/*

   * NCR 5380 generic driver routines.  These should make it *trivial*

   *	to implement 5380 SCSI drivers under Linux with a non-trantor

   *	architecture.
   *
   *	Note that these routines also work with NR53c400 family chips.
   *
   * Copyright 1993, Drew Eckhardt

   *	Visionary Computing

   *	(Unix and Linux consulting and custom programming)

   *	drew@colorado.edu

   *	+1 (303) 666-5836
   *

   * DISTRIBUTION RELEASE 6.

   *

   * For more information, please consult

   *
   * NCR 5380 Family
   * SCSI Protocol Controller
   * Databook
   *
   * NCR Microelectronics
   * 1635 Aeroplaza Drive
   * Colorado Springs, CO 80916
   * 1+ (719) 578-3400
   * 1+ (800) 334-5454
   */
  
  /*
   * ++roman: To port the 5380 driver to the Atari, I had to do some changes in
   * this file, too:
   *
   *  - Some of the debug statements were incorrect (undefined variables and the
   *    like). I fixed that.
   *
   *  - In information_transfer(), I think a #ifdef was wrong. Looking at the
   *    possible DMA transfer size should also happen for REAL_DMA. I added this
   *    in the #if statement.
   *
   *  - When using real DMA, information_transfer() should return in a DATAOUT
   *    phase after starting the DMA. It has nothing more to do.
   *
   *  - The interrupt service routine should run main after end of DMA, too (not
   *    only after RESELECTION interrupts). Additionally, it should _not_ test
   *    for more interrupts after running main, since a DMA process may have
   *    been started and interrupts are turned on now. The new int could happen
   *    inside the execution of NCR5380_intr(), leading to recursive
   *    calls.
   *
   *  - I've added a function merge_contiguous_buffers() that tries to
   *    merge scatter-gather buffers that are located at contiguous
   *    physical addresses and can be processed with the same DMA setup.
   *    Since most scatter-gather operations work on a page (4K) of
   *    4 buffers (1K), in more than 90% of all cases three interrupts and
   *    DMA setup actions are saved.
   *
   * - I've deleted all the stuff for AUTOPROBE_IRQ, REAL_DMA_POLL, PSEUDO_DMA
   *    and USLEEP, because these were messing up readability and will never be
   *    needed for Atari SCSI.

   *

   * - I've revised the NCR5380_main() calling scheme (relax the 'main_running'
   *   stuff), and 'main' is executed in a bottom half if awoken by an
   *   interrupt.
   *
   * - The code was quite cluttered up by "#if (NDEBUG & NDEBUG_*) printk..."
   *   constructs. In my eyes, this made the source rather unreadable, so I
   *   finally replaced that by the *_PRINTK() macros.
   *
   */
  
  /*

   * Further development / testing that should be done :
   * 1.  Test linked command handling code after Eric is ready with

   *     the high level code.
   */

  #include <scsi/scsi_dbg.h>

  #include <scsi/scsi_transport_spi.h>

  
  #if (NDEBUG & NDEBUG_LISTS)

  #define LIST(x, y)						\
  	do {							\
  		printk("LINE:%d   Adding %p to %p
  ",		\
  		       __LINE__, (void*)(x), (void*)(y));	\
  		if ((x) == (y))					\
  			udelay(5);				\
  	} while (0)
  #define REMOVE(w, x, y, z)					\
  	do {							\
  		printk("LINE:%d   Removing: %p->%p  %p->%p 
  ",	\
  		       __LINE__, (void*)(w), (void*)(x),	\
  		       (void*)(y), (void*)(z));			\
  		if ((x) == (y))					\
  			udelay(5);				\
  	} while (0)

  #else
  #define LIST(x,y)
  #define REMOVE(w,x,y,z)
  #endif
  
  #ifndef notyet
  #undef LINKED
  #endif
  
  /*
   * Design
   * Issues :
   *
   * The other Linux SCSI drivers were written when Linux was Intel PC-only,
   * and specifically for each board rather than each chip.  This makes their
   * adaptation to platforms like the Mac (Some of which use NCR5380's)
   * more difficult than it has to be.
   *
   * Also, many of the SCSI drivers were written before the command queuing

   * routines were implemented, meaning their implementations of queued

   * commands were hacked on rather than designed in from the start.
   *

   * When I designed the Linux SCSI drivers I figured that

   * while having two different SCSI boards in a system might be useful
   * for debugging things, two of the same type wouldn't be used.
   * Well, I was wrong and a number of users have mailed me about running
   * multiple high-performance SCSI boards in a server.
   *

   * Finally, when I get questions from users, I have no idea what

   * revision of my driver they are running.
   *
   * This driver attempts to address these problems :

   * This is a generic 5380 driver.  To use it on a different platform,

   * one simply writes appropriate system specific macros (ie, data

   * transfer - some PC's will use the I/O bus, 68K's must use

   * memory mapped) and drops this file in their 'C' wrapper.
   *

   * As far as command queueing, two queues are maintained for

   * each 5380 in the system - commands that haven't been issued yet,

   * and commands that are currently executing.  This means that an
   * unlimited number of commands may be queued, letting
   * more commands propagate from the higher driver levels giving higher
   * throughput.  Note that both I_T_L and I_T_L_Q nexuses are supported,
   * allowing multiple commands to propagate all the way to a SCSI-II device

   * while a command is already executing.
   *

   * To solve the multiple-boards-in-the-same-system problem,

   * there is a separate instance structure for each instance
   * of a 5380 in the system.  So, multiple NCR5380 drivers will
   * be able to coexist with appropriate changes to the high level

   * SCSI code.

   *
   * A NCR5380_PUBLIC_REVISION macro is provided, with the release

   * number (updated for each public release) printed by the
   * NCR5380_print_options command, which should be called from the

   * wrapper detect function, so that I know what release of the driver
   * users are using.
   *

   * Issues specific to the NCR5380 :

   *

   * When used in a PIO or pseudo-dma mode, the NCR5380 is a braindead
   * piece of hardware that requires you to sit in a loop polling for
   * the REQ signal as long as you are connected.  Some devices are
   * brain dead (ie, many TEXEL CD ROM drives) and won't disconnect

   * while doing long seek operations.

   *

   * The workaround for this is to keep track of devices that have
   * disconnected.  If the device hasn't disconnected, for commands that

   * should disconnect, we do something like

   *
   * while (!REQ is asserted) { sleep for N usecs; poll for M usecs }

   *
   * Some tweaking of N and M needs to be done.  An algorithm based

   * on "time to data" would give the best results as long as short time

   * to datas (ie, on the same track) were considered, however these

   * broken devices are the exception rather than the rule and I'd rather
   * spend my time optimizing for the normal case.
   *
   * Architecture :
   *
   * At the heart of the design is a coroutine, NCR5380_main,
   * which is started when not running by the interrupt handler,
   * timer, and queue command function.  It attempts to establish

   * I_T_L or I_T_L_Q nexuses by removing the commands from the
   * issue queue and calling NCR5380_select() if a nexus
   * is not established.

   *
   * Once a nexus is established, the NCR5380_information_transfer()
   * phase goes through the various phases as instructed by the target.
   * if the target goes into MSG IN and sends a DISCONNECT message,
   * the command structure is placed into the per instance disconnected
   * queue, and NCR5380_main tries to find more work.  If USLEEP
   * was defined, and the target is idle for too long, the system
   * will try to sleep.
   *
   * If a command has disconnected, eventually an interrupt will trigger,
   * calling NCR5380_intr()  which will in turn call NCR5380_reselect
   * to reestablish a nexus.  This will run main if necessary.
   *

   * On command termination, the done function will be called as

   * appropriate.
   *

   * SCSI pointers are maintained in the SCp field of SCSI command

   * structures, being initialized after the command is connected
   * in NCR5380_select, and set as appropriate in NCR5380_information_transfer.
   * Note that in violation of the standard, an implicit SAVE POINTERS operation
   * is done, since some BROKEN disks fail to issue an explicit SAVE POINTERS.
   */
  
  /*
   * Using this file :
   * This file a skeleton Linux SCSI driver for the NCR 5380 series

   * of chips.  To use it, you write an architecture specific functions

   * and macros and include this file in your driver.
   *

   * These macros control options :

   * AUTOSENSE - if defined, REQUEST SENSE will be performed automatically

   *	for commands that return with a CHECK CONDITION status.

   *
   * LINKED - if defined, linked commands are supported.
   *
   * REAL_DMA - if defined, REAL DMA is used during the data transfer phases.
   *
   * SUPPORT_TAGS - if defined, SCSI-2 tagged queuing is used where possible
   *
   * These macros MUST be defined :

   *

   * NCR5380_read(register)  - read from the specified register
   *

   * NCR5380_write(register, value) - write to the specific register

   *
   * Either real DMA *or* pseudo DMA may be implemented

   * REAL functions :

   * NCR5380_REAL_DMA should be defined if real DMA is to be used.

   * Note that the DMA setup functions should return the number of bytes

   *	that they were able to program the controller for.
   *

   * Also note that generic i386/PC versions of these macros are

   *	available as NCR5380_i386_dma_write_setup,
   *	NCR5380_i386_dma_read_setup, and NCR5380_i386_dma_residual.
   *
   * NCR5380_dma_write_setup(instance, src, count) - initialize
   * NCR5380_dma_read_setup(instance, dst, count) - initialize
   * NCR5380_dma_residual(instance); - residual count
   *
   * PSEUDO functions :
   * NCR5380_pwrite(instance, src, count)
   * NCR5380_pread(instance, dst, count);
   *
   * If nothing specific to this implementation needs doing (ie, with external

   * hardware), you must also define
   *

   * NCR5380_queue_command
   * NCR5380_reset
   * NCR5380_abort
   * NCR5380_proc_info
   *

   * to be the global entry points into the specific driver, ie

   * #define NCR5380_queue_command t128_queue_command.
   *
   * If this is not done, the routines will be defined as static functions
   * with the NCR5380* names and the user must provide a globally
   * accessible wrapper function.
   *
   * The generic driver is initialized by calling NCR5380_init(instance),

   * after setting the appropriate host specific fields and ID.  If the

   * driver wishes to autoprobe for an IRQ line, the NCR5380_probe_irq(instance,
   * possible) function may be used.  Before the specific driver initialization
   * code finishes, NCR5380_print_options should be called.
   */
  
  static struct Scsi_Host *first_instance = NULL;

  static struct scsi_host_template *the_template = NULL;

  
  /* Macros ease life... :-) */
  #define	SETUP_HOSTDATA(in)				\
      struct NCR5380_hostdata *hostdata =			\
  	(struct NCR5380_hostdata *)(in)->hostdata
  #define	HOSTDATA(in) ((struct NCR5380_hostdata *)(in)->hostdata)

  #define	NEXT(cmd)		((Scsi_Cmnd *)(cmd)->host_scribble)
  #define	SET_NEXT(cmd,next)	((cmd)->host_scribble = (void *)(next))
  #define	NEXTADDR(cmd)		((Scsi_Cmnd **)&(cmd)->host_scribble)

  
  #define	HOSTNO		instance->host_no
  #define	H_NO(cmd)	(cmd)->device->host->host_no
  
  #ifdef SUPPORT_TAGS
  
  /*
   * Functions for handling tagged queuing
   * =====================================
   *
   * ++roman (01/96): Now I've implemented SCSI-2 tagged queuing. Some notes:
   *
   * Using consecutive numbers for the tags is no good idea in my eyes. There
   * could be wrong re-usings if the counter (8 bit!) wraps and some early
   * command has been preempted for a long time. My solution: a bitfield for
   * remembering used tags.
   *
   * There's also the problem that each target has a certain queue size, but we
   * cannot know it in advance :-( We just see a QUEUE_FULL status being
   * returned. So, in this case, the driver internal queue size assumption is
   * reduced to the number of active tags if QUEUE_FULL is returned by the
   * target. The command is returned to the mid-level, but with status changed
   * to BUSY, since --as I've seen-- the mid-level can't handle QUEUE_FULL
   * correctly.
   *
   * We're also not allowed running tagged commands as long as an untagged
   * command is active. And REQUEST SENSE commands after a contingent allegiance
   * condition _must_ be untagged. To keep track whether an untagged command has
   * been issued, the host->busy array is still employed, as it is without
   * support for tagged queuing.
   *
   * One could suspect that there are possible race conditions between
   * is_lun_busy(), cmd_get_tag() and cmd_free_tag(). But I think this isn't the
   * case: is_lun_busy() and cmd_get_tag() are both called from NCR5380_main(),
   * which already guaranteed to be running at most once. It is also the only
   * place where tags/LUNs are allocated. So no other allocation can slip
   * between that pair, there could only happen a reselection, which can free a
   * tag, but that doesn't hurt. Only the sequence in cmd_free_tag() becomes
   * important: the tag bit must be cleared before 'nr_allocated' is decreased.
   */
  
  /* -1 for TAG_NONE is not possible with unsigned char cmd->tag */
  #undef TAG_NONE
  #define TAG_NONE 0xff
  
  typedef struct {

  	DECLARE_BITMAP(allocated, MAX_TAGS);
  	int nr_allocated;
  	int queue_size;

  } TAG_ALLOC;

  static TAG_ALLOC TagAlloc[8][8];	/* 8 targets and 8 LUNs */

  static void __init init_tags(void)

  {

  	int target, lun;
  	TAG_ALLOC *ta;
  
  	if (!setup_use_tagged_queuing)
  		return;
  
  	for (target = 0; target < 8; ++target) {
  		for (lun = 0; lun < 8; ++lun) {
  			ta = &TagAlloc[target][lun];
  			bitmap_zero(ta->allocated, MAX_TAGS);
  			ta->nr_allocated = 0;
  			/* At the beginning, assume the maximum queue size we could
  			 * support (MAX_TAGS). This value will be decreased if the target
  			 * returns QUEUE_FULL status.
  			 */
  			ta->queue_size = MAX_TAGS;
  		}

  	}

  }
  
  
  /* Check if we can issue a command to this LUN: First see if the LUN is marked
   * busy by an untagged command. If the command should use tagged queuing, also
   * check that there is a free tag and the target's queue won't overflow. This
   * function should be called with interrupts disabled to avoid race
   * conditions.

