xref: /asus-wl-520gu-7.0.1.45/src/linux/linux/drivers/scsi/wd33c93.c

/*
 *    wd33c93.c - Linux-68k device driver for the Commodore
 *                Amiga A2091/590 SCSI controller card
 *
 * Copyright (c) 1996 John Shifflett, GeoLog Consulting
 *    john@geolog.com
 *    jshiffle@netcom.com
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 *
 * Drew Eckhardt's excellent 'Generic NCR5380' sources from Linux-PC
 * provided much of the inspiration and some of the code for this
 * driver. Everything I know about Amiga DMA was gleaned from careful
 * reading of Hamish Mcdonald's original wd33c93 driver; in fact, I
 * borrowed shamelessly from all over that source. Thanks Hamish!
 *
 * _This_ driver is (I feel) an improvement over the old one in
 * several respects:
 *
 *    -  Target Disconnection/Reconnection  is now supported. Any
 *          system with more than one device active on the SCSI bus
 *          will benefit from this. The driver defaults to what I
 *          call 'adaptive disconnect' - meaning that each command
 *          is evaluated individually as to whether or not it should
 *          be run with the option to disconnect/reselect (if the
 *          device chooses), or as a "SCSI-bus-hog".
 *
 *    -  Synchronous data transfers are now supported. Because of
 *          a few devices that choke after telling the driver that
 *          they can do sync transfers, we don't automatically use
 *          this faster protocol - it can be enabled via the command-
 *          line on a device-by-device basis.
 *
 *    -  Runtime operating parameters can now be specified through
 *       the 'amiboot' or the 'insmod' command line. For amiboot do:
 *          "amiboot [usual stuff] wd33c93=blah,blah,blah"
 *       The defaults should be good for most people. See the comment
 *       for 'setup_strings' below for more details.
 *
 *    -  The old driver relied exclusively on what the Western Digital
 *          docs call "Combination Level 2 Commands", which are a great
 *          idea in that the CPU is relieved of a lot of interrupt
 *          overhead. However, by accepting a certain (user-settable)
 *          amount of additional interrupts, this driver achieves
 *          better control over the SCSI bus, and data transfers are
 *          almost as fast while being much easier to define, track,
 *          and debug.
 *
 *
 * TODO:
 *       more speed. linked commands.
 *
 *
 * People with bug reports, wish-lists, complaints, comments,
 * or improvements are asked to pah-leeez email me (John Shifflett)
 * at john@geolog.com or jshiffle@netcom.com! I'm anxious to get
 * this thing into as good a shape as possible, and I'm positive
 * there are lots of lurking bugs and "Stupid Places".
 *
 * Updates:
 *
 * Added support for pre -A chips, which don't have advanced features
 * and will generate CSR_RESEL rather than CSR_RESEL_AM.
 *	Richard Hirst <richard@sleepie.demon.co.uk>  August 2000
 */

#include <linux/config.h>
#include <linux/module.h>

#include <asm/system.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/delay.h>
#include <linux/version.h>
#include <linux/init.h>
#include <asm/irq.h>
#include <linux/blk.h>

#include "scsi.h"
#include "hosts.h"


#define WD33C93_VERSION    "1.25"
#define WD33C93_DATE       "09/Jul/1997"
/* NOTE: 1.25 for m68k is related to in2000-1.31 for x86 */

/*
 * Note - the following defines have been moved to 'wd33c93.h':
 *
 *    PROC_INTERFACE
 *    PROC_STATISTICS
 *    SYNC_DEBUG
 *    DEBUGGING_ON
 *    DEBUG_DEFAULTS
 *
 */


#include "wd33c93.h"



/*
 * 'setup_strings' is a single string used to pass operating parameters and
 * settings from the kernel/module command-line to the driver. 'setup_args[]'
 * is an array of strings that define the compile-time default values for
 * these settings. If Linux boots with an amiboot or insmod command-line,
 * those settings are combined with 'setup_args[]'. Note that amiboot
 * command-lines are prefixed with "wd33c93=" while insmod uses a
 * "setup_strings=" prefix. The driver recognizes the following keywords
 * (lower case required) and arguments:
 *
 * -  nosync:bitmask -bitmask is a byte where the 1st 7 bits correspond with
 *                    the 7 possible SCSI devices. Set a bit to negotiate for
 *                    asynchronous transfers on that device. To maintain
 *                    backwards compatibility, a command-line such as
 *                    "wd33c93=255" will be automatically translated to
 *                    "wd33c93=nosync:0xff".
 * -  nodma:x        -x = 1 to disable DMA, x = 0 to enable it. Argument is
 *                    optional - if not present, same as "nodma:1".
 * -  period:ns      -ns is the minimum # of nanoseconds in a SCSI data transfer
 *                    period. Default is 500; acceptable values are 250 - 1000.
 * -  disconnect:x   -x = 0 to never allow disconnects, 2 to always allow them.
 *                    x = 1 does 'adaptive' disconnects, which is the default
 *                    and generally the best choice.
 * -  debug:x        -If 'DEBUGGING_ON' is defined, x is a bit mask that causes
 *                    various types of debug output to printed - see the DB_xxx
 *                    defines in wd33c93.h
 * -  clock:x        -x = clock input in MHz for WD33c93 chip. Normal values
 *                    would be from 8 through 20. Default is 8.
 * -  next           -No argument. Used to separate blocks of keywords when
 *                    there's more than one host adapter in the system.
 *
 * Syntax Notes:
 * -  Numeric arguments can be decimal or the '0x' form of hex notation. There
 *    _must_ be a colon between a keyword and its numeric argument, with no
 *    spaces.
 * -  Keywords are separated by commas, no spaces, in the standard kernel
 *    command-line manner.
 * -  A keyword in the 'nth' comma-separated command-line member will overwrite
 *    the 'nth' element of setup_args[]. A blank command-line member (in
 *    other words, a comma with no preceding keyword) will _not_ overwrite
 *    the corresponding setup_args[] element.
 * -  If a keyword is used more than once, the first one applies to the first
 *    SCSI host found, the second to the second card, etc, unless the 'next'
 *    keyword is used to change the order.
 *
 * Some amiboot examples (for insmod, use 'setup_strings' instead of 'wd33c93'):
 * -  wd33c93=nosync:255
 * -  wd33c93=nodma
 * -  wd33c93=nodma:1
 * -  wd33c93=disconnect:2,nosync:0x08,period:250
 * -  wd33c93=debug:0x1c
 */

/* Normally, no defaults are specified */
static char *setup_args[] =
      {"","","","","","","","",""};

/* filled in by 'insmod' */
static char *setup_strings = 0;

#ifdef MODULE_PARM
MODULE_PARM(setup_strings, "s");
#endif



static inline uchar read_wd33c93(const wd33c93_regs regs, uchar reg_num)
{
   *regs.SASR = reg_num;
   mb();
   return(*regs.SCMD);
}


#define READ_AUX_STAT() (*regs.SASR)


static inline void write_wd33c93(const wd33c93_regs regs, uchar reg_num,
				 uchar value)
{
   *regs.SASR = reg_num;
   mb();
   *regs.SCMD = value;
   mb();
}


static inline void write_wd33c93_cmd(const wd33c93_regs regs, uchar cmd)
{
   *regs.SASR = WD_COMMAND;
   mb();
   *regs.SCMD = cmd;
   mb();
}


static inline uchar read_1_byte(const wd33c93_regs regs)
{
uchar asr;
uchar x = 0;

   write_wd33c93(regs, WD_CONTROL, CTRL_IDI | CTRL_EDI | CTRL_POLLED);
   write_wd33c93_cmd(regs, WD_CMD_TRANS_INFO|0x80);
   do {
      asr = READ_AUX_STAT();
      if (asr & ASR_DBR)
         x = read_wd33c93(regs, WD_DATA);
      } while (!(asr & ASR_INT));
   return x;
}


static void write_wd33c93_count(const wd33c93_regs regs, unsigned long value)
{
   *regs.SASR = WD_TRANSFER_COUNT_MSB;
   mb();
   *regs.SCMD = value >> 16;
   *regs.SCMD = value >> 8;
   *regs.SCMD = value;
   mb();
}


static unsigned long read_wd33c93_count(const wd33c93_regs regs)
{
unsigned long value;

   *regs.SASR = WD_TRANSFER_COUNT_MSB;
   mb();
   value = *regs.SCMD << 16;
   value |= *regs.SCMD << 8;
   value |= *regs.SCMD;
   mb();
   return value;
}


