// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (c) 1996 John Shifflett, GeoLog Consulting
 *    john@geolog.com
 *    jshiffle@netcom.com
 */

/*
 * 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
 *
 * Added support for Burst Mode DMA and Fast SCSI. Enabled the use of
 * default_sx_per for asynchronous data transfers. Added adjustment
 * of transfer periods in sx_table to the actual input-clock.
 *  peter fuerst <post@pfrst.de>  February 2007
 */

#include <linux/module.h>

#include <linux/string.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/blkdev.h>

#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>

#include <asm/irq.h>

#include "wd33c93.h"

#define optimum_sx_per(hostdata) (hostdata)->sx_table[1].period_ns


#define WD33C93_VERSION    "1.26++"
#define WD33C93_DATE       "10/Feb/2007"

MODULE_AUTHOR("John Shifflett");
MODULE_DESCRIPTION("Generic WD33C93 SCSI driver");
MODULE_LICENSE("GPL");

/*
 * '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.
 * -  burst:x        -x = 1 to use Burst Mode (or Demand-Mode) DMA, x = 0 to use
 *                    Single Byte DMA, which is the default. Argument is
 *                    optional - if not present, same as "burst:1".
 * -  fast:x         -x = 1 to enable Fast SCSI, which is only effective with
 *                    input-clock divisor 4 (WD33C93_FS_16_20), x = 0 to disable
 *                    it, which is the default.  Argument is optional - if not
 *                    present, same as "fast:1".
 * -  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[] = { "", "", "", "", "", "", "", "", "", "" };

static char *setup_strings;
module_param(setup_strings, charp, 0);

static void wd33c93_execute(struct Scsi_Host *instance);

#ifdef CONFIG_WD33C93_PIO
static inline uchar
read_wd33c93(const wd33c93_regs regs, uchar reg_num)
{
	uchar data;

	outb(reg_num, regs.SASR);
	data = inb(regs.SCMD);
	return data;
}

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

	outb(WD_TRANSFER_COUNT_MSB, regs.SASR);
	value = inb(regs.SCMD) << 16;
	value |= inb(regs.SCMD) << 8;
	value |= inb(regs.SCMD);
	return value;
}

static inline uchar
read_aux_stat(const wd33c93_regs regs)
{
	return inb(regs.SASR);
}

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

static inline void
write_wd33c93_count(const wd33c93_regs regs, unsigned long value)
{
	outb(WD_TRANSFER_COUNT_MSB, regs.SASR);
	outb((value >> 16) & 0xff, regs.SCMD);
	outb((value >> 8) & 0xff, regs.SCMD);
	outb( value & 0xff, regs.SCMD);
}

#define write_wd33c93_cmd(regs, cmd) \
	write_wd33c93((regs), WD_COMMAND, (cmd))

static inline void
write_wd33c93_cdb(const wd33c93_regs regs, uint len, uchar cmnd[])
{
	int i;

	outb(WD_CDB_1, regs.SASR);
	for (i=0; i<len; i++)
		outb(cmnd[i], regs.SCMD);
}

#else /* CONFIG_WD33C93_PIO */
static inline uchar
read_wd33c93(const wd33c93_regs regs, uchar reg_num)
{
	*regs.SASR = reg_num;
	mb();
	return (*regs.SCMD);
}

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;
}

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

static inline void
write_wd33c93_cdb(const wd33c93_regs regs, uint len, uchar cmnd[])
{
	int i;

	*regs.SASR = WD_CDB_1;
	for (i = 0; i < len; i++)
		*regs.SCMD = cmnd[i];
}
#endif /* CONFIG_WD33C93_PIO */

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(regs);
		if (asr & ASR_DBR)
			x = read_wd33c93(regs, WD_DATA);
	} while (!(asr & ASR_INT));
	return x;
}

static int
round_period(unsigned int period, const struct sx_period *sx_table)
{
	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;
}

/*
 * Calculate Synchronous Transfer Register value from SDTR code.
 */
static uchar
calc_sync_xfer(unsigned int period, unsigned int offset, unsigned int fast,
               const struct sx_period *sx_table)
{
	/* When doing Fast SCSI synchronous data transfers, the corresponding
	 * value in 'sx_table' is two times the actually used transfer period.
	 */
	uchar result;

	if (offset && fast) {
		fast = STR_FSS;
		period *= 2;
	} else {
		fast = 0;
	}
	period *= 4;		/* convert SDTR code to ns */
	result = sx_table[round_period(period,sx_table)].reg_value;
	result |= (offset < OPTIMUM_SX_OFF) ? offset : OPTIMUM_SX_OFF;
	result |= fast;
	return result;
}