   */

  static int is_lun_busy(Scsi_Cmnd *cmd, int should_be_tagged)

  {

  	SETUP_HOSTDATA(cmd->device->host);
  
  	if (hostdata->busy[cmd->device->id] & (1 << cmd->device->lun))
  		return 1;
  	if (!should_be_tagged ||
  	    !setup_use_tagged_queuing || !cmd->device->tagged_supported)
  		return 0;
  	if (TagAlloc[cmd->device->id][cmd->device->lun].nr_allocated >=
  	    TagAlloc[cmd->device->id][cmd->device->lun].queue_size) {
  		TAG_PRINTK("scsi%d: target %d lun %d: no free tags
  ",
  			   H_NO(cmd), cmd->device->id, cmd->device->lun);
  		return 1;
  	}
  	return 0;

  }
  
  
  /* Allocate a tag for a command (there are no checks anymore, check_lun_busy()
   * must be called before!), or reserve the LUN in 'busy' if the command is
   * untagged.
   */

  static void cmd_get_tag(Scsi_Cmnd *cmd, int should_be_tagged)

  {

  	SETUP_HOSTDATA(cmd->device->host);
  
  	/* If we or the target don't support tagged queuing, allocate the LUN for
  	 * an untagged command.
  	 */
  	if (!should_be_tagged ||
  	    !setup_use_tagged_queuing || !cmd->device->tagged_supported) {
  		cmd->tag = TAG_NONE;
  		hostdata->busy[cmd->device->id] |= (1 << cmd->device->lun);
  		TAG_PRINTK("scsi%d: target %d lun %d now allocated by untagged "
  			   "command
  ", H_NO(cmd), cmd->device->id, cmd->device->lun);
  	} else {
  		TAG_ALLOC *ta = &TagAlloc[cmd->device->id][cmd->device->lun];
  
  		cmd->tag = find_first_zero_bit(ta->allocated, MAX_TAGS);
  		set_bit(cmd->tag, ta->allocated);
  		ta->nr_allocated++;
  		TAG_PRINTK("scsi%d: using tag %d for target %d lun %d "
  			   "(now %d tags in use)
  ",
  			   H_NO(cmd), cmd->tag, cmd->device->id,
  			   cmd->device->lun, ta->nr_allocated);
  	}

  }
  
  
  /* Mark the tag of command 'cmd' as free, or in case of an untagged command,
   * unlock the LUN.
   */

  static void cmd_free_tag(Scsi_Cmnd *cmd)

  {

  	SETUP_HOSTDATA(cmd->device->host);
  
  	if (cmd->tag == TAG_NONE) {
  		hostdata->busy[cmd->device->id] &= ~(1 << cmd->device->lun);
  		TAG_PRINTK("scsi%d: target %d lun %d untagged cmd finished
  ",
  			   H_NO(cmd), cmd->device->id, cmd->device->lun);
  	} else if (cmd->tag >= MAX_TAGS) {
  		printk(KERN_NOTICE "scsi%d: trying to free bad tag %d!
  ",
  		       H_NO(cmd), cmd->tag);
  	} else {
  		TAG_ALLOC *ta = &TagAlloc[cmd->device->id][cmd->device->lun];
  		clear_bit(cmd->tag, ta->allocated);
  		ta->nr_allocated--;
  		TAG_PRINTK("scsi%d: freed tag %d for target %d lun %d
  ",
  			   H_NO(cmd), cmd->tag, cmd->device->id, cmd->device->lun);
  	}

  }

  static void free_all_tags(void)

  {

  	int target, lun;
  	TAG_ALLOC *ta;
  
  	if (!setup_use_tagged_queuing)
  		return;
  
  	for (target = 0; target < 8; ++target) {
  		for (lun = 0; lun < 8; ++lun) {
  			ta = &TagAlloc[target][lun];
  			bitmap_zero(ta->allocated, MAX_TAGS);
  			ta->nr_allocated = 0;
  		}

  	}

  }
  
  #endif /* SUPPORT_TAGS */
  
  
  /*
   * Function: void merge_contiguous_buffers( Scsi_Cmnd *cmd )
   *
   * Purpose: Try to merge several scatter-gather requests into one DMA
   *    transfer. This is possible if the scatter buffers lie on
   *    physical contiguous addresses.
   *
   * Parameters: Scsi_Cmnd *cmd
   *    The command to work on. The first scatter buffer's data are

   *    assumed to be already transferred into ptr/this_residual.

   */

  static void merge_contiguous_buffers(Scsi_Cmnd *cmd)

  {

  	unsigned long endaddr;

  #if (NDEBUG & NDEBUG_MERGING)

  	unsigned long oldlen = cmd->SCp.this_residual;
  	int cnt = 1;

  #endif

  	for (endaddr = virt_to_phys(cmd->SCp.ptr + cmd->SCp.this_residual - 1) + 1;
  	     cmd->SCp.buffers_residual &&

  	     virt_to_phys(sg_virt(&cmd->SCp.buffer[1])) == endaddr;) {

  		MER_PRINTK("VTOP(%p) == %08lx -> merging
  ",

  			   page_address(sg_page(&cmd->SCp.buffer[1])), endaddr);

  #if (NDEBUG & NDEBUG_MERGING)

  		++cnt;

  #endif

  		++cmd->SCp.buffer;
  		--cmd->SCp.buffers_residual;
  		cmd->SCp.this_residual += cmd->SCp.buffer->length;
  		endaddr += cmd->SCp.buffer->length;
  	}

  #if (NDEBUG & NDEBUG_MERGING)

  	if (oldlen != cmd->SCp.this_residual)
  		MER_PRINTK("merged %d buffers from %p, new length %08x
  ",
  			   cnt, cmd->SCp.ptr, cmd->SCp.this_residual);

  #endif
  }
  
  /*
   * Function : void initialize_SCp(Scsi_Cmnd *cmd)
   *

   * Purpose : initialize the saved data pointers for cmd to point to the

   *	start of the buffer.
   *
   * Inputs : cmd - Scsi_Cmnd structure to have pointers reset.
   */

  static inline void initialize_SCp(Scsi_Cmnd *cmd)

  {

  	/*
  	 * Initialize the Scsi Pointer field so that all of the commands in the
  	 * various queues are valid.

  	 */

  	if (scsi_bufflen(cmd)) {
  		cmd->SCp.buffer = scsi_sglist(cmd);
  		cmd->SCp.buffers_residual = scsi_sg_count(cmd) - 1;

  		cmd->SCp.ptr = sg_virt(cmd->SCp.buffer);

  		cmd->SCp.this_residual = cmd->SCp.buffer->length;
  		/* ++roman: Try to merge some scatter-buffers if they are at
  		 * contiguous physical addresses.
  		 */
  		merge_contiguous_buffers(cmd);
  	} else {
  		cmd->SCp.buffer = NULL;
  		cmd->SCp.buffers_residual = 0;

  		cmd->SCp.ptr = NULL;
  		cmd->SCp.this_residual = 0;

  	}

  }

  #include <linux/delay.h>
  
  #if NDEBUG
  static struct {

  	unsigned char mask;
  	const char *name;
  } signals[] = {
  	{ SR_DBP, "PARITY"}, { SR_RST, "RST" }, { SR_BSY, "BSY" },
  	{ SR_REQ, "REQ" }, { SR_MSG, "MSG" }, { SR_CD,  "CD" }, { SR_IO, "IO" },
  	{ SR_SEL, "SEL" }, {0, NULL}
  }, basrs[] = {
  	{BASR_ATN, "ATN"}, {BASR_ACK, "ACK"}, {0, NULL}
  }, icrs[] = {
  	{ICR_ASSERT_RST, "ASSERT RST"},{ICR_ASSERT_ACK, "ASSERT ACK"},
  	{ICR_ASSERT_BSY, "ASSERT BSY"}, {ICR_ASSERT_SEL, "ASSERT SEL"},
  	{ICR_ASSERT_ATN, "ASSERT ATN"}, {ICR_ASSERT_DATA, "ASSERT DATA"},
  	{0, NULL}
  }, mrs[] = {
  	{MR_BLOCK_DMA_MODE, "MODE BLOCK DMA"}, {MR_TARGET, "MODE TARGET"},
  	{MR_ENABLE_PAR_CHECK, "MODE PARITY CHECK"}, {MR_ENABLE_PAR_INTR,
  	"MODE PARITY INTR"}, {MR_ENABLE_EOP_INTR,"MODE EOP INTR"},
  	{MR_MONITOR_BSY, "MODE MONITOR BSY"},
  	{MR_DMA_MODE, "MODE DMA"}, {MR_ARBITRATE, "MODE ARBITRATION"},
  	{0, NULL}
  };

  
  /*
   * Function : void NCR5380_print(struct Scsi_Host *instance)
   *
   * Purpose : print the SCSI bus signals for debugging purposes
   *
   * Input : instance - which NCR5380
   */

  static void NCR5380_print(struct Scsi_Host *instance)
  {
  	unsigned char status, data, basr, mr, icr, i;
  	unsigned long flags;
  
  	local_irq_save(flags);
  	data = NCR5380_read(CURRENT_SCSI_DATA_REG);
  	status = NCR5380_read(STATUS_REG);
  	mr = NCR5380_read(MODE_REG);
  	icr = NCR5380_read(INITIATOR_COMMAND_REG);
  	basr = NCR5380_read(BUS_AND_STATUS_REG);
  	local_irq_restore(flags);
  	printk("STATUS_REG: %02x ", status);
  	for (i = 0; signals[i].mask; ++i)
  		if (status & signals[i].mask)
  			printk(",%s", signals[i].name);
  	printk("
  BASR: %02x ", basr);
  	for (i = 0; basrs[i].mask; ++i)
  		if (basr & basrs[i].mask)
  			printk(",%s", basrs[i].name);
  	printk("
  ICR: %02x ", icr);
  	for (i = 0; icrs[i].mask; ++i)
  		if (icr & icrs[i].mask)
  			printk(",%s", icrs[i].name);
  	printk("
  MODE: %02x ", mr);
  	for (i = 0; mrs[i].mask; ++i)
  		if (mr & mrs[i].mask)
  			printk(",%s", mrs[i].name);
  	printk("
  ");

  }
  
  static struct {

  	unsigned char value;
  	const char *name;

  } phases[] = {

  	{PHASE_DATAOUT, "DATAOUT"}, {PHASE_DATAIN, "DATAIN"}, {PHASE_CMDOUT, "CMDOUT"},
  	{PHASE_STATIN, "STATIN"}, {PHASE_MSGOUT, "MSGOUT"}, {PHASE_MSGIN, "MSGIN"},
  	{PHASE_UNKNOWN, "UNKNOWN"}
  };

  /*

   * Function : void NCR5380_print_phase(struct Scsi_Host *instance)
   *
   * Purpose : print the current SCSI phase for debugging purposes
   *
   * Input : instance - which NCR5380
   */
  
  static void NCR5380_print_phase(struct Scsi_Host *instance)
  {

  	unsigned char status;
  	int i;
  
  	status = NCR5380_read(STATUS_REG);
  	if (!(status & SR_REQ))
  		printk(KERN_DEBUG "scsi%d: REQ not asserted, phase unknown.
  ", HOSTNO);
  	else {
  		for (i = 0; (phases[i].value != PHASE_UNKNOWN) &&
  		     (phases[i].value != (status & PHASE_MASK)); ++i)
  			;
  		printk(KERN_DEBUG "scsi%d: phase %s
  ", HOSTNO, phases[i].name);
  	}

  }
  
  #else /* !NDEBUG */
  
  /* dummies... */

  static inline void NCR5380_print(struct Scsi_Host *instance)
  {
  };
  static inline void NCR5380_print_phase(struct Scsi_Host *instance)
  {
  };

  
  #endif
  
  /*
   * ++roman: New scheme of calling NCR5380_main()

