#include <linux/config.h>
#include <linux/delay.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/pci.h>
#include <linux/string.h>
#include <linux/blk.h>
#include <linux/init.h>

#include <asm/io.h>
#include <asm/system.h>
#include <asm/spinlock.h>

#include "scsi.h"
#include "hosts.h"
#include "AM53C974.h"
#include "constants.h"
#include "sd.h"

/* AM53/79C974 (PCscsi) driver release 0.5
 *
 * The architecture and much of the code of this device
 * driver was originally developed by Drew Eckhardt for
 * the NCR5380. The following copyrights apply:
 *  For the architecture and all pieces of code which can also be found 
 *    in the NCR5380 device driver:
 *   Copyright 1993, Drew Eckhardt
 *	Visionary Computing 
 *	(Unix and Linux consulting and custom programming)
 * 	drew@colorado.edu
 *	+1 (303) 666-5836
 *
 *  The AM53C974_nobios_detect code was originally developed by
 *   Robin Cutshaw (robin@xfree86.org) and is used here in a 
 *   slightly modified form.
 *
 *  PCI detection rewritten by Martin Mares <mj@atrey.karlin.mff.cuni.cz>
 *
 *  For the remaining code:
 *    Copyright 1994, D. Frieauff
 *    EMail: fri@rsx42sun0.dofn.de
 *    Phone: x49-7545-8-2256 , x49-7541-42305
 */

/*
 * $Log: AM53C974.c,v $
 */

#ifdef AM53C974_DEBUG
 #define DEB(x) x
 #ifdef AM53C974_DEBUG_KEYWAIT
   #define KEYWAIT() AM53C974_keywait()
  #else
   #define KEYWAIT()
  #endif
 #ifdef AM53C974_DEBUG_INIT
   #define DEB_INIT(x) x
  #else
   #define DEB_INIT(x)
  #endif
 #ifdef AM53C974_DEBUG_MSG
   #define DEB_MSG(x) x
  #else
   #define DEB_MSG(x)
  #endif
 #ifdef AM53C974_DEB_RESEL
   #define DEB_RESEL(x) x
  #else
   #define DEB_RESEL(x)
  #endif
 #ifdef AM53C974_DEBUG_QUEUE
  #define DEB_QUEUE(x) x
  #define LIST(x,y) {printk("LINE:%d   Adding %p to %p\n", __LINE__, (void*)(x), (void*)(y)); if ((x)==(y)) udelay(5); }
  #define REMOVE(w,x,y,z) {printk("LINE:%d   Removing: %p->%p  %p->%p \n", __LINE__, (void*)(w), (void*)(x), (void*)(y), (void*)(z)); if ((x)==(y)) udelay(5); }
 #else
  #define DEB_QUEUE(x)
  #define LIST(x,y)
  #define REMOVE(w,x,y,z)
 #endif
 #ifdef AM53C974_DEBUG_INFO
   #define DEB_INFO(x) x
  #else
   #define DEB_INFO(x)
  #endif
 #ifdef AM53C974_DEBUG_LINKED
   #define DEB_LINKED(x) x
  #else
   #define DEB_LINKED(x)
  #endif
 #ifdef AM53C974_DEBUG_INTR
   #define DEB_INTR(x) x
  #else
   #define DEB_INTR(x)
  #endif
#else
 #define DEB_INIT(x)
 #define DEB(x)
 #define DEB_QUEUE(x)
 #define LIST(x,y)
 #define REMOVE(w,x,y,z)
 #define DEB_INFO(x)
 #define DEB_LINKED(x)
 #define DEB_INTR(x)
 #define DEB_MSG(x)
 #define DEB_RESEL(x)
 #define KEYWAIT()
#endif
 #ifdef AM53C974_DEBUG_ABORT
   #define DEB_ABORT(x) x
  #else
   #define DEB_ABORT(x)
  #endif

#ifdef VERBOSE_AM53C974_DEBUG
#define VDEB(x) x
#else
#define VDEB(x)
#endif

#define INSIDE(x,l,h) ( ((x) >= (l)) && ((x) <= (h)) )


#include <scsi/scsicam.h>

/***************************************************************************************
* Default setting of the controller's SCSI id. Edit and uncomment this only if your    *
* BIOS does not correctly initialize the controller's SCSI id.                         *
* If you don't get a warning during boot, it is correctly initialized.                 *
****************************************************************************************/
/* #define AM53C974_SCSI_ID 7 */

/***************************************************************************************
* Default settings for sync. negotiation enable, transfer rate and sync. offset.       *
* These settings can be replaced by LILO overrides (append) with the following syntax:          *
* AM53C974=host-scsi-id, target-scsi-id, max-rate, max-offset                          *
* Sync. negotiation is disabled by default and will be enabled for those targets which *
* are specified in the LILO override                                                   *
****************************************************************************************/
#define DEFAULT_SYNC_NEGOTIATION_ENABLED 0 /* 0 or 1 */
#define DEFAULT_RATE			 5 /* MHz, min: 3; max: 10 */
#define DEFAULT_SYNC_OFFSET		 0 /* bytes, min: 0; max: 15; use 0 for async. mode */

/***************************************************************************************
* If defined, don't allow targets to disconnect during commands.  This will reduce     *
* performance, but may be worthwhile if you suspect the driver of corrupting data when *
* a disconnect happens.                                                                *
***************************************************************************************/
#define AM53C974_PROHIBIT_DISCONNECT

/* --------------------- don't edit below here  --------------------- */

#define AM53C974_DRIVER_REVISION_MAJOR 0
#define AM53C974_DRIVER_REVISION_MINOR 5
#define SEPARATOR_LINE  \
"--------------------------------------------------------------------------\n"

/* debug control */
/* #define AM53C974_DEBUG */
/* #define AM53C974_DEBUG_MSG */
/* #define AM53C974_DEBUG_KEYWAIT */
/* #define AM53C974_DEBUG_INIT */
/* #define AM53C974_DEBUG_QUEUE */
/* #define AM53C974_DEBUG_INFO */
/* #define AM53C974_DEBUG_LINKED */
/* #define VERBOSE_AM53C974_DEBUG */
/* #define AM53C974_DEBUG_INTR */
/* #define AM53C974_DEB_RESEL */
#define AM53C974_DEBUG_ABORT
/* #define AM53C974_OPTION_DEBUG_PROBE_ONLY */

/* special options/constants */
#define DEF_CLK                 40   /* chip clock freq. in MHz */
#define MIN_PERIOD               4   /* for negotiation: min. number of clocks per cycle */
#define MAX_PERIOD              13   /* for negotiation: max. number of clocks per cycle */
#define MAX_OFFSET              15   /* for negotiation: max. offset (0=async) */

#define DEF_SCSI_TIMEOUT        245  /* STIMREG value, 40 Mhz */
#define DEF_STP                 8    /* STPREG value assuming 5.0 MB/sec, FASTCLK, FASTSCSI */
#define DEF_SOF_RAD             0    /* REQ/ACK deassertion delay */
#define DEF_SOF_RAA             0    /* REQ/ACK assertion delay */
#define DEF_ETM                 0    /* CNTLREG1, ext. timing mode */
#define DEF_PERE                1    /* CNTLREG1, parity error reporting */
#define DEF_CLKF                0    /* CLKFREG,  0=40 Mhz */
#define DEF_ENF                 1    /* CNTLREG2, enable features */
#define DEF_ADIDCHK             0    /* CNTLREG3, additional ID check */
#define DEF_FASTSCSI            1    /* CNTLREG3, fast SCSI */
#define DEF_FASTCLK             1    /* CNTLREG3, fast clocking, 5 MB/sec at 40MHz chip clk */
#define DEF_GLITCH              1    /* CNTLREG4, glitch eater, 0=12ns, 1=35ns, 2=25ns, 3=off */
#define DEF_PWD                 0    /* CNTLREG4, reduced power feature */
#define DEF_RAE                 0    /* CNTLREG4, RAE active negation on REQ, ACK only */
#define DEF_RADE                1    /* 1CNTLREG4, active negation on REQ, ACK and data */

/*** SCSI block ***/
#define CTCLREG		    	0x00	/* r	current transf. count, low byte    */
#define CTCMREG		   	0x04	/* r 	current transf. count, middle byte */
#define CTCHREG		    	0x38	/* r	current transf. count, high byte   */
#define STCLREG		    	0x00	/* w	start transf. count, low byte      */
#define STCMREG		    	0x04	/* w	start transf. count, middle byte   */
#define STCHREG		    	0x38	/* w 	start transf. count, high byte     */
#define FFREG		    	0x08	/* rw	SCSI FIFO reg.			   */
#define STIMREG		    	0x14	/* w	SCSI timeout reg.		   */

#define SDIDREG		    	0x10	/* w	SCSI destination ID reg.	   */
#define SDIREG_MASK		0x07	/* mask					   */

#define STPREG		    	0x18	/* w	synchronous transf. period reg.	   */
#define STPREG_STP		0x1F	/* synchr. transfer period		   */

#define CLKFREG		    	0x24	/* w	clock factor reg.		   */
#define CLKFREG_MASK		0x07	/* mask					   */

#define CMDREG		    	0x0C	/* rw	SCSI command reg.		   */
#define CMDREG_DMA         	0x80    /* set DMA mode (set together with opcodes below) */
#define CMDREG_IT          	0x10    /* information transfer 		   */
#define CMDREG_ICCS		0x11	/* initiator command complete steps 	   */
#define CMDREG_MA		0x12	/* message accepted 			   */
#define CMDREG_TPB		0x98	/* transfer pad bytes, DMA mode only 	   */
#define CMDREG_SATN		0x1A	/* set ATN 				   */
#define CMDREG_RATN		0x1B	/* reset ATN 				   */
#define CMDREG_SOAS		0x41	/* select without ATN steps 		   */
#define CMDREG_SAS		0x42	/* select with ATN steps (1 msg byte)	   */
#define CMDREG_SASS		0x43	/* select with ATN and stop steps 	   */
#define CMDREG_ESR		0x44	/* enable selection/reselection 	   */
#define CMDREG_DSR		0x45	/* disable selection/reselection 	   */
#define CMDREG_SA3S		0x46	/* select with ATN 3 steps  (3 msg bytes)  */
#define CMDREG_NOP		0x00	/* no operation 			   */
#define CMDREG_CFIFO		0x01	/* clear FIFO 				   */
#define CMDREG_RDEV		0x02	/* reset device 			   */
#define CMDREG_RBUS		0x03	/* reset SCSI bus 			   */

#define STATREG		    	0x10	/* r 	SCSI status reg.		   */
#define STATREG_INT		0x80	/* SCSI interrupt condition detected	   */
#define STATREG_IOE		0x40	/* SCSI illegal operation error detected   */
#define STATREG_PE		0x20	/* SCSI parity error detected		   */
#define STATREG_CTZ		0x10	/* CTC reg decremented to zero		   */
#define STATREG_MSG		0x04	/* SCSI MSG phase (latched?)		   */
#define STATREG_CD		0x02	/* SCSI C/D phase (latched?)		   */
#define STATREG_IO		0x01	/* SCSI I/O phase (latched?)		   */
#define STATREG_PHASE           0x07    /* SCSI phase mask 			   */

#define INSTREG		    	0x14	/* r	interrupt status reg.		   */
#define INSTREG_SRST		0x80	/* SCSI reset detected			   */
#define INSTREG_ICMD		0x40	/* SCSI invalid command detected	   */
#define INSTREG_DIS		0x20	/* target disconnected or sel/resel timeout*/
#define INSTREG_SR		0x10	/* device on bus has service request       */
#define INSTREG_SO		0x08	/* successful operation			   */
#define INSTREG_RESEL		0x04	/* device reselected as initiator	   */

#define ISREG		    	0x18	/* r	internal state reg.		   */
#define ISREG_SOF		0x08	/* synchronous offset flag (act. low)	   */
#define ISREG_IS		0x07	/* status of intermediate op.		   */
#define ISREG_OK_NO_STOP        0x04    /* selection successful                    */
#define ISREG_OK_STOP           0x01    /* selection successful                    */

#define CFIREG		    	0x1C	/* r	current FIFO/internal state reg.   */
#define CFIREG_IS		0xE0	/* status of intermediate op.		   */
#define CFIREG_CF		0x1F	/* number of bytes in SCSI FIFO		   */

#define SOFREG		    	0x1C	/* w	synchr. offset reg.		   */
#define SOFREG_RAD		0xC0	/* REQ/ACK deassertion delay (sync.)	   */
#define SOFREG_RAA		0x30	/* REQ/ACK assertion delay (sync.)	   */
#define SOFREG_SO		0x0F	/* synch. offset (sync.)		   */

#define CNTLREG1	    	0x20	/* rw	control register one		   */
#define CNTLREG1_ETM		0x80	/* set extended timing mode		   */
#define CNTLREG1_DISR		0x40	/* disable interrupt on SCSI reset	   */
#define CNTLREG1_PERE		0x10	/* enable parity error reporting	   */
#define CNTLREG1_SID		0x07	/* host adapter SCSI ID			   */

