[SCSI] sym2: Remove code to handle DMA_BIDIRECTION requests

[linux-2.6/verdex.git] / drivers / scsi / sym53c8xx_2 / sym_hipd.c

/*
 * Device driver for the SYMBIOS/LSILOGIC 53C8XX and 53C1010 family 
 * of PCI-SCSI IO processors.
 *
 * Copyright (C) 1999-2001  Gerard Roudier <groudier@free.fr>
 * Copyright (c) 2003-2005  Matthew Wilcox <matthew@wil.cx>
 *
 * This driver is derived from the Linux sym53c8xx driver.
 * Copyright (C) 1998-2000  Gerard Roudier
 *
 * The sym53c8xx driver is derived from the ncr53c8xx driver that had been 
 * a port of the FreeBSD ncr driver to Linux-1.2.13.
 *
 * The original ncr driver has been written for 386bsd and FreeBSD by
 *         Wolfgang Stanglmeier        <wolf@cologne.de>
 *         Stefan Esser                <se@mi.Uni-Koeln.de>
 * Copyright (C) 1994  Wolfgang Stanglmeier
 *
 * Other major contributions:
 *
 * NVRAM detection and reading.
 * Copyright (C) 1997 Richard Waltham <dormouse@farsrobt.demon.co.uk>
 *
 *-----------------------------------------------------------------------------
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <linux/slab.h>
#include <asm/param.h>          /* for timeouts in units of HZ */

#include "sym_glue.h"
#include "sym_nvram.h"

#if 0
#define SYM_DEBUG_GENERIC_SUPPORT
#endif

/*
 *  Needed function prototypes.
 */
static void sym_int_ma (struct sym_hcb *np);
static void sym_int_sir (struct sym_hcb *np);
static struct sym_ccb *sym_alloc_ccb(struct sym_hcb *np);
static struct sym_ccb *sym_ccb_from_dsa(struct sym_hcb *np, u32 dsa);
static void sym_alloc_lcb_tags (struct sym_hcb *np, u_char tn, u_char ln);
static void sym_complete_error (struct sym_hcb *np, struct sym_ccb *cp);
static void sym_complete_ok (struct sym_hcb *np, struct sym_ccb *cp);
static int sym_compute_residual(struct sym_hcb *np, struct sym_ccb *cp);

/*
 *  Print a buffer in hexadecimal format with a ".\n" at end.
 */
static void sym_printl_hex(u_char *p, int n)
{
        while (n-- > 0)
                printf (" %x", *p++);
        printf (".\n");
}

/*
 *  Print out the content of a SCSI message.
 */
static int sym_show_msg (u_char * msg)
{
        u_char i;
        printf ("%x",*msg);
        if (*msg==M_EXTENDED) {
                for (i=1;i<8;i++) {
                        if (i-1>msg[1]) break;
                        printf ("-%x",msg[i]);
                }
                return (i+1);
        } else if ((*msg & 0xf0) == 0x20) {
                printf ("-%x",msg[1]);
                return (2);
        }
        return (1);
}

static void sym_print_msg(struct sym_ccb *cp, char *label, u_char *msg)
{
        sym_print_addr(cp->cmd, "%s: ", label);

        sym_show_msg(msg);
        printf(".\n");
}

static void sym_print_nego_msg(struct sym_hcb *np, int target, char *label, u_char *msg)
{
        struct sym_tcb *tp = &np->target[target];
        dev_info(&tp->starget->dev, "%s: ", label);

        sym_show_msg(msg);
        printf(".\n");
}

/*
 *  Print something that tells about extended errors.
 */
void sym_print_xerr(struct scsi_cmnd *cmd, int x_status)
{
        if (x_status & XE_PARITY_ERR) {
                sym_print_addr(cmd, "unrecovered SCSI parity error.\n");
        }
        if (x_status & XE_EXTRA_DATA) {
                sym_print_addr(cmd, "extraneous data discarded.\n");
        }
        if (x_status & XE_BAD_PHASE) {
                sym_print_addr(cmd, "illegal scsi phase (4/5).\n");
        }
        if (x_status & XE_SODL_UNRUN) {
                sym_print_addr(cmd, "ODD transfer in DATA OUT phase.\n");
        }
        if (x_status & XE_SWIDE_OVRUN) {
                sym_print_addr(cmd, "ODD transfer in DATA IN phase.\n");
        }
}

/*
 *  Return a string for SCSI BUS mode.
 */
static char *sym_scsi_bus_mode(int mode)
{
        switch(mode) {
        case SMODE_HVD: return "HVD";
        case SMODE_SE:  return "SE";
        case SMODE_LVD: return "LVD";
        }
        return "??";
}

/*
 *  Soft reset the chip.
 *
 *  Raising SRST when the chip is running may cause 
 *  problems on dual function chips (see below).
 *  On the other hand, LVD devices need some delay 
 *  to settle and report actual BUS mode in STEST4.
 */
static void sym_chip_reset (struct sym_hcb *np)
{
        OUTB(np, nc_istat, SRST);
        INB(np, nc_mbox1);
        udelay(10);
        OUTB(np, nc_istat, 0);
        INB(np, nc_mbox1);
        udelay(2000);   /* For BUS MODE to settle */
}

/*
 *  Really soft reset the chip.:)
 *
 *  Some 896 and 876 chip revisions may hang-up if we set 
 *  the SRST (soft reset) bit at the wrong time when SCRIPTS 
 *  are running.
 *  So, we need to abort the current operation prior to 
 *  soft resetting the chip.
 */
static void sym_soft_reset (struct sym_hcb *np)
{
        u_char istat = 0;
        int i;

        if (!(np->features & FE_ISTAT1) || !(INB(np, nc_istat1) & SCRUN))
                goto do_chip_reset;

        OUTB(np, nc_istat, CABRT);
        for (i = 100000 ; i ; --i) {
                istat = INB(np, nc_istat);
                if (istat & SIP) {
                        INW(np, nc_sist);
                }
                else if (istat & DIP) {
                        if (INB(np, nc_dstat) & ABRT)
                                break;
                }
                udelay(5);
        }
        OUTB(np, nc_istat, 0);
        if (!i)
                printf("%s: unable to abort current chip operation, "
                       "ISTAT=0x%02x.\n", sym_name(np), istat);
do_chip_reset:
        sym_chip_reset(np);
}

/*
 *  Start reset process.
 *
 *  The interrupt handler will reinitialize the chip.
 */
static void sym_start_reset(struct sym_hcb *np)
{
        sym_reset_scsi_bus(np, 1);
}
 
int sym_reset_scsi_bus(struct sym_hcb *np, int enab_int)
{
        u32 term;
        int retv = 0;

        sym_soft_reset(np);     /* Soft reset the chip */
        if (enab_int)
                OUTW(np, nc_sien, RST);
        /*
         *  Enable Tolerant, reset IRQD if present and 
         *  properly set IRQ mode, prior to resetting the bus.
         */
        OUTB(np, nc_stest3, TE);
        OUTB(np, nc_dcntl, (np->rv_dcntl & IRQM));
        OUTB(np, nc_scntl1, CRST);
        INB(np, nc_mbox1);
        udelay(200);

        if (!SYM_SETUP_SCSI_BUS_CHECK)
                goto out;
        /*
         *  Check for no terminators or SCSI bus shorts to ground.
         *  Read SCSI data bus, data parity bits and control signals.
         *  We are expecting RESET to be TRUE and other signals to be 
         *  FALSE.
         */
        term =  INB(np, nc_sstat0);
        term =  ((term & 2) << 7) + ((term & 1) << 17); /* rst sdp0 */
        term |= ((INB(np, nc_sstat2) & 0x01) << 26) |   /* sdp1     */
                ((INW(np, nc_sbdl) & 0xff)   << 9)  |   /* d7-0     */
                ((INW(np, nc_sbdl) & 0xff00) << 10) |   /* d15-8    */
                INB(np, nc_sbcl);       /* req ack bsy sel atn msg cd io    */

        if (!np->maxwide)
                term &= 0x3ffff;

        if (term != (2<<7)) {
                printf("%s: suspicious SCSI data while resetting the BUS.\n",
                        sym_name(np));
                printf("%s: %sdp0,d7-0,rst,req,ack,bsy,sel,atn,msg,c/d,i/o = "
                        "0x%lx, expecting 0x%lx\n",
                        sym_name(np),
                        (np->features & FE_WIDE) ? "dp1,d15-8," : "",
                        (u_long)term, (u_long)(2<<7));
                if (SYM_SETUP_SCSI_BUS_CHECK == 1)
                        retv = 1;
        }
out:
        OUTB(np, nc_scntl1, 0);
        return retv;
}

/*
 *  Select SCSI clock frequency
 */
static void sym_selectclock(struct sym_hcb *np, u_char scntl3)
{
        /*
         *  If multiplier not present or not selected, leave here.
         */
        if (np->multiplier <= 1) {
                OUTB(np, nc_scntl3, scntl3);
                return;
        }

        if (sym_verbose >= 2)
                printf ("%s: enabling clock multiplier\n", sym_name(np));

        OUTB(np, nc_stest1, DBLEN);        /* Enable clock multiplier */
        /*
         *  Wait for the LCKFRQ bit to be set if supported by the chip.
         *  Otherwise wait 50 micro-seconds (at least).
         */
        if (np->features & FE_LCKFRQ) {
                int i = 20;
                while (!(INB(np, nc_stest4) & LCKFRQ) && --i > 0)
                        udelay(20);
                if (!i)
                        printf("%s: the chip cannot lock the frequency\n",
                                sym_name(np));
        } else {
                INB(np, nc_mbox1);
                udelay(50+10);
        }
        OUTB(np, nc_stest3, HSC);               /* Halt the scsi clock  */
        OUTB(np, nc_scntl3, scntl3);
        OUTB(np, nc_stest1, (DBLEN|DBLSEL));/* Select clock multiplier  */
        OUTB(np, nc_stest3, 0x00);              /* Restart scsi clock   */
}


/*
 *  Determine the chip's clock frequency.
 *
 *  This is essential for the negotiation of the synchronous 
 *  transfer rate.
 *
 *  Note: we have to return the correct value.
 *  THERE IS NO SAFE DEFAULT VALUE.
 *
 *  Most NCR/SYMBIOS boards are delivered with a 40 Mhz clock.
 *  53C860 and 53C875 rev. 1 support fast20 transfers but 
 *  do not have a clock doubler and so are provided with a 
 *  80 MHz clock. All other fast20 boards incorporate a doubler 
 *  and so should be delivered with a 40 MHz clock.
 *  The recent fast40 chips (895/896/895A/1010) use a 40 Mhz base 
 *  clock and provide a clock quadrupler (160 Mhz).
 */

/*
 *  calculate SCSI clock frequency (in KHz)
 */
static unsigned getfreq (struct sym_hcb *np, int gen)
{
        unsigned int ms = 0;
        unsigned int f;

        /*
         * Measure GEN timer delay in order 
         * to calculate SCSI clock frequency
         *
         * This code will never execute too
         * many loop iterations (if DELAY is 
         * reasonably correct). It could get
         * too low a delay (too high a freq.)
         * if the CPU is slow executing the 
         * loop for some reason (an NMI, for
         * example). For this reason we will
         * if multiple measurements are to be 
         * performed trust the higher delay 
         * (lower frequency returned).
         */
        OUTW(np, nc_sien, 0);   /* mask all scsi interrupts */
        INW(np, nc_sist);       /* clear pending scsi interrupt */
        OUTB(np, nc_dien, 0);   /* mask all dma interrupts */
        INW(np, nc_sist);       /* another one, just to be sure :) */
        /*
         * The C1010-33 core does not report GEN in SIST,
         * if this interrupt is masked in SIEN.
         * I don't know yet if the C1010-66 behaves the same way.
         */
        if (np->features & FE_C10) {
                OUTW(np, nc_sien, GEN);
                OUTB(np, nc_istat1, SIRQD);
        }
        OUTB(np, nc_scntl3, 4);    /* set pre-scaler to divide by 3 */
        OUTB(np, nc_stime1, 0);    /* disable general purpose timer */
        OUTB(np, nc_stime1, gen);  /* set to nominal delay of 1<<gen * 125us */
        while (!(INW(np, nc_sist) & GEN) && ms++ < 100000)
                udelay(1000/4);    /* count in 1/4 of ms */
        OUTB(np, nc_stime1, 0);    /* disable general purpose timer */
        /*
         * Undo C1010-33 specific settings.
         */
        if (np->features & FE_C10) {
                OUTW(np, nc_sien, 0);
                OUTB(np, nc_istat1, 0);
        }
        /*
         * set prescaler to divide by whatever 0 means
         * 0 ought to choose divide by 2, but appears
         * to set divide by 3.5 mode in my 53c810 ...
         */
        OUTB(np, nc_scntl3, 0);

        /*
         * adjust for prescaler, and convert into KHz 
         */
        f = ms ? ((1 << gen) * (4340*4)) / ms : 0;

        /*
         * The C1010-33 result is biased by a factor 
         * of 2/3 compared to earlier chips.
         */
        if (np->features & FE_C10)
                f = (f * 2) / 3;

        if (sym_verbose >= 2)
                printf ("%s: Delay (GEN=%d): %u msec, %u KHz\n",
                        sym_name(np), gen, ms/4, f);

        return f;
}

static unsigned sym_getfreq (struct sym_hcb *np)
{
        u_int f1, f2;
        int gen = 8;

        getfreq (np, gen);      /* throw away first result */
        f1 = getfreq (np, gen);
        f2 = getfreq (np, gen);
        if (f1 > f2) f1 = f2;           /* trust lower result   */
        return f1;
}

/*
 *  Get/probe chip SCSI clock frequency
 */
static void sym_getclock (struct sym_hcb *np, int mult)
{
        unsigned char scntl3 = np->sv_scntl3;
        unsigned char stest1 = np->sv_stest1;
        unsigned f1;

        np->multiplier = 1;
        f1 = 40000;
        /*
         *  True with 875/895/896/895A with clock multiplier selected
         */
        if (mult > 1 && (stest1 & (DBLEN+DBLSEL)) == DBLEN+DBLSEL) {
                if (sym_verbose >= 2)
                        printf ("%s: clock multiplier found\n", sym_name(np));
                np->multiplier = mult;
        }

        /*
         *  If multiplier not found or scntl3 not 7,5,3,
         *  reset chip and get frequency from general purpose timer.
         *  Otherwise trust scntl3 BIOS setting.
         */
        if (np->multiplier != mult || (scntl3 & 7) < 3 || !(scntl3 & 1)) {
                OUTB(np, nc_stest1, 0);         /* make sure doubler is OFF */
                f1 = sym_getfreq (np);

                if (sym_verbose)
                        printf ("%s: chip clock is %uKHz\n", sym_name(np), f1);

                if      (f1 <   45000)          f1 =  40000;
                else if (f1 <   55000)          f1 =  50000;
                else                            f1 =  80000;

                if (f1 < 80000 && mult > 1) {
                        if (sym_verbose >= 2)
                                printf ("%s: clock multiplier assumed\n",
                                        sym_name(np));
                        np->multiplier  = mult;
                }
        } else {
                if      ((scntl3 & 7) == 3)     f1 =  40000;
                else if ((scntl3 & 7) == 5)     f1 =  80000;
                else                            f1 = 160000;

                f1 /= np->multiplier;
        }

        /*
         *  Compute controller synchronous parameters.
         */
        f1              *= np->multiplier;
        np->clock_khz   = f1;
}

/*
 *  Get/probe PCI clock frequency
 */
static int sym_getpciclock (struct sym_hcb *np)
{
        int f = 0;

        /*
         *  For now, we only need to know about the actual 
         *  PCI BUS clock frequency for C1010-66 chips.
         */
#if 1
        if (np->features & FE_66MHZ) {
#else
        if (1) {
#endif
                OUTB(np, nc_stest1, SCLK); /* Use the PCI clock as SCSI clock */
                f = sym_getfreq(np);
                OUTB(np, nc_stest1, 0);
        }
        np->pciclk_khz = f;

        return f;
}

/*
 *  SYMBIOS chip clock divisor table.
 *
 *  Divisors are multiplied by 10,000,000 in order to make 
 *  calculations more simple.
 */
#define _5M 5000000
static u32 div_10M[] = {2*_5M, 3*_5M, 4*_5M, 6*_5M, 8*_5M, 12*_5M, 16*_5M};

/*
 *  Get clock factor and sync divisor for a given 
 *  synchronous factor period.
 */
static int 
sym_getsync(struct sym_hcb *np, u_char dt, u_char sfac, u_char *divp, u_char *fakp)
{
        u32     clk = np->clock_khz;    /* SCSI clock frequency in kHz  */
        int     div = np->clock_divn;   /* Number of divisors supported */
        u32     fak;                    /* Sync factor in sxfer         */
        u32     per;                    /* Period in tenths of ns       */
        u32     kpc;                    /* (per * clk)                  */
        int     ret;

        /*
         *  Compute the synchronous period in tenths of nano-seconds
         */
        if (dt && sfac <= 9)    per = 125;
        else if (sfac <= 10)    per = 250;
        else if (sfac == 11)    per = 303;
        else if (sfac == 12)    per = 500;
        else                    per = 40 * sfac;
        ret = per;

        kpc = per * clk;
        if (dt)
                kpc <<= 1;

        /*
         *  For earliest C10 revision 0, we cannot use extra 
         *  clocks for the setting of the SCSI clocking.
         *  Note that this limits the lowest sync data transfer 
         *  to 5 Mega-transfers per second and may result in
         *  using higher clock divisors.
         */
#if 1
        if ((np->features & (FE_C10|FE_U3EN)) == FE_C10) {
                /*
                 *  Look for the lowest clock divisor that allows an 
                 *  output speed not faster than the period.
                 */
                while (div > 0) {
                        --div;
                        if (kpc > (div_10M[div] << 2)) {
                                ++div;
                                break;
                        }
                }
                fak = 0;                        /* No extra clocks */
                if (div == np->clock_divn) {    /* Are we too fast ? */
                        ret = -1;
                }
                *divp = div;
                *fakp = fak;
                return ret;
        }
#endif

        /*
         *  Look for the greatest clock divisor that allows an 
         *  input speed faster than the period.
         */
        while (div-- > 0)
                if (kpc >= (div_10M[div] << 2)) break;

        /*
         *  Calculate the lowest clock factor that allows an output 
         *  speed not faster than the period, and the max output speed.
         *  If fak >= 1 we will set both XCLKH_ST and XCLKH_DT.
         *  If fak >= 2 we will also set XCLKS_ST and XCLKS_DT.
         */
        if (dt) {
                fak = (kpc - 1) / (div_10M[div] << 1) + 1 - 2;
                /* ret = ((2+fak)*div_10M[div])/np->clock_khz; */
        } else {
                fak = (kpc - 1) / div_10M[div] + 1 - 4;
                /* ret = ((4+fak)*div_10M[div])/np->clock_khz; */
        }

        /*
         *  Check against our hardware limits, or bugs :).
         */
        if (fak > 2) {
                fak = 2;
                ret = -1;
        }

        /*
         *  Compute and return sync parameters.
         */
        *divp = div;
        *fakp = fak;

        return ret;
}

/*
 *  SYMBIOS chips allow burst lengths of 2, 4, 8, 16, 32, 64,
 *  128 transfers. All chips support at least 16 transfers 
 *  bursts. The 825A, 875 and 895 chips support bursts of up 
 *  to 128 transfers and the 895A and 896 support bursts of up
 *  to 64 transfers. All other chips support up to 16 
 *  transfers bursts.
 *
 *  For PCI 32 bit data transfers each transfer is a DWORD.
 *  It is a QUADWORD (8 bytes) for PCI 64 bit data transfers.
 *
 *  We use log base 2 (burst length) as internal code, with 
 *  value 0 meaning "burst disabled".
 */

/*
 *  Burst length from burst code.
 */
#define burst_length(bc) (!(bc))? 0 : 1 << (bc)

/*
 *  Burst code from io register bits.
 */
#define burst_code(dmode, ctest4, ctest5) \
        (ctest4) & 0x80? 0 : (((dmode) & 0xc0) >> 6) + ((ctest5) & 0x04) + 1

/*
 *  Set initial io register bits from burst code.
 */
static __inline void sym_init_burst(struct sym_hcb *np, u_char bc)
{
        np->rv_ctest4   &= ~0x80;
        np->rv_dmode    &= ~(0x3 << 6);
        np->rv_ctest5   &= ~0x4;

        if (!bc) {
                np->rv_ctest4   |= 0x80;
        }
        else {
                --bc;
                np->rv_dmode    |= ((bc & 0x3) << 6);
                np->rv_ctest5   |= (bc & 0x4);
        }
}


/*
 * Print out the list of targets that have some flag disabled by user.
 */
static void sym_print_targets_flag(struct sym_hcb *np, int mask, char *msg)
{
        int cnt;
        int i;

        for (cnt = 0, i = 0 ; i < SYM_CONF_MAX_TARGET ; i++) {
                if (i == np->myaddr)
                        continue;
                if (np->target[i].usrflags & mask) {
                        if (!cnt++)
                                printf("%s: %s disabled for targets",
                                        sym_name(np), msg);
                        printf(" %d", i);
                }
        }
        if (cnt)
                printf(".\n");
}

/*
 *  Save initial settings of some IO registers.
 *  Assumed to have been set by BIOS.
 *  We cannot reset the chip prior to reading the 
 *  IO registers, since informations will be lost.
 *  Since the SCRIPTS processor may be running, this 
 *  is not safe on paper, but it seems to work quite 
 *  well. :)
 */
static void sym_save_initial_setting (struct sym_hcb *np)
{
        np->sv_scntl0   = INB(np, nc_scntl0) & 0x0a;
        np->sv_scntl3   = INB(np, nc_scntl3) & 0x07;
        np->sv_dmode    = INB(np, nc_dmode)  & 0xce;
        np->sv_dcntl    = INB(np, nc_dcntl)  & 0xa8;
        np->sv_ctest3   = INB(np, nc_ctest3) & 0x01;
        np->sv_ctest4   = INB(np, nc_ctest4) & 0x80;
        np->sv_gpcntl   = INB(np, nc_gpcntl);
        np->sv_stest1   = INB(np, nc_stest1);
        np->sv_stest2   = INB(np, nc_stest2) & 0x20;
        np->sv_stest4   = INB(np, nc_stest4);
        if (np->features & FE_C10) {    /* Always large DMA fifo + ultra3 */
                np->sv_scntl4   = INB(np, nc_scntl4);
                np->sv_ctest5   = INB(np, nc_ctest5) & 0x04;
        }
        else
                np->sv_ctest5   = INB(np, nc_ctest5) & 0x24;
}

/*
 *  Prepare io register values used by sym_start_up() 
 *  according to selected and supported features.
 */
static int sym_prepare_setting(struct Scsi_Host *shost, struct sym_hcb *np, struct sym_nvram *nvram)
{
        u_char  burst_max;
        u32     period;
        int i;

        /*
         *  Wide ?
         */
        np->maxwide     = (np->features & FE_WIDE)? 1 : 0;

        /*
         *  Guess the frequency of the chip's clock.
         */
        if      (np->features & (FE_ULTRA3 | FE_ULTRA2))
                np->clock_khz = 160000;
        else if (np->features & FE_ULTRA)
                np->clock_khz = 80000;
        else
                np->clock_khz = 40000;

        /*
         *  Get the clock multiplier factor.
         */
        if      (np->features & FE_QUAD)
                np->multiplier  = 4;
        else if (np->features & FE_DBLR)
                np->multiplier  = 2;
        else
                np->multiplier  = 1;

        /*
         *  Measure SCSI clock frequency for chips 
         *  it may vary from assumed one.
         */
        if (np->features & FE_VARCLK)
                sym_getclock(np, np->multiplier);

        /*
         * Divisor to be used for async (timer pre-scaler).
         */
        i = np->clock_divn - 1;
        while (--i >= 0) {
                if (10ul * SYM_CONF_MIN_ASYNC * np->clock_khz > div_10M[i]) {
                        ++i;
                        break;
                }
        }
        np->rv_scntl3 = i+1;

        /*
         * The C1010 uses hardwired divisors for async.
         * So, we just throw away, the async. divisor.:-)
         */
        if (np->features & FE_C10)
                np->rv_scntl3 = 0;

        /*
         * Minimum synchronous period factor supported by the chip.
         * Btw, 'period' is in tenths of nanoseconds.
         */
        period = (4 * div_10M[0] + np->clock_khz - 1) / np->clock_khz;

        if      (period <= 250)         np->minsync = 10;
        else if (period <= 303)         np->minsync = 11;
        else if (period <= 500)         np->minsync = 12;
        else                            np->minsync = (period + 40 - 1) / 40;