   *

   * If we're not in an interrupt, we can call our main directly, it cannot be
   * already running. Else, we queue it on a task queue, if not 'main_running'
   * tells us that a lower level is already executing it. This way,
   * 'main_running' needs not be protected in a special way.
   *
   * queue_main() is a utility function for putting our main onto the task
   * queue, if main_running is false. It should be called only from a
   * interrupt or bottom half.
   */

  #include <linux/gfp.h>

  #include <linux/workqueue.h>
  #include <linux/interrupt.h>

  static volatile int main_running;

  static DECLARE_WORK(NCR5380_tqueue, NCR5380_main);

  static inline void queue_main(void)

  {

  	if (!main_running) {
  		/* If in interrupt and NCR5380_main() not already running,
  		   queue it on the 'immediate' task queue, to be processed
  		   immediately after the current interrupt processing has
  		   finished. */
  		schedule_work(&NCR5380_tqueue);
  	}
  	/* else: nothing to do: the running NCR5380_main() will pick up
  	   any newly queued command. */

  }

  static inline void NCR5380_all_init(void)

  {

  	static int done = 0;
  	if (!done) {
  		INI_PRINTK("scsi : NCR5380_all_init()
  ");
  		done = 1;
  	}

  }

  /*
   * Function : void NCR58380_print_options (struct Scsi_Host *instance)
   *
   * Purpose : called by probe code indicating the NCR5380 driver
   *	     options that were selected.
   *
   * Inputs : instance, pointer to this instance.  Unused.
   */

  static void __init NCR5380_print_options(struct Scsi_Host *instance)

  {

  	printk(" generic options"
  #ifdef AUTOSENSE
  	       " AUTOSENSE"

  #endif
  #ifdef REAL_DMA

  	       " REAL DMA"

  #endif
  #ifdef PARITY

  	       " PARITY"

  #endif
  #ifdef SUPPORT_TAGS

  	       " SCSI-2 TAGGED QUEUING"

  #endif

  	       );
  	printk(" generic release=%d", NCR5380_PUBLIC_RELEASE);

  }
  
  /*
   * Function : void NCR5380_print_status (struct Scsi_Host *instance)
   *
   * Purpose : print commands in the various queues, called from
   *	NCR5380_abort and NCR5380_debug to aid debugging.
   *

   * Inputs : instance, pointer to this instance.

   */

  static void NCR5380_print_status(struct Scsi_Host *instance)

  {

  	char *pr_bfr;
  	char *start;
  	int len;
  
  	NCR_PRINT(NDEBUG_ANY);
  	NCR_PRINT_PHASE(NDEBUG_ANY);
  
  	pr_bfr = (char *)__get_free_page(GFP_ATOMIC);
  	if (!pr_bfr) {
  		printk("NCR5380_print_status: no memory for print buffer
  ");
  		return;
  	}
  	len = NCR5380_proc_info(instance, pr_bfr, &start, 0, PAGE_SIZE, 0);
  	pr_bfr[len] = 0;
  	printk("
  %s
  ", pr_bfr);
  	free_page((unsigned long)pr_bfr);

  }
  
  
  /******************************************/
  /*
   * /proc/scsi/[dtc pas16 t128 generic]/[0-ASC_NUM_BOARD_SUPPORTED]
   *
   * *buffer: I/O buffer
   * **start: if inout == FALSE pointer into buffer where user read should start
   * offset: current offset
   * length: length of buffer
   * hostno: Scsi_Host host_no
   * inout: TRUE - user is writing; FALSE - user is reading
   *
   * Return the number of bytes read from or written
  */
  
  #undef SPRINTF

  #define SPRINTF(fmt,args...)							\
  	do {									\
  		if (pos + strlen(fmt) + 20 /* slop */ < buffer + length)	\
  			pos += sprintf(pos, fmt , ## args);			\
  	} while(0)
  static char *lprint_Scsi_Cmnd(Scsi_Cmnd *cmd, char *pos, char *buffer, int length);
  
  static int NCR5380_proc_info(struct Scsi_Host *instance, char *buffer,
  			     char **start, off_t offset, int length, int inout)

  {

  	char *pos = buffer;
  	struct NCR5380_hostdata *hostdata;
  	Scsi_Cmnd *ptr;
  	unsigned long flags;
  	off_t begin = 0;
  #define check_offset()					\
  	do {						\
  		if (pos - buffer < offset - begin) {	\
  			begin += pos - buffer;		\
  			pos = buffer;			\
  		}					\
  	} while (0)
  
  	hostdata = (struct NCR5380_hostdata *)instance->hostdata;
  
  	if (inout)			/* Has data been written to the file ? */
  		return -ENOSYS;		/* Currently this is a no-op */
  	SPRINTF("NCR5380 core release=%d.
  ", NCR5380_PUBLIC_RELEASE);
  	check_offset();
  	local_irq_save(flags);
  	SPRINTF("NCR5380: coroutine is%s running.
  ",
  		main_running ? "" : "n't");

  	check_offset();

  	if (!hostdata->connected)
  		SPRINTF("scsi%d: no currently connected command
  ", HOSTNO);
  	else
  		pos = lprint_Scsi_Cmnd((Scsi_Cmnd *) hostdata->connected,
  				       pos, buffer, length);
  	SPRINTF("scsi%d: issue_queue
  ", HOSTNO);
  	check_offset();
  	for (ptr = (Scsi_Cmnd *)hostdata->issue_queue; ptr; ptr = NEXT(ptr)) {
  		pos = lprint_Scsi_Cmnd(ptr, pos, buffer, length);
  		check_offset();
  	}

  	SPRINTF("scsi%d: disconnected_queue
  ", HOSTNO);

  	check_offset();

  	for (ptr = (Scsi_Cmnd *) hostdata->disconnected_queue; ptr;
  	     ptr = NEXT(ptr)) {
  		pos = lprint_Scsi_Cmnd(ptr, pos, buffer, length);
  		check_offset();
  	}

  	local_irq_restore(flags);
  	*start = buffer + (offset - begin);
  	if (pos - buffer < offset - begin)
  		return 0;
  	else if (pos - buffer - (offset - begin) < length)
  		return pos - buffer - (offset - begin);
  	return length;

  }

  static char *lprint_Scsi_Cmnd(Scsi_Cmnd *cmd, char *pos, char *buffer, int length)

  {

  	int i, s;
  	unsigned char *command;
  	SPRINTF("scsi%d: destination target %d, lun %d
  ",
  		H_NO(cmd), cmd->device->id, cmd->device->lun);
  	SPRINTF("        command = ");
  	command = cmd->cmnd;
  	SPRINTF("%2d (0x%02x)", command[0], command[0]);
  	for (i = 1, s = COMMAND_SIZE(command[0]); i < s; ++i)
  		SPRINTF(" %02x", command[i]);
  	SPRINTF("
  ");
  	return pos;

  }

  /*

   * Function : void NCR5380_init (struct Scsi_Host *instance)
   *
   * Purpose : initializes *instance and corresponding 5380 chip.
   *

   * Inputs : instance - instantiation of the 5380 driver.

   *
   * Notes : I assume that the host, hostno, and id bits have been

   *	set correctly.  I don't care about the irq and other fields.
   *

   */

  static int __init NCR5380_init(struct Scsi_Host *instance, int flags)

  {

  	int i;
  	SETUP_HOSTDATA(instance);
  
  	NCR5380_all_init();
  
  	hostdata->aborted = 0;
  	hostdata->id_mask = 1 << instance->this_id;
  	hostdata->id_higher_mask = 0;
  	for (i = hostdata->id_mask; i <= 0x80; i <<= 1)
  		if (i > hostdata->id_mask)
  			hostdata->id_higher_mask |= i;
  	for (i = 0; i < 8; ++i)
  		hostdata->busy[i] = 0;

  #ifdef SUPPORT_TAGS

  	init_tags();

  #endif
  #if defined (REAL_DMA)

  	hostdata->dma_len = 0;

  #endif

  	hostdata->targets_present = 0;
  	hostdata->connected = NULL;
  	hostdata->issue_queue = NULL;
  	hostdata->disconnected_queue = NULL;
  	hostdata->flags = FLAG_CHECK_LAST_BYTE_SENT;
  
  	if (!the_template) {
  		the_template = instance->hostt;
  		first_instance = instance;
  	}

  
  #ifndef AUTOSENSE

  	if ((instance->cmd_per_lun > 1) || (instance->can_queue > 1))
  		printk("scsi%d: WARNING : support for multiple outstanding commands enabled
  "
  		       "        without AUTOSENSE option, contingent allegiance conditions may
  "
  		       "        be incorrectly cleared.
  ", HOSTNO);

  #endif /* def AUTOSENSE */

  	NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
  	NCR5380_write(MODE_REG, MR_BASE);
  	NCR5380_write(TARGET_COMMAND_REG, 0);
  	NCR5380_write(SELECT_ENABLE_REG, 0);

  	return 0;

  }

  static void NCR5380_exit(struct Scsi_Host *instance)
  {
  	/* Empty, as we didn't schedule any delayed work */
  }

  /*

   * Function : int NCR5380_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 issue_queue, with minor
   *	twiddling done to the host specific fields of cmd.  If the

   *	main coroutine is not running, it is restarted.
   *
   */

  static int NCR5380_queue_command_lck(Scsi_Cmnd *cmd, void (*done)(Scsi_Cmnd *))

  {

  	SETUP_HOSTDATA(cmd->device->host);
  	Scsi_Cmnd *tmp;

  	unsigned long flags;

  
  #if (NDEBUG & NDEBUG_NO_WRITE)

  	switch (cmd->cmnd[0]) {
  	case WRITE_6:
  	case WRITE_10:
  		printk(KERN_NOTICE "scsi%d: WRITE attempted with NO_WRITE debugging flag set
  ",
  		       H_NO(cmd));
  		cmd->result = (DID_ERROR << 16);
  		done(cmd);
  		return 0;
  	}

  #endif /* (NDEBUG & NDEBUG_NO_WRITE) */

  #ifdef NCR5380_STATS
  # if 0

  	if (!hostdata->connected && !hostdata->issue_queue &&
  	    !hostdata->disconnected_queue) {
  		hostdata->timebase = jiffies;
  	}

  # endif
  # ifdef NCR5380_STAT_LIMIT

  	if (scsi_bufflen(cmd) > NCR5380_STAT_LIMIT)

  # endif

  		switch (cmd->cmnd[0]) {
  		case WRITE:
  		case WRITE_6:
  		case WRITE_10:
  			hostdata->time_write[cmd->device->id] -= (jiffies - hostdata->timebase);

  			hostdata->bytes_write[cmd->device->id] += scsi_bufflen(cmd);

  			hostdata->pendingw++;
  			break;
  		case READ:
  		case READ_6:
  		case READ_10:
  			hostdata->time_read[cmd->device->id] -= (jiffies - hostdata->timebase);

  			hostdata->bytes_read[cmd->device->id] += scsi_bufflen(cmd);

  			hostdata->pendingr++;
  			break;
  		}

  #endif

  	/*
  	 * We use the host_scribble field as a pointer to the next command
  	 * in a queue
  	 */

  	SET_NEXT(cmd, NULL);

  	cmd->scsi_done = done;
  
  	cmd->result = 0;
  
  	/*
  	 * Insert the cmd into the issue queue. Note that REQUEST SENSE
  	 * commands are added to the head of the queue since any command will
  	 * clear the contingent allegiance condition that exists and the
  	 * sense data is only guaranteed to be valid while the condition exists.
  	 */
  
  	local_irq_save(flags);
  	/* ++guenther: now that the issue queue is being set up, we can lock ST-DMA.
  	 * Otherwise a running NCR5380_main may steal the lock.
  	 * Lock before actually inserting due to fairness reasons explained in
  	 * atari_scsi.c. If we insert first, then it's impossible for this driver
  	 * to release the lock.
  	 * Stop timer for this command while waiting for the lock, or timeouts
  	 * may happen (and they really do), and it's no good if the command doesn't
  	 * appear in any of the queues.
  	 * ++roman: Just disabling the NCR interrupt isn't sufficient here,
  	 * because also a timer int can trigger an abort or reset, which would
  	 * alter queues and touch the lock.
  	 */
  	if (!IS_A_TT()) {

  		/* perhaps stop command timer here */

  		falcon_get_lock();

  		/* perhaps restart command timer here */

  	}
  	if (!(hostdata->issue_queue) || (cmd->cmnd[0] == REQUEST_SENSE)) {
  		LIST(cmd, hostdata->issue_queue);

  		SET_NEXT(cmd, hostdata->issue_queue);

  		hostdata->issue_queue = cmd;
  	} else {
  		for (tmp = (Scsi_Cmnd *)hostdata->issue_queue;
  		     NEXT(tmp); tmp = NEXT(tmp))
  			;
  		LIST(cmd, tmp);

  		SET_NEXT(tmp, cmd);

  	}
  	local_irq_restore(flags);
  
  	QU_PRINTK("scsi%d: command added to %s of queue
  ", H_NO(cmd),
  		  (cmd->cmnd[0] == REQUEST_SENSE) ? "head" : "tail");
  
  	/* If queue_command() is called from an interrupt (real one or bottom
  	 * half), we let queue_main() do the job of taking care about main. If it
  	 * is already running, this is a no-op, else main will be queued.
  	 *
  	 * If we're not in an interrupt, we can call NCR5380_main()
  	 * unconditionally, because it cannot be already running.
  	 */
  	if (in_interrupt() || ((flags >> 8) & 7) >= 6)
  		queue_main();
  	else
  		NCR5380_main(NULL);
  	return 0;

  }

  static DEF_SCSI_QCMD(NCR5380_queue_command)

  /*

   * Function : NCR5380_main (void)

   *

   * Purpose : NCR5380_main is a coroutine that runs as long as more work can
   *	be done on the NCR5380 host adapters in a system.  Both
   *	NCR5380_queue_command() and NCR5380_intr() will try to start it

   *	in case it is not running.

