Linux Cross Reference
Linux/drivers/scsi/mac_NCR5380.c

   /* 
    * 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.
   */
  
  /* 
   * Michael: To port Romans driver to the Macintosh, I've left most of the code 
   * unchanged, in order to make later implemantation of REAL_DMA easier. 
   *
   * Alan: In order to make it easier to read and as the 5380 based Mac's never
   *        have DMA I took the real DMA out of mac_scsi.c but not this file.
   *
   *      With luck we can merge this back with the ST folks in time.
   *
   * Changes:
   * 
   * - all Falcon-specific stuff (ST-DMA locking) was removed
   *
   * 
   */
  
  #if (NDEBUG & NDEBUG_LISTS)
  #define LIST(x,y) \
    { printk("LINE:%d   Adding %p to %p\n", __LINE__, (void*)(x), (void*)(y)); \
      if ((x)==(y)) udelay(5); }
  #define REMOVE(w,x,y,z) \
    { printk("LINE:%d   Removing: %p->%p  %p->%p \n", __LINE__, \
             (void*)(w), (void*)(x), (void*)(y), (void*)(z)); \
     if ((x)==(y)) udelay(5); }
 #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 a 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.
  *
  * PSEUDO_DMA - if defined, PSEUDO DMA is used during the data transfer phases.
  *
  * 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 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 NEXTADDR(cmd)   ((Scsi_Cmnd **)&((cmd)->host_scribble))
 
 #define HOSTNO          instance->host_no
 #define H_NO(cmd)       (cmd)->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
 
 /* For the m68k, the number of bits in 'allocated' must be a multiple of 32! */
 #if (MAX_TAGS % 32) != 0
 #error "MAX_TAGS must be a multiple of 32!"
 #endif
 
 typedef struct {
     char        allocated[MAX_TAGS/8];
     int         nr_allocated;
     int         queue_size;
 } TAG_ALLOC;
 
 static TAG_ALLOC TagAlloc[8][8]; /* 8 targets and 8 LUNs */
 
 
 static void 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];
             memset( &ta->allocated, 0, MAX_TAGS/8 );
             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->host);
 
     if (hostdata->busy[cmd->target] & (1 << cmd->lun))
         return( 1 );
     if (!should_be_tagged ||
         !setup_use_tagged_queuing || !cmd->device->tagged_supported)
         return( 0 );
     if (TagAlloc[cmd->target][cmd->lun].nr_allocated >=
         TagAlloc[cmd->target][cmd->lun].queue_size ) {
         TAG_PRINTK( "scsi%d: target %d lun %d: no free tags\n",
                     H_NO(cmd), cmd->target, cmd->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->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->target] |= (1 << cmd->lun);
         TAG_PRINTK( "scsi%d: target %d lun %d now allocated by untagged "
                     "command\n", H_NO(cmd), cmd->target, cmd->lun );
     }
     else {
         TAG_ALLOC *ta = &TagAlloc[cmd->target][cmd->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)\n",
                     H_NO(cmd), cmd->tag, cmd->target, cmd->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->host);
 
     if (cmd->tag == TAG_NONE) {
         hostdata->busy[cmd->target] &= ~(1 << cmd->lun);
         TAG_PRINTK( "scsi%d: target %d lun %d untagged cmd finished\n",
                     H_NO(cmd), cmd->target, cmd->lun );
     }
     else if (cmd->tag >= MAX_TAGS) {
         printk(KERN_NOTICE "scsi%d: trying to free bad tag %d!\n",
                 H_NO(cmd), cmd->tag );
     }
     else {
         TAG_ALLOC *ta = &TagAlloc[cmd->target][cmd->lun];
         clear_bit( cmd->tag, &ta->allocated );
         ta->nr_allocated--;
         TAG_PRINTK( "scsi%d: freed tag %d for target %d lun %d\n",
                     H_NO(cmd), cmd->tag, cmd->target, cmd->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];
             memset( &ta->allocated, 0, MAX_TAGS/8 );
             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 transfered 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(cmd->SCp.buffer[1].address) == endaddr; ) {
         
         MER_PRINTK("VTOP(%p) == %08lx -> merging\n",
                    cmd->SCp.buffer[1].address, 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\n",
                    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 (cmd->use_sg) {
         cmd->SCp.buffer = (struct scatterlist *) cmd->buffer;
         cmd->SCp.buffers_residual = cmd->use_sg - 1;
         cmd->SCp.ptr = (char *) cmd->SCp.buffer->address;
         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 = (char *) cmd->request_buffer;
         cmd->SCp.this_residual = cmd->request_bufflen;
     }
 }
 
 #include <linux/config.h>
 #include <linux/delay.h>
 
 #if 1
 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;
 
     save_flags(flags);
     cli();
     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);
     restore_flags(flags);
     printk("STATUS_REG: %02x ", status);
     for (i = 0; signals[i].mask ; ++i) 
         if (status & signals[i].mask)
             printk(",%s", signals[i].name);
     printk("\nBASR: %02x ", basr);
     for (i = 0; basrs[i].mask ; ++i) 
         if (basr & basrs[i].mask)
             printk(",%s", basrs[i].name);
     printk("\nICR: %02x ", icr);
     for (i = 0; icrs[i].mask; ++i) 
         if (icr & icrs[i].mask)
             printk(",%s", icrs[i].name);
     printk("\nMODE: %02x ", mr);
     for (i = 0; mrs[i].mask; ++i) 
         if (mr & mrs[i].mask)
             printk(",%s", mrs[i].name);
     printk("\n");
 }
 