/*
 * Calculate SDTR code bytes [3],[4] from period and offset.
 */
static inline void
calc_sync_msg(unsigned int period, unsigned int offset, unsigned int fast,
                uchar  msg[2])
{
	/* 'period' is a "normal"-mode value, like the ones in 'sx_table'. The
	 * actually used transfer period for Fast SCSI synchronous data
	 * transfers is half that value.
	 */
	period /= 4;
	if (offset && fast)
		period /= 2;
	msg[0] = period;
	msg[1] = offset;
}

static int
wd33c93_queuecommand_lck(struct scsi_cmnd *cmd,
		void (*done)(struct scsi_cmnd *))
{
	struct WD33C93_hostdata *hostdata;
	struct scsi_cmnd *tmp;

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

	DB(DB_QUEUE_COMMAND,
	   printk("Q-%d-%02x( ", cmd->device->id, cmd->cmnd[0]))

/* 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;

/* We use the Scsi_Pointer structure that's included with each command
 * as a scratchpad (as it's intended to be used!). The handy thing about
 * the SCp.xxx fields is that they're always associated with a given
 * cmd, and are preserved across disconnect-reselect. This means we
 * can pretty much ignore SAVE_POINTERS and RESTORE_POINTERS messages
 * if we keep all the critical pointers and counters in SCp:
 *  - SCp.ptr is the pointer into the RAM buffer
 *  - SCp.this_residual is the size of that buffer
 *  - SCp.buffer points to the current scatter-gather buffer
 *  - SCp.buffers_residual tells us how many S.G. buffers there are
 *  - SCp.have_data_in is not used
 *  - SCp.sent_command is not used
 *  - SCp.phase records this command's SRCID_ER bit setting
 */

	if (scsi_bufflen(cmd)) {
		cmd->SCp.buffer = scsi_sglist(cmd);
		cmd->SCp.buffers_residual = scsi_sg_count(cmd) - 1;
		cmd->SCp.ptr = sg_virt(cmd->SCp.buffer);
		cmd->SCp.this_residual = cmd->SCp.buffer->length;
	} else {
		cmd->SCp.buffer = NULL;
		cmd->SCp.buffers_residual = 0;
		cmd->SCp.ptr = NULL;
		cmd->SCp.this_residual = 0;
	}

/* 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.
	 */

	spin_lock_irq(&hostdata->lock);

	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 = (struct scsi_cmnd *) hostdata->input_Q;
		     tmp->host_scribble;
		     tmp = (struct 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->device->host);

	DB(DB_QUEUE_COMMAND, printk(")Q "))

	spin_unlock_irq(&hostdata->lock);
	return 0;
}

DEF_SCSI_QCMD(wd33c93_queuecommand)

/*
 * 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;
	struct scsi_cmnd *cmd, *prev;

	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 = (struct scsi_cmnd *) hostdata->input_Q;
	prev = NULL;
	while (cmd) {
		if (!(hostdata->busy[cmd->device->id] &
		      (1 << (cmd->device->lun & 0xff))))
			break;
		prev = cmd;
		cmd = (struct 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 = (struct scsi_cmnd *) cmd->host_scribble;

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

	/*
	 * Start the selection process
	 */

	if (cmd->sc_data_direction == DMA_TO_DEVICE)
		write_wd33c93(regs, WD_DESTINATION_ID, cmd->device->id);
	else
		write_wd33c93(regs, WD_DESTINATION_ID, cmd->device->id | 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 = (struct scsi_cmnd *) hostdata->input_Q; prev;
	     prev = (struct scsi_cmnd *) prev->host_scribble) {
		if ((prev->device->id != cmd->device->id) ||
		    (prev->device->lun != cmd->device->lun)) {
			for (prev = (struct scsi_cmnd *) hostdata->input_Q; prev;
			     prev = (struct 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->device->id]++;
#endif

 no:

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

	write_wd33c93(regs, WD_TARGET_LUN, (u8)cmd->device->lun);
	write_wd33c93(regs, WD_SYNCHRONOUS_TRANSFER,
		      hostdata->sync_xfer[cmd->device->id]);
	hostdata->busy[cmd->device->id] |= (1 << (cmd->device->lun & 0xFF));

	if ((hostdata->level2 == L2_NONE) ||
	    (hostdata->sync_stat[cmd->device->id] == 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->device->id] == SS_UNSET)
			hostdata->sync_stat[cmd->device->id] = 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)
		 */

		write_wd33c93_cdb(regs, cmd->cmd_len, cmd->cmnd);