   *
   * NOTE : NCR5380_main exits with interrupts *disabled*, the caller should

   *  reenable them.  This prevents reentrancy and kernel stack overflow.

   */

  static void NCR5380_main(struct work_struct *work)

  {

  	Scsi_Cmnd *tmp, *prev;
  	struct Scsi_Host *instance = first_instance;
  	struct NCR5380_hostdata *hostdata = HOSTDATA(instance);
  	int done;
  	unsigned long flags;
  
  	/*
  	 * 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 main_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.
  	 *
  	 * this should prevent any race conditions.
  	 *
  	 * ++roman: Just disabling the NCR interrupt isn't sufficient here,
  	 * because also a timer int can trigger an abort or reset, which can
  	 * alter queues and touch the Falcon lock.
  	 */
  
  	/* Tell int handlers main() is now already executing.  Note that
  	   no races are possible here. If an int comes in before
  	   'main_running' is set here, and queues/executes main via the
  	   task queue, it doesn't do any harm, just this instance of main
  	   won't find any work left to do. */
  	if (main_running)
  		return;
  	main_running = 1;
  
  	local_save_flags(flags);
  	do {
  		local_irq_disable();	/* Freeze request queues */
  		done = 1;
  
  		if (!hostdata->connected) {
  			MAIN_PRINTK("scsi%d: not connected
  ", HOSTNO);
  			/*
  			 * Search through the issue_queue for a command destined
  			 * for a target that's not busy.
  			 */

  #if (NDEBUG & NDEBUG_LISTS)

  			for (tmp = (Scsi_Cmnd *) hostdata->issue_queue, prev = NULL;
  			     tmp && (tmp != prev); prev = tmp, tmp = NEXT(tmp))
  				;
  			/*printk("%p  ", tmp);*/
  			if ((tmp == prev) && tmp)
  				printk(" LOOP
  ");
  			/* else printk("
  "); */

  #endif

  			for (tmp = (Scsi_Cmnd *) hostdata->issue_queue,
  			     prev = NULL; tmp; prev = tmp, tmp = NEXT(tmp)) {

  
  #if (NDEBUG & NDEBUG_LISTS)

  				if (prev != tmp)
  					printk("MAIN tmp=%p   target=%d   busy=%d lun=%d
  ",
  					       tmp, tmp->device->id, hostdata->busy[tmp->device->id],
  					       tmp->device->lun);

  #endif

  				/*  When we find one, remove it from the issue queue. */
  				/* ++guenther: possible race with Falcon locking */
  				if (

  #ifdef SUPPORT_TAGS

  				    !is_lun_busy( tmp, tmp->cmnd[0] != REQUEST_SENSE)

  #else

  				    !(hostdata->busy[tmp->device->id] & (1 << tmp->device->lun))

  #endif

  				    ) {
  					/* ++guenther: just to be sure, this must be atomic */
  					local_irq_disable();
  					if (prev) {
  						REMOVE(prev, NEXT(prev), tmp, NEXT(tmp));

  						SET_NEXT(prev, NEXT(tmp));

  					} else {
  						REMOVE(-1, hostdata->issue_queue, tmp, NEXT(tmp));
  						hostdata->issue_queue = NEXT(tmp);
  					}

  					SET_NEXT(tmp, NULL);

  					falcon_dont_release++;
  
  					/* reenable interrupts after finding one */
  					local_irq_restore(flags);
  
  					/*
  					 * Attempt to establish an I_T_L nexus here.
  					 * On success, instance->hostdata->connected is set.
  					 * On failure, we must add the command back to the
  					 *   issue queue so we can keep trying.
  					 */
  					MAIN_PRINTK("scsi%d: main(): command for target %d "
  						    "lun %d removed from issue_queue
  ",
  						    HOSTNO, tmp->device->id, tmp->device->lun);
  					/*
  					 * REQUEST SENSE commands are issued without tagged
  					 * queueing, even on SCSI-II devices because the
  					 * contingent allegiance condition exists for the
  					 * entire unit.
  					 */
  					/* ++roman: ...and the standard also requires that
  					 * REQUEST SENSE command are untagged.
  					 */

  #ifdef SUPPORT_TAGS

  					cmd_get_tag(tmp, tmp->cmnd[0] != REQUEST_SENSE);

  #endif

  					if (!NCR5380_select(instance, tmp,
  					    (tmp->cmnd[0] == REQUEST_SENSE) ? TAG_NONE :
  					    TAG_NEXT)) {
  						falcon_dont_release--;
  						/* release if target did not response! */
  						falcon_release_lock_if_possible(hostdata);
  						break;
  					} else {
  						local_irq_disable();
  						LIST(tmp, hostdata->issue_queue);

  						SET_NEXT(tmp, hostdata->issue_queue);

  						hostdata->issue_queue = tmp;

  #ifdef SUPPORT_TAGS

  						cmd_free_tag(tmp);

  #endif

  						falcon_dont_release--;
  						local_irq_restore(flags);
  						MAIN_PRINTK("scsi%d: main(): select() failed, "
  							    "returned to issue_queue
  ", HOSTNO);
  						if (hostdata->connected)
  							break;
  					}
  				} /* if target/lun/target queue is not busy */
  			} /* for issue_queue */
  		} /* if (!hostdata->connected) */
  
  		if (hostdata->connected

  #ifdef REAL_DMA

  		    && !hostdata->dma_len

  #endif

  		    ) {
  			local_irq_restore(flags);
  			MAIN_PRINTK("scsi%d: main: performing information transfer
  ",
  				    HOSTNO);
  			NCR5380_information_transfer(instance);
  			MAIN_PRINTK("scsi%d: main: done set false
  ", HOSTNO);
  			done = 0;
  		}
  	} while (!done);

  	/* Better allow ints _after_ 'main_running' has been cleared, else
  	   an interrupt could believe we'll pick up the work it left for
  	   us, but we won't see it anymore here... */
  	main_running = 0;
  	local_irq_restore(flags);

  }
  
  
  #ifdef REAL_DMA
  /*
   * Function : void NCR5380_dma_complete (struct Scsi_Host *instance)
   *
   * Purpose : Called by interrupt handler when DMA finishes or a phase

   *	mismatch occurs (which would finish the DMA transfer).

   *
   * Inputs : instance - this instance of the NCR5380.
   *
   */

  static void NCR5380_dma_complete(struct Scsi_Host *instance)

  {

  	SETUP_HOSTDATA(instance);
  	int transfered, saved_data = 0, overrun = 0, cnt, toPIO;
  	unsigned char **data, p;
  	volatile int *count;
  
  	if (!hostdata->connected) {
  		printk(KERN_WARNING "scsi%d: received end of DMA interrupt with "
  		       "no connected cmd
  ", HOSTNO);
  		return;

  	}

  
  	if (atari_read_overruns) {
  		p = hostdata->connected->SCp.phase;
  		if (p & SR_IO) {
  			udelay(10);
  			if ((NCR5380_read(BUS_AND_STATUS_REG) &
  			     (BASR_PHASE_MATCH|BASR_ACK)) ==
  			    (BASR_PHASE_MATCH|BASR_ACK)) {
  				saved_data = NCR5380_read(INPUT_DATA_REG);
  				overrun = 1;
  				DMA_PRINTK("scsi%d: read overrun handled
  ", HOSTNO);
  			}
  		}
  	}
  
  	DMA_PRINTK("scsi%d: real DMA transfer complete, basr 0x%X, sr 0x%X
  ",
  		   HOSTNO, NCR5380_read(BUS_AND_STATUS_REG),
  		   NCR5380_read(STATUS_REG));
  
  	(void)NCR5380_read(RESET_PARITY_INTERRUPT_REG);
  	NCR5380_write(MODE_REG, MR_BASE);
  	NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
  
  	transfered = hostdata->dma_len - NCR5380_dma_residual(instance);
  	hostdata->dma_len = 0;
  
  	data = (unsigned char **)&hostdata->connected->SCp.ptr;
  	count = &hostdata->connected->SCp.this_residual;
  	*data += transfered;
  	*count -= transfered;
  
  	if (atari_read_overruns) {
  		if ((NCR5380_read(STATUS_REG) & PHASE_MASK) == p && (p & SR_IO)) {
  			cnt = toPIO = atari_read_overruns;
  			if (overrun) {
  				DMA_PRINTK("Got an input overrun, using saved byte
  ");
  				*(*data)++ = saved_data;
  				(*count)--;
  				cnt--;
  				toPIO--;
  			}
  			DMA_PRINTK("Doing %d-byte PIO to 0x%08lx
  ", cnt, (long)*data);
  			NCR5380_transfer_pio(instance, &p, &cnt, data);
  			*count -= toPIO - cnt;
  		}

  	}

  }
  #endif /* REAL_DMA */
  
  
  /*
   * Function : void NCR5380_intr (int irq)

   *

   * Purpose : handle interrupts, reestablishing I_T_L or I_T_L_Q nexuses

   *	from the disconnected queue, and restarting NCR5380_main()

   *	as required.
   *
   * Inputs : int irq, irq that caused this interrupt.
   *
   */

  static irqreturn_t NCR5380_intr(int irq, void *dev_id)

  {

  	struct Scsi_Host *instance = first_instance;
  	int done = 1, handled = 0;
  	unsigned char basr;
  
  	INT_PRINTK("scsi%d: NCR5380 irq triggered
  ", HOSTNO);
  
  	/* Look for pending interrupts */
  	basr = NCR5380_read(BUS_AND_STATUS_REG);
  	INT_PRINTK("scsi%d: BASR=%02x
  ", HOSTNO, basr);
  	/* dispatch to appropriate routine if found and done=0 */
  	if (basr & BASR_IRQ) {
  		NCR_PRINT(NDEBUG_INTR);
  		if ((NCR5380_read(STATUS_REG) & (SR_SEL|SR_IO)) == (SR_SEL|SR_IO)) {
  			done = 0;
  			ENABLE_IRQ();
  			INT_PRINTK("scsi%d: SEL interrupt
  ", HOSTNO);
  			NCR5380_reselect(instance);
  			(void)NCR5380_read(RESET_PARITY_INTERRUPT_REG);
  		} else if (basr & BASR_PARITY_ERROR) {
  			INT_PRINTK("scsi%d: PARITY interrupt
  ", HOSTNO);
  			(void)NCR5380_read(RESET_PARITY_INTERRUPT_REG);
  		} else if ((NCR5380_read(STATUS_REG) & SR_RST) == SR_RST) {
  			INT_PRINTK("scsi%d: RESET interrupt
  ", HOSTNO);
  			(void)NCR5380_read(RESET_PARITY_INTERRUPT_REG);
  		} else {
  			/*
  			 * The rest of the interrupt conditions can occur only during a
  			 * DMA transfer
  			 */

  
  #if defined(REAL_DMA)

  			/*
  			 * We should only get PHASE MISMATCH and EOP interrupts if we have
  			 * DMA enabled, so do a sanity check based on the current setting
  			 * of the MODE register.
  			 */
  
  			if ((NCR5380_read(MODE_REG) & MR_DMA_MODE) &&
  			    ((basr & BASR_END_DMA_TRANSFER) ||
  			     !(basr & BASR_PHASE_MATCH))) {
  
  				INT_PRINTK("scsi%d: PHASE MISM or EOP interrupt
  ", HOSTNO);
  				NCR5380_dma_complete( instance );
  				done = 0;
  				ENABLE_IRQ();
  			} else

  #endif /* REAL_DMA */

  			{

  /* MS: Ignore unknown phase mismatch interrupts (caused by EOP interrupt) */

  				if (basr & BASR_PHASE_MATCH)
  					printk(KERN_NOTICE "scsi%d: unknown interrupt, "
  					       "BASR 0x%x, MR 0x%x, SR 0x%x
  ",
  					       HOSTNO, basr, NCR5380_read(MODE_REG),
  					       NCR5380_read(STATUS_REG));
  				(void)NCR5380_read(RESET_PARITY_INTERRUPT_REG);
  			}
  		} /* if !(SELECTION || PARITY) */
  		handled = 1;
  	} /* BASR & IRQ */ else {
  		printk(KERN_NOTICE "scsi%d: interrupt without IRQ bit set in BASR, "
  		       "BASR 0x%X, MR 0x%X, SR 0x%x
  ", HOSTNO, basr,
  		       NCR5380_read(MODE_REG), NCR5380_read(STATUS_REG));
  		(void)NCR5380_read(RESET_PARITY_INTERRUPT_REG);
  	}
  
  	if (!done) {
  		INT_PRINTK("scsi%d: in int routine, calling main
  ", HOSTNO);
  		/* Put a call to NCR5380_main() on the queue... */
  		queue_main();
  	}
  	return IRQ_RETVAL(handled);

  }
  
  #ifdef NCR5380_STATS

  static void collect_stats(struct NCR5380_hostdata* hostdata, Scsi_Cmnd *cmd)

  {
  # ifdef NCR5380_STAT_LIMIT

  	if (scsi_bufflen(cmd) > NCR5380_STAT_LIMIT)

  # endif

  		switch (cmd->cmnd[0]) {
  		case WRITE:
  		case WRITE_6:
  		case WRITE_10:
  			hostdata->time_write[cmd->device->id] += (jiffies - hostdata->timebase);

  			/*hostdata->bytes_write[cmd->device->id] += scsi_bufflen(cmd);*/

  			hostdata->pendingw--;
  			break;
  		case READ:
  		case READ_6:
  		case READ_10:
  			hostdata->time_read[cmd->device->id] += (jiffies - hostdata->timebase);

  			/*hostdata->bytes_read[cmd->device->id] += scsi_bufflen(cmd);*/

  			hostdata->pendingr--;
  			break;
  		}

  }
  #endif

  /*
   * Function : int NCR5380_select (struct Scsi_Host *instance, Scsi_Cmnd *cmd,

   *	int tag);
   *
   * Purpose : establishes I_T_L or I_T_L_Q nexus for new or existing command,

   *	including ARBITRATION, SELECTION, and initial message out for
   *	IDENTIFY and queue messages.