#define CNTLREG2	    	0x2C	/* rw	control register two		   */
#define CNTLREG2_ENF		0x40	/* enable features			   */

#define CNTLREG3	    	0x30	/* rw	control register three		   */
#define CNTLREG3_ADIDCHK	0x80	/* additional ID check			   */
#define CNTLREG3_FASTSCSI	0x10	/* fast SCSI				   */
#define CNTLREG3_FASTCLK	0x08	/* fast SCSI clocking			   */

#define CNTLREG4	    	0x34	/* rw	control register four		   */
#define CNTLREG4_GLITCH		0xC0	/* glitch eater				   */
#define CNTLREG4_PWD		0x20	/* reduced power feature		   */
#define CNTLREG4_RAE		0x08	/* write only, active negot. ctrl.	   */
#define CNTLREG4_RADE		0x04	/* active negot. ctrl.			   */
#define CNTLREG4_RES		0x10	/* reserved bit, must be 1		   */

/*** DMA block ***/
#define DMACMD		    	0x40	/* rw	command				   */
#define DMACMD_DIR		0x80	/* transfer direction (1=read from device) */
#define DMACMD_INTE_D		0x40	/* DMA transfer interrupt enable 	   */
#define DMACMD_INTE_P		0x20	/* page transfer interrupt enable 	   */
#define DMACMD_MDL		0x10	/* map to memory descriptor list 	   */
#define DMACMD_DIAG		0x04	/* diagnostics, set to 0		   */
#define DMACMD_IDLE 		0x00	/* idle cmd			 	   */
#define DMACMD_BLAST		0x01	/* flush FIFO to memory		 	   */
#define DMACMD_ABORT		0x02	/* terminate DMA		 	   */
#define DMACMD_START		0x03	/* start DMA			 	   */

#define DMASTATUS	      	0x54	/* r	status register			   */
#define DMASTATUS_BCMPLT	0x20	/* BLAST complete			   */
#define DMASTATUS_SCSIINT	0x10	/* SCSI interrupt pending		   */
#define DMASTATUS_DONE		0x08	/* DMA transfer terminated		   */
#define DMASTATUS_ABORT		0x04	/* DMA transfer aborted			   */
#define DMASTATUS_ERROR		0x02	/* DMA transfer error			   */
#define DMASTATUS_PWDN		0x02	/* power down indicator			   */

#define DMASTC		    	0x44	/* rw	starting transfer count		   */
#define DMASPA		    	0x48	/* rw	starting physical address	   */
#define DMAWBC		    	0x4C	/* r	working byte counter		   */
#define DMAWAC		    	0x50	/* r	working address counter		   */
#define DMASMDLA	    	0x58	/* rw	starting MDL address		   */
#define DMAWMAC		    	0x5C	/* r	working MDL counter		   */

/*** SCSI phases ***/
#define PHASE_MSGIN             0x07
#define PHASE_MSGOUT            0x06
#define PHASE_RES_1             0x05
#define PHASE_RES_0             0x04
#define PHASE_STATIN            0x03
#define PHASE_CMDOUT            0x02
#define PHASE_DATAIN            0x01
#define PHASE_DATAOUT           0x00


#define AM53C974_local_declare()	unsigned long io_port
#define AM53C974_setio(instance)	io_port = instance->io_port
#define AM53C974_read_8(addr)           inb(io_port + (addr))
#define AM53C974_write_8(addr,x)        outb((x), io_port + (addr))
#define AM53C974_read_16(addr)          inw(io_port + (addr))
#define AM53C974_write_16(addr,x)       outw((x), io_port + (addr))
#define AM53C974_read_32(addr)          inl(io_port + (addr))
#define AM53C974_write_32(addr,x)       outl((x), io_port + (addr))

#define AM53C974_poll_int()             { do { statreg = AM53C974_read_8(STATREG); } \
                                             while (!(statreg & STATREG_INT)) ; \
                                          AM53C974_read_8(INSTREG) ; } /* clear int */
#define AM53C974_cfifo()		(AM53C974_read_8(CFIREG) & CFIREG_CF)

/* These are "special" values for the tag parameter passed to AM53C974_select. */
#define TAG_NEXT	-1 	/* Use next free tag */
#define TAG_NONE	-2	/* Establish I_T_L nexus instead of I_T_L_Q
				 * even on SCSI-II devices */

/************ LILO overrides *************/
typedef struct _override_t {
    int host_scsi_id;			/* SCSI id of the bus controller */
    int target_scsi_id;                 /* SCSI id of target */
    int max_rate;			/* max. transfer rate */
    int max_offset;	                /* max. sync. offset, 0 = asynchronous */
    } override_t;


#ifdef AM53C974_DEBUG
static void AM53C974_print_phase(struct Scsi_Host *instance);
static void AM53C974_print_queues(struct Scsi_Host *instance);
#endif /* AM53C974_DEBUG */
static void AM53C974_print(struct Scsi_Host *instance);
static void AM53C974_keywait(void);
static __inline__ int AM53C974_pci_detect(Scsi_Host_Template *tpnt);
static int AM53C974_init(Scsi_Host_Template *tpnt, struct pci_dev *pdev);
static void AM53C974_config_after_reset(struct Scsi_Host *instance);
static __inline__ void initialize_SCp(Scsi_Cmnd *cmd);
static __inline__ void run_main(void);
static void AM53C974_main (void);
static void AM53C974_intr(int irq, void *dev_id, struct pt_regs *regs);
static void do_AM53C974_intr(int irq, void *dev_id, struct pt_regs *regs);
static void AM53C974_intr_disconnect(struct Scsi_Host *instance); 
static int AM53C974_sync_neg(struct Scsi_Host *instance, int target, unsigned char *msg);
static __inline__ void AM53C974_set_async(struct Scsi_Host *instance, int target);
static __inline__ void AM53C974_set_sync(struct Scsi_Host *instance, int target);
static void AM53C974_information_transfer(struct Scsi_Host *instance, 
                                          unsigned char statreg, unsigned char isreg,
                                          unsigned char instreg, unsigned char cfifo,
                                          unsigned char dmastatus);
static int AM53C974_message(struct Scsi_Host *instance, Scsi_Cmnd *cmd, unsigned char msg);
static void AM53C974_select(struct Scsi_Host *instance, Scsi_Cmnd *cmd, int tag);
static void AM53C974_intr_reselect(struct Scsi_Host *instance, unsigned char statreg);
static  __inline__ void AM53C974_transfer_dma(struct Scsi_Host *instance, short dir,
                                              unsigned long length, char *data);
static void AM53C974_dma_blast(struct Scsi_Host *instance, unsigned char dmastatus, 
                               unsigned char statreg);
static void AM53C974_intr_bus_reset(struct Scsi_Host *instance);

static struct Scsi_Host *first_instance = NULL;
static Scsi_Host_Template *the_template = NULL;
static struct Scsi_Host *first_host = NULL;	/* Head of list of AMD boards */
static volatile int main_running = 0;
static int commandline_current = 0;
override_t overrides[7] = { {-1, 0, 0, 0}, };   /* LILO overrides */

struct proc_dir_entry proc_scsi_am53c974 = {
	PROC_SCSI_AM53C974, 8, "am53c974",
	S_IFDIR | S_IRUGO | S_IXUGO, 2
};

#ifdef AM53C974_DEBUG
static int deb_stop = 1;

static struct {
    unsigned char value;
    char *name;
} phases[] = {
{PHASE_DATAOUT, "DATAOUT"}, {PHASE_DATAIN, "DATAIN"}, {PHASE_CMDOUT, "CMDOUT"},
{PHASE_STATIN, "STATIN"}, {PHASE_MSGOUT, "MSGOUT"}, {PHASE_MSGIN, "MSGIN"},
{PHASE_RES_0, "RESERVED 0"}, {PHASE_RES_1, "RESERVED 1"}};

/************************************************************************** 
 * Function : void AM53C974_print_phase(struct Scsi_Host *instance)
 *
 * Purpose : print the current SCSI phase for debugging purposes
 *
 * Input : instance - which AM53C974
 **************************************************************************/
static void AM53C974_print_phase(struct Scsi_Host *instance)
{
AM53C974_local_declare();
unsigned char statreg, latched;
int           i;
AM53C974_setio(instance);

latched = (AM53C974_read_8(CNTLREG2)) & CNTLREG2_ENF;
statreg = AM53C974_read_8(STATREG);
for (i = 0; (phases[i].value != PHASE_RES_1) && 
     (phases[i].value != (statreg & STATREG_PHASE)); ++i); 
if (latched)
   printk("scsi%d : phase %s, latched at end of last command\n", instance->host_no, phases[i].name);
  else
   printk("scsi%d : phase %s, real time\n", instance->host_no, phases[i].name);
}

/**************************************************************************
 * Function : void AM53C974_print_queues(struct Scsi_Host *instance)
 *
 * Purpose : print commands in the various queues
 *
 * Inputs : instance - which AM53C974
 **************************************************************************/
static void AM53C974_print_queues(struct Scsi_Host *instance)
{
struct AM53C974_hostdata *hostdata = (struct AM53C974_hostdata *)instance->hostdata;
Scsi_Cmnd *ptr;

printk("AM53C974: coroutine is%s running.\n", main_running ? "" : "n't");
    
cli();
    
if (!hostdata->connected) {
   printk ("scsi%d: no currently connected command\n", instance->host_no); } 
  else {
   print_Scsi_Cmnd ((Scsi_Cmnd *)hostdata->connected); }
if (!hostdata->sel_cmd) {
   printk ("scsi%d: no currently arbitrating command\n", instance->host_no); } 
  else {
   print_Scsi_Cmnd ((Scsi_Cmnd *)hostdata->sel_cmd); }

printk ("scsi%d: issue_queue ", instance->host_no);
if (!hostdata->issue_queue)
   printk("empty\n");
  else {
   printk(":\n");
   for (ptr = (Scsi_Cmnd *)hostdata->issue_queue; ptr; ptr = (Scsi_Cmnd *)ptr->host_scribble) 
       print_Scsi_Cmnd (ptr); }

printk ("scsi%d: disconnected_queue ", instance->host_no);
if (!hostdata->disconnected_queue)
   printk("empty\n");
  else {
   printk(":\n");
   for (ptr = (Scsi_Cmnd *) hostdata->disconnected_queue; ptr; ptr = (Scsi_Cmnd *)ptr->host_scribble) 
       print_Scsi_Cmnd (ptr); }
    
sti();
}

#endif /* AM53C974_DEBUG */

/**************************************************************************
 * Function : void AM53C974_print(struct Scsi_Host *instance)
 *
 * Purpose : dump the chip registers for debugging purposes
 *
 * Input : instance - which AM53C974
 **************************************************************************/
static void AM53C974_print(struct Scsi_Host *instance)
{
AM53C974_local_declare();
unsigned long ctcreg, dmastc, dmaspa, dmawbc, dmawac;
unsigned char cmdreg, statreg, isreg, cfireg, cntlreg[4], dmacmd, dmastatus;
AM53C974_setio(instance);

cli();
ctcreg = AM53C974_read_8(CTCHREG) << 16;
ctcreg |= AM53C974_read_8(CTCMREG) << 8;
ctcreg |= AM53C974_read_8(CTCLREG);
cmdreg = AM53C974_read_8(CMDREG);
statreg = AM53C974_read_8(STATREG);
isreg = AM53C974_read_8(ISREG);
cfireg = AM53C974_read_8(CFIREG);
cntlreg[0] = AM53C974_read_8(CNTLREG1);
cntlreg[1] = AM53C974_read_8(CNTLREG2);
cntlreg[2] = AM53C974_read_8(CNTLREG3);
cntlreg[3] = AM53C974_read_8(CNTLREG4);
dmacmd = AM53C974_read_8(DMACMD);
dmastc = AM53C974_read_32(DMASTC);
dmaspa = AM53C974_read_32(DMASPA);
dmawbc = AM53C974_read_32(DMAWBC);
dmawac = AM53C974_read_32(DMAWAC);
dmastatus = AM53C974_read_8(DMASTATUS);
sti();

printk("AM53C974 register dump:\n");
printk("IO base: 0x%04lx; CTCREG: 0x%04lx; CMDREG: 0x%02x; STATREG: 0x%02x; ISREG: 0x%02x\n",
       io_port, ctcreg, cmdreg, statreg, isreg);
printk("CFIREG: 0x%02x; CNTLREG1-4: 0x%02x; 0x%02x; 0x%02x; 0x%02x\n",
        cfireg, cntlreg[0], cntlreg[1], cntlreg[2], cntlreg[3]);
printk("DMACMD: 0x%02x; DMASTC: 0x%04lx; DMASPA: 0x%04lx\n", dmacmd, dmastc, dmaspa);
printk("DMAWBC: 0x%04lx; DMAWAC: 0x%04lx; DMASTATUS: 0x%02x\n", dmawbc, dmawac, dmastatus);
printk("---------------------------------------------------------\n");
}

