writeback: Add tracing to balance_dirty_pages

[linux-2.6/next.git] / drivers / scsi / in2000.c

/*
 *    in2000.c -  Linux device driver for the
 *                Always IN2000 ISA SCSI card.
 *
 * Copyright (c) 1996 John Shifflett, GeoLog Consulting
 *    john@geolog.com
 *    jshiffle@netcom.com
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * For the avoidance of doubt the "preferred form" of this code is one which
 * is in an open non patent encumbered format. Where cryptographic key signing
 * forms part of the process of creating an executable the information
 * including keys needed to generate an equivalently functional executable
 * are deemed to be part of the source code.
 *
 * Drew Eckhardt's excellent 'Generic NCR5380' sources provided
 * much of the inspiration and some of the code for this driver.
 * The Linux IN2000 driver distributed in the Linux kernels through
 * version 1.2.13 was an extremely valuable reference on the arcane
 * (and still mysterious) workings of the IN2000's fifo. It also
 * is where I lifted in2000_biosparam(), the gist of the card
 * detection scheme, and other bits of code. Many thanks to the
 * talented and courageous people who wrote, contributed to, and
 * maintained that driver (including Brad McLean, Shaun Savage,
 * Bill Earnest, Larry Doolittle, Roger Sunshine, John Luckey,
 * Matt Postiff, Peter Lu, zerucha@shell.portal.com, and Eric
 * Youngdale). I should also mention the driver written by
 * Hamish Macdonald for the (GASP!) Amiga A2091 card, included
 * in the Linux-m68k distribution; it gave me a good initial
 * understanding of the proper way to run a WD33c93 chip, and I
 * ended up stealing lots of code from it.
 *
 * _This_ driver is (I feel) an improvement over the old one in
 * several respects:
 *    -  All problems relating to the data size of a SCSI request are
 *          gone (as far as I know). The old driver couldn't handle
 *          swapping to partitions because that involved 4k blocks, nor
 *          could it deal with the st.c tape driver unmodified, because
 *          that usually involved 4k - 32k blocks. The old driver never
 *          quite got away from a morbid dependence on 2k block sizes -
 *          which of course is the size of the card's fifo.
 *
 *    -  Target Disconnection/Reconnection is now supported. Any
 *          system with more than one device active on the SCSI bus
 *          will benefit from this. The driver defaults to what I'm
 *          calling 'adaptive disconnect' - meaning that each command
 *          is evaluated individually as to whether or not it should
 *          be run with the option to disconnect/reselect (if the
 *          device chooses), or as a "SCSI-bus-hog".
 *
 *    -  Synchronous data transfers are now supported. Because there
 *          are a few devices (and many improperly terminated systems)
 *          that choke when doing sync, the default is sync DISABLED
 *          for all devices. This faster protocol can (and should!)
 *          be enabled on selected devices via the command-line.
 *
 *    -  Runtime operating parameters can now be specified through
 *       either the LILO or the 'insmod' command line. For LILO do:
 *          "in2000=blah,blah,blah"
 *       and with insmod go like:
 *          "insmod /usr/src/linux/modules/in2000.o setup_strings=blah,blah"
 *       The defaults should be good for most people. See the comment
 *       for 'setup_strings' below for more details.
 *
 *    -  The old driver relied exclusively on what the Western Digital
 *          docs call "Combination Level 2 Commands", which are a great
 *          idea in that the CPU is relieved of a lot of interrupt
 *          overhead. However, by accepting a certain (user-settable)
 *          amount of additional interrupts, this driver achieves
 *          better control over the SCSI bus, and data transfers are
 *          almost as fast while being much easier to define, track,
 *          and debug.
 *
 *    -  You can force detection of a card whose BIOS has been disabled.
 *
 *    -  Multiple IN2000 cards might almost be supported. I've tried to
 *       keep it in mind, but have no way to test...
 *
 *
 * TODO:
 *       tagged queuing. multiple cards.
 *
 *
 * NOTE:
 *       When using this or any other SCSI driver as a module, you'll
 *       find that with the stock kernel, at most _two_ SCSI hard
 *       drives will be linked into the device list (ie, usable).
 *       If your IN2000 card has more than 2 disks on its bus, you
 *       might want to change the define of 'SD_EXTRA_DEVS' in the
 *       'hosts.h' file from 2 to whatever is appropriate. It took
 *       me a while to track down this surprisingly obscure and
 *       undocumented little "feature".
 *
 *
 * People with bug reports, wish-lists, complaints, comments,
 * or improvements are asked to pah-leeez email me (John Shifflett)
 * at john@geolog.com or jshiffle@netcom.com! I'm anxious to get
 * this thing into as good a shape as possible, and I'm positive
 * there are lots of lurking bugs and "Stupid Places".
 *
 * Updated for Linux 2.5 by Alan Cox <alan@lxorguk.ukuu.org.uk>
 *      - Using new_eh handler
 *      - Hopefully got all the locking right again
 *      See "FIXME" notes for items that could do with more work
 */

#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/interrupt.h>
#include <linux/string.h>
#include <linux/delay.h>
#include <linux/proc_fs.h>
#include <linux/ioport.h>
#include <linux/stat.h>

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

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

#define IN2000_VERSION    "1.33-2.5"
#define IN2000_DATE       "2002/11/03"

#include "in2000.h"


/*
 * 'setup_strings' is a single string used to pass operating parameters and
 * settings from the kernel/module command-line to the driver. 'setup_args[]'
 * is an array of strings that define the compile-time default values for
 * these settings. If Linux boots with a LILO or insmod command-line, those
 * settings are combined with 'setup_args[]'. Note that LILO command-lines
 * are prefixed with "in2000=" while insmod uses a "setup_strings=" prefix.
 * The driver recognizes the following keywords (lower case required) and
 * arguments:
 *
 * -  ioport:addr    -Where addr is IO address of a (usually ROM-less) card.
 * -  noreset        -No optional args. Prevents SCSI bus reset at boot time.
 * -  nosync:x       -x is a bitmask where the 1st 7 bits correspond with
 *                    the 7 possible SCSI devices (bit 0 for device #0, etc).
 *                    Set a bit to PREVENT sync negotiation on that device.
 *                    The driver default is sync DISABLED on all devices.
 * -  period:ns      -ns is the minimum # of nanoseconds in a SCSI data transfer
 *                    period. Default is 500; acceptable values are 250 - 1000.
 * -  disconnect:x   -x = 0 to never allow disconnects, 2 to always allow them.
 *                    x = 1 does 'adaptive' disconnects, which is the default
 *                    and generally the best choice.
 * -  debug:x        -If 'DEBUGGING_ON' is defined, x is a bitmask that causes
 *                    various types of debug output to printed - see the DB_xxx
 *                    defines in in2000.h
 * -  proc:x         -If 'PROC_INTERFACE' is defined, x is a bitmask that
 *                    determines how the /proc interface works and what it
 *                    does - see the PR_xxx defines in in2000.h
 *
 * Syntax Notes:
 * -  Numeric arguments can be decimal or the '0x' form of hex notation. There
 *    _must_ be a colon between a keyword and its numeric argument, with no
 *    spaces.
 * -  Keywords are separated by commas, no spaces, in the standard kernel
 *    command-line manner.
 * -  A keyword in the 'nth' comma-separated command-line member will overwrite
 *    the 'nth' element of setup_args[]. A blank command-line member (in
 *    other words, a comma with no preceding keyword) will _not_ overwrite
 *    the corresponding setup_args[] element.
 *
 * A few LILO examples (for insmod, use 'setup_strings' instead of 'in2000'):
 * -  in2000=ioport:0x220,noreset
 * -  in2000=period:250,disconnect:2,nosync:0x03
 * -  in2000=debug:0x1e
 * -  in2000=proc:3
 */

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

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

module_param(setup_strings, charp, 0);

static inline uchar read_3393(struct IN2000_hostdata *hostdata, uchar reg_num)
{
        write1_io(reg_num, IO_WD_ADDR);
        return read1_io(IO_WD_DATA);
}