/* The 33c93 needs to be told which direction a command transfers its
 * data; we use this function to figure it out. Returns true if there
 * will be a DATA_OUT phase with this command, false otherwise.
 * (Thanks to Joerg Dorchain for the research and suggestion.)
 */
static int is_dir_out(Scsi_Cmnd *cmd)
{
   switch (cmd->cmnd[0]) {
      case WRITE_6:           case WRITE_10:          case WRITE_12:
      case WRITE_LONG:        case WRITE_SAME:        case WRITE_BUFFER:
      case WRITE_VERIFY:      case WRITE_VERIFY_12:
      case COMPARE:           case COPY:              case COPY_VERIFY:
      case SEARCH_EQUAL:      case SEARCH_HIGH:       case SEARCH_LOW:
      case SEARCH_EQUAL_12:   case SEARCH_HIGH_12:    case SEARCH_LOW_12:
      case FORMAT_UNIT:       case REASSIGN_BLOCKS:   case RESERVE:
      case MODE_SELECT:       case MODE_SELECT_10:    case LOG_SELECT:
      case SEND_DIAGNOSTIC:   case CHANGE_DEFINITION: case UPDATE_BLOCK:
      case SET_WINDOW:        case MEDIUM_SCAN:       case SEND_VOLUME_TAG:
      case 0xea:
         return 1;
      default:
         return 0;
      }
}



static struct sx_period sx_table[] = {
   {  1, 0x20},
   {252, 0x20},
   {376, 0x30},
   {500, 0x40},
   {624, 0x50},
   {752, 0x60},
   {876, 0x70},
   {1000,0x00},
   {0,   0} };

static int round_period(unsigned int period)
{
int x;

   for (x=1; sx_table[x].period_ns; x++) {
      if ((period <= sx_table[x-0].period_ns) &&
          (period >  sx_table[x-1].period_ns)) {
         return x;
         }
      }
   return 7;
}

static uchar calc_sync_xfer(unsigned int period, unsigned int offset)
{
uchar result;

   period *= 4;   /* convert SDTR code to ns */
   result = sx_table[round_period(period)].reg_value;
   result |= (offset < OPTIMUM_SX_OFF)?offset:OPTIMUM_SX_OFF;
   return result;
}



static void wd33c93_execute(struct Scsi_Host *instance);

int wd33c93_queuecommand (Scsi_Cmnd *cmd, void (*done)(Scsi_Cmnd *))
{
   struct WD33C93_hostdata *hostdata;
   Scsi_Cmnd *tmp;
   unsigned long flags;

   hostdata = (struct WD33C93_hostdata *)cmd->host->hostdata;

DB(DB_QUEUE_COMMAND,printk("Q-%d-%02x-%ld( ",cmd->target,cmd->cmnd[0],cmd->pid))

/* Set up a few fields in the Scsi_Cmnd structure for our own use:
 *  - host_scribble is the pointer to the next cmd in the input queue
 *  - scsi_done points to the routine we call when a cmd is finished
 *  - result is what you'd expect
 */

   cmd->host_scribble = NULL;
   cmd->scsi_done = done;
   cmd->result = 0;


   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;
      }
   else {
      cmd->SCp.buffer = NULL;
      cmd->SCp.buffers_residual = 0;
      cmd->SCp.ptr = (char *)cmd->request_buffer;
      cmd->SCp.this_residual = cmd->request_bufflen;
      }

/* WD docs state that at the conclusion of a "LEVEL2" command, the
 * status byte can be retrieved from the LUN register. Apparently,
 * this is the case only for *uninterrupted* LEVEL2 commands! If
 * there are any unexpected phases entered, even if they are 100%
 * legal (different devices may choose to do things differently),
 * the LEVEL2 command sequence is exited. This often occurs prior
 * to receiving the status byte, in which case the driver does a
 * status phase interrupt and gets the status byte on its own.
 * While such a command can then be "resumed" (ie restarted to
 * finish up as a LEVEL2 command), the LUN register will NOT be
 * a valid status byte at the command's conclusion, and we must
 * use the byte obtained during the earlier interrupt. Here, we
 * preset SCp.Status to an illegal value (0xff) so that when
 * this command finally completes, we can tell where the actual
 * status byte is stored.
 */

   cmd->SCp.Status = ILLEGAL_STATUS_BYTE;

   /*
    * Add the cmd to the end of 'input_Q'. Note that REQUEST SENSE
    * commands are added to the head of the queue so that the desired
    * sense data is not lost before REQUEST_SENSE executes.
    */

   save_flags(flags);
   cli();

   if (!(hostdata->input_Q) || (cmd->cmnd[0] == REQUEST_SENSE)) {
      cmd->host_scribble = (uchar *)hostdata->input_Q;
      hostdata->input_Q = cmd;
      }
   else {   /* find the end of the queue */
      for (tmp=(Scsi_Cmnd *)hostdata->input_Q; tmp->host_scribble;
            tmp=(Scsi_Cmnd *)tmp->host_scribble)
         ;
      tmp->host_scribble = (uchar *)cmd;
      }

/* We know that there's at least one command in 'input_Q' now.
 * Go see if any of them are runnable!
 */

   wd33c93_execute(cmd->host);

DB(DB_QUEUE_COMMAND,printk(")Q-%ld ",cmd->pid))

   restore_flags(flags);
   return 0;
}



/*
 * This routine attempts to start a scsi command. If the host_card is
 * already connected, we give up immediately. Otherwise, look through
 * the input_Q, using the first command we find that's intended
 * for a currently non-busy target/lun.
 *
 * wd33c93_execute() is always called with interrupts disabled or from
 * the wd33c93_intr itself, which means that a wd33c93 interrupt
 * cannot occur while we are in here.
 */
static void wd33c93_execute (struct Scsi_Host *instance)
{
struct WD33C93_hostdata *hostdata = (struct WD33C93_hostdata *)instance->hostdata;
const wd33c93_regs regs = hostdata->regs;
Scsi_Cmnd *cmd, *prev;
int i;

DB(DB_EXECUTE,printk("EX("))

   if (hostdata->selecting || hostdata->connected) {

DB(DB_EXECUTE,printk(")EX-0 "))

      return;
      }

    /*
     * Search through the input_Q for a command destined
     * for an idle target/lun.
     */

   cmd = (Scsi_Cmnd *)hostdata->input_Q;
   prev = 0;
   while (cmd) {
      if (!(hostdata->busy[cmd->target] & (1 << cmd->lun)))
         break;
      prev = cmd;
      cmd = (Scsi_Cmnd *)cmd->host_scribble;
      }

   /* quit if queue empty or all possible targets are busy */

   if (!cmd) {

DB(DB_EXECUTE,printk(")EX-1 "))

      return;
      }

   /*  remove command from queue */

   if (prev)
      prev->host_scribble = cmd->host_scribble;
   else
      hostdata->input_Q = (Scsi_Cmnd *)cmd->host_scribble;

#ifdef PROC_STATISTICS
   hostdata->cmd_cnt[cmd->target]++;
#endif

   /*
    * Start the selection process
    */

   if (is_dir_out(cmd))
      write_wd33c93(regs, WD_DESTINATION_ID, cmd->target);
   else
      write_wd33c93(regs, WD_DESTINATION_ID, cmd->target | DSTID_DPD);

/* Now we need to figure out whether or not this command is a good
 * candidate for disconnect/reselect. We guess to the best of our
 * ability, based on a set of hierarchical rules. When several
 * devices are operating simultaneously, disconnects are usually
 * an advantage. In a single device system, or if only 1 device
 * is being accessed, transfers usually go faster if disconnects
 * are not allowed:
 *
 * + Commands should NEVER disconnect if hostdata->disconnect =
 *   DIS_NEVER (this holds for tape drives also), and ALWAYS
 *   disconnect if hostdata->disconnect = DIS_ALWAYS.
 * + Tape drive commands should always be allowed to disconnect.
 * + Disconnect should be allowed if disconnected_Q isn't empty.
 * + Commands should NOT disconnect if input_Q is empty.
 * + Disconnect should be allowed if there are commands in input_Q
 *   for a different target/lun. In this case, the other commands
 *   should be made disconnect-able, if not already.
 *
 * I know, I know - this code would flunk me out of any
 * "C Programming 101" class ever offered. But it's easy
 * to change around and experiment with for now.
 */

   cmd->SCp.phase = 0;  /* assume no disconnect */
   if (hostdata->disconnect == DIS_NEVER)
      goto no;
   if (hostdata->disconnect == DIS_ALWAYS)
      goto yes;
   if (cmd->device->type == 1)   /* tape drive? */
      goto yes;
   if (hostdata->disconnected_Q) /* other commands disconnected? */
      goto yes;
   if (!(hostdata->input_Q))     /* input_Q empty? */
      goto no;
   for (prev=(Scsi_Cmnd *)hostdata->input_Q; prev;
         prev=(Scsi_Cmnd *)prev->host_scribble) {
      if ((prev->target != cmd->target) || (prev->lun != cmd->lun)) {
         for (prev=(Scsi_Cmnd *)hostdata->input_Q; prev;
               prev=(Scsi_Cmnd *)prev->host_scribble)
            prev->SCp.phase = 1;
         goto yes;
         }
      }
   goto no;

yes:
   cmd->SCp.phase = 1;

#ifdef PROC_STATISTICS
   hostdata->disc_allowed_cnt[cmd->target]++;
#endif

no:

   write_wd33c93(regs, WD_SOURCE_ID, ((cmd->SCp.phase)?SRCID_ER:0));

   write_wd33c93(regs, WD_TARGET_LUN, cmd->lun);
   write_wd33c93(regs, WD_SYNCHRONOUS_TRANSFER,hostdata->sync_xfer[cmd->target]);
   hostdata->busy[cmd->target] |= (1 << cmd->lun);

   if ((hostdata->level2 == L2_NONE) ||
       (hostdata->sync_stat[cmd->target] == SS_UNSET)) {

