path: root/drivers/scsi/NCR53C9x.c

/* NCR53C9x.c:  Generic SCSI driver code for NCR53C9x chips.
 *
 * Originally esp.c : EnhancedScsiProcessor Sun SCSI driver code.
 *
 * Copyright (C) 1995, 1998 David S. Miller (davem@caip.rutgers.edu)
 *
 * Most DMA dependencies put in driver specific files by 
 * Jesper Skov (jskov@cygnus.co.uk)
 *
 * Set up to use esp_read/esp_write (preprocessor macros in NCR53c9x.h) by
 * Tymm Twillman (tymm@coe.missouri.edu)
 */

/* TODO:
 *
 * 1) Maybe disable parity checking in config register one for SCSI1
 *    targets.  (Gilmore says parity error on the SBus can lock up
 *    old sun4c's)
 * 2) Add support for DMA2 pipelining.
 * 3) Add tagged queueing.
 * 4) Maybe change use of "esp" to something more "NCR"'ish.
 */

#include <linux/module.h>

#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/blkdev.h>
#include <linux/interrupt.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/init.h>

#include "scsi.h"
#include <scsi/scsi_host.h>
#include "NCR53C9x.h"

#include <asm/system.h>
#include <asm/ptrace.h>
#include <asm/pgtable.h>
#include <asm/io.h>
#include <asm/irq.h>

/* Command phase enumeration. */
enum {
	not_issued    = 0x00,  /* Still in the issue_SC queue.          */

	/* Various forms of selecting a target. */
#define in_slct_mask    0x10
	in_slct_norm  = 0x10,  /* ESP is arbitrating, normal selection  */
	in_slct_stop  = 0x11,  /* ESP will select, then stop with IRQ   */
	in_slct_msg   = 0x12,  /* select, then send a message           */
	in_slct_tag   = 0x13,  /* select and send tagged queue msg      */
	in_slct_sneg  = 0x14,  /* select and acquire sync capabilities  */

	/* Any post selection activity. */
#define in_phases_mask  0x20
	in_datain     = 0x20,  /* Data is transferring from the bus     */
	in_dataout    = 0x21,  /* Data is transferring to the bus       */
	in_data_done  = 0x22,  /* Last DMA data operation done (maybe)  */
	in_msgin      = 0x23,  /* Eating message from target            */
	in_msgincont  = 0x24,  /* Eating more msg bytes from target     */
	in_msgindone  = 0x25,  /* Decide what to do with what we got    */
	in_msgout     = 0x26,  /* Sending message to target             */
	in_msgoutdone = 0x27,  /* Done sending msg out                  */
	in_cmdbegin   = 0x28,  /* Sending cmd after abnormal selection  */
	in_cmdend     = 0x29,  /* Done sending slow cmd                 */
	in_status     = 0x2a,  /* Was in status phase, finishing cmd    */
	in_freeing    = 0x2b,  /* freeing the bus for cmd cmplt or disc */
	in_the_dark   = 0x2c,  /* Don't know what bus phase we are in   */

	/* Special states, ie. not normal bus transitions... */
#define in_spec_mask    0x80
	in_abortone   = 0x80,  /* Aborting one command currently        */
	in_abortall   = 0x81,  /* Blowing away all commands we have     */
	in_resetdev   = 0x82,  /* SCSI target reset in progress         */
	in_resetbus   = 0x83,  /* SCSI bus reset in progress            */
	in_tgterror   = 0x84,  /* Target did something stupid           */
};

enum {
	/* Zero has special meaning, see skipahead[12]. */
/*0*/	do_never,

/*1*/	do_phase_determine,
/*2*/	do_reset_bus,
/*3*/	do_reset_complete,
/*4*/	do_work_bus,
/*5*/	do_intr_end
};

/* The master ring of all esp hosts we are managing in this driver. */
static struct NCR_ESP *espchain;
int nesps = 0, esps_in_use = 0, esps_running = 0;

irqreturn_t esp_intr(int irq, void *dev_id, struct pt_regs *pregs);

/* Debugging routines */
static struct esp_cmdstrings {
	unchar cmdchar;
	char *text;
} esp_cmd_strings[] = {
	/* Miscellaneous */
	{ ESP_CMD_NULL, "ESP_NOP", },
	{ ESP_CMD_FLUSH, "FIFO_FLUSH", },
	{ ESP_CMD_RC, "RSTESP", },
	{ ESP_CMD_RS, "RSTSCSI", },
	/* Disconnected State Group */
	{ ESP_CMD_RSEL, "RESLCTSEQ", },
	{ ESP_CMD_SEL, "SLCTNATN", },
	{ ESP_CMD_SELA, "SLCTATN", },
	{ ESP_CMD_SELAS, "SLCTATNSTOP", },
	{ ESP_CMD_ESEL, "ENSLCTRESEL", },
	{ ESP_CMD_DSEL, "DISSELRESEL", },
	{ ESP_CMD_SA3, "SLCTATN3", },
	{ ESP_CMD_RSEL3, "RESLCTSEQ", },
	/* Target State Group */
	{ ESP_CMD_SMSG, "SNDMSG", },
	{ ESP_CMD_SSTAT, "SNDSTATUS", },
	{ ESP_CMD_SDATA, "SNDDATA", },
	{ ESP_CMD_DSEQ, "DISCSEQ", },
	{ ESP_CMD_TSEQ, "TERMSEQ", },
	{ ESP_CMD_TCCSEQ, "TRGTCMDCOMPSEQ", },
	{ ESP_CMD_DCNCT, "DISC", },
	{ ESP_CMD_RMSG, "RCVMSG", },
	{ ESP_CMD_RCMD, "RCVCMD", },
	{ ESP_CMD_RDATA, "RCVDATA", },
	{ ESP_CMD_RCSEQ, "RCVCMDSEQ", },
	/* Initiator State Group */
	{ ESP_CMD_TI, "TRANSINFO", },
	{ ESP_CMD_ICCSEQ, "INICMDSEQCOMP", },
	{ ESP_CMD_MOK, "MSGACCEPTED", },
	{ ESP_CMD_TPAD, "TPAD", },
	{ ESP_CMD_SATN, "SATN", },
	{ ESP_CMD_RATN, "RATN", },
};
#define NUM_ESP_COMMANDS  ((sizeof(esp_cmd_strings)) / (sizeof(struct esp_cmdstrings)))

/* Print textual representation of an ESP command */
static inline void esp_print_cmd(unchar espcmd)
{
	unchar dma_bit = espcmd & ESP_CMD_DMA;
	int i;

	espcmd &= ~dma_bit;
	for(i=0; i<NUM_ESP_COMMANDS; i++)
		if(esp_cmd_strings[i].cmdchar == espcmd)
			break;
	if(i==NUM_ESP_COMMANDS)
		printk("ESP_Unknown");
	else
		printk("%s%s", esp_cmd_strings[i].text,
		       ((dma_bit) ? "+DMA" : ""));
}

/* Print the status register's value */
static inline void esp_print_statreg(unchar statreg)
{
	unchar phase;

	printk("STATUS<");
	phase = statreg & ESP_STAT_PMASK;
	printk("%s,", (phase == ESP_DOP ? "DATA-OUT" :
		       (phase == ESP_DIP ? "DATA-IN" :
			(phase == ESP_CMDP ? "COMMAND" :
			 (phase == ESP_STATP ? "STATUS" :
			  (phase == ESP_MOP ? "MSG-OUT" :
			   (phase == ESP_MIP ? "MSG_IN" :
			    "unknown")))))));
	if(statreg & ESP_STAT_TDONE)
		printk("TRANS_DONE,");
	if(statreg & ESP_STAT_TCNT)
		printk("TCOUNT_ZERO,");
	if(statreg & ESP_STAT_PERR)
		printk("P_ERROR,");
	if(statreg & ESP_STAT_SPAM)
		printk("SPAM,");
	if(statreg & ESP_STAT_INTR)
		printk("IRQ,");
	printk(">");
}

/* Print the interrupt register's value */
static inline void esp_print_ireg(unchar intreg)
{
	printk("INTREG< ");
	if(intreg & ESP_INTR_S)
		printk("SLCT_NATN ");
	if(intreg & ESP_INTR_SATN)
		printk("SLCT_ATN ");
	if(intreg & ESP_INTR_RSEL)
		printk("RSLCT ");
	if(intreg & ESP_INTR_FDONE)
		printk("FDONE ");
	if(intreg & ESP_INTR_BSERV)
		printk("BSERV ");
	if(intreg & ESP_INTR_DC)
		printk("DISCNCT ");
	if(intreg & ESP_INTR_IC)
		printk("ILL_CMD ");
	if(intreg & ESP_INTR_SR)
		printk("SCSI_BUS_RESET ");
	printk(">");
}

/* Print the sequence step registers contents */
static inline void esp_print_seqreg(unchar stepreg)
{
	stepreg &= ESP_STEP_VBITS;
	printk("STEP<%s>",
	       (stepreg == ESP_STEP_ASEL ? "SLCT_ARB_CMPLT" :
		(stepreg == ESP_STEP_SID ? "1BYTE_MSG_SENT" :
		 (stepreg == ESP_STEP_NCMD ? "NOT_IN_CMD_PHASE" :
		  (stepreg == ESP_STEP_PPC ? "CMD_BYTES_LOST" :
		   (stepreg == ESP_STEP_FINI4 ? "CMD_SENT_OK" :
		    "UNKNOWN"))))));
}

static char *phase_string(int phase)
{
	switch(phase) {
	case not_issued:
		return "UNISSUED";
	case in_slct_norm:
		return "SLCTNORM";
	case in_slct_stop:
		return "SLCTSTOP";
	case in_slct_msg:
		return "SLCTMSG";
	case in_slct_tag:
		return "SLCTTAG";
	case in_slct_sneg:
		return "SLCTSNEG";
	case in_datain:
		return "DATAIN";
	case in_dataout:
		return "DATAOUT";
	case in_data_done:
		return "DATADONE";
	case in_msgin:
		return "MSGIN";
	case in_msgincont:
		return "MSGINCONT";
	case in_msgindone:
		return "MSGINDONE";
	case in_msgout:
		return "MSGOUT";
	case in_msgoutdone:
		return "MSGOUTDONE";
	case in_cmdbegin:
		return "CMDBEGIN";
	case in_cmdend:
		return "CMDEND";
	case in_status:
		return "STATUS";
	case in_freeing:
		return "FREEING";
	case in_the_dark:
		return "CLUELESS";
	case in_abortone:
		return "ABORTONE";
	case in_abortall:
		return "ABORTALL";
	case in_resetdev:
		return "RESETDEV";
	case in_resetbus:
		return "RESETBUS";
	case in_tgterror:
		return "TGTERROR";
	default:
		return "UNKNOWN";
	};
}

#ifdef DEBUG_STATE_MACHINE
static inline void esp_advance_phase(Scsi_Cmnd *s, int newphase)
{
	ESPLOG(("<%s>", phase_string(newphase)));
	s->SCp.sent_command = s->SCp.phase;
	s->SCp.phase = newphase;
}
#else
#define esp_advance_phase(__s, __newphase) \
	(__s)->SCp.sent_command = (__s)->SCp.phase; \
	(__s)->SCp.phase = (__newphase);
#endif

#ifdef DEBUG_ESP_CMDS
static inline void esp_cmd(struct NCR_ESP *esp, struct ESP_regs *eregs,
			   unchar cmd)
{
	esp->espcmdlog[esp->espcmdent] = cmd;
	esp->espcmdent = (esp->espcmdent + 1) & 31;
	esp_write(eregs->esp_cmnd, cmd);
}
#else
#define esp_cmd(__esp, __eregs, __cmd)	esp_write((__eregs)->esp_cmnd, (__cmd))
#endif

/* How we use the various Linux SCSI data structures for operation.
 *
 * struct scsi_cmnd:
 *
 *   We keep track of the syncronous capabilities of a target
 *   in the device member, using sync_min_period and
 *   sync_max_offset.  These are the values we directly write
 *   into the ESP registers while running a command.  If offset
 *   is zero the ESP will use asynchronous transfers.
 *   If the borken flag is set we assume we shouldn't even bother
 *   trying to negotiate for synchronous transfer as this target
 *   is really stupid.  If we notice the target is dropping the
 *   bus, and we have been allowing it to disconnect, we clear
 *   the disconnect flag.
 */

/* Manipulation of the ESP command queues.  Thanks to the aha152x driver
 * and its author, Juergen E. Fischer, for the methods used here.
 * Note that these are per-ESP queues, not global queues like
 * the aha152x driver uses.
 */
static inline void append_SC(Scsi_Cmnd **SC, Scsi_Cmnd *new_SC)
{
	Scsi_Cmnd *end;

	new_SC->host_scribble = (unsigned char *) NULL;
	if(!*SC)
		*SC = new_SC;
	else {
		for(end=*SC;end->host_scribble;end=(Scsi_Cmnd *)end->host_scribble)
			;
		end->host_scribble = (unsigned char *) new_SC;
	}
}

static inline void prepend_SC(Scsi_Cmnd **SC, Scsi_Cmnd *new_SC)
{
	new_SC->host_scribble = (unsigned char *) *SC;
	*SC = new_SC;
}

static inline Scsi_Cmnd *remove_first_SC(Scsi_Cmnd **SC)
{
	Scsi_Cmnd *ptr;

	ptr = *SC;
	if(ptr)
		*SC = (Scsi_Cmnd *) (*SC)->host_scribble;
	return ptr;
}

static inline Scsi_Cmnd *remove_SC(Scsi_Cmnd **SC, int target, int lun)
{
	Scsi_Cmnd *ptr, *prev;

	for(ptr = *SC, prev = NULL;
	    ptr && ((ptr->device->id != target) || (ptr->device->lun != lun));
	    prev = ptr, ptr = (Scsi_Cmnd *) ptr->host_scribble)
		;
	if(ptr) {
		if(prev)
			prev->host_scribble=ptr->host_scribble;
		else
			*SC=(Scsi_Cmnd *)ptr->host_scribble;
	}
	return ptr;
}

/* Resetting various pieces of the ESP scsi driver chipset */

/* Reset the ESP chip, _not_ the SCSI bus. */
static void esp_reset_esp(struct NCR_ESP *esp, struct ESP_regs *eregs)
{
	int family_code, version, i;
	volatile int trash;

	/* Now reset the ESP chip */
	esp_cmd(esp, eregs, ESP_CMD_RC);
	esp_cmd(esp, eregs, ESP_CMD_NULL | ESP_CMD_DMA);
	if(esp->erev == fast)
		esp_write(eregs->esp_cfg2, ESP_CONFIG2_FENAB);
	esp_cmd(esp, eregs, ESP_CMD_NULL | ESP_CMD_DMA);

	/* This is the only point at which it is reliable to read
	 * the ID-code for a fast ESP chip variant.
	 */
	esp->max_period = ((35 * esp->ccycle) / 1000);
	if(esp->erev == fast) {
		char *erev2string[] = {
			"Emulex FAS236",
			"Emulex FPESP100A",
			"fast",
			"QLogic FAS366",
			"Emulex FAS216",
			"Symbios Logic 53CF9x-2",
			"unknown!"
		};
			
		version = esp_read(eregs->esp_uid);
		family_code = (version & 0xf8) >> 3;
		if(family_code == 0x02) {
		        if ((version & 7) == 2)
			        esp->erev = fas216;	
                        else
			        esp->erev = fas236;
		} else if(family_code == 0x0a)
			esp->erev = fas366; /* Version is usually '5'. */
		else if(family_code == 0x00) {
			if ((version & 7) == 2)
				esp->erev = fas100a; /* NCR53C9X */
			else
				esp->erev = espunknown;
		} else if(family_code == 0x14) {
			if ((version & 7) == 2)
				esp->erev = fsc;
		        else
				esp->erev = espunknown;
		} else if(family_code == 0x00) {
			if ((version & 7) == 2)
				esp->erev = fas100a; /* NCR53C9X */
			else
				esp->erev = espunknown;
		} else
			esp->erev = espunknown;
		ESPLOG(("esp%d: FAST chip is %s (family=%d, version=%d)\n",
			esp->esp_id, erev2string[esp->erev - fas236],
			family_code, (version & 7)));

		esp->min_period = ((4 * esp->ccycle) / 1000);
	} else {
		esp->min_period = ((5 * esp->ccycle) / 1000);
	}