 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.\n", HOSTNO);
     else {
         for (i = 0; (phases[i].value != PHASE_UNKNOWN) && 
             (phases[i].value != (status & PHASE_MASK)); ++i); 
         printk(KERN_DEBUG "scsi%d: phase %s\n", HOSTNO, phases[i].name);
     }
 }
 
 #else /* !NDEBUG */
 
 /* dummies... */
 __inline__ void NCR5380_print(struct Scsi_Host *instance) { };
 __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/tqueue.h>
 #include <linux/interrupt.h>
 
 static volatile int main_running = 0;
 static struct tq_struct NCR5380_tqueue = {
     NULL,               /* next */
     0,                  /* sync */
     (void (*)(void*))NCR5380_main,  /* routine, must have (void *) arg... */
     NULL                /* data */
 };
 
 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. */
         queue_task(&NCR5380_tqueue, &tq_immediate);
         mark_bh(IMMEDIATE_BH);
     }
     /* else: nothing to do: the running NCR5380_main() will pick up
        any newly queued command. */
 }
 
 
 static void NCR5380_all_init (void)
 {
     static int done = 0;
     if (!done) {
         INI_PRINTK("scsi : NCR5380_all_init()\n");
         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 NCR5380_print_options (struct Scsi_Host *instance)
 {
     printk(" generic options"
 #ifdef AUTOSENSE 
     " AUTOSENSE"
 #endif
 #ifdef REAL_DMA
     " REAL DMA"
 #endif
 #ifdef PSEUDO_DMA
     " PSEUDO 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\n");
         return;
     }
     len = NCR5380_proc_info(pr_bfr, &start, 0, PAGE_SIZE, HOSTNO, 0);
     pr_bfr[len] = 0;
     printk("\n%s\n", 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);
 
 #ifndef NCR5380_proc_info
 static
 #endif
 int NCR5380_proc_info (char *buffer, char **start, off_t offset,
                        int length, int hostno, int inout)
 {
     char *pos = buffer;
     struct Scsi_Host *instance;
     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)
 
     for (instance = first_instance; instance && HOSTNO != hostno;
          instance = instance->next)
         ;
     if (!instance)
         return(-ESRCH);
     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.\n", NCR5380_PUBLIC_RELEASE);
     check_offset();
     save_flags(flags);
     cli();
     SPRINTF("NCR5380: coroutine is%s running.\n", main_running ? "" : "n't");
     check_offset();
     if (!hostdata->connected)
         SPRINTF("scsi%d: no currently connected command\n", HOSTNO);
     else
         pos = lprint_Scsi_Cmnd ((Scsi_Cmnd *) hostdata->connected,
                                 pos, buffer, length);
     SPRINTF("scsi%d: issue_queue\n", 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\n", HOSTNO);
     check_offset();
     for (ptr = (Scsi_Cmnd *) hostdata->disconnected_queue; ptr;
          ptr = NEXT(ptr)) {
         pos = lprint_Scsi_Cmnd (ptr, pos, buffer, length);
         check_offset();
     }
 
     restore_flags(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\n",
             H_NO(cmd), cmd->target, cmd->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("\n");
     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 void 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\n"
                 "        without AUTOSENSE option, contingent allegiance conditions may\n"
                 "        be incorrectly cleared.\n", 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);
 }
 
 /* 
  * 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.
  *
  */
 
 /* Only make static if a wrapper function is used */
 #ifndef NCR5380_queue_command
 static
 #endif
 int NCR5380_queue_command (Scsi_Cmnd *cmd, void (*done)(Scsi_Cmnd *))
 {
     SETUP_HOSTDATA(cmd->host);
     Scsi_Cmnd *tmp;
     int oldto;
     unsigned long flags;
     extern int update_timeout(Scsi_Cmnd * SCset, int timeout);
 
 #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\n",
                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 (cmd->request_bufflen > NCR5380_STAT_LIMIT)
 # endif
         switch (cmd->cmnd[0])
         {
             case WRITE:
             case WRITE_6:
             case WRITE_10:
                 hostdata->time_write[cmd->target] -= (jiffies - hostdata->timebase);
                 hostdata->bytes_write[cmd->target] += cmd->request_bufflen;
                 hostdata->pendingw++;
                 break;
             case READ:
             case READ_6:
             case READ_10:
                 hostdata->time_read[cmd->target] -= (jiffies - hostdata->timebase);
                 hostdata->bytes_read[cmd->target] += cmd->request_bufflen;
                 hostdata->pendingr++;
                 break;
         }
 #endif
 
     /* 
      * We use the host_scribble field as a pointer to the next command  
      * in a queue 
      */
 