         /*
          * Do a 'Select-With-ATN' command. This will end with
          * one of the following interrupts:
          *    CSR_RESEL_AM:  failure - can try again later.
          *    CSR_TIMEOUT:   failure - give up.
          *    CSR_SELECT:    success - proceed.
          */

      hostdata->selecting = cmd;

/* Every target has its own synchronous transfer setting, kept in the
 * sync_xfer array, and a corresponding status byte in sync_stat[].
 * Each target's sync_stat[] entry is initialized to SX_UNSET, and its
 * sync_xfer[] entry is initialized to the default/safe value. SS_UNSET
 * means that the parameters are undetermined as yet, and that we
 * need to send an SDTR message to this device after selection is
 * complete: We set SS_FIRST to tell the interrupt routine to do so.
 * If we've been asked not to try synchronous transfers on this
 * target (and _all_ luns within it), we'll still send the SDTR message
 * later, but at that time we'll negotiate for async by specifying a
 * sync fifo depth of 0.
 */
      if (hostdata->sync_stat[cmd->target] == SS_UNSET)
            hostdata->sync_stat[cmd->target] = SS_FIRST;
      hostdata->state = S_SELECTING;
      write_wd33c93_count(regs, 0); /* guarantee a DATA_PHASE interrupt */
      write_wd33c93_cmd(regs, WD_CMD_SEL_ATN);
      }

   else {

         /*
          * Do a 'Select-With-ATN-Xfer' command. This will end with
          * one of the following interrupts:
          *    CSR_RESEL_AM:  failure - can try again later.
          *    CSR_TIMEOUT:   failure - give up.
          *    anything else: success - proceed.
          */

      hostdata->connected = cmd;
      write_wd33c93(regs, WD_COMMAND_PHASE, 0);

   /* copy command_descriptor_block into WD chip
    * (take advantage of auto-incrementing)
    */

      *regs.SASR = WD_CDB_1;
      for (i=0; i<cmd->cmd_len; i++)
         *regs.SCMD = cmd->cmnd[i];

   /* The wd33c93 only knows about Group 0, 1, and 5 commands when
    * it's doing a 'select-and-transfer'. To be safe, we write the
    * size of the CDB into the OWN_ID register for every case. This
    * way there won't be problems with vendor-unique, audio, etc.
    */

      write_wd33c93(regs, WD_OWN_ID, cmd->cmd_len);

   /* When doing a non-disconnect command with DMA, we can save
    * ourselves a DATA phase interrupt later by setting everything
    * up ahead of time.
    */

      if ((cmd->SCp.phase == 0) && (hostdata->no_dma == 0)) {
         if (hostdata->dma_setup(cmd,
                     (is_dir_out(cmd))?DATA_OUT_DIR:DATA_IN_DIR))
            write_wd33c93_count(regs, 0); /* guarantee a DATA_PHASE interrupt */
         else {
            write_wd33c93_count(regs, cmd->SCp.this_residual);
            write_wd33c93(regs, WD_CONTROL, CTRL_IDI | CTRL_EDI | CTRL_DMA);
            hostdata->dma = D_DMA_RUNNING;
            }
         }
      else
         write_wd33c93_count(regs, 0); /* guarantee a DATA_PHASE interrupt */

      hostdata->state = S_RUNNING_LEVEL2;
      write_wd33c93_cmd(regs, WD_CMD_SEL_ATN_XFER);
      }

   /*
    * Since the SCSI bus can handle only 1 connection at a time,
    * we get out of here now. If the selection fails, or when
    * the command disconnects, we'll come back to this routine
    * to search the input_Q again...
    */

DB(DB_EXECUTE,printk("%s%ld)EX-2 ",(cmd->SCp.phase)?"d:":"",cmd->pid))
}



static void transfer_pio(const wd33c93_regs regs, uchar *buf, int cnt,
			 int data_in_dir, struct WD33C93_hostdata *hostdata)
{
uchar asr;

DB(DB_TRANSFER,printk("(%p,%d,%s:",buf,cnt,data_in_dir?"in":"out"))

   write_wd33c93(regs, WD_CONTROL, CTRL_IDI | CTRL_EDI | CTRL_POLLED);
   write_wd33c93_count(regs, cnt);
   write_wd33c93_cmd(regs, WD_CMD_TRANS_INFO);
   if (data_in_dir) {
      do {
         asr = READ_AUX_STAT();
         if (asr & ASR_DBR)
            *buf++ = read_wd33c93(regs, WD_DATA);
         } while (!(asr & ASR_INT));
      }
   else {
      do {
         asr = READ_AUX_STAT();
         if (asr & ASR_DBR)
            write_wd33c93(regs, WD_DATA, *buf++);
         } while (!(asr & ASR_INT));
      }

   /* Note: we are returning with the interrupt UN-cleared.
   * Since (presumably) an entire I/O operation has
   * completed, the bus phase is probably different, and
   * the interrupt routine will discover this when it
   * responds to the uncleared int.
   */

}



static void transfer_bytes(const wd33c93_regs regs, Scsi_Cmnd *cmd,
			   int data_in_dir)
{
struct WD33C93_hostdata *hostdata;
unsigned long length;

   hostdata = (struct WD33C93_hostdata *)cmd->host->hostdata;

/* Normally, you'd expect 'this_residual' to be non-zero here.
 * In a series of scatter-gather transfers, however, this
 * routine will usually be called with 'this_residual' equal
 * to 0 and 'buffers_residual' non-zero. This means that a
 * previous transfer completed, clearing 'this_residual', and
 * now we need to setup the next scatter-gather buffer as the
 * source or destination for THIS transfer.
 */
   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;
      }

   write_wd33c93(regs, WD_SYNCHRONOUS_TRANSFER,hostdata->sync_xfer[cmd->target]);

/* 'hostdata->no_dma' is TRUE if we don't even want to try DMA.
 * Update 'this_residual' and 'ptr' after 'transfer_pio()' returns.
 */

   if (hostdata->no_dma)
      goto use_transfer_pio;

/* 'dma_setup()' will return TRUE if we can't do DMA.
 * Update 'this_residual' and 'ptr' after 'transfer_pio()' returns.
 */

   else if (hostdata->dma_setup(cmd, data_in_dir)) {
use_transfer_pio:
#ifdef PROC_STATISTICS
      hostdata->pio_cnt++;
#endif
      transfer_pio(regs, (uchar *)cmd->SCp.ptr, cmd->SCp.this_residual,
                         data_in_dir, hostdata);
      length = cmd->SCp.this_residual;
      cmd->SCp.this_residual = read_wd33c93_count(regs);
      cmd->SCp.ptr += (length - cmd->SCp.this_residual);
      }

/* We are able to do DMA (in fact, the Amiga hardware is
 * already going!), so start up the wd33c93 in DMA mode.
 * We set 'hostdata->dma' = D_DMA_RUNNING so that when the
 * transfer completes and causes an interrupt, we're
 * reminded to tell the Amiga to shut down its end. We'll
 * postpone the updating of 'this_residual' and 'ptr'
 * until then.
 */

   else {
#ifdef PROC_STATISTICS
      hostdata->dma_cnt++;
#endif
      write_wd33c93(regs, WD_CONTROL, CTRL_IDI | CTRL_EDI | CTRL_DMA);
      write_wd33c93_count(regs, cmd->SCp.this_residual);

      if ((hostdata->level2 >= L2_DATA) ||
          (hostdata->level2 == L2_BASIC && cmd->SCp.phase == 0)) {
         write_wd33c93(regs, WD_COMMAND_PHASE, 0x45);
         write_wd33c93_cmd(regs, WD_CMD_SEL_ATN_XFER);
         hostdata->state = S_RUNNING_LEVEL2;
         }
      else
         write_wd33c93_cmd(regs, WD_CMD_TRANS_INFO);

      hostdata->dma = D_DMA_RUNNING;
      }
}



void wd33c93_intr (struct Scsi_Host *instance)
{
struct WD33C93_hostdata *hostdata = (struct WD33C93_hostdata *)instance->hostdata;
const wd33c93_regs regs = hostdata->regs;
Scsi_Cmnd *patch, *cmd;
uchar asr, sr, phs, id, lun, *ucp, msg;
unsigned long length, flags;

   asr = READ_AUX_STAT();
   if (!(asr & ASR_INT) || (asr & ASR_BSY))
      return;

   save_flags(flags);

#ifdef PROC_STATISTICS
   hostdata->int_cnt++;
#endif

   cmd = (Scsi_Cmnd *)hostdata->connected;   /* assume we're connected */
   sr = read_wd33c93(regs, WD_SCSI_STATUS);  /* clear the interrupt */
   phs = read_wd33c93(regs, WD_COMMAND_PHASE);

DB(DB_INTR,printk("{%02x:%02x-",asr,sr))