	/* Reload the configuration registers */
	esp_write(eregs->esp_cfact, esp->cfact);
	esp->prev_stp = 0;
	esp_write(eregs->esp_stp, 0);
	esp->prev_soff = 0;
	esp_write(eregs->esp_soff, 0);
	esp_write(eregs->esp_timeo, esp->neg_defp);
	esp->max_period = (esp->max_period + 3)>>2;
	esp->min_period = (esp->min_period + 3)>>2;

	esp_write(eregs->esp_cfg1, esp->config1);
	switch(esp->erev) {
	case esp100:
		/* nothing to do */
		break;
	case esp100a:
		esp_write(eregs->esp_cfg2, esp->config2);
		break;
	case esp236:
		/* Slow 236 */
		esp_write(eregs->esp_cfg2, esp->config2);
		esp->prev_cfg3 = esp->config3[0];
		esp_write(eregs->esp_cfg3, esp->prev_cfg3);
		break;
	case fas366:
		panic("esp: FAS366 support not present, please notify "
		      "jongk@cs.utwente.nl");
		break;
	case fas216:
	case fas236:
	case fsc:
		/* Fast ESP variants */
		esp_write(eregs->esp_cfg2, esp->config2);
		for(i=0; i<8; i++)
			esp->config3[i] |= ESP_CONFIG3_FCLK;
		esp->prev_cfg3 = esp->config3[0];
		esp_write(eregs->esp_cfg3, esp->prev_cfg3);
		if(esp->diff)
			esp->radelay = 0;
		else
			esp->radelay = 16;
		/* Different timeout constant for these chips */
		esp->neg_defp =
			FSC_NEG_DEFP(esp->cfreq,
				     (esp->cfact == ESP_CCF_F0 ?
				      ESP_CCF_F7 + 1 : esp->cfact));
		esp_write(eregs->esp_timeo, esp->neg_defp);
		/* Enable Active Negotiation if possible */
		if((esp->erev == fsc) && !esp->diff)
			esp_write(eregs->esp_cfg4, ESP_CONFIG4_EAN);
		break;
	case fas100a:
		/* Fast 100a */
		esp_write(eregs->esp_cfg2, esp->config2);
		for(i=0; i<8; i++)
			esp->config3[i] |= ESP_CONFIG3_FCLOCK;
		esp->prev_cfg3 = esp->config3[0];
		esp_write(eregs->esp_cfg3, esp->prev_cfg3);
		esp->radelay = 32;
		break;
	default:
		panic("esp: what could it be... I wonder...");
		break;
	};

	/* Eat any bitrot in the chip */
	trash = esp_read(eregs->esp_intrpt);
	udelay(100);
}

/* This places the ESP into a known state at boot time. */
void esp_bootup_reset(struct NCR_ESP *esp, struct ESP_regs *eregs)
{
	volatile unchar trash;

	/* Reset the DMA */
	if(esp->dma_reset)
		esp->dma_reset(esp);

	/* Reset the ESP */
	esp_reset_esp(esp, eregs);

	/* Reset the SCSI bus, but tell ESP not to generate an irq */
	esp_write(eregs->esp_cfg1, (esp_read(eregs->esp_cfg1) | ESP_CONFIG1_SRRDISAB));
	esp_cmd(esp, eregs, ESP_CMD_RS);
	udelay(400);
	esp_write(eregs->esp_cfg1, esp->config1);

	/* Eat any bitrot in the chip and we are done... */
	trash = esp_read(eregs->esp_intrpt);
}

/* Allocate structure and insert basic data such as SCSI chip frequency
 * data and a pointer to the device
 */
struct NCR_ESP* esp_allocate(struct scsi_host_template *tpnt, void *esp_dev)
{
	struct NCR_ESP *esp, *elink;
	struct Scsi_Host *esp_host;

	esp_host = scsi_register(tpnt, sizeof(struct NCR_ESP));
	if(!esp_host)
		panic("Cannot register ESP SCSI host");
	esp = (struct NCR_ESP *) esp_host->hostdata;
	if(!esp)
		panic("No esp in hostdata");
	esp->ehost = esp_host;
	esp->edev = esp_dev;
	esp->esp_id = nesps++;

	/* Set bitshift value (only used on Amiga with multiple ESPs) */
	esp->shift = 2;

	/* Put into the chain of esp chips detected */
	if(espchain) {
		elink = espchain;
		while(elink->next) elink = elink->next;
		elink->next = esp;
	} else {
		espchain = esp;
	}
	esp->next = NULL;

	return esp;
}

void esp_deallocate(struct NCR_ESP *esp)
{
	struct NCR_ESP *elink;

	if(espchain == esp) {
		espchain = NULL;
	} else {
		for(elink = espchain; elink && (elink->next != esp); elink = elink->next);
		if(elink) 
			elink->next = esp->next;
	}
	nesps--;
}

/* Complete initialization of ESP structure and device
 * Caller must have initialized appropriate parts of the ESP structure
 * between the call to esp_allocate and this function.
 */
void esp_initialize(struct NCR_ESP *esp)
{
	struct ESP_regs *eregs = esp->eregs;
	unsigned int fmhz;
	unchar ccf;
	int i;
	
	/* Check out the clock properties of the chip. */

	/* This is getting messy but it has to be done
	 * correctly or else you get weird behavior all
	 * over the place.  We are trying to basically
	 * figure out three pieces of information.
	 *
	 * a) Clock Conversion Factor
	 *
	 *    This is a representation of the input
	 *    crystal clock frequency going into the
	 *    ESP on this machine.  Any operation whose
	 *    timing is longer than 400ns depends on this
	 *    value being correct.  For example, you'll
	 *    get blips for arbitration/selection during
	 *    high load or with multiple targets if this
	 *    is not set correctly.
	 *
	 * b) Selection Time-Out
	 *
	 *    The ESP isn't very bright and will arbitrate
	 *    for the bus and try to select a target
	 *    forever if you let it.  This value tells
	 *    the ESP when it has taken too long to
	 *    negotiate and that it should interrupt
	 *    the CPU so we can see what happened.
	 *    The value is computed as follows (from
	 *    NCR/Symbios chip docs).
	 *
	 *          (Time Out Period) *  (Input Clock)
	 *    STO = ----------------------------------
	 *          (8192) * (Clock Conversion Factor)
	 *
	 *    You usually want the time out period to be
	 *    around 250ms, I think we'll set it a little
	 *    bit higher to account for fully loaded SCSI
	 *    bus's and slow devices that don't respond so
	 *    quickly to selection attempts. (yeah, I know
	 *    this is out of spec. but there is a lot of
	 *    buggy pieces of firmware out there so bite me)
	 *
	 * c) Imperical constants for synchronous offset
	 *    and transfer period register values
	 *
	 *    This entails the smallest and largest sync
	 *    period we could ever handle on this ESP.
	 */
	
	fmhz = esp->cfreq;

	if(fmhz <= (5000000))
		ccf = 0;
	else
		ccf = (((5000000 - 1) + (fmhz))/(5000000));
	if(!ccf || ccf > 8) {
		/* If we can't find anything reasonable,
		 * just assume 20MHZ.  This is the clock
		 * frequency of the older sun4c's where I've
		 * been unable to find the clock-frequency
		 * PROM property.  All other machines provide
		 * useful values it seems.
		 */
		ccf = ESP_CCF_F4;
		fmhz = (20000000);
	}
	if(ccf==(ESP_CCF_F7+1))
		esp->cfact = ESP_CCF_F0;
	else if(ccf == ESP_CCF_NEVER)
		esp->cfact = ESP_CCF_F2;
	else
		esp->cfact = ccf;
	esp->cfreq = fmhz;
	esp->ccycle = ESP_MHZ_TO_CYCLE(fmhz);
	esp->ctick = ESP_TICK(ccf, esp->ccycle);
	esp->neg_defp = ESP_NEG_DEFP(fmhz, ccf);
	esp->sync_defp = SYNC_DEFP_SLOW;

	printk("SCSI ID %d Clk %dMHz CCF=%d TOut %d ",
	       esp->scsi_id, (esp->cfreq / 1000000),
	       ccf, (int) esp->neg_defp);

	/* Fill in ehost data */
	esp->ehost->base = (unsigned long)eregs;
	esp->ehost->this_id = esp->scsi_id;
	esp->ehost->irq = esp->irq;

	/* SCSI id mask */
	esp->scsi_id_mask = (1 << esp->scsi_id);

	/* Probe the revision of this esp */
	esp->config1 = (ESP_CONFIG1_PENABLE | (esp->scsi_id & 7));
	esp->config2 = (ESP_CONFIG2_SCSI2ENAB | ESP_CONFIG2_REGPARITY);
	esp_write(eregs->esp_cfg2, esp->config2);
	if((esp_read(eregs->esp_cfg2) & ~(ESP_CONFIG2_MAGIC)) !=
	   (ESP_CONFIG2_SCSI2ENAB | ESP_CONFIG2_REGPARITY)) {
		printk("NCR53C90(esp100)\n");
		esp->erev = esp100;
	} else {
		esp->config2 = 0;
		esp_write(eregs->esp_cfg2, 0);
		esp_write(eregs->esp_cfg3, 5);
		if(esp_read(eregs->esp_cfg3) != 5) {
			printk("NCR53C90A(esp100a)\n");
			esp->erev = esp100a;
		} else {
			int target;

			for(target=0; target<8; target++)
				esp->config3[target] = 0;
			esp->prev_cfg3 = 0;
			esp_write(eregs->esp_cfg3, 0);
			if(ccf > ESP_CCF_F5) {
				printk("NCR53C9XF(espfast)\n");
				esp->erev = fast;
				esp->sync_defp = SYNC_DEFP_FAST;
			} else {
				printk("NCR53C9x(esp236)\n");
				esp->erev = esp236;
			}
		}
	}				

	/* Initialize the command queues */
	esp->current_SC = NULL;
	esp->disconnected_SC = NULL;
	esp->issue_SC = NULL;

	/* Clear the state machines. */
	esp->targets_present = 0;
	esp->resetting_bus = 0;
	esp->snip = 0;

	init_waitqueue_head(&esp->reset_queue);

	esp->fas_premature_intr_workaround = 0;
	for(i = 0; i < 32; i++)
		esp->espcmdlog[i] = 0;
	esp->espcmdent = 0;
	for(i = 0; i < 16; i++) {
		esp->cur_msgout[i] = 0;
		esp->cur_msgin[i] = 0;
	}
	esp->prevmsgout = esp->prevmsgin = 0;
	esp->msgout_len = esp->msgin_len = 0;

	/* Clear the one behind caches to hold unmatchable values. */
	esp->prev_soff = esp->prev_stp = esp->prev_cfg3 = 0xff;

	/* Reset the thing before we try anything... */
	esp_bootup_reset(esp, eregs);

	esps_in_use++;
}

/* The info function will return whatever useful
 * information the developer sees fit.  If not provided, then
 * the name field will be used instead.
 */
const char *esp_info(struct Scsi_Host *host)
{
	struct NCR_ESP *esp;

	esp = (struct NCR_ESP *) host->hostdata;
	switch(esp->erev) {
	case esp100:
		return "ESP100 (NCR53C90)";
	case esp100a:
		return "ESP100A (NCR53C90A)";
	case esp236:
		return "ESP236 (NCR53C9x)";
	case fas216:
		return "Emulex FAS216";
	case fas236:
		return "Emulex FAS236";
	case fas366:
		return "QLogic FAS366";
	case fas100a:
		return "FPESP100A";
	case fsc:
		return "Symbios Logic 53CF9x-2";
	default:
		panic("Bogon ESP revision");
	};
}

/* From Wolfgang Stanglmeier's NCR scsi driver. */
struct info_str
{
	char *buffer;
	int length;
	int offset;
	int pos;
};

static void copy_mem_info(struct info_str *info, char *data, int len)
{
	if (info->pos + len > info->length)
		len = info->length - info->pos;

	if (info->pos + len < info->offset) {
		info->pos += len;
		return;
	}
	if (info->pos < info->offset) {
		data += (info->offset - info->pos);
		len  -= (info->offset - info->pos);
	}

	if (len > 0) {
		memcpy(info->buffer + info->pos, data, len);
		info->pos += len;
	}
}

static int copy_info(struct info_str *info, char *fmt, ...)
{
	va_list args;
	char buf[81];
	int len;

	va_start(args, fmt);
	len = vsprintf(buf, fmt, args);
	va_end(args);

	copy_mem_info(info, buf, len);
	return len;
}

static int esp_host_info(struct NCR_ESP *esp, char *ptr, off_t offset, int len)
{
	struct scsi_device *sdev;
	struct info_str info;
	int i;

	info.buffer	= ptr;
	info.length	= len;
	info.offset	= offset;
	info.pos	= 0;

	copy_info(&info, "ESP Host Adapter:\n");
	copy_info(&info, "\tESP Model\t\t");
	switch(esp->erev) {
	case esp100:
		copy_info(&info, "ESP100 (NCR53C90)\n");
		break;
	case esp100a:
		copy_info(&info, "ESP100A (NCR53C90A)\n");
		break;
	case esp236:
		copy_info(&info, "ESP236 (NCR53C9x)\n");
		break;
	case fas216:
		copy_info(&info, "Emulex FAS216\n");
		break;
	case fas236:
		copy_info(&info, "Emulex FAS236\n");
		break;
	case fas100a:
		copy_info(&info, "FPESP100A\n");
		break;
	case fast:
		copy_info(&info, "Generic FAST\n");
		break;
	case fas366:
		copy_info(&info, "QLogic FAS366\n");
		break;
	case fsc:
		copy_info(&info, "Symbios Logic 53C9x-2\n");
		break;
	case espunknown:
	default:
		copy_info(&info, "Unknown!\n");
		break;
	};
	copy_info(&info, "\tLive Targets\t\t[ ");
	for(i = 0; i < 15; i++) {
		if(esp->targets_present & (1 << i))
			copy_info(&info, "%d ", i);
	}
	copy_info(&info, "]\n\n");
	
	/* Now describe the state of each existing target. */
	copy_info(&info, "Target #\tconfig3\t\tSync Capabilities\tDisconnect\n");

	shost_for_each_device(sdev, esp->ehost) {
		struct esp_device *esp_dev = sdev->hostdata;
		uint id = sdev->id;

		if (!(esp->targets_present & (1 << id)))
			continue;

		copy_info(&info, "%d\t\t", id);
		copy_info(&info, "%08lx\t", esp->config3[id]);
		copy_info(&info, "[%02lx,%02lx]\t\t\t",
			esp_dev->sync_max_offset,
			esp_dev->sync_min_period);
		copy_info(&info, "%s\n", esp_dev->disconnect ? "yes" : "no");
	}

	return info.pos > info.offset? info.pos - info.offset : 0;
}

/* ESP proc filesystem code. */
int esp_proc_info(struct Scsi_Host *shost, char *buffer, char **start, off_t offset, int length,
		  int inout)
{
	struct NCR_ESP *esp = (struct NCR_ESP *)shost->hostdata;

	if(inout)
		return -EINVAL; /* not yet */
	if(start)
		*start = buffer;
	return esp_host_info(esp, buffer, offset, length);
}

static void esp_get_dmabufs(struct NCR_ESP *esp, Scsi_Cmnd *sp)
{
	if(sp->use_sg == 0) {
		sp->SCp.this_residual = sp->request_bufflen;
		sp->SCp.buffer = (struct scatterlist *) sp->request_buffer;
		sp->SCp.buffers_residual = 0;
		if (esp->dma_mmu_get_scsi_one)
			esp->dma_mmu_get_scsi_one(esp, sp);
		else
			sp->SCp.ptr =
				(char *) virt_to_phys(sp->request_buffer);
	} else {
		sp->SCp.buffer = (struct scatterlist *) sp->request_buffer;
		sp->SCp.buffers_residual = sp->use_sg - 1;
		sp->SCp.this_residual = sp->SCp.buffer->length;
		if (esp->dma_mmu_get_scsi_sgl)
			esp->dma_mmu_get_scsi_sgl(esp, sp);
		else
			sp->SCp.ptr =
				(char *) virt_to_phys((page_address(sp->SCp.buffer->page) + sp->SCp.buffer->offset));
	}
}

static void esp_release_dmabufs(struct NCR_ESP *esp, Scsi_Cmnd *sp)
{
	if(sp->use_sg == 0) {
		if (esp->dma_mmu_release_scsi_one)
			esp->dma_mmu_release_scsi_one(esp, sp);
	} else {
		if (esp->dma_mmu_release_scsi_sgl)
			esp->dma_mmu_release_scsi_sgl(esp, sp);
	}
}

static void esp_restore_pointers(struct NCR_ESP *esp, Scsi_Cmnd *sp)
{
	struct esp_pointers *ep = &esp->data_pointers[scmd_id(sp)];

	sp->SCp.ptr = ep->saved_ptr;
	sp->SCp.buffer = ep->saved_buffer;
	sp->SCp.this_residual = ep->saved_this_residual;
	sp->SCp.buffers_residual = ep->saved_buffers_residual;
}

static void esp_save_pointers(struct NCR_ESP *esp, Scsi_Cmnd *sp)
{
	struct esp_pointers *ep = &esp->data_pointers[scmd_id(sp)];

	ep->saved_ptr = sp->SCp.ptr;
	ep->saved_buffer = sp->SCp.buffer;
	ep->saved_this_residual = sp->SCp.this_residual;
	ep->saved_buffers_residual = sp->SCp.buffers_residual;
}