        /*
         * Check against chip SCSI standard support (SCSI-2,ULTRA,ULTRA2).
         */
        if      (np->minsync < 25 &&
                 !(np->features & (FE_ULTRA|FE_ULTRA2|FE_ULTRA3)))
                np->minsync = 25;
        else if (np->minsync < 12 &&
                 !(np->features & (FE_ULTRA2|FE_ULTRA3)))
                np->minsync = 12;

        /*
         * Maximum synchronous period factor supported by the chip.
         */
        period = (11 * div_10M[np->clock_divn - 1]) / (4 * np->clock_khz);
        np->maxsync = period > 2540 ? 254 : period / 10;

        /*
         * If chip is a C1010, guess the sync limits in DT mode.
         */
        if ((np->features & (FE_C10|FE_ULTRA3)) == (FE_C10|FE_ULTRA3)) {
                if (np->clock_khz == 160000) {
                        np->minsync_dt = 9;
                        np->maxsync_dt = 50;
                        np->maxoffs_dt = nvram->type ? 62 : 31;
                }
        }
        
        /*
         *  64 bit addressing  (895A/896/1010) ?
         */
        if (np->features & FE_DAC) {
#if   SYM_CONF_DMA_ADDRESSING_MODE == 0
                np->rv_ccntl1   |= (DDAC);
#elif SYM_CONF_DMA_ADDRESSING_MODE == 1
                if (!np->use_dac)
                        np->rv_ccntl1   |= (DDAC);
                else
                        np->rv_ccntl1   |= (XTIMOD | EXTIBMV);
#elif SYM_CONF_DMA_ADDRESSING_MODE == 2
                if (!np->use_dac)
                        np->rv_ccntl1   |= (DDAC);
                else
                        np->rv_ccntl1   |= (0 | EXTIBMV);
#endif
        }

        /*
         *  Phase mismatch handled by SCRIPTS (895A/896/1010) ?
         */
        if (np->features & FE_NOPM)
                np->rv_ccntl0   |= (ENPMJ);

        /*
         *  C1010-33 Errata: Part Number:609-039638 (rev. 1) is fixed.
         *  In dual channel mode, contention occurs if internal cycles
         *  are used. Disable internal cycles.
         */
        if (np->device_id == PCI_DEVICE_ID_LSI_53C1010_33 &&
            np->revision_id < 0x1)
                np->rv_ccntl0   |=  DILS;

        /*
         *  Select burst length (dwords)
         */
        burst_max       = SYM_SETUP_BURST_ORDER;
        if (burst_max == 255)
                burst_max = burst_code(np->sv_dmode, np->sv_ctest4,
                                       np->sv_ctest5);
        if (burst_max > 7)
                burst_max = 7;
        if (burst_max > np->maxburst)
                burst_max = np->maxburst;

        /*
         *  DEL 352 - 53C810 Rev x11 - Part Number 609-0392140 - ITEM 2.
         *  This chip and the 860 Rev 1 may wrongly use PCI cache line 
         *  based transactions on LOAD/STORE instructions. So we have 
         *  to prevent these chips from using such PCI transactions in 
         *  this driver. The generic ncr driver that does not use 
         *  LOAD/STORE instructions does not need this work-around.
         */
        if ((np->device_id == PCI_DEVICE_ID_NCR_53C810 &&
             np->revision_id >= 0x10 && np->revision_id <= 0x11) ||
            (np->device_id == PCI_DEVICE_ID_NCR_53C860 &&
             np->revision_id <= 0x1))
                np->features &= ~(FE_WRIE|FE_ERL|FE_ERMP);

        /*
         *  Select all supported special features.
         *  If we are using on-board RAM for scripts, prefetch (PFEN) 
         *  does not help, but burst op fetch (BOF) does.
         *  Disabling PFEN makes sure BOF will be used.
         */
        if (np->features & FE_ERL)
                np->rv_dmode    |= ERL;         /* Enable Read Line */
        if (np->features & FE_BOF)
                np->rv_dmode    |= BOF;         /* Burst Opcode Fetch */
        if (np->features & FE_ERMP)
                np->rv_dmode    |= ERMP;        /* Enable Read Multiple */
#if 1
        if ((np->features & FE_PFEN) && !np->ram_ba)
#else
        if (np->features & FE_PFEN)
#endif
                np->rv_dcntl    |= PFEN;        /* Prefetch Enable */
        if (np->features & FE_CLSE)
                np->rv_dcntl    |= CLSE;        /* Cache Line Size Enable */
        if (np->features & FE_WRIE)
                np->rv_ctest3   |= WRIE;        /* Write and Invalidate */
        if (np->features & FE_DFS)
                np->rv_ctest5   |= DFS;         /* Dma Fifo Size */

        /*
         *  Select some other
         */
        np->rv_ctest4   |= MPEE; /* Master parity checking */
        np->rv_scntl0   |= 0x0a; /*  full arb., ena parity, par->ATN  */

        /*
         *  Get parity checking, host ID and verbose mode from NVRAM
         */
        np->myaddr = 255;
        sym_nvram_setup_host(shost, np, nvram);

        /*
         *  Get SCSI addr of host adapter (set by bios?).
         */
        if (np->myaddr == 255) {
                np->myaddr = INB(np, nc_scid) & 0x07;
                if (!np->myaddr)
                        np->myaddr = SYM_SETUP_HOST_ID;
        }

        /*
         *  Prepare initial io register bits for burst length
         */
        sym_init_burst(np, burst_max);

        /*
         *  Set SCSI BUS mode.
         *  - LVD capable chips (895/895A/896/1010) report the 
         *    current BUS mode through the STEST4 IO register.
         *  - For previous generation chips (825/825A/875), 
         *    user has to tell us how to check against HVD, 
         *    since a 100% safe algorithm is not possible.
         */
        np->scsi_mode = SMODE_SE;
        if (np->features & (FE_ULTRA2|FE_ULTRA3))
                np->scsi_mode = (np->sv_stest4 & SMODE);
        else if (np->features & FE_DIFF) {
                if (SYM_SETUP_SCSI_DIFF == 1) {
                        if (np->sv_scntl3) {
                                if (np->sv_stest2 & 0x20)
                                        np->scsi_mode = SMODE_HVD;
                        }
                        else if (nvram->type == SYM_SYMBIOS_NVRAM) {
                                if (!(INB(np, nc_gpreg) & 0x08))
                                        np->scsi_mode = SMODE_HVD;
                        }
                }
                else if (SYM_SETUP_SCSI_DIFF == 2)
                        np->scsi_mode = SMODE_HVD;
        }
        if (np->scsi_mode == SMODE_HVD)
                np->rv_stest2 |= 0x20;

        /*
         *  Set LED support from SCRIPTS.
         *  Ignore this feature for boards known to use a 
         *  specific GPIO wiring and for the 895A, 896 
         *  and 1010 that drive the LED directly.
         */
        if ((SYM_SETUP_SCSI_LED || 
             (nvram->type == SYM_SYMBIOS_NVRAM ||
              (nvram->type == SYM_TEKRAM_NVRAM &&
               np->device_id == PCI_DEVICE_ID_NCR_53C895))) &&
            !(np->features & FE_LEDC) && !(np->sv_gpcntl & 0x01))
                np->features |= FE_LED0;

        /*
         *  Set irq mode.
         */
        switch(SYM_SETUP_IRQ_MODE & 3) {
        case 2:
                np->rv_dcntl    |= IRQM;
                break;
        case 1:
                np->rv_dcntl    |= (np->sv_dcntl & IRQM);
                break;
        default:
                break;
        }

        /*
         *  Configure targets according to driver setup.
         *  If NVRAM present get targets setup from NVRAM.
         */
        for (i = 0 ; i < SYM_CONF_MAX_TARGET ; i++) {
                struct sym_tcb *tp = &np->target[i];

                tp->usrflags |= (SYM_DISC_ENABLED | SYM_TAGS_ENABLED);
                tp->usrtags = SYM_SETUP_MAX_TAG;

                sym_nvram_setup_target(np, i, nvram);

                if (!tp->usrtags)
                        tp->usrflags &= ~SYM_TAGS_ENABLED;
        }

        /*
         *  Let user know about the settings.
         */
        printf("%s: %s, ID %d, Fast-%d, %s, %s\n", sym_name(np),
                sym_nvram_type(nvram), np->myaddr,
                (np->features & FE_ULTRA3) ? 80 : 
                (np->features & FE_ULTRA2) ? 40 : 
                (np->features & FE_ULTRA)  ? 20 : 10,
                sym_scsi_bus_mode(np->scsi_mode),
                (np->rv_scntl0 & 0xa)   ? "parity checking" : "NO parity");
        /*
         *  Tell him more on demand.
         */
        if (sym_verbose) {
                printf("%s: %s IRQ line driver%s\n",
                        sym_name(np),
                        np->rv_dcntl & IRQM ? "totem pole" : "open drain",
                        np->ram_ba ? ", using on-chip SRAM" : "");
                printf("%s: using %s firmware.\n", sym_name(np), np->fw_name);
                if (np->features & FE_NOPM)
                        printf("%s: handling phase mismatch from SCRIPTS.\n", 
                               sym_name(np));
        }
        /*
         *  And still more.
         */
        if (sym_verbose >= 2) {
                printf ("%s: initial SCNTL3/DMODE/DCNTL/CTEST3/4/5 = "
                        "(hex) %02x/%02x/%02x/%02x/%02x/%02x\n",
                        sym_name(np), np->sv_scntl3, np->sv_dmode, np->sv_dcntl,
                        np->sv_ctest3, np->sv_ctest4, np->sv_ctest5);

                printf ("%s: final   SCNTL3/DMODE/DCNTL/CTEST3/4/5 = "
                        "(hex) %02x/%02x/%02x/%02x/%02x/%02x\n",
                        sym_name(np), np->rv_scntl3, np->rv_dmode, np->rv_dcntl,
                        np->rv_ctest3, np->rv_ctest4, np->rv_ctest5);
        }
        /*
         *  Let user be aware of targets that have some disable flags set.
         */
        sym_print_targets_flag(np, SYM_SCAN_BOOT_DISABLED, "SCAN AT BOOT");
        if (sym_verbose)
                sym_print_targets_flag(np, SYM_SCAN_LUNS_DISABLED,
                                       "SCAN FOR LUNS");

        return 0;
}

/*
 *  Test the pci bus snoop logic :-(
 *
 *  Has to be called with interrupts disabled.
 */
#ifndef CONFIG_SCSI_SYM53C8XX_IOMAPPED
static int sym_regtest (struct sym_hcb *np)
{
        register volatile u32 data;
        /*
         *  chip registers may NOT be cached.
         *  write 0xffffffff to a read only register area,
         *  and try to read it back.
         */
        data = 0xffffffff;
        OUTL(np, nc_dstat, data);
        data = INL(np, nc_dstat);
#if 1
        if (data == 0xffffffff) {
#else
        if ((data & 0xe2f0fffd) != 0x02000080) {
#endif
                printf ("CACHE TEST FAILED: reg dstat-sstat2 readback %x.\n",
                        (unsigned) data);
                return (0x10);
        }
        return (0);
}
#endif

static int sym_snooptest (struct sym_hcb *np)
{
        u32     sym_rd, sym_wr, sym_bk, host_rd, host_wr, pc, dstat;
        int     i, err=0;
#ifndef CONFIG_SCSI_SYM53C8XX_IOMAPPED
        err |= sym_regtest (np);
        if (err) return (err);
#endif
restart_test:
        /*
         *  Enable Master Parity Checking as we intend 
         *  to enable it for normal operations.
         */
        OUTB(np, nc_ctest4, (np->rv_ctest4 & MPEE));
        /*
         *  init
         */
        pc  = SCRIPTZ_BA(np, snooptest);
        host_wr = 1;
        sym_wr  = 2;
        /*
         *  Set memory and register.
         */
        np->scratch = cpu_to_scr(host_wr);
        OUTL(np, nc_temp, sym_wr);
        /*
         *  Start script (exchange values)
         */
        OUTL(np, nc_dsa, np->hcb_ba);
        OUTL_DSP(np, pc);
        /*
         *  Wait 'til done (with timeout)
         */
        for (i=0; i<SYM_SNOOP_TIMEOUT; i++)
                if (INB(np, nc_istat) & (INTF|SIP|DIP))
                        break;
        if (i>=SYM_SNOOP_TIMEOUT) {
                printf ("CACHE TEST FAILED: timeout.\n");
                return (0x20);
        }
        /*
         *  Check for fatal DMA errors.
         */
        dstat = INB(np, nc_dstat);
#if 1   /* Band aiding for broken hardwares that fail PCI parity */
        if ((dstat & MDPE) && (np->rv_ctest4 & MPEE)) {
                printf ("%s: PCI DATA PARITY ERROR DETECTED - "
                        "DISABLING MASTER DATA PARITY CHECKING.\n",
                        sym_name(np));
                np->rv_ctest4 &= ~MPEE;
                goto restart_test;
        }
#endif
        if (dstat & (MDPE|BF|IID)) {
                printf ("CACHE TEST FAILED: DMA error (dstat=0x%02x).", dstat);
                return (0x80);
        }
        /*
         *  Save termination position.
         */
        pc = INL(np, nc_dsp);
        /*
         *  Read memory and register.
         */
        host_rd = scr_to_cpu(np->scratch);
        sym_rd  = INL(np, nc_scratcha);
        sym_bk  = INL(np, nc_temp);
        /*
         *  Check termination position.
         */
        if (pc != SCRIPTZ_BA(np, snoopend)+8) {
                printf ("CACHE TEST FAILED: script execution failed.\n");
                printf ("start=%08lx, pc=%08lx, end=%08lx\n", 
                        (u_long) SCRIPTZ_BA(np, snooptest), (u_long) pc,
                        (u_long) SCRIPTZ_BA(np, snoopend) +8);
                return (0x40);
        }
        /*
         *  Show results.
         */
        if (host_wr != sym_rd) {
                printf ("CACHE TEST FAILED: host wrote %d, chip read %d.\n",
                        (int) host_wr, (int) sym_rd);
                err |= 1;
        }
        if (host_rd != sym_wr) {
                printf ("CACHE TEST FAILED: chip wrote %d, host read %d.\n",
                        (int) sym_wr, (int) host_rd);
                err |= 2;
        }
        if (sym_bk != sym_wr) {
                printf ("CACHE TEST FAILED: chip wrote %d, read back %d.\n",
                        (int) sym_wr, (int) sym_bk);
                err |= 4;
        }

        return (err);
}

/*
 *  log message for real hard errors
 *
 *  sym0 targ 0?: ERROR (ds:si) (so-si-sd) (sx/s3/s4) @ name (dsp:dbc).
 *            reg: r0 r1 r2 r3 r4 r5 r6 ..... rf.
 *
 *  exception register:
 *      ds:     dstat
 *      si:     sist
 *
 *  SCSI bus lines:
 *      so:     control lines as driven by chip.
 *      si:     control lines as seen by chip.
 *      sd:     scsi data lines as seen by chip.
 *
 *  wide/fastmode:
 *      sx:     sxfer  (see the manual)
 *      s3:     scntl3 (see the manual)
 *      s4:     scntl4 (see the manual)
 *
 *  current script command:
 *      dsp:    script address (relative to start of script).
 *      dbc:    first word of script command.
 *
 *  First 24 register of the chip:
 *      r0..rf
 */
static void sym_log_hard_error(struct sym_hcb *np, u_short sist, u_char dstat)
{
        u32     dsp;
        int     script_ofs;
        int     script_size;
        char    *script_name;
        u_char  *script_base;
        int     i;

        dsp     = INL(np, nc_dsp);

        if      (dsp > np->scripta_ba &&
                 dsp <= np->scripta_ba + np->scripta_sz) {
                script_ofs      = dsp - np->scripta_ba;
                script_size     = np->scripta_sz;
                script_base     = (u_char *) np->scripta0;
                script_name     = "scripta";
        }
        else if (np->scriptb_ba < dsp && 
                 dsp <= np->scriptb_ba + np->scriptb_sz) {
                script_ofs      = dsp - np->scriptb_ba;
                script_size     = np->scriptb_sz;
                script_base     = (u_char *) np->scriptb0;
                script_name     = "scriptb";
        } else {
                script_ofs      = dsp;
                script_size     = 0;
                script_base     = NULL;
                script_name     = "mem";
        }

        printf ("%s:%d: ERROR (%x:%x) (%x-%x-%x) (%x/%x/%x) @ (%s %x:%08x).\n",
                sym_name(np), (unsigned)INB(np, nc_sdid)&0x0f, dstat, sist,
                (unsigned)INB(np, nc_socl), (unsigned)INB(np, nc_sbcl),
                (unsigned)INB(np, nc_sbdl), (unsigned)INB(np, nc_sxfer),
                (unsigned)INB(np, nc_scntl3),
                (np->features & FE_C10) ?  (unsigned)INB(np, nc_scntl4) : 0,
                script_name, script_ofs,   (unsigned)INL(np, nc_dbc));

        if (((script_ofs & 3) == 0) &&
            (unsigned)script_ofs < script_size) {
                printf ("%s: script cmd = %08x\n", sym_name(np),
                        scr_to_cpu((int) *(u32 *)(script_base + script_ofs)));
        }

        printf ("%s: regdump:", sym_name(np));
        for (i=0; i<24;i++)
            printf (" %02x", (unsigned)INB_OFF(np, i));
        printf (".\n");

        /*
         *  PCI BUS error.
         */
        if (dstat & (MDPE|BF))
                sym_log_bus_error(np);
}

static struct sym_chip sym_dev_table[] = {
 {PCI_DEVICE_ID_NCR_53C810, 0x0f, "810", 4, 8, 4, 64,
 FE_ERL}
 ,
#ifdef SYM_DEBUG_GENERIC_SUPPORT
 {PCI_DEVICE_ID_NCR_53C810, 0xff, "810a", 4,  8, 4, 1,
 FE_BOF}
 ,
#else
 {PCI_DEVICE_ID_NCR_53C810, 0xff, "810a", 4,  8, 4, 1,
 FE_CACHE_SET|FE_LDSTR|FE_PFEN|FE_BOF}
 ,
#endif
 {PCI_DEVICE_ID_NCR_53C815, 0xff, "815", 4,  8, 4, 64,
 FE_BOF|FE_ERL}
 ,
 {PCI_DEVICE_ID_NCR_53C825, 0x0f, "825", 6,  8, 4, 64,
 FE_WIDE|FE_BOF|FE_ERL|FE_DIFF}
 ,
 {PCI_DEVICE_ID_NCR_53C825, 0xff, "825a", 6,  8, 4, 2,
 FE_WIDE|FE_CACHE0_SET|FE_BOF|FE_DFS|FE_LDSTR|FE_PFEN|FE_RAM|FE_DIFF}
 ,
 {PCI_DEVICE_ID_NCR_53C860, 0xff, "860", 4,  8, 5, 1,
 FE_ULTRA|FE_CACHE_SET|FE_BOF|FE_LDSTR|FE_PFEN}
 ,
 {PCI_DEVICE_ID_NCR_53C875, 0x01, "875", 6, 16, 5, 2,
 FE_WIDE|FE_ULTRA|FE_CACHE0_SET|FE_BOF|FE_DFS|FE_LDSTR|FE_PFEN|
 FE_RAM|FE_DIFF|FE_VARCLK}
 ,
 {PCI_DEVICE_ID_NCR_53C875, 0xff, "875", 6, 16, 5, 2,
 FE_WIDE|FE_ULTRA|FE_DBLR|FE_CACHE0_SET|FE_BOF|FE_DFS|FE_LDSTR|FE_PFEN|
 FE_RAM|FE_DIFF|FE_VARCLK}
 ,
 {PCI_DEVICE_ID_NCR_53C875J, 0xff, "875J", 6, 16, 5, 2,
 FE_WIDE|FE_ULTRA|FE_DBLR|FE_CACHE0_SET|FE_BOF|FE_DFS|FE_LDSTR|FE_PFEN|
 FE_RAM|FE_DIFF|FE_VARCLK}
 ,
 {PCI_DEVICE_ID_NCR_53C885, 0xff, "885", 6, 16, 5, 2,
 FE_WIDE|FE_ULTRA|FE_DBLR|FE_CACHE0_SET|FE_BOF|FE_DFS|FE_LDSTR|FE_PFEN|
 FE_RAM|FE_DIFF|FE_VARCLK}
 ,
#ifdef SYM_DEBUG_GENERIC_SUPPORT
 {PCI_DEVICE_ID_NCR_53C895, 0xff, "895", 6, 31, 7, 2,
 FE_WIDE|FE_ULTRA2|FE_QUAD|FE_CACHE_SET|FE_BOF|FE_DFS|
 FE_RAM|FE_LCKFRQ}
 ,
#else
 {PCI_DEVICE_ID_NCR_53C895, 0xff, "895", 6, 31, 7, 2,
 FE_WIDE|FE_ULTRA2|FE_QUAD|FE_CACHE_SET|FE_BOF|FE_DFS|FE_LDSTR|FE_PFEN|
 FE_RAM|FE_LCKFRQ}
 ,
#endif
 {PCI_DEVICE_ID_NCR_53C896, 0xff, "896", 6, 31, 7, 4,
 FE_WIDE|FE_ULTRA2|FE_QUAD|FE_CACHE_SET|FE_BOF|FE_DFS|FE_LDSTR|FE_PFEN|
 FE_RAM|FE_RAM8K|FE_64BIT|FE_DAC|FE_IO256|FE_NOPM|FE_LEDC|FE_LCKFRQ}
 ,
 {PCI_DEVICE_ID_LSI_53C895A, 0xff, "895a", 6, 31, 7, 4,
 FE_WIDE|FE_ULTRA2|FE_QUAD|FE_CACHE_SET|FE_BOF|FE_DFS|FE_LDSTR|FE_PFEN|
 FE_RAM|FE_RAM8K|FE_DAC|FE_IO256|FE_NOPM|FE_LEDC|FE_LCKFRQ}
 ,
 {PCI_DEVICE_ID_LSI_53C875A, 0xff, "875a", 6, 31, 7, 4,
 FE_WIDE|FE_ULTRA|FE_QUAD|FE_CACHE_SET|FE_BOF|FE_DFS|FE_LDSTR|FE_PFEN|
 FE_RAM|FE_DAC|FE_IO256|FE_NOPM|FE_LEDC|FE_LCKFRQ}
 ,
 {PCI_DEVICE_ID_LSI_53C1010_33, 0x00, "1010-33", 6, 31, 7, 8,
 FE_WIDE|FE_ULTRA3|FE_QUAD|FE_CACHE_SET|FE_BOF|FE_DFBC|FE_LDSTR|FE_PFEN|
 FE_RAM|FE_RAM8K|FE_64BIT|FE_DAC|FE_IO256|FE_NOPM|FE_LEDC|FE_CRC|
 FE_C10}
 ,
 {PCI_DEVICE_ID_LSI_53C1010_33, 0xff, "1010-33", 6, 31, 7, 8,
 FE_WIDE|FE_ULTRA3|FE_QUAD|FE_CACHE_SET|FE_BOF|FE_DFBC|FE_LDSTR|FE_PFEN|
 FE_RAM|FE_RAM8K|FE_64BIT|FE_DAC|FE_IO256|FE_NOPM|FE_LEDC|FE_CRC|
 FE_C10|FE_U3EN}
 ,
 {PCI_DEVICE_ID_LSI_53C1010_66, 0xff, "1010-66", 6, 31, 7, 8,
 FE_WIDE|FE_ULTRA3|FE_QUAD|FE_CACHE_SET|FE_BOF|FE_DFBC|FE_LDSTR|FE_PFEN|
 FE_RAM|FE_RAM8K|FE_64BIT|FE_DAC|FE_IO256|FE_NOPM|FE_LEDC|FE_66MHZ|FE_CRC|
 FE_C10|FE_U3EN}
 ,
 {PCI_DEVICE_ID_LSI_53C1510, 0xff, "1510d", 6, 31, 7, 4,
 FE_WIDE|FE_ULTRA2|FE_QUAD|FE_CACHE_SET|FE_BOF|FE_DFS|FE_LDSTR|FE_PFEN|
 FE_RAM|FE_IO256|FE_LEDC}
};

#define sym_num_devs \
        (sizeof(sym_dev_table) / sizeof(sym_dev_table[0]))