#define READ_AUX_STAT() read1_io(IO_WD_ASR)


static inline void write_3393(struct IN2000_hostdata *hostdata, uchar reg_num, uchar value)
{
        write1_io(reg_num, IO_WD_ADDR);
        write1_io(value, IO_WD_DATA);
}


static inline void write_3393_cmd(struct IN2000_hostdata *hostdata, uchar cmd)
{
/*   while (READ_AUX_STAT() & ASR_CIP)
      printk("|");*/
        write1_io(WD_COMMAND, IO_WD_ADDR);
        write1_io(cmd, IO_WD_DATA);
}


static uchar read_1_byte(struct IN2000_hostdata *hostdata)
{
        uchar asr, x = 0;

        write_3393(hostdata, WD_CONTROL, CTRL_IDI | CTRL_EDI | CTRL_POLLED);
        write_3393_cmd(hostdata, WD_CMD_TRANS_INFO | 0x80);
        do {
                asr = READ_AUX_STAT();
                if (asr & ASR_DBR)
                        x = read_3393(hostdata, WD_DATA);
        } while (!(asr & ASR_INT));
        return x;
}


static void write_3393_count(struct IN2000_hostdata *hostdata, unsigned long value)
{
        write1_io(WD_TRANSFER_COUNT_MSB, IO_WD_ADDR);
        write1_io((value >> 16), IO_WD_DATA);
        write1_io((value >> 8), IO_WD_DATA);
        write1_io(value, IO_WD_DATA);
}


static unsigned long read_3393_count(struct IN2000_hostdata *hostdata)
{
        unsigned long value;

        write1_io(WD_TRANSFER_COUNT_MSB, IO_WD_ADDR);
        value = read1_io(IO_WD_DATA) << 16;
        value |= read1_io(IO_WD_DATA) << 8;
        value |= read1_io(IO_WD_DATA);
        return value;
}


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



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

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

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

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

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



static void in2000_execute(struct Scsi_Host *instance);

static int in2000_queuecommand(Scsi_Cmnd * cmd, void (*done) (Scsi_Cmnd *))
{
        struct Scsi_Host *instance;
        struct IN2000_hostdata *hostdata;
        Scsi_Cmnd *tmp;

        instance = cmd->device->host;
        hostdata = (struct IN2000_hostdata *) instance->hostdata;

        DB(DB_QUEUE_COMMAND, scmd_printk(KERN_DEBUG, cmd, "Q-%02x-%ld(", cmd->cmnd[0], cmd->serial_number))

/* Set up a few fields in the Scsi_Cmnd structure for our own use:
 *  - host_scribble is the pointer to the next cmd in the input queue
 *  - scsi_done points to the routine we call when a cmd is finished
 *  - result is what you'd expect
 */
            cmd->host_scribble = NULL;
        cmd->scsi_done = done;
        cmd->result = 0;

/* We use the Scsi_Pointer structure that's included with each command
 * as a scratchpad (as it's intended to be used!). The handy thing about
 * the SCp.xxx fields is that they're always associated with a given
 * cmd, and are preserved across disconnect-reselect. This means we
 * can pretty much ignore SAVE_POINTERS and RESTORE_POINTERS messages
 * if we keep all the critical pointers and counters in SCp:
 *  - SCp.ptr is the pointer into the RAM buffer
 *  - SCp.this_residual is the size of that buffer
 *  - SCp.buffer points to the current scatter-gather buffer
 *  - SCp.buffers_residual tells us how many S.G. buffers there are
 *  - SCp.have_data_in helps keep track of >2048 byte transfers
 *  - SCp.sent_command is not used
 *  - SCp.phase records this command's SRCID_ER bit setting
 */

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

/* We don't set SCp.phase here - that's done in in2000_execute() */

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

        cmd->SCp.Status = ILLEGAL_STATUS_BYTE;

/* We need to disable interrupts before messing with the input
 * queue and calling in2000_execute().
 */

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

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

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

        in2000_execute(cmd->device->host);

        DB(DB_QUEUE_COMMAND, printk(")Q-%ld ", cmd->serial_number))
            return 0;
}



/*
 * This routine attempts to start a scsi command. If the host_card is
 * already connected, we give up immediately. Otherwise, look through
 * the input_Q, using the first command we find that's intended
 * for a currently non-busy target/lun.
 * Note that this function is always called with interrupts already
 * disabled (either from in2000_queuecommand() or in2000_intr()).
 */
static void in2000_execute(struct Scsi_Host *instance)
{
        struct IN2000_hostdata *hostdata;
        Scsi_Cmnd *cmd, *prev;
        int i;
        unsigned short *sp;
        unsigned short f;
        unsigned short flushbuf[16];


        hostdata = (struct IN2000_hostdata *) instance->hostdata;

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

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

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

                    return;
        }

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

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

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

        if (!cmd) {

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

                    return;
        }

        /*  remove command from queue */

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

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

/*
 * Start the selection process
 */

        if (is_dir_out(cmd))
                write_3393(hostdata, WD_DESTINATION_ID, cmd->device->id);
        else
                write_3393(hostdata, WD_DESTINATION_ID, cmd->device->id | DSTID_DPD);

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

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

      yes:
        cmd->SCp.phase = 1;

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

      no:
        write_3393(hostdata, WD_SOURCE_ID, ((cmd->SCp.phase) ? SRCID_ER : 0));

        write_3393(hostdata, WD_TARGET_LUN, cmd->device->lun);
        write_3393(hostdata, WD_SYNCHRONOUS_TRANSFER, hostdata->sync_xfer[cmd->device->id]);
        hostdata->busy[cmd->device->id] |= (1 << cmd->device->lun);

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

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

                hostdata->selecting = cmd;

/* Every target has its own synchronous transfer setting, kept in
 * the sync_xfer array, and a corresponding status byte in sync_stat[].
 * Each target's sync_stat[] entry is initialized to SS_UNSET, and its
 * sync_xfer[] entry is initialized to the default/safe value. SS_UNSET
 * means that the parameters are undetermined as yet, and that we
 * need to send an SDTR message to this device after selection is
 * complete. We set SS_FIRST to tell the interrupt routine to do so,
 * unless we don't want to even _try_ synchronous transfers: In this
 * case we set SS_SET to make the defaults final.
 */
                if (hostdata->sync_stat[cmd->device->id] == SS_UNSET) {
                        if (hostdata->sync_off & (1 << cmd->device->id))
                                hostdata->sync_stat[cmd->device->id] = SS_SET;
                        else
                                hostdata->sync_stat[cmd->device->id] = SS_FIRST;
                }
                hostdata->state = S_SELECTING;
                write_3393_count(hostdata, 0);  /* this guarantees a DATA_PHASE interrupt */
                write_3393_cmd(hostdata, WD_CMD_SEL_ATN);
        }

        else {

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

                hostdata->connected = cmd;
                write_3393(hostdata, WD_COMMAND_PHASE, 0);

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

                write1_io(WD_CDB_1, IO_WD_ADDR);
                for (i = 0; i < cmd->cmd_len; i++)
                        write1_io(cmd->cmnd[i], IO_WD_DATA);

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

                write_3393(hostdata, WD_OWN_ID, cmd->cmd_len);

                /* When doing a non-disconnect command, we can save ourselves a DATA
                 * phase interrupt later by setting everything up now. With writes we
                 * need to pre-fill the fifo; if there's room for the 32 flush bytes,
                 * put them in there too - that'll avoid a fifo interrupt. Reads are
                 * somewhat simpler.
                 * KLUDGE NOTE: It seems that you can't completely fill the fifo here:
                 * This results in the IO_FIFO_COUNT register rolling over to zero,
                 * and apparently the gate array logic sees this as empty, not full,
                 * so the 3393 chip is never signalled to start reading from the
                 * fifo. Or maybe it's seen as a permanent fifo interrupt condition.
                 * Regardless, we fix this by temporarily pretending that the fifo
                 * is 16 bytes smaller. (I see now that the old driver has a comment
                 * about "don't fill completely" in an analogous place - must be the
                 * same deal.) This results in CDROM, swap partitions, and tape drives
                 * needing an extra interrupt per write command - I think we can live
                 * with that!
                 */

                if (!(cmd->SCp.phase)) {
                        write_3393_count(hostdata, cmd->SCp.this_residual);
                        write_3393(hostdata, WD_CONTROL, CTRL_IDI | CTRL_EDI | CTRL_BUS);
                        write1_io(0, IO_FIFO_WRITE);    /* clear fifo counter, write mode */

                        if (is_dir_out(cmd)) {
                                hostdata->fifo = FI_FIFO_WRITING;
                                if ((i = cmd->SCp.this_residual) > (IN2000_FIFO_SIZE - 16))
                                        i = IN2000_FIFO_SIZE - 16;
                                cmd->SCp.have_data_in = i;      /* this much data in fifo */
                                i >>= 1;        /* Gulp. Assuming modulo 2. */
                                sp = (unsigned short *) cmd->SCp.ptr;
                                f = hostdata->io_base + IO_FIFO;