/* Some rules:
 *
 *   1) Never ever panic while something is live on the bus.
 *      If there is to be any chance of syncing the disks this
 *      rule is to be obeyed.
 *
 *   2) Any target that causes a foul condition will no longer
 *      have synchronous transfers done to it, no questions
 *      asked.
 *
 *   3) Keep register accesses to a minimum.  Think about some
 *      day when we have Xbus machines this is running on and
 *      the ESP chip is on the other end of the machine on a
 *      different board from the cpu where this is running.
 */

/* Fire off a command.  We assume the bus is free and that the only
 * case where we could see an interrupt is where we have disconnected
 * commands active and they are trying to reselect us.
 */
static inline void esp_check_cmd(struct NCR_ESP *esp, Scsi_Cmnd *sp)
{
	switch(sp->cmd_len) {
	case 6:
	case 10:
	case 12:
		esp->esp_slowcmd = 0;
		break;

	default:
		esp->esp_slowcmd = 1;
		esp->esp_scmdleft = sp->cmd_len;
		esp->esp_scmdp = &sp->cmnd[0];
		break;
	};
}

static inline void build_sync_nego_msg(struct NCR_ESP *esp, int period, int offset)
{
	esp->cur_msgout[0] = EXTENDED_MESSAGE;
	esp->cur_msgout[1] = 3;
	esp->cur_msgout[2] = EXTENDED_SDTR;
	esp->cur_msgout[3] = period;
	esp->cur_msgout[4] = offset;
	esp->msgout_len = 5;
}

static void esp_exec_cmd(struct NCR_ESP *esp)
{
	struct ESP_regs *eregs = esp->eregs;
	struct esp_device *esp_dev;
	Scsi_Cmnd *SCptr;
	struct scsi_device *SDptr;
	volatile unchar *cmdp = esp->esp_command;
	unsigned char the_esp_command;
	int lun, target;
	int i;

	/* Hold off if we have disconnected commands and
	 * an IRQ is showing...
	 */
	if(esp->disconnected_SC && esp->dma_irq_p(esp))
		return;

	/* Grab first member of the issue queue. */
	SCptr = esp->current_SC = remove_first_SC(&esp->issue_SC);

	/* Safe to panic here because current_SC is null. */
	if(!SCptr)
		panic("esp: esp_exec_cmd and issue queue is NULL");

	SDptr = SCptr->device;
	esp_dev = SDptr->hostdata;
	lun = SCptr->device->lun;
	target = SCptr->device->id;

	esp->snip = 0;
	esp->msgout_len = 0;

	/* Send it out whole, or piece by piece?   The ESP
	 * only knows how to automatically send out 6, 10,
	 * and 12 byte commands.  I used to think that the
	 * Linux SCSI code would never throw anything other
	 * than that to us, but then again there is the
	 * SCSI generic driver which can send us anything.
	 */
	esp_check_cmd(esp, SCptr);

	/* If arbitration/selection is successful, the ESP will leave
	 * ATN asserted, causing the target to go into message out
	 * phase.  The ESP will feed the target the identify and then
	 * the target can only legally go to one of command,
	 * datain/out, status, or message in phase, or stay in message
	 * out phase (should we be trying to send a sync negotiation
	 * message after the identify).  It is not allowed to drop
	 * BSY, but some buggy targets do and we check for this
	 * condition in the selection complete code.  Most of the time
	 * we'll make the command bytes available to the ESP and it
	 * will not interrupt us until it finishes command phase, we
	 * cannot do this for command sizes the ESP does not
	 * understand and in this case we'll get interrupted right
	 * when the target goes into command phase.
	 *
	 * It is absolutely _illegal_ in the presence of SCSI-2 devices
	 * to use the ESP select w/o ATN command.  When SCSI-2 devices are
	 * present on the bus we _must_ always go straight to message out
	 * phase with an identify message for the target.  Being that
	 * selection attempts in SCSI-1 w/o ATN was an option, doing SCSI-2
	 * selections should not confuse SCSI-1 we hope.
	 */

	if(esp_dev->sync) {
		/* this targets sync is known */
#ifdef CONFIG_SCSI_MAC_ESP
do_sync_known:
#endif
		if(esp_dev->disconnect)
			*cmdp++ = IDENTIFY(1, lun);
		else
			*cmdp++ = IDENTIFY(0, lun);

		if(esp->esp_slowcmd) {
			the_esp_command = (ESP_CMD_SELAS | ESP_CMD_DMA);
			esp_advance_phase(SCptr, in_slct_stop);
		} else {
			the_esp_command = (ESP_CMD_SELA | ESP_CMD_DMA);
			esp_advance_phase(SCptr, in_slct_norm);
		}
	} else if(!(esp->targets_present & (1<<target)) || !(esp_dev->disconnect)) {
		/* After the bootup SCSI code sends both the
		 * TEST_UNIT_READY and INQUIRY commands we want
		 * to at least attempt allowing the device to
		 * disconnect.
		 */
		ESPMISC(("esp: Selecting device for first time. target=%d "
			 "lun=%d\n", target, SCptr->device->lun));
		if(!SDptr->borken && !esp_dev->disconnect)
			esp_dev->disconnect = 1;

		*cmdp++ = IDENTIFY(0, lun);
		esp->prevmsgout = NOP;
		esp_advance_phase(SCptr, in_slct_norm);
		the_esp_command = (ESP_CMD_SELA | ESP_CMD_DMA);

		/* Take no chances... */
		esp_dev->sync_max_offset = 0;
		esp_dev->sync_min_period = 0;
	} else {
		int toshiba_cdrom_hwbug_wkaround = 0;

#ifdef CONFIG_SCSI_MAC_ESP
		/* Never allow synchronous transfers (disconnect OK) on
		 * Macintosh. Well, maybe later when we figured out how to 
		 * do DMA on the machines that support it ...
		 */
		esp_dev->disconnect = 1;
		esp_dev->sync_max_offset = 0;
		esp_dev->sync_min_period = 0;
		esp_dev->sync = 1;
		esp->snip = 0;
		goto do_sync_known;
#endif
		/* We've talked to this guy before,
		 * but never negotiated.  Let's try
		 * sync negotiation.
		 */
		if(!SDptr->borken) {
			if((SDptr->type == TYPE_ROM) &&
			   (!strncmp(SDptr->vendor, "TOSHIBA", 7))) {
				/* Nice try sucker... */
				ESPMISC(("esp%d: Disabling sync for buggy "
					 "Toshiba CDROM.\n", esp->esp_id));
				toshiba_cdrom_hwbug_wkaround = 1;
				build_sync_nego_msg(esp, 0, 0);
			} else {
				build_sync_nego_msg(esp, esp->sync_defp, 15);
			}
		} else {
			build_sync_nego_msg(esp, 0, 0);
		}
		esp_dev->sync = 1;
		esp->snip = 1;

		/* A fix for broken SCSI1 targets, when they disconnect
		 * they lock up the bus and confuse ESP.  So disallow
		 * disconnects for SCSI1 targets for now until we
		 * find a better fix.
		 *
		 * Addendum: This is funny, I figured out what was going
		 *           on.  The blotzed SCSI1 target would disconnect,
		 *           one of the other SCSI2 targets or both would be
		 *           disconnected as well.  The SCSI1 target would
		 *           stay disconnected long enough that we start
		 *           up a command on one of the SCSI2 targets.  As
		 *           the ESP is arbitrating for the bus the SCSI1
		 *           target begins to arbitrate as well to reselect
		 *           the ESP.  The SCSI1 target refuses to drop it's
		 *           ID bit on the data bus even though the ESP is
		 *           at ID 7 and is the obvious winner for any
		 *           arbitration.  The ESP is a poor sport and refuses
		 *           to lose arbitration, it will continue indefinitely
		 *           trying to arbitrate for the bus and can only be
		 *           stopped via a chip reset or SCSI bus reset.
		 *           Therefore _no_ disconnects for SCSI1 targets
		 *           thank you very much. ;-)
		 */
		if(((SDptr->scsi_level < 3) && (SDptr->type != TYPE_TAPE)) ||
		   toshiba_cdrom_hwbug_wkaround || SDptr->borken) {
			ESPMISC((KERN_INFO "esp%d: Disabling DISCONNECT for target %d "
				 "lun %d\n", esp->esp_id, SCptr->device->id, SCptr->device->lun));
			esp_dev->disconnect = 0;
			*cmdp++ = IDENTIFY(0, lun);
		} else {
			*cmdp++ = IDENTIFY(1, lun);
		}

		/* ESP fifo is only so big...
		 * Make this look like a slow command.
		 */
		esp->esp_slowcmd = 1;
		esp->esp_scmdleft = SCptr->cmd_len;
		esp->esp_scmdp = &SCptr->cmnd[0];

		the_esp_command = (ESP_CMD_SELAS | ESP_CMD_DMA);
		esp_advance_phase(SCptr, in_slct_msg);
	}

	if(!esp->esp_slowcmd)
		for(i = 0; i < SCptr->cmd_len; i++)
			*cmdp++ = SCptr->cmnd[i];

	esp_write(eregs->esp_busid, (target & 7));
	if (esp->prev_soff != esp_dev->sync_max_offset ||
	    esp->prev_stp  != esp_dev->sync_min_period ||
	    (esp->erev > esp100a &&
	     esp->prev_cfg3 != esp->config3[target])) {
		esp->prev_soff = esp_dev->sync_max_offset;
		esp_write(eregs->esp_soff, esp->prev_soff);
		esp->prev_stp = esp_dev->sync_min_period;
		esp_write(eregs->esp_stp, esp->prev_stp); 
		if(esp->erev > esp100a) {
			esp->prev_cfg3 = esp->config3[target];
			esp_write(eregs->esp_cfg3, esp->prev_cfg3);
		}
	}
	i = (cmdp - esp->esp_command);

	/* Set up the DMA and ESP counters */
	if(esp->do_pio_cmds){
		int j = 0;

		/* 
		 * XXX MSch:
		 *
		 * It seems this is required, at least to clean up
		 * after failed commands when using PIO mode ...
		 */
		esp_cmd(esp, eregs, ESP_CMD_FLUSH);

		for(;j<i;j++)
			esp_write(eregs->esp_fdata, esp->esp_command[j]);
		the_esp_command &= ~ESP_CMD_DMA;

		/* Tell ESP to "go". */
		esp_cmd(esp, eregs, the_esp_command);
	} else {
		/* Set up the ESP counters */
		esp_write(eregs->esp_tclow, i);
		esp_write(eregs->esp_tcmed, 0);
		esp->dma_init_write(esp, esp->esp_command_dvma, i);

		/* Tell ESP to "go". */
		esp_cmd(esp, eregs, the_esp_command);
	}
}

/* Queue a SCSI command delivered from the mid-level Linux SCSI code. */
int esp_queue(Scsi_Cmnd *SCpnt, void (*done)(Scsi_Cmnd *))
{
	struct NCR_ESP *esp;

	/* Set up func ptr and initial driver cmd-phase. */
	SCpnt->scsi_done = done;
	SCpnt->SCp.phase = not_issued;

	esp = (struct NCR_ESP *) SCpnt->device->host->hostdata;

	if(esp->dma_led_on)
		esp->dma_led_on(esp);

	/* We use the scratch area. */
	ESPQUEUE(("esp_queue: target=%d lun=%d ", SCpnt->device->id, SCpnt->lun));
	ESPDISC(("N<%02x,%02x>", SCpnt->device->id, SCpnt->lun));

	esp_get_dmabufs(esp, SCpnt);
	esp_save_pointers(esp, SCpnt); /* FIXME for tag queueing */

	SCpnt->SCp.Status           = CHECK_CONDITION;
	SCpnt->SCp.Message          = 0xff;
	SCpnt->SCp.sent_command     = 0;

	/* Place into our queue. */
	if(SCpnt->cmnd[0] == REQUEST_SENSE) {
		ESPQUEUE(("RQSENSE\n"));
		prepend_SC(&esp->issue_SC, SCpnt);
	} else {
		ESPQUEUE(("\n"));
		append_SC(&esp->issue_SC, SCpnt);
	}

	/* Run it now if we can. */
	if(!esp->current_SC && !esp->resetting_bus)
		esp_exec_cmd(esp);

	return 0;
}

/* Dump driver state. */
static void esp_dump_cmd(Scsi_Cmnd *SCptr)
{
	ESPLOG(("[tgt<%02x> lun<%02x> "
		"pphase<%s> cphase<%s>]",
		SCptr->device->id, SCptr->device->lun,
		phase_string(SCptr->SCp.sent_command),
		phase_string(SCptr->SCp.phase)));
}

static void esp_dump_state(struct NCR_ESP *esp, 
			   struct ESP_regs *eregs)
{
	Scsi_Cmnd *SCptr = esp->current_SC;
#ifdef DEBUG_ESP_CMDS
	int i;
#endif

	ESPLOG(("esp%d: dumping state\n", esp->esp_id));
	
	/* Print DMA status */
	esp->dma_dump_state(esp);

	ESPLOG(("esp%d: SW [sreg<%02x> sstep<%02x> ireg<%02x>]\n",
		esp->esp_id, esp->sreg, esp->seqreg, esp->ireg));
	ESPLOG(("esp%d: HW reread [sreg<%02x> sstep<%02x> ireg<%02x>]\n",
		esp->esp_id, esp_read(eregs->esp_status), esp_read(eregs->esp_sstep),
		esp_read(eregs->esp_intrpt)));
#ifdef DEBUG_ESP_CMDS
	printk("esp%d: last ESP cmds [", esp->esp_id);
	i = (esp->espcmdent - 1) & 31;
	printk("<");
	esp_print_cmd(esp->espcmdlog[i]);
	printk(">");
	i = (i - 1) & 31;
	printk("<");
	esp_print_cmd(esp->espcmdlog[i]);
	printk(">");
	i = (i - 1) & 31;
	printk("<");
	esp_print_cmd(esp->espcmdlog[i]);
	printk(">");
	i = (i - 1) & 31;
	printk("<");
	esp_print_cmd(esp->espcmdlog[i]);
	printk(">");
	printk("]\n");
#endif /* (DEBUG_ESP_CMDS) */

	if(SCptr) {
		ESPLOG(("esp%d: current command ", esp->esp_id));
		esp_dump_cmd(SCptr);
	}
	ESPLOG(("\n"));
	SCptr = esp->disconnected_SC;
	ESPLOG(("esp%d: disconnected ", esp->esp_id));
	while(SCptr) {
		esp_dump_cmd(SCptr);
		SCptr = (Scsi_Cmnd *) SCptr->host_scribble;
	}
	ESPLOG(("\n"));
}

/* Abort a command.  The host_lock is acquired by caller. */
int esp_abort(Scsi_Cmnd *SCptr)
{
	struct NCR_ESP *esp = (struct NCR_ESP *) SCptr->device->host->hostdata;
	struct ESP_regs *eregs = esp->eregs;
	int don;

	ESPLOG(("esp%d: Aborting command\n", esp->esp_id));
	esp_dump_state(esp, eregs);

	/* Wheee, if this is the current command on the bus, the
	 * best we can do is assert ATN and wait for msgout phase.
	 * This should even fix a hung SCSI bus when we lose state
	 * in the driver and timeout because the eventual phase change
	 * will cause the ESP to (eventually) give an interrupt.
	 */
	if(esp->current_SC == SCptr) {
		esp->cur_msgout[0] = ABORT;
		esp->msgout_len = 1;
		esp->msgout_ctr = 0;
		esp_cmd(esp, eregs, ESP_CMD_SATN);
		return SUCCESS;
	}

	/* If it is still in the issue queue then we can safely
	 * call the completion routine and report abort success.
	 */
	don = esp->dma_ports_p(esp);
	if(don) {
		esp->dma_ints_off(esp);
		synchronize_irq(esp->irq);
	}
	if(esp->issue_SC) {
		Scsi_Cmnd **prev, *this;
		for(prev = (&esp->issue_SC), this = esp->issue_SC;
		    this;
		    prev = (Scsi_Cmnd **) &(this->host_scribble),
		    this = (Scsi_Cmnd *) this->host_scribble) {
			if(this == SCptr) {
				*prev = (Scsi_Cmnd *) this->host_scribble;
				this->host_scribble = NULL;
				esp_release_dmabufs(esp, this);
				this->result = DID_ABORT << 16;
				this->done(this);
				if(don)
					esp->dma_ints_on(esp);
				return SUCCESS;
			}
		}
	}