     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.
      */
 
     save_flags(flags);
     cli();
 
     if (!(hostdata->issue_queue) || (cmd->cmnd[0] == REQUEST_SENSE)) {
         LIST(cmd, hostdata->issue_queue);
         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);
         NEXT(tmp) = cmd;
     }
     restore_flags(flags);
 
     QU_PRINTK("scsi%d: command added to %s of queue\n", 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() > 0 || ((flags >> 8) & 7) >= 6)
         queue_main();
     else
         NCR5380_main();
     return 0;
 }
 
 /*
  * 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 (void)
 {
     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;
 
     save_flags(flags);
     do {
         cli(); /* Freeze request queues */
         done = 1;
         
         if (!hostdata->connected) {
             MAIN_PRINTK( "scsi%d: not connected\n", 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\n");/* else printk("\n");*/
 #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\n",
                            tmp, tmp->target, hostdata->busy[tmp->target],
                            tmp->lun);
 #endif
                 /*  When we find one, remove it from the issue queue. */
                 if (
 #ifdef SUPPORT_TAGS
                     !is_lun_busy( tmp, tmp->cmnd[0] != REQUEST_SENSE)
 #else
                     !(hostdata->busy[tmp->target] & (1 << tmp->lun))
 #endif
                     ) {
                     cli(); /* ++guenther: just to be sure, this must be atomic */
                     if (prev) {
                         REMOVE(prev, NEXT(prev), tmp, NEXT(tmp));
                         NEXT(prev) = NEXT(tmp);
                     } else {
                         REMOVE(-1, hostdata->issue_queue, tmp, NEXT(tmp));
                         hostdata->issue_queue = NEXT(tmp);
                     }
                     NEXT(tmp) = NULL;
                     
                     /* reenable interrupts after finding one */
                     restore_flags(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\n",
                                 HOSTNO, tmp->target, tmp->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)) {
                         break;
                     } else {
                         cli();
                         LIST(tmp, hostdata->issue_queue);
                         NEXT(tmp) = hostdata->issue_queue;
                         hostdata->issue_queue = tmp;
 #ifdef SUPPORT_TAGS
                         cmd_free_tag( tmp );
 #endif
                         restore_flags(flags);
                         MAIN_PRINTK("scsi%d: main(): select() failed, "
                                     "returned to issue_queue\n", 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
             ) {
             restore_flags(flags);
             MAIN_PRINTK("scsi%d: main: performing information transfer\n",
                         HOSTNO);
             NCR5380_information_transfer(instance);
             MAIN_PRINTK("scsi%d: main: done set false\n", 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;
     restore_flags(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\n", HOSTNO);
         return;
     }
     
     if (mac_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\n", HOSTNO);
             }
         }
     }
 
     DMA_PRINTK("scsi%d: real DMA transfer complete, basr 0x%X, sr 0x%X\n",
                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 (mac_read_overruns) {
         if ((NCR5380_read(STATUS_REG) & PHASE_MASK) == p && (p & SR_IO)) {
             cnt = toPIO = mac_read_overruns;
             if (overrun) {
                 DMA_PRINTK("Got an input overrun, using saved byte\n");
                 *(*data)++ = saved_data;
                 (*count)--;
                 cnt--;
                 toPIO--;
             }
             DMA_PRINTK("Doing %d-byte PIO to 0x%08lx\n", 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 void NCR5380_intr (int irq, void *dev_id, struct pt_regs *regs)
 {
     struct Scsi_Host *instance = first_instance;
     int done = 1;
     unsigned char basr;
 
     INT_PRINTK("scsi%d: NCR5380 irq triggered\n", HOSTNO);
 
     /* Look for pending interrupts */
     basr = NCR5380_read(BUS_AND_STATUS_REG);
     INT_PRINTK("scsi%d: BASR=%02x\n", 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\n", HOSTNO);
             NCR5380_reselect(instance);
             (void) NCR5380_read(RESET_PARITY_INTERRUPT_REG);
         }
         else if (basr & BASR_PARITY_ERROR) {
             INT_PRINTK("scsi%d: PARITY interrupt\n", HOSTNO);
             (void) NCR5380_read(RESET_PARITY_INTERRUPT_REG);
         }
         else if ((NCR5380_read(STATUS_REG) & SR_RST) == SR_RST) {
             INT_PRINTK("scsi%d: RESET interrupt\n", 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\n", 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\n",
                            HOSTNO, basr, NCR5380_read(MODE_REG),
                            NCR5380_read(STATUS_REG));
                 (void) NCR5380_read(RESET_PARITY_INTERRUPT_REG);
             }
         } /* if !(SELECTION || PARITY) */
     } /* BASR & IRQ */
     else {
         printk(KERN_NOTICE "scsi%d: interrupt without IRQ bit set in BASR, "
                "BASR 0x%X, MR 0x%X, SR 0x%x\n", 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\n", HOSTNO);
         /* Put a call to NCR5380_main() on the queue... */
         queue_main();
     }
 }
 