#ifdef FAST_WRITE_IO

                                FAST_WRITE2_IO();
#else
                                while (i--)
                                        write2_io(*sp++, IO_FIFO);

#endif

                                /* Is there room for the flush bytes? */

                                if (cmd->SCp.have_data_in <= ((IN2000_FIFO_SIZE - 16) - 32)) {
                                        sp = flushbuf;
                                        i = 16;

#ifdef FAST_WRITE_IO

                                        FAST_WRITE2_IO();
#else
                                        while (i--)
                                                write2_io(0, IO_FIFO);

#endif

                                }
                        }

                        else {
                                write1_io(0, IO_FIFO_READ);     /* put fifo in read mode */
                                hostdata->fifo = FI_FIFO_READING;
                                cmd->SCp.have_data_in = 0;      /* nothing transferred yet */
                        }

                } else {
                        write_3393_count(hostdata, 0);  /* this guarantees a DATA_PHASE interrupt */
                }
                hostdata->state = S_RUNNING_LEVEL2;
                write_3393_cmd(hostdata, WD_CMD_SEL_ATN_XFER);
        }

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

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

}



static void transfer_pio(uchar * buf, int cnt, int data_in_dir, struct IN2000_hostdata *hostdata)
{
        uchar asr;

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

            write_3393(hostdata, WD_CONTROL, CTRL_IDI | CTRL_EDI | CTRL_POLLED);
        write_3393_count(hostdata, cnt);
        write_3393_cmd(hostdata, WD_CMD_TRANS_INFO);
        if (data_in_dir) {
                do {
                        asr = READ_AUX_STAT();
                        if (asr & ASR_DBR)
                                *buf++ = read_3393(hostdata, WD_DATA);
                } while (!(asr & ASR_INT));
        } else {
                do {
                        asr = READ_AUX_STAT();
                        if (asr & ASR_DBR)
                                write_3393(hostdata, WD_DATA, *buf++);
                } while (!(asr & ASR_INT));
        }

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

}



static void transfer_bytes(Scsi_Cmnd * cmd, int data_in_dir)
{
        struct IN2000_hostdata *hostdata;
        unsigned short *sp;
        unsigned short f;
        int i;

        hostdata = (struct IN2000_hostdata *) cmd->device->host->hostdata;

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

/* Set up hardware registers */

        write_3393(hostdata, WD_SYNCHRONOUS_TRANSFER, hostdata->sync_xfer[cmd->device->id]);
        write_3393_count(hostdata, cmd->SCp.this_residual);
        write_3393(hostdata, WD_CONTROL, CTRL_IDI | CTRL_EDI | CTRL_BUS);
        write1_io(0, IO_FIFO_WRITE);    /* zero counter, assume write */

/* Reading is easy. Just issue the command and return - we'll
 * get an interrupt later when we have actual data to worry about.
 */

        if (data_in_dir) {
                write1_io(0, IO_FIFO_READ);
                if ((hostdata->level2 >= L2_DATA) || (hostdata->level2 == L2_BASIC && cmd->SCp.phase == 0)) {
                        write_3393(hostdata, WD_COMMAND_PHASE, 0x45);
                        write_3393_cmd(hostdata, WD_CMD_SEL_ATN_XFER);
                        hostdata->state = S_RUNNING_LEVEL2;
                } else
                        write_3393_cmd(hostdata, WD_CMD_TRANS_INFO);
                hostdata->fifo = FI_FIFO_READING;
                cmd->SCp.have_data_in = 0;
                return;
        }

/* Writing is more involved - we'll start the WD chip and write as
 * much data to the fifo as we can right now. Later interrupts will
 * write any bytes that don't make it at this stage.
 */

        if ((hostdata->level2 >= L2_DATA) || (hostdata->level2 == L2_BASIC && cmd->SCp.phase == 0)) {
                write_3393(hostdata, WD_COMMAND_PHASE, 0x45);
                write_3393_cmd(hostdata, WD_CMD_SEL_ATN_XFER);
                hostdata->state = S_RUNNING_LEVEL2;
        } else
                write_3393_cmd(hostdata, WD_CMD_TRANS_INFO);
        hostdata->fifo = FI_FIFO_WRITING;
        sp = (unsigned short *) cmd->SCp.ptr;

        if ((i = cmd->SCp.this_residual) > IN2000_FIFO_SIZE)
                i = IN2000_FIFO_SIZE;
        cmd->SCp.have_data_in = i;
        i >>= 1;                /* Gulp. We assume this_residual is modulo 2 */
        f = hostdata->io_base + IO_FIFO;

#ifdef FAST_WRITE_IO

        FAST_WRITE2_IO();
#else
        while (i--)
                write2_io(*sp++, IO_FIFO);

#endif

}


/* We need to use spin_lock_irqsave() & spin_unlock_irqrestore() in this
 * function in order to work in an SMP environment. (I'd be surprised
 * if the driver is ever used by anyone on a real multi-CPU motherboard,
 * but it _does_ need to be able to compile and run in an SMP kernel.)
 */

static irqreturn_t in2000_intr(int irqnum, void *dev_id)
{
        struct Scsi_Host *instance = dev_id;
        struct IN2000_hostdata *hostdata;
        Scsi_Cmnd *patch, *cmd;
        uchar asr, sr, phs, id, lun, *ucp, msg;
        int i, j;
        unsigned long length;
        unsigned short *sp;
        unsigned short f;
        unsigned long flags;

        hostdata = (struct IN2000_hostdata *) instance->hostdata;

/* Get the spin_lock and disable further ints, for SMP */

        spin_lock_irqsave(instance->host_lock, flags);

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

/* The IN2000 card has 2 interrupt sources OR'ed onto its IRQ line - the
 * WD3393 chip and the 2k fifo (which is actually a dual-port RAM combined
 * with a big logic array, so it's a little different than what you might
 * expect). As far as I know, there's no reason that BOTH can't be active
 * at the same time, but there's a problem: while we can read the 3393
 * to tell if _it_ wants an interrupt, I don't know of a way to ask the
 * fifo the same question. The best we can do is check the 3393 and if
 * it _isn't_ the source of the interrupt, then we can be pretty sure
 * that the fifo is the culprit.
 *  UPDATE: I have it on good authority (Bill Earnest) that bit 0 of the
 *          IO_FIFO_COUNT register mirrors the fifo interrupt state. I
 *          assume that bit clear means interrupt active. As it turns
 *          out, the driver really doesn't need to check for this after
 *          all, so my remarks above about a 'problem' can safely be
 *          ignored. The way the logic is set up, there's no advantage
 *          (that I can see) to worrying about it.
 *
 * It seems that the fifo interrupt signal is negated when we extract
 * bytes during read or write bytes during write.
 *  - fifo will interrupt when data is moving from it to the 3393, and
 *    there are 31 (or less?) bytes left to go. This is sort of short-
 *    sighted: what if you don't WANT to do more? In any case, our
 *    response is to push more into the fifo - either actual data or
 *    dummy bytes if need be. Note that we apparently have to write at
 *    least 32 additional bytes to the fifo after an interrupt in order
 *    to get it to release the ones it was holding on to - writing fewer
 *    than 32 will result in another fifo int.
 *  UPDATE: Again, info from Bill Earnest makes this more understandable:
 *          32 bytes = two counts of the fifo counter register. He tells
 *          me that the fifo interrupt is a non-latching signal derived
 *          from a straightforward boolean interpretation of the 7
 *          highest bits of the fifo counter and the fifo-read/fifo-write
 *          state. Who'd a thought?
 */

        write1_io(0, IO_LED_ON);
        asr = READ_AUX_STAT();
        if (!(asr & ASR_INT)) { /* no WD33c93 interrupt? */