	/* Yuck, the command to abort is disconnected, it is not
	 * worth trying to abort it now if something else is live
	 * on the bus at this time.  So, we let the SCSI code wait
	 * a little bit and try again later.
	 */
	if(esp->current_SC) {
		if(don)
			esp->dma_ints_on(esp);
		return FAILED;
	}

	/* It's disconnected, we have to reconnect to re-establish
	 * the nexus and tell the device to abort.  However, we really
	 * cannot 'reconnect' per se.  Don't try to be fancy, just
	 * indicate failure, which causes our caller to reset the whole
	 * bus.
	 */

	if(don)
		esp->dma_ints_on(esp);
	return FAILED;
}

/* We've sent ESP_CMD_RS to the ESP, the interrupt had just
 * arrived indicating the end of the SCSI bus reset.  Our job
 * is to clean out the command queues and begin re-execution
 * of SCSI commands once more.
 */
static int esp_finish_reset(struct NCR_ESP *esp,
			    struct ESP_regs *eregs)
{
	Scsi_Cmnd *sp = esp->current_SC;

	/* Clean up currently executing command, if any. */
	if (sp != NULL) {
		esp_release_dmabufs(esp, sp);
		sp->result = (DID_RESET << 16);
		sp->scsi_done(sp);
		esp->current_SC = NULL;
	}

	/* Clean up disconnected queue, they have been invalidated
	 * by the bus reset.
	 */
	if (esp->disconnected_SC) {
		while((sp = remove_first_SC(&esp->disconnected_SC)) != NULL) {
			esp_release_dmabufs(esp, sp);
			sp->result = (DID_RESET << 16);
			sp->scsi_done(sp);
		}
	}

	/* SCSI bus reset is complete. */
	esp->resetting_bus = 0;
	wake_up(&esp->reset_queue);

	/* Ok, now it is safe to get commands going once more. */
	if(esp->issue_SC)
		esp_exec_cmd(esp);

	return do_intr_end;
}

static int esp_do_resetbus(struct NCR_ESP *esp,
			   struct ESP_regs *eregs)
{
	ESPLOG(("esp%d: Resetting scsi bus\n", esp->esp_id));
	esp->resetting_bus = 1;
	esp_cmd(esp, eregs, ESP_CMD_RS);

	return do_intr_end;
}

/* Reset ESP chip, reset hanging bus, then kill active and
 * disconnected commands for targets without soft reset.
 *
 * The host_lock is acquired by caller.
 */
int esp_reset(Scsi_Cmnd *SCptr)
{
	struct NCR_ESP *esp = (struct NCR_ESP *) SCptr->device->host->hostdata;

	spin_lock_irq(esp->ehost->host_lock);
	(void) esp_do_resetbus(esp, esp->eregs);
	spin_unlock_irq(esp->ehost->host_lock);

	wait_event(esp->reset_queue, (esp->resetting_bus == 0));

	return SUCCESS;
}

/* Internal ESP done function. */
static void esp_done(struct NCR_ESP *esp, int error)
{
	Scsi_Cmnd *done_SC;

	if(esp->current_SC) {
		done_SC = esp->current_SC;
		esp->current_SC = NULL;
		esp_release_dmabufs(esp, done_SC);
		done_SC->result = error;
		done_SC->scsi_done(done_SC);

		/* Bus is free, issue any commands in the queue. */
		if(esp->issue_SC && !esp->current_SC)
			esp_exec_cmd(esp);
	} else {
		/* Panic is safe as current_SC is null so we may still
		 * be able to accept more commands to sync disk buffers.
		 */
		ESPLOG(("panicing\n"));
		panic("esp: done() called with NULL esp->current_SC");
	}
}

/* Wheee, ESP interrupt engine. */  

/* Forward declarations. */
static int esp_do_phase_determine(struct NCR_ESP *esp, 
				  struct ESP_regs *eregs);
static int esp_do_data_finale(struct NCR_ESP *esp, struct ESP_regs *eregs);
static int esp_select_complete(struct NCR_ESP *esp, struct ESP_regs *eregs);
static int esp_do_status(struct NCR_ESP *esp, struct ESP_regs *eregs);
static int esp_do_msgin(struct NCR_ESP *esp, struct ESP_regs *eregs);
static int esp_do_msgindone(struct NCR_ESP *esp, struct ESP_regs *eregs);
static int esp_do_msgout(struct NCR_ESP *esp, struct ESP_regs *eregs);
static int esp_do_cmdbegin(struct NCR_ESP *esp, struct ESP_regs *eregs);

#define sreg_datainp(__sreg)  (((__sreg) & ESP_STAT_PMASK) == ESP_DIP)
#define sreg_dataoutp(__sreg) (((__sreg) & ESP_STAT_PMASK) == ESP_DOP)

/* We try to avoid some interrupts by jumping ahead and see if the ESP
 * has gotten far enough yet.  Hence the following.
 */
static inline int skipahead1(struct NCR_ESP *esp, struct ESP_regs *eregs,
			     Scsi_Cmnd *scp, int prev_phase, int new_phase)
{
	if(scp->SCp.sent_command != prev_phase)
		return 0;

	if(esp->dma_irq_p(esp)) {
		/* Yes, we are able to save an interrupt. */
		esp->sreg = (esp_read(eregs->esp_status) & ~(ESP_STAT_INTR));
		esp->ireg = esp_read(eregs->esp_intrpt);
		if(!(esp->ireg & ESP_INTR_SR))
			return 0;
		else
			return do_reset_complete;
	}
	/* Ho hum, target is taking forever... */
	scp->SCp.sent_command = new_phase; /* so we don't recurse... */
	return do_intr_end;
}

static inline int skipahead2(struct NCR_ESP *esp,
			     struct ESP_regs *eregs,
			     Scsi_Cmnd *scp, int prev_phase1, int prev_phase2,
			     int new_phase)
{
	if(scp->SCp.sent_command != prev_phase1 &&
	   scp->SCp.sent_command != prev_phase2)
		return 0;
	if(esp->dma_irq_p(esp)) {
		/* Yes, we are able to save an interrupt. */
		esp->sreg = (esp_read(eregs->esp_status) & ~(ESP_STAT_INTR));
		esp->ireg = esp_read(eregs->esp_intrpt);
		if(!(esp->ireg & ESP_INTR_SR))
			return 0;
		else
			return do_reset_complete;
	}
	/* Ho hum, target is taking forever... */
	scp->SCp.sent_command = new_phase; /* so we don't recurse... */
	return do_intr_end;
}

/* Misc. esp helper macros. */
#define esp_setcount(__eregs, __cnt) \
	esp_write((__eregs)->esp_tclow, ((__cnt) & 0xff)); \
	esp_write((__eregs)->esp_tcmed, (((__cnt) >> 8) & 0xff))

#define esp_getcount(__eregs) \
	((esp_read((__eregs)->esp_tclow)&0xff) | \
	 ((esp_read((__eregs)->esp_tcmed)&0xff) << 8))

#define fcount(__esp, __eregs) \
	(esp_read((__eregs)->esp_fflags) & ESP_FF_FBYTES)

#define fnzero(__esp, __eregs) \
	(esp_read((__eregs)->esp_fflags) & ESP_FF_ONOTZERO)

/* XXX speculative nops unnecessary when continuing amidst a data phase
 * XXX even on esp100!!!  another case of flooding the bus with I/O reg
 * XXX writes...
 */
#define esp_maybe_nop(__esp, __eregs) \
	if((__esp)->erev == esp100) \
		esp_cmd((__esp), (__eregs), ESP_CMD_NULL)

#define sreg_to_dataphase(__sreg) \
	((((__sreg) & ESP_STAT_PMASK) == ESP_DOP) ? in_dataout : in_datain)

/* The ESP100 when in synchronous data phase, can mistake a long final
 * REQ pulse from the target as an extra byte, it places whatever is on
 * the data lines into the fifo.  For now, we will assume when this
 * happens that the target is a bit quirky and we don't want to
 * be talking synchronously to it anyways.  Regardless, we need to
 * tell the ESP to eat the extraneous byte so that we can proceed
 * to the next phase.
 */
static inline int esp100_sync_hwbug(struct NCR_ESP *esp, struct ESP_regs *eregs,
				    Scsi_Cmnd *sp, int fifocnt)
{
	/* Do not touch this piece of code. */
	if((!(esp->erev == esp100)) ||
	   (!(sreg_datainp((esp->sreg = esp_read(eregs->esp_status))) && !fifocnt) &&
	    !(sreg_dataoutp(esp->sreg) && !fnzero(esp, eregs)))) {
		if(sp->SCp.phase == in_dataout)
			esp_cmd(esp, eregs, ESP_CMD_FLUSH);
		return 0;
	} else {
		/* Async mode for this guy. */
		build_sync_nego_msg(esp, 0, 0);

		/* Ack the bogus byte, but set ATN first. */
		esp_cmd(esp, eregs, ESP_CMD_SATN);
		esp_cmd(esp, eregs, ESP_CMD_MOK);
		return 1;
	}
}

/* This closes the window during a selection with a reselect pending, because
 * we use DMA for the selection process the FIFO should hold the correct
 * contents if we get reselected during this process.  So we just need to
 * ack the possible illegal cmd interrupt pending on the esp100.
 */
static inline int esp100_reconnect_hwbug(struct NCR_ESP *esp,
					 struct ESP_regs *eregs)
{
	volatile unchar junk;

	if(esp->erev != esp100)
		return 0;
	junk = esp_read(eregs->esp_intrpt);

	if(junk & ESP_INTR_SR)
		return 1;
	return 0;
}

/* This verifies the BUSID bits during a reselection so that we know which
 * target is talking to us.
 */
static inline int reconnect_target(struct NCR_ESP *esp, struct ESP_regs *eregs)
{
	int it, me = esp->scsi_id_mask, targ = 0;

	if(2 != fcount(esp, eregs))
		return -1;
	it = esp_read(eregs->esp_fdata);
	if(!(it & me))
		return -1;
	it &= ~me;
	if(it & (it - 1))
		return -1;
	while(!(it & 1))
		targ++, it >>= 1;
	return targ;
}

/* This verifies the identify from the target so that we know which lun is
 * being reconnected.
 */
static inline int reconnect_lun(struct NCR_ESP *esp, struct ESP_regs *eregs)
{
	int lun;

	if((esp->sreg & ESP_STAT_PMASK) != ESP_MIP)
		return -1;
	lun = esp_read(eregs->esp_fdata);

	/* Yes, you read this correctly.  We report lun of zero
	 * if we see parity error.  ESP reports parity error for
	 * the lun byte, and this is the only way to hope to recover
	 * because the target is connected.
	 */
	if(esp->sreg & ESP_STAT_PERR)
		return 0;

	/* Check for illegal bits being set in the lun. */
	if((lun & 0x40) || !(lun & 0x80))
		return -1;

	return lun & 7;
}

/* This puts the driver in a state where it can revitalize a command that
 * is being continued due to reselection.
 */
static inline void esp_connect(struct NCR_ESP *esp, struct ESP_regs *eregs,
			       Scsi_Cmnd *sp)
{
	struct scsi_device *dp = sp->device;
	struct esp_device *esp_dev = dp->hostdata;

	if(esp->prev_soff  != esp_dev->sync_max_offset ||
	   esp->prev_stp   != esp_dev->sync_min_period ||
	   (esp->erev > esp100a &&
	    esp->prev_cfg3 != esp->config3[scmd_id(sp)])) {
		esp->prev_soff = esp_dev->sync_max_offset;
		esp_write(eregs->esp_soff, esp->prev_soff);
		esp->prev_stp = esp_dev->sync_min_period;
		esp_write(eregs->esp_stp, esp->prev_stp);
		if(esp->erev > esp100a) {
			esp->prev_cfg3 = esp->config3[scmd_id(sp)];
			esp_write(eregs->esp_cfg3, esp->prev_cfg3);
		} 
	}
	esp->current_SC = sp;
}

/* This will place the current working command back into the issue queue
 * if we are to receive a reselection amidst a selection attempt.
 */
static inline void esp_reconnect(struct NCR_ESP *esp, Scsi_Cmnd *sp)
{
	if(!esp->disconnected_SC)
		ESPLOG(("esp%d: Weird, being reselected but disconnected "
			"command queue is empty.\n", esp->esp_id));
	esp->snip = 0;
	esp->current_SC = NULL;
	sp->SCp.phase = not_issued;
	append_SC(&esp->issue_SC, sp);
}

/* Begin message in phase. */
static int esp_do_msgin(struct NCR_ESP *esp, struct ESP_regs *eregs)
{
	esp_cmd(esp, eregs, ESP_CMD_FLUSH);
	esp_maybe_nop(esp, eregs);
	esp_cmd(esp, eregs, ESP_CMD_TI);
	esp->msgin_len = 1;
	esp->msgin_ctr = 0;
	esp_advance_phase(esp->current_SC, in_msgindone);
	return do_work_bus;
}

static inline void advance_sg(struct NCR_ESP *esp, Scsi_Cmnd *sp)
{
	++sp->SCp.buffer;
	--sp->SCp.buffers_residual;
	sp->SCp.this_residual = sp->SCp.buffer->length;
	if (esp->dma_advance_sg)
		esp->dma_advance_sg (sp);
	else
		sp->SCp.ptr = (char *) virt_to_phys((page_address(sp->SCp.buffer->page) + sp->SCp.buffer->offset));

}

/* Please note that the way I've coded these routines is that I _always_
 * check for a disconnect during any and all information transfer
 * phases.  The SCSI standard states that the target _can_ cause a BUS
 * FREE condition by dropping all MSG/CD/IO/BSY signals.  Also note
 * that during information transfer phases the target controls every
 * change in phase, the only thing the initiator can do is "ask" for
 * a message out phase by driving ATN true.  The target can, and sometimes
 * will, completely ignore this request so we cannot assume anything when
 * we try to force a message out phase to abort/reset a target.  Most of
 * the time the target will eventually be nice and go to message out, so
 * we may have to hold on to our state about what we want to tell the target
 * for some period of time.
 */

/* I think I have things working here correctly.  Even partial transfers
 * within a buffer or sub-buffer should not upset us at all no matter
 * how bad the target and/or ESP fucks things up.
 */
static int esp_do_data(struct NCR_ESP *esp, struct ESP_regs *eregs)
{
	Scsi_Cmnd *SCptr = esp->current_SC;
	int thisphase, hmuch;

	ESPDATA(("esp_do_data: "));
	esp_maybe_nop(esp, eregs);
	thisphase = sreg_to_dataphase(esp->sreg);
	esp_advance_phase(SCptr, thisphase);
	ESPDATA(("newphase<%s> ", (thisphase == in_datain) ? "DATAIN" : "DATAOUT"));
	hmuch = esp->dma_can_transfer(esp, SCptr);

	/*
	 * XXX MSch: cater for PIO transfer here; PIO used if hmuch == 0
	 */
	if (hmuch) {	/* DMA */
		/*
		 * DMA
		 */
		ESPDATA(("hmuch<%d> ", hmuch));
		esp->current_transfer_size = hmuch;
		esp_setcount(eregs, (esp->fas_premature_intr_workaround ?
				     (hmuch + 0x40) : hmuch));
		esp->dma_setup(esp, (__u32)((unsigned long)SCptr->SCp.ptr), 
			       hmuch, (thisphase == in_datain));
		ESPDATA(("DMA|TI --> do_intr_end\n"));
		esp_cmd(esp, eregs, ESP_CMD_DMA | ESP_CMD_TI);
		return do_intr_end;
		/*
		 * end DMA
		 */
	} else {
		/*
		 * PIO
		 */
		int oldphase, i = 0; /* or where we left off last time ?? esp->current_data ?? */
		int fifocnt = 0;
		unsigned char *p = phys_to_virt((unsigned long)SCptr->SCp.ptr);

		oldphase = esp_read(eregs->esp_status) & ESP_STAT_PMASK;

		/*
		 * polled transfer; ugly, can we make this happen in a DRQ 
		 * interrupt handler ??
		 * requires keeping track of state information in host or 
		 * command struct!
		 * Problem: I've never seen a DRQ happen on Mac, not even
		 * with ESP_CMD_DMA ...
		 */

		/* figure out how much needs to be transferred */
		hmuch = SCptr->SCp.this_residual;
		ESPDATA(("hmuch<%d> pio ", hmuch));
		esp->current_transfer_size = hmuch;

		/* tell the ESP ... */
		esp_setcount(eregs, hmuch);

		/* loop */
		while (hmuch) {
			int j, fifo_stuck = 0, newphase;
			unsigned long timeout;
#if 0
			unsigned long flags;
#endif
#if 0
			if ( i % 10 )
				ESPDATA(("\r"));
			else
				ESPDATA(( /*"\n"*/ "\r"));
#endif
#if 0
			local_irq_save(flags);
#endif
			if(thisphase == in_datain) {
				/* 'go' ... */ 
				esp_cmd(esp, eregs, ESP_CMD_TI);

