->cmd->device->lun);
            abnormal_finished (cmd, DID_PARITY << 16); 
        } else
            printk("scsi%d : parity error\n", host->host_no);
        /* Should send message out, parity error */

        /* XXX - Reduce synchronous transfer rate! */