/*
 *  Look up the chip table.
 *
 *  Return a pointer to the chip entry if found, 
 *  zero otherwise.
 */
struct sym_chip *
sym_lookup_chip_table (u_short device_id, u_char revision)
{
        struct  sym_chip *chip;
        int     i;

        for (i = 0; i < sym_num_devs; i++) {
                chip = &sym_dev_table[i];
                if (device_id != chip->device_id)
                        continue;
                if (revision > chip->revision_id)
                        continue;
                return chip;
        }

        return NULL;
}

#if SYM_CONF_DMA_ADDRESSING_MODE == 2
/*
 *  Lookup the 64 bit DMA segments map.
 *  This is only used if the direct mapping 
 *  has been unsuccessful.
 */
int sym_lookup_dmap(struct sym_hcb *np, u32 h, int s)
{
        int i;

        if (!np->use_dac)
                goto weird;

        /* Look up existing mappings */
        for (i = SYM_DMAP_SIZE-1; i > 0; i--) {
                if (h == np->dmap_bah[i])
                        return i;
        }
        /* If direct mapping is free, get it */
        if (!np->dmap_bah[s])
                goto new;
        /* Collision -> lookup free mappings */
        for (s = SYM_DMAP_SIZE-1; s > 0; s--) {
                if (!np->dmap_bah[s])
                        goto new;
        }
weird:
        panic("sym: ran out of 64 bit DMA segment registers");
        return -1;
new:
        np->dmap_bah[s] = h;
        np->dmap_dirty = 1;
        return s;
}

/*
 *  Update IO registers scratch C..R so they will be 
 *  in sync. with queued CCB expectations.
 */
static void sym_update_dmap_regs(struct sym_hcb *np)
{
        int o, i;

        if (!np->dmap_dirty)
                return;
        o = offsetof(struct sym_reg, nc_scrx[0]);
        for (i = 0; i < SYM_DMAP_SIZE; i++) {
                OUTL_OFF(np, o, np->dmap_bah[i]);
                o += 4;
        }
        np->dmap_dirty = 0;
}
#endif

/* Enforce all the fiddly SPI rules and the chip limitations */
static void sym_check_goals(struct sym_hcb *np, struct scsi_target *starget,
                struct sym_trans *goal)
{
        if (!spi_support_wide(starget))
                goal->width = 0;

        if (!spi_support_sync(starget)) {
                goal->iu = 0;
                goal->dt = 0;
                goal->qas = 0;
                goal->period = 0;
                goal->offset = 0;
                return;
        }

        if (spi_support_dt(starget)) {
                if (spi_support_dt_only(starget))
                        goal->dt = 1;

                if (goal->offset == 0)
                        goal->dt = 0;
        } else {
                goal->dt = 0;
        }

        /* Some targets fail to properly negotiate DT in SE mode */
        if ((np->scsi_mode != SMODE_LVD) || !(np->features & FE_U3EN))
                goal->dt = 0;

        if (goal->dt) {
                /* all DT transfers must be wide */
                goal->width = 1;
                if (goal->offset > np->maxoffs_dt)
                        goal->offset = np->maxoffs_dt;
                if (goal->period < np->minsync_dt)
                        goal->period = np->minsync_dt;
                if (goal->period > np->maxsync_dt)
                        goal->period = np->maxsync_dt;
        } else {
                goal->iu = goal->qas = 0;
                if (goal->offset > np->maxoffs)
                        goal->offset = np->maxoffs;
                if (goal->period < np->minsync)
                        goal->period = np->minsync;
                if (goal->period > np->maxsync)
                        goal->period = np->maxsync;
        }
}

/*
 *  Prepare the next negotiation message if needed.
 *
 *  Fill in the part of message buffer that contains the 
 *  negotiation and the nego_status field of the CCB.
 *  Returns the size of the message in bytes.
 */
static int sym_prepare_nego(struct sym_hcb *np, struct sym_ccb *cp, u_char *msgptr)
{
        struct sym_tcb *tp = &np->target[cp->target];
        struct scsi_target *starget = tp->starget;
        struct sym_trans *goal = &tp->tgoal;
        int msglen = 0;
        int nego;

        sym_check_goals(np, starget, goal);

        /*
         * Many devices implement PPR in a buggy way, so only use it if we
         * really want to.
         */
        if (goal->iu || goal->dt || goal->qas || (goal->period < 0xa)) {
                nego = NS_PPR;
        } else if (spi_width(starget) != goal->width) {
                nego = NS_WIDE;
        } else if (spi_period(starget) != goal->period ||
                   spi_offset(starget) != goal->offset) {
                nego = NS_SYNC;
        } else {
                goal->check_nego = 0;
                nego = 0;
        }

        switch (nego) {
        case NS_SYNC:
                msgptr[msglen++] = M_EXTENDED;
                msgptr[msglen++] = 3;
                msgptr[msglen++] = M_X_SYNC_REQ;
                msgptr[msglen++] = goal->period;
                msgptr[msglen++] = goal->offset;
                break;
        case NS_WIDE:
                msgptr[msglen++] = M_EXTENDED;
                msgptr[msglen++] = 2;
                msgptr[msglen++] = M_X_WIDE_REQ;
                msgptr[msglen++] = goal->width;
                break;
        case NS_PPR:
                msgptr[msglen++] = M_EXTENDED;
                msgptr[msglen++] = 6;
                msgptr[msglen++] = M_X_PPR_REQ;
                msgptr[msglen++] = goal->period;
                msgptr[msglen++] = 0;
                msgptr[msglen++] = goal->offset;
                msgptr[msglen++] = goal->width;
                msgptr[msglen++] = (goal->iu ? PPR_OPT_IU : 0) |
                                        (goal->dt ? PPR_OPT_DT : 0) |
                                        (goal->qas ? PPR_OPT_QAS : 0);
                break;
        }

        cp->nego_status = nego;

        if (nego) {
                tp->nego_cp = cp; /* Keep track a nego will be performed */
                if (DEBUG_FLAGS & DEBUG_NEGO) {
                        sym_print_nego_msg(np, cp->target, 
                                          nego == NS_SYNC ? "sync msgout" :
                                          nego == NS_WIDE ? "wide msgout" :
                                          "ppr msgout", msgptr);
                }
        }

        return msglen;
}

/*
 *  Insert a job into the start queue.
 */
static void sym_put_start_queue(struct sym_hcb *np, struct sym_ccb *cp)
{
        u_short qidx;

#ifdef SYM_CONF_IARB_SUPPORT
        /*
         *  If the previously queued CCB is not yet done, 
         *  set the IARB hint. The SCRIPTS will go with IARB 
         *  for this job when starting the previous one.
         *  We leave devices a chance to win arbitration by 
         *  not using more than 'iarb_max' consecutive 
         *  immediate arbitrations.
         */
        if (np->last_cp && np->iarb_count < np->iarb_max) {
                np->last_cp->host_flags |= HF_HINT_IARB;
                ++np->iarb_count;
        }
        else
                np->iarb_count = 0;
        np->last_cp = cp;
#endif

#if   SYM_CONF_DMA_ADDRESSING_MODE == 2
        /*
         *  Make SCRIPTS aware of the 64 bit DMA 
         *  segment registers not being up-to-date.
         */
        if (np->dmap_dirty)
                cp->host_xflags |= HX_DMAP_DIRTY;
#endif

        /*
         *  Insert first the idle task and then our job.
         *  The MBs should ensure proper ordering.
         */
        qidx = np->squeueput + 2;
        if (qidx >= MAX_QUEUE*2) qidx = 0;

        np->squeue [qidx]          = cpu_to_scr(np->idletask_ba);
        MEMORY_WRITE_BARRIER();
        np->squeue [np->squeueput] = cpu_to_scr(cp->ccb_ba);

        np->squeueput = qidx;

        if (DEBUG_FLAGS & DEBUG_QUEUE)
                printf ("%s: queuepos=%d.\n", sym_name (np), np->squeueput);

        /*
         *  Script processor may be waiting for reselect.
         *  Wake it up.
         */
        MEMORY_WRITE_BARRIER();
        OUTB(np, nc_istat, SIGP|np->istat_sem);
}

#ifdef SYM_OPT_HANDLE_DEVICE_QUEUEING
/*
 *  Start next ready-to-start CCBs.
 */
void sym_start_next_ccbs(struct sym_hcb *np, struct sym_lcb *lp, int maxn)
{
        SYM_QUEHEAD *qp;
        struct sym_ccb *cp;

        /* 
         *  Paranoia, as usual. :-)
         */
        assert(!lp->started_tags || !lp->started_no_tag);

        /*
         *  Try to start as many commands as asked by caller.
         *  Prevent from having both tagged and untagged 
         *  commands queued to the device at the same time.
         */
        while (maxn--) {
                qp = sym_remque_head(&lp->waiting_ccbq);
                if (!qp)
                        break;
                cp = sym_que_entry(qp, struct sym_ccb, link2_ccbq);
                if (cp->tag != NO_TAG) {
                        if (lp->started_no_tag ||
                            lp->started_tags >= lp->started_max) {
                                sym_insque_head(qp, &lp->waiting_ccbq);
                                break;
                        }
                        lp->itlq_tbl[cp->tag] = cpu_to_scr(cp->ccb_ba);
                        lp->head.resel_sa =
                                cpu_to_scr(SCRIPTA_BA(np, resel_tag));
                        ++lp->started_tags;
                } else {
                        if (lp->started_no_tag || lp->started_tags) {
                                sym_insque_head(qp, &lp->waiting_ccbq);
                                break;
                        }
                        lp->head.itl_task_sa = cpu_to_scr(cp->ccb_ba);
                        lp->head.resel_sa =
                              cpu_to_scr(SCRIPTA_BA(np, resel_no_tag));
                        ++lp->started_no_tag;
                }
                cp->started = 1;
                sym_insque_tail(qp, &lp->started_ccbq);
                sym_put_start_queue(np, cp);
        }
}
#endif /* SYM_OPT_HANDLE_DEVICE_QUEUEING */

/*
 *  The chip may have completed jobs. Look at the DONE QUEUE.
 *
 *  On paper, memory read barriers may be needed here to 
 *  prevent out of order LOADs by the CPU from having 
 *  prefetched stale data prior to DMA having occurred.
 */
static int sym_wakeup_done (struct sym_hcb *np)
{
        struct sym_ccb *cp;
        int i, n;
        u32 dsa;

        n = 0;
        i = np->dqueueget;

        /* MEMORY_READ_BARRIER(); */
        while (1) {
                dsa = scr_to_cpu(np->dqueue[i]);
                if (!dsa)
                        break;
                np->dqueue[i] = 0;
                if ((i = i+2) >= MAX_QUEUE*2)
                        i = 0;

                cp = sym_ccb_from_dsa(np, dsa);
                if (cp) {
                        MEMORY_READ_BARRIER();
                        sym_complete_ok (np, cp);
                        ++n;
                }
                else
                        printf ("%s: bad DSA (%x) in done queue.\n",
                                sym_name(np), (u_int) dsa);
        }
        np->dqueueget = i;

        return n;
}

/*
 *  Complete all CCBs queued to the COMP queue.
 *
 *  These CCBs are assumed:
 *  - Not to be referenced either by devices or 
 *    SCRIPTS-related queues and datas.
 *  - To have to be completed with an error condition 
 *    or requeued.
 *
 *  The device queue freeze count is incremented 
 *  for each CCB that does not prevent this.
 *  This function is called when all CCBs involved 
 *  in error handling/recovery have been reaped.
 */
static void sym_flush_comp_queue(struct sym_hcb *np, int cam_status)
{
        SYM_QUEHEAD *qp;
        struct sym_ccb *cp;

        while ((qp = sym_remque_head(&np->comp_ccbq)) != 0) {
                struct scsi_cmnd *cmd;
                cp = sym_que_entry(qp, struct sym_ccb, link_ccbq);
                sym_insque_tail(&cp->link_ccbq, &np->busy_ccbq);
                /* Leave quiet CCBs waiting for resources */
                if (cp->host_status == HS_WAIT)
                        continue;
                cmd = cp->cmd;
                if (cam_status)
                        sym_set_cam_status(cmd, cam_status);
#ifdef SYM_OPT_HANDLE_DEVICE_QUEUEING
                if (sym_get_cam_status(cmd) == DID_SOFT_ERROR) {
                        struct sym_tcb *tp = &np->target[cp->target];
                        struct sym_lcb *lp = sym_lp(tp, cp->lun);
                        if (lp) {
                                sym_remque(&cp->link2_ccbq);
                                sym_insque_tail(&cp->link2_ccbq,
                                                &lp->waiting_ccbq);
                                if (cp->started) {
                                        if (cp->tag != NO_TAG)
                                                --lp->started_tags;
                                        else
                                                --lp->started_no_tag;
                                }
                        }
                        cp->started = 0;
                        continue;
                }
#endif
                sym_free_ccb(np, cp);
                sym_xpt_done(np, cmd);
        }
}

/*
 *  Complete all active CCBs with error.
 *  Used on CHIP/SCSI RESET.
 */
static void sym_flush_busy_queue (struct sym_hcb *np, int cam_status)
{
        /*
         *  Move all active CCBs to the COMP queue 
         *  and flush this queue.
         */
        sym_que_splice(&np->busy_ccbq, &np->comp_ccbq);
        sym_que_init(&np->busy_ccbq);
        sym_flush_comp_queue(np, cam_status);
}

/*
 *  Start chip.
 *
 *  'reason' means:
 *     0: initialisation.
 *     1: SCSI BUS RESET delivered or received.
 *     2: SCSI BUS MODE changed.
 */
void sym_start_up (struct sym_hcb *np, int reason)
{
        int     i;
        u32     phys;

        /*
         *  Reset chip if asked, otherwise just clear fifos.
         */
        if (reason == 1)
                sym_soft_reset(np);
        else {
                OUTB(np, nc_stest3, TE|CSF);
                OUTONB(np, nc_ctest3, CLF);
        }
 
        /*
         *  Clear Start Queue
         */
        phys = np->squeue_ba;
        for (i = 0; i < MAX_QUEUE*2; i += 2) {
                np->squeue[i]   = cpu_to_scr(np->idletask_ba);
                np->squeue[i+1] = cpu_to_scr(phys + (i+2)*4);
        }
        np->squeue[MAX_QUEUE*2-1] = cpu_to_scr(phys);

        /*
         *  Start at first entry.
         */
        np->squeueput = 0;

        /*
         *  Clear Done Queue
         */
        phys = np->dqueue_ba;
        for (i = 0; i < MAX_QUEUE*2; i += 2) {
                np->dqueue[i]   = 0;
                np->dqueue[i+1] = cpu_to_scr(phys + (i+2)*4);
        }
        np->dqueue[MAX_QUEUE*2-1] = cpu_to_scr(phys);

        /*
         *  Start at first entry.
         */
        np->dqueueget = 0;

        /*
         *  Install patches in scripts.
         *  This also let point to first position the start 
         *  and done queue pointers used from SCRIPTS.
         */
        np->fw_patch(np);

        /*
         *  Wakeup all pending jobs.
         */
        sym_flush_busy_queue(np, DID_RESET);

        /*
         *  Init chip.
         */
        OUTB(np, nc_istat,  0x00);                      /*  Remove Reset, abort */
        INB(np, nc_mbox1);
        udelay(2000); /* The 895 needs time for the bus mode to settle */

        OUTB(np, nc_scntl0, np->rv_scntl0 | 0xc0);
                                        /*  full arb., ena parity, par->ATN  */
        OUTB(np, nc_scntl1, 0x00);              /*  odd parity, and remove CRST!! */

        sym_selectclock(np, np->rv_scntl3);     /* Select SCSI clock */

        OUTB(np, nc_scid  , RRE|np->myaddr);    /* Adapter SCSI address */
        OUTW(np, nc_respid, 1ul<<np->myaddr);   /* Id to respond to */
        OUTB(np, nc_istat , SIGP        );              /*  Signal Process */
        OUTB(np, nc_dmode , np->rv_dmode);              /* Burst length, dma mode */
        OUTB(np, nc_ctest5, np->rv_ctest5);     /* Large fifo + large burst */

        OUTB(np, nc_dcntl , NOCOM|np->rv_dcntl);        /* Protect SFBR */
        OUTB(np, nc_ctest3, np->rv_ctest3);     /* Write and invalidate */
        OUTB(np, nc_ctest4, np->rv_ctest4);     /* Master parity checking */

        /* Extended Sreq/Sack filtering not supported on the C10 */
        if (np->features & FE_C10)
                OUTB(np, nc_stest2, np->rv_stest2);
        else
                OUTB(np, nc_stest2, EXT|np->rv_stest2);

        OUTB(np, nc_stest3, TE);                        /* TolerANT enable */
        OUTB(np, nc_stime0, 0x0c);                      /* HTH disabled  STO 0.25 sec */

        /*
         *  For now, disable AIP generation on C1010-66.
         */
        if (np->device_id == PCI_DEVICE_ID_LSI_53C1010_66)
                OUTB(np, nc_aipcntl1, DISAIP);

        /*
         *  C10101 rev. 0 errata.
         *  Errant SGE's when in narrow. Write bits 4 & 5 of
         *  STEST1 register to disable SGE. We probably should do 
         *  that from SCRIPTS for each selection/reselection, but 
         *  I just don't want. :)
         */
        if (np->device_id == PCI_DEVICE_ID_LSI_53C1010_33 &&
            np->revision_id < 1)
                OUTB(np, nc_stest1, INB(np, nc_stest1) | 0x30);

        /*
         *  DEL 441 - 53C876 Rev 5 - Part Number 609-0392787/2788 - ITEM 2.
         *  Disable overlapped arbitration for some dual function devices, 
         *  regardless revision id (kind of post-chip-design feature. ;-))
         */
        if (np->device_id == PCI_DEVICE_ID_NCR_53C875)
                OUTB(np, nc_ctest0, (1<<5));
        else if (np->device_id == PCI_DEVICE_ID_NCR_53C896)
                np->rv_ccntl0 |= DPR;

        /*
         *  Write CCNTL0/CCNTL1 for chips capable of 64 bit addressing 
         *  and/or hardware phase mismatch, since only such chips 
         *  seem to support those IO registers.
         */
        if (np->features & (FE_DAC|FE_NOPM)) {
                OUTB(np, nc_ccntl0, np->rv_ccntl0);
                OUTB(np, nc_ccntl1, np->rv_ccntl1);
        }

#if     SYM_CONF_DMA_ADDRESSING_MODE == 2
        /*
         *  Set up scratch C and DRS IO registers to map the 32 bit 
         *  DMA address range our data structures are located in.
         */
        if (np->use_dac) {
                np->dmap_bah[0] = 0;    /* ??? */
                OUTL(np, nc_scrx[0], np->dmap_bah[0]);
                OUTL(np, nc_drs, np->dmap_bah[0]);
        }
#endif

        /*
         *  If phase mismatch handled by scripts (895A/896/1010),
         *  set PM jump addresses.
         */
        if (np->features & FE_NOPM) {
                OUTL(np, nc_pmjad1, SCRIPTB_BA(np, pm_handle));
                OUTL(np, nc_pmjad2, SCRIPTB_BA(np, pm_handle));
        }

        /*
         *    Enable GPIO0 pin for writing if LED support from SCRIPTS.
         *    Also set GPIO5 and clear GPIO6 if hardware LED control.
         */
        if (np->features & FE_LED0)
                OUTB(np, nc_gpcntl, INB(np, nc_gpcntl) & ~0x01);
        else if (np->features & FE_LEDC)
                OUTB(np, nc_gpcntl, (INB(np, nc_gpcntl) & ~0x41) | 0x20);

        /*
         *      enable ints
         */
        OUTW(np, nc_sien , STO|HTH|MA|SGE|UDC|RST|PAR);
        OUTB(np, nc_dien , MDPE|BF|SSI|SIR|IID);

        /*
         *  For 895/6 enable SBMC interrupt and save current SCSI bus mode.
         *  Try to eat the spurious SBMC interrupt that may occur when 
         *  we reset the chip but not the SCSI BUS (at initialization).
         */
        if (np->features & (FE_ULTRA2|FE_ULTRA3)) {
                OUTONW(np, nc_sien, SBMC);
                if (reason == 0) {
                        INB(np, nc_mbox1);
                        mdelay(100);
                        INW(np, nc_sist);
                }
                np->scsi_mode = INB(np, nc_stest4) & SMODE;
        }

        /*
         *  Fill in target structure.
         *  Reinitialize usrsync.
         *  Reinitialize usrwide.
         *  Prepare sync negotiation according to actual SCSI bus mode.
         */
        for (i=0;i<SYM_CONF_MAX_TARGET;i++) {
                struct sym_tcb *tp = &np->target[i];

                tp->to_reset  = 0;
                tp->head.sval = 0;
                tp->head.wval = np->rv_scntl3;
                tp->head.uval = 0;
        }

        /*
         *  Download SCSI SCRIPTS to on-chip RAM if present,
         *  and start script processor.
         *  We do the download preferently from the CPU.
         *  For platforms that may not support PCI memory mapping,
         *  we use simple SCRIPTS that performs MEMORY MOVEs.
         */
        phys = SCRIPTA_BA(np, init);
        if (np->ram_ba) {
                if (sym_verbose >= 2)
                        printf("%s: Downloading SCSI SCRIPTS.\n", sym_name(np));
                memcpy_toio(np->s.ramaddr, np->scripta0, np->scripta_sz);
                if (np->ram_ws == 8192) {
                        memcpy_toio(np->s.ramaddr + 4096, np->scriptb0, np->scriptb_sz);
                        phys = scr_to_cpu(np->scr_ram_seg);
                        OUTL(np, nc_mmws, phys);
                        OUTL(np, nc_mmrs, phys);
                        OUTL(np, nc_sfs,  phys);
                        phys = SCRIPTB_BA(np, start64);
                }
        }

        np->istat_sem = 0;

        OUTL(np, nc_dsa, np->hcb_ba);
        OUTL_DSP(np, phys);

        /*
         *  Notify the XPT about the RESET condition.
         */
        if (reason != 0)
                sym_xpt_async_bus_reset(np);
}

/*
 *  Switch trans mode for current job and its target.
 */
static void sym_settrans(struct sym_hcb *np, int target, u_char opts, u_char ofs,
                         u_char per, u_char wide, u_char div, u_char fak)
{
        SYM_QUEHEAD *qp;
        u_char sval, wval, uval;
        struct sym_tcb *tp = &np->target[target];

        assert(target == (INB(np, nc_sdid) & 0x0f));

        sval = tp->head.sval;
        wval = tp->head.wval;
        uval = tp->head.uval;

#if 0
        printf("XXXX sval=%x wval=%x uval=%x (%x)\n", 
                sval, wval, uval, np->rv_scntl3);
#endif
        /*
         *  Set the offset.
         */
        if (!(np->features & FE_C10))
                sval = (sval & ~0x1f) | ofs;
        else
                sval = (sval & ~0x3f) | ofs;

        /*
         *  Set the sync divisor and extra clock factor.
         */
        if (ofs != 0) {
                wval = (wval & ~0x70) | ((div+1) << 4);
                if (!(np->features & FE_C10))
                        sval = (sval & ~0xe0) | (fak << 5);
                else {
                        uval = uval & ~(XCLKH_ST|XCLKH_DT|XCLKS_ST|XCLKS_DT);
                        if (fak >= 1) uval |= (XCLKH_ST|XCLKH_DT);
                        if (fak >= 2) uval |= (XCLKS_ST|XCLKS_DT);
                }
        }

        /*
         *  Set the bus width.
         */
        wval = wval & ~EWS;
        if (wide != 0)
                wval |= EWS;

        /*
         *  Set misc. ultra enable bits.
         */
        if (np->features & FE_C10) {
                uval = uval & ~(U3EN|AIPCKEN);
                if (opts)       {
                        assert(np->features & FE_U3EN);
                        uval |= U3EN;
                }
        } else {
                wval = wval & ~ULTRA;
                if (per <= 12)  wval |= ULTRA;
        }

        /*
         *   Stop there if sync parameters are unchanged.
         */
        if (tp->head.sval == sval && 
            tp->head.wval == wval &&
            tp->head.uval == uval)
                return;
        tp->head.sval = sval;
        tp->head.wval = wval;
        tp->head.uval = uval;

        /*
         *  Disable extended Sreq/Sack filtering if per < 50.
         *  Not supported on the C1010.
         */
        if (per < 50 && !(np->features & FE_C10))
                OUTOFFB(np, nc_stest2, EXT);

        /*
         *  set actual value and sync_status
         */
        OUTB(np, nc_sxfer,  tp->head.sval);
        OUTB(np, nc_scntl3, tp->head.wval);

        if (np->features & FE_C10) {
                OUTB(np, nc_scntl4, tp->head.uval);
        }