/* Ok. This is definitely a FIFO-only interrupt.
 *
 * If FI_FIFO_READING is set, there are up to 2048 bytes waiting to be read,
 * maybe more to come from the SCSI bus. Read as many as we can out of the
 * fifo and into memory at the location of SCp.ptr[SCp.have_data_in], and
 * update have_data_in afterwards.
 *
 * If we have FI_FIFO_WRITING, the FIFO has almost run out of bytes to move
 * into the WD3393 chip (I think the interrupt happens when there are 31
 * bytes left, but it may be fewer...). The 3393 is still waiting, so we
 * shove some more into the fifo, which gets things moving again. If the
 * original SCSI command specified more than 2048 bytes, there may still
 * be some of that data left: fine - use it (from SCp.ptr[SCp.have_data_in]).
 * Don't forget to update have_data_in. If we've already written out the
 * entire buffer, feed 32 dummy bytes to the fifo - they're needed to
 * push out the remaining real data.
 *    (Big thanks to Bill Earnest for getting me out of the mud in here.)
 */

                cmd = (Scsi_Cmnd *) hostdata->connected;        /* assume we're connected */
                CHECK_NULL(cmd, "fifo_int")

                    if (hostdata->fifo == FI_FIFO_READING) {

                        DB(DB_FIFO, printk("{R:%02x} ", read1_io(IO_FIFO_COUNT)))

                            sp = (unsigned short *) (cmd->SCp.ptr + cmd->SCp.have_data_in);
                        i = read1_io(IO_FIFO_COUNT) & 0xfe;
                        i <<= 2;        /* # of words waiting in the fifo */
                        f = hostdata->io_base + IO_FIFO;

#ifdef FAST_READ_IO

                        FAST_READ2_IO();
#else
                        while (i--)
                                *sp++ = read2_io(IO_FIFO);

#endif

                        i = sp - (unsigned short *) (cmd->SCp.ptr + cmd->SCp.have_data_in);
                        i <<= 1;
                        cmd->SCp.have_data_in += i;
                }

                else if (hostdata->fifo == FI_FIFO_WRITING) {

                        DB(DB_FIFO, printk("{W:%02x} ", read1_io(IO_FIFO_COUNT)))

/* If all bytes have been written to the fifo, flush out the stragglers.
 * Note that while writing 16 dummy words seems arbitrary, we don't
 * have another choice that I can see. What we really want is to read
 * the 3393 transfer count register (that would tell us how many bytes
 * needed flushing), but the TRANSFER_INFO command hasn't completed
 * yet (not enough bytes!) and that register won't be accessible. So,
 * we use 16 words - a number obtained through trial and error.
 *  UPDATE: Bill says this is exactly what Always does, so there.
 *          More thanks due him for help in this section.
 */
                            if (cmd->SCp.this_residual == cmd->SCp.have_data_in) {
                                i = 16;
                                while (i--)     /* write 32 dummy bytes */
                                        write2_io(0, IO_FIFO);
                        }

/* If there are still bytes left in the SCSI buffer, write as many as we
 * can out to the fifo.
 */

                        else {
                                sp = (unsigned short *) (cmd->SCp.ptr + cmd->SCp.have_data_in);
                                i = cmd->SCp.this_residual - cmd->SCp.have_data_in;     /* bytes yet to go */
                                j = read1_io(IO_FIFO_COUNT) & 0xfe;
                                j <<= 2;        /* how many words the fifo has room for */
                                if ((j << 1) > i)
                                        j = (i >> 1);
                                while (j--)
                                        write2_io(*sp++, IO_FIFO);

                                i = sp - (unsigned short *) (cmd->SCp.ptr + cmd->SCp.have_data_in);
                                i <<= 1;
                                cmd->SCp.have_data_in += i;
                        }
                }

                else {
                        printk("*** Spurious FIFO interrupt ***");
                }

                write1_io(0, IO_LED_OFF);

/* release the SMP spin_lock and restore irq state */
                spin_unlock_irqrestore(instance->host_lock, flags);
                return IRQ_HANDLED;
        }

/* This interrupt was triggered by the WD33c93 chip. The fifo interrupt
 * may also be asserted, but we don't bother to check it: we get more
 * detailed info from FIFO_READING and FIFO_WRITING (see below).
 */

        cmd = (Scsi_Cmnd *) hostdata->connected;        /* assume we're connected */
        sr = read_3393(hostdata, WD_SCSI_STATUS);       /* clear the interrupt */
        phs = read_3393(hostdata, WD_COMMAND_PHASE);

        if (!cmd && (sr != CSR_RESEL_AM && sr != CSR_TIMEOUT && sr != CSR_SELECT)) {
                printk("\nNR:wd-intr-1\n");
                write1_io(0, IO_LED_OFF);

/* release the SMP spin_lock and restore irq state */
                spin_unlock_irqrestore(instance->host_lock, flags);
                return IRQ_HANDLED;
        }

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

/* After starting a FIFO-based transfer, the next _WD3393_ interrupt is
 * guaranteed to be in response to the completion of the transfer.
 * If we were reading, there's probably data in the fifo that needs
 * to be copied into RAM - do that here. Also, we have to update
 * 'this_residual' and 'ptr' based on the contents of the
 * TRANSFER_COUNT register, in case the device decided to do an
 * intermediate disconnect (a device may do this if it has to
 * do a seek,  or just to be nice and let other devices have
 * some bus time during long transfers).
 * After doing whatever is necessary with the fifo, we go on and
 * service the WD3393 interrupt normally.
 */
            if (hostdata->fifo == FI_FIFO_READING) {

/* buffer index = start-of-buffer + #-of-bytes-already-read */

                sp = (unsigned short *) (cmd->SCp.ptr + cmd->SCp.have_data_in);

/* bytes remaining in fifo = (total-wanted - #-not-got) - #-already-read */

                i = (cmd->SCp.this_residual - read_3393_count(hostdata)) - cmd->SCp.have_data_in;
                i >>= 1;        /* Gulp. We assume this will always be modulo 2 */
                f = hostdata->io_base + IO_FIFO;

#ifdef FAST_READ_IO

                FAST_READ2_IO();
#else
                while (i--)
                        *sp++ = read2_io(IO_FIFO);

#endif

                hostdata->fifo = FI_FIFO_UNUSED;
                length = cmd->SCp.this_residual;
                cmd->SCp.this_residual = read_3393_count(hostdata);
                cmd->SCp.ptr += (length - cmd->SCp.this_residual);

                DB(DB_TRANSFER, printk("(%p,%d)", cmd->SCp.ptr, cmd->SCp.this_residual))

        }

        else if (hostdata->fifo == FI_FIFO_WRITING) {
                hostdata->fifo = FI_FIFO_UNUSED;
                length = cmd->SCp.this_residual;
                cmd->SCp.this_residual = read_3393_count(hostdata);
                cmd->SCp.ptr += (length - cmd->SCp.this_residual);

                DB(DB_TRANSFER, printk("(%p,%d)", cmd->SCp.ptr, cmd->SCp.this_residual))

        }

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

        switch (sr) {

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

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

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

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

                in2000_execute(instance);
                break;


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

        case CSR_SELECT:
                DB(DB_INTR, printk("SELECT"))
                    hostdata->connected = cmd = (Scsi_Cmnd *) hostdata->selecting;
                CHECK_NULL(cmd, "csr_select")
                    hostdata->selecting = NULL;

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

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

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

                        hostdata->sync_stat[cmd->device->id] = SS_WAITING;

                        /* tack on a 2nd message to ask about synchronous transfers */

                        hostdata->outgoing_msg[1] = EXTENDED_MESSAGE;
                        hostdata->outgoing_msg[2] = 3;
                        hostdata->outgoing_msg[3] = EXTENDED_SDTR;
                        hostdata->outgoing_msg[4] = OPTIMUM_SX_PER / 4;
                        hostdata->outgoing_msg[5] = OPTIMUM_SX_OFF;
                        hostdata->outgoing_len = 6;
                } else
                        hostdata->outgoing_len = 1;

                hostdata->state = S_CONNECTED;
                break;


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


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


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

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


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

                    cmd->SCp.Status = read_1_byte(hostdata);
                DB(DB_INTR, printk("%02x", cmd->SCp.Status))
                    if (hostdata->level2 >= L2_BASIC) {
                        sr = read_3393(hostdata, WD_SCSI_STATUS);       /* clear interrupt */
                        hostdata->state = S_RUNNING_LEVEL2;
                        write_3393(hostdata, WD_COMMAND_PHASE, 0x50);
                        write_3393_cmd(hostdata, WD_CMD_SEL_ATN_XFER);
                } else {
                        hostdata->state = S_CONNECTED;
                }
                break;


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

                    msg = read_1_byte(hostdata);
                sr = read_3393(hostdata, WD_SCSI_STATUS);       /* clear interrupt */