   *

   * Inputs : instance - instantiation of the 5380 driver on which this
   *	target lives, cmd - SCSI command to execute, tag - set to TAG_NEXT for
   *	new tag, TAG_NONE for untagged queueing, otherwise set to the tag for

   *	the command that is presently connected.

   *

   * Returns : -1 if selection could not execute for some reason,

   *	0 if selection succeeded or failed because the target
   *	did not respond.

   *

   * Side effects :
   *	If bus busy, arbitration failed, etc, NCR5380_select() will exit

   *		with registers as they should have been on entry - ie
   *		SELECT_ENABLE will be set appropriately, the NCR5380
   *		will cease to drive any SCSI bus signals.
   *

   *	If successful : I_T_L or I_T_L_Q nexus will be established,
   *		instance->connected will be set to cmd.
   *		SELECT interrupt will be disabled.

   *

   *	If failed (no target) : cmd->scsi_done() will be called, and the

   *		cmd->result host byte set to DID_BAD_TARGET.
   */

  static int NCR5380_select(struct Scsi_Host *instance, Scsi_Cmnd *cmd, int tag)

  {

  	SETUP_HOSTDATA(instance);
  	unsigned char tmp[3], phase;
  	unsigned char *data;
  	int len;
  	unsigned long timeout;
  	unsigned long flags;
  
  	hostdata->restart_select = 0;
  	NCR_PRINT(NDEBUG_ARBITRATION);
  	ARB_PRINTK("scsi%d: starting arbitration, id = %d
  ", HOSTNO,
  		   instance->this_id);
  
  	/*
  	 * Set the phase bits to 0, otherwise the NCR5380 won't drive the
  	 * data bus during SELECTION.
  	 */
  
  	local_irq_save(flags);
  	if (hostdata->connected) {
  		local_irq_restore(flags);
  		return -1;
  	}
  	NCR5380_write(TARGET_COMMAND_REG, 0);

  	/*
  	 * Start arbitration.
  	 */

  	NCR5380_write(OUTPUT_DATA_REG, hostdata->id_mask);
  	NCR5380_write(MODE_REG, MR_ARBITRATE);

  	local_irq_restore(flags);

  	/* Wait for arbitration logic to complete */

  #if defined(NCR_TIMEOUT)

  	{
  		unsigned long timeout = jiffies + 2*NCR_TIMEOUT;
  
  		while (!(NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_PROGRESS) &&
  		       time_before(jiffies, timeout) && !hostdata->connected)
  			;
  		if (time_after_eq(jiffies, timeout)) {
  			printk("scsi : arbitration timeout at %d
  ", __LINE__);
  			NCR5380_write(MODE_REG, MR_BASE);
  			NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
  			return -1;
  		}
  	}

  #else /* NCR_TIMEOUT */

  	while (!(NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_PROGRESS) &&
  	       !hostdata->connected)
  		;

  #endif

  	ARB_PRINTK("scsi%d: arbitration complete
  ", HOSTNO);
  
  	if (hostdata->connected) {
  		NCR5380_write(MODE_REG, MR_BASE);
  		return -1;
  	}
  	/*
  	 * The arbitration delay is 2.2us, but this is a minimum and there is
  	 * no maximum so we can safely sleep for ceil(2.2) usecs to accommodate
  	 * the integral nature of udelay().
  	 *
  	 */
  
  	udelay(3);
  
  	/* Check for lost arbitration */
  	if ((NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_LOST) ||
  	    (NCR5380_read(CURRENT_SCSI_DATA_REG) & hostdata->id_higher_mask) ||
  	    (NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_LOST) ||
  	    hostdata->connected) {
  		NCR5380_write(MODE_REG, MR_BASE);
  		ARB_PRINTK("scsi%d: lost arbitration, deasserting MR_ARBITRATE
  ",
  			   HOSTNO);
  		return -1;
  	}

  	/* after/during arbitration, BSY should be asserted.
  	   IBM DPES-31080 Version S31Q works now */
  	/* Tnx to Thomas_Roesch@m2.maus.de for finding this! (Roman) */
  	NCR5380_write(INITIATOR_COMMAND_REG,
  		      ICR_BASE | ICR_ASSERT_SEL | ICR_ASSERT_BSY);
  
  	if ((NCR5380_read(INITIATOR_COMMAND_REG) & ICR_ARBITRATION_LOST) ||
  	    hostdata->connected) {
  		NCR5380_write(MODE_REG, MR_BASE);
  		NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
  		ARB_PRINTK("scsi%d: lost arbitration, deasserting ICR_ASSERT_SEL
  ",
  			   HOSTNO);
  		return -1;
  	}
  
  	/*
  	 * Again, bus clear + bus settle time is 1.2us, however, this is
  	 * a minimum so we'll udelay ceil(1.2)
  	 */

  
  #ifdef CONFIG_ATARI_SCSI_TOSHIBA_DELAY

  	/* ++roman: But some targets (see above :-) seem to need a bit more... */
  	udelay(15);

  #else

  	udelay(2);

  #endif

  
  	if (hostdata->connected) {
  		NCR5380_write(MODE_REG, MR_BASE);
  		NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
  		return -1;
  	}
  
  	ARB_PRINTK("scsi%d: won arbitration
  ", HOSTNO);
  
  	/*
  	 * Now that we have won arbitration, start Selection process, asserting
  	 * the host and target ID's on the SCSI bus.
  	 */
  
  	NCR5380_write(OUTPUT_DATA_REG, (hostdata->id_mask | (1 << cmd->device->id)));
  
  	/*
  	 * Raise ATN while SEL is true before BSY goes false from arbitration,
  	 * since this is the only way to guarantee that we'll get a MESSAGE OUT
  	 * phase immediately after selection.
  	 */
  
  	NCR5380_write(INITIATOR_COMMAND_REG, (ICR_BASE | ICR_ASSERT_BSY |
  		      ICR_ASSERT_DATA | ICR_ASSERT_ATN | ICR_ASSERT_SEL ));

  	NCR5380_write(MODE_REG, MR_BASE);

  	/*
  	 * Reselect interrupts must be turned off prior to the dropping of BSY,
  	 * otherwise we will trigger an interrupt.
  	 */
  
  	if (hostdata->connected) {
  		NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
  		return -1;
  	}
  
  	NCR5380_write(SELECT_ENABLE_REG, 0);

  	/*
  	 * The initiator shall then wait at least two deskew delays and release
  	 * the BSY signal.
  	 */
  	udelay(1);        /* wingel -- wait two bus deskew delay >2*45ns */
  
  	/* Reset BSY */
  	NCR5380_write(INITIATOR_COMMAND_REG, (ICR_BASE | ICR_ASSERT_DATA |
  		      ICR_ASSERT_ATN | ICR_ASSERT_SEL));
  
  	/*
  	 * Something weird happens when we cease to drive BSY - looks
  	 * like the board/chip is letting us do another read before the
  	 * appropriate propagation delay has expired, and we're confusing
  	 * a BSY signal from ourselves as the target's response to SELECTION.
  	 *
  	 * A small delay (the 'C++' frontend breaks the pipeline with an
  	 * unnecessary jump, making it work on my 386-33/Trantor T128, the
  	 * tighter 'C' code breaks and requires this) solves the problem -
  	 * the 1 us delay is arbitrary, and only used because this delay will
  	 * be the same on other platforms and since it works here, it should
  	 * work there.
  	 *
  	 * wingel suggests that this could be due to failing to wait
  	 * one deskew delay.
  	 */

  	udelay(1);

  	SEL_PRINTK("scsi%d: selecting target %d
  ", HOSTNO, cmd->device->id);

  	/*
  	 * The SCSI specification calls for a 250 ms timeout for the actual
  	 * selection.
  	 */

  	timeout = jiffies + 25;

  	/*
  	 * XXX very interesting - we're seeing a bounce where the BSY we
  	 * asserted is being reflected / still asserted (propagation delay?)
  	 * and it's detecting as true.  Sigh.
  	 */

  
  #if 0

  	/* ++roman: If a target conformed to the SCSI standard, it wouldn't assert
  	 * IO while SEL is true. But again, there are some disks out the in the
  	 * world that do that nevertheless. (Somebody claimed that this announces
  	 * reselection capability of the target.) So we better skip that test and
  	 * only wait for BSY... (Famous german words: Der Klügere gibt nach :-)
  	 */
  
  	while (time_before(jiffies, timeout) &&
  	       !(NCR5380_read(STATUS_REG) & (SR_BSY | SR_IO)))
  		;
  
  	if ((NCR5380_read(STATUS_REG) & (SR_SEL | SR_IO)) == (SR_SEL | SR_IO)) {
  		NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
  		NCR5380_reselect(instance);
  		printk(KERN_ERR "scsi%d: reselection after won arbitration?
  ",
  		       HOSTNO);
  		NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
  		return -1;
  	}

  #else

  	while (time_before(jiffies, timeout) && !(NCR5380_read(STATUS_REG) & SR_BSY))
  		;

  #endif

  	/*
  	 * No less than two deskew delays after the initiator detects the
  	 * BSY signal is true, it shall release the SEL signal and may
  	 * change the DATA BUS.                                     -wingel
  	 */

  	udelay(1);

  	NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ATN);

  	if (!(NCR5380_read(STATUS_REG) & SR_BSY)) {
  		NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
  		if (hostdata->targets_present & (1 << cmd->device->id)) {
  			printk(KERN_ERR "scsi%d: weirdness
  ", HOSTNO);
  			if (hostdata->restart_select)
  				printk(KERN_NOTICE "\trestart select
  ");
  			NCR_PRINT(NDEBUG_ANY);
  			NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
  			return -1;
  		}
  		cmd->result = DID_BAD_TARGET << 16;

  #ifdef NCR5380_STATS

  		collect_stats(hostdata, cmd);

  #endif
  #ifdef SUPPORT_TAGS

  		cmd_free_tag(cmd);

  #endif

  		cmd->scsi_done(cmd);
  		NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
  		SEL_PRINTK("scsi%d: target did not respond within 250ms
  ", HOSTNO);
  		NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
  		return 0;
  	}
  
  	hostdata->targets_present |= (1 << cmd->device->id);
  
  	/*
  	 * Since we followed the SCSI spec, and raised ATN while SEL
  	 * was true but before BSY was false during selection, the information
  	 * transfer phase should be a MESSAGE OUT phase so that we can send the
  	 * IDENTIFY message.
  	 *
  	 * If SCSI-II tagged queuing is enabled, we also send a SIMPLE_QUEUE_TAG
  	 * message (2 bytes) with a tag ID that we increment with every command
  	 * until it wraps back to 0.
  	 *
  	 * XXX - it turns out that there are some broken SCSI-II devices,
  	 *	     which claim to support tagged queuing but fail when more than
  	 *	     some number of commands are issued at once.
  	 */
  
  	/* Wait for start of REQ/ACK handshake */
  	while (!(NCR5380_read(STATUS_REG) & SR_REQ))
  		;
  
  	SEL_PRINTK("scsi%d: target %d selected, going into MESSAGE OUT phase.
  ",
  		   HOSTNO, cmd->device->id);
  	tmp[0] = IDENTIFY(1, cmd->device->lun);

  
  #ifdef SUPPORT_TAGS

  	if (cmd->tag != TAG_NONE) {
  		tmp[1] = hostdata->last_message = SIMPLE_QUEUE_TAG;
  		tmp[2] = cmd->tag;
  		len = 3;
  	} else
  		len = 1;

  #else

  	len = 1;
  	cmd->tag = 0;

  #endif /* SUPPORT_TAGS */

  	/* Send message(s) */
  	data = tmp;
  	phase = PHASE_MSGOUT;
  	NCR5380_transfer_pio(instance, &phase, &len, &data);
  	SEL_PRINTK("scsi%d: nexus established.
  ", HOSTNO);
  	/* XXX need to handle errors here */
  	hostdata->connected = cmd;

  #ifndef SUPPORT_TAGS

  	hostdata->busy[cmd->device->id] |= (1 << cmd->device->lun);
  #endif

  	initialize_SCp(cmd);

  	return 0;

  }

  /*
   * Function : int NCR5380_transfer_pio (struct Scsi_Host *instance,

   *      unsigned char *phase, int *count, unsigned char **data)
   *
   * Purpose : transfers data in given phase using polled I/O
   *

   * Inputs : instance - instance of driver, *phase - pointer to
   *	what phase is expected, *count - pointer to number of

   *	bytes to transfer, **data - pointer to data pointer.