		/* 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,
			    (cmd->sc_data_direction == DMA_TO_DEVICE) ?
			     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 | hostdata->dma_mode);
				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)EX-2 ", (cmd->SCp.phase) ? "d:" : ""))
}

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(regs);
			if (asr & ASR_DBR)
				*buf++ = read_wd33c93(regs, WD_DATA);
		} while (!(asr & ASR_INT));
	} else {
		do {
			asr = read_aux_stat(regs);
			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, struct scsi_cmnd *cmd,
		int data_in_dir)
{
	struct WD33C93_hostdata *hostdata;
	unsigned long length;

	hostdata = (struct WD33C93_hostdata *) cmd->device->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 = sg_next(cmd->SCp.buffer);
		--cmd->SCp.buffers_residual;
		cmd->SCp.this_residual = cmd->SCp.buffer->length;
		cmd->SCp.ptr = sg_virt(cmd->SCp.buffer);
	}
	if (!cmd->SCp.this_residual) /* avoid bogus setups */
		return;

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

/* '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 || hostdata->dma_setup(cmd, data_in_dir)) {
#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 | hostdata->dma_mode);
		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;
	struct scsi_cmnd *patch, *cmd;
	uchar asr, sr, phs, id, lun, *ucp, msg;
	unsigned long length, flags;

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

	spin_lock_irqsave(&hostdata->lock, flags);

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

	cmd = (struct 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->device->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 = (struct scsi_cmnd *) hostdata->selecting;	/* get a valid cmd */
			hostdata->selecting = NULL;
		}

		cmd->result = DID_NO_CONNECT << 16;
		hostdata->busy[cmd->device->id] &= ~(1 << (cmd->device->lun & 0xff));
		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...
		 */

		spin_unlock_irqrestore(&hostdata->lock, 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 =
		    (struct scsi_cmnd *) hostdata->selecting;
		hostdata->selecting = NULL;

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

		hostdata->outgoing_msg[0] = IDENTIFY(0, cmd->device->lun);
		if (cmd->SCp.phase)
			hostdata->outgoing_msg[0] |= 0x40;

		if (hostdata->sync_stat[cmd->device->id] == SS_FIRST) {

			hostdata->sync_stat[cmd->device->id] = 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->device->id)) {
				calc_sync_msg(hostdata->default_sx_per, 0,
						0, hostdata->outgoing_msg + 4);
			} else {
				calc_sync_msg(optimum_sx_per(hostdata),
						OPTIMUM_SX_OFF,
						hostdata->fast,
						hostdata->outgoing_msg + 4);
			}
			hostdata->outgoing_len = 6;
#ifdef SYNC_DEBUG
			ucp = hostdata->outgoing_msg + 1;
			printk(" sending SDTR %02x03%02x%02x%02x ",
				ucp[0], ucp[2], ucp[3], ucp[4]);
#endif
		} else
			hostdata->outgoing_len = 1;

		hostdata->state = S_CONNECTED;
		spin_unlock_irqrestore(&hostdata->lock, flags);
		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;
		spin_unlock_irqrestore(&hostdata->lock, flags);
		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;
		spin_unlock_irqrestore(&hostdata->lock, flags);
		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", cmd->cmnd[0]))
		    transfer_pio(regs, cmd->cmnd, cmd->cmd_len, DATA_OUT_DIR,
				 hostdata);
		hostdata->state = S_CONNECTED;
		spin_unlock_irqrestore(&hostdata->lock, flags);
		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 */
			udelay(7);
			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;
		}
		spin_unlock_irqrestore(&hostdata->lock, flags);
		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 */
		udelay(7);