				/* wait for data */
				timeout = 1000000;
				while (!((esp->sreg=esp_read(eregs->esp_status)) & ESP_STAT_INTR) && --timeout)
					udelay(2);
				if (timeout == 0)
					printk("DRQ datain timeout! \n");

				newphase = esp->sreg & ESP_STAT_PMASK;

				/* see how much we got ... */
				fifocnt = (esp_read(eregs->esp_fflags) & ESP_FF_FBYTES);

				if (!fifocnt)
					fifo_stuck++;
				else
					fifo_stuck = 0;

				ESPDATA(("\rgot %d st %x ph %x", fifocnt, esp->sreg, newphase));

				/* read fifo */
				for(j=0;j<fifocnt;j++)
					p[i++] = esp_read(eregs->esp_fdata);

				ESPDATA(("(%d) ", i));

				/* how many to go ?? */
				hmuch -= fifocnt;

				/* break if status phase !! */
				if(newphase == ESP_STATP) {
					/* clear int. */
					esp->ireg = esp_read(eregs->esp_intrpt);
					break;
				}
			} else {
#define MAX_FIFO 8
				/* how much will fit ? */
				int this_count = MAX_FIFO - fifocnt;
				if (this_count > hmuch)
					this_count = hmuch;

				/* fill fifo */
				for(j=0;j<this_count;j++)
					esp_write(eregs->esp_fdata, p[i++]);

				/* how many left if this goes out ?? */
				hmuch -= this_count;

				/* 'go' ... */ 
				esp_cmd(esp, eregs, ESP_CMD_TI);

				/* wait for 'got it' */
				timeout = 1000000;
				while (!((esp->sreg=esp_read(eregs->esp_status)) & ESP_STAT_INTR) && --timeout)
					udelay(2);
				if (timeout == 0)
					printk("DRQ dataout timeout!  \n");

				newphase = esp->sreg & ESP_STAT_PMASK;

				/* need to check how much was sent ?? */
				fifocnt = (esp_read(eregs->esp_fflags) & ESP_FF_FBYTES);

				ESPDATA(("\rsent %d st %x ph %x", this_count - fifocnt, esp->sreg, newphase));

				ESPDATA(("(%d) ", i));

				/* break if status phase !! */
				if(newphase == ESP_STATP) {
					/* clear int. */
					esp->ireg = esp_read(eregs->esp_intrpt);
					break;
				}

			}

			/* clear int. */
			esp->ireg = esp_read(eregs->esp_intrpt);

			ESPDATA(("ir %x ... ", esp->ireg));

			if (hmuch == 0)
				ESPDATA(("done! \n"));

#if 0
			local_irq_restore(flags);
#endif

			/* check new bus phase */
			if (newphase != oldphase && i < esp->current_transfer_size) {
				/* something happened; disconnect ?? */
				ESPDATA(("phase change, dropped out with %d done ... ", i));
				break;
			}

			/* check int. status */
			if (esp->ireg & ESP_INTR_DC) {
				/* disconnect */
				ESPDATA(("disconnect; %d transferred ... ", i));
				break;
			} else if (esp->ireg & ESP_INTR_FDONE) {
				/* function done */
				ESPDATA(("function done; %d transferred ... ", i));
				break;
			}

			/* XXX fixme: bail out on stall */
			if (fifo_stuck > 10) {
				/* we're stuck */
				ESPDATA(("fifo stall; %d transferred ... ", i));
				break;
			}
		}

		ESPDATA(("\n"));
		/* check successful completion ?? */

		if (thisphase == in_dataout)
			hmuch += fifocnt; /* stuck?? adjust data pointer ...*/

		/* tell do_data_finale how much was transferred */
		esp->current_transfer_size -= hmuch;

		/* still not completely sure on this one ... */		
		return /*do_intr_end*/ do_work_bus /*do_phase_determine*/ ;

		/*
		 * end PIO
		 */
	}
	return do_intr_end;
}

/* See how successful the data transfer was. */
static int esp_do_data_finale(struct NCR_ESP *esp,
			      struct ESP_regs *eregs)
{
	Scsi_Cmnd *SCptr = esp->current_SC;
	struct esp_device *esp_dev = SCptr->device->hostdata;
	int bogus_data = 0, bytes_sent = 0, fifocnt, ecount = 0;

	if(esp->dma_led_off)
		esp->dma_led_off(esp);

	ESPDATA(("esp_do_data_finale: "));

	if(SCptr->SCp.phase == in_datain) {
		if(esp->sreg & ESP_STAT_PERR) {
			/* Yuck, parity error.  The ESP asserts ATN
			 * so that we can go to message out phase
			 * immediately and inform the target that
			 * something bad happened.
			 */
			ESPLOG(("esp%d: data bad parity detected.\n",
				esp->esp_id));
			esp->cur_msgout[0] = INITIATOR_ERROR;
			esp->msgout_len = 1;
		}
		if(esp->dma_drain)
			esp->dma_drain(esp);
	}
	if(esp->dma_invalidate)
		esp->dma_invalidate(esp);

	/* This could happen for the above parity error case. */
	if(!(esp->ireg == ESP_INTR_BSERV)) {
		/* Please go to msgout phase, please please please... */
		ESPLOG(("esp%d: !BSERV after data, probably to msgout\n",
			esp->esp_id));
		return esp_do_phase_determine(esp, eregs);
	}	

	/* Check for partial transfers and other horrible events. */
	fifocnt = (esp_read(eregs->esp_fflags) & ESP_FF_FBYTES);
	ecount = esp_getcount(eregs);
	if(esp->fas_premature_intr_workaround)
		ecount -= 0x40;
	bytes_sent = esp->current_transfer_size;

	ESPDATA(("trans_sz=%d, ", bytes_sent));
	if(!(esp->sreg & ESP_STAT_TCNT))
		bytes_sent -= ecount;
	if(SCptr->SCp.phase == in_dataout)
		bytes_sent -= fifocnt;

	ESPDATA(("bytes_sent=%d (ecount=%d, fifocnt=%d), ", bytes_sent,
		 ecount, fifocnt));

	/* If we were in synchronous mode, check for peculiarities. */
	if(esp_dev->sync_max_offset)
		bogus_data = esp100_sync_hwbug(esp, eregs, SCptr, fifocnt);
	else
		esp_cmd(esp, eregs, ESP_CMD_FLUSH);

	/* Until we are sure of what has happened, we are certainly
	 * in the dark.
	 */
	esp_advance_phase(SCptr, in_the_dark);

	/* Check for premature interrupt condition. Can happen on FAS2x6
	 * chips. QLogic recommends a workaround by overprogramming the
	 * transfer counters, but this makes doing scatter-gather impossible.
	 * Until there is a way to disable scatter-gather for a single target,
	 * and not only for the entire host adapter as it is now, the workaround
	 * is way to expensive performance wise.
	 * Instead, it turns out that when this happens the target has disconnected
	 * already but it doesn't show in the interrupt register. Compensate for
	 * that here to try and avoid a SCSI bus reset.
	 */
	if(!esp->fas_premature_intr_workaround && (fifocnt == 1) &&
	   sreg_dataoutp(esp->sreg)) {
		ESPLOG(("esp%d: Premature interrupt, enabling workaround\n",
			esp->esp_id));
#if 0
		/* Disable scatter-gather operations, they are not possible
		 * when using this workaround.
		 */
		esp->ehost->sg_tablesize = 0;
		esp->ehost->use_clustering = ENABLE_CLUSTERING;
		esp->fas_premature_intr_workaround = 1;
		bytes_sent = 0;
		if(SCptr->use_sg) {
			ESPLOG(("esp%d: Aborting scatter-gather operation\n",
				esp->esp_id));
			esp->cur_msgout[0] = ABORT;
			esp->msgout_len = 1;
			esp->msgout_ctr = 0;
			esp_cmd(esp, eregs, ESP_CMD_SATN);
			esp_setcount(eregs, 0xffff);
			esp_cmd(esp, eregs, ESP_CMD_NULL);
			esp_cmd(esp, eregs, ESP_CMD_TPAD | ESP_CMD_DMA);
			return do_intr_end;
		}
#else
		/* Just set the disconnected bit. That's what appears to
		 * happen anyway. The state machine will pick it up when
		 * we return.
		 */
		esp->ireg |= ESP_INTR_DC;
#endif
        }

	if(bytes_sent < 0) {
		/* I've seen this happen due to lost state in this
		 * driver.  No idea why it happened, but allowing
		 * this value to be negative caused things to
		 * lock up.  This allows greater chance of recovery.
		 * In fact every time I've seen this, it has been
		 * a driver bug without question.
		 */
		ESPLOG(("esp%d: yieee, bytes_sent < 0!\n", esp->esp_id));
		ESPLOG(("esp%d: csz=%d fifocount=%d ecount=%d\n",
			esp->esp_id,
			esp->current_transfer_size, fifocnt, ecount));
		ESPLOG(("esp%d: use_sg=%d ptr=%p this_residual=%d\n",
			esp->esp_id,
			SCptr->use_sg, SCptr->SCp.ptr, SCptr->SCp.this_residual));
		ESPLOG(("esp%d: Forcing async for target %d\n", esp->esp_id, 
			SCptr->device->id));
		SCptr->device->borken = 1;
		esp_dev->sync = 0;
		bytes_sent = 0;
	}

	/* Update the state of our transfer. */
	SCptr->SCp.ptr += bytes_sent;
	SCptr->SCp.this_residual -= bytes_sent;
	if(SCptr->SCp.this_residual < 0) {
		/* shit */
		ESPLOG(("esp%d: Data transfer overrun.\n", esp->esp_id));
		SCptr->SCp.this_residual = 0;
	}

	/* Maybe continue. */
	if(!bogus_data) {
		ESPDATA(("!bogus_data, "));
		/* NO MATTER WHAT, we advance the scatterlist,
		 * if the target should decide to disconnect
		 * in between scatter chunks (which is common)
		 * we could die horribly!  I used to have the sg
		 * advance occur only if we are going back into
		 * (or are staying in) a data phase, you can
		 * imagine the hell I went through trying to
		 * figure this out.
		 */
		if(!SCptr->SCp.this_residual && SCptr->SCp.buffers_residual)
			advance_sg(esp, SCptr);
#ifdef DEBUG_ESP_DATA
		if(sreg_datainp(esp->sreg) || sreg_dataoutp(esp->sreg)) {
			ESPDATA(("to more data\n"));
		} else {
			ESPDATA(("to new phase\n"));
		}
#endif
		return esp_do_phase_determine(esp, eregs);
	}
	/* Bogus data, just wait for next interrupt. */
	ESPLOG(("esp%d: bogus_data during end of data phase\n",
		esp->esp_id));
	return do_intr_end;
}

/* We received a non-good status return at the end of
 * running a SCSI command.  This is used to decide if
 * we should clear our synchronous transfer state for
 * such a device when that happens.
 *
 * The idea is that when spinning up a disk or rewinding
 * a tape, we don't want to go into a loop re-negotiating
 * synchronous capabilities over and over.
 */
static int esp_should_clear_sync(Scsi_Cmnd *sp)
{
	unchar cmd1 = sp->cmnd[0];
	unchar cmd2 = sp->data_cmnd[0];

	/* These cases are for spinning up a disk and
	 * waiting for that spinup to complete.
	 */
	if(cmd1 == START_STOP ||
	   cmd2 == START_STOP)
		return 0;

	if(cmd1 == TEST_UNIT_READY ||
	   cmd2 == TEST_UNIT_READY)
		return 0;

	/* One more special case for SCSI tape drives,
	 * this is what is used to probe the device for
	 * completion of a rewind or tape load operation.
	 */
	if(sp->device->type == TYPE_TAPE) {
		if(cmd1 == MODE_SENSE ||
		   cmd2 == MODE_SENSE)
			return 0;
	}

	return 1;
}

/* Either a command is completing or a target is dropping off the bus
 * to continue the command in the background so we can do other work.
 */
static int esp_do_freebus(struct NCR_ESP *esp, struct ESP_regs *eregs)
{
	Scsi_Cmnd *SCptr = esp->current_SC;
	int rval;

	rval = skipahead2(esp, eregs, SCptr, in_status, in_msgindone, in_freeing);
	if(rval)
		return rval;

	if(esp->ireg != ESP_INTR_DC) {
		ESPLOG(("esp%d: Target will not disconnect\n", esp->esp_id));
		return do_reset_bus; /* target will not drop BSY... */
	}
	esp->msgout_len = 0;
	esp->prevmsgout = NOP;
	if(esp->prevmsgin == COMMAND_COMPLETE) {
		struct esp_device *esp_dev = SCptr->device->hostdata;
		/* Normal end of nexus. */
		if(esp->disconnected_SC)
			esp_cmd(esp, eregs, ESP_CMD_ESEL);

		if(SCptr->SCp.Status != GOOD &&
		   SCptr->SCp.Status != CONDITION_GOOD &&
		   ((1<<scmd_id(SCptr)) & esp->targets_present) &&
		   esp_dev->sync && esp_dev->sync_max_offset) {
			/* SCSI standard says that the synchronous capabilities
			 * should be renegotiated at this point.  Most likely
			 * we are about to request sense from this target
			 * in which case we want to avoid using sync
			 * transfers until we are sure of the current target
			 * state.
			 */
			ESPMISC(("esp: Status <%d> for target %d lun %d\n",
				 SCptr->SCp.Status, SCptr->device->id, SCptr->device->lun));

			/* But don't do this when spinning up a disk at
			 * boot time while we poll for completion as it
			 * fills up the console with messages.  Also, tapes
			 * can report not ready many times right after
			 * loading up a tape.
			 */
			if(esp_should_clear_sync(SCptr) != 0)
				esp_dev->sync = 0;
		}
		ESPDISC(("F<%02x,%02x>", SCptr->device->id, SCptr->device->lun));
		esp_done(esp, ((SCptr->SCp.Status & 0xff) |
			       ((SCptr->SCp.Message & 0xff)<<8) |
			       (DID_OK << 16)));
	} else if(esp->prevmsgin == DISCONNECT) {
		/* Normal disconnect. */
		esp_cmd(esp, eregs, ESP_CMD_ESEL);
		ESPDISC(("D<%02x,%02x>", SCptr->device->id, SCptr->device->lun));
		append_SC(&esp->disconnected_SC, SCptr);
		esp->current_SC = NULL;
		if(esp->issue_SC)
			esp_exec_cmd(esp);
	} else {
		/* Driver bug, we do not expect a disconnect here
		 * and should not have advanced the state engine
		 * to in_freeing.
		 */
		ESPLOG(("esp%d: last msg not disc and not cmd cmplt.\n",
			esp->esp_id));
		return do_reset_bus;
	}
	return do_intr_end;
}

/* When a reselect occurs, and we cannot find the command to
 * reconnect to in our queues, we do this.
 */
static int esp_bad_reconnect(struct NCR_ESP *esp)
{
	Scsi_Cmnd *sp;

	ESPLOG(("esp%d: Eieeee, reconnecting unknown command!\n",
		esp->esp_id));
	ESPLOG(("QUEUE DUMP\n"));
	sp = esp->issue_SC;
	ESPLOG(("esp%d: issue_SC[", esp->esp_id));
	while(sp) {
		ESPLOG(("<%02x,%02x>", sp->device->id, sp->device->lun));
		sp = (Scsi_Cmnd *) sp->host_scribble;
	}
	ESPLOG(("]\n"));
	sp = esp->current_SC;
	ESPLOG(("esp%d: current_SC[", esp->esp_id));
	while(sp) {
		ESPLOG(("<%02x,%02x>", sp->device->id, sp->device->lun));
		sp = (Scsi_Cmnd *) sp->host_scribble;
	}
	ESPLOG(("]\n"));
	sp = esp->disconnected_SC;
	ESPLOG(("esp%d: disconnected_SC[", esp->esp_id));
	while(sp) {
		ESPLOG(("<%02x,%02x>", sp->device->id, sp->device->lun));
		sp = (Scsi_Cmnd *) sp->host_scribble;
	}
	ESPLOG(("]\n"));
	return do_reset_bus;
}

/* Do the needy when a target tries to reconnect to us. */
static int esp_do_reconnect(struct NCR_ESP *esp, 
			    struct ESP_regs *eregs)
{
	int lun, target;
	Scsi_Cmnd *SCptr;

	/* Check for all bogus conditions first. */
	target = reconnect_target(esp, eregs);
	if(target < 0) {
		ESPDISC(("bad bus bits\n"));
		return do_reset_bus;
	}
	lun = reconnect_lun(esp, eregs);
	if(lun < 0) {
		ESPDISC(("target=%2x, bad identify msg\n", target));
		return do_reset_bus;
	}