   *

   * Returns : -1 when different phase is entered without transferring

   *	maximum number of bytes, 0 if all bytes are transferred or exit

   *	is in same phase.
   *

   *	Also, *phase, *count, *data are modified in place.

   *
   * XXX Note : handling for bus free may be useful.
   */
  
  /*

   * Note : this code is not as quick as it could be, however it

   * IS 100% reliable, and for the actual data transfer where speed
   * counts, we will always do a pseudo DMA or DMA transfer.
   */

  static int NCR5380_transfer_pio(struct Scsi_Host *instance,
  				unsigned char *phase, int *count,
  				unsigned char **data)

  {

  	register unsigned char p = *phase, tmp;
  	register int c = *count;
  	register unsigned char *d = *data;
  
  	/*
  	 * The NCR5380 chip will only drive the SCSI bus when the
  	 * phase specified in the appropriate bits of the TARGET COMMAND
  	 * REGISTER match the STATUS REGISTER

  	 */

  	NCR5380_write(TARGET_COMMAND_REG, PHASE_SR_TO_TCR(p));

  	do {
  		/*
  		 * Wait for assertion of REQ, after which the phase bits will be
  		 * valid
  		 */
  		while (!((tmp = NCR5380_read(STATUS_REG)) & SR_REQ))
  			;

  		HSH_PRINTK("scsi%d: REQ detected
  ", HOSTNO);

  		/* Check for phase mismatch */
  		if ((tmp & PHASE_MASK) != p) {
  			PIO_PRINTK("scsi%d: phase mismatch
  ", HOSTNO);
  			NCR_PRINT_PHASE(NDEBUG_PIO);
  			break;
  		}

  		/* Do actual transfer from SCSI bus to / from memory */
  		if (!(p & SR_IO))
  			NCR5380_write(OUTPUT_DATA_REG, *d);
  		else
  			*d = NCR5380_read(CURRENT_SCSI_DATA_REG);

  		++d;

  		/*
  		 * The SCSI standard suggests that in MSGOUT phase, the initiator
  		 * should drop ATN on the last byte of the message phase
  		 * after REQ has been asserted for the handshake but before
  		 * the initiator raises ACK.
  		 */

  		if (!(p & SR_IO)) {
  			if (!((p & SR_MSG) && c > 1)) {
  				NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_DATA);
  				NCR_PRINT(NDEBUG_PIO);
  				NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE |
  					      ICR_ASSERT_DATA | ICR_ASSERT_ACK);
  			} else {
  				NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE |
  					      ICR_ASSERT_DATA | ICR_ASSERT_ATN);
  				NCR_PRINT(NDEBUG_PIO);
  				NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE |
  					      ICR_ASSERT_DATA | ICR_ASSERT_ATN | ICR_ASSERT_ACK);
  			}
  		} else {
  			NCR_PRINT(NDEBUG_PIO);
  			NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ACK);
  		}

  		while (NCR5380_read(STATUS_REG) & SR_REQ)
  			;
  
  		HSH_PRINTK("scsi%d: req false, handshake complete
  ", HOSTNO);
  
  		/*
  		 * We have several special cases to consider during REQ/ACK handshaking :
  		 * 1.  We were in MSGOUT phase, and we are on the last byte of the
  		 *	message.  ATN must be dropped as ACK is dropped.
  		 *
  		 * 2.  We are in a MSGIN phase, and we are on the last byte of the
  		 *	message.  We must exit with ACK asserted, so that the calling
  		 *	code may raise ATN before dropping ACK to reject the message.
  		 *
  		 * 3.  ACK and ATN are clear and the target may proceed as normal.
  		 */
  		if (!(p == PHASE_MSGIN && c == 1)) {
  			if (p == PHASE_MSGOUT && c > 1)
  				NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ATN);
  			else
  				NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
  		}
  	} while (--c);
  
  	PIO_PRINTK("scsi%d: residual %d
  ", HOSTNO, c);
  
  	*count = c;
  	*data = d;
  	tmp = NCR5380_read(STATUS_REG);
  	/* The phase read from the bus is valid if either REQ is (already)
  	 * asserted or if ACK hasn't been released yet. The latter is the case if
  	 * we're in MSGIN and all wanted bytes have been received.
  	 */
  	if ((tmp & SR_REQ) || (p == PHASE_MSGIN && c == 0))
  		*phase = tmp & PHASE_MASK;
  	else
  		*phase = PHASE_UNKNOWN;
  
  	if (!c || (*phase == p))
  		return 0;
  	else
  		return -1;

  }
  
  /*
   * Function : do_abort (Scsi_Host *host)

   *
   * Purpose : abort the currently established nexus.  Should only be
   *	called from a routine which can drop into a
   *

   * Returns : 0 on success, -1 on failure.
   */

  static int do_abort(struct Scsi_Host *host)

  {

  	unsigned char tmp, *msgptr, phase;
  	int len;
  
  	/* Request message out phase */

  	NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ATN);

  
  	/*
  	 * Wait for the target to indicate a valid phase by asserting
  	 * REQ.  Once this happens, we'll have either a MSGOUT phase
  	 * and can immediately send the ABORT message, or we'll have some
  	 * other phase and will have to source/sink data.
  	 *
  	 * We really don't care what value was on the bus or what value
  	 * the target sees, so we just handshake.
  	 */

  	while (!((tmp = NCR5380_read(STATUS_REG)) & SR_REQ))

  		;
  
  	NCR5380_write(TARGET_COMMAND_REG, PHASE_SR_TO_TCR(tmp));
  
  	if ((tmp & PHASE_MASK) != PHASE_MSGOUT) {
  		NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ATN |
  			      ICR_ASSERT_ACK);
  		while (NCR5380_read(STATUS_REG) & SR_REQ)
  			;
  		NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ATN);
  	}
  
  	tmp = ABORT;
  	msgptr = &tmp;
  	len = 1;
  	phase = PHASE_MSGOUT;
  	NCR5380_transfer_pio(host, &phase, &len, &msgptr);
  
  	/*
  	 * If we got here, and the command completed successfully,
  	 * we're about to go into bus free state.
  	 */
  
  	return len ? -1 : 0;

  }
  
  #if defined(REAL_DMA)

  /*
   * Function : int NCR5380_transfer_dma (struct Scsi_Host *instance,

   *      unsigned char *phase, int *count, unsigned char **data)
   *
   * Purpose : transfers data in given phase using either real
   *	or pseudo DMA.
   *

   * Inputs : instance - instance of driver, *phase - pointer to
   *	what phase is expected, *count - pointer to number of

   *	bytes to transfer, **data - pointer to data pointer.

   *

   * Returns : -1 when different phase is entered without transferring

   *	maximum number of bytes, 0 if all bytes or transferred or exit

   *	is in same phase.
   *

   *	Also, *phase, *count, *data are modified in place.

   *
   */

  static int NCR5380_transfer_dma(struct Scsi_Host *instance,
  				unsigned char *phase, int *count,
  				unsigned char **data)

  {

  	SETUP_HOSTDATA(instance);
  	register int c = *count;
  	register unsigned char p = *phase;
  	register unsigned char *d = *data;
  	unsigned char tmp;
  	unsigned long flags;
  
  	if ((tmp = (NCR5380_read(STATUS_REG) & PHASE_MASK)) != p) {
  		*phase = tmp;
  		return -1;
  	}

  	if (atari_read_overruns && (p & SR_IO))
  		c -= atari_read_overruns;

  	DMA_PRINTK("scsi%d: initializing DMA for %s, %d bytes %s %p
  ",
  		   HOSTNO, (p & SR_IO) ? "reading" : "writing",
  		   c, (p & SR_IO) ? "to" : "from", d);

  	NCR5380_write(TARGET_COMMAND_REG, PHASE_SR_TO_TCR(p));

  
  #ifdef REAL_DMA

  	NCR5380_write(MODE_REG, MR_BASE | MR_DMA_MODE | MR_ENABLE_EOP_INTR | MR_MONITOR_BSY);

  #endif /* def REAL_DMA  */

  	if (IS_A_TT()) {
  		/* On the Medusa, it is a must to initialize the DMA before
  		 * starting the NCR. This is also the cleaner way for the TT.
  		 */
  		local_irq_save(flags);
  		hostdata->dma_len = (p & SR_IO) ?
  			NCR5380_dma_read_setup(instance, d, c) :
  			NCR5380_dma_write_setup(instance, d, c);
  		local_irq_restore(flags);
  	}
  
  	if (p & SR_IO)
  		NCR5380_write(START_DMA_INITIATOR_RECEIVE_REG, 0);
  	else {
  		NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_DATA);
  		NCR5380_write(START_DMA_SEND_REG, 0);
  	}
  
  	if (!IS_A_TT()) {
  		/* On the Falcon, the DMA setup must be done after the last */
  		/* NCR access, else the DMA setup gets trashed!
  		 */
  		local_irq_save(flags);
  		hostdata->dma_len = (p & SR_IO) ?
  			NCR5380_dma_read_setup(instance, d, c) :
  			NCR5380_dma_write_setup(instance, d, c);
  		local_irq_restore(flags);
  	}
  	return 0;

  }
  #endif /* defined(REAL_DMA) */
  
  /*
   * Function : NCR5380_information_transfer (struct Scsi_Host *instance)
   *

   * Purpose : run through the various SCSI phases and do as the target
   *	directs us to.  Operates on the currently connected command,

   *	instance->connected.
   *
   * Inputs : instance, instance for which we are doing commands
   *

   * Side effects : SCSI things happen, the disconnected queue will be

   *	modified if a command disconnects, *instance->connected will
   *	change.
   *

   * XXX Note : we need to watch for bus free or a reset condition here
   *	to recover from an unexpected bus free condition.

   */

  
  static void NCR5380_information_transfer(struct Scsi_Host *instance)

  {

  	SETUP_HOSTDATA(instance);
  	unsigned long flags;
  	unsigned char msgout = NOP;
  	int sink = 0;
  	int len;

  #if defined(REAL_DMA)

  	int transfersize;

  #endif

  	unsigned char *data;
  	unsigned char phase, tmp, extended_msg[10], old_phase = 0xff;
  	Scsi_Cmnd *cmd = (Scsi_Cmnd *) hostdata->connected;
  
  	while (1) {
  		tmp = NCR5380_read(STATUS_REG);
  		/* We only have a valid SCSI phase when REQ is asserted */
  		if (tmp & SR_REQ) {
  			phase = (tmp & PHASE_MASK);
  			if (phase != old_phase) {
  				old_phase = phase;
  				NCR_PRINT_PHASE(NDEBUG_INFORMATION);
  			}

  			if (sink && (phase != PHASE_MSGOUT)) {
  				NCR5380_write(TARGET_COMMAND_REG, PHASE_SR_TO_TCR(tmp));
  
  				NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ATN |
  					      ICR_ASSERT_ACK);
  				while (NCR5380_read(STATUS_REG) & SR_REQ)
  					;
  				NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE |
  					      ICR_ASSERT_ATN);
  				sink = 0;
  				continue;
  			}
  
  			switch (phase) {
  			case PHASE_DATAOUT:

  #if (NDEBUG & NDEBUG_NO_DATAOUT)

  				printk("scsi%d: NDEBUG_NO_DATAOUT set, attempted DATAOUT "
  				       "aborted
  ", HOSTNO);
  				sink = 1;
  				do_abort(instance);
  				cmd->result = DID_ERROR << 16;

  				cmd->scsi_done(cmd);

  				return;

  #endif

  			case PHASE_DATAIN:
  				/*
  				 * If there is no room left in the current buffer in the
  				 * scatter-gather list, move onto the next one.
  				 */
  
  				if (!cmd->SCp.this_residual && cmd->SCp.buffers_residual) {
  					++cmd->SCp.buffer;
  					--cmd->SCp.buffers_residual;
  					cmd->SCp.this_residual = cmd->SCp.buffer->length;

  					cmd->SCp.ptr = sg_virt(cmd->SCp.buffer);