 #ifdef NCR5380_STATS
 static void collect_stats(struct NCR5380_hostdata* hostdata, Scsi_Cmnd* cmd)
 {
 # ifdef NCR5380_STAT_LIMIT
     if (cmd->request_bufflen > NCR5380_STAT_LIMIT)
 # endif
         switch (cmd->cmnd[0])
         {
             case WRITE:
             case WRITE_6:
             case WRITE_10:
                 hostdata->time_write[cmd->target] += (jiffies - hostdata->timebase);
                 /*hostdata->bytes_write[cmd->target] += cmd->request_bufflen;*/
                 hostdata->pendingw--;
                 break;
             case READ:
             case READ_6:
             case READ_10:
                 hostdata->time_read[cmd->target] += (jiffies - hostdata->timebase);
                 /*hostdata->bytes_read[cmd->target] += cmd->request_bufflen;*/
                 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\n", HOSTNO,
                instance->this_id);
 
     /* 
      * Set the phase bits to 0, otherwise the NCR5380 won't drive the 
      * data bus during SELECTION.
      */
 
     save_flags(flags);
     cli();
     if (hostdata->connected) {
         restore_flags(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);
 
     restore_flags(flags);
 
     /* Wait for arbitration logic to complete */
 #if 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\n", __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\n", 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\n",
                    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\n",
                    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\n", 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->target)));
 
     /* 
      * 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\n", HOSTNO, cmd->target);
 
     /* 
      * 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?\n",
                     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->target)) {
             printk(KERN_ERR "scsi%d: weirdness\n", HOSTNO);
             if (hostdata->restart_select)
                 printk(KERN_NOTICE "\trestart select\n");
             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\n", HOSTNO);
         NCR5380_write(SELECT_ENABLE_REG, hostdata->id_mask);
         return 0;
     } 
 
     hostdata->targets_present |= (1 << cmd->target);
 
     /*
      * 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.\n",
                HOSTNO, cmd->target);
     tmp[0] = IDENTIFY(1, cmd->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.\n", HOSTNO);
     /* XXX need to handle errors here */
     hostdata->connected = cmd;
 #ifndef SUPPORT_TAGS
     hostdata->busy[cmd->target] |= (1 << cmd->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 transfered 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\n", HOSTNO);
 
         /* Check for phase mismatch */  
         if ((tmp & PHASE_MASK) != p) {
             PIO_PRINTK("scsi%d: phase mismatch\n", 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\n", 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\n", 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) || defined(PSEUDO_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 transfered 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;
     register int foo;
     unsigned char tmp;
     unsigned long flags;
 
 
     if ((tmp = (NCR5380_read(STATUS_REG) & PHASE_MASK)) != p) {
         *phase = tmp;
         return -1;
     }
 
     if (mac_read_overruns && (p & SR_IO)) {
         c -= mac_read_overruns;
     }
 
     DMA_PRINTK("scsi%d: initializing DMA for %s, %d bytes %s %p\n",
                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);
 #else /* PSEUDO_DMA! */
 #if defined(PSEUDO_DMA) && !defined(UNSAFE)
     save_flags(flags);
     cli();
 #endif
     /* KLL May need eop and parity in 53c400 */
     if (hostdata->flags & FLAG_NCR53C400)
         NCR5380_write(MODE_REG, MR_BASE | MR_DMA_MODE | MR_ENABLE_PAR_CHECK
         | MR_ENABLE_PAR_INTR | MR_ENABLE_EOP_INTR | MR_DMA_MODE
         | MR_MONITOR_BSY);
     else
 #ifndef EMULATE_PSEUDO_DMA
         NCR5380_write(MODE_REG, MR_BASE | MR_DMA_MODE);
 #else
         NCR5380_write(MODE_REG, MR_BASE);
 #endif
 #endif /* def REAL_DMA  */
 
 #ifdef REAL_DMA
     /* On the Medusa, it is a must to initialize the DMA before
      * starting the NCR. This is also the cleaner way for the TT.
      */
     save_flags(flags);
     cli();
     hostdata->dma_len = (p & SR_IO) ?
         NCR5380_dma_read_setup(instance, d, c) : 
         NCR5380_dma_write_setup(instance, d, c);
     restore_flags(flags);
 #endif /* def REAL_DMA */
 
 #ifndef EMULATE_PSEUDO_DMA
     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);
     }
 #else
     hostdata->dma_len = c;
 #endif
 
 #if defined(REAL_DMA)
     return 0;
 #else /* defined(PSEUDO_DMA) */
     if (p & SR_IO) {
 #ifdef DMA_WORKS_RIGHT
         foo = NCR5380_pread(instance, d, c);
 #else
         int diff = 1;
         if (hostdata->flags & FLAG_NCR53C400) {
             diff=0;
         }
 
         if (!(foo = NCR5380_pread(instance, d, c - diff))) {
             /*
              * We can't disable DMA mode after successfully transferring 
              * what we plan to be the last byte, since that would open up
              * a race condition where if the target asserted REQ before 
              * we got the DMA mode reset, the NCR5380 would have latched
              * an additional byte into the INPUT DATA register and we'd
              * have dropped it.
              * 
              * The workaround was to transfer one fewer bytes than we 
              * intended to with the pseudo-DMA read function, wait for 
              * the chip to latch the last byte, read it, and then disable
              * pseudo-DMA mode.
              * 
              * After REQ is asserted, the NCR5380 asserts DRQ and ACK.
              * REQ is deasserted when ACK is asserted, and not reasserted
              * until ACK goes false.  Since the NCR5380 won't lower ACK
              * until DACK is asserted, which won't happen unless we twiddle
              * the DMA port or we take the NCR5380 out of DMA mode, we 
              * can guarantee that we won't handshake another extra 
              * byte.
              */
 