        /*
         *  patch ALL busy ccbs of this target.
         */
        FOR_EACH_QUEUED_ELEMENT(&np->busy_ccbq, qp) {
                struct sym_ccb *cp;
                cp = sym_que_entry(qp, struct sym_ccb, link_ccbq);
                if (cp->target != target)
                        continue;
                cp->phys.select.sel_scntl3 = tp->head.wval;
                cp->phys.select.sel_sxfer  = tp->head.sval;
                if (np->features & FE_C10) {
                        cp->phys.select.sel_scntl4 = tp->head.uval;
                }
        }
}

/*
 *  We received a WDTR.
 *  Let everything be aware of the changes.
 */
static void sym_setwide(struct sym_hcb *np, int target, u_char wide)
{
        struct sym_tcb *tp = &np->target[target];
        struct scsi_target *starget = tp->starget;

        if (spi_width(starget) == wide)
                return;

        sym_settrans(np, target, 0, 0, 0, wide, 0, 0);

        tp->tgoal.width = wide;
        spi_offset(starget) = 0;
        spi_period(starget) = 0;
        spi_width(starget) = wide;
        spi_iu(starget) = 0;
        spi_dt(starget) = 0;
        spi_qas(starget) = 0;

        if (sym_verbose >= 3)
                spi_display_xfer_agreement(starget);
}

/*
 *  We received a SDTR.
 *  Let everything be aware of the changes.
 */
static void
sym_setsync(struct sym_hcb *np, int target,
            u_char ofs, u_char per, u_char div, u_char fak)
{
        struct sym_tcb *tp = &np->target[target];
        struct scsi_target *starget = tp->starget;
        u_char wide = (tp->head.wval & EWS) ? BUS_16_BIT : BUS_8_BIT;

        sym_settrans(np, target, 0, ofs, per, wide, div, fak);

        spi_period(starget) = per;
        spi_offset(starget) = ofs;
        spi_iu(starget) = spi_dt(starget) = spi_qas(starget) = 0;

        if (!tp->tgoal.dt && !tp->tgoal.iu && !tp->tgoal.qas) {
                tp->tgoal.period = per;
                tp->tgoal.offset = ofs;
                tp->tgoal.check_nego = 0;
        }

        spi_display_xfer_agreement(starget);
}

/*
 *  We received a PPR.
 *  Let everything be aware of the changes.
 */
static void 
sym_setpprot(struct sym_hcb *np, int target, u_char opts, u_char ofs,
             u_char per, u_char wide, u_char div, u_char fak)
{
        struct sym_tcb *tp = &np->target[target];
        struct scsi_target *starget = tp->starget;

        sym_settrans(np, target, opts, ofs, per, wide, div, fak);

        spi_width(starget) = tp->tgoal.width = wide;
        spi_period(starget) = tp->tgoal.period = per;
        spi_offset(starget) = tp->tgoal.offset = ofs;
        spi_iu(starget) = tp->tgoal.iu = !!(opts & PPR_OPT_IU);
        spi_dt(starget) = tp->tgoal.dt = !!(opts & PPR_OPT_DT);
        spi_qas(starget) = tp->tgoal.qas = !!(opts & PPR_OPT_QAS);
        tp->tgoal.check_nego = 0;

        spi_display_xfer_agreement(starget);
}

/*
 *  generic recovery from scsi interrupt
 *
 *  The doc says that when the chip gets an SCSI interrupt,
 *  it tries to stop in an orderly fashion, by completing 
 *  an instruction fetch that had started or by flushing 
 *  the DMA fifo for a write to memory that was executing.
 *  Such a fashion is not enough to know if the instruction 
 *  that was just before the current DSP value has been 
 *  executed or not.
 *
 *  There are some small SCRIPTS sections that deal with 
 *  the start queue and the done queue that may break any 
 *  assomption from the C code if we are interrupted 
 *  inside, so we reset if this happens. Btw, since these 
 *  SCRIPTS sections are executed while the SCRIPTS hasn't 
 *  started SCSI operations, it is very unlikely to happen.
 *
 *  All the driver data structures are supposed to be 
 *  allocated from the same 4 GB memory window, so there 
 *  is a 1 to 1 relationship between DSA and driver data 
 *  structures. Since we are careful :) to invalidate the 
 *  DSA when we complete a command or when the SCRIPTS 
 *  pushes a DSA into a queue, we can trust it when it 
 *  points to a CCB.
 */
static void sym_recover_scsi_int (struct sym_hcb *np, u_char hsts)
{
        u32     dsp     = INL(np, nc_dsp);
        u32     dsa     = INL(np, nc_dsa);
        struct sym_ccb *cp      = sym_ccb_from_dsa(np, dsa);

        /*
         *  If we haven't been interrupted inside the SCRIPTS 
         *  critical pathes, we can safely restart the SCRIPTS 
         *  and trust the DSA value if it matches a CCB.
         */
        if ((!(dsp > SCRIPTA_BA(np, getjob_begin) &&
               dsp < SCRIPTA_BA(np, getjob_end) + 1)) &&
            (!(dsp > SCRIPTA_BA(np, ungetjob) &&
               dsp < SCRIPTA_BA(np, reselect) + 1)) &&
            (!(dsp > SCRIPTB_BA(np, sel_for_abort) &&
               dsp < SCRIPTB_BA(np, sel_for_abort_1) + 1)) &&
            (!(dsp > SCRIPTA_BA(np, done) &&
               dsp < SCRIPTA_BA(np, done_end) + 1))) {
                OUTB(np, nc_ctest3, np->rv_ctest3 | CLF); /* clear dma fifo  */
                OUTB(np, nc_stest3, TE|CSF);            /* clear scsi fifo */
                /*
                 *  If we have a CCB, let the SCRIPTS call us back for 
                 *  the handling of the error with SCRATCHA filled with 
                 *  STARTPOS. This way, we will be able to freeze the 
                 *  device queue and requeue awaiting IOs.
                 */
                if (cp) {
                        cp->host_status = hsts;
                        OUTL_DSP(np, SCRIPTA_BA(np, complete_error));
                }
                /*
                 *  Otherwise just restart the SCRIPTS.
                 */
                else {
                        OUTL(np, nc_dsa, 0xffffff);
                        OUTL_DSP(np, SCRIPTA_BA(np, start));
                }
        }
        else
                goto reset_all;

        return;

reset_all:
        sym_start_reset(np);
}

/*
 *  chip exception handler for selection timeout
 */
static void sym_int_sto (struct sym_hcb *np)
{
        u32 dsp = INL(np, nc_dsp);

        if (DEBUG_FLAGS & DEBUG_TINY) printf ("T");

        if (dsp == SCRIPTA_BA(np, wf_sel_done) + 8)
                sym_recover_scsi_int(np, HS_SEL_TIMEOUT);
        else
                sym_start_reset(np);
}

/*
 *  chip exception handler for unexpected disconnect
 */
static void sym_int_udc (struct sym_hcb *np)
{
        printf ("%s: unexpected disconnect\n", sym_name(np));
        sym_recover_scsi_int(np, HS_UNEXPECTED);
}

/*
 *  chip exception handler for SCSI bus mode change
 *
 *  spi2-r12 11.2.3 says a transceiver mode change must 
 *  generate a reset event and a device that detects a reset 
 *  event shall initiate a hard reset. It says also that a
 *  device that detects a mode change shall set data transfer 
 *  mode to eight bit asynchronous, etc...
 *  So, just reinitializing all except chip should be enough.
 */
static void sym_int_sbmc (struct sym_hcb *np)
{
        u_char scsi_mode = INB(np, nc_stest4) & SMODE;

        /*
         *  Notify user.
         */
        printf("%s: SCSI BUS mode change from %s to %s.\n", sym_name(np),
                sym_scsi_bus_mode(np->scsi_mode), sym_scsi_bus_mode(scsi_mode));

        /*
         *  Should suspend command processing for a few seconds and 
         *  reinitialize all except the chip.
         */
        sym_start_up (np, 2);
}

/*
 *  chip exception handler for SCSI parity error.
 *
 *  When the chip detects a SCSI parity error and is 
 *  currently executing a (CH)MOV instruction, it does 
 *  not interrupt immediately, but tries to finish the 
 *  transfer of the current scatter entry before 
 *  interrupting. The following situations may occur:
 *
 *  - The complete scatter entry has been transferred 
 *    without the device having changed phase.
 *    The chip will then interrupt with the DSP pointing 
 *    to the instruction that follows the MOV.
 *
 *  - A phase mismatch occurs before the MOV finished 
 *    and phase errors are to be handled by the C code.
 *    The chip will then interrupt with both PAR and MA 
 *    conditions set.
 *
 *  - A phase mismatch occurs before the MOV finished and 
 *    phase errors are to be handled by SCRIPTS.
 *    The chip will load the DSP with the phase mismatch 
 *    JUMP address and interrupt the host processor.
 */
static void sym_int_par (struct sym_hcb *np, u_short sist)
{
        u_char  hsts    = INB(np, HS_PRT);
        u32     dsp     = INL(np, nc_dsp);
        u32     dbc     = INL(np, nc_dbc);
        u32     dsa     = INL(np, nc_dsa);
        u_char  sbcl    = INB(np, nc_sbcl);
        u_char  cmd     = dbc >> 24;
        int phase       = cmd & 7;
        struct sym_ccb *cp      = sym_ccb_from_dsa(np, dsa);

        printf("%s: SCSI parity error detected: SCR1=%d DBC=%x SBCL=%x\n",
                sym_name(np), hsts, dbc, sbcl);

        /*
         *  Check that the chip is connected to the SCSI BUS.
         */
        if (!(INB(np, nc_scntl1) & ISCON)) {
                sym_recover_scsi_int(np, HS_UNEXPECTED);
                return;
        }

        /*
         *  If the nexus is not clearly identified, reset the bus.
         *  We will try to do better later.
         */
        if (!cp)
                goto reset_all;

        /*
         *  Check instruction was a MOV, direction was INPUT and 
         *  ATN is asserted.
         */
        if ((cmd & 0xc0) || !(phase & 1) || !(sbcl & 0x8))
                goto reset_all;

        /*
         *  Keep track of the parity error.
         */
        OUTONB(np, HF_PRT, HF_EXT_ERR);
        cp->xerr_status |= XE_PARITY_ERR;

        /*
         *  Prepare the message to send to the device.
         */
        np->msgout[0] = (phase == 7) ? M_PARITY : M_ID_ERROR;

        /*
         *  If the old phase was DATA IN phase, we have to deal with
         *  the 3 situations described above.
         *  For other input phases (MSG IN and STATUS), the device 
         *  must resend the whole thing that failed parity checking 
         *  or signal error. So, jumping to dispatcher should be OK.
         */
        if (phase == 1 || phase == 5) {
                /* Phase mismatch handled by SCRIPTS */
                if (dsp == SCRIPTB_BA(np, pm_handle))
                        OUTL_DSP(np, dsp);
                /* Phase mismatch handled by the C code */
                else if (sist & MA)
                        sym_int_ma (np);
                /* No phase mismatch occurred */
                else {
                        sym_set_script_dp (np, cp, dsp);
                        OUTL_DSP(np, SCRIPTA_BA(np, dispatch));
                }
        }
        else if (phase == 7)    /* We definitely cannot handle parity errors */
#if 1                           /* in message-in phase due to the relection  */
                goto reset_all; /* path and various message anticipations.   */
#else
                OUTL_DSP(np, SCRIPTA_BA(np, clrack));
#endif
        else
                OUTL_DSP(np, SCRIPTA_BA(np, dispatch));
        return;

reset_all:
        sym_start_reset(np);
        return;
}

/*
 *  chip exception handler for phase errors.
 *
 *  We have to construct a new transfer descriptor,
 *  to transfer the rest of the current block.
 */
static void sym_int_ma (struct sym_hcb *np)
{
        u32     dbc;
        u32     rest;
        u32     dsp;
        u32     dsa;
        u32     nxtdsp;
        u32     *vdsp;
        u32     oadr, olen;
        u32     *tblp;
        u32     newcmd;
        u_int   delta;
        u_char  cmd;
        u_char  hflags, hflags0;
        struct  sym_pmc *pm;
        struct sym_ccb *cp;

        dsp     = INL(np, nc_dsp);
        dbc     = INL(np, nc_dbc);
        dsa     = INL(np, nc_dsa);

        cmd     = dbc >> 24;
        rest    = dbc & 0xffffff;
        delta   = 0;

        /*
         *  locate matching cp if any.
         */
        cp = sym_ccb_from_dsa(np, dsa);

        /*
         *  Donnot take into account dma fifo and various buffers in 
         *  INPUT phase since the chip flushes everything before 
         *  raising the MA interrupt for interrupted INPUT phases.
         *  For DATA IN phase, we will check for the SWIDE later.
         */
        if ((cmd & 7) != 1 && (cmd & 7) != 5) {
                u_char ss0, ss2;

                if (np->features & FE_DFBC)
                        delta = INW(np, nc_dfbc);
                else {
                        u32 dfifo;

                        /*
                         * Read DFIFO, CTEST[4-6] using 1 PCI bus ownership.
                         */
                        dfifo = INL(np, nc_dfifo);

                        /*
                         *  Calculate remaining bytes in DMA fifo.
                         *  (CTEST5 = dfifo >> 16)
                         */
                        if (dfifo & (DFS << 16))
                                delta = ((((dfifo >> 8) & 0x300) |
                                          (dfifo & 0xff)) - rest) & 0x3ff;
                        else
                                delta = ((dfifo & 0xff) - rest) & 0x7f;
                }

                /*
                 *  The data in the dma fifo has not been transfered to
                 *  the target -> add the amount to the rest
                 *  and clear the data.
                 *  Check the sstat2 register in case of wide transfer.
                 */
                rest += delta;
                ss0  = INB(np, nc_sstat0);
                if (ss0 & OLF) rest++;
                if (!(np->features & FE_C10))
                        if (ss0 & ORF) rest++;
                if (cp && (cp->phys.select.sel_scntl3 & EWS)) {
                        ss2 = INB(np, nc_sstat2);
                        if (ss2 & OLF1) rest++;
                        if (!(np->features & FE_C10))
                                if (ss2 & ORF1) rest++;
                }

                /*
                 *  Clear fifos.
                 */
                OUTB(np, nc_ctest3, np->rv_ctest3 | CLF);       /* dma fifo  */
                OUTB(np, nc_stest3, TE|CSF);            /* scsi fifo */
        }

        /*
         *  log the information
         */
        if (DEBUG_FLAGS & (DEBUG_TINY|DEBUG_PHASE))
                printf ("P%x%x RL=%d D=%d ", cmd&7, INB(np, nc_sbcl)&7,
                        (unsigned) rest, (unsigned) delta);

        /*
         *  try to find the interrupted script command,
         *  and the address at which to continue.
         */
        vdsp    = NULL;
        nxtdsp  = 0;
        if      (dsp >  np->scripta_ba &&
                 dsp <= np->scripta_ba + np->scripta_sz) {
                vdsp = (u32 *)((char*)np->scripta0 + (dsp-np->scripta_ba-8));
                nxtdsp = dsp;
        }
        else if (dsp >  np->scriptb_ba &&
                 dsp <= np->scriptb_ba + np->scriptb_sz) {
                vdsp = (u32 *)((char*)np->scriptb0 + (dsp-np->scriptb_ba-8));
                nxtdsp = dsp;
        }

        /*
         *  log the information
         */
        if (DEBUG_FLAGS & DEBUG_PHASE) {
                printf ("\nCP=%p DSP=%x NXT=%x VDSP=%p CMD=%x ",
                        cp, (unsigned)dsp, (unsigned)nxtdsp, vdsp, cmd);
        }

        if (!vdsp) {
                printf ("%s: interrupted SCRIPT address not found.\n", 
                        sym_name (np));
                goto reset_all;
        }

        if (!cp) {
                printf ("%s: SCSI phase error fixup: CCB already dequeued.\n", 
                        sym_name (np));
                goto reset_all;
        }

        /*
         *  get old startaddress and old length.
         */
        oadr = scr_to_cpu(vdsp[1]);

        if (cmd & 0x10) {       /* Table indirect */
                tblp = (u32 *) ((char*) &cp->phys + oadr);
                olen = scr_to_cpu(tblp[0]);
                oadr = scr_to_cpu(tblp[1]);
        } else {
                tblp = (u32 *) 0;
                olen = scr_to_cpu(vdsp[0]) & 0xffffff;
        }

        if (DEBUG_FLAGS & DEBUG_PHASE) {
                printf ("OCMD=%x\nTBLP=%p OLEN=%x OADR=%x\n",
                        (unsigned) (scr_to_cpu(vdsp[0]) >> 24),
                        tblp,
                        (unsigned) olen,
                        (unsigned) oadr);
        }

        /*
         *  check cmd against assumed interrupted script command.
         *  If dt data phase, the MOVE instruction hasn't bit 4 of 
         *  the phase.
         */
        if (((cmd & 2) ? cmd : (cmd & ~4)) != (scr_to_cpu(vdsp[0]) >> 24)) {
                sym_print_addr(cp->cmd,
                        "internal error: cmd=%02x != %02x=(vdsp[0] >> 24)\n",
                        cmd, scr_to_cpu(vdsp[0]) >> 24);

                goto reset_all;
        }

        /*
         *  if old phase not dataphase, leave here.
         */
        if (cmd & 2) {
                sym_print_addr(cp->cmd,
                        "phase change %x-%x %d@%08x resid=%d.\n",
                        cmd&7, INB(np, nc_sbcl)&7, (unsigned)olen,
                        (unsigned)oadr, (unsigned)rest);
                goto unexpected_phase;
        }

        /*
         *  Choose the correct PM save area.
         *
         *  Look at the PM_SAVE SCRIPT if you want to understand 
         *  this stuff. The equivalent code is implemented in 
         *  SCRIPTS for the 895A, 896 and 1010 that are able to 
         *  handle PM from the SCRIPTS processor.
         */
        hflags0 = INB(np, HF_PRT);
        hflags = hflags0;

        if (hflags & (HF_IN_PM0 | HF_IN_PM1 | HF_DP_SAVED)) {
                if (hflags & HF_IN_PM0)
                        nxtdsp = scr_to_cpu(cp->phys.pm0.ret);
                else if (hflags & HF_IN_PM1)
                        nxtdsp = scr_to_cpu(cp->phys.pm1.ret);

                if (hflags & HF_DP_SAVED)
                        hflags ^= HF_ACT_PM;
        }

        if (!(hflags & HF_ACT_PM)) {
                pm = &cp->phys.pm0;
                newcmd = SCRIPTA_BA(np, pm0_data);
        }
        else {
                pm = &cp->phys.pm1;
                newcmd = SCRIPTA_BA(np, pm1_data);
        }

        hflags &= ~(HF_IN_PM0 | HF_IN_PM1 | HF_DP_SAVED);
        if (hflags != hflags0)
                OUTB(np, HF_PRT, hflags);

        /*
         *  fillin the phase mismatch context
         */
        pm->sg.addr = cpu_to_scr(oadr + olen - rest);
        pm->sg.size = cpu_to_scr(rest);
        pm->ret     = cpu_to_scr(nxtdsp);

        /*
         *  If we have a SWIDE,
         *  - prepare the address to write the SWIDE from SCRIPTS,
         *  - compute the SCRIPTS address to restart from,
         *  - move current data pointer context by one byte.
         */
        nxtdsp = SCRIPTA_BA(np, dispatch);
        if ((cmd & 7) == 1 && cp && (cp->phys.select.sel_scntl3 & EWS) &&
            (INB(np, nc_scntl2) & WSR)) {
                u32 tmp;

                /*
                 *  Set up the table indirect for the MOVE
                 *  of the residual byte and adjust the data 
                 *  pointer context.
                 */
                tmp = scr_to_cpu(pm->sg.addr);
                cp->phys.wresid.addr = cpu_to_scr(tmp);
                pm->sg.addr = cpu_to_scr(tmp + 1);
                tmp = scr_to_cpu(pm->sg.size);
                cp->phys.wresid.size = cpu_to_scr((tmp&0xff000000) | 1);
                pm->sg.size = cpu_to_scr(tmp - 1);

                /*
                 *  If only the residual byte is to be moved, 
                 *  no PM context is needed.
                 */
                if ((tmp&0xffffff) == 1)
                        newcmd = pm->ret;

                /*
                 *  Prepare the address of SCRIPTS that will 
                 *  move the residual byte to memory.
                 */
                nxtdsp = SCRIPTB_BA(np, wsr_ma_helper);
        }

        if (DEBUG_FLAGS & DEBUG_PHASE) {
                sym_print_addr(cp->cmd, "PM %x %x %x / %x %x %x.\n",
                        hflags0, hflags, newcmd,
                        (unsigned)scr_to_cpu(pm->sg.addr),
                        (unsigned)scr_to_cpu(pm->sg.size),
                        (unsigned)scr_to_cpu(pm->ret));
        }

        /*
         *  Restart the SCRIPTS processor.
         */
        sym_set_script_dp (np, cp, newcmd);
        OUTL_DSP(np, nxtdsp);
        return;

        /*
         *  Unexpected phase changes that occurs when the current phase 
         *  is not a DATA IN or DATA OUT phase are due to error conditions.
         *  Such event may only happen when the SCRIPTS is using a 
         *  multibyte SCSI MOVE.
         *
         *  Phase change                Some possible cause
         *
         *  COMMAND  --> MSG IN SCSI parity error detected by target.
         *  COMMAND  --> STATUS Bad command or refused by target.
         *  MSG OUT  --> MSG IN     Message rejected by target.
         *  MSG OUT  --> COMMAND    Bogus target that discards extended
         *                      negotiation messages.
         *
         *  The code below does not care of the new phase and so 
         *  trusts the target. Why to annoy it ?
         *  If the interrupted phase is COMMAND phase, we restart at
         *  dispatcher.
         *  If a target does not get all the messages after selection, 
         *  the code assumes blindly that the target discards extended 
         *  messages and clears the negotiation status.
         *  If the target does not want all our response to negotiation,
         *  we force a SIR_NEGO_PROTO interrupt (it is a hack that avoids 
         *  bloat for such a should_not_happen situation).
         *  In all other situation, we reset the BUS.
         *  Are these assumptions reasonnable ? (Wait and see ...)
         */
unexpected_phase:
        dsp -= 8;
        nxtdsp = 0;

        switch (cmd & 7) {
        case 2: /* COMMAND phase */
                nxtdsp = SCRIPTA_BA(np, dispatch);
                break;
#if 0
        case 3: /* STATUS  phase */
                nxtdsp = SCRIPTA_BA(np, dispatch);
                break;
#endif
        case 6: /* MSG OUT phase */
                /*
                 *  If the device may want to use untagged when we want 
                 *  tagged, we prepare an IDENTIFY without disc. granted, 
                 *  since we will not be able to handle reselect.
                 *  Otherwise, we just don't care.
                 */
                if      (dsp == SCRIPTA_BA(np, send_ident)) {
                        if (cp->tag != NO_TAG && olen - rest <= 3) {
                                cp->host_status = HS_BUSY;
                                np->msgout[0] = IDENTIFY(0, cp->lun);
                                nxtdsp = SCRIPTB_BA(np, ident_break_atn);
                        }
                        else
                                nxtdsp = SCRIPTB_BA(np, ident_break);
                }
                else if (dsp == SCRIPTB_BA(np, send_wdtr) ||
                         dsp == SCRIPTB_BA(np, send_sdtr) ||
                         dsp == SCRIPTB_BA(np, send_ppr)) {
                        nxtdsp = SCRIPTB_BA(np, nego_bad_phase);
                        if (dsp == SCRIPTB_BA(np, send_ppr)) {
                                struct scsi_device *dev = cp->cmd->device;
                                dev->ppr = 0;
                        }
                }
                break;
#if 0
        case 7: /* MSG IN  phase */
                nxtdsp = SCRIPTA_BA(np, clrack);
                break;
#endif
        }

        if (nxtdsp) {
                OUTL_DSP(np, nxtdsp);
                return;
        }

reset_all:
        sym_start_reset(np);
}

/*
 *  chip interrupt handler
 *
 *  In normal situations, interrupt conditions occur one at 
 *  a time. But when something bad happens on the SCSI BUS, 
 *  the chip may raise several interrupt flags before 
 *  stopping and interrupting the CPU. The additionnal 
 *  interrupt flags are stacked in some extra registers 
 *  after the SIP and/or DIP flag has been raised in the 
 *  ISTAT. After the CPU has read the interrupt condition 
 *  flag from SIST or DSTAT, the chip unstacks the other 
 *  interrupt flags and sets the corresponding bits in 
 *  SIST or DSTAT. Since the chip starts stacking once the 
 *  SIP or DIP flag is set, there is a small window of time 
 *  where the stacking does not occur.
 *
 *  Typically, multiple interrupt conditions may happen in 
 *  the following situations:
 *
 *  - SCSI parity error + Phase mismatch  (PAR|MA)
 *    When an parity error is detected in input phase 
 *    and the device switches to msg-in phase inside a 
 *    block MOV.
 *  - SCSI parity error + Unexpected disconnect (PAR|UDC)
 *    When a stupid device does not want to handle the 
 *    recovery of an SCSI parity error.
 *  - Some combinations of STO, PAR, UDC, ...
 *    When using non compliant SCSI stuff, when user is 
 *    doing non compliant hot tampering on the BUS, when 
 *    something really bad happens to a device, etc ...
 *
 *  The heuristic suggested by SYMBIOS to handle 
 *  multiple interrupts is to try unstacking all 
 *  interrupts conditions and to handle them on some 
 *  priority based on error severity.
 *  This will work when the unstacking has been 
 *  successful, but we cannot be 100 % sure of that, 
 *  since the CPU may have been faster to unstack than 
 *  the chip is able to stack. Hmmm ... But it seems that 
 *  such a situation is very unlikely to happen.
 *
 *  If this happen, for example STO caught by the CPU 
 *  then UDC happenning before the CPU have restarted 
 *  the SCRIPTS, the driver may wrongly complete the 
 *  same command on UDC, since the SCRIPTS didn't restart 
 *  and the DSA still points to the same command.
 *  We avoid this situation by setting the DSA to an 
 *  invalid value when the CCB is completed and before 
 *  restarting the SCRIPTS.
 *
 *  Another issue is that we need some section of our 
 *  recovery procedures to be somehow uninterruptible but 
 *  the SCRIPTS processor does not provides such a 
 *  feature. For this reason, we handle recovery preferently 
 *  from the C code and check against some SCRIPTS critical 
 *  sections from the C code.
 *
 *  Hopefully, the interrupt handling of the driver is now 
 *  able to resist to weird BUS error conditions, but donnot 
 *  ask me for any guarantee that it will never fail. :-)
 *  Use at your own decision and risk.
 */

void sym_interrupt (struct sym_hcb *np)
{
        u_char  istat, istatc;
        u_char  dstat;
        u_short sist;