	/* Things look ok... */
	ESPDISC(("R<%02x,%02x>", target, lun));

	esp_cmd(esp, eregs, ESP_CMD_FLUSH);
	if(esp100_reconnect_hwbug(esp, eregs))
		return do_reset_bus;
	esp_cmd(esp, eregs, ESP_CMD_NULL);

	SCptr = remove_SC(&esp->disconnected_SC, (unchar) target, (unchar) lun);
	if(!SCptr)
		return esp_bad_reconnect(esp);

	esp_connect(esp, eregs, SCptr);
	esp_cmd(esp, eregs, ESP_CMD_MOK);

	/* Reconnect implies a restore pointers operation. */
	esp_restore_pointers(esp, SCptr);

	esp->snip = 0;
	esp_advance_phase(SCptr, in_the_dark);
	return do_intr_end;
}

/* End of NEXUS (hopefully), pick up status + message byte then leave if
 * all goes well.
 */
static int esp_do_status(struct NCR_ESP *esp, struct ESP_regs *eregs)
{
	Scsi_Cmnd *SCptr = esp->current_SC;
	int intr, rval;

	rval = skipahead1(esp, eregs, SCptr, in_the_dark, in_status);
	if(rval)
		return rval;

	intr = esp->ireg;
	ESPSTAT(("esp_do_status: "));
	if(intr != ESP_INTR_DC) {
		int message_out = 0; /* for parity problems */

		/* Ack the message. */
		ESPSTAT(("ack msg, "));
		esp_cmd(esp, eregs, ESP_CMD_MOK);

		if(esp->dma_poll)
			esp->dma_poll(esp, (unsigned char *) esp->esp_command);

		ESPSTAT(("got something, "));
		/* ESP chimes in with one of
		 *
		 * 1) function done interrupt:
		 *	both status and message in bytes
		 *	are available
		 *
		 * 2) bus service interrupt:
		 *	only status byte was acquired
		 *
		 * 3) Anything else:
		 *	can't happen, but we test for it
		 *	anyways
		 *
		 * ALSO: If bad parity was detected on either
		 *       the status _or_ the message byte then
		 *       the ESP has asserted ATN on the bus
		 *       and we must therefore wait for the
		 *       next phase change.
		 */
		if(intr & ESP_INTR_FDONE) {
			/* We got it all, hallejulia. */
			ESPSTAT(("got both, "));
			SCptr->SCp.Status = esp->esp_command[0];
			SCptr->SCp.Message = esp->esp_command[1];
			esp->prevmsgin = SCptr->SCp.Message;
			esp->cur_msgin[0] = SCptr->SCp.Message;
			if(esp->sreg & ESP_STAT_PERR) {
				/* There was bad parity for the
				 * message byte, the status byte
				 * was ok.
				 */
				message_out = MSG_PARITY_ERROR;
			}
		} else if(intr == ESP_INTR_BSERV) {
			/* Only got status byte. */
			ESPLOG(("esp%d: got status only, ", esp->esp_id));
			if(!(esp->sreg & ESP_STAT_PERR)) {
				SCptr->SCp.Status = esp->esp_command[0];
				SCptr->SCp.Message = 0xff;
			} else {
				/* The status byte had bad parity.
				 * we leave the scsi_pointer Status
				 * field alone as we set it to a default
				 * of CHECK_CONDITION in esp_queue.
				 */
				message_out = INITIATOR_ERROR;
			}
		} else {
			/* This shouldn't happen ever. */
			ESPSTAT(("got bolixed\n"));
			esp_advance_phase(SCptr, in_the_dark);
			return esp_do_phase_determine(esp, eregs);
		}

		if(!message_out) {
			ESPSTAT(("status=%2x msg=%2x, ", SCptr->SCp.Status,
				SCptr->SCp.Message));
			if(SCptr->SCp.Message == COMMAND_COMPLETE) {
				ESPSTAT(("and was COMMAND_COMPLETE\n"));
				esp_advance_phase(SCptr, in_freeing);
				return esp_do_freebus(esp, eregs);
			} else {
				ESPLOG(("esp%d: and _not_ COMMAND_COMPLETE\n",
					esp->esp_id));
				esp->msgin_len = esp->msgin_ctr = 1;
				esp_advance_phase(SCptr, in_msgindone);
				return esp_do_msgindone(esp, eregs);
			}
		} else {
			/* With luck we'll be able to let the target
			 * know that bad parity happened, it will know
			 * which byte caused the problems and send it
			 * again.  For the case where the status byte
			 * receives bad parity, I do not believe most
			 * targets recover very well.  We'll see.
			 */
			ESPLOG(("esp%d: bad parity somewhere mout=%2x\n",
				esp->esp_id, message_out));
			esp->cur_msgout[0] = message_out;
			esp->msgout_len = esp->msgout_ctr = 1;
			esp_advance_phase(SCptr, in_the_dark);
			return esp_do_phase_determine(esp, eregs);
		}
	} else {
		/* If we disconnect now, all hell breaks loose. */
		ESPLOG(("esp%d: whoops, disconnect\n", esp->esp_id));
		esp_advance_phase(SCptr, in_the_dark);
		return esp_do_phase_determine(esp, eregs);
	}
}

static int esp_enter_status(struct NCR_ESP *esp,
			    struct ESP_regs *eregs)
{
	unchar thecmd = ESP_CMD_ICCSEQ;

	esp_cmd(esp, eregs, ESP_CMD_FLUSH);

	if(esp->do_pio_cmds) {
		esp_advance_phase(esp->current_SC, in_status);
		esp_cmd(esp, eregs, thecmd);
		while(!(esp_read(esp->eregs->esp_status) & ESP_STAT_INTR));
		esp->esp_command[0] = esp_read(eregs->esp_fdata);
                while(!(esp_read(esp->eregs->esp_status) & ESP_STAT_INTR));
                esp->esp_command[1] = esp_read(eregs->esp_fdata);
	} else {
		esp->esp_command[0] = esp->esp_command[1] = 0xff;
		esp_write(eregs->esp_tclow, 2);
		esp_write(eregs->esp_tcmed, 0);
		esp->dma_init_read(esp, esp->esp_command_dvma, 2);
		thecmd |= ESP_CMD_DMA;
		esp_cmd(esp, eregs, thecmd);
		esp_advance_phase(esp->current_SC, in_status);
	}

	return esp_do_status(esp, eregs);
}

static int esp_disconnect_amidst_phases(struct NCR_ESP *esp,
					struct ESP_regs *eregs)
{
	Scsi_Cmnd *sp = esp->current_SC;
	struct esp_device *esp_dev = sp->device->hostdata;

	/* This means real problems if we see this
	 * here.  Unless we were actually trying
	 * to force the device to abort/reset.
	 */
	ESPLOG(("esp%d: Disconnect amidst phases, ", esp->esp_id));
	ESPLOG(("pphase<%s> cphase<%s>, ",
		phase_string(sp->SCp.phase),
		phase_string(sp->SCp.sent_command)));

	if(esp->disconnected_SC)
		esp_cmd(esp, eregs, ESP_CMD_ESEL);

	switch(esp->cur_msgout[0]) {
	default:
		/* We didn't expect this to happen at all. */
		ESPLOG(("device is bolixed\n"));
		esp_advance_phase(sp, in_tgterror);
		esp_done(esp, (DID_ERROR << 16));
		break;

	case BUS_DEVICE_RESET:
		ESPLOG(("device reset successful\n"));
		esp_dev->sync_max_offset = 0;
		esp_dev->sync_min_period = 0;
		esp_dev->sync = 0;
		esp_advance_phase(sp, in_resetdev);
		esp_done(esp, (DID_RESET << 16));
		break;

	case ABORT:
		ESPLOG(("device abort successful\n"));
		esp_advance_phase(sp, in_abortone);
		esp_done(esp, (DID_ABORT << 16));
		break;

	};
	return do_intr_end;
}

static int esp_enter_msgout(struct NCR_ESP *esp,
			    struct ESP_regs *eregs)
{
	esp_advance_phase(esp->current_SC, in_msgout);
	return esp_do_msgout(esp, eregs);
}

static int esp_enter_msgin(struct NCR_ESP *esp,
			   struct ESP_regs *eregs)
{
	esp_advance_phase(esp->current_SC, in_msgin);
	return esp_do_msgin(esp, eregs);
}

static int esp_enter_cmd(struct NCR_ESP *esp,
			 struct ESP_regs *eregs)
{
	esp_advance_phase(esp->current_SC, in_cmdbegin);
	return esp_do_cmdbegin(esp, eregs);
}

static int esp_enter_badphase(struct NCR_ESP *esp,
			      struct ESP_regs *eregs)
{
	ESPLOG(("esp%d: Bizarre bus phase %2x.\n", esp->esp_id,
		esp->sreg & ESP_STAT_PMASK));
	return do_reset_bus;
}

typedef int (*espfunc_t)(struct NCR_ESP *,
			 struct ESP_regs *);

static espfunc_t phase_vector[] = {
	esp_do_data,		/* ESP_DOP */
	esp_do_data,		/* ESP_DIP */
	esp_enter_cmd,		/* ESP_CMDP */
	esp_enter_status,	/* ESP_STATP */
	esp_enter_badphase,	/* ESP_STAT_PMSG */
	esp_enter_badphase,	/* ESP_STAT_PMSG | ESP_STAT_PIO */
	esp_enter_msgout,	/* ESP_MOP */
	esp_enter_msgin,	/* ESP_MIP */
};

/* The target has control of the bus and we have to see where it has
 * taken us.
 */
static int esp_do_phase_determine(struct NCR_ESP *esp,
				  struct ESP_regs *eregs)
{
	if ((esp->ireg & ESP_INTR_DC) != 0)
		return esp_disconnect_amidst_phases(esp, eregs);
	return phase_vector[esp->sreg & ESP_STAT_PMASK](esp, eregs);
}

/* First interrupt after exec'ing a cmd comes here. */
static int esp_select_complete(struct NCR_ESP *esp, struct ESP_regs *eregs)
{
	Scsi_Cmnd *SCptr = esp->current_SC;
	struct esp_device *esp_dev = SCptr->device->hostdata;
	int cmd_bytes_sent, fcnt;

	fcnt = (esp_read(eregs->esp_fflags) & ESP_FF_FBYTES);
	cmd_bytes_sent = esp->dma_bytes_sent(esp, fcnt);
	if(esp->dma_invalidate)
		esp->dma_invalidate(esp);

	/* Let's check to see if a reselect happened
	 * while we we're trying to select.  This must
	 * be checked first.
	 */
	if(esp->ireg == (ESP_INTR_RSEL | ESP_INTR_FDONE)) {
		esp_reconnect(esp, SCptr);
		return esp_do_reconnect(esp, eregs);
	}

	/* Looks like things worked, we should see a bus service &
	 * a function complete interrupt at this point.  Note we
	 * are doing a direct comparison because we don't want to
	 * be fooled into thinking selection was successful if
	 * ESP_INTR_DC is set, see below.
	 */
	if(esp->ireg == (ESP_INTR_FDONE | ESP_INTR_BSERV)) {
		/* target speaks... */
		esp->targets_present |= (1<<scmd_id(SCptr));

		/* What if the target ignores the sdtr? */
		if(esp->snip)
			esp_dev->sync = 1;

		/* See how far, if at all, we got in getting
		 * the information out to the target.
		 */
		switch(esp->seqreg) {
		default:

		case ESP_STEP_ASEL:
			/* Arbitration won, target selected, but
			 * we are in some phase which is not command
			 * phase nor is it message out phase.
			 *
			 * XXX We've confused the target, obviously.
			 * XXX So clear it's state, but we also end
			 * XXX up clearing everyone elses.  That isn't
			 * XXX so nice.  I'd like to just reset this
			 * XXX target, but if I cannot even get it's
			 * XXX attention and finish selection to talk
			 * XXX to it, there is not much more I can do.
			 * XXX If we have a loaded bus we're going to
			 * XXX spend the next second or so renegotiating
			 * XXX for synchronous transfers.
			 */
			ESPLOG(("esp%d: STEP_ASEL for tgt %d\n",
				esp->esp_id, SCptr->device->id));

		case ESP_STEP_SID:
			/* Arbitration won, target selected, went
			 * to message out phase, sent one message
			 * byte, then we stopped.  ATN is asserted
			 * on the SCSI bus and the target is still
			 * there hanging on.  This is a legal
			 * sequence step if we gave the ESP a select
			 * and stop command.
			 *
			 * XXX See above, I could set the borken flag
			 * XXX in the device struct and retry the
			 * XXX command.  But would that help for
			 * XXX tagged capable targets?
			 */

		case ESP_STEP_NCMD:
			/* Arbitration won, target selected, maybe
			 * sent the one message byte in message out
			 * phase, but we did not go to command phase
			 * in the end.  Actually, we could have sent
			 * only some of the message bytes if we tried
			 * to send out the entire identify and tag
			 * message using ESP_CMD_SA3.
			 */
			cmd_bytes_sent = 0;
			break;

		case ESP_STEP_PPC:
			/* No, not the powerPC pinhead.  Arbitration
			 * won, all message bytes sent if we went to
			 * message out phase, went to command phase
			 * but only part of the command was sent.
			 *
			 * XXX I've seen this, but usually in conjunction
			 * XXX with a gross error which appears to have
			 * XXX occurred between the time I told the
			 * XXX ESP to arbitrate and when I got the
			 * XXX interrupt.  Could I have misloaded the
			 * XXX command bytes into the fifo?  Actually,
			 * XXX I most likely missed a phase, and therefore
			 * XXX went into never never land and didn't even
			 * XXX know it.  That was the old driver though.
			 * XXX What is even more peculiar is that the ESP
			 * XXX showed the proper function complete and
			 * XXX bus service bits in the interrupt register.
			 */

		case ESP_STEP_FINI4:
		case ESP_STEP_FINI5:
		case ESP_STEP_FINI6:
		case ESP_STEP_FINI7:
			/* Account for the identify message */
			if(SCptr->SCp.phase == in_slct_norm)
				cmd_bytes_sent -= 1;
		};
		esp_cmd(esp, eregs, ESP_CMD_NULL);

		/* Be careful, we could really get fucked during synchronous
		 * data transfers if we try to flush the fifo now.
		 */
		if(!fcnt && /* Fifo is empty and... */
		   /* either we are not doing synchronous transfers or... */
		   (!esp_dev->sync_max_offset ||
		    /* We are not going into data in phase. */
		    ((esp->sreg & ESP_STAT_PMASK) != ESP_DIP)))
			esp_cmd(esp, eregs, ESP_CMD_FLUSH); /* flush is safe */

		/* See how far we got if this is not a slow command. */
		if(!esp->esp_slowcmd) {
			if(cmd_bytes_sent < 0)
				cmd_bytes_sent = 0;
			if(cmd_bytes_sent != SCptr->cmd_len) {
				/* Crapola, mark it as a slowcmd
				 * so that we have some chance of
				 * keeping the command alive with
				 * good luck.
				 *
				 * XXX Actually, if we didn't send it all
				 * XXX this means either we didn't set things
				 * XXX up properly (driver bug) or the target
				 * XXX or the ESP detected parity on one of
				 * XXX the command bytes.  This makes much
				 * XXX more sense, and therefore this code
				 * XXX should be changed to send out a
				 * XXX parity error message or if the status
				 * XXX register shows no parity error then
				 * XXX just expect the target to bring the
				 * XXX bus into message in phase so that it
				 * XXX can send us the parity error message.
				 * XXX SCSI sucks...
				 */
				esp->esp_slowcmd = 1;
				esp->esp_scmdp = &(SCptr->cmnd[cmd_bytes_sent]);
				esp->esp_scmdleft = (SCptr->cmd_len - cmd_bytes_sent);
			}
		}

		/* Now figure out where we went. */
		esp_advance_phase(SCptr, in_the_dark);
		return esp_do_phase_determine(esp, eregs);
	}

	/* Did the target even make it? */
	if(esp->ireg == ESP_INTR_DC) {
		/* wheee... nobody there or they didn't like
		 * what we told it to do, clean up.
		 */

		/* If anyone is off the bus, but working on
		 * a command in the background for us, tell
		 * the ESP to listen for them.
		 */
		if(esp->disconnected_SC)
			esp_cmd(esp, eregs, ESP_CMD_ESEL);

		if(((1<<SCptr->device->id) & esp->targets_present) &&
		   esp->seqreg && esp->cur_msgout[0] == EXTENDED_MESSAGE &&
		   (SCptr->SCp.phase == in_slct_msg ||
		    SCptr->SCp.phase == in_slct_stop)) {
			/* shit */
			esp->snip = 0;
			ESPLOG(("esp%d: Failed synchronous negotiation for target %d "
				"lun %d\n", esp->esp_id, SCptr->device->id, SCptr->device->lun));
			esp_dev->sync_max_offset = 0;
			esp_dev->sync_min_period = 0;
			esp_dev->sync = 1; /* so we don't negotiate again */