/**************************************************************************
* Function : void AM53C974_keywait(void)
*
* Purpose : wait until a key is pressed, if it was the 'r' key leave singlestep mode;
*           this function is used for debugging only
*
* Input : none
**************************************************************************/
static void AM53C974_keywait(void)
{
#ifdef AM53C974_DEBUG
int key;

if (!deb_stop) return;
#endif

cli();
while ((inb_p(0x64) & 0x01) != 0x01) ;
#ifdef AM53C974_DEBUG
key = inb(0x60);
if (key == 0x93) deb_stop = 0;  /* don't stop if 'r' was pressed */
#endif
sti();
}

/**************************************************************************
* Function : AM53C974_setup(char *str, int *ints)
*
* Purpose : LILO command line initialization of the overrides array,
* 
* Inputs : str - unused, ints - array of integer parameters with ints[0]
*	    equal to the number of ints.
*
* NOTE : this function needs to be declared as an external function
*         in init/main.c and included there in the bootsetups list
***************************************************************************/
void AM53C974_setup(char *str, int *ints)
{
if (ints[0] < 4) 
   printk("AM53C974_setup: wrong number of parameters;\n correct syntax is: AM53C974=host-scsi-id, target-scsi-id, max-rate, max-offset\n");
  else {
   if (commandline_current < (sizeof(overrides) / sizeof(override_t))) {
      if ((ints[1] < 0) || (ints[1] > 7) ||
          (ints[2] < 0) || (ints[2] > 7) ||
          (ints[1] == ints[2]) ||
          (ints[3] < (DEF_CLK / MAX_PERIOD)) || (ints[3] > (DEF_CLK / MIN_PERIOD)) ||
          (ints[4] < 0) || (ints[4] > MAX_OFFSET))
         printk("AM53C974_setup: illegal parameter\n");
        else {
         overrides[commandline_current].host_scsi_id = ints[1];
         overrides[commandline_current].target_scsi_id = ints[2];
         overrides[commandline_current].max_rate = ints[3];
         overrides[commandline_current].max_offset = ints[4];
         commandline_current++; }
      }
     else
      printk("AM53C974_setup: too many overrides\n");
   }
}

#if defined (CONFIG_PCI)
/**************************************************************************
* Function : int AM53C974_pci_detect(Scsi_Host_Template *tpnt)
*
* Purpose : detects and initializes AM53C974 SCSI chips with PCI Bios
*
* Inputs : tpnt - host template
* 
* Returns : number of host adapters detected
**************************************************************************/
static __inline__ int AM53C974_pci_detect(Scsi_Host_Template *tpnt)
{
int count = 0;        /* number of boards detected */
struct pci_dev *pdev = NULL;
unsigned short command;

while ((pdev = pci_find_device(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_SCSI, pdev))) {
    pci_read_config_word(pdev, PCI_COMMAND, &command);

    /* check whether device is I/O mapped -- should be */
    if (!(command & PCI_COMMAND_IO)) continue;

    /* PCI Spec 2.1 states that it is either the driver's or the PCI card's responsibility
       to set the PCI Master Enable Bit if needed. 
       (from Mark Stockton <marks@schooner.sys.hou.compaq.com>) */
    if (!(command & PCI_COMMAND_MASTER)) {
       command |= PCI_COMMAND_MASTER;
       printk("PCI Master Bit has not been set. Setting...\n");
       pci_write_config_word(pdev, PCI_COMMAND, command); }

    /* everything seems OK now, so initialize */
    if (AM53C974_init(tpnt, pdev)) count++ ;
    }
return (count);
}
#endif

/**************************************************************************
* Function : int AM53C974_detect(Scsi_Host_Template *tpnt)
*
* Purpose : detects and initializes AM53C974 SCSI chips
*
* Inputs : tpnt - host template
* 
* Returns : number of host adapters detected
**************************************************************************/
__initfunc(int AM53C974_detect(Scsi_Host_Template *tpnt))
{
int count = 0;        /* number of boards detected */

tpnt->proc_dir = &proc_scsi_am53c974;

#if defined (CONFIG_PCI)
if (pci_present())
   count = AM53C974_pci_detect(tpnt);
#endif
return (count);
}

/**************************************************************************
* Function : int AM53C974_init(Scsi_Host_Template *tpnt, struct pci_dev *pdev)
*
* Purpose : initializes instance and corresponding AM53/79C974 chip,
*
* Inputs : tpnt - template, pci_config - PCI configuration,
* 
* Returns : 1 on success, 0 on failure.
* 
* NOTE: If no override for the controller's SCSI id is given and AM53C974_SCSI_ID 
*       is not defined we assume that the SCSI address of this controller is correctly
*       set up by the BIOS (as reflected by contents of register CNTLREG1).
*       This is the only BIOS assistance we need.
**************************************************************************/
__initfunc(static int AM53C974_init(Scsi_Host_Template *tpnt, struct pci_dev *pdev))
{
AM53C974_local_declare();
int                      i, j;
struct Scsi_Host         *instance, *search;
struct AM53C974_hostdata *hostdata;

#ifdef AM53C974_OPTION_DEBUG_PROBE_ONLY
   printk ("AM53C974: probe only enabled, aborting initialization\n");
   return 0;
#endif

instance = scsi_register(tpnt, sizeof(struct AM53C974_hostdata));
hostdata = (struct AM53C974_hostdata *)instance->hostdata;
instance->base = NULL;
instance->io_port = pdev->base_address[0] & PCI_BASE_ADDRESS_IO_MASK;
instance->irq = pdev->irq;
instance->dma_channel = -1;
AM53C974_setio(instance);

#ifdef AM53C974_SCSI_ID
instance->this_id = AM53C974_SCSI_ID;
AM53C974_write_8(CNTLREG1, instance->this_id & CNTLREG1_SID);
#else
instance->this_id = AM53C974_read_8(CNTLREG1) & CNTLREG1_SID;
if (instance->this_id != 7) 
   printk("scsi%d: WARNING: unusual hostadapter SCSI id %d; please verify!\n", 
          instance->host_no, instance->this_id);
#endif

for (i = 0; i < sizeof(hostdata->msgout); i++) {
    hostdata->msgout[i] = NOP;
    hostdata->last_message[i] = NOP; }
for (i = 0; i < 8; i++) {
    hostdata->busy[i] = 0;
    hostdata->sync_per[i] = DEF_STP;
    hostdata->sync_off[i] = 0;
    hostdata->sync_neg[i] = 0;
    hostdata->sync_en[i] = DEFAULT_SYNC_NEGOTIATION_ENABLED;
    hostdata->max_rate[i] = DEFAULT_RATE;
    hostdata->max_offset[i] = DEFAULT_SYNC_OFFSET; }

/* overwrite defaults by LILO overrides */
for (i = 0; i < commandline_current; i++) {
    if (overrides[i].host_scsi_id == instance->this_id) {
       j = overrides[i].target_scsi_id;
       hostdata->sync_en[j] = 1;
       hostdata->max_rate[j] = overrides[i].max_rate;
       hostdata->max_offset[j] = overrides[i].max_offset; 
       }
    }

hostdata->sel_cmd = NULL;
hostdata->connected = NULL;
hostdata->issue_queue = NULL;
hostdata->disconnected_queue = NULL;
hostdata->in_reset = 0;
hostdata->aborted = 0;
hostdata->selecting = 0;
hostdata->disconnecting = 0;
hostdata->dma_busy = 0;

/* Set up an interrupt handler if we aren't already sharing an IRQ with another board */
for (search = first_host; 
     search && ( ((the_template != NULL) && (search->hostt != the_template)) || 
                 (search->irq != instance->irq) || (search == instance) );
     search = search->next);
if (!search) {
   if (request_irq(instance->irq, do_AM53C974_intr, SA_INTERRUPT, "AM53C974", NULL)) {
      printk("scsi%d: IRQ%d not free, detaching\n", instance->host_no, instance->irq);
      scsi_unregister(instance);
      return 0; } 
   }
  else {
   printk("scsi%d: using interrupt handler previously installed for scsi%d\n",
	  instance->host_no, search->host_no); }

if (!the_template) {
   the_template = instance->hostt;
   first_instance = instance; }

/* do hard reset */
AM53C974_write_8(CMDREG, CMDREG_RDEV);     /* reset device */
udelay(5);
AM53C974_write_8(CMDREG, CMDREG_NOP);
AM53C974_write_8(CNTLREG1, CNTLREG1_DISR | instance->this_id); 
AM53C974_write_8(CMDREG, CMDREG_RBUS);     /* reset SCSI bus */
udelay(10);
AM53C974_config_after_reset(instance);
udelay(500000);
return(1);
}

/*********************************************************************
* Function : AM53C974_config_after_reset(struct Scsi_Host *instance) *
*                                                                    *
* Purpose : initializes chip registers after reset                   *
*                                                                    *
* Inputs : instance - which AM53C974                                 *
*                                                                    *
* Returns : nothing                                                  *
**********************************************************************/
static void AM53C974_config_after_reset(struct Scsi_Host *instance)
{
AM53C974_local_declare(); 
AM53C974_setio(instance);

/* clear SCSI FIFO */
AM53C974_write_8(CMDREG, CMDREG_CFIFO);

/* configure device */
AM53C974_write_8(STIMREG, DEF_SCSI_TIMEOUT);
AM53C974_write_8(STPREG, DEF_STP & STPREG_STP);
AM53C974_write_8(SOFREG, (DEF_SOF_RAD<<6) | (DEF_SOF_RAA<<4));
AM53C974_write_8(CLKFREG, DEF_CLKF & CLKFREG_MASK);
AM53C974_write_8(CNTLREG1, (DEF_ETM<<7) | CNTLREG1_DISR | (DEF_PERE<<4) | instance->this_id);
AM53C974_write_8(CNTLREG2, (DEF_ENF<<6));
AM53C974_write_8(CNTLREG3, (DEF_ADIDCHK<<7) | (DEF_FASTSCSI<<4) | (DEF_FASTCLK<<3));
AM53C974_write_8(CNTLREG4, (DEF_GLITCH<<6) | (DEF_PWD<<5) | (DEF_RAE<<3) | (DEF_RADE<<2) | CNTLREG4_RES);
}

/***********************************************************************
* Function : const char *AM53C974_info(struct Scsi_Host *instance)     *
*                                                                      *
* Purpose : return device driver information                           *
*                                                                      *
* Inputs : instance - which AM53C974                                   *
*                                                                      *
* Returns : info string                                                *
************************************************************************/
const char *AM53C974_info(struct Scsi_Host *instance)
{
static char       info[100];

sprintf(info, "AM53/79C974 PCscsi driver rev. %d.%d; host I/O address: 0x%x; irq: %d\n", 
        AM53C974_DRIVER_REVISION_MAJOR, AM53C974_DRIVER_REVISION_MINOR,
        instance->io_port, instance->irq);
return (info);
}

/************************************************************************** 
* Function : int AM53C974_command (Scsi_Cmnd *SCpnt)                      *
*                                                                         *
* Purpose : the unqueued SCSI command function, replaced by the           *
*           AM53C974_queue_command function                               *
*                                                                         *
* Inputs : SCpnt - pointer to command structure                           *
*                                                                         *
* Returns :status, see hosts.h for details                                *
***************************************************************************/
int AM53C974_command(Scsi_Cmnd *SCpnt)
{
DEB(printk("AM53C974_command called\n"));
return 0;
}

/**************************************************************************
* Function : void initialize_SCp(Scsi_Cmnd *cmd)                          *
*                                                                         *
* Purpose : initialize the saved data pointers for cmd to point to the    *
*	    start of the buffer.                                          *                              
*                                                                         *
* Inputs : cmd - Scsi_Cmnd structure to have pointers reset.              *
*                                                                         *
* Returns : nothing                                                       *
**************************************************************************/
static __inline__ void initialize_SCp(Scsi_Cmnd *cmd)
{
if (cmd->use_sg) {
   cmd->SCp.buffer = (struct scatterlist *)cmd->buffer;
   cmd->SCp.buffers_residual = cmd->use_sg - 1;
   cmd->SCp.ptr = (char *)cmd->SCp.buffer->address;
   cmd->SCp.this_residual = cmd->SCp.buffer->length; }
  else {
   cmd->SCp.buffer = NULL;
   cmd->SCp.buffers_residual = 0;
   cmd->SCp.ptr = (char *)cmd->request_buffer;
   cmd->SCp.this_residual = cmd->request_bufflen; }
}

/**************************************************************************
* Function : run_main(void)                                               *
*                                                                         *
* Purpose : insure that the coroutine is running and will process our     *
* 	    request.  main_running is checked/set here (in an inline      *
*           function rather than in AM53C974_main itself to reduce the    *
*           chances of stack overflow.                                    *
*                                                                         *
*                                                                         *
* Inputs : none                                                           *
*                                                                         *
* Returns : nothing                                                       *
**************************************************************************/
static __inline__ void run_main(void)
{
cli();
if (!main_running) {
   /* main_running is cleared in AM53C974_main once it can't do 
      more work, and AM53C974_main exits with interrupts disabled. */
   main_running = 1;
   AM53C974_main();
   sti(); }
  else 
   sti();
}