        /*
         *  interrupt on the fly ?
         *  (SCRIPTS may still be running)
         *
         *  A `dummy read' is needed to ensure that the 
         *  clear of the INTF flag reaches the device 
         *  and that posted writes are flushed to memory
         *  before the scanning of the DONE queue.
         *  Note that SCRIPTS also (dummy) read to memory 
         *  prior to deliver the INTF interrupt condition.
         */
        istat = INB(np, nc_istat);
        if (istat & INTF) {
                OUTB(np, nc_istat, (istat & SIGP) | INTF | np->istat_sem);
                istat = INB(np, nc_istat);              /* DUMMY READ */
                if (DEBUG_FLAGS & DEBUG_TINY) printf ("F ");
                sym_wakeup_done(np);
        }

        if (!(istat & (SIP|DIP)))
                return;

#if 0   /* We should never get this one */
        if (istat & CABRT)
                OUTB(np, nc_istat, CABRT);
#endif

        /*
         *  PAR and MA interrupts may occur at the same time,
         *  and we need to know of both in order to handle 
         *  this situation properly. We try to unstack SCSI 
         *  interrupts for that reason. BTW, I dislike a LOT 
         *  such a loop inside the interrupt routine.
         *  Even if DMA interrupt stacking is very unlikely to 
         *  happen, we also try unstacking these ones, since 
         *  this has no performance impact.
         */
        sist    = 0;
        dstat   = 0;
        istatc  = istat;
        do {
                if (istatc & SIP)
                        sist  |= INW(np, nc_sist);
                if (istatc & DIP)
                        dstat |= INB(np, nc_dstat);
                istatc = INB(np, nc_istat);
                istat |= istatc;
        } while (istatc & (SIP|DIP));

        if (DEBUG_FLAGS & DEBUG_TINY)
                printf ("<%d|%x:%x|%x:%x>",
                        (int)INB(np, nc_scr0),
                        dstat,sist,
                        (unsigned)INL(np, nc_dsp),
                        (unsigned)INL(np, nc_dbc));
        /*
         *  On paper, a memory read barrier may be needed here to 
         *  prevent out of order LOADs by the CPU from having 
         *  prefetched stale data prior to DMA having occurred.
         *  And since we are paranoid ... :)
         */
        MEMORY_READ_BARRIER();

        /*
         *  First, interrupts we want to service cleanly.
         *
         *  Phase mismatch (MA) is the most frequent interrupt 
         *  for chip earlier than the 896 and so we have to service 
         *  it as quickly as possible.
         *  A SCSI parity error (PAR) may be combined with a phase 
         *  mismatch condition (MA).
         *  Programmed interrupts (SIR) are used to call the C code 
         *  from SCRIPTS.
         *  The single step interrupt (SSI) is not used in this 
         *  driver.
         */
        if (!(sist  & (STO|GEN|HTH|SGE|UDC|SBMC|RST)) &&
            !(dstat & (MDPE|BF|ABRT|IID))) {
                if      (sist & PAR)    sym_int_par (np, sist);
                else if (sist & MA)     sym_int_ma (np);
                else if (dstat & SIR)   sym_int_sir (np);
                else if (dstat & SSI)   OUTONB_STD();
                else                    goto unknown_int;
                return;
        }

        /*
         *  Now, interrupts that donnot happen in normal 
         *  situations and that we may need to recover from.
         *
         *  On SCSI RESET (RST), we reset everything.
         *  On SCSI BUS MODE CHANGE (SBMC), we complete all 
         *  active CCBs with RESET status, prepare all devices 
         *  for negotiating again and restart the SCRIPTS.
         *  On STO and UDC, we complete the CCB with the corres- 
         *  ponding status and restart the SCRIPTS.
         */
        if (sist & RST) {
                printf("%s: SCSI BUS reset detected.\n", sym_name(np));
                sym_start_up (np, 1);
                return;
        }

        OUTB(np, nc_ctest3, np->rv_ctest3 | CLF);       /* clear dma fifo  */
        OUTB(np, nc_stest3, TE|CSF);            /* clear scsi fifo */

        if (!(sist  & (GEN|HTH|SGE)) &&
            !(dstat & (MDPE|BF|ABRT|IID))) {
                if      (sist & SBMC)   sym_int_sbmc (np);
                else if (sist & STO)    sym_int_sto (np);
                else if (sist & UDC)    sym_int_udc (np);
                else                    goto unknown_int;
                return;
        }

        /*
         *  Now, interrupts we are not able to recover cleanly.
         *
         *  Log message for hard errors.
         *  Reset everything.
         */

        sym_log_hard_error(np, sist, dstat);

        if ((sist & (GEN|HTH|SGE)) ||
                (dstat & (MDPE|BF|ABRT|IID))) {
                sym_start_reset(np);
                return;
        }

unknown_int:
        /*
         *  We just miss the cause of the interrupt. :(
         *  Print a message. The timeout will do the real work.
         */
        printf( "%s: unknown interrupt(s) ignored, "
                "ISTAT=0x%x DSTAT=0x%x SIST=0x%x\n",
                sym_name(np), istat, dstat, sist);
}

/*
 *  Dequeue from the START queue all CCBs that match 
 *  a given target/lun/task condition (-1 means all),
 *  and move them from the BUSY queue to the COMP queue 
 *  with DID_SOFT_ERROR status condition.
 *  This function is used during error handling/recovery.
 *  It is called with SCRIPTS not running.
 */
static int 
sym_dequeue_from_squeue(struct sym_hcb *np, int i, int target, int lun, int task)
{
        int j;
        struct sym_ccb *cp;

        /*
         *  Make sure the starting index is within range.
         */
        assert((i >= 0) && (i < 2*MAX_QUEUE));

        /*
         *  Walk until end of START queue and dequeue every job 
         *  that matches the target/lun/task condition.
         */
        j = i;
        while (i != np->squeueput) {
                cp = sym_ccb_from_dsa(np, scr_to_cpu(np->squeue[i]));
                assert(cp);
#ifdef SYM_CONF_IARB_SUPPORT
                /* Forget hints for IARB, they may be no longer relevant */
                cp->host_flags &= ~HF_HINT_IARB;
#endif
                if ((target == -1 || cp->target == target) &&
                    (lun    == -1 || cp->lun    == lun)    &&
                    (task   == -1 || cp->tag    == task)) {
                        sym_set_cam_status(cp->cmd, DID_SOFT_ERROR);
                        sym_remque(&cp->link_ccbq);
                        sym_insque_tail(&cp->link_ccbq, &np->comp_ccbq);
                }
                else {
                        if (i != j)
                                np->squeue[j] = np->squeue[i];
                        if ((j += 2) >= MAX_QUEUE*2) j = 0;
                }
                if ((i += 2) >= MAX_QUEUE*2) i = 0;
        }
        if (i != j)             /* Copy back the idle task if needed */
                np->squeue[j] = np->squeue[i];
        np->squeueput = j;      /* Update our current start queue pointer */

        return (i - j) / 2;
}

/*
 *  chip handler for bad SCSI status condition
 *
 *  In case of bad SCSI status, we unqueue all the tasks 
 *  currently queued to the controller but not yet started 
 *  and then restart the SCRIPTS processor immediately.
 *
 *  QUEUE FULL and BUSY conditions are handled the same way.
 *  Basically all the not yet started tasks are requeued in 
 *  device queue and the queue is frozen until a completion.
 *
 *  For CHECK CONDITION and COMMAND TERMINATED status, we use 
 *  the CCB of the failed command to prepare a REQUEST SENSE 
 *  SCSI command and queue it to the controller queue.
 *
 *  SCRATCHA is assumed to have been loaded with STARTPOS 
 *  before the SCRIPTS called the C code.
 */
static void sym_sir_bad_scsi_status(struct sym_hcb *np, int num, struct sym_ccb *cp)
{
        u32             startp;
        u_char          s_status = cp->ssss_status;
        u_char          h_flags  = cp->host_flags;
        int             msglen;
        int             i;

        /*
         *  Compute the index of the next job to start from SCRIPTS.
         */
        i = (INL(np, nc_scratcha) - np->squeue_ba) / 4;

        /*
         *  The last CCB queued used for IARB hint may be 
         *  no longer relevant. Forget it.
         */
#ifdef SYM_CONF_IARB_SUPPORT
        if (np->last_cp)
                np->last_cp = 0;
#endif

        /*
         *  Now deal with the SCSI status.
         */
        switch(s_status) {
        case S_BUSY:
        case S_QUEUE_FULL:
                if (sym_verbose >= 2) {
                        sym_print_addr(cp->cmd, "%s\n",
                                s_status == S_BUSY ? "BUSY" : "QUEUE FULL\n");
                }
        default:        /* S_INT, S_INT_COND_MET, S_CONFLICT */
                sym_complete_error (np, cp);
                break;
        case S_TERMINATED:
        case S_CHECK_COND:
                /*
                 *  If we get an SCSI error when requesting sense, give up.
                 */
                if (h_flags & HF_SENSE) {
                        sym_complete_error (np, cp);
                        break;
                }

                /*
                 *  Dequeue all queued CCBs for that device not yet started,
                 *  and restart the SCRIPTS processor immediately.
                 */
                sym_dequeue_from_squeue(np, i, cp->target, cp->lun, -1);
                OUTL_DSP(np, SCRIPTA_BA(np, start));

                /*
                 *  Save some info of the actual IO.
                 *  Compute the data residual.
                 */
                cp->sv_scsi_status = cp->ssss_status;
                cp->sv_xerr_status = cp->xerr_status;
                cp->sv_resid = sym_compute_residual(np, cp);

                /*
                 *  Prepare all needed data structures for 
                 *  requesting sense data.
                 */

                cp->scsi_smsg2[0] = IDENTIFY(0, cp->lun);
                msglen = 1;

                /*
                 *  If we are currently using anything different from 
                 *  async. 8 bit data transfers with that target,
                 *  start a negotiation, since the device may want 
                 *  to report us a UNIT ATTENTION condition due to 
                 *  a cause we currently ignore, and we donnot want 
                 *  to be stuck with WIDE and/or SYNC data transfer.
                 *
                 *  cp->nego_status is filled by sym_prepare_nego().
                 */
                cp->nego_status = 0;
                msglen += sym_prepare_nego(np, cp, &cp->scsi_smsg2[msglen]);
                /*
                 *  Message table indirect structure.
                 */
                cp->phys.smsg.addr      = CCB_BA(cp, scsi_smsg2);
                cp->phys.smsg.size      = cpu_to_scr(msglen);

                /*
                 *  sense command
                 */
                cp->phys.cmd.addr       = CCB_BA(cp, sensecmd);
                cp->phys.cmd.size       = cpu_to_scr(6);

                /*
                 *  patch requested size into sense command
                 */
                cp->sensecmd[0]         = REQUEST_SENSE;
                cp->sensecmd[1]         = 0;
                if (cp->cmd->device->scsi_level <= SCSI_2 && cp->lun <= 7)
                        cp->sensecmd[1] = cp->lun << 5;
                cp->sensecmd[4]         = SYM_SNS_BBUF_LEN;
                cp->data_len            = SYM_SNS_BBUF_LEN;

                /*
                 *  sense data
                 */
                memset(cp->sns_bbuf, 0, SYM_SNS_BBUF_LEN);
                cp->phys.sense.addr     = CCB_BA(cp, sns_bbuf);
                cp->phys.sense.size     = cpu_to_scr(SYM_SNS_BBUF_LEN);

                /*
                 *  requeue the command.
                 */
                startp = SCRIPTB_BA(np, sdata_in);

                cp->phys.head.savep     = cpu_to_scr(startp);
                cp->phys.head.lastp     = cpu_to_scr(startp);
                cp->startp              = cpu_to_scr(startp);
                cp->goalp               = cpu_to_scr(startp + 16);

                cp->host_xflags = 0;
                cp->host_status = cp->nego_status ? HS_NEGOTIATE : HS_BUSY;
                cp->ssss_status = S_ILLEGAL;
                cp->host_flags  = (HF_SENSE|HF_DATA_IN);
                cp->xerr_status = 0;
                cp->extra_bytes = 0;

                cp->phys.head.go.start = cpu_to_scr(SCRIPTA_BA(np, select));

                /*
                 *  Requeue the command.
                 */
                sym_put_start_queue(np, cp);

                /*
                 *  Give back to upper layer everything we have dequeued.
                 */
                sym_flush_comp_queue(np, 0);
                break;
        }
}

/*
 *  After a device has accepted some management message 
 *  as BUS DEVICE RESET, ABORT TASK, etc ..., or when 
 *  a device signals a UNIT ATTENTION condition, some 
 *  tasks are thrown away by the device. We are required 
 *  to reflect that on our tasks list since the device 
 *  will never complete these tasks.
 *
 *  This function move from the BUSY queue to the COMP 
 *  queue all disconnected CCBs for a given target that 
 *  match the following criteria:
 *  - lun=-1  means any logical UNIT otherwise a given one.
 *  - task=-1 means any task, otherwise a given one.
 */
int sym_clear_tasks(struct sym_hcb *np, int cam_status, int target, int lun, int task)
{
        SYM_QUEHEAD qtmp, *qp;
        int i = 0;
        struct sym_ccb *cp;

        /*
         *  Move the entire BUSY queue to our temporary queue.
         */
        sym_que_init(&qtmp);
        sym_que_splice(&np->busy_ccbq, &qtmp);
        sym_que_init(&np->busy_ccbq);

        /*
         *  Put all CCBs that matches our criteria into 
         *  the COMP queue and put back other ones into 
         *  the BUSY queue.
         */
        while ((qp = sym_remque_head(&qtmp)) != 0) {
                struct scsi_cmnd *cmd;
                cp = sym_que_entry(qp, struct sym_ccb, link_ccbq);
                cmd = cp->cmd;
                if (cp->host_status != HS_DISCONNECT ||
                    cp->target != target             ||
                    (lun  != -1 && cp->lun != lun)   ||
                    (task != -1 && 
                        (cp->tag != NO_TAG && cp->scsi_smsg[2] != task))) {
                        sym_insque_tail(&cp->link_ccbq, &np->busy_ccbq);
                        continue;
                }
                sym_insque_tail(&cp->link_ccbq, &np->comp_ccbq);

                /* Preserve the software timeout condition */
                if (sym_get_cam_status(cmd) != DID_TIME_OUT)
                        sym_set_cam_status(cmd, cam_status);
                ++i;
#if 0
printf("XXXX TASK @%p CLEARED\n", cp);
#endif
        }
        return i;
}

/*
 *  chip handler for TASKS recovery
 *
 *  We cannot safely abort a command, while the SCRIPTS 
 *  processor is running, since we just would be in race 
 *  with it.
 *
 *  As long as we have tasks to abort, we keep the SEM 
 *  bit set in the ISTAT. When this bit is set, the 
 *  SCRIPTS processor interrupts (SIR_SCRIPT_STOPPED) 
 *  each time it enters the scheduler.
 *
 *  If we have to reset a target, clear tasks of a unit,
 *  or to perform the abort of a disconnected job, we 
 *  restart the SCRIPTS for selecting the target. Once 
 *  selected, the SCRIPTS interrupts (SIR_TARGET_SELECTED).
 *  If it loses arbitration, the SCRIPTS will interrupt again 
 *  the next time it will enter its scheduler, and so on ...
 *
 *  On SIR_TARGET_SELECTED, we scan for the more 
 *  appropriate thing to do:
 *
 *  - If nothing, we just sent a M_ABORT message to the 
 *    target to get rid of the useless SCSI bus ownership.
 *    According to the specs, no tasks shall be affected.
 *  - If the target is to be reset, we send it a M_RESET 
 *    message.
 *  - If a logical UNIT is to be cleared , we send the 
 *    IDENTIFY(lun) + M_ABORT.
 *  - If an untagged task is to be aborted, we send the 
 *    IDENTIFY(lun) + M_ABORT.
 *  - If a tagged task is to be aborted, we send the 
 *    IDENTIFY(lun) + task attributes + M_ABORT_TAG.
 *
 *  Once our 'kiss of death' :) message has been accepted 
 *  by the target, the SCRIPTS interrupts again 
 *  (SIR_ABORT_SENT). On this interrupt, we complete 
 *  all the CCBs that should have been aborted by the 
 *  target according to our message.
 */
static void sym_sir_task_recovery(struct sym_hcb *np, int num)
{
        SYM_QUEHEAD *qp;
        struct sym_ccb *cp;
        struct sym_tcb *tp = NULL; /* gcc isn't quite smart enough yet */
        struct scsi_target *starget;
        int target=-1, lun=-1, task;
        int i, k;

        switch(num) {
        /*
         *  The SCRIPTS processor stopped before starting
         *  the next command in order to allow us to perform 
         *  some task recovery.
         */
        case SIR_SCRIPT_STOPPED:
                /*
                 *  Do we have any target to reset or unit to clear ?
                 */
                for (i = 0 ; i < SYM_CONF_MAX_TARGET ; i++) {
                        tp = &np->target[i];
                        if (tp->to_reset || 
                            (tp->lun0p && tp->lun0p->to_clear)) {
                                target = i;
                                break;
                        }
                        if (!tp->lunmp)
                                continue;
                        for (k = 1 ; k < SYM_CONF_MAX_LUN ; k++) {
                                if (tp->lunmp[k] && tp->lunmp[k]->to_clear) {
                                        target  = i;
                                        break;
                                }
                        }
                        if (target != -1)
                                break;
                }

                /*
                 *  If not, walk the busy queue for any 
                 *  disconnected CCB to be aborted.
                 */
                if (target == -1) {
                        FOR_EACH_QUEUED_ELEMENT(&np->busy_ccbq, qp) {
                                cp = sym_que_entry(qp,struct sym_ccb,link_ccbq);
                                if (cp->host_status != HS_DISCONNECT)
                                        continue;
                                if (cp->to_abort) {
                                        target = cp->target;
                                        break;
                                }
                        }
                }

                /*
                 *  If some target is to be selected, 
                 *  prepare and start the selection.
                 */
                if (target != -1) {
                        tp = &np->target[target];
                        np->abrt_sel.sel_id     = target;
                        np->abrt_sel.sel_scntl3 = tp->head.wval;
                        np->abrt_sel.sel_sxfer  = tp->head.sval;
                        OUTL(np, nc_dsa, np->hcb_ba);
                        OUTL_DSP(np, SCRIPTB_BA(np, sel_for_abort));
                        return;
                }

                /*
                 *  Now look for a CCB to abort that haven't started yet.
                 *  Btw, the SCRIPTS processor is still stopped, so 
                 *  we are not in race.
                 */
                i = 0;
                cp = NULL;
                FOR_EACH_QUEUED_ELEMENT(&np->busy_ccbq, qp) {
                        cp = sym_que_entry(qp, struct sym_ccb, link_ccbq);
                        if (cp->host_status != HS_BUSY &&
                            cp->host_status != HS_NEGOTIATE)
                                continue;
                        if (!cp->to_abort)
                                continue;
#ifdef SYM_CONF_IARB_SUPPORT
                        /*
                         *    If we are using IMMEDIATE ARBITRATION, we donnot 
                         *    want to cancel the last queued CCB, since the 
                         *    SCRIPTS may have anticipated the selection.
                         */
                        if (cp == np->last_cp) {
                                cp->to_abort = 0;
                                continue;
                        }
#endif
                        i = 1;  /* Means we have found some */
                        break;
                }
                if (!i) {
                        /*
                         *  We are done, so we donnot need 
                         *  to synchronize with the SCRIPTS anylonger.
                         *  Remove the SEM flag from the ISTAT.
                         */
                        np->istat_sem = 0;
                        OUTB(np, nc_istat, SIGP);
                        break;
                }
                /*
                 *  Compute index of next position in the start 
                 *  queue the SCRIPTS intends to start and dequeue 
                 *  all CCBs for that device that haven't been started.
                 */
                i = (INL(np, nc_scratcha) - np->squeue_ba) / 4;
                i = sym_dequeue_from_squeue(np, i, cp->target, cp->lun, -1);

                /*
                 *  Make sure at least our IO to abort has been dequeued.
                 */
#ifndef SYM_OPT_HANDLE_DEVICE_QUEUEING
                assert(i && sym_get_cam_status(cp->cmd) == DID_SOFT_ERROR);
#else
                sym_remque(&cp->link_ccbq);
                sym_insque_tail(&cp->link_ccbq, &np->comp_ccbq);
#endif
                /*
                 *  Keep track in cam status of the reason of the abort.
                 */
                if (cp->to_abort == 2)
                        sym_set_cam_status(cp->cmd, DID_TIME_OUT);
                else
                        sym_set_cam_status(cp->cmd, DID_ABORT);

                /*
                 *  Complete with error everything that we have dequeued.
                 */
                sym_flush_comp_queue(np, 0);
                break;
        /*
         *  The SCRIPTS processor has selected a target 
         *  we may have some manual recovery to perform for.
         */
        case SIR_TARGET_SELECTED:
                target = INB(np, nc_sdid) & 0xf;
                tp = &np->target[target];

                np->abrt_tbl.addr = cpu_to_scr(vtobus(np->abrt_msg));

                /*
                 *  If the target is to be reset, prepare a 
                 *  M_RESET message and clear the to_reset flag 
                 *  since we donnot expect this operation to fail.
                 */
                if (tp->to_reset) {
                        np->abrt_msg[0] = M_RESET;
                        np->abrt_tbl.size = 1;
                        tp->to_reset = 0;
                        break;
                }

                /*
                 *  Otherwise, look for some logical unit to be cleared.
                 */
                if (tp->lun0p && tp->lun0p->to_clear)
                        lun = 0;
                else if (tp->lunmp) {
                        for (k = 1 ; k < SYM_CONF_MAX_LUN ; k++) {
                                if (tp->lunmp[k] && tp->lunmp[k]->to_clear) {
                                        lun = k;
                                        break;
                                }
                        }
                }

                /*
                 *  If a logical unit is to be cleared, prepare 
                 *  an IDENTIFY(lun) + ABORT MESSAGE.
                 */
                if (lun != -1) {
                        struct sym_lcb *lp = sym_lp(tp, lun);
                        lp->to_clear = 0; /* We don't expect to fail here */
                        np->abrt_msg[0] = IDENTIFY(0, lun);
                        np->abrt_msg[1] = M_ABORT;
                        np->abrt_tbl.size = 2;
                        break;
                }