/* After starting a DMA transfer, the next interrupt
 * is guaranteed to be in response to completion of
 * the transfer. Since the Amiga DMA hardware runs in
 * in an open-ended fashion, it needs to be told when
 * to stop; do that here if D_DMA_RUNNING is true.
 * Also, we have to update 'this_residual' and 'ptr'
 * based on the contents of the TRANSFER_COUNT register,
 * in case the device decided to do an intermediate
 * disconnect (a device may do this if it has to do a
 * seek, or just to be nice and let other devices have
 * some bus time during long transfers). After doing
 * whatever is needed, we go on and service the WD3393
 * interrupt normally.
 */

   if (hostdata->dma == D_DMA_RUNNING) {
DB(DB_TRANSFER,printk("[%p/%d:",cmd->SCp.ptr,cmd->SCp.this_residual))
      hostdata->dma_stop(cmd->host, cmd, 1);
      hostdata->dma = D_DMA_OFF;
      length = cmd->SCp.this_residual;
      cmd->SCp.this_residual = read_wd33c93_count(regs);
      cmd->SCp.ptr += (length - cmd->SCp.this_residual);
DB(DB_TRANSFER,printk("%p/%d]",cmd->SCp.ptr,cmd->SCp.this_residual))
      }

/* Respond to the specific WD3393 interrupt - there are quite a few! */

   switch (sr) {

      case CSR_TIMEOUT:
DB(DB_INTR,printk("TIMEOUT"))

         if (hostdata->state == S_RUNNING_LEVEL2)
            hostdata->connected = NULL;
         else {
            cmd = (Scsi_Cmnd *)hostdata->selecting;   /* get a valid cmd */
            hostdata->selecting = NULL;
            }

         cmd->result = DID_NO_CONNECT << 16;
         hostdata->busy[cmd->target] &= ~(1 << cmd->lun);
         hostdata->state = S_UNCONNECTED;
         cmd->scsi_done(cmd);

    /* From esp.c:
     * There is a window of time within the scsi_done() path
     * of execution where interrupts are turned back on full
     * blast and left that way.  During that time we could
     * reconnect to a disconnected command, then we'd bomb
     * out below.  We could also end up executing two commands
     * at _once_.  ...just so you know why the restore_flags()
     * is here...
     */

    restore_flags(flags);

/* We are not connected to a target - check to see if there
 * are commands waiting to be executed.
 */

         wd33c93_execute(instance);
         break;


/* Note: this interrupt should not occur in a LEVEL2 command */

      case CSR_SELECT:

DB(DB_INTR,printk("SELECT"))
         hostdata->connected = cmd = (Scsi_Cmnd *)hostdata->selecting;
         hostdata->selecting = NULL;

      /* construct an IDENTIFY message with correct disconnect bit */

         hostdata->outgoing_msg[0] = (0x80 | 0x00 | cmd->lun);
         if (cmd->SCp.phase)
            hostdata->outgoing_msg[0] |= 0x40;

         if (hostdata->sync_stat[cmd->target] == SS_FIRST) {
#ifdef SYNC_DEBUG
printk(" sending SDTR ");
#endif

            hostdata->sync_stat[cmd->target] = SS_WAITING;

/* Tack on a 2nd message to ask about synchronous transfers. If we've
 * been asked to do only asynchronous transfers on this device, we
 * request a fifo depth of 0, which is equivalent to async - should
 * solve the problems some people have had with GVP's Guru ROM.
 */

            hostdata->outgoing_msg[1] = EXTENDED_MESSAGE;
            hostdata->outgoing_msg[2] = 3;
            hostdata->outgoing_msg[3] = EXTENDED_SDTR;
            if (hostdata->no_sync & (1 << cmd->target)) {
               hostdata->outgoing_msg[4] = hostdata->default_sx_per/4;
               hostdata->outgoing_msg[5] = 0;
               }
            else {
            hostdata->outgoing_msg[4] = OPTIMUM_SX_PER/4;
            hostdata->outgoing_msg[5] = OPTIMUM_SX_OFF;
               }
            hostdata->outgoing_len = 6;
            }
         else
            hostdata->outgoing_len = 1;

         hostdata->state = S_CONNECTED;
         break;


      case CSR_XFER_DONE|PHS_DATA_IN:
      case CSR_UNEXP    |PHS_DATA_IN:
      case CSR_SRV_REQ  |PHS_DATA_IN:
DB(DB_INTR,printk("IN-%d.%d",cmd->SCp.this_residual,cmd->SCp.buffers_residual))
         transfer_bytes(regs, cmd, DATA_IN_DIR);
         if (hostdata->state != S_RUNNING_LEVEL2)
            hostdata->state = S_CONNECTED;
         break;


      case CSR_XFER_DONE|PHS_DATA_OUT:
      case CSR_UNEXP    |PHS_DATA_OUT:
      case CSR_SRV_REQ  |PHS_DATA_OUT:
DB(DB_INTR,printk("OUT-%d.%d",cmd->SCp.this_residual,cmd->SCp.buffers_residual))
         transfer_bytes(regs, cmd, DATA_OUT_DIR);
         if (hostdata->state != S_RUNNING_LEVEL2)
            hostdata->state = S_CONNECTED;
         break;


/* Note: this interrupt should not occur in a LEVEL2 command */

      case CSR_XFER_DONE|PHS_COMMAND:
      case CSR_UNEXP    |PHS_COMMAND:
      case CSR_SRV_REQ  |PHS_COMMAND:
DB(DB_INTR,printk("CMND-%02x,%ld",cmd->cmnd[0],cmd->pid))
         transfer_pio(regs, cmd->cmnd, cmd->cmd_len, DATA_OUT_DIR, hostdata);
         hostdata->state = S_CONNECTED;
         break;


      case CSR_XFER_DONE|PHS_STATUS:
      case CSR_UNEXP    |PHS_STATUS:
      case CSR_SRV_REQ  |PHS_STATUS:
DB(DB_INTR,printk("STATUS="))

         cmd->SCp.Status = read_1_byte(regs);
DB(DB_INTR,printk("%02x",cmd->SCp.Status))
         if (hostdata->level2 >= L2_BASIC) {
            sr = read_wd33c93(regs, WD_SCSI_STATUS);  /* clear interrupt */
            hostdata->state = S_RUNNING_LEVEL2;
            write_wd33c93(regs, WD_COMMAND_PHASE, 0x50);
            write_wd33c93_cmd(regs, WD_CMD_SEL_ATN_XFER);
            }
         else {
            hostdata->state = S_CONNECTED;
            }
         break;


      case CSR_XFER_DONE|PHS_MESS_IN:
      case CSR_UNEXP    |PHS_MESS_IN:
      case CSR_SRV_REQ  |PHS_MESS_IN:
DB(DB_INTR,printk("MSG_IN="))

         msg = read_1_byte(regs);
         sr = read_wd33c93(regs, WD_SCSI_STATUS);  /* clear interrupt */

         hostdata->incoming_msg[hostdata->incoming_ptr] = msg;
         if (hostdata->incoming_msg[0] == EXTENDED_MESSAGE)
            msg = EXTENDED_MESSAGE;
         else
            hostdata->incoming_ptr = 0;

         cmd->SCp.Message = msg;
         switch (msg) {

            case COMMAND_COMPLETE:
DB(DB_INTR,printk("CCMP-%ld",cmd->pid))
               write_wd33c93_cmd(regs, WD_CMD_NEGATE_ACK);
               hostdata->state = S_PRE_CMP_DISC;
               break;

            case SAVE_POINTERS:
DB(DB_INTR,printk("SDP"))
               write_wd33c93_cmd(regs, WD_CMD_NEGATE_ACK);
               hostdata->state = S_CONNECTED;
               break;

            case RESTORE_POINTERS:
DB(DB_INTR,printk("RDP"))
               if (hostdata->level2 >= L2_BASIC) {
                  write_wd33c93(regs, WD_COMMAND_PHASE, 0x45);
                  write_wd33c93_cmd(regs, WD_CMD_SEL_ATN_XFER);
                  hostdata->state = S_RUNNING_LEVEL2;
                  }
               else {
                  write_wd33c93_cmd(regs, WD_CMD_NEGATE_ACK);
                  hostdata->state = S_CONNECTED;
                  }
               break;

            case DISCONNECT:
DB(DB_INTR,printk("DIS"))
               cmd->device->disconnect = 1;
               write_wd33c93_cmd(regs, WD_CMD_NEGATE_ACK);
               hostdata->state = S_PRE_TMP_DISC;
               break;

            case MESSAGE_REJECT:
DB(DB_INTR,printk("REJ"))
#ifdef SYNC_DEBUG
printk("-REJ-");
#endif
               if (hostdata->sync_stat[cmd->target] == SS_WAITING)
                  hostdata->sync_stat[cmd->target] = SS_SET;
               write_wd33c93_cmd(regs, WD_CMD_NEGATE_ACK);
               hostdata->state = S_CONNECTED;
               break;

            case EXTENDED_MESSAGE:
DB(DB_INTR,printk("EXT"))

               ucp = hostdata->incoming_msg;