  					/* ++roman: Try to merge some scatter-buffers if
  					 * they are at contiguous physical addresses.
  					 */
  					merge_contiguous_buffers(cmd);
  					INF_PRINTK("scsi%d: %d bytes and %d buffers left
  ",
  						   HOSTNO, cmd->SCp.this_residual,
  						   cmd->SCp.buffers_residual);
  				}
  
  				/*
  				 * The preferred transfer method is going to be
  				 * PSEUDO-DMA for systems that are strictly PIO,
  				 * since we can let the hardware do the handshaking.
  				 *
  				 * For this to work, we need to know the transfersize
  				 * ahead of time, since the pseudo-DMA code will sit
  				 * in an unconditional loop.
  				 */
  
  				/* ++roman: I suggest, this should be
  				 *   #if def(REAL_DMA)
  				 * instead of leaving REAL_DMA out.
  				 */

  
  #if defined(REAL_DMA)

  				if (!cmd->device->borken &&
  				    (transfersize = NCR5380_dma_xfer_len(instance,cmd,phase)) > 31) {
  					len = transfersize;
  					cmd->SCp.phase = phase;
  					if (NCR5380_transfer_dma(instance, &phase,
  					    &len, (unsigned char **)&cmd->SCp.ptr)) {
  						/*
  						 * If the watchdog timer fires, all future
  						 * accesses to this device will use the
  						 * polled-IO. */
  						printk(KERN_NOTICE "scsi%d: switching target %d "
  							   "lun %d to slow handshake
  ", HOSTNO,
  							   cmd->device->id, cmd->device->lun);
  						cmd->device->borken = 1;
  						NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE |
  							ICR_ASSERT_ATN);
  						sink = 1;
  						do_abort(instance);
  						cmd->result = DID_ERROR << 16;

  						cmd->scsi_done(cmd);

  						/* XXX - need to source or sink data here, as appropriate */
  					} else {

  #ifdef REAL_DMA

  						/* ++roman: When using real DMA,
  						 * information_transfer() should return after
  						 * starting DMA since it has nothing more to
  						 * do.
  						 */
  						return;
  #else
  						cmd->SCp.this_residual -= transfersize - len;

  #endif

  					}
  				} else

  #endif /* defined(REAL_DMA) */

  					NCR5380_transfer_pio(instance, &phase,
  							     (int *)&cmd->SCp.this_residual,
  							     (unsigned char **)&cmd->SCp.ptr);
  				break;
  			case PHASE_MSGIN:
  				len = 1;
  				data = &tmp;
  				NCR5380_write(SELECT_ENABLE_REG, 0);	/* disable reselects */
  				NCR5380_transfer_pio(instance, &phase, &len, &data);
  				cmd->SCp.Message = tmp;
  
  				switch (tmp) {
  				/*
  				 * Linking lets us reduce the time required to get the
  				 * next command out to the device, hopefully this will
  				 * mean we don't waste another revolution due to the delays
  				 * required by ARBITRATION and another SELECTION.
  				 *
  				 * In the current implementation proposal, low level drivers
  				 * merely have to start the next command, pointed to by
  				 * next_link, done() is called as with unlinked commands.
  				 */

  #ifdef LINKED

  				case LINKED_CMD_COMPLETE:
  				case LINKED_FLG_CMD_COMPLETE:
  					/* Accept message by clearing ACK */
  					NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
  
  					LNK_PRINTK("scsi%d: target %d lun %d linked command "
  						   "complete.
  ", HOSTNO, cmd->device->id, cmd->device->lun);
  
  					/* Enable reselect interrupts */
  					NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
  					/*
  					 * Sanity check : A linked command should only terminate
  					 * with one of these messages if there are more linked
  					 * commands available.
  					 */
  
  					if (!cmd->next_link) {
  						 printk(KERN_NOTICE "scsi%d: target %d lun %d "
  							"linked command complete, no next_link
  ",
  							HOSTNO, cmd->device->id, cmd->device->lun);
  						sink = 1;
  						do_abort(instance);
  						return;
  					}
  
  					initialize_SCp(cmd->next_link);
  					/* The next command is still part of this process; copy it
  					 * and don't free it! */
  					cmd->next_link->tag = cmd->tag;
  					cmd->result = cmd->SCp.Status | (cmd->SCp.Message << 8);
  					LNK_PRINTK("scsi%d: target %d lun %d linked request "
  						   "done, calling scsi_done().
  ",
  						   HOSTNO, cmd->device->id, cmd->device->lun);

  #ifdef NCR5380_STATS

  					collect_stats(hostdata, cmd);

  #endif

  					cmd->scsi_done(cmd);
  					cmd = hostdata->connected;
  					break;

  #endif /* def LINKED */

  				case ABORT:
  				case COMMAND_COMPLETE:
  					/* Accept message by clearing ACK */
  					NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
  					/* ++guenther: possible race with Falcon locking */
  					falcon_dont_release++;
  					hostdata->connected = NULL;
  					QU_PRINTK("scsi%d: command for target %d, lun %d "
  						  "completed
  ", HOSTNO, cmd->device->id, cmd->device->lun);

  #ifdef SUPPORT_TAGS

  					cmd_free_tag(cmd);
  					if (status_byte(cmd->SCp.Status) == QUEUE_FULL) {
  						/* Turn a QUEUE FULL status into BUSY, I think the
  						 * mid level cannot handle QUEUE FULL :-( (The
  						 * command is retried after BUSY). Also update our
  						 * queue size to the number of currently issued
  						 * commands now.
  						 */
  						/* ++Andreas: the mid level code knows about
  						   QUEUE_FULL now. */
  						TAG_ALLOC *ta = &TagAlloc[cmd->device->id][cmd->device->lun];
  						TAG_PRINTK("scsi%d: target %d lun %d returned "
  							   "QUEUE_FULL after %d commands
  ",
  							   HOSTNO, cmd->device->id, cmd->device->lun,
  							   ta->nr_allocated);
  						if (ta->queue_size > ta->nr_allocated)
  							ta->nr_allocated = ta->queue_size;
  					}

  #else

  					hostdata->busy[cmd->device->id] &= ~(1 << cmd->device->lun);

  #endif

  					/* Enable reselect interrupts */
  					NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
  
  					/*
  					 * I'm not sure what the correct thing to do here is :
  					 *
  					 * If the command that just executed is NOT a request
  					 * sense, the obvious thing to do is to set the result
  					 * code to the values of the stored parameters.
  					 *
  					 * If it was a REQUEST SENSE command, we need some way to
  					 * differentiate between the failure code of the original
  					 * and the failure code of the REQUEST sense - the obvious
  					 * case is success, where we fall through and leave the
  					 * result code unchanged.
  					 *
  					 * The non-obvious place is where the REQUEST SENSE failed
  					 */
  
  					if (cmd->cmnd[0] != REQUEST_SENSE)
  						cmd->result = cmd->SCp.Status | (cmd->SCp.Message << 8);
  					else if (status_byte(cmd->SCp.Status) != GOOD)
  						cmd->result = (cmd->result & 0x00ffff) | (DID_ERROR << 16);

  #ifdef AUTOSENSE

  					if ((cmd->cmnd[0] == REQUEST_SENSE) &&
  						hostdata->ses.cmd_len) {
  						scsi_eh_restore_cmnd(cmd, &hostdata->ses);
  						hostdata->ses.cmd_len = 0 ;
  					}

  					if ((cmd->cmnd[0] != REQUEST_SENSE) &&
  					    (status_byte(cmd->SCp.Status) == CHECK_CONDITION)) {

  						scsi_eh_prep_cmnd(cmd, &hostdata->ses, NULL, 0, ~0);

  						ASEN_PRINTK("scsi%d: performing request sense
  ", HOSTNO);

  
  						local_irq_save(flags);
  						LIST(cmd,hostdata->issue_queue);

  						SET_NEXT(cmd, hostdata->issue_queue);

  						hostdata->issue_queue = (Scsi_Cmnd *) cmd;
  						local_irq_restore(flags);
  						QU_PRINTK("scsi%d: REQUEST SENSE added to head of "
  							  "issue queue
  ", H_NO(cmd));
  					} else

  #endif /* def AUTOSENSE */

  					{

  #ifdef NCR5380_STATS

  						collect_stats(hostdata, cmd);

  #endif

  						cmd->scsi_done(cmd);
  					}
  
  					NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
  					/*
  					 * Restore phase bits to 0 so an interrupted selection,
  					 * arbitration can resume.
  					 */
  					NCR5380_write(TARGET_COMMAND_REG, 0);
  
  					while ((NCR5380_read(STATUS_REG) & SR_BSY) && !hostdata->connected)
  						barrier();
  
  					falcon_dont_release--;
  					/* ++roman: For Falcon SCSI, release the lock on the
  					 * ST-DMA here if no other commands are waiting on the
  					 * disconnected queue.
  					 */
  					falcon_release_lock_if_possible(hostdata);
  					return;
  				case MESSAGE_REJECT:
  					/* Accept message by clearing ACK */
  					NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
  					/* Enable reselect interrupts */
  					NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
  					switch (hostdata->last_message) {
  					case HEAD_OF_QUEUE_TAG:
  					case ORDERED_QUEUE_TAG:
  					case SIMPLE_QUEUE_TAG:
  						/* The target obviously doesn't support tagged
  						 * queuing, even though it announced this ability in
  						 * its INQUIRY data ?!? (maybe only this LUN?) Ok,
  						 * clear 'tagged_supported' and lock the LUN, since
  						 * the command is treated as untagged further on.
  						 */
  						cmd->device->tagged_supported = 0;
  						hostdata->busy[cmd->device->id] |= (1 << cmd->device->lun);
  						cmd->tag = TAG_NONE;
  						TAG_PRINTK("scsi%d: target %d lun %d rejected "
  							   "QUEUE_TAG message; tagged queuing "
  							   "disabled
  ",
  							   HOSTNO, cmd->device->id, cmd->device->lun);
  						break;
  					}
  					break;
  				case DISCONNECT:
  					/* Accept message by clearing ACK */
  					NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
  					local_irq_save(flags);
  					cmd->device->disconnect = 1;
  					LIST(cmd,hostdata->disconnected_queue);

  					SET_NEXT(cmd, hostdata->disconnected_queue);

  					hostdata->connected = NULL;
  					hostdata->disconnected_queue = cmd;
  					local_irq_restore(flags);
  					QU_PRINTK("scsi%d: command for target %d lun %d was "
  						  "moved from connected to the "
  						  "disconnected_queue
  ", HOSTNO,
  						  cmd->device->id, cmd->device->lun);
  					/*
  					 * Restore phase bits to 0 so an interrupted selection,
  					 * arbitration can resume.
  					 */
  					NCR5380_write(TARGET_COMMAND_REG, 0);
  
  					/* Enable reselect interrupts */
  					NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
  					/* Wait for bus free to avoid nasty timeouts */
  					while ((NCR5380_read(STATUS_REG) & SR_BSY) && !hostdata->connected)
  						barrier();
  					return;
  					/*
  					 * The SCSI data pointer is *IMPLICITLY* saved on a disconnect
  					 * operation, in violation of the SCSI spec so we can safely
  					 * ignore SAVE/RESTORE pointers calls.
  					 *
  					 * Unfortunately, some disks violate the SCSI spec and
  					 * don't issue the required SAVE_POINTERS message before
  					 * disconnecting, and we have to break spec to remain
  					 * compatible.
  					 */
  				case SAVE_POINTERS:
  				case RESTORE_POINTERS:
  					/* Accept message by clearing ACK */
  					NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
  					/* Enable reselect interrupts */
  					NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
  					break;
  				case EXTENDED_MESSAGE:
  					/*
  					 * Extended messages are sent in the following format :
  					 * Byte
  					 * 0		EXTENDED_MESSAGE == 1
  					 * 1		length (includes one byte for code, doesn't
  					 *		include first two bytes)
  					 * 2		code
  					 * 3..length+1	arguments
  					 *
  					 * Start the extended message buffer with the EXTENDED_MESSAGE
  					 * byte, since spi_print_msg() wants the whole thing.
  					 */
  					extended_msg[0] = EXTENDED_MESSAGE;
  					/* Accept first byte by clearing ACK */
  					NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
  
  					EXT_PRINTK("scsi%d: receiving extended message
  ", HOSTNO);
  
  					len = 2;
  					data = extended_msg + 1;
  					phase = PHASE_MSGIN;
  					NCR5380_transfer_pio(instance, &phase, &len, &data);
  					EXT_PRINTK("scsi%d: length=%d, code=0x%02x
  ", HOSTNO,
  						   (int)extended_msg[1], (int)extended_msg[2]);
  
  					if (!len && extended_msg[1] <=
  					    (sizeof(extended_msg) - 1)) {
  						/* Accept third byte by clearing ACK */
  						NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
  						len = extended_msg[1] - 1;
  						data = extended_msg + 3;
  						phase = PHASE_MSGIN;
  