/************************************************************************** 
* Function : int AM53C974_queue_command(Scsi_Cmnd *cmd, void (*done)(Scsi_Cmnd *))
*
* Purpose : writes SCSI command into AM53C974 FIFO 
*
* Inputs : cmd - SCSI command, done - function called on completion, with
*	a pointer to the command descriptor.
* 
* Returns : status, see hosts.h for details
*
* Side effects : 
*      cmd is added to the per instance issue_queue, with minor 
*	twiddling done to the host specific fields of cmd.  If the 
*	main coroutine is not running, it is restarted.
**************************************************************************/
int AM53C974_queue_command(Scsi_Cmnd *cmd, void (*done)(Scsi_Cmnd *))
{
struct Scsi_Host         *instance = cmd->host;
struct AM53C974_hostdata *hostdata = (struct AM53C974_hostdata *)instance->hostdata;
Scsi_Cmnd                *tmp;

cli();
DEB_QUEUE(printk(SEPARATOR_LINE));
DEB_QUEUE(printk("scsi%d: AM53C974_queue_command called\n", instance->host_no));
DEB_QUEUE(printk("cmd=%02x target=%02x lun=%02x bufflen=%d use_sg = %02x\n", 
	   cmd->cmnd[0], cmd->target, cmd->lun, cmd->request_bufflen, cmd->use_sg));

/* We use the host_scribble field as a pointer to the next command in a queue */
cmd->host_scribble = NULL;
cmd->scsi_done = done;
cmd->result = 0;
cmd->device->disconnect = 0;

/* Insert the cmd into the issue queue. Note that REQUEST SENSE 
 * commands are added to the head of the queue since any command will
 * clear the contingent allegiance condition that exists and the 
 * sense data is only guaranteed to be valid while the condition exists. */
if (!(hostdata->issue_queue) || (cmd->cmnd[0] == REQUEST_SENSE)) {
   LIST(cmd, hostdata->issue_queue);
   cmd->host_scribble = (unsigned char *)hostdata->issue_queue;
   hostdata->issue_queue = cmd; }
  else {
   for (tmp = (Scsi_Cmnd *)hostdata->issue_queue; tmp->host_scribble; 
	tmp = (Scsi_Cmnd *)tmp->host_scribble);
   LIST(cmd, tmp);
   tmp->host_scribble = (unsigned char *)cmd; }

DEB_QUEUE(printk("scsi%d : command added to %s of queue\n", instance->host_no,
	  (cmd->cmnd[0] == REQUEST_SENSE) ? "head" : "tail"));

/* Run the coroutine if it isn't already running. */
run_main();
return 0;
}

/**************************************************************************
 * Function : AM53C974_main (void) 
 *
 * Purpose : AM53C974_main is a coroutine that runs as long as more work can 
 *	be done on the AM53C974 host adapters in a system.  Both 
 *	AM53C974_queue_command() and AM53C974_intr() will try to start it 
 *	in case it is not running.
 * 
 * NOTE : AM53C974_main exits with interrupts *disabled*, the caller should 
 *  reenable them.  This prevents reentrancy and kernel stack overflow.
 **************************************************************************/  
static void AM53C974_main(void)
{
AM53C974_local_declare(); 
Scsi_Cmnd                *tmp, *prev;
struct Scsi_Host         *instance;
struct AM53C974_hostdata *hostdata;
int                      done;

/* We run (with interrupts disabled) until we're sure that none of 
 * the host adapters have anything that can be done, at which point 
 * we set main_running to 0 and exit. */

do {
   cli(); /* Freeze request queues */
   done = 1;
   for (instance = first_instance; instance && instance->hostt == the_template;
        instance = instance->next) {
       hostdata = (struct AM53C974_hostdata *)instance->hostdata;
       AM53C974_setio(instance);
       /* start to select target if we are not connected and not in the 
          selection process */
       if (!hostdata->connected && !hostdata->sel_cmd) {
          /* Search through the issue_queue for a command destined for a target 
             that is not busy. */
          for (tmp = (Scsi_Cmnd *)hostdata->issue_queue, prev = NULL; tmp; 
               prev = tmp, tmp = (Scsi_Cmnd *)tmp->host_scribble) {
	      /*  When we find one, remove it from the issue queue. */
	      if (!(hostdata->busy[tmp->target] & (1 << tmp->lun))) {
		 if (prev) {
		    REMOVE(prev, (Scsi_Cmnd *)(prev->host_scribble), tmp,
                           (Scsi_Cmnd *)(tmp->host_scribble));
		    prev->host_scribble = tmp->host_scribble; } 
                   else {
		    REMOVE(-1, hostdata->issue_queue, tmp, tmp->host_scribble);
		    hostdata->issue_queue = (Scsi_Cmnd *)tmp->host_scribble; }
		 tmp->host_scribble = NULL;

                 /* go into selection mode, disable reselection and wait for
                    SO interrupt which will continue with the selection process */
                 hostdata->selecting = 1;
                 hostdata->sel_cmd = tmp;
                 AM53C974_write_8(CMDREG, CMDREG_DSR); 
                 break;                 
		 } /* if target/lun is not busy */

	      } /* for */
          } /* if (!hostdata->connected) */
         else {		
          DEB(printk("main: connected; cmd = 0x%lx, sel_cmd = 0x%lx\n",
                 (long)hostdata->connected, (long)hostdata->sel_cmd));
	  }
       } /* for instance */
   } while (!done);
main_running = 0;
}

/************************************************************************
* Function : AM53C974_intr(int irq, void *dev_id, struct pt_regs *regs) *
*                                                                       *
* Purpose : interrupt handler                                           *
*                                                                       *
* Inputs : irq - interrupt line, regs - ?                               *
*                                                                       *
* Returns : nothing                                                     *
************************************************************************/
static void do_AM53C974_intr(int irq, void *dev_id, struct pt_regs *regs)
{
unsigned long flags;

spin_lock_irqsave(&io_request_lock, flags);
AM53C974_intr(irq, dev_id, regs);
spin_unlock_irqrestore(&io_request_lock, flags);
}

/************************************************************************
* Function : AM53C974_intr(int irq, void *dev_id, struct pt_regs *regs) *
*                                                                       *
* Purpose : interrupt handler                                           *
*                                                                       *
* Inputs : irq - interrupt line, regs - ?                               *
*                                                                       *
* Returns : nothing                                                     *
************************************************************************/
static void AM53C974_intr(int irq, void *dev_id, struct pt_regs *regs)
{
AM53C974_local_declare(); 
struct Scsi_Host         *instance;
struct AM53C974_hostdata *hostdata;
unsigned char            cmdreg, dmastatus, statreg, isreg, instreg, cfifo;

/* find AM53C974 hostadapter responsible for this interrupt */
for (instance = first_instance; instance; instance = instance->next)
    if ((instance->irq == irq) && (instance->hostt == the_template)) goto FOUND;
sti();
return;

/* found; now decode and process */
FOUND:
hostdata = (struct AM53C974_hostdata *)instance->hostdata;
AM53C974_setio(instance);
dmastatus = AM53C974_read_8(DMASTATUS);

DEB_INTR(printk(SEPARATOR_LINE));
DEB_INTR(printk("AM53C974 interrupt; dmastatus=0x%02x\n", dmastatus));
KEYWAIT();

/*** DMA related interrupts ***/
if (hostdata->connected && (dmastatus & (DMASTATUS_ERROR | DMASTATUS_PWDN | 
                                         DMASTATUS_ABORT))) {
   /* DMA error or POWERDOWN */
   printk("scsi%d: DMA error or powerdown; dmastatus: 0x%02x\n",
          instance->host_no, dmastatus);
#ifdef AM53C974_DEBUG
   deb_stop = 1;
#endif
   panic("scsi%d: cannot recover\n", instance->host_no); }

if (hostdata->connected && (dmastatus & DMASTATUS_DONE)) {     
   /* DMA transfer done */
   unsigned long residual;
   cli();
   if (!(AM53C974_read_8(DMACMD) & DMACMD_DIR)) {
      do {
         dmastatus = AM53C974_read_8(DMASTATUS);
         residual  = AM53C974_read_8(CTCLREG) | (AM53C974_read_8(CTCMREG) << 8) |
                    (AM53C974_read_8(CTCHREG) << 16);
         residual += AM53C974_read_8(CFIREG) & CFIREG_CF;
         } while (!(dmastatus & DMASTATUS_SCSIINT) && residual);
      residual = AM53C974_read_8(CTCLREG) | (AM53C974_read_8(CTCMREG) << 8) |
                 (AM53C974_read_8(CTCHREG) << 16);
      residual += AM53C974_read_8(CFIREG) & CFIREG_CF;
      }
     else
      residual = 0;
   hostdata->connected->SCp.ptr += hostdata->connected->SCp.this_residual - residual;
   hostdata->connected->SCp.this_residual = residual;

   AM53C974_write_8(DMACMD, DMACMD_IDLE);

   /* if service request missed before, process it now (ugly) */
   if (hostdata->dma_busy) {
      hostdata->dma_busy = 0;
      cmdreg = AM53C974_read_8(CMDREG);
      statreg = AM53C974_read_8(STATREG);
      isreg = AM53C974_read_8(ISREG);
      instreg = AM53C974_read_8(INSTREG);
      cfifo = AM53C974_cfifo();
      AM53C974_information_transfer(instance, statreg, isreg, instreg, cfifo,
                                    dmastatus); }
   sti();
   }
   
if (!(dmastatus & DMASTATUS_SCSIINT)) {
   sti();
   return; }

/*** SCSI related interrupts ***/
cmdreg = AM53C974_read_8(CMDREG);
statreg = AM53C974_read_8(STATREG);
isreg = AM53C974_read_8(ISREG);
instreg = AM53C974_read_8(INSTREG);
cfifo = AM53C974_cfifo();

DEB_INTR(printk("scsi%d: statreg: 0x%02x; isreg: 0x%02x; instreg: 0x%02x; cfifo: 0x%02x\n",
                instance->host_no, statreg, isreg, instreg, cfifo));

if (statreg & STATREG_PE) {
   /* parity error */
#ifdef AM53C974_DEBUG
   deb_stop = 1;
#endif
   printk("scsi%d : PARITY error\n", instance->host_no);
   if (hostdata->connected) hostdata->sync_off[hostdata->connected->target] = 0; /* setup asynchronous transfer */
   hostdata->aborted = 1; }

if (statreg & STATREG_IOE) {
   /* illegal operation error */
#ifdef AM53C974_DEBUG
   deb_stop = 1;
#endif
   printk("scsi%d : ILLEGAL OPERATION error\n", instance->host_no);
   printk("cmdreg:  0x%02x; dmacmd:  0x%02x; statreg: 0x%02x; \n"
          "isreg:   0x%02x; instreg: 0x%02x; cfifo:   0x%02x\n",
           cmdreg, AM53C974_read_8(DMACMD), statreg, isreg, instreg, cfifo); }
if (hostdata->in_reset && (instreg & INSTREG_SRST)) {
   /* RESET INTERRUPT */
#ifdef AM53C974_DEBUG
   deb_stop = 1;
#endif
   DEB(printk("Bus reset interrupt received\n"));
   AM53C974_intr_bus_reset(instance);
   cli();
   if (hostdata->connected) {
      hostdata->connected->result = DID_RESET << 16;
      hostdata->connected->scsi_done((Scsi_Cmnd *)hostdata->connected);
      hostdata->connected = NULL; }
     else { 
      if (hostdata->sel_cmd) {
         hostdata->sel_cmd->result = DID_RESET << 16;
         hostdata->sel_cmd->scsi_done((Scsi_Cmnd *)hostdata->sel_cmd);
         hostdata->sel_cmd = NULL; }
      }
   sti();
   if (hostdata->in_reset == 1) goto EXIT;
     else return;
   }

if (instreg & INSTREG_ICMD) {
   /* INVALID COMMAND INTERRUPT */
#ifdef AM53C974_DEBUG
   deb_stop = 1;
#endif
   printk("scsi%d: Invalid command interrupt\n", instance->host_no);
   printk("cmdreg:  0x%02x; dmacmd:  0x%02x; statreg: 0x%02x; dmastatus: 0x%02x; \n"
          "isreg:   0x%02x; instreg: 0x%02x; cfifo:   0x%02x\n",
           cmdreg, AM53C974_read_8(DMACMD), statreg, dmastatus, isreg, instreg, cfifo);
   panic("scsi%d: cannot recover\n", instance->host_no); }

if (instreg & INSTREG_DIS) {
   /* DISCONNECT INTERRUPT */
   DEB_INTR(printk("Disconnect interrupt received; "));
   cli();
   AM53C974_intr_disconnect(instance);
   sti();
   goto EXIT; }

if (instreg & INSTREG_RESEL) {
   /* RESELECTION INTERRUPT */
   DEB_INTR(printk("Reselection interrupt received\n"));
   cli();
   AM53C974_intr_reselect(instance, statreg);
   sti();
   goto EXIT; }

if (instreg & INSTREG_SO) {
   DEB_INTR(printk("Successful operation interrupt received\n"));
   if (hostdata->selecting) {
      DEB_INTR(printk("DSR completed, starting select\n"));
      cli();
      AM53C974_select(instance, (Scsi_Cmnd *)hostdata->sel_cmd,
                          (hostdata->sel_cmd->cmnd[0] == REQUEST_SENSE) ? 
                                                  TAG_NONE : TAG_NEXT);
      hostdata->selecting = 0;
      AM53C974_set_sync(instance, hostdata->sel_cmd->target);
      sti();
      return; }