#ifdef SYNC_DEBUG
printk("%02x",ucp[hostdata->incoming_ptr]);
#endif
         /* Is this the last byte of the extended message? */

               if ((hostdata->incoming_ptr >= 2) &&
                   (hostdata->incoming_ptr == (ucp[1] + 1))) {

                  switch (ucp[2]) {   /* what's the EXTENDED code? */
                     case EXTENDED_SDTR:
                        id = calc_sync_xfer(ucp[3],ucp[4]);
                        if (hostdata->sync_stat[cmd->target] != SS_WAITING) {

/* A device has sent an unsolicited SDTR message; rather than go
 * through the effort of decoding it and then figuring out what
 * our reply should be, we're just gonna say that we have a
 * synchronous fifo depth of 0. This will result in asynchronous
 * transfers - not ideal but so much easier.
 * Actually, this is OK because it assures us that if we don't
 * specifically ask for sync transfers, we won't do any.
 */

                           write_wd33c93_cmd(regs, WD_CMD_ASSERT_ATN); /* want MESS_OUT */
                           hostdata->outgoing_msg[0] = EXTENDED_MESSAGE;
                           hostdata->outgoing_msg[1] = 3;
                           hostdata->outgoing_msg[2] = EXTENDED_SDTR;
                           hostdata->outgoing_msg[3] = hostdata->default_sx_per/4;
                           hostdata->outgoing_msg[4] = 0;
                           hostdata->outgoing_len = 5;
                           hostdata->sync_xfer[cmd->target] =
                                       calc_sync_xfer(hostdata->default_sx_per/4,0);
                           }
                        else {
                           hostdata->sync_xfer[cmd->target] = id;
                           }
#ifdef SYNC_DEBUG
printk("sync_xfer=%02x",hostdata->sync_xfer[cmd->target]);
#endif
                        hostdata->sync_stat[cmd->target] = SS_SET;
                        write_wd33c93_cmd(regs, WD_CMD_NEGATE_ACK);
                        hostdata->state = S_CONNECTED;
                        break;
                     case EXTENDED_WDTR:
                        write_wd33c93_cmd(regs, WD_CMD_ASSERT_ATN); /* want MESS_OUT */
                        printk("sending WDTR ");
                        hostdata->outgoing_msg[0] = EXTENDED_MESSAGE;
                        hostdata->outgoing_msg[1] = 2;
                        hostdata->outgoing_msg[2] = EXTENDED_WDTR;
                        hostdata->outgoing_msg[3] = 0;   /* 8 bit transfer width */
                        hostdata->outgoing_len = 4;
                        write_wd33c93_cmd(regs, WD_CMD_NEGATE_ACK);
                        hostdata->state = S_CONNECTED;
                        break;
                     default:
                        write_wd33c93_cmd(regs, WD_CMD_ASSERT_ATN); /* want MESS_OUT */
                        printk("Rejecting Unknown Extended Message(%02x). ",ucp[2]);
                        hostdata->outgoing_msg[0] = MESSAGE_REJECT;
                        hostdata->outgoing_len = 1;
                        write_wd33c93_cmd(regs, WD_CMD_NEGATE_ACK);
                        hostdata->state = S_CONNECTED;
                        break;
                     }
                  hostdata->incoming_ptr = 0;
                  }

         /* We need to read more MESS_IN bytes for the extended message */

               else {
                  hostdata->incoming_ptr++;
                  write_wd33c93_cmd(regs, WD_CMD_NEGATE_ACK);
                  hostdata->state = S_CONNECTED;
                  }
               break;

            default:
               printk("Rejecting Unknown Message(%02x) ",msg);
               write_wd33c93_cmd(regs, WD_CMD_ASSERT_ATN); /* want MESS_OUT */
               hostdata->outgoing_msg[0] = MESSAGE_REJECT;
               hostdata->outgoing_len = 1;
               write_wd33c93_cmd(regs, WD_CMD_NEGATE_ACK);
               hostdata->state = S_CONNECTED;
            }
         restore_flags(flags);
         break;


/* Note: this interrupt will occur only after a LEVEL2 command */

      case CSR_SEL_XFER_DONE:

/* Make sure that reselection is enabled at this point - it may
 * have been turned off for the command that just completed.
 */

         write_wd33c93(regs, WD_SOURCE_ID, SRCID_ER);
         if (phs == 0x60) {
DB(DB_INTR,printk("SX-DONE-%ld",cmd->pid))
            cmd->SCp.Message = COMMAND_COMPLETE;
            lun = read_wd33c93(regs, WD_TARGET_LUN);
DB(DB_INTR,printk(":%d.%d",cmd->SCp.Status,lun))
            hostdata->connected = NULL;
            hostdata->busy[cmd->target] &= ~(1 << cmd->lun);
            hostdata->state = S_UNCONNECTED;
            if (cmd->SCp.Status == ILLEGAL_STATUS_BYTE)
               cmd->SCp.Status = lun;
            if (cmd->cmnd[0] == REQUEST_SENSE && cmd->SCp.Status != GOOD)
               cmd->result = (cmd->result & 0x00ffff) | (DID_ERROR << 16);
            else
               cmd->result = cmd->SCp.Status | (cmd->SCp.Message << 8);
            cmd->scsi_done(cmd);

/* We are no longer  connected to a target - check to see if
 * there are commands waiting to be executed.
 */
       restore_flags(flags);
            wd33c93_execute(instance);
            }
         else {
            printk("%02x:%02x:%02x-%ld: Unknown SEL_XFER_DONE phase!!---",asr,sr,phs,cmd->pid);
            }
         break;


/* Note: this interrupt will occur only after a LEVEL2 command */

      case CSR_SDP:
DB(DB_INTR,printk("SDP"))
            hostdata->state = S_RUNNING_LEVEL2;
            write_wd33c93(regs, WD_COMMAND_PHASE, 0x41);
            write_wd33c93_cmd(regs, WD_CMD_SEL_ATN_XFER);
         break;


      case CSR_XFER_DONE|PHS_MESS_OUT:
      case CSR_UNEXP    |PHS_MESS_OUT:
      case CSR_SRV_REQ  |PHS_MESS_OUT:
DB(DB_INTR,printk("MSG_OUT="))

/* To get here, we've probably requested MESSAGE_OUT and have
 * already put the correct bytes in outgoing_msg[] and filled
 * in outgoing_len. We simply send them out to the SCSI bus.
 * Sometimes we get MESSAGE_OUT phase when we're not expecting
 * it - like when our SDTR message is rejected by a target. Some
 * targets send the REJECT before receiving all of the extended
 * message, and then seem to go back to MESSAGE_OUT for a byte
 * or two. Not sure why, or if I'm doing something wrong to
 * cause this to happen. Regardless, it seems that sending
 * NOP messages in these situations results in no harm and
 * makes everyone happy.
 */

         if (hostdata->outgoing_len == 0) {
            hostdata->outgoing_len = 1;
            hostdata->outgoing_msg[0] = NOP;
            }
         transfer_pio(regs, hostdata->outgoing_msg, hostdata->outgoing_len,
                            DATA_OUT_DIR, hostdata);
DB(DB_INTR,printk("%02x",hostdata->outgoing_msg[0]))
         hostdata->outgoing_len = 0;
         hostdata->state = S_CONNECTED;
         break;


      case CSR_UNEXP_DISC:

/* I think I've seen this after a request-sense that was in response
 * to an error condition, but not sure. We certainly need to do
 * something when we get this interrupt - the question is 'what?'.
 * Let's think positively, and assume some command has finished
 * in a legal manner (like a command that provokes a request-sense),
 * so we treat it as a normal command-complete-disconnect.
 */

/* Make sure that reselection is enabled at this point - it may
 * have been turned off for the command that just completed.
 */

         write_wd33c93(regs, WD_SOURCE_ID, SRCID_ER);
         if (cmd == NULL) {
            printk(" - Already disconnected! ");
            hostdata->state = S_UNCONNECTED;
            return;
            }
DB(DB_INTR,printk("UNEXP_DISC-%ld",cmd->pid))
         hostdata->connected = NULL;
         hostdata->busy[cmd->target] &= ~(1 << cmd->lun);
         hostdata->state = S_UNCONNECTED;
         if (cmd->cmnd[0] == REQUEST_SENSE && cmd->SCp.Status != GOOD)
            cmd->result = (cmd->result & 0x00ffff) | (DID_ERROR << 16);
         else
            cmd->result = cmd->SCp.Status | (cmd->SCp.Message << 8);
         cmd->scsi_done(cmd);

/* We are no longer connected to a target - check to see if
 * there are commands waiting to be executed.
 */
    /* look above for comments on scsi_done() */
    restore_flags(flags);
         wd33c93_execute(instance);
         break;


      case CSR_DISC:

/* Make sure that reselection is enabled at this point - it may
 * have been turned off for the command that just completed.
 */

         write_wd33c93(regs, WD_SOURCE_ID, SRCID_ER);
DB(DB_INTR,printk("DISC-%ld",cmd->pid))
         if (cmd == NULL) {
            printk(" - Already disconnected! ");
            hostdata->state = S_UNCONNECTED;
            }
         switch (hostdata->state) {
            case S_PRE_CMP_DISC:
               hostdata->connected = NULL;
               hostdata->busy[cmd->target] &= ~(1 << cmd->lun);
               hostdata->state = S_UNCONNECTED;
DB(DB_INTR,printk(":%d",cmd->SCp.Status))
               if (cmd->cmnd[0] == REQUEST_SENSE && cmd->SCp.Status != GOOD)
                  cmd->result = (cmd->result & 0x00ffff) | (DID_ERROR << 16);
               else
                  cmd->result = cmd->SCp.Status | (cmd->SCp.Message << 8);
               cmd->scsi_done(cmd);
          restore_flags(flags);
               break;
            case S_PRE_TMP_DISC:
            case S_RUNNING_LEVEL2:
               cmd->host_scribble = (uchar *)hostdata->disconnected_Q;
               hostdata->disconnected_Q = cmd;
               hostdata->connected = NULL;
               hostdata->state = S_UNCONNECTED;

#ifdef PROC_STATISTICS
               hostdata->disc_done_cnt[cmd->target]++;
#endif

               break;
            default:
               printk("*** Unexpected DISCONNECT interrupt! ***");
               hostdata->state = S_UNCONNECTED;
            }

/* We are no longer connected to a target - check to see if
 * there are commands waiting to be executed.
 */
         wd33c93_execute(instance);
         break;


      case CSR_RESEL_AM:
      case CSR_RESEL:
DB(DB_INTR,printk("RESEL%s", sr == CSR_RESEL_AM ? "_AM" : ""))

   /* Old chips (pre -A ???) don't have advanced features and will
    * generate CSR_RESEL.  In that case we have to extract the LUN the
    * hard way (see below).
    * First we have to make sure this reselection didn't
    * happen during Arbitration/Selection of some other device.
    * If yes, put losing command back on top of input_Q.
    */

         if (hostdata->level2 <= L2_NONE) {

            if (hostdata->selecting) {
               cmd = (Scsi_Cmnd *)hostdata->selecting;
               hostdata->selecting = NULL;
               hostdata->busy[cmd->target] &= ~(1 << cmd->lun);
               cmd->host_scribble = (uchar *)hostdata->input_Q;
               hostdata->input_Q = cmd;
               }
            }

         else {

            if (cmd) {
               if (phs == 0x00) {
                  hostdata->busy[cmd->target] &= ~(1 << cmd->lun);
                  cmd->host_scribble = (uchar *)hostdata->input_Q;
                  hostdata->input_Q = cmd;
                  }
               else {
                  printk("---%02x:%02x:%02x-TROUBLE: Intrusive ReSelect!---",asr,sr,phs);
                  while (1)
                     printk("\r");
                  }
               }

            }

   /* OK - find out which device reselected us. */

         id = read_wd33c93(regs, WD_SOURCE_ID);
         id &= SRCID_MASK;

   /* and extract the lun from the ID message. (Note that we don't
    * bother to check for a valid message here - I guess this is
    * not the right way to go, but...)
    */

         if (sr == CSR_RESEL_AM) {
            lun = read_wd33c93(regs, WD_DATA);
            if (hostdata->level2 < L2_RESELECT)
               write_wd33c93_cmd(regs, WD_CMD_NEGATE_ACK);
            lun &= 7;
         }
         else {
            /* Old chip; wait for msgin phase to pick up the LUN. */
            for (lun = 255; lun; lun--) {
               if ((asr = READ_AUX_STAT()) & ASR_INT)
                  break;
               udelay(10);
            }
            if (!(asr & ASR_INT)) {
               printk("wd33c93: Reselected without IDENTIFY\n");
               lun = 0;
            }
            else {
               /* Verify this is a change to MSG_IN and read the message */
               sr = read_wd33c93(regs, WD_SCSI_STATUS);
               if (sr == (CSR_ABORT   | PHS_MESS_IN) ||
                   sr == (CSR_UNEXP   | PHS_MESS_IN) ||
                   sr == (CSR_SRV_REQ | PHS_MESS_IN)) {
                  /* Got MSG_IN, grab target LUN */
                  lun = read_1_byte(regs);
                  /* Now we expect a 'paused with ACK asserted' int.. */
                  asr = READ_AUX_STAT();
                  if (!(asr & ASR_INT)) {
                     udelay(10);
                     asr = READ_AUX_STAT();
                     if (!(asr & ASR_INT))
                        printk("wd33c93: No int after LUN on RESEL (%02x)\n",
                              asr);
                  }
                  sr = read_wd33c93(regs, WD_SCSI_STATUS);
                  if (sr != CSR_MSGIN)
                     printk("wd33c93: Not paused with ACK on RESEL (%02x)\n",
                           sr);
                  lun &= 7;
                  write_wd33c93_cmd(regs, WD_CMD_NEGATE_ACK);
               }
               else {
                  printk("wd33c93: Not MSG_IN on reselect (%02x)\n", sr);
                  lun = 0;
               }
            }
         }

   /* Now we look for the command that's reconnecting. */

         cmd = (Scsi_Cmnd *)hostdata->disconnected_Q;
         patch = NULL;
         while (cmd) {
            if (id == cmd->target && lun == cmd->lun)
               break;
            patch = cmd;
            cmd = (Scsi_Cmnd *)cmd->host_scribble;
            }

   /* Hmm. Couldn't find a valid command.... What to do? */

         if (!cmd) {
            printk("---TROUBLE: target %d.%d not in disconnect queue---",id,lun);
            return;
            }

   /* Ok, found the command - now start it up again. */

         if (patch)
            patch->host_scribble = cmd->host_scribble;
         else
            hostdata->disconnected_Q = (Scsi_Cmnd *)cmd->host_scribble;
         hostdata->connected = cmd;

   /* We don't need to worry about 'initialize_SCp()' or 'hostdata->busy[]'
    * because these things are preserved over a disconnect.
    * But we DO need to fix the DPD bit so it's correct for this command.
    */

         if (is_dir_out(cmd))
            write_wd33c93(regs, WD_DESTINATION_ID, cmd->target);
         else
            write_wd33c93(regs, WD_DESTINATION_ID, cmd->target | DSTID_DPD);
         if (hostdata->level2 >= L2_RESELECT) {
            write_wd33c93_count(regs, 0);  /* we want a DATA_PHASE interrupt */
            write_wd33c93(regs, WD_COMMAND_PHASE, 0x45);
            write_wd33c93_cmd(regs, WD_CMD_SEL_ATN_XFER);
            hostdata->state = S_RUNNING_LEVEL2;
            }
         else
            hostdata->state = S_CONNECTED;

DB(DB_INTR,printk("-%ld",cmd->pid))
         break;

      default:
         printk("--UNKNOWN INTERRUPT:%02x:%02x:%02x--",asr,sr,phs);
      }

DB(DB_INTR,printk("} "))

}



void reset_wd33c93(struct Scsi_Host *instance)
{
struct WD33C93_hostdata *hostdata = (struct WD33C93_hostdata *)instance->hostdata;
const wd33c93_regs regs = hostdata->regs;
uchar sr;

#ifdef CONFIG_SGI_IP22
{
int busycount = 0;
extern void sgiwd93_reset(unsigned long);
   /* wait 'til the chip gets some time for us */
   while ((READ_AUX_STAT() & ASR_BSY) && busycount++ < 100)
	udelay (10);
   /*
    * there are scsi devices out there, which manage to lock up
    * the wd33c93 in a busy condition. In this state it won't
    * accept the reset command. The only way to solve this is to
    * give the chip a hardware reset (if possible). The code below
    * does this for the SGI Indy, where this is possible
    */
   /* still busy ? */
   if (READ_AUX_STAT() & ASR_BSY)
	sgiwd93_reset(instance->base); /* yeah, give it the hard one */
}
#endif

   write_wd33c93(regs, WD_OWN_ID, OWNID_EAF | OWNID_RAF |
                 instance->this_id | hostdata->clock_freq);
   write_wd33c93(regs, WD_CONTROL, CTRL_IDI | CTRL_EDI | CTRL_POLLED);
   write_wd33c93(regs, WD_SYNCHRONOUS_TRANSFER,
                 calc_sync_xfer(hostdata->default_sx_per/4,DEFAULT_SX_OFF));
   write_wd33c93(regs, WD_COMMAND, WD_CMD_RESET);
#ifdef CONFIG_MVME147_SCSI
   udelay(25); /* The old wd33c93 on MVME147 needs this, at least */
#endif

   while (!(READ_AUX_STAT() & ASR_INT))
      ;
   sr = read_wd33c93(regs, WD_SCSI_STATUS);

   hostdata->microcode = read_wd33c93(regs, WD_CDB_1);
   if (sr == 0x00)
      hostdata->chip = C_WD33C93;
   else if (sr == 0x01) {
      write_wd33c93(regs, WD_QUEUE_TAG, 0xa5);  /* any random number */
      sr = read_wd33c93(regs, WD_QUEUE_TAG);
      if (sr == 0xa5) {
         hostdata->chip = C_WD33C93B;
         write_wd33c93(regs, WD_QUEUE_TAG, 0);
         }
      else
         hostdata->chip = C_WD33C93A;
      }
   else
      hostdata->chip = C_UNKNOWN_CHIP;

   write_wd33c93(regs, WD_TIMEOUT_PERIOD, TIMEOUT_PERIOD_VALUE);
   write_wd33c93(regs, WD_CONTROL, CTRL_IDI | CTRL_EDI | CTRL_POLLED);
}



int wd33c93_reset(Scsi_Cmnd *SCpnt, unsigned int reset_flags)
{
struct Scsi_Host *instance;
struct WD33C93_hostdata *hostdata;
int i;

   instance = SCpnt->host;
   hostdata = (struct WD33C93_hostdata *)instance->hostdata;

   printk("scsi%d: reset. ", instance->host_no);
   disable_irq(instance->irq);