             if (!(hostdata->flags & FLAG_NCR53C400)) {
                 while (!(NCR5380_read(BUS_AND_STATUS_REG) & BASR_DRQ));
                 /* Wait for clean handshake */
                 while (NCR5380_read(STATUS_REG) & SR_REQ);
                 d[c - 1] = NCR5380_read(INPUT_DATA_REG);
             }
         }
 #endif
     } else {
 #ifdef DMA_WORKS_RIGHT
         foo = NCR5380_pwrite(instance, d, c);
 #else
         int timeout;
 #if (NDEBUG & NDEBUG_C400_PWRITE)
         printk("About to pwrite %d bytes\n", c);
 #endif
         if (!(foo = NCR5380_pwrite(instance, d, c))) {
             /*
              * Wait for the last byte to be sent.  If REQ is being asserted for 
              * the byte we're interested, we'll ACK it and it will go false.  
              */
             if (!(hostdata->flags & FLAG_HAS_LAST_BYTE_SENT)) {
                 timeout = 20000;
 #if 1
 #if 1
                 while (!(NCR5380_read(BUS_AND_STATUS_REG) & 
                         BASR_DRQ) && (NCR5380_read(BUS_AND_STATUS_REG) &
                         BASR_PHASE_MATCH));
 #else
                 if (NCR5380_read(STATUS_REG) & SR_REQ) {
                     for (; timeout && 
                         !(NCR5380_read(BUS_AND_STATUS_REG) & BASR_ACK); 
                         --timeout);
                     for (; timeout && (NCR5380_read(STATUS_REG) & SR_REQ);
                         --timeout);
                 } 
 #endif
         
 
 #if (NDEBUG & NDEBUG_LAST_BYTE_SENT)
                 if (!timeout) 
                     printk("scsi%d : timed out on last byte\n",
                             instance->host_no);
 #endif
 
 
                 if (hostdata->flags & FLAG_CHECK_LAST_BYTE_SENT) {
                     hostdata->flags &= ~FLAG_CHECK_LAST_BYTE_SENT;
                     if (NCR5380_read(TARGET_COMMAND_REG) & TCR_LAST_BYTE_SENT) {
                         hostdata->flags |= FLAG_HAS_LAST_BYTE_SENT;
 #if (NDEBUG & NDEBUG_LAST_BYTE_SENT)
                         printk("scsi%d : last bit sent works\n", 
                             instance->host_no);
 #endif
                     }
                 }
             } else  {
 #if (NDEBUG & NDEBUG_C400_PWRITE)
                 printk("Waiting for LASTBYTE\n");
 #endif
                 while (!(NCR5380_read(TARGET_COMMAND_REG) & TCR_LAST_BYTE_SENT));
 #if (NDEBUG & NDEBUG_C400_PWRITE)
                 printk("Got LASTBYTE\n");
 #endif
             }
 #else
             udelay (5);
 #endif
         }
 #endif
     }
 
     NCR5380_write(MODE_REG, MR_BASE);
     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
 
     if ((!(p & SR_IO)) && (hostdata->flags & FLAG_NCR53C400)) {
 #if (NDEBUG & NDEBUG_C400_PWRITE)
         printk("53C400w: Checking for IRQ\n");
 #endif
         if (NCR5380_read(BUS_AND_STATUS_REG) & BASR_IRQ) {
 #if (NDEBUG & NDEBUG_C400_PWRITE)
             printk("53C400w:    got it, reading reset interrupt reg\n");
 #endif
             NCR5380_read(RESET_PARITY_INTERRUPT_REG);
         } else {
             printk("53C400w:    IRQ NOT THERE!\n");
         }
     }
 