   if (hostdata->sel_cmd != NULL) {
      if ( ((isreg & ISREG_IS) != ISREG_OK_NO_STOP) &&
           ((isreg & ISREG_IS) != ISREG_OK_STOP) ) {
         /* UNSUCCESSFUL SELECTION */
         DEB_INTR(printk("unsuccessful selection\n"));
         cli();
         hostdata->dma_busy = 0;
	 LIST(hostdata->sel_cmd, hostdata->issue_queue);
	 hostdata->sel_cmd->host_scribble = (unsigned char *)hostdata->issue_queue;
         hostdata->issue_queue = hostdata->sel_cmd;
         hostdata->sel_cmd = NULL;
         hostdata->selecting = 0;
         sti();
         goto EXIT; }
        else {
         /* SUCCESSFUL SELECTION */
         DEB(printk("successful selection; cmd=0x%02lx\n", (long)hostdata->sel_cmd));
         cli();
         hostdata->dma_busy = 0;
         hostdata->disconnecting = 0;
         hostdata->connected = hostdata->sel_cmd;
         hostdata->sel_cmd = NULL;
         hostdata->selecting = 0;
#ifdef SCSI2
         if (!hostdata->connected->device->tagged_queue)
#endif    
            hostdata->busy[hostdata->connected->target] |= (1 << hostdata->connected->lun);
         /* very strange -- use_sg is sometimes nonzero for request sense commands !! */
         if ((hostdata->connected->cmnd[0] == REQUEST_SENSE) && hostdata->connected->use_sg) {
            DEB(printk("scsi%d: REQUEST_SENSE command with nonzero use_sg\n", instance->host_no));
            KEYWAIT();
            hostdata->connected->use_sg = 0; }
         initialize_SCp((Scsi_Cmnd *)hostdata->connected);
         hostdata->connected->SCp.phase = PHASE_CMDOUT;
         AM53C974_information_transfer(instance, statreg, isreg, instreg, cfifo, dmastatus);
         sti();
         return; }
      }
     else {
      cli();
      AM53C974_information_transfer(instance, statreg, isreg, instreg, cfifo, dmastatus);
      sti();
      return; }
   }
    
if (instreg & INSTREG_SR) {
   DEB_INTR(printk("Service request interrupt received, "));
   if (hostdata->connected) {
      DEB_INTR(printk("calling information_transfer\n"));
      cli();
      AM53C974_information_transfer(instance, statreg, isreg, instreg, cfifo, dmastatus);
      sti(); }
     else {
      printk("scsi%d: weird: service request when no command connected\n", instance->host_no);
      AM53C974_write_8(CMDREG, CMDREG_CFIFO); }   /* clear FIFO */
   return;
   }

EXIT:
  DEB_INTR(printk("intr: starting main\n"));
  run_main();
  DEB_INTR(printk("end of intr\n"));
}

/************************************************************************** 
* Function : AM53C974_intr_disconnect(struct Scsi_Host *instance)
*
* Purpose : manage target disconnection
*
* Inputs : instance -- which AM53C974
* 
* Returns : nothing
**************************************************************************/
static void AM53C974_intr_disconnect(struct Scsi_Host *instance) 
{
AM53C974_local_declare(); 
struct AM53C974_hostdata *hostdata = (struct AM53C974_hostdata *)instance->hostdata;
Scsi_Cmnd                *cmd;
AM53C974_setio(instance);

if (hostdata->sel_cmd != NULL) {
   /* normal selection timeout, typical for nonexisting targets */
   cmd = (Scsi_Cmnd *)hostdata->sel_cmd;
   DEB_INTR(printk("bad target\n"));
   cmd->result = DID_BAD_TARGET << 16;
   goto EXIT_FINISHED; }

if (!hostdata->connected) {
   /* can happen if controller was reset, a device tried to reconnect,
      failed and disconnects now */
   AM53C974_write_8(CMDREG, CMDREG_CFIFO);
   return; }

if (hostdata->disconnecting) {
   /* target sent disconnect message, so we are prepared */
   cmd = (Scsi_Cmnd *)hostdata->connected;
   AM53C974_set_async(instance, cmd->target);
   DEB_INTR(printk("scsi%d : disc. from cmnd %d for ta %d, lun %d\n",
   	           instance->host_no, cmd->cmnd[0], cmd->target, cmd->lun));
   if (cmd->device->disconnect) {
      /* target wants to reselect later */
      DEB_INTR(printk("ok, re-enabling selection\n"));
      LIST(cmd,hostdata->disconnected_queue);
      cmd->host_scribble = (unsigned char *)hostdata->disconnected_queue;
      hostdata->disconnected_queue = cmd;
      DEB_QUEUE(printk("scsi%d : command for target %d lun %d this %d was moved from connected to"
   	               "  the disconnected_queue\n", instance->host_no, cmd->target,
                        cmd->lun, hostdata->disconnected_queue->SCp.this_residual));
      DEB_QUEUE(AM53C974_print_queues(instance));
      goto EXIT_UNFINISHED; }
     else {
      /* target does not want to reselect later, we are really finished */
#ifdef AM53C974_DEBUG
      if (cmd->cmnd[0] == REQUEST_SENSE) {
        int i;
        printk("Request sense data dump:\n");
        for (i = 0; i < cmd->request_bufflen; i++) {
             printk("%02x ", *((char *)(cmd->request_buffer) + i));
             if (i && !(i % 16)) printk("\n"); }
        printk("\n"); }
#endif
      goto EXIT_FINISHED; } /* !cmd->device->disconnect */
   } /* if (hostdata->disconnecting) */

/* no disconnect message received; unexpected disconnection */
cmd = (Scsi_Cmnd *)hostdata->connected;
if (cmd) {
#ifdef AM53C974_DEBUG
   deb_stop = 1;
#endif
   AM53C974_set_async(instance, cmd->target);
   printk("scsi%d: Unexpected disconnect; phase: %d; target: %d; this_residual: %d; buffers_residual: %d; message: %d\n",
           instance->host_no, cmd->SCp.phase, cmd->target, cmd->SCp.this_residual, cmd->SCp.buffers_residual,
           cmd->SCp.Message);
   printk("cmdreg: 0x%02x; statreg: 0x%02x; isreg: 0x%02x; cfifo: 0x%02x\n",
          AM53C974_read_8(CMDREG), AM53C974_read_8(STATREG), AM53C974_read_8(ISREG),
           AM53C974_read_8(CFIREG) & CFIREG_CF);

    if ((hostdata->last_message[0] == EXTENDED_MESSAGE) && 
        (hostdata->last_message[2] == EXTENDED_SDTR)) {
        /* sync. negotiation was aborted, setup asynchronous transfer with target */
        hostdata->sync_off[cmd->target] = 0; }
   if (hostdata->aborted || hostdata->msgout[0] == ABORT)
      cmd->result = DID_ABORT << 16;
     else
      cmd->result = DID_ERROR << 16;
   goto EXIT_FINISHED; }

EXIT_FINISHED:
hostdata->aborted = 0;
hostdata->msgout[0] = NOP;
hostdata->sel_cmd = NULL;
hostdata->connected = NULL;
hostdata->selecting = 0;
hostdata->disconnecting = 0;
hostdata->dma_busy = 0;
hostdata->busy[cmd->target] &= ~(1 << cmd->lun);
AM53C974_write_8(CMDREG, CMDREG_CFIFO);
DEB(printk("disconnect; issue_queue: 0x%lx, disconnected_queue: 0x%lx\n", 
       (long)hostdata->issue_queue, (long)hostdata->disconnected_queue));
cmd->scsi_done(cmd);

if (!hostdata->selecting) {
   AM53C974_set_async(instance, cmd->target); 
   AM53C974_write_8(CMDREG, CMDREG_ESR); } /* allow reselect */
return;

EXIT_UNFINISHED:
hostdata->msgout[0] = NOP;
hostdata->sel_cmd = NULL;
hostdata->connected = NULL;
hostdata->aborted = 0;
hostdata->selecting = 0;
hostdata->disconnecting = 0;
hostdata->dma_busy = 0;
DEB(printk("disconnect; issue_queue: 0x%lx, disconnected_queue: 0x%lx\n", 
       (long)hostdata->issue_queue, (long)hostdata->disconnected_queue));
if (!hostdata->selecting) {
   AM53C974_set_async(instance, cmd->target); 
   AM53C974_write_8(CMDREG, CMDREG_ESR); } /* allow reselect */
return;
}

/************************************************************************** 
* Function : int AM53C974_sync_neg(struct Scsi_Host *instance, int target, unsigned char *msg)
*
* Purpose : setup message string for sync. negotiation
*
* Inputs : instance -- which AM53C974
*          target -- which SCSI target to deal with
*          msg -- input message string
* 
* Returns : 0 if parameters accepted or 1 if not accepted
*
* Side effects: hostdata is changed
*
* Note: we assume here that fastclk is enabled
**************************************************************************/
static int AM53C974_sync_neg(struct Scsi_Host *instance, int target, unsigned char *msg) 
{
AM53C974_local_declare(); 
struct AM53C974_hostdata *hostdata = (struct AM53C974_hostdata *)instance->hostdata;
int                      period, offset, i, rate, rate_rem;
AM53C974_setio(instance);

period = (DEF_CLK * msg[3] * 8 + 1000) / 2000;
if (period < MIN_PERIOD) {
    period = MIN_PERIOD;
    hostdata->msgout[3] = period / 4; }
   else
    if (period > MAX_PERIOD) {
       period = MAX_PERIOD;
       hostdata->msgout[3] = period / 4; }
      else
       hostdata->msgout[3] = msg[3];
offset = msg[4]; 
if (offset > MAX_OFFSET) offset = MAX_OFFSET;
hostdata->msgout[4] = offset;
hostdata->sync_per[target] = period;
hostdata->sync_off[target] = offset;
for (i = 0; i < 3; i++) hostdata->msgout[i] = msg[i];
if ((hostdata->msgout[3] != msg[3]) || (msg[4] != offset)) return(1);

rate = DEF_CLK / period;
rate_rem = 10 * (DEF_CLK - period * rate) / period;

if (offset)
   printk("\ntarget %d: rate=%d.%d Mhz, synchronous, sync offset=%d bytes\n",
          target, rate, rate_rem, offset);
  else
   printk("\ntarget %d: rate=%d.%d Mhz, asynchronous\n", target, rate, rate_rem);

return(0);
}

/************************************************************************** 
* Function : AM53C974_set_async(struct Scsi_Host *instance, int target)
*
* Purpose : put controller into async. mode
*
* Inputs : instance -- which AM53C974
*          target -- which SCSI target to deal with
* 
* Returns : nothing
**************************************************************************/
static __inline__ void AM53C974_set_async(struct Scsi_Host *instance, int target)
{
AM53C974_local_declare(); 
struct AM53C974_hostdata *hostdata = (struct AM53C974_hostdata *)instance->hostdata;
AM53C974_setio(instance);

AM53C974_write_8(STPREG, hostdata->sync_per[target]);
AM53C974_write_8(SOFREG, (DEF_SOF_RAD<<6) | (DEF_SOF_RAA<<4));
}

/************************************************************************** 
* Function : AM53C974_set_sync(struct Scsi_Host *instance, int target)
*
* Purpose : put controller into sync. mode
*
* Inputs : instance -- which AM53C974
*          target -- which SCSI target to deal with
* 
* Returns : nothing
**************************************************************************/
static __inline__ void AM53C974_set_sync(struct Scsi_Host *instance, int target)
{
AM53C974_local_declare(); 
struct AM53C974_hostdata *hostdata = (struct AM53C974_hostdata *)instance->hostdata;
AM53C974_setio(instance);

AM53C974_write_8(STPREG, hostdata->sync_per[target]);
AM53C974_write_8(SOFREG, (SOFREG_SO & hostdata->sync_off[target]) | 
                (DEF_SOF_RAD<<6) | (DEF_SOF_RAA<<4));
}

/***********************************************************************
* Function : AM53C974_information_transfer(struct Scsi_Host *instance, *
*                          unsigned char statreg, unsigned char isreg, *
*                         unsigned char instreg, unsigned char cfifo,  *
*                         unsigned char dmastatus)                     *
*                                                                      *
* Purpose : handle phase changes                                       *
*                                                                      *
* Inputs : instance - which AM53C974                                   *
*          statreg - status register                                     *
*          isreg - internal state register                             *
*          instreg - interrupt status register                         *
*          cfifo - number of bytes in FIFO                             *
*          dmastatus - dma status register                             *
*                                                                      *
* Returns : nothing                                                    *
************************************************************************/
static void AM53C974_information_transfer(struct Scsi_Host *instance, 
                                          unsigned char statreg, unsigned char isreg,
                                          unsigned char instreg, unsigned char cfifo,
                                          unsigned char dmastatus)
{
AM53C974_local_declare(); 
struct AM53C974_hostdata *hostdata = (struct AM53C974_hostdata *)instance->hostdata;
Scsi_Cmnd                *cmd = (Scsi_Cmnd *)hostdata->connected;
int                      ret, i, len, residual=-1;
AM53C974_setio(instance);