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

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

                case COMMAND_COMPLETE:
                        DB(DB_INTR, printk("CCMP-%ld", cmd->serial_number))
                            write_3393_cmd(hostdata, WD_CMD_NEGATE_ACK);
                        hostdata->state = S_PRE_CMP_DISC;
                        break;

                case SAVE_POINTERS:
                        DB(DB_INTR, printk("SDP"))
                            write_3393_cmd(hostdata, WD_CMD_NEGATE_ACK);
                        hostdata->state = S_CONNECTED;
                        break;

                case RESTORE_POINTERS:
                        DB(DB_INTR, printk("RDP"))
                            if (hostdata->level2 >= L2_BASIC) {
                                write_3393(hostdata, WD_COMMAND_PHASE, 0x45);
                                write_3393_cmd(hostdata, WD_CMD_SEL_ATN_XFER);
                                hostdata->state = S_RUNNING_LEVEL2;
                        } else {
                                write_3393_cmd(hostdata, WD_CMD_NEGATE_ACK);
                                hostdata->state = S_CONNECTED;
                        }
                        break;

                case DISCONNECT:
                        DB(DB_INTR, printk("DIS"))
                            cmd->device->disconnect = 1;
                        write_3393_cmd(hostdata, WD_CMD_NEGATE_ACK);
                        hostdata->state = S_PRE_TMP_DISC;
                        break;

                case MESSAGE_REJECT:
                        DB(DB_INTR, printk("REJ"))
#ifdef SYNC_DEBUG
                            printk("-REJ-");
#endif
                        if (hostdata->sync_stat[cmd->device->id] == SS_WAITING)
                                hostdata->sync_stat[cmd->device->id] = SS_SET;
                        write_3393_cmd(hostdata, WD_CMD_NEGATE_ACK);
                        hostdata->state = S_CONNECTED;
                        break;

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

                            ucp = hostdata->incoming_msg;

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

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

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

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

                                                write_3393_cmd(hostdata, WD_CMD_ASSERT_ATN);    /* want MESS_OUT */
                                                hostdata->outgoing_msg[0] = EXTENDED_MESSAGE;
                                                hostdata->outgoing_msg[1] = 3;
                                                hostdata->outgoing_msg[2] = EXTENDED_SDTR;
                                                hostdata->outgoing_msg[3] = hostdata->default_sx_per / 4;
                                                hostdata->outgoing_msg[4] = 0;
                                                hostdata->outgoing_len = 5;
                                                hostdata->sync_xfer[cmd->device->id] = calc_sync_xfer(hostdata->default_sx_per / 4, 0);
                                        } else {
                                                hostdata->sync_xfer[cmd->device->id] = id;
                                        }
#ifdef SYNC_DEBUG
                                        printk("sync_xfer=%02x", hostdata->sync_xfer[cmd->device->id]);
#endif
                                        hostdata->sync_stat[cmd->device->id] = SS_SET;
                                        write_3393_cmd(hostdata, WD_CMD_NEGATE_ACK);
                                        hostdata->state = S_CONNECTED;
                                        break;
                                case EXTENDED_WDTR:
                                        write_3393_cmd(hostdata, WD_CMD_ASSERT_ATN);    /* want MESS_OUT */
                                        printk("sending WDTR ");
                                        hostdata->outgoing_msg[0] = EXTENDED_MESSAGE;
                                        hostdata->outgoing_msg[1] = 2;
                                        hostdata->outgoing_msg[2] = EXTENDED_WDTR;
                                        hostdata->outgoing_msg[3] = 0;  /* 8 bit transfer width */
                                        hostdata->outgoing_len = 4;
                                        write_3393_cmd(hostdata, WD_CMD_NEGATE_ACK);
                                        hostdata->state = S_CONNECTED;
                                        break;
                                default:
                                        write_3393_cmd(hostdata, WD_CMD_ASSERT_ATN);    /* want MESS_OUT */
                                        printk("Rejecting Unknown Extended Message(%02x). ", ucp[2]);
                                        hostdata->outgoing_msg[0] = MESSAGE_REJECT;
                                        hostdata->outgoing_len = 1;
                                        write_3393_cmd(hostdata, WD_CMD_NEGATE_ACK);
                                        hostdata->state = S_CONNECTED;
                                        break;
                                }
                                hostdata->incoming_ptr = 0;
                        }

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

                        else {
                                hostdata->incoming_ptr++;
                                write_3393_cmd(hostdata, WD_CMD_NEGATE_ACK);
                                hostdata->state = S_CONNECTED;
                        }
                        break;

                default:
                        printk("Rejecting Unknown Message(%02x) ", msg);
                        write_3393_cmd(hostdata, WD_CMD_ASSERT_ATN);    /* want MESS_OUT */
                        hostdata->outgoing_msg[0] = MESSAGE_REJECT;
                        hostdata->outgoing_len = 1;
                        write_3393_cmd(hostdata, WD_CMD_NEGATE_ACK);
                        hostdata->state = S_CONNECTED;
                }
                break;


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

        case CSR_SEL_XFER_DONE:

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

                write_3393(hostdata, WD_SOURCE_ID, SRCID_ER);
                if (phs == 0x60) {
                        DB(DB_INTR, printk("SX-DONE-%ld", cmd->serial_number))
                            cmd->SCp.Message = COMMAND_COMPLETE;
                        lun = read_3393(hostdata, WD_TARGET_LUN);
                        DB(DB_INTR, printk(":%d.%d", cmd->SCp.Status, lun))
                            hostdata->connected = NULL;
                        hostdata->busy[cmd->device->id] &= ~(1 << cmd->device->lun);
                        hostdata->state = S_UNCONNECTED;
                        if (cmd->SCp.Status == ILLEGAL_STATUS_BYTE)
                                cmd->SCp.Status = lun;
                        if (cmd->cmnd[0] == REQUEST_SENSE && cmd->SCp.Status != GOOD)
                                cmd->result = (cmd->result & 0x00ffff) | (DID_ERROR << 16);
                        else
                                cmd->result = cmd->SCp.Status | (cmd->SCp.Message << 8);
                        cmd->scsi_done(cmd);

/* We are no longer connected to a target - check to see if
 * there are commands waiting to be executed.
 */

                        in2000_execute(instance);
                } else {
                        printk("%02x:%02x:%02x-%ld: Unknown SEL_XFER_DONE phase!!---", asr, sr, phs, cmd->serial_number);
                }
                break;


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

        case CSR_SDP:
                DB(DB_INTR, printk("SDP"))
                    hostdata->state = S_RUNNING_LEVEL2;
                write_3393(hostdata, WD_COMMAND_PHASE, 0x41);
                write_3393_cmd(hostdata, WD_CMD_SEL_ATN_XFER);
                break;


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

/* To get here, we've probably requested MESSAGE_OUT and have
 * already put the correct bytes in outgoing_msg[] and filled
 * in outgoing_len. We simply send them out to the SCSI bus.
 * Sometimes we get MESSAGE_OUT phase when we're not expecting
 * it - like when our SDTR message is rejected by a target. Some
 * targets send the REJECT before receiving all of the extended
 * message, and then seem to go back to MESSAGE_OUT for a byte
 * or two. Not sure why, or if I'm doing something wrong to
 * cause this to happen. Regardless, it seems that sending
 * NOP messages in these situations results in no harm and
 * makes everyone happy.
 */
                    if (hostdata->outgoing_len == 0) {
                        hostdata->outgoing_len = 1;
                        hostdata->outgoing_msg[0] = NOP;
                }
                transfer_pio(hostdata->outgoing_msg, hostdata->outgoing_len, DATA_OUT_DIR, hostdata);
                DB(DB_INTR, printk("%02x", hostdata->outgoing_msg[0]))
                    hostdata->outgoing_len = 0;
                hostdata->state = S_CONNECTED;
                break;


        case CSR_UNEXP_DISC:

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


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

                write_3393(hostdata, WD_SOURCE_ID, SRCID_ER);
                if (cmd == NULL) {
                        printk(" - Already disconnected! ");
                        hostdata->state = S_UNCONNECTED;

/* release the SMP spin_lock and restore irq state */
                        spin_unlock_irqrestore(instance->host_lock, flags);
                        return IRQ_HANDLED;
                }
                DB(DB_INTR, printk("UNEXP_DISC-%ld", cmd->serial_number))
                    hostdata->connected = NULL;
                hostdata->busy[cmd->device->id] &= ~(1 << cmd->device->lun);
                hostdata->state = S_UNCONNECTED;
                if (cmd->cmnd[0] == REQUEST_SENSE && cmd->SCp.Status != GOOD)
                        cmd->result = (cmd->result & 0x00ffff) | (DID_ERROR << 16);
                else
                        cmd->result = cmd->SCp.Status | (cmd->SCp.Message << 8);
                cmd->scsi_done(cmd);