		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"))
			    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->device->id] == SS_WAITING) {
				hostdata->sync_stat[cmd->device->id] = SS_SET;
				/* we want default_sx_per, not DEFAULT_SX_PER */
				hostdata->sync_xfer[cmd->device->id] =
					calc_sync_xfer(hostdata->default_sx_per
						/ 4, 0, 0, hostdata->sx_table);
			}
			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:
					/* default to default async period */
					id = calc_sync_xfer(hostdata->
							default_sx_per / 4, 0,
							0, hostdata->sx_table);
					if (hostdata->sync_stat[cmd->device->id] !=
					    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;
						calc_sync_msg(hostdata->
							default_sx_per, 0,
							0, hostdata->outgoing_msg + 3);
						hostdata->outgoing_len = 5;
					} else {
						if (ucp[4]) /* well, sync transfer */
							id = calc_sync_xfer(ucp[3], ucp[4],
									hostdata->fast,
									hostdata->sx_table);
						else if (ucp[3]) /* very unlikely... */
							id = calc_sync_xfer(ucp[3], ucp[4],
									0, hostdata->sx_table);
					}
					hostdata->sync_xfer[cmd->device->id] = id;
#ifdef SYNC_DEBUG
					printk(" sync_xfer=%02x\n",
					       hostdata->sync_xfer[cmd->device->id]);
#endif
					hostdata->sync_stat[cmd->device->id] =
					    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;
		}
		spin_unlock_irqrestore(&hostdata->lock, 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"))
			    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->device->id] &= ~(1 << (cmd->device->lun & 0xff));
			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.
 */
			spin_unlock_irqrestore(&hostdata->lock, flags);
			wd33c93_execute(instance);
		} else {
			printk
			    ("%02x:%02x:%02x: Unknown SEL_XFER_DONE phase!!---",
			     asr, sr, phs);
			spin_unlock_irqrestore(&hostdata->lock, flags);
		}
		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);
		spin_unlock_irqrestore(&hostdata->lock, flags);
		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;
		spin_unlock_irqrestore(&hostdata->lock, flags);
		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;
			spin_unlock_irqrestore(&hostdata->lock, flags);
			return;
		}
		DB(DB_INTR, printk("UNEXP_DISC"))
		    hostdata->connected = NULL;
		hostdata->busy[cmd->device->id] &= ~(1 << (cmd->device->lun & 0xff));
		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() */
		spin_unlock_irqrestore(&hostdata->lock, 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"))
		    if (cmd == NULL) {
			printk(" - Already disconnected! ");
			hostdata->state = S_UNCONNECTED;
		}
		switch (hostdata->state) {
		case S_PRE_CMP_DISC:
			hostdata->connected = NULL;
			hostdata->busy[cmd->device->id] &= ~(1 << (cmd->device->lun & 0xff));
			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);
			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->device->id]++;
#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.
 */
		spin_unlock_irqrestore(&hostdata->lock, flags);
		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 = (struct scsi_cmnd *) hostdata->selecting;
				hostdata->selecting = NULL;
				hostdata->busy[cmd->device->id] &= ~(1 << (cmd->device->lun & 0xff));
				cmd->host_scribble =
				    (uchar *) hostdata->input_Q;
				hostdata->input_Q = cmd;
			}
		}

		else {

			if (cmd) {
				if (phs == 0x00) {
					hostdata->busy[cmd->device->id] &=
						~(1 << (cmd->device->lun & 0xff));
					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(regs)) & 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);
				udelay(7);
				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(regs);
					if (!(asr & ASR_INT)) {
						udelay(10);
						asr = read_aux_stat(regs);
						if (!(asr & ASR_INT))
							printk
							    ("wd33c93: No int after LUN on RESEL (%02x)\n",
							     asr);
					}
					sr = read_wd33c93(regs, WD_SCSI_STATUS);
					udelay(7);
					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 = (struct scsi_cmnd *) hostdata->disconnected_Q;
		patch = NULL;
		while (cmd) {
			if (id == cmd->device->id && lun == (u8)cmd->device->lun)
				break;
			patch = cmd;
			cmd = (struct 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, (u8)lun);
			spin_unlock_irqrestore(&hostdata->lock, flags);
			return;
		}

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

		if (patch)
			patch->host_scribble = cmd->host_scribble;
		else
			hostdata->disconnected_Q =
			    (struct 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 (cmd->sc_data_direction == DMA_TO_DEVICE)
			write_wd33c93(regs, WD_DESTINATION_ID, cmd->device->id);
		else
			write_wd33c93(regs, WD_DESTINATION_ID,
				      cmd->device->id | 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;

		    spin_unlock_irqrestore(&hostdata->lock, flags);
		break;

	default:
		printk("--UNKNOWN INTERRUPT:%02x:%02x:%02x--", asr, sr, phs);
		spin_unlock_irqrestore(&hostdata->lock, flags);
	}

	DB(DB_INTR, printk("} "))

}

static 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(regs) & 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(regs) & 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, 0, hostdata->sx_table));
	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(regs) & 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;

	if (hostdata->chip != C_WD33C93B)	/* Fast SCSI unavailable */
		hostdata->fast = 0;

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

int
wd33c93_host_reset(struct scsi_cmnd * SCpnt)
{
	struct Scsi_Host *instance;
	struct WD33C93_hostdata *hostdata;
	int i;

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

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

	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,
					0, hostdata->sx_table);
		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…