DEB_INFO(printk(SEPARATOR_LINE));
switch (statreg & STATREG_PHASE) {	/* scsi phase */
  case PHASE_DATAOUT:
    DEB_INFO(printk("Dataout phase; cmd=0x%lx, sel_cmd=0x%lx, this_residual=%d, buffers_residual=%d\n",
                    (long)hostdata->connected, (long)hostdata->sel_cmd, cmd->SCp.this_residual, cmd->SCp.buffers_residual));
    cmd->SCp.phase = PHASE_DATAOUT;
    goto PHASE_DATA_IO;

  case PHASE_DATAIN:
    DEB_INFO(printk("Datain phase; cmd=0x%lx, sel_cmd=0x%lx, this_residual=%d, buffers_residual=%d\n",
                     (long)hostdata->connected, (long)hostdata->sel_cmd, cmd->SCp.this_residual, cmd->SCp.buffers_residual));
    cmd->SCp.phase = PHASE_DATAIN;
    PHASE_DATA_IO:
    if (hostdata->aborted) {
       AM53C974_write_8(DMACMD, DMACMD_IDLE);
       AM53C974_write_8(CMDREG, CMDREG_CFIFO);
       AM53C974_write_8(CMDREG, CMDREG_SATN);
       return; }
    if ((!cmd->SCp.this_residual) && cmd->SCp.buffers_residual) {
       cmd->SCp.buffer++;
       cmd->SCp.buffers_residual--;
       cmd->SCp.ptr = (unsigned char *)cmd->SCp.buffer->address;
       cmd->SCp.this_residual = cmd->SCp.buffer->length; }
    if (cmd->SCp.this_residual) {
       if (!(AM53C974_read_8(DMACMD) & DMACMD_START)) {
          hostdata->dma_busy = 0;
          AM53C974_transfer_dma(instance, statreg & STATREG_IO,
                                (unsigned long)cmd->SCp.this_residual,
                                cmd->SCp.ptr); }
         else
          hostdata->dma_busy = 1;
       }
    return;

  case PHASE_MSGIN:
    DEB_INFO(printk("Message-In phase; cmd=0x%lx, sel_cmd=0x%lx\n",
                    (long)hostdata->connected, (long)hostdata->sel_cmd));
    AM53C974_set_async(instance, cmd->target);
    if (cmd->SCp.phase == PHASE_DATAIN)
       AM53C974_dma_blast(instance, dmastatus, statreg);
    if ((cmd->SCp.phase == PHASE_DATAOUT) && (AM53C974_read_8(DMACMD) & DMACMD_START)) {
       AM53C974_write_8(DMACMD, DMACMD_IDLE);
       residual = cfifo + (AM53C974_read_8(CTCLREG) | (AM53C974_read_8(CTCMREG) << 8) |
                          (AM53C974_read_8(CTCHREG) << 16));
       cmd->SCp.ptr += cmd->SCp.this_residual - residual;
       cmd->SCp.this_residual = residual;
       if (cfifo) { AM53C974_write_8(CMDREG, CMDREG_CFIFO); cfifo = 0; }
       }
    if (cmd->SCp.phase == PHASE_STATIN) {
       while ((AM53C974_read_8(CFIREG) & CFIREG_CF) < 2) ;
       cmd->SCp.Status = AM53C974_read_8(FFREG);
       cmd->SCp.Message = AM53C974_read_8(FFREG); 
       DEB_INFO(printk("Message-In phase; status=0x%02x, message=0x%02x\n",
                       cmd->SCp.Status, cmd->SCp.Message));
       ret = AM53C974_message(instance, cmd, cmd->SCp.Message); }
      else {
       if (!cfifo) {
          AM53C974_write_8(CMDREG, CMDREG_IT); 
          AM53C974_poll_int();
          cmd->SCp.Message = AM53C974_read_8(FFREG);
          }
       ret = AM53C974_message(instance, cmd, cmd->SCp.Message);
       }
    cmd->SCp.phase = PHASE_MSGIN;
    AM53C974_set_sync(instance, cmd->target);
    break;
  case PHASE_MSGOUT:
    DEB_INFO(printk("Message-Out phase; cfifo=%d; msgout[0]=0x%02x\n",
                    AM53C974_read_8(CFIREG) & CFIREG_CF, hostdata->msgout[0]));
    AM53C974_write_8(DMACMD, DMACMD_IDLE);
    AM53C974_set_async(instance, cmd->target);
    for (i = 0; i < sizeof(hostdata->last_message); i++) 
        hostdata->last_message[i] = hostdata->msgout[i];
    if ((hostdata->msgout[0] == 0) || INSIDE(hostdata->msgout[0], 0x02, 0x1F) || 
        INSIDE(hostdata->msgout[0], 0x80, 0xFF)) 
       len = 1;
      else {
       if (hostdata->msgout[0] == EXTENDED_MESSAGE) {
#ifdef AM53C974_DEBUG_INFO
          printk("Extended message dump:\n");
          for (i = 0; i < hostdata->msgout[1] + 2; i++) {
              printk("%02x ", hostdata->msgout[i]);
              if (i && !(i % 16)) printk("\n"); }
          printk("\n");
#endif
          len = hostdata->msgout[1] + 2; }
         else
          len = 2;
       }
    for (i = 0; i < len; i++) AM53C974_write_8(FFREG, hostdata->msgout[i]);
    AM53C974_write_8(CMDREG, CMDREG_IT);
    cmd->SCp.phase = PHASE_MSGOUT;
    hostdata->msgout[0] = NOP;
    AM53C974_set_sync(instance, cmd->target);
    break;

  case PHASE_CMDOUT:
    DEB_INFO(printk("Command-Out phase\n"));
    AM53C974_set_async(instance, cmd->target);
    for (i = 0; i < cmd->cmd_len; i++) AM53C974_write_8(FFREG, cmd->cmnd[i]);
    AM53C974_write_8(CMDREG, CMDREG_IT);
    cmd->SCp.phase = PHASE_CMDOUT;
    AM53C974_set_sync(instance, cmd->target);
    break;

  case PHASE_STATIN:
    DEB_INFO(printk("Status phase\n"));
    if (cmd->SCp.phase == PHASE_DATAIN)
       AM53C974_dma_blast(instance, dmastatus, statreg);
    AM53C974_set_async(instance, cmd->target);
    if (cmd->SCp.phase == PHASE_DATAOUT) {
       unsigned long residual;

       if (AM53C974_read_8(DMACMD) & DMACMD_START) {
          AM53C974_write_8(DMACMD, DMACMD_IDLE);
          residual = cfifo + (AM53C974_read_8(CTCLREG) | (AM53C974_read_8(CTCMREG) << 8) |
                              (AM53C974_read_8(CTCHREG) << 16));
          cmd->SCp.ptr += cmd->SCp.this_residual - residual;
          cmd->SCp.this_residual = residual; }
       if (cfifo) { AM53C974_write_8(CMDREG, CMDREG_CFIFO); cfifo = 0; }
       }
    cmd->SCp.phase = PHASE_STATIN;
    AM53C974_write_8(CMDREG, CMDREG_ICCS);  /* command complete */
    break;

  case PHASE_RES_0:
  case PHASE_RES_1:
#ifdef AM53C974_DEBUG
   deb_stop = 1;
#endif
    DEB_INFO(printk("Reserved phase\n"));
    break;
  }
KEYWAIT();
}

/******************************************************************************
* Function : int AM53C974_message(struct Scsi_Host *instance, Scsi_Cmnd *cmd,
*                                 unsigned char msg)                
*
* Purpose : handle SCSI messages
*
* Inputs : instance -- which AM53C974
*          cmd -- SCSI command the message belongs to
*          msg -- message id byte
* 
* Returns : 1 on success, 0 on failure.
**************************************************************************/
static int AM53C974_message(struct Scsi_Host *instance, Scsi_Cmnd *cmd,
                            unsigned char msg)
{
AM53C974_local_declare(); 
static unsigned char     extended_msg[10];
unsigned char            statreg;
int                      len, ret = 0;
unsigned char            *p;
#ifdef AM53C974_DEBUG_MSG
int                      j;
#endif
struct AM53C974_hostdata *hostdata = (struct AM53C974_hostdata *)instance->hostdata;
AM53C974_setio(instance);

DEB_MSG(printk(SEPARATOR_LINE));

/* Linking lets us reduce the time required to get the 
 * next command out to the device, hopefully this will
 * mean we don't waste another revolution due to the delays
 * required by ARBITRATION and another SELECTION.
 * In the current implementation proposal, low level drivers
 * merely have to start the next command, pointed to by 
 * next_link, done() is called as with unlinked commands. */
switch (msg) {
#ifdef LINKED
  case LINKED_CMD_COMPLETE:
  case LINKED_FLG_CMD_COMPLETE:
    /* Accept message by releasing ACK */
    DEB_LINKED(printk("scsi%d : target %d lun %d linked command complete.\n",
			instance->host_no, cmd->target, cmd->lun));
    /* Sanity check : A linked command should only terminate with
     * one of these messages if there are more linked commands available. */
    if (!cmd->next_link) {
       printk("scsi%d : target %d lun %d linked command complete, no next_link\n"
	       instance->host_no, cmd->target, cmd->lun);
       hostdata->aborted = 1;
       AM53C974_write_8(CMDREG, CMDREG_SATN);
       AM53C974_write_8(CMDREG, CMDREG_MA);
       break; }
    if (hostdata->aborted) {
       DEB_ABORT(printk("ATN set for cmnd %d upon reception of LINKED_CMD_COMPLETE or"
                        "LINKED_FLG_CMD_COMPLETE message\n", cmd->cmnd[0]));
       AM53C974_write_8(CMDREG, CMDREG_SATN); }
    AM53C974_write_8(CMDREG, CMDREG_MA);

    initialize_SCp(cmd->next_link);
    /* The next command is still part of this process */
    cmd->next_link->tag = cmd->tag;
    cmd->result = cmd->SCp.Status | (cmd->SCp.Message << 8); 
    DEB_LINKED(printk("scsi%d : target %d lun %d linked request done, calling scsi_done().\n",
		      instance->host_no, cmd->target, cmd->lun));
    cmd->scsi_done(cmd);
    cmd = hostdata->connected;
    break;

#endif /* def LINKED */

  case ABORT:
  case COMMAND_COMPLETE: 
    DEB_MSG(printk("scsi%d: command complete message received; cmd %d for target %d, lun %d\n",
	           instance->host_no, cmd->cmnd[0], cmd->target, cmd->lun));
    hostdata->disconnecting = 1;
    cmd->device->disconnect = 0;

    /* I'm not sure what the correct thing to do here is : 
     * 
     * If the command that just executed is NOT a request 
     * sense, the obvious thing to do is to set the result
     * code to the values of the stored parameters.
     * If it was a REQUEST SENSE command, we need some way 
     * to differentiate between the failure code of the original
     * and the failure code of the REQUEST sense - the obvious
     * case is success, where we fall through and leave the result
     * code unchanged.
     * 
     * The non-obvious place is where the REQUEST SENSE failed  */
    if (cmd->cmnd[0] != REQUEST_SENSE) 
       cmd->result = cmd->SCp.Status | (cmd->SCp.Message << 8); 
      else if (cmd->SCp.Status != GOOD)
       cmd->result = (cmd->result & 0x00ffff) | (DID_ERROR << 16);		    
    if (hostdata->aborted) {
       AM53C974_write_8(CMDREG, CMDREG_SATN);
       AM53C974_write_8(CMDREG, CMDREG_MA);
       DEB_ABORT(printk("ATN set for cmnd %d upon reception of ABORT or"
                        "COMMAND_COMPLETE message\n", cmd->cmnd[0]));
       break; }
    if ((cmd->cmnd[0] != REQUEST_SENSE) && (cmd->SCp.Status == CHECK_CONDITION)) {
       DEB_MSG(printk("scsi%d : performing request sense\n", instance->host_no));
       cmd->cmnd[0] = REQUEST_SENSE;
       cmd->cmnd[1] &= 0xe0;
       cmd->cmnd[2] = 0;
       cmd->cmnd[3] = 0;
       cmd->cmnd[4] = sizeof(cmd->sense_buffer);
       cmd->cmnd[5] = 0;
       cmd->SCp.buffer = NULL;
       cmd->SCp.buffers_residual = 0;
       cmd->SCp.ptr = (char *)cmd->sense_buffer;
       cmd->SCp.this_residual = sizeof(cmd->sense_buffer);
       LIST(cmd,hostdata->issue_queue);
       cmd->host_scribble = (unsigned char *)hostdata->issue_queue;
       hostdata->issue_queue = (Scsi_Cmnd *)cmd;
       DEB_MSG(printk("scsi%d : REQUEST SENSE added to head of issue queue\n",instance->host_no));
       }