     *data = d + c;
     *count = 0;
     *phase = NCR5380_read(STATUS_REG) & PHASE_MASK;
 #if 0
     NCR5380_print_phase(instance);
 #endif
 #if defined(PSEUDO_DMA) && !defined(UNSAFE)
     restore_flags(flags);
 #endif /* defined(REAL_DMA_POLL) */
     return foo;
 #endif /* def REAL_DMA */
 }
 #endif /* defined(REAL_DMA) || defined(PSEUDO_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(PSEUDO_DMA) || defined(REAL_DMA_POLL)
     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\n", HOSTNO);
                 sink = 1;
                 do_abort(instance);
                 cmd->result = DID_ERROR  << 16;
                 cmd->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 = cmd->SCp.buffer->address;
                     /* ++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\n",
                                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) || defined(PSEUDO_DMA)
                 if (!cmd->device->borken &&
                     !(hostdata->flags & FLAG_NO_PSEUDO_DMA) &&
                     (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\n", HOSTNO,
                                cmd->target, cmd->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->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                   
                         /* Michael: When using pseudo-DMA emulation, we must 
                          * take care to take into account the residual from 
                          * the current transfer as determined by either the 
                          * interrupt routine ot the pseudo-transfer functions
                          * (whichever notices it first).
                          */
                         if (mac_pdma_residual)
                           len -= mac_pdma_residual;
                         cmd->SCp.this_residual -= transfersize - len;
 #endif
                     }
                 } else
 #endif /* defined(REAL_DMA) || defined(PSEUDO_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.\n", HOSTNO, cmd->target, cmd->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\n",
                                 HOSTNO, cmd->target, cmd->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().\n",
                                HOSTNO, cmd->target, cmd->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);
                     hostdata->connected = NULL;
                     QU_PRINTK("scsi%d: command for target %d, lun %d "
                               "completed\n", HOSTNO, cmd->target, cmd->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->target][cmd->lun];
                         TAG_PRINTK("scsi%d: target %d lun %d returned "
                                    "QUEUE_FULL after %d commands\n",
                                    HOSTNO, cmd->target, cmd->lun,
                                    ta->nr_allocated);
                         if (ta->queue_size > ta->nr_allocated)
                             ta->nr_allocated = ta->queue_size;
                     }
 #else
                     hostdata->busy[cmd->target] &= ~(1 << cmd->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) && 
                         (status_byte(cmd->SCp.Status) == CHECK_CONDITION)) {
                         ASEN_PRINTK("scsi%d: performing request sense\n",
                                     HOSTNO);
                         cmd->cmnd[0] = REQUEST_SENSE;
                         cmd->cmnd[1] &= 0xe0;
                         cmd->cmnd[2] = 0;
                         cmd->cmnd[3] = 0;
                         cmd->cmnd[4] = sizeof(cmd->sense_buffer);
                         cmd->cmnd[5] = 0;
                         cmd->cmd_len = COMMAND_SIZE(cmd->cmnd[0]);
 
                         cmd->use_sg = 0;
                         /* this is initialized from initialize_SCp 
                         cmd->SCp.buffer = NULL;
                         cmd->SCp.buffers_residual = 0;
                         */
                         cmd->request_buffer = (char *) cmd->sense_buffer;
                         cmd->request_bufflen = sizeof(cmd->sense_buffer);
 
                         save_flags(flags);
                         cli();
                         LIST(cmd,hostdata->issue_queue);
                         NEXT(cmd) = hostdata->issue_queue;
                         hostdata->issue_queue = (Scsi_Cmnd *) cmd;
                         restore_flags(flags);
                         QU_PRINTK("scsi%d: REQUEST SENSE added to head of "
                                   "issue queue\n", 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();
 
                     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->target] |= (1 << cmd->lun);
                         cmd->tag = TAG_NONE;
                         TAG_PRINTK("scsi%d: target %d lun %d rejected "
                                    "QUEUE_TAG message; tagged queuing "
                                    "disabled\n",
                                    HOSTNO, cmd->target, cmd->lun);
                         break;
                     }
                     break;
                 case DISCONNECT:
                     /* Accept message by clearing ACK */
                     NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
                     save_flags(flags);
                     cli();
                     cmd->device->disconnect = 1;
                     LIST(cmd,hostdata->disconnected_queue);
                     NEXT(cmd) = hostdata->disconnected_queue;
                     hostdata->connected = NULL;
                     hostdata->disconnected_queue = cmd;
                     restore_flags(flags);
                     QU_PRINTK("scsi%d: command for target %d lun %d was "
                               "moved from connected to the "
                               "disconnected_queue\n", HOSTNO, 
                               cmd->target, cmd->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 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\n", 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\n", 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\n",
                                    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\n", HOSTNO);
                         tmp = 0;
                     } else {
                         printk(KERN_NOTICE "scsi%d: extended message "
                                "code %02x length %d is too long\n",
                                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);
                         print_msg (extended_msg);
                         printk("\n");
                     } else if (tmp != EXTENDED_MESSAGE)
                         printk(KERN_DEBUG "scsi%d: rejecting unknown "
                                "message %02x from target %d, lun %d\n",
                                HOSTNO, tmp, cmd->target, cmd->lun);
                     else
                         printk(KERN_DEBUG "scsi%d: rejecting unknown "
                                "extended message "
                                "code %02x, length %d from target %d, lun %d\n",
                                HOSTNO, extended_msg[1], extended_msg[0],
                                cmd->target, cmd->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->target] &= ~(1 << cmd->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);
                     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\n", 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\n", 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);
         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\n", 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->target)) && (lun == tmp->lun)
 #ifdef SUPPORT_TAGS
             && (tag == tmp->tag) 
 #endif
             ) {
             if (prev) {
                 REMOVE(prev, NEXT(prev), tmp, NEXT(tmp));
                 NEXT(prev) = NEXT(tmp);
             } else {
                 REMOVE(-1, hostdata->disconnected_queue, tmp, NEXT(tmp));
                 hostdata->disconnected_queue = NEXT(tmp);
             }
             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 disconnect_queue.\n",
                 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\n",
                HOSTNO, tmp->target, tmp->lun, tmp->tag);
 }
 