   ((struct WD33C93_hostdata *)instance->hostdata)->dma_stop(instance,NULL,0);
   for (i = 0; i < 8; i++) {
      hostdata->busy[i] = 0;
      hostdata->sync_xfer[i] = calc_sync_xfer(DEFAULT_SX_PER/4,DEFAULT_SX_OFF);
      hostdata->sync_stat[i] = SS_UNSET;  /* using default sync values */
      }
   hostdata->input_Q = NULL;
   hostdata->selecting = NULL;
   hostdata->connected = NULL;
   hostdata->disconnected_Q = NULL;
   hostdata->state = S_UNCONNECTED;
   hostdata->dma = D_DMA_OFF;
   hostdata->incoming_ptr = 0;
   hostdata->outgoing_len = 0;

   reset_wd33c93(instance);
   SCpnt->result = DID_RESET << 16;
   enable_irq(instance->irq);
   return 0;
}



int wd33c93_abort (Scsi_Cmnd *cmd)
{
struct Scsi_Host *instance;
struct WD33C93_hostdata *hostdata;
wd33c93_regs regs;
Scsi_Cmnd *tmp, *prev;

   disable_irq(cmd->host->irq);

   instance = cmd->host;
   hostdata = (struct WD33C93_hostdata *)instance->hostdata;
   regs = hostdata->regs;

/*
 * Case 1 : If the command hasn't been issued yet, we simply remove it
 *     from the input_Q.
 */

   tmp = (Scsi_Cmnd *)hostdata->input_Q;
   prev = 0;
   while (tmp) {
      if (tmp == cmd) {
         if (prev)
            prev->host_scribble = cmd->host_scribble;
	 else
            hostdata->input_Q = (Scsi_Cmnd *)cmd->host_scribble;
         cmd->host_scribble = NULL;
         cmd->result = DID_ABORT << 16;
         printk("scsi%d: Abort - removing command %ld from input_Q. ",
           instance->host_no, cmd->pid);
    enable_irq(cmd->host->irq);
         cmd->scsi_done(cmd);
         return SCSI_ABORT_SUCCESS;
         }
      prev = tmp;
      tmp = (Scsi_Cmnd *)tmp->host_scribble;
      }

/*
 * Case 2 : If the command is 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 == cmd) {
      uchar sr, asr;
      unsigned long timeout;

      printk("scsi%d: Aborting connected command %ld - ",
              instance->host_no, cmd->pid);

      printk("stopping DMA - ");
      if (hostdata->dma == D_DMA_RUNNING) {
         hostdata->dma_stop(instance, cmd, 0);
         hostdata->dma = D_DMA_OFF;
         }

      printk("sending wd33c93 ABORT command - ");
      write_wd33c93(regs, WD_CONTROL, CTRL_IDI | CTRL_EDI | CTRL_POLLED);
      write_wd33c93_cmd(regs, WD_CMD_ABORT);

/* Now we have to attempt to flush out the FIFO... */

      printk("flushing fifo - ");
      timeout = 1000000;
      do {
         asr = READ_AUX_STAT();
         if (asr & ASR_DBR)
            read_wd33c93(regs, WD_DATA);
         } while (!(asr & ASR_INT) && timeout-- > 0);
      sr = read_wd33c93(regs, WD_SCSI_STATUS);
      printk("asr=%02x, sr=%02x, %ld bytes un-transferred (timeout=%ld) - ",
             asr, sr, read_wd33c93_count(regs), timeout);

   /*
    * Abort command processed.
    * Still connected.
    * We must disconnect.
    */

      printk("sending wd33c93 DISCONNECT command - ");
      write_wd33c93_cmd(regs, WD_CMD_DISCONNECT);

      timeout = 1000000;
      asr = READ_AUX_STAT();
      while ((asr & ASR_CIP) && timeout-- > 0)
         asr = READ_AUX_STAT();
      sr = read_wd33c93(regs, WD_SCSI_STATUS);
      printk("asr=%02x, sr=%02x.",asr,sr);

      hostdata->busy[cmd->target] &= ~(1 << cmd->lun);
      hostdata->connected = NULL;
      hostdata->state = S_UNCONNECTED;
      cmd->result = DID_ABORT << 16;

/*      sti();*/
      wd33c93_execute (instance);

      enable_irq(cmd->host->irq);
      cmd->scsi_done(cmd);
      return SCSI_ABORT_SUCCESS;
      }

/*
 * Case 3: If the command is currently disconnected from the bus,
 * we're not going to expend much effort here: Let's just return
 * an ABORT_SNOOZE and hope for the best...
 */

   tmp = (Scsi_Cmnd *)hostdata->disconnected_Q;
   while (tmp) {
      if (tmp == cmd) {
         printk("scsi%d: Abort - command %ld found on disconnected_Q - ",
                 instance->host_no, cmd->pid);
         printk("returning ABORT_SNOOZE. ");
    enable_irq(cmd->host->irq);
         return SCSI_ABORT_SNOOZE;
         }
      tmp = (Scsi_Cmnd *)tmp->host_scribble;
      }

/*
 * Case 4 : 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.
 */

/*   sti();*/
   wd33c93_execute (instance);

   enable_irq(cmd->host->irq);
   printk("scsi%d: warning : SCSI command probably completed successfully"
      "         before abortion. ", instance->host_no);
   return SCSI_ABORT_NOT_RUNNING;
}



#define MAX_WD33C93_HOSTS 4
#define MAX_SETUP_ARGS ((int)(sizeof(setup_args) / sizeof(char *)))
#define SETUP_BUFFER_SIZE 200
static char setup_buffer[SETUP_BUFFER_SIZE];
static char setup_used[MAX_SETUP_ARGS];
static int done_setup = 0;

int wd33c93_setup (char *str)
{
   int i;
   char *p1,*p2;

   /* The kernel does some processing of the command-line before calling
    * this function: If it begins with any decimal or hex number arguments,
    * ints[0] = how many numbers found and ints[1] through [n] are the values
    * themselves. str points to where the non-numeric arguments (if any)
    * start: We do our own parsing of those. We construct synthetic 'nosync'
    * keywords out of numeric args (to maintain compatibility with older
    * versions) and then add the rest of the arguments.
    */

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

   return 1;
}

__setup("wd33c93", wd33c93_setup);


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

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

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



void wd33c93_init(struct Scsi_Host *instance, const wd33c93_regs regs,
		  dma_setup_t setup, dma_stop_t stop, int clock_freq)
{
struct WD33C93_hostdata *hostdata;
int i;
int flags;
int val;
char buf[32];

   if (!done_setup && setup_strings)
      wd33c93_setup(setup_strings);

   hostdata = (struct WD33C93_hostdata *)instance->hostdata;

   hostdata->regs = regs;
   hostdata->clock_freq = clock_freq;
   hostdata->dma_setup = setup;
   hostdata->dma_stop = stop;
   hostdata->dma_bounce_buffer = NULL;
   hostdata->dma_bounce_len = 0;
   for (i = 0; i < 8; i++) {
      hostdata->busy[i] = 0;
      hostdata->sync_xfer[i] = calc_sync_xfer(DEFAULT_SX_PER/4,DEFAULT_SX_OFF);
      hostdata->sync_stat[i] = SS_UNSET;  /* using default sync values */
#ifdef PROC_STATISTICS
      hostdata->cmd_cnt[i] = 0;
      hostdata->disc_allowed_cnt[i] = 0;
      hostdata->disc_done_cnt[i] = 0;
#endif
      }
   hostdata->input_Q = NULL;
   hostdata->selecting = NULL;
   hostdata->connected = NULL;
   hostdata->disconnected_Q = NULL;
   hostdata->state = S_UNCONNECTED;
   hostdata->dma = D_DMA_OFF;
   hostdata->level2 = L2_BASIC;
   hostdata->disconnect = DIS_ADAPTIVE;
   hostdata->args = DEBUG_DEFAULTS;
   hostdata->incoming_ptr = 0;
   hostdata->outgoing_len = 0;
   hostdata->default_sx_per = DEFAULT_SX_PER;
   hostdata->no_sync = 0xff;     /* sync defaults to off */
   hostdata->no_dma = 0;         /* default is DMA enabled */