    /* Accept message by clearing ACK */
    AM53C974_write_8(CMDREG, CMDREG_MA);
    break;
		
  case MESSAGE_REJECT:
    DEB_MSG(printk("scsi%d: reject message received; cmd %d for target %d, lun %d\n",
	           instance->host_no, cmd->cmnd[0], cmd->target, cmd->lun));
    switch (hostdata->last_message[0]) {
      case EXTENDED_MESSAGE:
        if (hostdata->last_message[2] == EXTENDED_SDTR) {
           /* sync. negotiation was rejected, setup asynchronous transfer with target */
           printk("\ntarget %d: rate=%d Mhz, asynchronous (sync. negotiation rejected)\n",
                  cmd->target,  DEF_CLK / DEF_STP);
           hostdata->sync_off[cmd->target] = 0;
           hostdata->sync_per[cmd->target] = DEF_STP; }
        break;
      case HEAD_OF_QUEUE_TAG:
      case ORDERED_QUEUE_TAG:
      case SIMPLE_QUEUE_TAG:
        cmd->device->tagged_queue = 0;
        hostdata->busy[cmd->target] |= (1 << cmd->lun);
        break;
      default:
        break;
      }
    if (hostdata->aborted) AM53C974_write_8(CMDREG, CMDREG_SATN);
    AM53C974_write_8(CMDREG, CMDREG_MA);
    break;
	
  case DISCONNECT:
    DEB_MSG(printk("scsi%d: disconnect message received; cmd %d for target %d, lun %d\n",
	           instance->host_no, cmd->cmnd[0], cmd->target, cmd->lun));
    cmd->device->disconnect = 1;
    hostdata->disconnecting = 1;
    AM53C974_write_8(CMDREG, CMDREG_MA); /* Accept message by clearing ACK */
    break;
		
  case SAVE_POINTERS:
  case RESTORE_POINTERS:
    DEB_MSG(printk("scsi%d: save/restore pointers message received; cmd %d for target %d, lun %d\n",
	           instance->host_no, cmd->cmnd[0], cmd->target, cmd->lun));
    /* The SCSI data pointer is *IMPLICITLY* saved on a disconnect
     * operation, in violation of the SCSI spec so we can safely 
     * ignore SAVE/RESTORE pointers calls.
     *
     * Unfortunately, some disks violate the SCSI spec and 
     * don't issue the required SAVE_POINTERS message before
     * disconnecting, and we have to break spec to remain 
     * compatible. */
    if (hostdata->aborted) {
       DEB_ABORT(printk("ATN set for cmnd %d upon reception of SAVE/REST. POINTERS message\n",
                         cmd->cmnd[0]));
       AM53C974_write_8(CMDREG, CMDREG_SATN); }
    AM53C974_write_8(CMDREG, CMDREG_MA);
    break;

  case EXTENDED_MESSAGE:
    DEB_MSG(printk("scsi%d: extended message received; cmd %d for target %d, lun %d\n",
	           instance->host_no, cmd->cmnd[0], cmd->target, cmd->lun));
   /* Extended messages are sent in the following format :
    * Byte 	
    * 0		  EXTENDED_MESSAGE == 1
    * 1		  length (includes one byte for code, doesn't include first two bytes)
    * 2 	  code
    * 3..length+1 arguments
    */
   /* BEWARE!! THIS CODE IS EXTREMELY UGLY */
    extended_msg[0] = EXTENDED_MESSAGE;
    AM53C974_read_8(INSTREG) ; /* clear int */
    AM53C974_write_8(CMDREG, CMDREG_MA);  /* ack. msg byte, then wait for SO */  
    AM53C974_poll_int();
    /* get length */
    AM53C974_write_8(CMDREG, CMDREG_IT); 
    AM53C974_poll_int();
    AM53C974_write_8(CMDREG, CMDREG_MA);  /* ack. msg byte, then wait for SO */   
    AM53C974_poll_int();
    extended_msg[1] = len = AM53C974_read_8(FFREG); /* get length */
    p = extended_msg+2;
    /* read the remaining (len) bytes */
    while (len) {
      AM53C974_write_8(CMDREG, CMDREG_IT); 
      AM53C974_poll_int();
      if (len > 1) {
         AM53C974_write_8(CMDREG, CMDREG_MA);  /* ack. msg byte, then wait for SO */   
         AM53C974_poll_int(); }
      *p = AM53C974_read_8(FFREG);
      p++; len--; }

#ifdef AM53C974_DEBUG_MSG
    printk("scsi%d: received extended message: ", instance->host_no);
    for (j = 0; j < extended_msg[1] + 2; j++) {
        printk("0x%02x ", extended_msg[j]);
        if (j && !(j % 16)) printk("\n"); }
    printk("\n");
#endif

    /* check message */
    if (extended_msg[2] == EXTENDED_SDTR)
       ret = AM53C974_sync_neg(instance, cmd->target, extended_msg);
    if (ret || hostdata->aborted) AM53C974_write_8(CMDREG, CMDREG_SATN);

    AM53C974_write_8(CMDREG, CMDREG_MA); 
    break;

  default:
    printk("scsi%d: unknown message 0x%02x received\n",instance->host_no, msg);
#ifdef AM53C974_DEBUG
   deb_stop = 1;
#endif
    /* reject message */
    hostdata->msgout[0] = MESSAGE_REJECT; 
    AM53C974_write_8(CMDREG, CMDREG_SATN);
    AM53C974_write_8(CMDREG, CMDREG_MA);
    return(0);
    break;

  } /* switch (msg) */
KEYWAIT();
return(1);
}

/************************************************************************** 
* Function : AM53C974_select(struct Scsi_Host *instance, Scsi_Cmnd *cmd, int tag)
*
* Purpose : try to establish nexus for the command;
*           start sync negotiation via start stop and transfer the command in 
*           cmdout phase in case of an inquiry or req. sense command with no 
*           sync. neg. performed yet
*
* Inputs : instance -- which AM53C974
*          cmd -- command which requires the selection
*          tag -- tagged queueing
* 
* Returns : nothing
*        
* Note: this function initializes the selection process, which is continued 
*       in the interrupt handler
**************************************************************************/
static void AM53C974_select(struct Scsi_Host *instance, Scsi_Cmnd *cmd, int tag)
{
AM53C974_local_declare(); 
struct AM53C974_hostdata *hostdata = (struct AM53C974_hostdata *)instance->hostdata;
unsigned char            cfifo, tmp[3];
unsigned int             i, len, cmd_size = COMMAND_SIZE(cmd->cmnd[0]);
AM53C974_setio(instance);

cfifo = AM53C974_cfifo();
if (cfifo) {
   printk("scsi%d: select error; %d residual bytes in FIFO\n", instance->host_no, cfifo);
   AM53C974_write_8(CMDREG, CMDREG_CFIFO); /* clear FIFO */
   }                  

#ifdef AM53C974_PROHIBIT_DISCONNECT
tmp[0] = IDENTIFY(0, cmd->lun);
#else
tmp[0] = IDENTIFY(1, cmd->lun);
#endif

#ifdef SCSI2
if (cmd->device->tagged_queue && (tag != TAG_NONE)) {
   tmp[1] = SIMPLE_QUEUE_TAG;
   if (tag == TAG_NEXT) {
      /* 0 is TAG_NONE, used to imply no tag for this command */
      if (cmd->device->current_tag == 0) cmd->device->current_tag = 1;
      cmd->tag = cmd->device->current_tag;
      cmd->device->current_tag++; }
     else  
      cmd->tag = (unsigned char)tag;
   tmp[2] = cmd->tag;
   hostdata->last_message[0] = SIMPLE_QUEUE_TAG;
   len = 3;
   AM53C974_write_8(FFREG, tmp[0]);
   AM53C974_write_8(FFREG, tmp[1]);
   AM53C974_write_8(FFREG, tmp[2]);
   }
  else
#endif /* def SCSI2 */
   {
   len = 1;
   AM53C974_write_8(FFREG, tmp[0]);
   cmd->tag = 0; }

/* in case of an inquiry or req. sense command with no sync. neg performed yet, we start
   sync negotiation via start stops and transfer the command in cmdout phase */
if (((cmd->cmnd[0] == INQUIRY) || (cmd->cmnd[0] == REQUEST_SENSE)) &&
    !(hostdata->sync_neg[cmd->target]) && hostdata->sync_en[cmd->target]) {
   hostdata->sync_neg[cmd->target] = 1;
   hostdata->msgout[0] = EXTENDED_MESSAGE;
   hostdata->msgout[1] = 3;
   hostdata->msgout[2] = EXTENDED_SDTR;
   hostdata->msgout[3] = 250 / (int)hostdata->max_rate[cmd->target];
   hostdata->msgout[4] = hostdata->max_offset[cmd->target];
   len += 5; }

AM53C974_write_8(SDIDREG, SDIREG_MASK & cmd->target);       /* setup dest. id  */
AM53C974_write_8(STIMREG, DEF_SCSI_TIMEOUT);                /* setup timeout reg */
switch (len) {
  case 1:
   for (i = 0; i < cmd_size; i++) AM53C974_write_8(FFREG, cmd->cmnd[i]);
   AM53C974_write_8(CMDREG, CMDREG_SAS);                    /* select with ATN, 1 msg byte */
   hostdata->msgout[0] = NOP;
   break;
  case 3:
   for (i = 0; i < cmd_size; i++) AM53C974_write_8(FFREG, cmd->cmnd[i]);
   AM53C974_write_8(CMDREG, CMDREG_SA3S);                   /* select with ATN, 3 msg bytes */
   hostdata->msgout[0] = NOP;
   break;
  default:
   AM53C974_write_8(CMDREG, CMDREG_SASS);   /* select with ATN, stop steps; continue in message out phase */
   break;
  }
}

/************************************************************************** 
* Function : AM53C974_intr_select(struct Scsi_Host *instance, unsigned char statreg)
*
* Purpose : handle reselection 
*
* Inputs : instance -- which AM53C974
*          statreg -- status register
* 
* Returns : nothing
*
* side effects: manipulates hostdata
**************************************************************************/
static void AM53C974_intr_reselect(struct Scsi_Host *instance, unsigned char statreg)
{
AM53C974_local_declare(); 
struct AM53C974_hostdata *hostdata = (struct AM53C974_hostdata *)instance->hostdata;
unsigned char            cfifo, msg[3], lun, t, target = 0;
#ifdef SCSI2
 unsigned                char tag;
#endif
Scsi_Cmnd                *tmp = NULL, *prev;
AM53C974_setio(instance);

cfifo = AM53C974_cfifo();

if (hostdata->selecting) {
   /* caught reselect interrupt in selection process;
      put selecting command back into the issue queue and continue with the
      reselecting command */
   DEB_RESEL(printk("AM53C974_intr_reselect: in selection process\n"));
   LIST(hostdata->sel_cmd, hostdata->issue_queue);
   hostdata->sel_cmd->host_scribble = (unsigned char *)hostdata->issue_queue;
   hostdata->issue_queue = hostdata->sel_cmd;
   hostdata->sel_cmd = NULL;
   hostdata->selecting = 0; }

/* 2 bytes must be in the FIFO now */
if (cfifo != 2) {
   printk("scsi %d: error: %d bytes in fifo, 2 expected\n", instance->host_no, cfifo);
   hostdata->aborted = 1;
   goto EXIT_ABORT; }

/* determine target which reselected */
t = AM53C974_read_8(FFREG);
if (!(t & (1 << instance->this_id))) {
   printk("scsi %d: error: invalid host id\n", instance->host_no);
   hostdata->aborted = 1;
   goto EXIT_ABORT; }
t ^= (1 << instance->this_id);
target = 0; while (t != 1) { t >>= 1; target++; }
DEB_RESEL(printk("scsi %d: reselect; target: %d\n", instance->host_no, target));
      
if (hostdata->aborted) goto EXIT_ABORT;

if ((statreg & STATREG_PHASE) != PHASE_MSGIN) {
   printk("scsi %d: error: upon reselection interrupt not in MSGIN\n", instance->host_no);
   hostdata->aborted = 1;
   goto EXIT_ABORT; }

msg[0] = AM53C974_read_8(FFREG);
if (!msg[0] & 0x80) {
   printk("scsi%d: error: expecting IDENTIFY message, got ", instance->host_no);
   print_msg(msg);
   hostdata->aborted = 1;
   goto EXIT_ABORT; }

lun = (msg[0] & 0x07);

/* We need to add code for SCSI-II to track which devices have
 * I_T_L_Q nexuses established, and which have simple I_T_L
 * nexuses so we can chose to do additional data transfer. */
#ifdef SCSI2
#error "SCSI-II tagged queueing is not supported yet"
#endif