/* We are no longer connected to a target - check to see if
 * there are commands waiting to be executed.
 */

                in2000_execute(instance);
                break;


        case CSR_DISC:

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

                write_3393(hostdata, WD_SOURCE_ID, SRCID_ER);
                DB(DB_INTR, printk("DISC-%ld", cmd->serial_number))
                    if (cmd == NULL) {
                        printk(" - Already disconnected! ");
                        hostdata->state = S_UNCONNECTED;
                }
                switch (hostdata->state) {
                case S_PRE_CMP_DISC:
                        hostdata->connected = NULL;
                        hostdata->busy[cmd->device->id] &= ~(1 << cmd->device->lun);
                        hostdata->state = S_UNCONNECTED;
                        DB(DB_INTR, printk(":%d", cmd->SCp.Status))
                            if (cmd->cmnd[0] == REQUEST_SENSE && cmd->SCp.Status != GOOD)
                                cmd->result = (cmd->result & 0x00ffff) | (DID_ERROR << 16);
                        else
                                cmd->result = cmd->SCp.Status | (cmd->SCp.Message << 8);
                        cmd->scsi_done(cmd);
                        break;
                case S_PRE_TMP_DISC:
                case S_RUNNING_LEVEL2:
                        cmd->host_scribble = (uchar *) hostdata->disconnected_Q;
                        hostdata->disconnected_Q = cmd;
                        hostdata->connected = NULL;
                        hostdata->state = S_UNCONNECTED;

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

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

/* We are no longer connected to a target - check to see if
 * there are commands waiting to be executed.
 */

                in2000_execute(instance);
                break;


        case CSR_RESEL_AM:
                DB(DB_INTR, printk("RESEL"))

                    /* First we have to make sure this reselection didn't */
                    /* happen during Arbitration/Selection of some other device. */
                    /* If yes, put losing command back on top of input_Q. */
                    if (hostdata->level2 <= L2_NONE) {

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

                else {

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

                }

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

                id = read_3393(hostdata, WD_SOURCE_ID);
                id &= SRCID_MASK;

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

                lun = read_3393(hostdata, WD_DATA);
                if (hostdata->level2 < L2_RESELECT)
                        write_3393_cmd(hostdata, WD_CMD_NEGATE_ACK);
                lun &= 7;

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

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

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

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

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

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

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

                if (is_dir_out(cmd))
                        write_3393(hostdata, WD_DESTINATION_ID, cmd->device->id);
                else
                        write_3393(hostdata, WD_DESTINATION_ID, cmd->device->id | DSTID_DPD);
                if (hostdata->level2 >= L2_RESELECT) {
                        write_3393_count(hostdata, 0);  /* we want a DATA_PHASE interrupt */
                        write_3393(hostdata, WD_COMMAND_PHASE, 0x45);
                        write_3393_cmd(hostdata, WD_CMD_SEL_ATN_XFER);
                        hostdata->state = S_RUNNING_LEVEL2;
                } else
                        hostdata->state = S_CONNECTED;

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

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

        write1_io(0, IO_LED_OFF);

        DB(DB_INTR, printk("} "))

/* release the SMP spin_lock and restore irq state */
            spin_unlock_irqrestore(instance->host_lock, flags);
        return IRQ_HANDLED;
}



#define RESET_CARD         0
#define RESET_CARD_AND_BUS 1
#define B_FLAG 0x80

/*
 *      Caller must hold instance lock!
 */

static int reset_hardware(struct Scsi_Host *instance, int type)
{
        struct IN2000_hostdata *hostdata;
        int qt, x;

        hostdata = (struct IN2000_hostdata *) instance->hostdata;

        write1_io(0, IO_LED_ON);
        if (type == RESET_CARD_AND_BUS) {
                write1_io(0, IO_CARD_RESET);
                x = read1_io(IO_HARDWARE);
        }
        x = read_3393(hostdata, WD_SCSI_STATUS);        /* clear any WD intrpt */
        write_3393(hostdata, WD_OWN_ID, instance->this_id | OWNID_EAF | OWNID_RAF | OWNID_FS_8);
        write_3393(hostdata, WD_CONTROL, CTRL_IDI | CTRL_EDI | CTRL_POLLED);
        write_3393(hostdata, WD_SYNCHRONOUS_TRANSFER, calc_sync_xfer(hostdata->default_sx_per / 4, DEFAULT_SX_OFF));

        write1_io(0, IO_FIFO_WRITE);    /* clear fifo counter */
        write1_io(0, IO_FIFO_READ);     /* start fifo out in read mode */
        write_3393(hostdata, WD_COMMAND, WD_CMD_RESET);
        /* FIXME: timeout ?? */
        while (!(READ_AUX_STAT() & ASR_INT))
                cpu_relax();    /* wait for RESET to complete */

        x = read_3393(hostdata, WD_SCSI_STATUS);        /* clear interrupt */

        write_3393(hostdata, WD_QUEUE_TAG, 0xa5);       /* any random number */
        qt = read_3393(hostdata, WD_QUEUE_TAG);
        if (qt == 0xa5) {
                x |= B_FLAG;
                write_3393(hostdata, WD_QUEUE_TAG, 0);
        }
        write_3393(hostdata, WD_TIMEOUT_PERIOD, TIMEOUT_PERIOD_VALUE);
        write_3393(hostdata, WD_CONTROL, CTRL_IDI | CTRL_EDI | CTRL_POLLED);
        write1_io(0, IO_LED_OFF);
        return x;
}



static int in2000_bus_reset(Scsi_Cmnd * cmd)
{
        struct Scsi_Host *instance;
        struct IN2000_hostdata *hostdata;
        int x;
        unsigned long flags;

        instance = cmd->device->host;
        hostdata = (struct IN2000_hostdata *) instance->hostdata;

        printk(KERN_WARNING "scsi%d: Reset. ", instance->host_no);

        spin_lock_irqsave(instance->host_lock, flags);

        /* do scsi-reset here */
        reset_hardware(instance, RESET_CARD_AND_BUS);
        for (x = 0; x < 8; x++) {
                hostdata->busy[x] = 0;
                hostdata->sync_xfer[x] = calc_sync_xfer(DEFAULT_SX_PER / 4, DEFAULT_SX_OFF);
                hostdata->sync_stat[x] = SS_UNSET;      /* using default sync values */
        }
        hostdata->input_Q = NULL;
        hostdata->selecting = NULL;
        hostdata->connected = NULL;
        hostdata->disconnected_Q = NULL;
        hostdata->state = S_UNCONNECTED;
        hostdata->fifo = FI_FIFO_UNUSED;
        hostdata->incoming_ptr = 0;
        hostdata->outgoing_len = 0;

        cmd->result = DID_RESET << 16;

        spin_unlock_irqrestore(instance->host_lock, flags);
        return SUCCESS;
}

static int __in2000_abort(Scsi_Cmnd * cmd)
{
        struct Scsi_Host *instance;
        struct IN2000_hostdata *hostdata;
        Scsi_Cmnd *tmp, *prev;
        uchar sr, asr;
        unsigned long timeout;

        instance = cmd->device->host;
        hostdata = (struct IN2000_hostdata *) instance->hostdata;

        printk(KERN_DEBUG "scsi%d: Abort-", instance->host_no);
        printk("(asr=%02x,count=%ld,resid=%d,buf_resid=%d,have_data=%d,FC=%02x)- ", READ_AUX_STAT(), read_3393_count(hostdata), cmd->SCp.this_residual, cmd->SCp.buffers_residual, cmd->SCp.have_data_in, read1_io(IO_FIFO_COUNT));

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

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

/*
 * Case 2 : If the command is connected, we're going to fail the abort
 *     and let the high level SCSI driver retry at a later time or
 *     issue a reset.
 *
 *     Timeouts, and therefore aborted commands, will be highly unlikely
 *     and handling them cleanly in this situation would make the common
 *     case of noresets less efficient, and would pollute our code.  So,
 *     we fail.
 */

        if (hostdata->connected == cmd) {

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

                printk("sending wd33c93 ABORT command - ");
                write_3393(hostdata, WD_CONTROL, CTRL_IDI | CTRL_EDI | CTRL_POLLED);
                write_3393_cmd(hostdata, WD_CMD_ABORT);