#ifdef PROC_INTERFACE
   hostdata->proc = PR_VERSION|PR_INFO|PR_STATISTICS|
                    PR_CONNECTED|PR_INPUTQ|PR_DISCQ|
                    PR_STOP;
#ifdef PROC_STATISTICS
   hostdata->dma_cnt = 0;
   hostdata->pio_cnt = 0;
   hostdata->int_cnt = 0;
#endif
#endif


   if (check_setup_args("nosync",&flags,&val,buf))
      hostdata->no_sync = val;

   if (check_setup_args("nodma",&flags,&val,buf))
      hostdata->no_dma = (val == -1) ? 1 : val;

   if (check_setup_args("period",&flags,&val,buf))
      hostdata->default_sx_per = sx_table[round_period((unsigned int)val)].period_ns;

   if (check_setup_args("disconnect",&flags,&val,buf)) {
      if ((val >= DIS_NEVER) && (val <= DIS_ALWAYS))
         hostdata->disconnect = val;
      else
         hostdata->disconnect = DIS_ADAPTIVE;
      }

   if (check_setup_args("level2",&flags,&val,buf))
      hostdata->level2 = val;

   if (check_setup_args("debug",&flags,&val,buf))
      hostdata->args = val & DB_MASK;

   if (check_setup_args("clock",&flags,&val,buf)) {
      if (val>7 && val<11)
         val = WD33C93_FS_8_10;
      else if (val>11 && val<16)
         val = WD33C93_FS_12_15;
      else if (val>15 && val<21)
         val = WD33C93_FS_16_20;
      else
         val = WD33C93_FS_8_10;
      hostdata->clock_freq = val;
      }

   if ((i = check_setup_args("next",&flags,&val,buf))) {
      while (i)
         setup_used[--i] = 1;
      }

#ifdef PROC_INTERFACE
   if (check_setup_args("proc",&flags,&val,buf))
      hostdata->proc = val;
#endif


   { unsigned long flags;
     save_flags(flags);
     cli();
     reset_wd33c93(instance);
     restore_flags(flags);
   }

   printk("wd33c93-%d: chip=%s/%d no_sync=0x%x no_dma=%d",instance->host_no,
         (hostdata->chip==C_WD33C93)?"WD33c93":
         (hostdata->chip==C_WD33C93A)?"WD33c93A":
         (hostdata->chip==C_WD33C93B)?"WD33c93B":"unknown",
         hostdata->microcode,hostdata->no_sync,hostdata->no_dma);
#ifdef DEBUGGING_ON
   printk(" debug_flags=0x%02x\n",hostdata->args);
#else
   printk(" debugging=OFF\n");
#endif
   printk("           setup_args=");
   for (i=0; i<MAX_SETUP_ARGS; i++)
      printk("%s,",setup_args[i]);
   printk("\n");
   printk("           Version %s - %s, Compiled %s at %s\n",
               WD33C93_VERSION,WD33C93_DATE,__DATE__,__TIME__);
   MOD_INC_USE_COUNT;
}


int wd33c93_proc_info(char *buf, char **start, off_t off, int len, int hn, int in)
{

#ifdef PROC_INTERFACE

char *bp;
char tbuf[128];
unsigned long flags;
struct Scsi_Host *instance;
struct WD33C93_hostdata *hd;
Scsi_Cmnd *cmd;
int x,i;
static int stop = 0;

   for (instance=scsi_hostlist; instance; instance=instance->next) {
      if (instance->host_no == hn)
         break;
      }
   if (!instance) {
      printk("*** Hmm... Can't find host #%d!\n",hn);
      return (-ESRCH);
      }
   hd = (struct WD33C93_hostdata *)instance->hostdata;

/* If 'in' is TRUE we need to _read_ the proc file. We accept the following
 * keywords (same format as command-line, but only ONE per read):
 *    debug
 *    disconnect
 *    period
 *    resync
 *    proc
 *    nodma
 */

   if (in) {
      buf[len] = '\0';
      bp = buf;
      if (!strncmp(bp,"debug:",6)) {
         bp += 6;
         hd->args = simple_strtoul(bp,NULL,0) & DB_MASK;
         }
      else if (!strncmp(bp,"disconnect:",11)) {
         bp += 11;
         x = simple_strtoul(bp,NULL,0);
         if (x < DIS_NEVER || x > DIS_ALWAYS)
            x = DIS_ADAPTIVE;
         hd->disconnect = x;
         }
      else if (!strncmp(bp,"period:",7)) {
         bp += 7;
         x = simple_strtoul(bp,NULL,0);
         hd->default_sx_per = sx_table[round_period((unsigned int)x)].period_ns;
         }
      else if (!strncmp(bp,"resync:",7)) {
         bp += 7;
         x = simple_strtoul(bp,NULL,0);
         for (i=0; i<7; i++)
            if (x & (1<<i))
               hd->sync_stat[i] = SS_UNSET;
         }
      else if (!strncmp(bp,"proc:",5)) {
         bp += 5;
         hd->proc = simple_strtoul(bp,NULL,0);
         }
      else if (!strncmp(bp,"nodma:",6)) {
         bp += 6;
         hd->no_dma = simple_strtoul(bp,NULL,0);
         }
      else if (!strncmp(bp,"level2:",7)) {
         bp += 7;
         hd->level2 = simple_strtoul(bp,NULL,0);
         }
      return len;
      }

   save_flags(flags);
   cli();
   bp = buf;
   *bp = '\0';
   if (hd->proc & PR_VERSION) {
      sprintf(tbuf,"\nVersion %s - %s. Compiled %s %s",
            WD33C93_VERSION,WD33C93_DATE,__DATE__,__TIME__);
      strcat(bp,tbuf);
      }
   if (hd->proc & PR_INFO) {
      sprintf(tbuf,"\nclock_freq=%02x no_sync=%02x no_dma=%d",
            hd->clock_freq,hd->no_sync,hd->no_dma);
      strcat(bp,tbuf);
      strcat(bp,"\nsync_xfer[] =       ");
      for (x=0; x<7; x++) {
         sprintf(tbuf,"\t%02x",hd->sync_xfer[x]);
         strcat(bp,tbuf);
         }
      strcat(bp,"\nsync_stat[] =       ");
      for (x=0; x<7; x++) {
         sprintf(tbuf,"\t%02x",hd->sync_stat[x]);
         strcat(bp,tbuf);
         }
      }
#ifdef PROC_STATISTICS
   if (hd->proc & PR_STATISTICS) {
      strcat(bp,"\ncommands issued:    ");
      for (x=0; x<7; x++) {
         sprintf(tbuf,"\t%ld",hd->cmd_cnt[x]);
         strcat(bp,tbuf);
         }
      strcat(bp,"\ndisconnects allowed:");
      for (x=0; x<7; x++) {
         sprintf(tbuf,"\t%ld",hd->disc_allowed_cnt[x]);
         strcat(bp,tbuf);
         }
      strcat(bp,"\ndisconnects done:   ");
      for (x=0; x<7; x++) {
         sprintf(tbuf,"\t%ld",hd->disc_done_cnt[x]);
         strcat(bp,tbuf);
         }
      sprintf(tbuf,"\ninterrupts: %ld, DATA_PHASE ints: %ld DMA, %ld PIO",
            hd->int_cnt,hd->dma_cnt,hd->pio_cnt);
      strcat(bp,tbuf);
      }
#endif
   if (hd->proc & PR_CONNECTED) {
      strcat(bp,"\nconnected:     ");
      if (hd->connected) {
         cmd = (Scsi_Cmnd *)hd->connected;
         sprintf(tbuf," %ld-%d:%d(%02x)",
               cmd->pid, cmd->target, cmd->lun, cmd->cmnd[0]);
         strcat(bp,tbuf);
         }
      }
   if (hd->proc & PR_INPUTQ) {
      strcat(bp,"\ninput_Q:       ");
      cmd = (Scsi_Cmnd *)hd->input_Q;
      while (cmd) {
         sprintf(tbuf," %ld-%d:%d(%02x)",
               cmd->pid, cmd->target, cmd->lun, cmd->cmnd[0]);
         strcat(bp,tbuf);
         cmd = (Scsi_Cmnd *)cmd->host_scribble;
         }
      }
   if (hd->proc & PR_DISCQ) {
      strcat(bp,"\ndisconnected_Q:");
      cmd = (Scsi_Cmnd *)hd->disconnected_Q;
      while (cmd) {
         sprintf(tbuf," %ld-%d:%d(%02x)",
               cmd->pid, cmd->target, cmd->lun, cmd->cmnd[0]);
         strcat(bp,tbuf);
         cmd = (Scsi_Cmnd *)cmd->host_scribble;
         }
      }
   strcat(bp,"\n");
   restore_flags(flags);
   *start = buf;
   if (stop) {
      stop = 0;
      return 0;
      }
   if (off > 0x40000)   /* ALWAYS stop after 256k bytes have been read */
      stop = 1;;
   if (hd->proc & PR_STOP)    /* stop every other time */
      stop = 1;
   return strlen(bp);

#else    /* PROC_INTERFACE */

   return 0;

#endif   /* PROC_INTERFACE */

}

#ifdef MODULE
int init_module(void) { return 0; }
void cleanup_module(void) {}
#endif
void wd33c93_release(void)
{
   MOD_DEC_USE_COUNT;
}

MODULE_LICENSE("GPL");