 
 /*
  * 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().
  */
 
 #ifndef NCR5380_abort
 static
 #endif
 int NCR5380_abort (Scsi_Cmnd *cmd)
 {
     struct Scsi_Host *instance = cmd->host;
     SETUP_HOSTDATA(instance);
     Scsi_Cmnd *tmp, **prev;
     unsigned long flags;
 
     printk(KERN_NOTICE "scsi%d: aborting command\n", HOSTNO);
     print_Scsi_Cmnd (cmd);
 
     NCR5380_print_status (instance);
 
     save_flags(flags);
     cli();
     
     ABRT_PRINTK("scsi%d: abort called basr 0x%02x, sr 0x%02x\n", 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\n", 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->target] &= ~(1 << cmd->lun);
 #endif
           restore_flags(flags);
           cmd->scsi_done(cmd);
           return SCSI_ABORT_SUCCESS;
         } else {
 /*        restore_flags(flags); */
           printk("scsi%d: abort of connected command failed!\n", 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);
             NEXT(tmp) = NULL;
             tmp->result = DID_ABORT << 16;
             restore_flags(flags);
             ABRT_PRINTK("scsi%d: abort removed command from issue queue.\n",
                         HOSTNO);
             /* Tagged queuing note: no tag to free here, hasn't been assigned
              * yet... */
             tmp->scsi_done(tmp);
             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) {
         restore_flags(flags);
         ABRT_PRINTK("scsi%d: abort failed, command connected.\n", HOSTNO);
         return SCSI_ABORT_SNOOZE;
     }
 
 /*
  * Case 4: If the command is currently disconnected from the bus, and 
  *      there are no connected commands, we reconnect the I_T_L or 
  *      I_T_L_Q nexus associated with it, go into message out, and send 
  *      an abort message.
  *
  * This case is especially ugly. In order to reestablish the nexus, we
  * need to call NCR5380_select().  The easiest way to implement this 
  * function was to abort if the bus was busy, and let the interrupt
  * handler triggered on the SEL for reselect take care of lost arbitrations
  * where necessary, meaning interrupts need to be enabled.
  *
  * When interrupts are enabled, the queues may change - so we 
  * can't remove it from the disconnected queue before selecting it
  * because that could cause a failure in hashing the nexus if that 
  * device reselected.
  * 
  * Since the queues may change, we can't use the pointers from when we
  * first locate it.
  *
  * So, we must first locate the command, and if NCR5380_select()
  * succeeds, then issue the abort, relocate the command and remove
  * it from the disconnected queue.
  */
 
     for (tmp = (Scsi_Cmnd *) hostdata->disconnected_queue; tmp;
          tmp = NEXT(tmp)) 
         if (cmd == tmp) {
             restore_flags(flags);
             ABRT_PRINTK("scsi%d: aborting disconnected command.\n", HOSTNO);
   
             if (NCR5380_select (instance, cmd, (int) cmd->tag)) 
                 return SCSI_ABORT_BUSY;
 
             ABRT_PRINTK("scsi%d: nexus reestablished.\n", HOSTNO);
 
             do_abort (instance);
 
             save_flags(flags);
             cli();
             for (prev = (Scsi_Cmnd **) &(hostdata->disconnected_queue), 
                 tmp = (Scsi_Cmnd *) hostdata->disconnected_queue;
                 tmp; prev = NEXTADDR(tmp), tmp = NEXT(tmp) )
                     if (cmd == tmp) {
                     REMOVE(5, *prev, tmp, NEXT(tmp));
                     *prev = NEXT(tmp);
                     NEXT(tmp) = NULL;
                     tmp->result = DID_ABORT << 16;
                     /* We must unlock the tag/LUN immediately here, since the
                      * target goes to BUS FREE and doesn't send us another
                      * message (COMMAND_COMPLETE or the like)
                      */
 #ifdef SUPPORT_TAGS
                     cmd_free_tag( tmp );
 #else
                     hostdata->busy[cmd->target] &= ~(1 << cmd->lun);
 #endif
                     restore_flags(flags);
                     tmp->scsi_done(tmp);
                     return SCSI_ABORT_SUCCESS;
                 }
         }
 
 /*
  * Case 5 : If we reached this point, the command was not found in any of 
  *          the queues.
  *
  * We probably reached this point because of an unlikely race condition
  * between the command completing successfully and the abortion code,
  * so we won't panic, but we will notify the user in case something really
  * broke.
  */
 
     restore_flags(flags);
     printk(KERN_INFO "scsi%d: warning : SCSI command probably completed successfully\n"
            KERN_INFO "        before abortion\n", HOSTNO); 
 
 /* Maybe it is sufficient just to release the ST-DMA lock... (if
  * possible at all) At least, we should check if the lock could be
  * released after the abort, in case it is kept due to some bug.
  */
 
     return SCSI_ABORT_NOT_RUNNING;
 }
 
 
 /* 
  * Function : int NCR5380_reset (Scsi_Cmnd *cmd, unsigned int reset_flags)
  * 
  * Purpose : reset the SCSI bus.
  *
  * Returns : SCSI_RESET_WAKEUP
  *
  */ 
 
 static int NCR5380_reset( Scsi_Cmnd *cmd, unsigned int reset_flags)
 {
     SETUP_HOSTDATA(cmd->host);
     int           i;
     unsigned long flags;
 #if 1
     Scsi_Cmnd *connected, *disconnected_queue;
 #endif
 