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

                printk("flushing fifo - ");
                timeout = 1000000;
                do {
                        asr = READ_AUX_STAT();
                        if (asr & ASR_DBR)
                                read_3393(hostdata, WD_DATA);
                } while (!(asr & ASR_INT) && timeout-- > 0);
                sr = read_3393(hostdata, WD_SCSI_STATUS);
                printk("asr=%02x, sr=%02x, %ld bytes un-transferred (timeout=%ld) - ", asr, sr, read_3393_count(hostdata), timeout);

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

                printk("sending wd33c93 DISCONNECT command - ");
                write_3393_cmd(hostdata, WD_CMD_DISCONNECT);

                timeout = 1000000;
                asr = READ_AUX_STAT();
                while ((asr & ASR_CIP) && timeout-- > 0)
                        asr = READ_AUX_STAT();
                sr = read_3393(hostdata, WD_SCSI_STATUS);
                printk("asr=%02x, sr=%02x.", asr, sr);

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

                in2000_execute(instance);

                return SUCCESS;
        }

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

        for (tmp = (Scsi_Cmnd *) hostdata->disconnected_Q; tmp; tmp = (Scsi_Cmnd *) tmp->host_scribble)
                if (cmd == tmp) {
                        printk(KERN_DEBUG "scsi%d: unable to abort disconnected command.\n", instance->host_no);
                        return FAILED;
                }

/*
 * Case 4 : If we reached this point, the command was not found in any of
 *     the queues.
 *
 * We probably reached this point because of an unlikely race condition
 * between the command completing successfully and the abortion code,
 * so we won't panic, but we will notify the user in case something really
 * broke.
 */

        in2000_execute(instance);

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

static int in2000_abort(Scsi_Cmnd * cmd)
{
        int rc;

        spin_lock_irq(cmd->device->host->host_lock);
        rc = __in2000_abort(cmd);
        spin_unlock_irq(cmd->device->host->host_lock);

        return rc;
}


#define MAX_IN2000_HOSTS 3
#define MAX_SETUP_ARGS ARRAY_SIZE(setup_args)
#define SETUP_BUFFER_SIZE 200
static char setup_buffer[SETUP_BUFFER_SIZE];
static char setup_used[MAX_SETUP_ARGS];
static int done_setup = 0;

static void __init in2000_setup(char *str, int *ints)
{
        int i;
        char *p1, *p2;

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


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

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

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



/* The "correct" (ie portable) way to access memory-mapped hardware
 * such as the IN2000 EPROM and dip switch is through the use of
 * special macros declared in 'asm/io.h'. We use readb() and readl()
 * when reading from the card's BIOS area in in2000_detect().
 */
static u32 bios_tab[] in2000__INITDATA = {
        0xc8000,
        0xd0000,
        0xd8000,
        0
};

static unsigned short base_tab[] in2000__INITDATA = {
        0x220,
        0x200,
        0x110,
        0x100,
};

static int int_tab[] in2000__INITDATA = {
        15,
        14,
        11,
        10
};

static int probe_bios(u32 addr, u32 *s1, uchar *switches)
{
        void __iomem *p = ioremap(addr, 0x34);
        if (!p)
                return 0;
        *s1 = readl(p + 0x10);
        if (*s1 == 0x41564f4e || readl(p + 0x30) == 0x61776c41) {
                /* Read the switch image that's mapped into EPROM space */
                *switches = ~readb(p + 0x20);
                iounmap(p);
                return 1;
        }
        iounmap(p);
        return 0;
}

static int __init in2000_detect(struct scsi_host_template * tpnt)
{
        struct Scsi_Host *instance;
        struct IN2000_hostdata *hostdata;
        int detect_count;
        int bios;
        int x;
        unsigned short base;
        uchar switches;
        uchar hrev;
        unsigned long flags;
        int val;
        char buf[32];

/* Thanks to help from Bill Earnest, probing for IN2000 cards is a
 * pretty straightforward and fool-proof operation. There are 3
 * possible locations for the IN2000 EPROM in memory space - if we
 * find a BIOS signature, we can read the dip switch settings from
 * the byte at BIOS+32 (shadowed in by logic on the card). From 2
 * of the switch bits we get the card's address in IO space. There's
 * an image of the dip switch there, also, so we have a way to back-
 * check that this really is an IN2000 card. Very nifty. Use the
 * 'ioport:xx' command-line parameter if your BIOS EPROM is absent
 * or disabled.
 */

        if (!done_setup && setup_strings)
                in2000_setup(setup_strings, NULL);

        detect_count = 0;
        for (bios = 0; bios_tab[bios]; bios++) {
                u32 s1 = 0;
                if (check_setup_args("ioport", &val, buf)) {
                        base = val;
                        switches = ~inb(base + IO_SWITCHES) & 0xff;
                        printk("Forcing IN2000 detection at IOport 0x%x ", base);
                        bios = 2;
                }
/*
 * There have been a couple of BIOS versions with different layouts
 * for the obvious ID strings. We look for the 2 most common ones and
 * hope that they cover all the cases...
 */
                else if (probe_bios(bios_tab[bios], &s1, &switches)) {
                        printk("Found IN2000 BIOS at 0x%x ", (unsigned int) bios_tab[bios]);

/* Find out where the IO space is */

                        x = switches & (SW_ADDR0 | SW_ADDR1);
                        base = base_tab[x];

/* Check for the IN2000 signature in IO space. */

                        x = ~inb(base + IO_SWITCHES) & 0xff;
                        if (x != switches) {
                                printk("Bad IO signature: %02x vs %02x.\n", x, switches);
                                continue;
                        }
                } else
                        continue;

/* OK. We have a base address for the IO ports - run a few safety checks */

                if (!(switches & SW_BIT7)) {    /* I _think_ all cards do this */
                        printk("There is no IN-2000 SCSI card at IOport 0x%03x!\n", base);
                        continue;
                }

/* Let's assume any hardware version will work, although the driver
 * has only been tested on 0x21, 0x22, 0x25, 0x26, and 0x27. We'll
 * print out the rev number for reference later, but accept them all.
 */

                hrev = inb(base + IO_HARDWARE);

                /* Bit 2 tells us if interrupts are disabled */
                if (switches & SW_DISINT) {
                        printk("The IN-2000 SCSI card at IOport 0x%03x ", base);
                        printk("is not configured for interrupt operation!\n");
                        printk("This driver requires an interrupt: cancelling detection.\n");
                        continue;
                }

/* Ok. We accept that there's an IN2000 at ioaddr 'base'. Now
 * initialize it.
 */

                tpnt->proc_name = "in2000";
                instance = scsi_register(tpnt, sizeof(struct IN2000_hostdata));
                if (instance == NULL)
                        continue;
                detect_count++;
                hostdata = (struct IN2000_hostdata *) instance->hostdata;
                instance->io_port = hostdata->io_base = base;
                hostdata->dip_switch = switches;
                hostdata->hrev = hrev;

                write1_io(0, IO_FIFO_WRITE);    /* clear fifo counter */
                write1_io(0, IO_FIFO_READ);     /* start fifo out in read mode */
                write1_io(0, IO_INTR_MASK);     /* allow all ints */
                x = int_tab[(switches & (SW_INT0 | SW_INT1)) >> SW_INT_SHIFT];
                if (request_irq(x, in2000_intr, IRQF_DISABLED, "in2000", instance)) {
                        printk("in2000_detect: Unable to allocate IRQ.\n");
                        detect_count--;
                        continue;
                }
                instance->irq = x;
                instance->n_io_port = 13;
                request_region(base, 13, "in2000");     /* lock in this IO space for our use */

                for (x = 0; x < 8; x++) {
                        hostdata->busy[x] = 0;
                        hostdata->sync_xfer[x] = calc_sync_xfer(DEFAULT_SX_PER / 4, DEFAULT_SX_OFF);
                        hostdata->sync_stat[x] = SS_UNSET;      /* using default sync values */
#ifdef PROC_STATISTICS
                        hostdata->cmd_cnt[x] = 0;
                        hostdata->disc_allowed_cnt[x] = 0;
                        hostdata->disc_done_cnt[x] = 0;
#endif
                }
                hostdata->input_Q = NULL;
                hostdata->selecting = NULL;
                hostdata->connected = NULL;
                hostdata->disconnected_Q = NULL;
                hostdata->state = S_UNCONNECTED;
                hostdata->fifo = FI_FIFO_UNUSED;
                hostdata->level2 = L2_BASIC;
                hostdata->disconnect = DIS_ADAPTIVE;
                hostdata->args = DEBUG_DEFAULTS;
                hostdata->incoming_ptr = 0;
                hostdata->outgoing_len = 0;
                hostdata->default_sx_per = DEFAULT_SX_PER;