			/* Run the command again, this time though we
			 * won't try to negotiate for synchronous transfers.
			 *
			 * XXX I'd like to do something like send an
			 * XXX INITIATOR_ERROR or ABORT message to the
			 * XXX target to tell it, "Sorry I confused you,
			 * XXX please come back and I will be nicer next
			 * XXX time".  But that requires having the target
			 * XXX on the bus, and it has dropped BSY on us.
			 */
			esp->current_SC = NULL;
			esp_advance_phase(SCptr, not_issued);
			prepend_SC(&esp->issue_SC, SCptr);
			esp_exec_cmd(esp);
			return do_intr_end;
		}

		/* Ok, this is normal, this is what we see during boot
		 * or whenever when we are scanning the bus for targets.
		 * But first make sure that is really what is happening.
		 */
		if(((1<<SCptr->device->id) & esp->targets_present)) {
			ESPLOG(("esp%d: Warning, live target %d not responding to "
				"selection.\n", esp->esp_id, SCptr->device->id));

			/* This _CAN_ happen.  The SCSI standard states that
			 * the target is to _not_ respond to selection if
			 * _it_ detects bad parity on the bus for any reason.
			 * Therefore, we assume that if we've talked successfully
			 * to this target before, bad parity is the problem.
			 */
			esp_done(esp, (DID_PARITY << 16));
		} else {
			/* Else, there really isn't anyone there. */
			ESPMISC(("esp: selection failure, maybe nobody there?\n"));
			ESPMISC(("esp: target %d lun %d\n",
				 SCptr->device->id, SCptr->device->lun));
			esp_done(esp, (DID_BAD_TARGET << 16));
		}
		return do_intr_end;
	}


	ESPLOG(("esp%d: Selection failure.\n", esp->esp_id));
	printk("esp%d: Currently -- ", esp->esp_id);
	esp_print_ireg(esp->ireg);
	printk(" ");
	esp_print_statreg(esp->sreg);
	printk(" ");
	esp_print_seqreg(esp->seqreg);
	printk("\n");
	printk("esp%d: New -- ", esp->esp_id);
	esp->sreg = esp_read(eregs->esp_status);
	esp->seqreg = esp_read(eregs->esp_sstep);
	esp->ireg = esp_read(eregs->esp_intrpt);
	esp_print_ireg(esp->ireg);
	printk(" ");
	esp_print_statreg(esp->sreg);
	printk(" ");
	esp_print_seqreg(esp->seqreg);
	printk("\n");
	ESPLOG(("esp%d: resetting bus\n", esp->esp_id));
	return do_reset_bus; /* ugh... */
}

/* Continue reading bytes for msgin phase. */
static int esp_do_msgincont(struct NCR_ESP *esp, struct ESP_regs *eregs)
{
	if(esp->ireg & ESP_INTR_BSERV) {
		/* in the right phase too? */
		if((esp->sreg & ESP_STAT_PMASK) == ESP_MIP) {
			/* phew... */
			esp_cmd(esp, eregs, ESP_CMD_TI);
			esp_advance_phase(esp->current_SC, in_msgindone);
			return do_intr_end;
		}

		/* We changed phase but ESP shows bus service,
		 * in this case it is most likely that we, the
		 * hacker who has been up for 20hrs straight
		 * staring at the screen, drowned in coffee
		 * smelling like retched cigarette ashes
		 * have miscoded something..... so, try to
		 * recover as best we can.
		 */
		ESPLOG(("esp%d: message in mis-carriage.\n", esp->esp_id));
	}
	esp_advance_phase(esp->current_SC, in_the_dark);
	return do_phase_determine;
}

static int check_singlebyte_msg(struct NCR_ESP *esp,
				struct ESP_regs *eregs)
{
	esp->prevmsgin = esp->cur_msgin[0];
	if(esp->cur_msgin[0] & 0x80) {
		/* wheee... */
		ESPLOG(("esp%d: target sends identify amidst phases\n",
			esp->esp_id));
		esp_advance_phase(esp->current_SC, in_the_dark);
		return 0;
	} else if(((esp->cur_msgin[0] & 0xf0) == 0x20) ||
		  (esp->cur_msgin[0] == EXTENDED_MESSAGE)) {
		esp->msgin_len = 2;
		esp_advance_phase(esp->current_SC, in_msgincont);
		return 0;
	}
	esp_advance_phase(esp->current_SC, in_the_dark);
	switch(esp->cur_msgin[0]) {
	default:
		/* We don't want to hear about it. */
		ESPLOG(("esp%d: msg %02x which we don't know about\n", esp->esp_id,
			esp->cur_msgin[0]));
		return MESSAGE_REJECT;

	case NOP:
		ESPLOG(("esp%d: target %d sends a nop\n", esp->esp_id,
			esp->current_SC->device->id));
		return 0;

	case RESTORE_POINTERS:
		/* In this case we might also have to backup the
		 * "slow command" pointer.  It is rare to get such
		 * a save/restore pointer sequence so early in the
		 * bus transition sequences, but cover it.
		 */
		if(esp->esp_slowcmd) {
			esp->esp_scmdleft = esp->current_SC->cmd_len;
			esp->esp_scmdp = &esp->current_SC->cmnd[0];
		}
		esp_restore_pointers(esp, esp->current_SC);
		return 0;

	case SAVE_POINTERS:
		esp_save_pointers(esp, esp->current_SC);
		return 0;

	case COMMAND_COMPLETE:
	case DISCONNECT:
		/* Freeing the bus, let it go. */
		esp->current_SC->SCp.phase = in_freeing;
		return 0;

	case MESSAGE_REJECT:
		ESPMISC(("msg reject, "));
		if(esp->prevmsgout == EXTENDED_MESSAGE) {
			struct esp_device *esp_dev = esp->current_SC->device->hostdata;

			/* Doesn't look like this target can
			 * do synchronous or WIDE transfers.
			 */
			ESPSDTR(("got reject, was trying nego, clearing sync/WIDE\n"));
			esp_dev->sync = 1;
			esp_dev->wide = 1;
			esp_dev->sync_min_period = 0;
			esp_dev->sync_max_offset = 0;
			return 0;
		} else {
			ESPMISC(("not sync nego, sending ABORT\n"));
			return ABORT;
		}
	};
}

/* Target negotiates for synchronous transfers before we do, this
 * is legal although very strange.  What is even funnier is that
 * the SCSI2 standard specifically recommends against targets doing
 * this because so many initiators cannot cope with this occurring.
 */
static int target_with_ants_in_pants(struct NCR_ESP *esp,
				     Scsi_Cmnd *SCptr,
				     struct esp_device *esp_dev)
{
	if(esp_dev->sync || SCptr->device->borken) {
		/* sorry, no can do */
		ESPSDTR(("forcing to async, "));
		build_sync_nego_msg(esp, 0, 0);
		esp_dev->sync = 1;
		esp->snip = 1;
		ESPLOG(("esp%d: hoping for msgout\n", esp->esp_id));
		esp_advance_phase(SCptr, in_the_dark);
		return EXTENDED_MESSAGE;
	}

	/* Ok, we'll check them out... */
	return 0;
}

static void sync_report(struct NCR_ESP *esp)
{
	int msg3, msg4;
	char *type;

	msg3 = esp->cur_msgin[3];
	msg4 = esp->cur_msgin[4];
	if(msg4) {
		int hz = 1000000000 / (msg3 * 4);
		int integer = hz / 1000000;
		int fraction = (hz - (integer * 1000000)) / 10000;
		if((msg3 * 4) < 200) {
			type = "FAST";
		} else {
			type = "synchronous";
		}

		/* Do not transform this back into one big printk
		 * again, it triggers a bug in our sparc64-gcc272
		 * sibling call optimization.  -DaveM
		 */
		ESPLOG((KERN_INFO "esp%d: target %d ",
			esp->esp_id, esp->current_SC->device->id));
		ESPLOG(("[period %dns offset %d %d.%02dMHz ",
			(int) msg3 * 4, (int) msg4,
			integer, fraction));
		ESPLOG(("%s SCSI%s]\n", type,
			(((msg3 * 4) < 200) ? "-II" : "")));
	} else {
		ESPLOG((KERN_INFO "esp%d: target %d asynchronous\n",
			esp->esp_id, esp->current_SC->device->id));
	}
}

static int check_multibyte_msg(struct NCR_ESP *esp,
			       struct ESP_regs *eregs)
{
	Scsi_Cmnd *SCptr = esp->current_SC;
	struct esp_device *esp_dev = SCptr->device->hostdata;
	unchar regval = 0;
	int message_out = 0;

	ESPSDTR(("chk multibyte msg: "));
	if(esp->cur_msgin[2] == EXTENDED_SDTR) {
		int period = esp->cur_msgin[3];
		int offset = esp->cur_msgin[4];

		ESPSDTR(("is sync nego response, "));
		if(!esp->snip) {
			int rval;

			/* Target negotiates first! */
			ESPSDTR(("target jumps the gun, "));
			message_out = EXTENDED_MESSAGE; /* we must respond */
			rval = target_with_ants_in_pants(esp, SCptr, esp_dev);
			if(rval)
				return rval;
		}

		ESPSDTR(("examining sdtr, "));

		/* Offset cannot be larger than ESP fifo size. */
		if(offset > 15) {
			ESPSDTR(("offset too big %2x, ", offset));
			offset = 15;
			ESPSDTR(("sending back new offset\n"));
			build_sync_nego_msg(esp, period, offset);
			return EXTENDED_MESSAGE;
		}

		if(offset && period > esp->max_period) {
			/* Yeee, async for this slow device. */
			ESPSDTR(("period too long %2x, ", period));
			build_sync_nego_msg(esp, 0, 0);
			ESPSDTR(("hoping for msgout\n"));
			esp_advance_phase(esp->current_SC, in_the_dark);
			return EXTENDED_MESSAGE;
		} else if (offset && period < esp->min_period) {
			ESPSDTR(("period too short %2x, ", period));
			period = esp->min_period;
			if(esp->erev > esp236)
				regval = 4;
			else
				regval = 5;
		} else if(offset) {
			int tmp;

			ESPSDTR(("period is ok, "));
			tmp = esp->ccycle / 1000;
			regval = (((period << 2) + tmp - 1) / tmp);
			if(regval && (esp->erev > esp236)) {
				if(period >= 50)
					regval--;
			}
		}

		if(offset) {
			unchar bit;

			esp_dev->sync_min_period = (regval & 0x1f);
			esp_dev->sync_max_offset = (offset | esp->radelay);
			if(esp->erev > esp236) {
				if(esp->erev == fas100a)
					bit = ESP_CONFIG3_FAST;
				else
					bit = ESP_CONFIG3_FSCSI;
				if(period < 50)
					esp->config3[SCptr->device->id] |= bit;
				else
					esp->config3[SCptr->device->id] &= ~bit;
				esp->prev_cfg3 = esp->config3[SCptr->device->id];
				esp_write(eregs->esp_cfg3, esp->prev_cfg3);
			}
			esp->prev_soff = esp_dev->sync_min_period;
			esp_write(eregs->esp_soff, esp->prev_soff);
			esp->prev_stp = esp_dev->sync_max_offset;
			esp_write(eregs->esp_stp, esp->prev_stp);

			ESPSDTR(("soff=%2x stp=%2x cfg3=%2x\n",
				esp_dev->sync_max_offset,
				esp_dev->sync_min_period,
				esp->config3[scmd_id(SCptr)]));

			esp->snip = 0;
		} else if(esp_dev->sync_max_offset) {
			unchar bit;

			/* back to async mode */
			ESPSDTR(("unaccaptable sync nego, forcing async\n"));
			esp_dev->sync_max_offset = 0;
			esp_dev->sync_min_period = 0;
			esp->prev_soff = 0;
			esp_write(eregs->esp_soff, 0);
			esp->prev_stp = 0;
			esp_write(eregs->esp_stp, 0);
			if(esp->erev > esp236) {
				if(esp->erev == fas100a)
					bit = ESP_CONFIG3_FAST;
				else
					bit = ESP_CONFIG3_FSCSI;
				esp->config3[SCptr->device->id] &= ~bit;
				esp->prev_cfg3 = esp->config3[SCptr->device->id];
				esp_write(eregs->esp_cfg3, esp->prev_cfg3);
			}
		}

		sync_report(esp);

		ESPSDTR(("chk multibyte msg: sync is known, "));
		esp_dev->sync = 1;

		if(message_out) {
			ESPLOG(("esp%d: sending sdtr back, hoping for msgout\n",
				esp->esp_id));
			build_sync_nego_msg(esp, period, offset);
			esp_advance_phase(SCptr, in_the_dark);
			return EXTENDED_MESSAGE;
		}

		ESPSDTR(("returning zero\n"));
		esp_advance_phase(SCptr, in_the_dark); /* ...or else! */
		return 0;
	} else if(esp->cur_msgin[2] == EXTENDED_WDTR) {
		ESPLOG(("esp%d: AIEEE wide msg received\n", esp->esp_id));
		message_out = MESSAGE_REJECT;
	} else if(esp->cur_msgin[2] == EXTENDED_MODIFY_DATA_POINTER) {
		ESPLOG(("esp%d: rejecting modify data ptr msg\n", esp->esp_id));
		message_out = MESSAGE_REJECT;
	}
	esp_advance_phase(SCptr, in_the_dark);
	return message_out;
}

static int esp_do_msgindone(struct NCR_ESP *esp, struct ESP_regs *eregs)
{
	Scsi_Cmnd *SCptr = esp->current_SC;
	int message_out = 0, it = 0, rval;

	rval = skipahead1(esp, eregs, SCptr, in_msgin, in_msgindone);
	if(rval)
		return rval;
	if(SCptr->SCp.sent_command != in_status) {
		if(!(esp->ireg & ESP_INTR_DC)) {
			if(esp->msgin_len && (esp->sreg & ESP_STAT_PERR)) {
				message_out = MSG_PARITY_ERROR;
				esp_cmd(esp, eregs, ESP_CMD_FLUSH);
			} else if((it = (esp_read(eregs->esp_fflags) & ESP_FF_FBYTES))!=1) {
				/* We certainly dropped the ball somewhere. */
				message_out = INITIATOR_ERROR;
				esp_cmd(esp, eregs, ESP_CMD_FLUSH);
			} else if(!esp->msgin_len) {
				it = esp_read(eregs->esp_fdata);
				esp_advance_phase(SCptr, in_msgincont);
			} else {
				/* it is ok and we want it */
				it = esp->cur_msgin[esp->msgin_ctr] =
					esp_read(eregs->esp_fdata);
				esp->msgin_ctr++;
			}
		} else {
			esp_advance_phase(SCptr, in_the_dark);
			return do_work_bus;
		}
	} else {
		it = esp->cur_msgin[0];
	}
	if(!message_out && esp->msgin_len) {
		if(esp->msgin_ctr < esp->msgin_len) {
			esp_advance_phase(SCptr, in_msgincont);
		} else if(esp->msgin_len == 1) {
			message_out = check_singlebyte_msg(esp, eregs);
		} else if(esp->msgin_len == 2) {
			if(esp->cur_msgin[0] == EXTENDED_MESSAGE) {
				if((it+2) >= 15) {
					message_out = MESSAGE_REJECT;
				} else {
					esp->msgin_len = (it + 2);
					esp_advance_phase(SCptr, in_msgincont);
				}
			} else {
				message_out = MESSAGE_REJECT; /* foo on you */
			}
		} else {
			message_out = check_multibyte_msg(esp, eregs);
		}
	}
	if(message_out < 0) {
		return -message_out;
	} else if(message_out) {
		if(((message_out != 1) &&
		    ((message_out < 0x20) || (message_out & 0x80))))
			esp->msgout_len = 1;
		esp->cur_msgout[0] = message_out;
		esp_cmd(esp, eregs, ESP_CMD_SATN);
		esp_advance_phase(SCptr, in_the_dark);
		esp->msgin_len = 0;
	}
	esp->sreg = esp_read(eregs->esp_status);
	esp->sreg &= ~(ESP_STAT_INTR);
	if((esp->sreg & (ESP_STAT_PMSG|ESP_STAT_PCD)) == (ESP_STAT_PMSG|ESP_STAT_PCD))
		esp_cmd(esp, eregs, ESP_CMD_MOK);
	if((SCptr->SCp.sent_command == in_msgindone) &&
	    (SCptr->SCp.phase == in_freeing))
		return esp_do_freebus(esp, eregs);
	return do_intr_end;
}

static int esp_do_cmdbegin(struct NCR_ESP *esp, struct ESP_regs *eregs)
{
	unsigned char tmp;
	Scsi_Cmnd *SCptr = esp->current_SC;