                /*
                 *  Otherwise, look for some disconnected job to 
                 *  abort for this target.
                 */
                i = 0;
                cp = NULL;
                FOR_EACH_QUEUED_ELEMENT(&np->busy_ccbq, qp) {
                        cp = sym_que_entry(qp, struct sym_ccb, link_ccbq);
                        if (cp->host_status != HS_DISCONNECT)
                                continue;
                        if (cp->target != target)
                                continue;
                        if (!cp->to_abort)
                                continue;
                        i = 1;  /* Means we have some */
                        break;
                }

                /*
                 *  If we have none, probably since the device has 
                 *  completed the command before we won abitration,
                 *  send a M_ABORT message without IDENTIFY.
                 *  According to the specs, the device must just 
                 *  disconnect the BUS and not abort any task.
                 */
                if (!i) {
                        np->abrt_msg[0] = M_ABORT;
                        np->abrt_tbl.size = 1;
                        break;
                }

                /*
                 *  We have some task to abort.
                 *  Set the IDENTIFY(lun)
                 */
                np->abrt_msg[0] = IDENTIFY(0, cp->lun);

                /*
                 *  If we want to abort an untagged command, we 
                 *  will send a IDENTIFY + M_ABORT.
                 *  Otherwise (tagged command), we will send 
                 *  a IDENTITFY + task attributes + ABORT TAG.
                 */
                if (cp->tag == NO_TAG) {
                        np->abrt_msg[1] = M_ABORT;
                        np->abrt_tbl.size = 2;
                } else {
                        np->abrt_msg[1] = cp->scsi_smsg[1];
                        np->abrt_msg[2] = cp->scsi_smsg[2];
                        np->abrt_msg[3] = M_ABORT_TAG;
                        np->abrt_tbl.size = 4;
                }
                /*
                 *  Keep track of software timeout condition, since the 
                 *  peripheral driver may not count retries on abort 
                 *  conditions not due to timeout.
                 */
                if (cp->to_abort == 2)
                        sym_set_cam_status(cp->cmd, DID_TIME_OUT);
                cp->to_abort = 0; /* We donnot expect to fail here */
                break;

        /*
         *  The target has accepted our message and switched 
         *  to BUS FREE phase as we expected.
         */
        case SIR_ABORT_SENT:
                target = INB(np, nc_sdid) & 0xf;
                tp = &np->target[target];
                starget = tp->starget;
                
                /*
                **  If we didn't abort anything, leave here.
                */
                if (np->abrt_msg[0] == M_ABORT)
                        break;

                /*
                 *  If we sent a M_RESET, then a hardware reset has 
                 *  been performed by the target.
                 *  - Reset everything to async 8 bit
                 *  - Tell ourself to negotiate next time :-)
                 *  - Prepare to clear all disconnected CCBs for 
                 *    this target from our task list (lun=task=-1)
                 */
                lun = -1;
                task = -1;
                if (np->abrt_msg[0] == M_RESET) {
                        tp->head.sval = 0;
                        tp->head.wval = np->rv_scntl3;
                        tp->head.uval = 0;
                        spi_period(starget) = 0;
                        spi_offset(starget) = 0;
                        spi_width(starget) = 0;
                        spi_iu(starget) = 0;
                        spi_dt(starget) = 0;
                        spi_qas(starget) = 0;
                        tp->tgoal.check_nego = 1;
                }

                /*
                 *  Otherwise, check for the LUN and TASK(s) 
                 *  concerned by the cancelation.
                 *  If it is not ABORT_TAG then it is CLEAR_QUEUE 
                 *  or an ABORT message :-)
                 */
                else {
                        lun = np->abrt_msg[0] & 0x3f;
                        if (np->abrt_msg[1] == M_ABORT_TAG)
                                task = np->abrt_msg[2];
                }

                /*
                 *  Complete all the CCBs the device should have 
                 *  aborted due to our 'kiss of death' message.
                 */
                i = (INL(np, nc_scratcha) - np->squeue_ba) / 4;
                sym_dequeue_from_squeue(np, i, target, lun, -1);
                sym_clear_tasks(np, DID_ABORT, target, lun, task);
                sym_flush_comp_queue(np, 0);

                /*
                 *  If we sent a BDR, make upper layer aware of that.
                 */
                if (np->abrt_msg[0] == M_RESET)
                        sym_xpt_async_sent_bdr(np, target);
                break;
        }

        /*
         *  Print to the log the message we intend to send.
         */
        if (num == SIR_TARGET_SELECTED) {
                dev_info(&tp->starget->dev, "control msgout:");
                sym_printl_hex(np->abrt_msg, np->abrt_tbl.size);
                np->abrt_tbl.size = cpu_to_scr(np->abrt_tbl.size);
        }

        /*
         *  Let the SCRIPTS processor continue.
         */
        OUTONB_STD();
}

/*
 *  Gerard's alchemy:) that deals with with the data 
 *  pointer for both MDP and the residual calculation.
 *
 *  I didn't want to bloat the code by more than 200 
 *  lines for the handling of both MDP and the residual.
 *  This has been achieved by using a data pointer 
 *  representation consisting in an index in the data 
 *  array (dp_sg) and a negative offset (dp_ofs) that 
 *  have the following meaning:
 *
 *  - dp_sg = SYM_CONF_MAX_SG
 *    we are at the end of the data script.
 *  - dp_sg < SYM_CONF_MAX_SG
 *    dp_sg points to the next entry of the scatter array 
 *    we want to transfer.
 *  - dp_ofs < 0
 *    dp_ofs represents the residual of bytes of the 
 *    previous entry scatter entry we will send first.
 *  - dp_ofs = 0
 *    no residual to send first.
 *
 *  The function sym_evaluate_dp() accepts an arbitray 
 *  offset (basically from the MDP message) and returns 
 *  the corresponding values of dp_sg and dp_ofs.
 */

static int sym_evaluate_dp(struct sym_hcb *np, struct sym_ccb *cp, u32 scr, int *ofs)
{
        u32     dp_scr;
        int     dp_ofs, dp_sg, dp_sgmin;
        int     tmp;
        struct sym_pmc *pm;

        /*
         *  Compute the resulted data pointer in term of a script 
         *  address within some DATA script and a signed byte offset.
         */
        dp_scr = scr;
        dp_ofs = *ofs;
        if      (dp_scr == SCRIPTA_BA(np, pm0_data))
                pm = &cp->phys.pm0;
        else if (dp_scr == SCRIPTA_BA(np, pm1_data))
                pm = &cp->phys.pm1;
        else
                pm = NULL;

        if (pm) {
                dp_scr  = scr_to_cpu(pm->ret);
                dp_ofs -= scr_to_cpu(pm->sg.size);
        }

        /*
         *  If we are auto-sensing, then we are done.
         */
        if (cp->host_flags & HF_SENSE) {
                *ofs = dp_ofs;
                return 0;
        }

        /*
         *  Deduce the index of the sg entry.
         *  Keep track of the index of the first valid entry.
         *  If result is dp_sg = SYM_CONF_MAX_SG, then we are at the 
         *  end of the data.
         */
        tmp = scr_to_cpu(cp->goalp);
        dp_sg = SYM_CONF_MAX_SG;
        if (dp_scr != tmp)
                dp_sg -= (tmp - 8 - (int)dp_scr) / (2*4);
        dp_sgmin = SYM_CONF_MAX_SG - cp->segments;

        /*
         *  Move to the sg entry the data pointer belongs to.
         *
         *  If we are inside the data area, we expect result to be:
         *
         *  Either,
         *      dp_ofs = 0 and dp_sg is the index of the sg entry
         *      the data pointer belongs to (or the end of the data)
         *  Or,
         *      dp_ofs < 0 and dp_sg is the index of the sg entry 
         *      the data pointer belongs to + 1.
         */
        if (dp_ofs < 0) {
                int n;
                while (dp_sg > dp_sgmin) {
                        --dp_sg;
                        tmp = scr_to_cpu(cp->phys.data[dp_sg].size);
                        n = dp_ofs + (tmp & 0xffffff);
                        if (n > 0) {
                                ++dp_sg;
                                break;
                        }
                        dp_ofs = n;
                }
        }
        else if (dp_ofs > 0) {
                while (dp_sg < SYM_CONF_MAX_SG) {
                        tmp = scr_to_cpu(cp->phys.data[dp_sg].size);
                        dp_ofs -= (tmp & 0xffffff);
                        ++dp_sg;
                        if (dp_ofs <= 0)
                                break;
                }
        }

        /*
         *  Make sure the data pointer is inside the data area.
         *  If not, return some error.
         */
        if      (dp_sg < dp_sgmin || (dp_sg == dp_sgmin && dp_ofs < 0))
                goto out_err;
        else if (dp_sg > SYM_CONF_MAX_SG ||
                 (dp_sg == SYM_CONF_MAX_SG && dp_ofs > 0))
                goto out_err;

        /*
         *  Save the extreme pointer if needed.
         */
        if (dp_sg > cp->ext_sg ||
            (dp_sg == cp->ext_sg && dp_ofs > cp->ext_ofs)) {
                cp->ext_sg  = dp_sg;
                cp->ext_ofs = dp_ofs;
        }

        /*
         *  Return data.
         */
        *ofs = dp_ofs;
        return dp_sg;

out_err:
        return -1;
}

/*
 *  chip handler for MODIFY DATA POINTER MESSAGE
 *
 *  We also call this function on IGNORE WIDE RESIDUE 
 *  messages that do not match a SWIDE full condition.
 *  Btw, we assume in that situation that such a message 
 *  is equivalent to a MODIFY DATA POINTER (offset=-1).
 */

static void sym_modify_dp(struct sym_hcb *np, struct sym_tcb *tp, struct sym_ccb *cp, int ofs)
{
        int dp_ofs      = ofs;
        u32     dp_scr  = sym_get_script_dp (np, cp);
        u32     dp_ret;
        u32     tmp;
        u_char  hflags;
        int     dp_sg;
        struct  sym_pmc *pm;

        /*
         *  Not supported for auto-sense.
         */
        if (cp->host_flags & HF_SENSE)
                goto out_reject;

        /*
         *  Apply our alchemy:) (see comments in sym_evaluate_dp()), 
         *  to the resulted data pointer.
         */
        dp_sg = sym_evaluate_dp(np, cp, dp_scr, &dp_ofs);
        if (dp_sg < 0)
                goto out_reject;

        /*
         *  And our alchemy:) allows to easily calculate the data 
         *  script address we want to return for the next data phase.
         */
        dp_ret = cpu_to_scr(cp->goalp);
        dp_ret = dp_ret - 8 - (SYM_CONF_MAX_SG - dp_sg) * (2*4);

        /*
         *  If offset / scatter entry is zero we donnot need 
         *  a context for the new current data pointer.
         */
        if (dp_ofs == 0) {
                dp_scr = dp_ret;
                goto out_ok;
        }

        /*
         *  Get a context for the new current data pointer.
         */
        hflags = INB(np, HF_PRT);

        if (hflags & HF_DP_SAVED)
                hflags ^= HF_ACT_PM;

        if (!(hflags & HF_ACT_PM)) {
                pm  = &cp->phys.pm0;
                dp_scr = SCRIPTA_BA(np, pm0_data);
        }
        else {
                pm = &cp->phys.pm1;
                dp_scr = SCRIPTA_BA(np, pm1_data);
        }

        hflags &= ~(HF_DP_SAVED);

        OUTB(np, HF_PRT, hflags);

        /*
         *  Set up the new current data pointer.
         *  ofs < 0 there, and for the next data phase, we 
         *  want to transfer part of the data of the sg entry 
         *  corresponding to index dp_sg-1 prior to returning 
         *  to the main data script.
         */
        pm->ret = cpu_to_scr(dp_ret);
        tmp  = scr_to_cpu(cp->phys.data[dp_sg-1].addr);
        tmp += scr_to_cpu(cp->phys.data[dp_sg-1].size) + dp_ofs;
        pm->sg.addr = cpu_to_scr(tmp);
        pm->sg.size = cpu_to_scr(-dp_ofs);

out_ok:
        sym_set_script_dp (np, cp, dp_scr);
        OUTL_DSP(np, SCRIPTA_BA(np, clrack));
        return;

out_reject:
        OUTL_DSP(np, SCRIPTB_BA(np, msg_bad));
}


/*
 *  chip calculation of the data residual.
 *
 *  As I used to say, the requirement of data residual 
 *  in SCSI is broken, useless and cannot be achieved 
 *  without huge complexity.
 *  But most OSes and even the official CAM require it.
 *  When stupidity happens to be so widely spread inside 
 *  a community, it gets hard to convince.
 *
 *  Anyway, I don't care, since I am not going to use 
 *  any software that considers this data residual as 
 *  a relevant information. :)
 */

int sym_compute_residual(struct sym_hcb *np, struct sym_ccb *cp)
{
        int dp_sg, dp_sgmin, resid = 0;
        int dp_ofs = 0;

        /*
         *  Check for some data lost or just thrown away.
         *  We are not required to be quite accurate in this 
         *  situation. Btw, if we are odd for output and the 
         *  device claims some more data, it may well happen 
         *  than our residual be zero. :-)
         */
        if (cp->xerr_status & (XE_EXTRA_DATA|XE_SODL_UNRUN|XE_SWIDE_OVRUN)) {
                if (cp->xerr_status & XE_EXTRA_DATA)
                        resid -= cp->extra_bytes;
                if (cp->xerr_status & XE_SODL_UNRUN)
                        ++resid;
                if (cp->xerr_status & XE_SWIDE_OVRUN)
                        --resid;
        }

        /*
         *  If all data has been transferred,
         *  there is no residual.
         */
        if (cp->phys.head.lastp == cp->goalp)
                return resid;

        /*
         *  If no data transfer occurs, or if the data
         *  pointer is weird, return full residual.
         */
        if (cp->startp == cp->phys.head.lastp ||
            sym_evaluate_dp(np, cp, scr_to_cpu(cp->phys.head.lastp),
                            &dp_ofs) < 0) {
                return cp->data_len;
        }

        /*
         *  If we were auto-sensing, then we are done.
         */
        if (cp->host_flags & HF_SENSE) {
                return -dp_ofs;
        }

        /*
         *  We are now full comfortable in the computation 
         *  of the data residual (2's complement).
         */
        dp_sgmin = SYM_CONF_MAX_SG - cp->segments;
        resid = -cp->ext_ofs;
        for (dp_sg = cp->ext_sg; dp_sg < SYM_CONF_MAX_SG; ++dp_sg) {
                u_int tmp = scr_to_cpu(cp->phys.data[dp_sg].size);
                resid += (tmp & 0xffffff);
        }

        resid -= cp->odd_byte_adjustment;

        /*
         *  Hopefully, the result is not too wrong.
         */
        return resid;
}

/*
 *  Negotiation for WIDE and SYNCHRONOUS DATA TRANSFER.
 *
 *  When we try to negotiate, we append the negotiation message
 *  to the identify and (maybe) simple tag message.
 *  The host status field is set to HS_NEGOTIATE to mark this
 *  situation.
 *
 *  If the target doesn't answer this message immediately
 *  (as required by the standard), the SIR_NEGO_FAILED interrupt
 *  will be raised eventually.
 *  The handler removes the HS_NEGOTIATE status, and sets the
 *  negotiated value to the default (async / nowide).
 *
 *  If we receive a matching answer immediately, we check it
 *  for validity, and set the values.
 *
 *  If we receive a Reject message immediately, we assume the
 *  negotiation has failed, and fall back to standard values.
 *
 *  If we receive a negotiation message while not in HS_NEGOTIATE
 *  state, it's a target initiated negotiation. We prepare a
 *  (hopefully) valid answer, set our parameters, and send back 
 *  this answer to the target.
 *
 *  If the target doesn't fetch the answer (no message out phase),
 *  we assume the negotiation has failed, and fall back to default
 *  settings (SIR_NEGO_PROTO interrupt).
 *
 *  When we set the values, we adjust them in all ccbs belonging 
 *  to this target, in the controller's register, and in the "phys"
 *  field of the controller's struct sym_hcb.
 */

/*
 *  chip handler for SYNCHRONOUS DATA TRANSFER REQUEST (SDTR) message.
 */
static int  
sym_sync_nego_check(struct sym_hcb *np, int req, struct sym_ccb *cp)
{
        int target = cp->target;
        u_char  chg, ofs, per, fak, div;

        if (DEBUG_FLAGS & DEBUG_NEGO) {
                sym_print_nego_msg(np, target, "sync msgin", np->msgin);
        }

        /*
         *  Get requested values.
         */
        chg = 0;
        per = np->msgin[3];
        ofs = np->msgin[4];

        /*
         *  Check values against our limits.
         */
        if (ofs) {
                if (ofs > np->maxoffs)
                        {chg = 1; ofs = np->maxoffs;}
        }

        if (ofs) {
                if (per < np->minsync)
                        {chg = 1; per = np->minsync;}
        }

        /*
         *  Get new chip synchronous parameters value.
         */
        div = fak = 0;
        if (ofs && sym_getsync(np, 0, per, &div, &fak) < 0)
                goto reject_it;

        if (DEBUG_FLAGS & DEBUG_NEGO) {
                sym_print_addr(cp->cmd,
                                "sdtr: ofs=%d per=%d div=%d fak=%d chg=%d.\n",
                                ofs, per, div, fak, chg);
        }

        /*
         *  If it was an answer we want to change, 
         *  then it isn't acceptable. Reject it.
         */
        if (!req && chg)
                goto reject_it;

        /*
         *  Apply new values.
         */
        sym_setsync (np, target, ofs, per, div, fak);

        /*
         *  It was an answer. We are done.
         */
        if (!req)
                return 0;

        /*
         *  It was a request. Prepare an answer message.
         */
        np->msgout[0] = M_EXTENDED;
        np->msgout[1] = 3;
        np->msgout[2] = M_X_SYNC_REQ;
        np->msgout[3] = per;
        np->msgout[4] = ofs;

        if (DEBUG_FLAGS & DEBUG_NEGO) {
                sym_print_nego_msg(np, target, "sync msgout", np->msgout);
        }

        np->msgin [0] = M_NOOP;

        return 0;

reject_it:
        sym_setsync (np, target, 0, 0, 0, 0);
        return -1;
}

static void sym_sync_nego(struct sym_hcb *np, struct sym_tcb *tp, struct sym_ccb *cp)
{
        int req = 1;
        int result;

        /*
         *  Request or answer ?
         */
        if (INB(np, HS_PRT) == HS_NEGOTIATE) {
                OUTB(np, HS_PRT, HS_BUSY);
                if (cp->nego_status && cp->nego_status != NS_SYNC)
                        goto reject_it;
                req = 0;
        }

        /*
         *  Check and apply new values.
         */
        result = sym_sync_nego_check(np, req, cp);
        if (result)     /* Not acceptable, reject it */
                goto reject_it;
        if (req) {      /* Was a request, send response. */
                cp->nego_status = NS_SYNC;
                OUTL_DSP(np, SCRIPTB_BA(np, sdtr_resp));
        }
        else            /* Was a response, we are done. */
                OUTL_DSP(np, SCRIPTA_BA(np, clrack));
        return;

reject_it:
        OUTL_DSP(np, SCRIPTB_BA(np, msg_bad));
}

/*
 *  chip handler for PARALLEL PROTOCOL REQUEST (PPR) message.
 */
static int 
sym_ppr_nego_check(struct sym_hcb *np, int req, int target)
{
        struct sym_tcb *tp = &np->target[target];
        unsigned char fak, div;
        int dt, chg = 0;

        unsigned char per = np->msgin[3];
        unsigned char ofs = np->msgin[5];
        unsigned char wide = np->msgin[6];
        unsigned char opts = np->msgin[7] & PPR_OPT_MASK;

        if (DEBUG_FLAGS & DEBUG_NEGO) {
                sym_print_nego_msg(np, target, "ppr msgin", np->msgin);
        }

        /*
         *  Check values against our limits.
         */
        if (wide > np->maxwide) {
                chg = 1;
                wide = np->maxwide;
        }
        if (!wide || !(np->features & FE_U3EN))
                opts = 0;

        if (opts != (np->msgin[7] & PPR_OPT_MASK))
                chg = 1;

        dt = opts & PPR_OPT_DT;

        if (ofs) {
                unsigned char maxoffs = dt ? np->maxoffs_dt : np->maxoffs;
                if (ofs > maxoffs) {
                        chg = 1;
                        ofs = maxoffs;
                }
        }

        if (ofs) {
                unsigned char minsync = dt ? np->minsync_dt : np->minsync;
                if (per < minsync) {
                        chg = 1;
                        per = minsync;
                }
        }

        /*
         *  Get new chip synchronous parameters value.
         */
        div = fak = 0;
        if (ofs && sym_getsync(np, dt, per, &div, &fak) < 0)
                goto reject_it;

        /*
         *  If it was an answer we want to change, 
         *  then it isn't acceptable. Reject it.
         */
        if (!req && chg)
                goto reject_it;

        /*
         *  Apply new values.
         */
        sym_setpprot(np, target, opts, ofs, per, wide, div, fak);

        /*
         *  It was an answer. We are done.
         */
        if (!req)
                return 0;

        /*
         *  It was a request. Prepare an answer message.
         */
        np->msgout[0] = M_EXTENDED;
        np->msgout[1] = 6;
        np->msgout[2] = M_X_PPR_REQ;
        np->msgout[3] = per;
        np->msgout[4] = 0;
        np->msgout[5] = ofs;
        np->msgout[6] = wide;
        np->msgout[7] = opts;

        if (DEBUG_FLAGS & DEBUG_NEGO) {
                sym_print_nego_msg(np, target, "ppr msgout", np->msgout);
        }

        np->msgin [0] = M_NOOP;

        return 0;

reject_it:
        sym_setpprot (np, target, 0, 0, 0, 0, 0, 0);
        /*
         *  If it is a device response that should result in  
         *  ST, we may want to try a legacy negotiation later.
         */
        if (!req && !opts) {
                tp->tgoal.period = per;
                tp->tgoal.offset = ofs;
                tp->tgoal.width = wide;
                tp->tgoal.iu = tp->tgoal.dt = tp->tgoal.qas = 0;
                tp->tgoal.check_nego = 1;
        }
        return -1;
}

static void sym_ppr_nego(struct sym_hcb *np, struct sym_tcb *tp, struct sym_ccb *cp)
{
        int req = 1;
        int result;

        /*
         *  Request or answer ?
         */
        if (INB(np, HS_PRT) == HS_NEGOTIATE) {
                OUTB(np, HS_PRT, HS_BUSY);
                if (cp->nego_status && cp->nego_status != NS_PPR)
                        goto reject_it;
                req = 0;
        }

        /*
         *  Check and apply new values.
         */
        result = sym_ppr_nego_check(np, req, cp->target);
        if (result)     /* Not acceptable, reject it */
                goto reject_it;
        if (req) {      /* Was a request, send response. */
                cp->nego_status = NS_PPR;
                OUTL_DSP(np, SCRIPTB_BA(np, ppr_resp));
        }
        else            /* Was a response, we are done. */
                OUTL_DSP(np, SCRIPTA_BA(np, clrack));
        return;

reject_it:
        OUTL_DSP(np, SCRIPTB_BA(np, msg_bad));
}

/*
 *  chip handler for WIDE DATA TRANSFER REQUEST (WDTR) message.
 */
static int  
sym_wide_nego_check(struct sym_hcb *np, int req, struct sym_ccb *cp)
{
        int target = cp->target;
        u_char  chg, wide;

        if (DEBUG_FLAGS & DEBUG_NEGO) {
                sym_print_nego_msg(np, target, "wide msgin", np->msgin);
        }

        /*
         *  Get requested values.
         */
        chg  = 0;
        wide = np->msgin[3];

        /*
         *  Check values against our limits.
         */
        if (wide > np->maxwide) {
                chg = 1;
                wide = np->maxwide;
        }

        if (DEBUG_FLAGS & DEBUG_NEGO) {
                sym_print_addr(cp->cmd, "wdtr: wide=%d chg=%d.\n",
                                wide, chg);
        }

        /*
         *  If it was an answer we want to change, 
         *  then it isn't acceptable. Reject it.
         */
        if (!req && chg)
                goto reject_it;

        /*
         *  Apply new values.
         */
        sym_setwide (np, target, wide);

        /*
         *  It was an answer. We are done.
         */
        if (!req)
                return 0;

        /*
         *  It was a request. Prepare an answer message.
         */
        np->msgout[0] = M_EXTENDED;
        np->msgout[1] = 2;
        np->msgout[2] = M_X_WIDE_REQ;
        np->msgout[3] = wide;

        np->msgin [0] = M_NOOP;

        if (DEBUG_FLAGS & DEBUG_NEGO) {
                sym_print_nego_msg(np, target, "wide msgout", np->msgout);
        }

        return 0;

reject_it:
        return -1;
}

static void sym_wide_nego(struct sym_hcb *np, struct sym_tcb *tp, struct sym_ccb *cp)
{
        int req = 1;
        int result;