     NCR5380_print_status (cmd->host);
 
     /* get in phase */
     NCR5380_write( TARGET_COMMAND_REG,
                    PHASE_SR_TO_TCR( NCR5380_read(STATUS_REG) ));
     /* assert RST */
     NCR5380_write( INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_RST );
     udelay (40);
     /* reset NCR registers */
     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 );
     /* ++roman: reset interrupt condition! otherwise no interrupts don't get
      * through anymore ... */
     (void)NCR5380_read( RESET_PARITY_INTERRUPT_REG );
 
 #if 1 /* XXX Should now be done by midlevel code, but it's broken XXX */
       /* XXX see below                                            XXX */
 
     /* MSch: old-style reset: actually abort all command processing here */
 
     /* After the reset, there are no more connected or disconnected commands
      * and no busy units; to avoid problems with re-inserting the commands
      * into the issue_queue (via scsi_done()), the aborted commands are
      * remembered in local variables first.
      */
     save_flags(flags);
     cli();
     connected = (Scsi_Cmnd *)hostdata->connected;
     hostdata->connected = NULL;
     disconnected_queue = (Scsi_Cmnd *)hostdata->disconnected_queue;
     hostdata->disconnected_queue = NULL;
 #ifdef SUPPORT_TAGS
     free_all_tags();
 #endif
     for( i = 0; i < 8; ++i )
         hostdata->busy[i] = 0;
 #ifdef REAL_DMA
     hostdata->dma_len = 0;
 #endif
     restore_flags(flags);
 
     /* In order to tell the mid-level code which commands were aborted, 
      * set the command status to DID_RESET and call scsi_done() !!!
      * This ultimately aborts processing of these commands in the mid-level.
      */
 
     if ((cmd = connected)) {
         ABRT_PRINTK("scsi%d: reset aborted a connected command\n", H_NO(cmd));
         cmd->result = (cmd->result & 0xffff) | (DID_RESET << 16);
         cmd->scsi_done( cmd );
     }
 
     for (i = 0; (cmd = disconnected_queue); ++i) {
         disconnected_queue = NEXT(cmd);
         NEXT(cmd) = NULL;
         cmd->result = (cmd->result & 0xffff) | (DID_RESET << 16);
         cmd->scsi_done( cmd );
     }
     if (i > 0)
         ABRT_PRINTK("scsi: reset aborted %d disconnected command(s)\n", i);
 
     /* since all commands have been explicitly terminated, we need to tell
      * the midlevel code that the reset was SUCCESSFUL, and there is no 
      * need to 'wake up' the commands by a request_sense
      */
     return SCSI_RESET_SUCCESS | SCSI_RESET_BUS_RESET;
 #else /* 1 */
 
     /* MSch: new-style reset handling: let the mid-level do what it can */
 
     /* ++guenther: MID-LEVEL IS STILL BROKEN.
      * Mid-level is supposed to requeue all commands that were active on the
      * various low-level queues. In fact it does this, but that's not enough
      * because all these commands are subject to timeout. And if a timeout
      * happens for any removed command, *_abort() is called but all queues
      * are now empty. Abort then gives up the falcon lock, which is fatal,
      * since the mid-level will queue more commands and must have the lock
      * (it's all happening inside timer interrupt handler!!).
      * Even worse, abort will return NOT_RUNNING for all those commands not
      * on any queue, so they won't be retried ...
      *
      * Conclusion: either scsi.c disables timeout for all resetted commands
      * immediately, or we loose!  As of linux-2.0.20 it doesn't.
      */
 
     /* After the reset, there are no more connected or disconnected commands
      * and no busy units; so clear the low-level status here to avoid 
      * conflicts when the mid-level code tries to wake up the affected 
      * commands!
      */
 
     if (hostdata->issue_queue)
         ABRT_PRINTK("scsi%d: reset aborted issued command(s)\n", H_NO(cmd));
     if (hostdata->connected) 
         ABRT_PRINTK("scsi%d: reset aborted a connected command\n", H_NO(cmd));
     if (hostdata->disconnected_queue)
         ABRT_PRINTK("scsi%d: reset aborted disconnected command(s)\n", H_NO(cmd));
 
     save_flags(flags);
     cli();
     hostdata->issue_queue = NULL;
     hostdata->connected = NULL;
     hostdata->disconnected_queue = NULL;
 #ifdef SUPPORT_TAGS
     free_all_tags();
 #endif
     for( i = 0; i < 8; ++i )
         hostdata->busy[i] = 0;
 #ifdef REAL_DMA
     hostdata->dma_len = 0;
 #endif
     restore_flags(flags);
 
     /* we did no complete reset of all commands, so a wakeup is required */
     return SCSI_RESET_WAKEUP | SCSI_RESET_BUS_RESET;
 #endif /* 1 */
 }
 
 static Scsi_Host_Template driver_template = MAC_NCR5380;
 
 #include "scsi_module.c"
 
 /* Local Variables: */
 /* tab-width: 8     */
 /* End:             */