	esp_advance_phase(SCptr, in_cmdend);
	esp_cmd(esp, eregs, ESP_CMD_FLUSH);
	tmp = *esp->esp_scmdp++;
	esp->esp_scmdleft--;
	esp_write(eregs->esp_fdata, tmp);
	esp_cmd(esp, eregs, ESP_CMD_TI);
	return do_intr_end;
}

static int esp_do_cmddone(struct NCR_ESP *esp, struct ESP_regs *eregs)
{
	esp_cmd(esp, eregs, ESP_CMD_NULL);
	if(esp->ireg & ESP_INTR_BSERV) {
		esp_advance_phase(esp->current_SC, in_the_dark);
		return esp_do_phase_determine(esp, eregs);
	}
	ESPLOG(("esp%d: in do_cmddone() but didn't get BSERV interrupt.\n",
		esp->esp_id));
	return do_reset_bus;
}

static int esp_do_msgout(struct NCR_ESP *esp, struct ESP_regs *eregs)
{
	esp_cmd(esp, eregs, ESP_CMD_FLUSH);
	switch(esp->msgout_len) {
	case 1:
		esp_write(eregs->esp_fdata, esp->cur_msgout[0]);
		esp_cmd(esp, eregs, ESP_CMD_TI);
		break;

	case 2:
		if(esp->do_pio_cmds){
			esp_write(eregs->esp_fdata, esp->cur_msgout[0]);
			esp_write(eregs->esp_fdata, esp->cur_msgout[1]);
			esp_cmd(esp, eregs, ESP_CMD_TI);
		} else {
			esp->esp_command[0] = esp->cur_msgout[0];
			esp->esp_command[1] = esp->cur_msgout[1];
			esp->dma_setup(esp, esp->esp_command_dvma, 2, 0);
			esp_setcount(eregs, 2);
			esp_cmd(esp, eregs, ESP_CMD_DMA | ESP_CMD_TI);
		}
		break;

	case 4:
		esp->snip = 1;
		if(esp->do_pio_cmds){
			esp_write(eregs->esp_fdata, esp->cur_msgout[0]);
			esp_write(eregs->esp_fdata, esp->cur_msgout[1]);
			esp_write(eregs->esp_fdata, esp->cur_msgout[2]);
			esp_write(eregs->esp_fdata, esp->cur_msgout[3]);
			esp_cmd(esp, eregs, ESP_CMD_TI);
		} else {
			esp->esp_command[0] = esp->cur_msgout[0];
			esp->esp_command[1] = esp->cur_msgout[1];
			esp->esp_command[2] = esp->cur_msgout[2];
			esp->esp_command[3] = esp->cur_msgout[3];
			esp->dma_setup(esp, esp->esp_command_dvma, 4, 0);
			esp_setcount(eregs, 4);
			esp_cmd(esp, eregs, ESP_CMD_DMA | ESP_CMD_TI);
		}
		break;

	case 5:
		esp->snip = 1;
		if(esp->do_pio_cmds){
			esp_write(eregs->esp_fdata, esp->cur_msgout[0]);
			esp_write(eregs->esp_fdata, esp->cur_msgout[1]);
			esp_write(eregs->esp_fdata, esp->cur_msgout[2]);
			esp_write(eregs->esp_fdata, esp->cur_msgout[3]);
			esp_write(eregs->esp_fdata, esp->cur_msgout[4]);
			esp_cmd(esp, eregs, ESP_CMD_TI);
		} else {
			esp->esp_command[0] = esp->cur_msgout[0];
			esp->esp_command[1] = esp->cur_msgout[1];
			esp->esp_command[2] = esp->cur_msgout[2];
			esp->esp_command[3] = esp->cur_msgout[3];
			esp->esp_command[4] = esp->cur_msgout[4];
			esp->dma_setup(esp, esp->esp_command_dvma, 5, 0);
			esp_setcount(eregs, 5);
			esp_cmd(esp, eregs, ESP_CMD_DMA | ESP_CMD_TI);
		}
		break;

	default:
		/* whoops */
		ESPMISC(("bogus msgout sending NOP\n"));
		esp->cur_msgout[0] = NOP;
		esp_write(eregs->esp_fdata, esp->cur_msgout[0]);
		esp->msgout_len = 1;
		esp_cmd(esp, eregs, ESP_CMD_TI);
		break;
	}
	esp_advance_phase(esp->current_SC, in_msgoutdone);
	return do_intr_end;
}

static int esp_do_msgoutdone(struct NCR_ESP *esp, 
			     struct ESP_regs *eregs)
{
	if((esp->msgout_len > 1) && esp->dma_barrier)
		esp->dma_barrier(esp);

	if(!(esp->ireg & ESP_INTR_DC)) {
		esp_cmd(esp, eregs, ESP_CMD_NULL);
		switch(esp->sreg & ESP_STAT_PMASK) {
		case ESP_MOP:
			/* whoops, parity error */
			ESPLOG(("esp%d: still in msgout, parity error assumed\n",
				esp->esp_id));
			if(esp->msgout_len > 1)
				esp_cmd(esp, eregs, ESP_CMD_SATN);
			esp_advance_phase(esp->current_SC, in_msgout);
			return do_work_bus;

		case ESP_DIP:
			break;

		default:
			if(!fcount(esp, eregs) &&
			   !(((struct esp_device *)esp->current_SC->device->hostdata)->sync_max_offset))
				esp_cmd(esp, eregs, ESP_CMD_FLUSH);
			break;

		};
	}

	/* If we sent out a synchronous negotiation message, update
	 * our state.
	 */
	if(esp->cur_msgout[2] == EXTENDED_MESSAGE &&
	   esp->cur_msgout[4] == EXTENDED_SDTR) {
		esp->snip = 1; /* anal retentiveness... */
	}

	esp->prevmsgout = esp->cur_msgout[0];
	esp->msgout_len = 0;
	esp_advance_phase(esp->current_SC, in_the_dark);
	return esp_do_phase_determine(esp, eregs);
}

static int esp_bus_unexpected(struct NCR_ESP *esp, struct ESP_regs *eregs)
{
	ESPLOG(("esp%d: command in weird state %2x\n",
		esp->esp_id, esp->current_SC->SCp.phase));
	return do_reset_bus;
}

static espfunc_t bus_vector[] = {
	esp_do_data_finale,
	esp_do_data_finale,
	esp_bus_unexpected,
	esp_do_msgin,
	esp_do_msgincont,
	esp_do_msgindone,
	esp_do_msgout,
	esp_do_msgoutdone,
	esp_do_cmdbegin,
	esp_do_cmddone,
	esp_do_status,
	esp_do_freebus,
	esp_do_phase_determine,
	esp_bus_unexpected,
	esp_bus_unexpected,
	esp_bus_unexpected,
};

/* This is the second tier in our dual-level SCSI state machine. */
static int esp_work_bus(struct NCR_ESP *esp, struct ESP_regs *eregs)
{
	Scsi_Cmnd *SCptr = esp->current_SC;
	unsigned int phase;

	ESPBUS(("esp_work_bus: "));
	if(!SCptr) {
		ESPBUS(("reconnect\n"));
		return esp_do_reconnect(esp, eregs);
	}
	phase = SCptr->SCp.phase;
	if ((phase & 0xf0) == in_phases_mask)
		return bus_vector[(phase & 0x0f)](esp, eregs);
	else if((phase & 0xf0) == in_slct_mask)
		return esp_select_complete(esp, eregs);
	else
		return esp_bus_unexpected(esp, eregs);
}

static espfunc_t isvc_vector[] = {
	NULL,
	esp_do_phase_determine,
	esp_do_resetbus,
	esp_finish_reset,
	esp_work_bus
};

/* Main interrupt handler for an esp adapter. */
void esp_handle(struct NCR_ESP *esp)
{
	struct ESP_regs *eregs;
	Scsi_Cmnd *SCptr;
	int what_next = do_intr_end;
	eregs = esp->eregs;
	SCptr = esp->current_SC;

	if(esp->dma_irq_entry)
		esp->dma_irq_entry(esp);

	/* Check for errors. */
	esp->sreg = esp_read(eregs->esp_status);
	esp->sreg &= (~ESP_STAT_INTR);
	esp->seqreg = (esp_read(eregs->esp_sstep) & ESP_STEP_VBITS);
	esp->ireg = esp_read(eregs->esp_intrpt);   /* Unlatch intr and stat regs */
	ESPIRQ(("handle_irq: [sreg<%02x> sstep<%02x> ireg<%02x>]\n",
		esp->sreg, esp->seqreg, esp->ireg));
	if(esp->sreg & (ESP_STAT_SPAM)) {
		/* Gross error, could be due to one of:
		 *
		 * - top of fifo overwritten, could be because
		 *   we tried to do a synchronous transfer with
		 *   an offset greater than ESP fifo size
		 *
		 * - top of command register overwritten
		 *
		 * - DMA setup to go in one direction, SCSI
		 *   bus points in the other, whoops
		 *
		 * - weird phase change during asynchronous
		 *   data phase while we are initiator
		 */
		ESPLOG(("esp%d: Gross error sreg=%2x\n", esp->esp_id, esp->sreg));

		/* If a command is live on the bus we cannot safely
		 * reset the bus, so we'll just let the pieces fall
		 * where they may.  Here we are hoping that the
		 * target will be able to cleanly go away soon
		 * so we can safely reset things.
		 */
		if(!SCptr) {
			ESPLOG(("esp%d: No current cmd during gross error, "
				"resetting bus\n", esp->esp_id));
			what_next = do_reset_bus;
			goto state_machine;
		}
	}

	/* No current cmd is only valid at this point when there are
	 * commands off the bus or we are trying a reset.
	 */
	if(!SCptr && !esp->disconnected_SC && !(esp->ireg & ESP_INTR_SR)) {
		/* Panic is safe, since current_SC is null. */
		ESPLOG(("esp%d: no command in esp_handle()\n", esp->esp_id));
		panic("esp_handle: current_SC == penguin within interrupt!");
	}

	if(esp->ireg & (ESP_INTR_IC)) {
		/* Illegal command fed to ESP.  Outside of obvious
		 * software bugs that could cause this, there is
		 * a condition with ESP100 where we can confuse the
		 * ESP into an erroneous illegal command interrupt
		 * because it does not scrape the FIFO properly
		 * for reselection.  See esp100_reconnect_hwbug()
		 * to see how we try very hard to avoid this.
		 */
		ESPLOG(("esp%d: invalid command\n", esp->esp_id));

		esp_dump_state(esp, eregs);

		if(SCptr) {
			/* Devices with very buggy firmware can drop BSY
			 * during a scatter list interrupt when using sync
			 * mode transfers.  We continue the transfer as
			 * expected, the target drops the bus, the ESP
			 * gets confused, and we get a illegal command
			 * interrupt because the bus is in the disconnected
			 * state now and ESP_CMD_TI is only allowed when
			 * a nexus is alive on the bus.
			 */
			ESPLOG(("esp%d: Forcing async and disabling disconnect for "
				"target %d\n", esp->esp_id, SCptr->device->id));
			SCptr->device->borken = 1; /* foo on you */
		}

		what_next = do_reset_bus;
	} else if(!(esp->ireg & ~(ESP_INTR_FDONE | ESP_INTR_BSERV | ESP_INTR_DC))) {
		int phase;

		if(SCptr) {
			phase = SCptr->SCp.phase;
			if(phase & in_phases_mask) {
				what_next = esp_work_bus(esp, eregs);
			} else if(phase & in_slct_mask) {
				what_next = esp_select_complete(esp, eregs);
			} else {
				ESPLOG(("esp%d: interrupt for no good reason...\n",
					esp->esp_id));
				what_next = do_intr_end;
			}
		} else {
			ESPLOG(("esp%d: BSERV or FDONE or DC while SCptr==NULL\n",
				esp->esp_id));
			what_next = do_reset_bus;
		}
	} else if(esp->ireg & ESP_INTR_SR) {
		ESPLOG(("esp%d: SCSI bus reset interrupt\n", esp->esp_id));
		what_next = do_reset_complete;
	} else if(esp->ireg & (ESP_INTR_S | ESP_INTR_SATN)) {
		ESPLOG(("esp%d: AIEEE we have been selected by another initiator!\n",
			esp->esp_id));
		what_next = do_reset_bus;
	} else if(esp->ireg & ESP_INTR_RSEL) {
		if(!SCptr) {
			/* This is ok. */
			what_next = esp_do_reconnect(esp, eregs);
		} else if(SCptr->SCp.phase & in_slct_mask) {
			/* Only selection code knows how to clean
			 * up properly.
			 */
			ESPDISC(("Reselected during selection attempt\n"));
			what_next = esp_select_complete(esp, eregs);
		} else {
			ESPLOG(("esp%d: Reselected while bus is busy\n",
				esp->esp_id));
			what_next = do_reset_bus;
		}
	}

	/* This is tier-one in our dual level SCSI state machine. */
state_machine:
	while(what_next != do_intr_end) {
		if (what_next >= do_phase_determine &&
		    what_next < do_intr_end)
			what_next = isvc_vector[what_next](esp, eregs);
		else {
			/* state is completely lost ;-( */
			ESPLOG(("esp%d: interrupt engine loses state, resetting bus\n",
				esp->esp_id));
			what_next = do_reset_bus;
		}
	}
	if(esp->dma_irq_exit)
		esp->dma_irq_exit(esp);
}

#ifndef CONFIG_SMP
irqreturn_t esp_intr(int irq, void *dev_id, struct pt_regs *pregs)
{
	struct NCR_ESP *esp;
	unsigned long flags;
	int again;
	struct Scsi_Host *dev = dev_id;

	/* Handle all ESP interrupts showing at this IRQ level. */
	spin_lock_irqsave(dev->host_lock, flags);
repeat:
	again = 0;
	for_each_esp(esp) {
#ifndef __mips__	    
		if(((esp)->irq & 0xff) == irq) {
#endif		    
			if(esp->dma_irq_p(esp)) {
				again = 1;

				esp->dma_ints_off(esp);

				ESPIRQ(("I%d(", esp->esp_id));
				esp_handle(esp);
				ESPIRQ((")"));

				esp->dma_ints_on(esp);
			}
#ifndef __mips__		    
		}
#endif	    
	}
	if(again)
		goto repeat;
	spin_unlock_irqrestore(dev->host_lock, flags);
	return IRQ_HANDLED;
}
#else
/* For SMP we only service one ESP on the list list at our IRQ level! */
irqreturn_t esp_intr(int irq, void *dev_id, struct pt_regs *pregs)
{
	struct NCR_ESP *esp;
	unsigned long flags;
	struct Scsi_Host *dev = dev_id;
	
	/* Handle all ESP interrupts showing at this IRQ level. */
	spin_lock_irqsave(dev->host_lock, flags);
	for_each_esp(esp) {
		if(((esp)->irq & 0xf) == irq) {
			if(esp->dma_irq_p(esp)) {
				esp->dma_ints_off(esp);

				ESPIRQ(("I[%d:%d](",
					smp_processor_id(), esp->esp_id));
				esp_handle(esp);
				ESPIRQ((")"));

				esp->dma_ints_on(esp);
				goto out;
			}
		}
	}
out:
	spin_unlock_irqrestore(dev->host_lock, flags);
	return IRQ_HANDLED;
}
#endif

int esp_slave_alloc(struct scsi_device *SDptr)
{
	struct esp_device *esp_dev =
		kmalloc(sizeof(struct esp_device), GFP_ATOMIC);

	if (!esp_dev)
		return -ENOMEM;
	memset(esp_dev, 0, sizeof(struct esp_device));
	SDptr->hostdata = esp_dev;
	return 0;
}

void esp_slave_destroy(struct scsi_device *SDptr)
{
	struct NCR_ESP *esp = (struct NCR_ESP *) SDptr->host->hostdata;

	esp->targets_present &= ~(1 << sdev_id(SDptr));
	kfree(SDptr->hostdata);
	SDptr->hostdata = NULL;
}

#ifdef MODULE
int init_module(void) { return 0; }
void cleanup_module(void) {}
void esp_release(void)
{
	esps_in_use--;
	esps_running = esps_in_use;
}
#endif

EXPORT_SYMBOL(esp_abort);
EXPORT_SYMBOL(esp_allocate);
EXPORT_SYMBOL(esp_deallocate);
EXPORT_SYMBOL(esp_initialize);
EXPORT_SYMBOL(esp_intr);
EXPORT_SYMBOL(esp_queue);
EXPORT_SYMBOL(esp_reset);
EXPORT_SYMBOL(esp_slave_alloc);
EXPORT_SYMBOL(esp_slave_destroy);
EXPORT_SYMBOL(esps_in_use);

MODULE_LICENSE("GPL");