/* Find the command corresponding to the I_T_L or I_T_L_Q  nexus we 
 * just reestablished, and remove it from the disconnected queue. */
for (tmp = (Scsi_Cmnd *)hostdata->disconnected_queue, prev = NULL; 
     tmp; prev = tmp, tmp = (Scsi_Cmnd *)tmp->host_scribble) 
    if ((target == tmp->target) && (lun == tmp->lun) 
#ifdef SCSI2
         && (tag == tmp->tag) 
#endif
       ) {
       if (prev) {
	  REMOVE(prev, (Scsi_Cmnd *)(prev->host_scribble), tmp,
                 (Scsi_Cmnd *)(tmp->host_scribble));
	  prev->host_scribble = tmp->host_scribble; } 
         else {
	  REMOVE(-1, hostdata->disconnected_queue, tmp, tmp->host_scribble);
	  hostdata->disconnected_queue = (Scsi_Cmnd *)tmp->host_scribble; }
       tmp->host_scribble = NULL;
       hostdata->connected = tmp;
       break; }

if (!tmp) {
#ifdef SCSI2
   printk("scsi%d: warning : target %d lun %d tag %d not in disconnect_queue.\n",
         instance->host_no, target, lun, tag);
#else
   printk("scsi%d: warning : target %d lun %d not in disconnect_queue.\n",
         instance->host_no, target, lun);
#endif
   /* Since we have an established nexus that we can't do anything with, we must abort it. */
   hostdata->aborted = 1;
   DEB(AM53C974_keywait());
   goto EXIT_ABORT; }
  else
   goto EXIT_OK;

EXIT_ABORT: 
AM53C974_write_8(CMDREG, CMDREG_SATN);
AM53C974_write_8(CMDREG, CMDREG_MA);
return;

EXIT_OK:
DEB_RESEL(printk("scsi%d: nexus established, target = %d, lun = %d, tag = %d\n",
	  instance->host_no, target, tmp->lun, tmp->tag));
AM53C974_set_sync(instance, target);
AM53C974_write_8(SDIDREG, SDIREG_MASK & target);       /* setup dest. id  */
AM53C974_write_8(CMDREG, CMDREG_MA);
hostdata->dma_busy = 0;
hostdata->connected->SCp.phase = PHASE_CMDOUT;
}

/************************************************************************** 
* Function : AM53C974_transfer_dma(struct Scsi_Host *instance, short dir,
*                                  unsigned long length, char *data)
*
* Purpose : setup DMA transfer
*
* Inputs : instance -- which AM53C974
*          dir -- direction flag, 0: write to device, read from memory; 
*                                 1: read from device, write to memory
*          length -- number of bytes to transfer to from buffer
*          data -- pointer to data buffer
* 
* Returns : nothing
**************************************************************************/
static __inline__ void AM53C974_transfer_dma(struct Scsi_Host *instance, short dir,
                                             unsigned long length, char *data)
{
AM53C974_local_declare();
AM53C974_setio(instance);

AM53C974_write_8(CMDREG, CMDREG_NOP);
AM53C974_write_8(DMACMD, (dir << 7) | DMACMD_INTE_D);  /* idle command */
AM53C974_write_8(STCLREG, (unsigned char)(length & 0xff));
AM53C974_write_8(STCMREG, (unsigned char)((length & 0xff00) >> 8));
AM53C974_write_8(STCHREG, (unsigned char)((length & 0xff0000) >> 16));
AM53C974_write_32(DMASTC, length & 0xffffff);
AM53C974_write_32(DMASPA, virt_to_bus(data));
AM53C974_write_8(CMDREG, CMDREG_IT | CMDREG_DMA);
AM53C974_write_8(DMACMD, (dir << 7) | DMACMD_INTE_D | DMACMD_START);
}

/************************************************************************** 
* Function : AM53C974_dma_blast(struct Scsi_Host *instance, unsigned char dmastatus,
*                               unsigned char statreg)
*
* Purpose : cleanup DMA transfer
*
* Inputs : instance -- which AM53C974
*          dmastatus -- dma status register
*          statreg -- status register
* 
* Returns : nothing
**************************************************************************/
static void AM53C974_dma_blast(struct Scsi_Host *instance, unsigned char dmastatus,
                               unsigned char statreg)
{
AM53C974_local_declare();
struct AM53C974_hostdata *hostdata = (struct AM53C974_hostdata *)instance->hostdata;
unsigned long            ctcreg;
int                      dir = statreg & STATREG_IO;
int                      cfifo, pio, i = 0;
AM53C974_setio(instance);

do {
   cfifo = AM53C974_cfifo();
   i++;
   } while (cfifo && (i < 50000));
pio = (i == 50000) ? 1: 0;

if (statreg & STATREG_CTZ) { AM53C974_write_8(DMACMD, DMACMD_IDLE); return; }

if (dmastatus & DMASTATUS_DONE) { AM53C974_write_8(DMACMD, DMACMD_IDLE); return; }

AM53C974_write_8(DMACMD, ((dir << 7) & DMACMD_DIR) | DMACMD_BLAST);
while(!(AM53C974_read_8(DMASTATUS) & DMASTATUS_BCMPLT)) ;
AM53C974_write_8(DMACMD, DMACMD_IDLE);

if (pio) {
   /* transfer residual bytes via PIO */
   unsigned char *wac = (unsigned char *)AM53C974_read_32(DMAWAC);
   printk("pio mode, residual=%d\n", AM53C974_read_8(CFIREG) & CFIREG_CF);
   while (AM53C974_read_8(CFIREG) & CFIREG_CF) *(wac++) = AM53C974_read_8(FFREG);
   }

ctcreg = AM53C974_read_8(CTCLREG) | (AM53C974_read_8(CTCMREG) << 8) |
         (AM53C974_read_8(CTCHREG) << 16);

hostdata->connected->SCp.ptr += hostdata->connected->SCp.this_residual - ctcreg;
hostdata->connected->SCp.this_residual = ctcreg;
}

/************************************************************************** 
* Function : AM53C974_intr_bus_reset(struct Scsi_Host *instance)
*
* Purpose : handle bus reset interrupt
*
* Inputs : instance -- which AM53C974
* 
* Returns : nothing
**************************************************************************/
static void AM53C974_intr_bus_reset(struct Scsi_Host *instance)
{
AM53C974_local_declare();
unsigned char cntlreg1;
AM53C974_setio(instance);

AM53C974_write_8(CMDREG, CMDREG_CFIFO);
AM53C974_write_8(CMDREG, CMDREG_NOP);

cntlreg1 = AM53C974_read_8(CNTLREG1);
AM53C974_write_8(CNTLREG1, cntlreg1 | CNTLREG1_DISR);
}

/**************************************************************************
* Function : int AM53C974_abort(Scsi_Cmnd *cmd)
*
* Purpose : abort a command
*
* Inputs : cmd - the Scsi_Cmnd to abort, code - code to set the 
* 	host byte of the result field to, if zero DID_ABORTED is 
*	used.
*
* Returns : 0 - success, -1 on failure.
 **************************************************************************/
int AM53C974_abort(Scsi_Cmnd *cmd)
{
AM53C974_local_declare();
struct Scsi_Host         *instance = cmd->host;
struct AM53C974_hostdata *hostdata = (struct AM53C974_hostdata *)instance->hostdata;
Scsi_Cmnd                *tmp, **prev;

#ifdef AM53C974_DEBUG
   deb_stop = 1;
#endif
cli();
AM53C974_setio(instance);

DEB_ABORT(printk(SEPARATOR_LINE));
DEB_ABORT(printk("scsi%d : AM53C974_abort called -- trouble starts!!\n", instance->host_no));
DEB_ABORT(AM53C974_print(instance));
DEB_ABORT(AM53C974_keywait());

/* Case 1 : If the command is the currently executing command, 
            we'll set the aborted flag and return control so that the
            information transfer routine can exit cleanly. */
if ((hostdata->connected == cmd) || (hostdata->sel_cmd == cmd)) {
   DEB_ABORT(printk("scsi%d: aborting connected command\n", instance->host_no));
   hostdata->aborted = 1;
   hostdata->msgout[0] = ABORT;
   sti();
   return(SCSI_ABORT_PENDING); }

/* Case 2 : If the command hasn't been issued yet,
            we simply remove it from the issue queue. */
for (prev = (Scsi_Cmnd **)&(hostdata->issue_queue), 
     tmp = (Scsi_Cmnd *)hostdata->issue_queue; tmp; 
     prev = (Scsi_Cmnd **)&(tmp->host_scribble),
     tmp = (Scsi_Cmnd *)tmp->host_scribble) {
    if (cmd == tmp) {
       DEB_ABORT(printk("scsi%d : abort removed command from issue queue.\n", instance->host_no));
       REMOVE(5, *prev, tmp, tmp->host_scribble);
       (*prev) = (Scsi_Cmnd *)tmp->host_scribble;
       tmp->host_scribble = NULL;
       tmp->result = DID_ABORT << 16;
       sti();
       tmp->done(tmp);
       return(SCSI_ABORT_SUCCESS); }
#ifdef AM53C974_DEBUG_ABORT
      else {
       if (prev == (Scsi_Cmnd **)tmp) 
          printk("scsi%d : LOOP\n", instance->host_no); 
       }
#endif
    }
 
/* Case 3 : If any commands are connected, we're going to fail the abort
 *	    and let the high level SCSI driver retry at a later time or 
 *	    issue a reset.
 *
 *	    Timeouts, and therefore aborted commands, will be highly unlikely
 *          and handling them cleanly in this situation would make the common
 *	    case of noresets less efficient, and would pollute our code.  So,
 *	    we fail. */
if (hostdata->connected || hostdata->sel_cmd) {
   DEB_ABORT(printk("scsi%d : abort failed, other command connected.\n", instance->host_no));
   sti();
   return(SCSI_ABORT_NOT_RUNNING); }

/* Case 4: If the command is currently disconnected from the bus, and 
 * 	   there are no connected commands, we reconnect the I_T_L or 
 *	   I_T_L_Q nexus associated with it, go into message out, and send 
 *         an abort message. */
for (tmp = (Scsi_Cmnd *)hostdata->disconnected_queue; tmp; 
     tmp = (Scsi_Cmnd *)tmp->host_scribble) {
     if (cmd == tmp) {
        DEB_ABORT(printk("scsi%d: aborting disconnected command\n", instance->host_no));
        hostdata->aborted = 1;
        hostdata->msgout[0] = ABORT;
        hostdata->selecting = 1;
        hostdata->sel_cmd = tmp;
        AM53C974_write_8(CMDREG, CMDREG_DSR);
        sti();
        return(SCSI_ABORT_PENDING); }
     }

/* Case 5 : If we reached this point, the command was not found in any of 
 *	    the queues.
 *
 * We probably reached this point because of an unlikely race condition
 * between the command completing successfully and the abortion code,
 * so we won't panic, but we will notify the user in case something really
 * broke. */
DEB_ABORT(printk("scsi%d : abort failed, command not found.\n", instance->host_no));
sti();
return(SCSI_ABORT_NOT_RUNNING);
}

/************************************************************************** 
* Function : int AM53C974_reset(Scsi_Cmnd *cmd)
*
* Purpose : reset the SCSI controller and bus
*
* Inputs : cmd -- which command within the command block was responsible for the reset
* 
* Returns : status (SCSI_ABORT_SUCCESS)
* 
* FIXME(eric) the reset_flags are ignored.
**************************************************************************/
int AM53C974_reset(Scsi_Cmnd *cmd, unsigned int reset_flags)
{
    AM53C974_local_declare();
    int                      i;
    struct Scsi_Host         *instance = cmd->host;
    struct AM53C974_hostdata *hostdata = (struct AM53C974_hostdata *)instance->hostdata;
    AM53C974_setio(instance);
    
    cli();
    DEB(printk("AM53C974_reset called; "));
    
    printk("AM53C974_reset called\n");
    AM53C974_print(instance);
    AM53C974_keywait();
    
/* do hard reset */
    AM53C974_write_8(CMDREG, CMDREG_RDEV);
    AM53C974_write_8(CMDREG, CMDREG_NOP);
    hostdata->msgout[0] = NOP;
    for (i = 0; i < 8; i++) {
	hostdata->busy[i] = 0;
	hostdata->sync_per[i] = DEF_STP;
	hostdata->sync_off[i] = 0;
	hostdata->sync_neg[i] = 0; }
    hostdata->last_message[0] = NOP;
    hostdata->sel_cmd = NULL;
    hostdata->connected = NULL;
    hostdata->issue_queue = NULL;
    hostdata->disconnected_queue = NULL;
    hostdata->in_reset = 0;
    hostdata->aborted = 0;
    hostdata->selecting = 0;
    hostdata->disconnecting = 0;
    hostdata->dma_busy = 0;
    
/* reset bus */
    AM53C974_write_8(CNTLREG1, CNTLREG1_DISR | instance->this_id); /* disable interrupt upon SCSI RESET */
    AM53C974_write_8(CMDREG, CMDREG_RBUS);     /* reset SCSI bus */
    udelay(40);
    AM53C974_config_after_reset(instance);
    
    sti();
    cmd->result = DID_RESET << 16;
    cmd->scsi_done(cmd);
    return SCSI_ABORT_SUCCESS;
}


/*
 * AM53C974_release()
 *
 * Release resources allocated for a single AM53C974 adapter.
 */
int
AM53C974_release(struct Scsi_Host *shp)
{
	free_irq(shp->irq, NULL);
	scsi_unregister(shp);
	return 0;
}


#ifdef MODULE
static Scsi_Host_Template driver_template = AM53C974;

#include "scsi_module.c"
#endif