        /*
         *  Request or answer ?
         */
        if (INB(np, HS_PRT) == HS_NEGOTIATE) {
                OUTB(np, HS_PRT, HS_BUSY);
                if (cp->nego_status && cp->nego_status != NS_WIDE)
                        goto reject_it;
                req = 0;
        }

        /*
         *  Check and apply new values.
         */
        result = sym_wide_nego_check(np, req, cp);
        if (result)     /* Not acceptable, reject it */
                goto reject_it;
        if (req) {      /* Was a request, send response. */
                cp->nego_status = NS_WIDE;
                OUTL_DSP(np, SCRIPTB_BA(np, wdtr_resp));
        } else {                /* Was a response. */
                /*
                 * Negotiate for SYNC immediately after WIDE response.
                 * This allows to negotiate for both WIDE and SYNC on 
                 * a single SCSI command (Suggested by Justin Gibbs).
                 */
                if (tp->tgoal.offset) {
                        np->msgout[0] = M_EXTENDED;
                        np->msgout[1] = 3;
                        np->msgout[2] = M_X_SYNC_REQ;
                        np->msgout[3] = tp->tgoal.period;
                        np->msgout[4] = tp->tgoal.offset;

                        if (DEBUG_FLAGS & DEBUG_NEGO) {
                                sym_print_nego_msg(np, cp->target,
                                                   "sync msgout", np->msgout);
                        }

                        cp->nego_status = NS_SYNC;
                        OUTB(np, HS_PRT, HS_NEGOTIATE);
                        OUTL_DSP(np, SCRIPTB_BA(np, sdtr_resp));
                        return;
                } else
                        OUTL_DSP(np, SCRIPTA_BA(np, clrack));
        }

        return;

reject_it:
        OUTL_DSP(np, SCRIPTB_BA(np, msg_bad));
}

/*
 *  Reset DT, SYNC or WIDE to default settings.
 *
 *  Called when a negotiation does not succeed either 
 *  on rejection or on protocol error.
 *
 *  A target that understands a PPR message should never 
 *  reject it, and messing with it is very unlikely.
 *  So, if a PPR makes problems, we may just want to 
 *  try a legacy negotiation later.
 */
static void sym_nego_default(struct sym_hcb *np, struct sym_tcb *tp, struct sym_ccb *cp)
{
        switch (cp->nego_status) {
        case NS_PPR:
#if 0
                sym_setpprot (np, cp->target, 0, 0, 0, 0, 0, 0);
#else
                if (tp->tgoal.period < np->minsync)
                        tp->tgoal.period = np->minsync;
                if (tp->tgoal.offset > np->maxoffs)
                        tp->tgoal.offset = np->maxoffs;
                tp->tgoal.iu = tp->tgoal.dt = tp->tgoal.qas = 0;
                tp->tgoal.check_nego = 1;
#endif
                break;
        case NS_SYNC:
                sym_setsync (np, cp->target, 0, 0, 0, 0);
                break;
        case NS_WIDE:
                sym_setwide (np, cp->target, 0);
                break;
        }
        np->msgin [0] = M_NOOP;
        np->msgout[0] = M_NOOP;
        cp->nego_status = 0;
}

/*
 *  chip handler for MESSAGE REJECT received in response to 
 *  PPR, WIDE or SYNCHRONOUS negotiation.
 */
static void sym_nego_rejected(struct sym_hcb *np, struct sym_tcb *tp, struct sym_ccb *cp)
{
        sym_nego_default(np, tp, cp);
        OUTB(np, HS_PRT, HS_BUSY);
}

/*
 *  chip exception handler for programmed interrupts.
 */
static void sym_int_sir (struct sym_hcb *np)
{
        u_char  num     = INB(np, nc_dsps);
        u32     dsa     = INL(np, nc_dsa);
        struct sym_ccb *cp      = sym_ccb_from_dsa(np, dsa);
        u_char  target  = INB(np, nc_sdid) & 0x0f;
        struct sym_tcb *tp      = &np->target[target];
        int     tmp;

        if (DEBUG_FLAGS & DEBUG_TINY) printf ("I#%d", num);

        switch (num) {
#if   SYM_CONF_DMA_ADDRESSING_MODE == 2
        /*
         *  SCRIPTS tell us that we may have to update 
         *  64 bit DMA segment registers.
         */
        case SIR_DMAP_DIRTY:
                sym_update_dmap_regs(np);
                goto out;
#endif
        /*
         *  Command has been completed with error condition 
         *  or has been auto-sensed.
         */
        case SIR_COMPLETE_ERROR:
                sym_complete_error(np, cp);
                return;
        /*
         *  The C code is currently trying to recover from something.
         *  Typically, user want to abort some command.
         */
        case SIR_SCRIPT_STOPPED:
        case SIR_TARGET_SELECTED:
        case SIR_ABORT_SENT:
                sym_sir_task_recovery(np, num);
                return;
        /*
         *  The device didn't go to MSG OUT phase after having 
         *  been selected with ATN. We donnot want to handle 
         *  that.
         */
        case SIR_SEL_ATN_NO_MSG_OUT:
                printf ("%s:%d: No MSG OUT phase after selection with ATN.\n",
                        sym_name (np), target);
                goto out_stuck;
        /*
         *  The device didn't switch to MSG IN phase after 
         *  having reseleted the initiator.
         */
        case SIR_RESEL_NO_MSG_IN:
                printf ("%s:%d: No MSG IN phase after reselection.\n",
                        sym_name (np), target);
                goto out_stuck;
        /*
         *  After reselection, the device sent a message that wasn't 
         *  an IDENTIFY.
         */
        case SIR_RESEL_NO_IDENTIFY:
                printf ("%s:%d: No IDENTIFY after reselection.\n",
                        sym_name (np), target);
                goto out_stuck;
        /*
         *  The device reselected a LUN we donnot know about.
         */
        case SIR_RESEL_BAD_LUN:
                np->msgout[0] = M_RESET;
                goto out;
        /*
         *  The device reselected for an untagged nexus and we 
         *  haven't any.
         */
        case SIR_RESEL_BAD_I_T_L:
                np->msgout[0] = M_ABORT;
                goto out;
        /*
         *  The device reselected for a tagged nexus that we donnot 
         *  have.
         */
        case SIR_RESEL_BAD_I_T_L_Q:
                np->msgout[0] = M_ABORT_TAG;
                goto out;
        /*
         *  The SCRIPTS let us know that the device has grabbed 
         *  our message and will abort the job.
         */
        case SIR_RESEL_ABORTED:
                np->lastmsg = np->msgout[0];
                np->msgout[0] = M_NOOP;
                printf ("%s:%d: message %x sent on bad reselection.\n",
                        sym_name (np), target, np->lastmsg);
                goto out;
        /*
         *  The SCRIPTS let us know that a message has been 
         *  successfully sent to the device.
         */
        case SIR_MSG_OUT_DONE:
                np->lastmsg = np->msgout[0];
                np->msgout[0] = M_NOOP;
                /* Should we really care of that */
                if (np->lastmsg == M_PARITY || np->lastmsg == M_ID_ERROR) {
                        if (cp) {
                                cp->xerr_status &= ~XE_PARITY_ERR;
                                if (!cp->xerr_status)
                                        OUTOFFB(np, HF_PRT, HF_EXT_ERR);
                        }
                }
                goto out;
        /*
         *  The device didn't send a GOOD SCSI status.
         *  We may have some work to do prior to allow 
         *  the SCRIPTS processor to continue.
         */
        case SIR_BAD_SCSI_STATUS:
                if (!cp)
                        goto out;
                sym_sir_bad_scsi_status(np, num, cp);
                return;
        /*
         *  We are asked by the SCRIPTS to prepare a 
         *  REJECT message.
         */
        case SIR_REJECT_TO_SEND:
                sym_print_msg(cp, "M_REJECT to send for ", np->msgin);
                np->msgout[0] = M_REJECT;
                goto out;
        /*
         *  We have been ODD at the end of a DATA IN 
         *  transfer and the device didn't send a 
         *  IGNORE WIDE RESIDUE message.
         *  It is a data overrun condition.
         */
        case SIR_SWIDE_OVERRUN:
                if (cp) {
                        OUTONB(np, HF_PRT, HF_EXT_ERR);
                        cp->xerr_status |= XE_SWIDE_OVRUN;
                }
                goto out;
        /*
         *  We have been ODD at the end of a DATA OUT 
         *  transfer.
         *  It is a data underrun condition.
         */
        case SIR_SODL_UNDERRUN:
                if (cp) {
                        OUTONB(np, HF_PRT, HF_EXT_ERR);
                        cp->xerr_status |= XE_SODL_UNRUN;
                }
                goto out;
        /*
         *  The device wants us to tranfer more data than 
         *  expected or in the wrong direction.
         *  The number of extra bytes is in scratcha.
         *  It is a data overrun condition.
         */
        case SIR_DATA_OVERRUN:
                if (cp) {
                        OUTONB(np, HF_PRT, HF_EXT_ERR);
                        cp->xerr_status |= XE_EXTRA_DATA;
                        cp->extra_bytes += INL(np, nc_scratcha);
                }
                goto out;
        /*
         *  The device switched to an illegal phase (4/5).
         */
        case SIR_BAD_PHASE:
                if (cp) {
                        OUTONB(np, HF_PRT, HF_EXT_ERR);
                        cp->xerr_status |= XE_BAD_PHASE;
                }
                goto out;
        /*
         *  We received a message.
         */
        case SIR_MSG_RECEIVED:
                if (!cp)
                        goto out_stuck;
                switch (np->msgin [0]) {
                /*
                 *  We received an extended message.
                 *  We handle MODIFY DATA POINTER, SDTR, WDTR 
                 *  and reject all other extended messages.
                 */
                case M_EXTENDED:
                        switch (np->msgin [2]) {
                        case M_X_MODIFY_DP:
                                if (DEBUG_FLAGS & DEBUG_POINTER)
                                        sym_print_msg(cp,"modify DP",np->msgin);
                                tmp = (np->msgin[3]<<24) + (np->msgin[4]<<16) + 
                                      (np->msgin[5]<<8)  + (np->msgin[6]);
                                sym_modify_dp(np, tp, cp, tmp);
                                return;
                        case M_X_SYNC_REQ:
                                sym_sync_nego(np, tp, cp);
                                return;
                        case M_X_PPR_REQ:
                                sym_ppr_nego(np, tp, cp);
                                return;
                        case M_X_WIDE_REQ:
                                sym_wide_nego(np, tp, cp);
                                return;
                        default:
                                goto out_reject;
                        }
                        break;
                /*
                 *  We received a 1/2 byte message not handled from SCRIPTS.
                 *  We are only expecting MESSAGE REJECT and IGNORE WIDE 
                 *  RESIDUE messages that haven't been anticipated by 
                 *  SCRIPTS on SWIDE full condition. Unanticipated IGNORE 
                 *  WIDE RESIDUE messages are aliased as MODIFY DP (-1).
                 */
                case M_IGN_RESIDUE:
                        if (DEBUG_FLAGS & DEBUG_POINTER)
                                sym_print_msg(cp,"ign wide residue", np->msgin);
                        if (cp->host_flags & HF_SENSE)
                                OUTL_DSP(np, SCRIPTA_BA(np, clrack));
                        else
                                sym_modify_dp(np, tp, cp, -1);
                        return;
                case M_REJECT:
                        if (INB(np, HS_PRT) == HS_NEGOTIATE)
                                sym_nego_rejected(np, tp, cp);
                        else {
                                sym_print_addr(cp->cmd,
                                        "M_REJECT received (%x:%x).\n",
                                        scr_to_cpu(np->lastmsg), np->msgout[0]);
                        }
                        goto out_clrack;
                        break;
                default:
                        goto out_reject;
                }
                break;
        /*
         *  We received an unknown message.
         *  Ignore all MSG IN phases and reject it.
         */
        case SIR_MSG_WEIRD:
                sym_print_msg(cp, "WEIRD message received", np->msgin);
                OUTL_DSP(np, SCRIPTB_BA(np, msg_weird));
                return;
        /*
         *  Negotiation failed.
         *  Target does not send us the reply.
         *  Remove the HS_NEGOTIATE status.
         */
        case SIR_NEGO_FAILED:
                OUTB(np, HS_PRT, HS_BUSY);
        /*
         *  Negotiation failed.
         *  Target does not want answer message.
         */
        case SIR_NEGO_PROTO:
                sym_nego_default(np, tp, cp);
                goto out;
        }

out:
        OUTONB_STD();
        return;
out_reject:
        OUTL_DSP(np, SCRIPTB_BA(np, msg_bad));
        return;
out_clrack:
        OUTL_DSP(np, SCRIPTA_BA(np, clrack));
        return;
out_stuck:
        return;
}

/*
 *  Acquire a control block
 */
struct sym_ccb *sym_get_ccb (struct sym_hcb *np, struct scsi_cmnd *cmd, u_char tag_order)
{
        u_char tn = cmd->device->id;
        u_char ln = cmd->device->lun;
        struct sym_tcb *tp = &np->target[tn];
        struct sym_lcb *lp = sym_lp(tp, ln);
        u_short tag = NO_TAG;
        SYM_QUEHEAD *qp;
        struct sym_ccb *cp = NULL;

        /*
         *  Look for a free CCB
         */
        if (sym_que_empty(&np->free_ccbq))
                sym_alloc_ccb(np);
        qp = sym_remque_head(&np->free_ccbq);
        if (!qp)
                goto out;
        cp = sym_que_entry(qp, struct sym_ccb, link_ccbq);

        {
                /*
                 *  If we have been asked for a tagged command.
                 */
                if (tag_order) {
                        /*
                         *  Debugging purpose.
                         */
#ifndef SYM_OPT_HANDLE_DEVICE_QUEUEING
                        assert(lp->busy_itl == 0);
#endif
                        /*
                         *  Allocate resources for tags if not yet.
                         */
                        if (!lp->cb_tags) {
                                sym_alloc_lcb_tags(np, tn, ln);
                                if (!lp->cb_tags)
                                        goto out_free;
                        }
                        /*
                         *  Get a tag for this SCSI IO and set up
                         *  the CCB bus address for reselection, 
                         *  and count it for this LUN.
                         *  Toggle reselect path to tagged.
                         */
                        if (lp->busy_itlq < SYM_CONF_MAX_TASK) {
                                tag = lp->cb_tags[lp->ia_tag];
                                if (++lp->ia_tag == SYM_CONF_MAX_TASK)
                                        lp->ia_tag = 0;
                                ++lp->busy_itlq;
#ifndef SYM_OPT_HANDLE_DEVICE_QUEUEING
                                lp->itlq_tbl[tag] = cpu_to_scr(cp->ccb_ba);
                                lp->head.resel_sa =
                                        cpu_to_scr(SCRIPTA_BA(np, resel_tag));
#endif
#ifdef SYM_OPT_LIMIT_COMMAND_REORDERING
                                cp->tags_si = lp->tags_si;
                                ++lp->tags_sum[cp->tags_si];
                                ++lp->tags_since;
#endif
                        }
                        else
                                goto out_free;
                }
                /*
                 *  This command will not be tagged.
                 *  If we already have either a tagged or untagged 
                 *  one, refuse to overlap this untagged one.
                 */
                else {
                        /*
                         *  Debugging purpose.
                         */
#ifndef SYM_OPT_HANDLE_DEVICE_QUEUEING
                        assert(lp->busy_itl == 0 && lp->busy_itlq == 0);
#endif
                        /*
                         *  Count this nexus for this LUN.
                         *  Set up the CCB bus address for reselection.
                         *  Toggle reselect path to untagged.
                         */
                        ++lp->busy_itl;
#ifndef SYM_OPT_HANDLE_DEVICE_QUEUEING
                        if (lp->busy_itl == 1) {
                                lp->head.itl_task_sa = cpu_to_scr(cp->ccb_ba);
                                lp->head.resel_sa =
                                      cpu_to_scr(SCRIPTA_BA(np, resel_no_tag));
                        }
                        else
                                goto out_free;
#endif
                }
        }
        /*
         *  Put the CCB into the busy queue.
         */
        sym_insque_tail(&cp->link_ccbq, &np->busy_ccbq);
#ifdef SYM_OPT_HANDLE_DEVICE_QUEUEING
        if (lp) {
                sym_remque(&cp->link2_ccbq);
                sym_insque_tail(&cp->link2_ccbq, &lp->waiting_ccbq);
        }

#endif
        cp->to_abort = 0;
        cp->odd_byte_adjustment = 0;
        cp->tag    = tag;
        cp->order  = tag_order;
        cp->target = tn;
        cp->lun    = ln;

        if (DEBUG_FLAGS & DEBUG_TAGS) {
                sym_print_addr(cmd, "ccb @%p using tag %d.\n", cp, tag);
        }

out:
        return cp;
out_free:
        sym_insque_head(&cp->link_ccbq, &np->free_ccbq);
        return NULL;
}

/*
 *  Release one control block
 */
void sym_free_ccb (struct sym_hcb *np, struct sym_ccb *cp)
{
        struct sym_tcb *tp = &np->target[cp->target];
        struct sym_lcb *lp = sym_lp(tp, cp->lun);

        if (DEBUG_FLAGS & DEBUG_TAGS) {
                sym_print_addr(cp->cmd, "ccb @%p freeing tag %d.\n",
                                cp, cp->tag);
        }

        /*
         *  If LCB available,
         */
        if (lp) {
                /*
                 *  If tagged, release the tag, set the relect path 
                 */
                if (cp->tag != NO_TAG) {
#ifdef SYM_OPT_LIMIT_COMMAND_REORDERING
                        --lp->tags_sum[cp->tags_si];
#endif
                        /*
                         *  Free the tag value.
                         */
                        lp->cb_tags[lp->if_tag] = cp->tag;
                        if (++lp->if_tag == SYM_CONF_MAX_TASK)
                                lp->if_tag = 0;
                        /*
                         *  Make the reselect path invalid, 
                         *  and uncount this CCB.
                         */
                        lp->itlq_tbl[cp->tag] = cpu_to_scr(np->bad_itlq_ba);
                        --lp->busy_itlq;
                } else {        /* Untagged */
                        /*
                         *  Make the reselect path invalid, 
                         *  and uncount this CCB.
                         */
                        lp->head.itl_task_sa = cpu_to_scr(np->bad_itl_ba);
                        --lp->busy_itl;
                }
                /*
                 *  If no JOB active, make the LUN reselect path invalid.
                 */
                if (lp->busy_itlq == 0 && lp->busy_itl == 0)
                        lp->head.resel_sa =
                                cpu_to_scr(SCRIPTB_BA(np, resel_bad_lun));
        }

        /*
         *  We donnot queue more than 1 ccb per target 
         *  with negotiation at any time. If this ccb was 
         *  used for negotiation, clear this info in the tcb.
         */
        if (cp == tp->nego_cp)
                tp->nego_cp = NULL;

#ifdef SYM_CONF_IARB_SUPPORT
        /*
         *  If we just complete the last queued CCB,
         *  clear this info that is no longer relevant.
         */
        if (cp == np->last_cp)
                np->last_cp = 0;
#endif

        /*
         *  Make this CCB available.
         */
        cp->cmd = NULL;
        cp->host_status = HS_IDLE;
        sym_remque(&cp->link_ccbq);
        sym_insque_head(&cp->link_ccbq, &np->free_ccbq);

#ifdef SYM_OPT_HANDLE_DEVICE_QUEUEING
        if (lp) {
                sym_remque(&cp->link2_ccbq);
                sym_insque_tail(&cp->link2_ccbq, &np->dummy_ccbq);
                if (cp->started) {
                        if (cp->tag != NO_TAG)
                                --lp->started_tags;
                        else
                                --lp->started_no_tag;
                }
        }
        cp->started = 0;
#endif
}

/*
 *  Allocate a CCB from memory and initialize its fixed part.
 */
static struct sym_ccb *sym_alloc_ccb(struct sym_hcb *np)
{
        struct sym_ccb *cp = NULL;
        int hcode;

        /*
         *  Prevent from allocating more CCBs than we can 
         *  queue to the controller.
         */
        if (np->actccbs >= SYM_CONF_MAX_START)
                return NULL;

        /*
         *  Allocate memory for this CCB.
         */
        cp = sym_calloc_dma(sizeof(struct sym_ccb), "CCB");
        if (!cp)
                goto out_free;

        /*
         *  Count it.
         */
        np->actccbs++;

        /*
         *  Compute the bus address of this ccb.
         */
        cp->ccb_ba = vtobus(cp);

        /*
         *  Insert this ccb into the hashed list.
         */
        hcode = CCB_HASH_CODE(cp->ccb_ba);
        cp->link_ccbh = np->ccbh[hcode];
        np->ccbh[hcode] = cp;

        /*
         *  Initialyze the start and restart actions.
         */
        cp->phys.head.go.start   = cpu_to_scr(SCRIPTA_BA(np, idle));
        cp->phys.head.go.restart = cpu_to_scr(SCRIPTB_BA(np, bad_i_t_l));

        /*
         *  Initilialyze some other fields.
         */
        cp->phys.smsg_ext.addr = cpu_to_scr(HCB_BA(np, msgin[2]));

        /*
         *  Chain into free ccb queue.
         */
        sym_insque_head(&cp->link_ccbq, &np->free_ccbq);

        /*
         *  Chain into optionnal lists.
         */
#ifdef SYM_OPT_HANDLE_DEVICE_QUEUEING
        sym_insque_head(&cp->link2_ccbq, &np->dummy_ccbq);
#endif
        return cp;
out_free:
        if (cp)
                sym_mfree_dma(cp, sizeof(*cp), "CCB");
        return NULL;
}

/*
 *  Look up a CCB from a DSA value.
 */
static struct sym_ccb *sym_ccb_from_dsa(struct sym_hcb *np, u32 dsa)
{
        int hcode;
        struct sym_ccb *cp;

        hcode = CCB_HASH_CODE(dsa);
        cp = np->ccbh[hcode];
        while (cp) {
                if (cp->ccb_ba == dsa)
                        break;
                cp = cp->link_ccbh;
        }

        return cp;
}

/*
 *  Target control block initialisation.
 *  Nothing important to do at the moment.
 */
static void sym_init_tcb (struct sym_hcb *np, u_char tn)
{
#if 0   /*  Hmmm... this checking looks paranoid. */
        /*
         *  Check some alignments required by the chip.
         */     
        assert (((offsetof(struct sym_reg, nc_sxfer) ^
                offsetof(struct sym_tcb, head.sval)) &3) == 0);
        assert (((offsetof(struct sym_reg, nc_scntl3) ^
                offsetof(struct sym_tcb, head.wval)) &3) == 0);
#endif
}

/*
 *  Lun control block allocation and initialization.
 */
struct sym_lcb *sym_alloc_lcb (struct sym_hcb *np, u_char tn, u_char ln)
{
        struct sym_tcb *tp = &np->target[tn];
        struct sym_lcb *lp = NULL;

        /*
         *  Initialize the target control block if not yet.
         */
        sym_init_tcb (np, tn);

        /*
         *  Allocate the LCB bus address array.
         *  Compute the bus address of this table.
         */
        if (ln && !tp->luntbl) {
                int i;

                tp->luntbl = sym_calloc_dma(256, "LUNTBL");
                if (!tp->luntbl)
                        goto fail;
                for (i = 0 ; i < 64 ; i++)
                        tp->luntbl[i] = cpu_to_scr(vtobus(&np->badlun_sa));
                tp->head.luntbl_sa = cpu_to_scr(vtobus(tp->luntbl));
        }

        /*
         *  Allocate the table of pointers for LUN(s) > 0, if needed.
         */
        if (ln && !tp->lunmp) {
                tp->lunmp = kcalloc(SYM_CONF_MAX_LUN, sizeof(struct sym_lcb *),
                                GFP_KERNEL);
                if (!tp->lunmp)
                        goto fail;
        }

        /*
         *  Allocate the lcb.
         *  Make it available to the chip.
         */
        lp = sym_calloc_dma(sizeof(struct sym_lcb), "LCB");
        if (!lp)
                goto fail;
        if (ln) {
                tp->lunmp[ln] = lp;
                tp->luntbl[ln] = cpu_to_scr(vtobus(lp));
        }
        else {
                tp->lun0p = lp;
                tp->head.lun0_sa = cpu_to_scr(vtobus(lp));
        }

        /*
         *  Let the itl task point to error handling.
         */
        lp->head.itl_task_sa = cpu_to_scr(np->bad_itl_ba);