  						NCR5380_transfer_pio(instance, &phase, &len, &data);
  						EXT_PRINTK("scsi%d: message received, residual %d
  ",
  							   HOSTNO, len);
  
  						switch (extended_msg[2]) {
  						case EXTENDED_SDTR:
  						case EXTENDED_WDTR:
  						case EXTENDED_MODIFY_DATA_POINTER:
  						case EXTENDED_EXTENDED_IDENTIFY:
  							tmp = 0;
  						}
  					} else if (len) {
  						printk(KERN_NOTICE "scsi%d: error receiving "
  						       "extended message
  ", HOSTNO);
  						tmp = 0;
  					} else {
  						printk(KERN_NOTICE "scsi%d: extended message "
  							   "code %02x length %d is too long
  ",
  							   HOSTNO, extended_msg[2], extended_msg[1]);
  						tmp = 0;
  					}
  					/* Fall through to reject message */
  
  					/*
  					 * If we get something weird that we aren't expecting,
  					 * reject it.
  					 */
  				default:
  					if (!tmp) {
  						printk(KERN_DEBUG "scsi%d: rejecting message ", HOSTNO);
  						spi_print_msg(extended_msg);
  						printk("
  ");
  					} else if (tmp != EXTENDED_MESSAGE)
  						printk(KERN_DEBUG "scsi%d: rejecting unknown "
  						       "message %02x from target %d, lun %d
  ",
  						       HOSTNO, tmp, cmd->device->id, cmd->device->lun);
  					else
  						printk(KERN_DEBUG "scsi%d: rejecting unknown "
  						       "extended message "
  						       "code %02x, length %d from target %d, lun %d
  ",
  						       HOSTNO, extended_msg[1], extended_msg[0],
  						       cmd->device->id, cmd->device->lun);
  
  
  					msgout = MESSAGE_REJECT;
  					NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_ATN);
  					break;
  				} /* switch (tmp) */
  				break;
  			case PHASE_MSGOUT:
  				len = 1;
  				data = &msgout;
  				hostdata->last_message = msgout;
  				NCR5380_transfer_pio(instance, &phase, &len, &data);
  				if (msgout == ABORT) {

  #ifdef SUPPORT_TAGS

  					cmd_free_tag(cmd);

  #else

  					hostdata->busy[cmd->device->id] &= ~(1 << cmd->device->lun);

  #endif

  					hostdata->connected = NULL;
  					cmd->result = DID_ERROR << 16;

  #ifdef NCR5380_STATS

  					collect_stats(hostdata, cmd);

  #endif

  					cmd->scsi_done(cmd);
  					NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
  					falcon_release_lock_if_possible(hostdata);
  					return;
  				}
  				msgout = NOP;
  				break;
  			case PHASE_CMDOUT:
  				len = cmd->cmd_len;
  				data = cmd->cmnd;
  				/*
  				 * XXX for performance reasons, on machines with a
  				 * PSEUDO-DMA architecture we should probably
  				 * use the dma transfer function.
  				 */
  				NCR5380_transfer_pio(instance, &phase, &len, &data);
  				break;
  			case PHASE_STATIN:
  				len = 1;
  				data = &tmp;
  				NCR5380_transfer_pio(instance, &phase, &len, &data);
  				cmd->SCp.Status = tmp;
  				break;
  			default:
  				printk("scsi%d: unknown phase
  ", HOSTNO);
  				NCR_PRINT(NDEBUG_ANY);
  			} /* switch(phase) */
  		} /* if (tmp * SR_REQ) */
  	} /* while (1) */

  }
  
  /*
   * Function : void NCR5380_reselect (struct Scsi_Host *instance)
   *

   * Purpose : does reselection, initializing the instance->connected
   *	field to point to the Scsi_Cmnd for which the I_T_L or I_T_L_Q

   *	nexus has been reestablished,

   *

   * Inputs : instance - this instance of the NCR5380.
   *
   */

  static void NCR5380_reselect(struct Scsi_Host *instance)

  {

  	SETUP_HOSTDATA(instance);
  	unsigned char target_mask;
  	unsigned char lun, phase;
  	int len;

  #ifdef SUPPORT_TAGS

  	unsigned char tag;

  #endif

  	unsigned char msg[3];
  	unsigned char *data;
  	Scsi_Cmnd *tmp = NULL, *prev;
  /*	unsigned long flags; */
  
  	/*
  	 * Disable arbitration, etc. since the host adapter obviously
  	 * lost, and tell an interrupted NCR5380_select() to restart.
  	 */
  
  	NCR5380_write(MODE_REG, MR_BASE);
  	hostdata->restart_select = 1;
  
  	target_mask = NCR5380_read(CURRENT_SCSI_DATA_REG) & ~(hostdata->id_mask);
  
  	RSL_PRINTK("scsi%d: reselect
  ", HOSTNO);
  
  	/*
  	 * At this point, we have detected that our SCSI ID is on the bus,
  	 * SEL is true and BSY was false for at least one bus settle delay
  	 * (400 ns).
  	 *
  	 * We must assert BSY ourselves, until the target drops the SEL
  	 * signal.
  	 */
  
  	NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_BSY);
  
  	while (NCR5380_read(STATUS_REG) & SR_SEL)
  		;
  	NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
  
  	/*
  	 * Wait for target to go into MSGIN.
  	 */
  
  	while (!(NCR5380_read(STATUS_REG) & SR_REQ))
  		;
  
  	len = 1;
  	data = msg;
  	phase = PHASE_MSGIN;
  	NCR5380_transfer_pio(instance, &phase, &len, &data);
  
  	if (!(msg[0] & 0x80)) {
  		printk(KERN_DEBUG "scsi%d: expecting IDENTIFY message, got ", HOSTNO);
  		spi_print_msg(msg);
  		do_abort(instance);
  		return;
  	}
  	lun = (msg[0] & 0x07);

  
  #ifdef SUPPORT_TAGS

  	/* If the phase is still MSGIN, the target wants to send some more
  	 * messages. In case it supports tagged queuing, this is probably a
  	 * SIMPLE_QUEUE_TAG for the I_T_L_Q nexus.
  	 */
  	tag = TAG_NONE;
  	if (phase == PHASE_MSGIN && setup_use_tagged_queuing) {
  		/* Accept previous IDENTIFY message by clearing ACK */
  		NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
  		len = 2;
  		data = msg + 1;
  		if (!NCR5380_transfer_pio(instance, &phase, &len, &data) &&
  		    msg[1] == SIMPLE_QUEUE_TAG)
  			tag = msg[2];
  		TAG_PRINTK("scsi%d: target mask %02x, lun %d sent tag %d at "
  			   "reselection
  ", HOSTNO, target_mask, lun, tag);
  	}

  #endif

  
  	/*
  	 * Find the command corresponding to the I_T_L or I_T_L_Q  nexus we
  	 * just reestablished, and remove it from the disconnected queue.
  	 */
  
  	for (tmp = (Scsi_Cmnd *) hostdata->disconnected_queue, prev = NULL;
  	     tmp; prev = tmp, tmp = NEXT(tmp)) {
  		if ((target_mask == (1 << tmp->device->id)) && (lun == tmp->device->lun)

  #ifdef SUPPORT_TAGS

  		    && (tag == tmp->tag)

  #endif

  		    ) {
  			/* ++guenther: prevent race with falcon_release_lock */
  			falcon_dont_release++;
  			if (prev) {
  				REMOVE(prev, NEXT(prev), tmp, NEXT(tmp));

  				SET_NEXT(prev, NEXT(tmp));

  			} else {
  				REMOVE(-1, hostdata->disconnected_queue, tmp, NEXT(tmp));
  				hostdata->disconnected_queue = NEXT(tmp);
  			}

  			SET_NEXT(tmp, NULL);

  			break;
  		}

  	}

  
  	if (!tmp) {
  		printk(KERN_WARNING "scsi%d: warning: target bitmask %02x lun %d "

  #ifdef SUPPORT_TAGS

  		       "tag %d "

  #endif

  		       "not in disconnected_queue.
  ",
  		       HOSTNO, target_mask, lun

  #ifdef SUPPORT_TAGS

  		       , tag

  #endif

  			);
  		/*
  		 * Since we have an established nexus that we can't do anything
  		 * with, we must abort it.
  		 */
  		do_abort(instance);
  		return;
  	}

  	/* Accept message by clearing ACK */
  	NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);

  	hostdata->connected = tmp;
  	RSL_PRINTK("scsi%d: nexus established, target = %d, lun = %d, tag = %d
  ",
  		   HOSTNO, tmp->device->id, tmp->device->lun, tmp->tag);
  	falcon_dont_release--;

  }
  
  
  /*
   * Function : int NCR5380_abort (Scsi_Cmnd *cmd)
   *
   * Purpose : abort a command
   *

   * Inputs : cmd - the Scsi_Cmnd to abort, code - code to set the
   *	host byte of the result field to, if zero DID_ABORTED is

   *	used.
   *
   * Returns : 0 - success, -1 on failure.
   *

   * XXX - there is no way to abort the command that is currently
   *	 connected, you have to wait for it to complete.  If this is

   *	 a problem, we could implement longjmp() / setjmp(), setjmp()

   *	 called where the loop started in NCR5380_main().

   */
  
  static

  int NCR5380_abort(Scsi_Cmnd *cmd)

  {

  	struct Scsi_Host *instance = cmd->device->host;
  	SETUP_HOSTDATA(instance);
  	Scsi_Cmnd *tmp, **prev;
  	unsigned long flags;

  	printk(KERN_NOTICE "scsi%d: aborting command
  ", HOSTNO);
  	scsi_print_command(cmd);

  	NCR5380_print_status(instance);
  
  	local_irq_save(flags);

  	if (!IS_A_TT() && !falcon_got_lock)
  		printk(KERN_ERR "scsi%d: !!BINGO!! Falcon has no lock in NCR5380_abort
  ",
  		       HOSTNO);

  	ABRT_PRINTK("scsi%d: abort called basr 0x%02x, sr 0x%02x
  ", HOSTNO,
  		    NCR5380_read(BUS_AND_STATUS_REG),
  		    NCR5380_read(STATUS_REG));

  
  #if 1

  	/*
  	 * Case 1 : If the command is the currently executing command,
  	 * we'll set the aborted flag and return control so that
  	 * information transfer routine can exit cleanly.
  	 */

  	if (hostdata->connected == cmd) {

  		ABRT_PRINTK("scsi%d: aborting connected command
  ", HOSTNO);
  		/*
  		 * We should perform BSY checking, and make sure we haven't slipped
  		 * into BUS FREE.
  		 */

  		/*	NCR5380_write(INITIATOR_COMMAND_REG, ICR_ASSERT_ATN); */
  		/*
  		 * Since we can't change phases until we've completed the current
  		 * handshake, we have to source or sink a byte of data if the current
  		 * phase is not MSGOUT.
  		 */

  		/*
  		 * Return control to the executing NCR drive so we can clear the
  		 * aborted flag and get back into our main loop.
  		 */

  		if (do_abort(instance) == 0) {
  			hostdata->aborted = 1;
  			hostdata->connected = NULL;
  			cmd->result = DID_ABORT << 16;

  #ifdef SUPPORT_TAGS

  			cmd_free_tag(cmd);

  #else

  			hostdata->busy[cmd->device->id] &= ~(1 << cmd->device->lun);

  #endif

  			local_irq_restore(flags);
  			cmd->scsi_done(cmd);
  			falcon_release_lock_if_possible(hostdata);
  			return SCSI_ABORT_SUCCESS;
  		} else {
  /*			local_irq_restore(flags); */
  			printk("scsi%d: abort of connected command failed!
  ", HOSTNO);
  			return SCSI_ABORT_ERROR;
  		}
  	}

  #endif

  	/*
  	 * Case 2 : If the command hasn't been issued yet, we simply remove it
  	 *	    from the issue queue.
  	 */
  	for (prev = (Scsi_Cmnd **)&(hostdata->issue_queue),
  	     tmp = (Scsi_Cmnd *)hostdata->issue_queue;
  	     tmp; prev = NEXTADDR(tmp), tmp = NEXT(tmp)) {
  		if (cmd == tmp) {
  			REMOVE(5, *prev, tmp, NEXT(tmp));
  			(*prev) = NEXT(tmp);

  			SET_NEXT(tmp, NULL);

  			tmp->result = DID_ABORT << 16;
  			local_irq_restore(flags);
  			ABRT_PRINTK("scsi%d: abort removed command from issue queue.
  ",
  				    HOSTNO);
  			/* Tagged queuing note: no tag to free here, hasn't been assigned
  			 * yet... */
  			tmp->scsi_done(tmp);
  			falcon_release_lock_if_possible(hostdata);
  			return SCSI_ABORT_SUCCESS;
  		}

  	}

  	/*
  	 * Case 3 : If any commands are connected, we're going to fail the abort
  	 *	    and let the high level SCSI driver retry at a later time or
  	 *	    issue a reset.
  	 *
  	 *	    Timeouts, and therefore aborted commands, will be highly unlikely
  	 *          and handling them cleanly in this situation would make the common
  	 *	    case of noresets less efficient, and would pollute our code.  So,
  	 *	    we fail.
  	 */

  	if (hostdata->connected) {
  		local_irq_restore(flags);
  		ABRT_PRINTK("scsi%d: abort failed, command connected.
  ", HOSTNO);
  		return SCSI_ABORT_SNOOZE;
  	}