        /*
         *  Set the reselect pattern to our default. :)
         */
        lp->head.resel_sa = cpu_to_scr(SCRIPTB_BA(np, resel_bad_lun));

        /*
         *  Set user capabilities.
         */
        lp->user_flags = tp->usrflags & (SYM_DISC_ENABLED | SYM_TAGS_ENABLED);

#ifdef SYM_OPT_HANDLE_DEVICE_QUEUEING
        /*
         *  Initialize device queueing.
         */
        sym_que_init(&lp->waiting_ccbq);
        sym_que_init(&lp->started_ccbq);
        lp->started_max   = SYM_CONF_MAX_TASK;
        lp->started_limit = SYM_CONF_MAX_TASK;
#endif

fail:
        return lp;
}

/*
 *  Allocate LCB resources for tagged command queuing.
 */
static void sym_alloc_lcb_tags (struct sym_hcb *np, u_char tn, u_char ln)
{
        struct sym_tcb *tp = &np->target[tn];
        struct sym_lcb *lp = sym_lp(tp, ln);
        int i;

        /*
         *  Allocate the task table and and the tag allocation 
         *  circular buffer. We want both or none.
         */
        lp->itlq_tbl = sym_calloc_dma(SYM_CONF_MAX_TASK*4, "ITLQ_TBL");
        if (!lp->itlq_tbl)
                goto fail;
        lp->cb_tags = kcalloc(SYM_CONF_MAX_TASK, 1, GFP_ATOMIC);
        if (!lp->cb_tags) {
                sym_mfree_dma(lp->itlq_tbl, SYM_CONF_MAX_TASK*4, "ITLQ_TBL");
                lp->itlq_tbl = NULL;
                goto fail;
        }

        /*
         *  Initialize the task table with invalid entries.
         */
        for (i = 0 ; i < SYM_CONF_MAX_TASK ; i++)
                lp->itlq_tbl[i] = cpu_to_scr(np->notask_ba);

        /*
         *  Fill up the tag buffer with tag numbers.
         */
        for (i = 0 ; i < SYM_CONF_MAX_TASK ; i++)
                lp->cb_tags[i] = i;

        /*
         *  Make the task table available to SCRIPTS, 
         *  And accept tagged commands now.
         */
        lp->head.itlq_tbl_sa = cpu_to_scr(vtobus(lp->itlq_tbl));

        return;
fail:
        return;
}

/*
 *  Queue a SCSI IO to the controller.
 */
int sym_queue_scsiio(struct sym_hcb *np, struct scsi_cmnd *cmd, struct sym_ccb *cp)
{
        struct scsi_device *sdev = cmd->device;
        struct sym_tcb *tp;
        struct sym_lcb *lp;
        u_char  *msgptr;
        u_int   msglen;
        int can_disconnect;

        /*
         *  Keep track of the IO in our CCB.
         */
        cp->cmd = cmd;

        /*
         *  Retrieve the target descriptor.
         */
        tp = &np->target[cp->target];

        /*
         *  Retrieve the lun descriptor.
         */
        lp = sym_lp(tp, sdev->lun);

        can_disconnect = (cp->tag != NO_TAG) ||
                (lp && (lp->curr_flags & SYM_DISC_ENABLED));

        msgptr = cp->scsi_smsg;
        msglen = 0;
        msgptr[msglen++] = IDENTIFY(can_disconnect, sdev->lun);

        /*
         *  Build the tag message if present.
         */
        if (cp->tag != NO_TAG) {
                u_char order = cp->order;

                switch(order) {
                case M_ORDERED_TAG:
                        break;
                case M_HEAD_TAG:
                        break;
                default:
                        order = M_SIMPLE_TAG;
                }
#ifdef SYM_OPT_LIMIT_COMMAND_REORDERING
                /*
                 *  Avoid too much reordering of SCSI commands.
                 *  The algorithm tries to prevent completion of any 
                 *  tagged command from being delayed against more 
                 *  than 3 times the max number of queued commands.
                 */
                if (lp && lp->tags_since > 3*SYM_CONF_MAX_TAG) {
                        lp->tags_si = !(lp->tags_si);
                        if (lp->tags_sum[lp->tags_si]) {
                                order = M_ORDERED_TAG;
                                if ((DEBUG_FLAGS & DEBUG_TAGS)||sym_verbose>1) {
                                        sym_print_addr(cmd,
                                                "ordered tag forced.\n");
                                }
                        }
                        lp->tags_since = 0;
                }
#endif
                msgptr[msglen++] = order;

                /*
                 *  For less than 128 tags, actual tags are numbered 
                 *  1,3,5,..2*MAXTAGS+1,since we may have to deal 
                 *  with devices that have problems with #TAG 0 or too 
                 *  great #TAG numbers. For more tags (up to 256), 
                 *  we use directly our tag number.
                 */
#if SYM_CONF_MAX_TASK > (512/4)
                msgptr[msglen++] = cp->tag;
#else
                msgptr[msglen++] = (cp->tag << 1) + 1;
#endif
        }

        /*
         *  Build a negotiation message if needed.
         *  (nego_status is filled by sym_prepare_nego())
         */
        cp->nego_status = 0;
        if (tp->tgoal.check_nego && !tp->nego_cp && lp) {
                msglen += sym_prepare_nego(np, cp, msgptr + msglen);
        }

        /*
         *  Startqueue
         */
        cp->phys.head.go.start   = cpu_to_scr(SCRIPTA_BA(np, select));
        cp->phys.head.go.restart = cpu_to_scr(SCRIPTA_BA(np, resel_dsa));

        /*
         *  select
         */
        cp->phys.select.sel_id          = cp->target;
        cp->phys.select.sel_scntl3      = tp->head.wval;
        cp->phys.select.sel_sxfer       = tp->head.sval;
        cp->phys.select.sel_scntl4      = tp->head.uval;

        /*
         *  message
         */
        cp->phys.smsg.addr      = CCB_BA(cp, scsi_smsg);
        cp->phys.smsg.size      = cpu_to_scr(msglen);

        /*
         *  status
         */
        cp->host_xflags         = 0;
        cp->host_status         = cp->nego_status ? HS_NEGOTIATE : HS_BUSY;
        cp->ssss_status         = S_ILLEGAL;
        cp->xerr_status         = 0;
        cp->host_flags          = 0;
        cp->extra_bytes         = 0;

        /*
         *  extreme data pointer.
         *  shall be positive, so -1 is lower than lowest.:)
         */
        cp->ext_sg  = -1;
        cp->ext_ofs = 0;

        /*
         *  Build the CDB and DATA descriptor block 
         *  and start the IO.
         */
        return sym_setup_data_and_start(np, cmd, cp);
}

/*
 *  Reset a SCSI target (all LUNs of this target).
 */
int sym_reset_scsi_target(struct sym_hcb *np, int target)
{
        struct sym_tcb *tp;

        if (target == np->myaddr || (u_int)target >= SYM_CONF_MAX_TARGET)
                return -1;

        tp = &np->target[target];
        tp->to_reset = 1;

        np->istat_sem = SEM;
        OUTB(np, nc_istat, SIGP|SEM);

        return 0;
}

/*
 *  Abort a SCSI IO.
 */
static int sym_abort_ccb(struct sym_hcb *np, struct sym_ccb *cp, int timed_out)
{
        /*
         *  Check that the IO is active.
         */
        if (!cp || !cp->host_status || cp->host_status == HS_WAIT)
                return -1;

        /*
         *  If a previous abort didn't succeed in time,
         *  perform a BUS reset.
         */
        if (cp->to_abort) {
                sym_reset_scsi_bus(np, 1);
                return 0;
        }

        /*
         *  Mark the CCB for abort and allow time for.
         */
        cp->to_abort = timed_out ? 2 : 1;

        /*
         *  Tell the SCRIPTS processor to stop and synchronize with us.
         */
        np->istat_sem = SEM;
        OUTB(np, nc_istat, SIGP|SEM);
        return 0;
}

int sym_abort_scsiio(struct sym_hcb *np, struct scsi_cmnd *cmd, int timed_out)
{
        struct sym_ccb *cp;
        SYM_QUEHEAD *qp;

        /*
         *  Look up our CCB control block.
         */
        cp = NULL;
        FOR_EACH_QUEUED_ELEMENT(&np->busy_ccbq, qp) {
                struct sym_ccb *cp2 = sym_que_entry(qp, struct sym_ccb, link_ccbq);
                if (cp2->cmd == cmd) {
                        cp = cp2;
                        break;
                }
        }

        return sym_abort_ccb(np, cp, timed_out);
}

/*
 *  Complete execution of a SCSI command with extended 
 *  error, SCSI status error, or having been auto-sensed.
 *
 *  The SCRIPTS processor is not running there, so we 
 *  can safely access IO registers and remove JOBs from  
 *  the START queue.
 *  SCRATCHA is assumed to have been loaded with STARTPOS 
 *  before the SCRIPTS called the C code.
 */
void sym_complete_error(struct sym_hcb *np, struct sym_ccb *cp)
{
        struct scsi_device *sdev;
        struct scsi_cmnd *cmd;
        struct sym_tcb *tp;
        struct sym_lcb *lp;
        int resid;
        int i;

        /*
         *  Paranoid check. :)
         */
        if (!cp || !cp->cmd)
                return;

        cmd = cp->cmd;
        sdev = cmd->device;
        if (DEBUG_FLAGS & (DEBUG_TINY|DEBUG_RESULT)) {
                dev_info(&sdev->sdev_gendev, "CCB=%p STAT=%x/%x/%x\n", cp,
                        cp->host_status, cp->ssss_status, cp->host_flags);
        }

        /*
         *  Get target and lun pointers.
         */
        tp = &np->target[cp->target];
        lp = sym_lp(tp, sdev->lun);

        /*
         *  Check for extended errors.
         */
        if (cp->xerr_status) {
                if (sym_verbose)
                        sym_print_xerr(cmd, cp->xerr_status);
                if (cp->host_status == HS_COMPLETE)
                        cp->host_status = HS_COMP_ERR;
        }

        /*
         *  Calculate the residual.
         */
        resid = sym_compute_residual(np, cp);

        if (!SYM_SETUP_RESIDUAL_SUPPORT) {/* If user does not want residuals */
                resid  = 0;              /* throw them away. :)             */
                cp->sv_resid = 0;
        }
#ifdef DEBUG_2_0_X
if (resid)
        printf("XXXX RESID= %d - 0x%x\n", resid, resid);
#endif

        /*
         *  Dequeue all queued CCBs for that device 
         *  not yet started by SCRIPTS.
         */
        i = (INL(np, nc_scratcha) - np->squeue_ba) / 4;
        i = sym_dequeue_from_squeue(np, i, cp->target, sdev->lun, -1);

        /*
         *  Restart the SCRIPTS processor.
         */
        OUTL_DSP(np, SCRIPTA_BA(np, start));

#ifdef SYM_OPT_HANDLE_DEVICE_QUEUEING
        if (cp->host_status == HS_COMPLETE &&
            cp->ssss_status == S_QUEUE_FULL) {
                if (!lp || lp->started_tags - i < 2)
                        goto weirdness;
                /*
                 *  Decrease queue depth as needed.
                 */
                lp->started_max = lp->started_tags - i - 1;
                lp->num_sgood = 0;

                if (sym_verbose >= 2) {
                        sym_print_addr(cmd, " queue depth is now %d\n",
                                        lp->started_max);
                }

                /*
                 *  Repair the CCB.
                 */
                cp->host_status = HS_BUSY;
                cp->ssss_status = S_ILLEGAL;

                /*
                 *  Let's requeue it to device.
                 */
                sym_set_cam_status(cmd, DID_SOFT_ERROR);
                goto finish;
        }
weirdness:
#endif
        /*
         *  Build result in CAM ccb.
         */
        sym_set_cam_result_error(np, cp, resid);

#ifdef SYM_OPT_HANDLE_DEVICE_QUEUEING
finish:
#endif
        /*
         *  Add this one to the COMP queue.
         */
        sym_remque(&cp->link_ccbq);
        sym_insque_head(&cp->link_ccbq, &np->comp_ccbq);

        /*
         *  Complete all those commands with either error 
         *  or requeue condition.
         */
        sym_flush_comp_queue(np, 0);

#ifdef SYM_OPT_HANDLE_DEVICE_QUEUEING
        /*
         *  Donnot start more than 1 command after an error.
         */
        sym_start_next_ccbs(np, lp, 1);
#endif
}

/*
 *  Complete execution of a successful SCSI command.
 *
 *  Only successful commands go to the DONE queue, 
 *  since we need to have the SCRIPTS processor 
 *  stopped on any error condition.
 *  The SCRIPTS processor is running while we are 
 *  completing successful commands.
 */
void sym_complete_ok (struct sym_hcb *np, struct sym_ccb *cp)
{
        struct sym_tcb *tp;
        struct sym_lcb *lp;
        struct scsi_cmnd *cmd;
        int resid;

        /*
         *  Paranoid check. :)
         */
        if (!cp || !cp->cmd)
                return;
        assert (cp->host_status == HS_COMPLETE);

        /*
         *  Get user command.
         */
        cmd = cp->cmd;

        /*
         *  Get target and lun pointers.
         */
        tp = &np->target[cp->target];
        lp = sym_lp(tp, cp->lun);

        /*
         *  If all data have been transferred, given than no
         *  extended error did occur, there is no residual.
         */
        resid = 0;
        if (cp->phys.head.lastp != cp->goalp)
                resid = sym_compute_residual(np, cp);

        /*
         *  Wrong transfer residuals may be worse than just always 
         *  returning zero. User can disable this feature in 
         *  sym53c8xx.h. Residual support is enabled by default.
         */
        if (!SYM_SETUP_RESIDUAL_SUPPORT)
                resid  = 0;
#ifdef DEBUG_2_0_X
if (resid)
        printf("XXXX RESID= %d - 0x%x\n", resid, resid);
#endif

        /*
         *  Build result in CAM ccb.
         */
        sym_set_cam_result_ok(cp, cmd, resid);

#ifdef SYM_OPT_HANDLE_DEVICE_QUEUEING
        /*
         *  If max number of started ccbs had been reduced,
         *  increase it if 200 good status received.
         */
        if (lp && lp->started_max < lp->started_limit) {
                ++lp->num_sgood;
                if (lp->num_sgood >= 200) {
                        lp->num_sgood = 0;
                        ++lp->started_max;
                        if (sym_verbose >= 2) {
                                sym_print_addr(cmd, " queue depth is now %d\n",
                                       lp->started_max);
                        }
                }
        }
#endif

        /*
         *  Free our CCB.
         */
        sym_free_ccb (np, cp);

#ifdef SYM_OPT_HANDLE_DEVICE_QUEUEING
        /*
         *  Requeue a couple of awaiting scsi commands.
         */
        if (!sym_que_empty(&lp->waiting_ccbq))
                sym_start_next_ccbs(np, lp, 2);
#endif
        /*
         *  Complete the command.
         */
        sym_xpt_done(np, cmd);
}

/*
 *  Soft-attach the controller.
 */
int sym_hcb_attach(struct Scsi_Host *shost, struct sym_fw *fw, struct sym_nvram *nvram)
{
        struct sym_hcb *np = sym_get_hcb(shost);
        int i;

        /*
         *  Get some info about the firmware.
         */
        np->scripta_sz   = fw->a_size;
        np->scriptb_sz   = fw->b_size;
        np->scriptz_sz   = fw->z_size;
        np->fw_setup     = fw->setup;
        np->fw_patch     = fw->patch;
        np->fw_name      = fw->name;

        /*
         *  Save setting of some IO registers, so we will 
         *  be able to probe specific implementations.
         */
        sym_save_initial_setting (np);

        /*
         *  Reset the chip now, since it has been reported 
         *  that SCSI clock calibration may not work properly 
         *  if the chip is currently active.
         */
        sym_chip_reset(np);

        /*
         *  Prepare controller and devices settings, according 
         *  to chip features, user set-up and driver set-up.
         */
        sym_prepare_setting(shost, np, nvram);

        /*
         *  Check the PCI clock frequency.
         *  Must be performed after prepare_setting since it destroys 
         *  STEST1 that is used to probe for the clock doubler.
         */
        i = sym_getpciclock(np);
        if (i > 37000 && !(np->features & FE_66MHZ))
                printf("%s: PCI BUS clock seems too high: %u KHz.\n",
                        sym_name(np), i);

        /*
         *  Allocate the start queue.
         */
        np->squeue = sym_calloc_dma(sizeof(u32)*(MAX_QUEUE*2),"SQUEUE");
        if (!np->squeue)
                goto attach_failed;
        np->squeue_ba = vtobus(np->squeue);

        /*
         *  Allocate the done queue.
         */
        np->dqueue = sym_calloc_dma(sizeof(u32)*(MAX_QUEUE*2),"DQUEUE");
        if (!np->dqueue)
                goto attach_failed;
        np->dqueue_ba = vtobus(np->dqueue);

        /*
         *  Allocate the target bus address array.
         */
        np->targtbl = sym_calloc_dma(256, "TARGTBL");
        if (!np->targtbl)
                goto attach_failed;
        np->targtbl_ba = vtobus(np->targtbl);

        /*
         *  Allocate SCRIPTS areas.
         */
        np->scripta0 = sym_calloc_dma(np->scripta_sz, "SCRIPTA0");
        np->scriptb0 = sym_calloc_dma(np->scriptb_sz, "SCRIPTB0");
        np->scriptz0 = sym_calloc_dma(np->scriptz_sz, "SCRIPTZ0");
        if (!np->scripta0 || !np->scriptb0 || !np->scriptz0)
                goto attach_failed;

        /*
         *  Allocate the array of lists of CCBs hashed by DSA.
         */
        np->ccbh = kcalloc(sizeof(struct sym_ccb **), CCB_HASH_SIZE, GFP_KERNEL);
        if (!np->ccbh)
                goto attach_failed;

        /*
         *  Initialyze the CCB free and busy queues.
         */
        sym_que_init(&np->free_ccbq);
        sym_que_init(&np->busy_ccbq);
        sym_que_init(&np->comp_ccbq);

        /*
         *  Initialization for optional handling 
         *  of device queueing.
         */
#ifdef SYM_OPT_HANDLE_DEVICE_QUEUEING
        sym_que_init(&np->dummy_ccbq);
#endif
        /*
         *  Allocate some CCB. We need at least ONE.
         */
        if (!sym_alloc_ccb(np))
                goto attach_failed;

        /*
         *  Calculate BUS addresses where we are going 
         *  to load the SCRIPTS.
         */
        np->scripta_ba  = vtobus(np->scripta0);
        np->scriptb_ba  = vtobus(np->scriptb0);
        np->scriptz_ba  = vtobus(np->scriptz0);

        if (np->ram_ba) {
                np->scripta_ba  = np->ram_ba;
                if (np->features & FE_RAM8K) {
                        np->ram_ws = 8192;
                        np->scriptb_ba = np->scripta_ba + 4096;
#if 0   /* May get useful for 64 BIT PCI addressing */
                        np->scr_ram_seg = cpu_to_scr(np->scripta_ba >> 32);
#endif
                }
                else
                        np->ram_ws = 4096;
        }

        /*
         *  Copy scripts to controller instance.
         */
        memcpy(np->scripta0, fw->a_base, np->scripta_sz);
        memcpy(np->scriptb0, fw->b_base, np->scriptb_sz);
        memcpy(np->scriptz0, fw->z_base, np->scriptz_sz);

        /*
         *  Setup variable parts in scripts and compute
         *  scripts bus addresses used from the C code.
         */
        np->fw_setup(np, fw);

        /*
         *  Bind SCRIPTS with physical addresses usable by the 
         *  SCRIPTS processor (as seen from the BUS = BUS addresses).
         */
        sym_fw_bind_script(np, (u32 *) np->scripta0, np->scripta_sz);
        sym_fw_bind_script(np, (u32 *) np->scriptb0, np->scriptb_sz);
        sym_fw_bind_script(np, (u32 *) np->scriptz0, np->scriptz_sz);

#ifdef SYM_CONF_IARB_SUPPORT
        /*
         *    If user wants IARB to be set when we win arbitration 
         *    and have other jobs, compute the max number of consecutive 
         *    settings of IARB hints before we leave devices a chance to 
         *    arbitrate for reselection.
         */
#ifdef  SYM_SETUP_IARB_MAX
        np->iarb_max = SYM_SETUP_IARB_MAX;
#else
        np->iarb_max = 4;
#endif
#endif

        /*
         *  Prepare the idle and invalid task actions.
         */
        np->idletask.start      = cpu_to_scr(SCRIPTA_BA(np, idle));
        np->idletask.restart    = cpu_to_scr(SCRIPTB_BA(np, bad_i_t_l));
        np->idletask_ba         = vtobus(&np->idletask);

        np->notask.start        = cpu_to_scr(SCRIPTA_BA(np, idle));
        np->notask.restart      = cpu_to_scr(SCRIPTB_BA(np, bad_i_t_l));
        np->notask_ba           = vtobus(&np->notask);

        np->bad_itl.start       = cpu_to_scr(SCRIPTA_BA(np, idle));
        np->bad_itl.restart     = cpu_to_scr(SCRIPTB_BA(np, bad_i_t_l));
        np->bad_itl_ba          = vtobus(&np->bad_itl);

        np->bad_itlq.start      = cpu_to_scr(SCRIPTA_BA(np, idle));
        np->bad_itlq.restart    = cpu_to_scr(SCRIPTB_BA(np,bad_i_t_l_q));
        np->bad_itlq_ba         = vtobus(&np->bad_itlq);

        /*
         *  Allocate and prepare the lun JUMP table that is used 
         *  for a target prior the probing of devices (bad lun table).
         *  A private table will be allocated for the target on the 
         *  first INQUIRY response received.
         */
        np->badluntbl = sym_calloc_dma(256, "BADLUNTBL");
        if (!np->badluntbl)
                goto attach_failed;

        np->badlun_sa = cpu_to_scr(SCRIPTB_BA(np, resel_bad_lun));
        for (i = 0 ; i < 64 ; i++)      /* 64 luns/target, no less */
                np->badluntbl[i] = cpu_to_scr(vtobus(&np->badlun_sa));

        /*
         *  Prepare the bus address array that contains the bus 
         *  address of each target control block.
         *  For now, assume all logical units are wrong. :)
         */
        for (i = 0 ; i < SYM_CONF_MAX_TARGET ; i++) {
                np->targtbl[i] = cpu_to_scr(vtobus(&np->target[i]));
                np->target[i].head.luntbl_sa =
                                cpu_to_scr(vtobus(np->badluntbl));
                np->target[i].head.lun0_sa =
                                cpu_to_scr(vtobus(&np->badlun_sa));
        }

        /*
         *  Now check the cache handling of the pci chipset.
         */
        if (sym_snooptest (np)) {
                printf("%s: CACHE INCORRECTLY CONFIGURED.\n", sym_name(np));
                goto attach_failed;
        }

        /*
         *  Sigh! we are done.
         */
        return 0;

attach_failed:
        return -ENXIO;
}

/*
 *  Free everything that has been allocated for this device.
 */
void sym_hcb_free(struct sym_hcb *np)
{
        SYM_QUEHEAD *qp;
        struct sym_ccb *cp;
        struct sym_tcb *tp;
        int target;

        if (np->scriptz0)
                sym_mfree_dma(np->scriptz0, np->scriptz_sz, "SCRIPTZ0");
        if (np->scriptb0)
                sym_mfree_dma(np->scriptb0, np->scriptb_sz, "SCRIPTB0");
        if (np->scripta0)
                sym_mfree_dma(np->scripta0, np->scripta_sz, "SCRIPTA0");
        if (np->squeue)
                sym_mfree_dma(np->squeue, sizeof(u32)*(MAX_QUEUE*2), "SQUEUE");
        if (np->dqueue)
                sym_mfree_dma(np->dqueue, sizeof(u32)*(MAX_QUEUE*2), "DQUEUE");

        if (np->actccbs) {
                while ((qp = sym_remque_head(&np->free_ccbq)) != 0) {
                        cp = sym_que_entry(qp, struct sym_ccb, link_ccbq);
                        sym_mfree_dma(cp, sizeof(*cp), "CCB");
                }
        }
        kfree(np->ccbh);

        if (np->badluntbl)
                sym_mfree_dma(np->badluntbl, 256,"BADLUNTBL");

        for (target = 0; target < SYM_CONF_MAX_TARGET ; target++) {
                tp = &np->target[target];
#if SYM_CONF_MAX_LUN > 1
                kfree(tp->lunmp);
#endif 
        }
        if (np->targtbl)
                sym_mfree_dma(np->targtbl, 256, "TARGTBL");
}