/* Older BIOS's had a 'sync on/off' switch - use its setting */

                if (s1 == 0x41564f4e && (switches & SW_SYNC_DOS5))
                        hostdata->sync_off = 0x00;      /* sync defaults to on */
                else
                        hostdata->sync_off = 0xff;      /* sync defaults to off */

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

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

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

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

                if (check_setup_args("noreset", &val, buf))
                        hostdata->args ^= A_NO_SCSI_RESET;

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

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

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


                /* FIXME: not strictly needed I think but the called code expects
                   to be locked */
                spin_lock_irqsave(instance->host_lock, flags);
                x = reset_hardware(instance, (hostdata->args & A_NO_SCSI_RESET) ? RESET_CARD : RESET_CARD_AND_BUS);
                spin_unlock_irqrestore(instance->host_lock, flags);

                hostdata->microcode = read_3393(hostdata, WD_CDB_1);
                if (x & 0x01) {
                        if (x & B_FLAG)
                                hostdata->chip = C_WD33C93B;
                        else
                                hostdata->chip = C_WD33C93A;
                } else
                        hostdata->chip = C_WD33C93;

                printk("dip_switch=%02x irq=%d ioport=%02x floppy=%s sync/DOS5=%s ", (switches & 0x7f), instance->irq, hostdata->io_base, (switches & SW_FLOPPY) ? "Yes" : "No", (switches & SW_SYNC_DOS5) ? "Yes" : "No");
                printk("hardware_ver=%02x chip=%s microcode=%02x\n", hrev, (hostdata->chip == C_WD33C93) ? "WD33c93" : (hostdata->chip == C_WD33C93A) ? "WD33c93A" : (hostdata->chip == C_WD33C93B) ? "WD33c93B" : "unknown", hostdata->microcode);
#ifdef DEBUGGING_ON
                printk("setup_args = ");
                for (x = 0; x < MAX_SETUP_ARGS; x++)
                        printk("%s,", setup_args[x]);
                printk("\n");
#endif
                if (hostdata->sync_off == 0xff)
                        printk("Sync-transfer DISABLED on all devices: ENABLE from command-line\n");
                printk("IN2000 driver version %s - %s\n", IN2000_VERSION, IN2000_DATE);
        }

        return detect_count;
}

static int in2000_release(struct Scsi_Host *shost)
{
        if (shost->irq)
                free_irq(shost->irq, shost);
        if (shost->io_port && shost->n_io_port)
                release_region(shost->io_port, shost->n_io_port);
        return 0;
}

/* NOTE: I lifted this function straight out of the old driver,
 *       and have not tested it. Presumably it does what it's
 *       supposed to do...
 */

static int in2000_biosparam(struct scsi_device *sdev, struct block_device *bdev, sector_t capacity, int *iinfo)
{
        int size;

        size = capacity;
        iinfo[0] = 64;
        iinfo[1] = 32;
        iinfo[2] = size >> 11;

/* This should approximate the large drive handling that the DOS ASPI manager
   uses.  Drives very near the boundaries may not be handled correctly (i.e.
   near 2.0 Gb and 4.0 Gb) */

        if (iinfo[2] > 1024) {
                iinfo[0] = 64;
                iinfo[1] = 63;
                iinfo[2] = (unsigned long) capacity / (iinfo[0] * iinfo[1]);
        }
        if (iinfo[2] > 1024) {
                iinfo[0] = 128;
                iinfo[1] = 63;
                iinfo[2] = (unsigned long) capacity / (iinfo[0] * iinfo[1]);
        }
        if (iinfo[2] > 1024) {
                iinfo[0] = 255;
                iinfo[1] = 63;
                iinfo[2] = (unsigned long) capacity / (iinfo[0] * iinfo[1]);
        }
        return 0;
}


static int in2000_proc_info(struct Scsi_Host *instance, char *buf, char **start, off_t off, int len, int in)
{

#ifdef PROC_INTERFACE

        char *bp;
        char tbuf[128];
        unsigned long flags;
        struct IN2000_hostdata *hd;
        Scsi_Cmnd *cmd;
        int x, i;
        static int stop = 0;

        hd = (struct IN2000_hostdata *) instance->hostdata;

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

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

        spin_lock_irqsave(instance->host_lock, flags);
        bp = buf;
        *bp = '\0';
        if (hd->proc & PR_VERSION) {
                sprintf(tbuf, "\nVersion %s - %s. Compiled %s %s", IN2000_VERSION, IN2000_DATE, __DATE__, __TIME__);
                strcat(bp, tbuf);
        }
        if (hd->proc & PR_INFO) {
                sprintf(tbuf, "\ndip_switch=%02x: irq=%d io=%02x floppy=%s sync/DOS5=%s", (hd->dip_switch & 0x7f), instance->irq, hd->io_base, (hd->dip_switch & 0x40) ? "Yes" : "No", (hd->dip_switch & 0x20) ? "Yes" : "No");
                strcat(bp, tbuf);
                strcat(bp, "\nsync_xfer[] =       ");
                for (x = 0; x < 7; x++) {
                        sprintf(tbuf, "\t%02x", hd->sync_xfer[x]);
                        strcat(bp, tbuf);
                }
                strcat(bp, "\nsync_stat[] =       ");
                for (x = 0; x < 7; x++) {
                        sprintf(tbuf, "\t%02x", hd->sync_stat[x]);
                        strcat(bp, tbuf);
                }
        }
#ifdef PROC_STATISTICS
        if (hd->proc & PR_STATISTICS) {
                strcat(bp, "\ncommands issued:    ");
                for (x = 0; x < 7; x++) {
                        sprintf(tbuf, "\t%ld", hd->cmd_cnt[x]);
                        strcat(bp, tbuf);
                }
                strcat(bp, "\ndisconnects allowed:");
                for (x = 0; x < 7; x++) {
                        sprintf(tbuf, "\t%ld", hd->disc_allowed_cnt[x]);
                        strcat(bp, tbuf);
                }
                strcat(bp, "\ndisconnects done:   ");
                for (x = 0; x < 7; x++) {
                        sprintf(tbuf, "\t%ld", hd->disc_done_cnt[x]);
                        strcat(bp, tbuf);
                }
                sprintf(tbuf, "\ninterrupts:      \t%ld", hd->int_cnt);
                strcat(bp, tbuf);
        }
#endif
        if (hd->proc & PR_CONNECTED) {
                strcat(bp, "\nconnected:     ");
                if (hd->connected) {
                        cmd = (Scsi_Cmnd *) hd->connected;
                        sprintf(tbuf, " %ld-%d:%d(%02x)", cmd->serial_number, cmd->device->id, cmd->device->lun, cmd->cmnd[0]);
                        strcat(bp, tbuf);
                }
        }
        if (hd->proc & PR_INPUTQ) {
                strcat(bp, "\ninput_Q:       ");
                cmd = (Scsi_Cmnd *) hd->input_Q;
                while (cmd) {
                        sprintf(tbuf, " %ld-%d:%d(%02x)", cmd->serial_number, cmd->device->id, cmd->device->lun, cmd->cmnd[0]);
                        strcat(bp, tbuf);
                        cmd = (Scsi_Cmnd *) cmd->host_scribble;
                }
        }
        if (hd->proc & PR_DISCQ) {
                strcat(bp, "\ndisconnected_Q:");
                cmd = (Scsi_Cmnd *) hd->disconnected_Q;
                while (cmd) {
                        sprintf(tbuf, " %ld-%d:%d(%02x)", cmd->serial_number, cmd->device->id, cmd->device->lun, cmd->cmnd[0]);
                        strcat(bp, tbuf);
                        cmd = (Scsi_Cmnd *) cmd->host_scribble;
                }
        }
        if (hd->proc & PR_TEST) {
                ;               /* insert your own custom function here */
        }
        strcat(bp, "\n");
        spin_unlock_irqrestore(instance->host_lock, flags);
        *start = buf;
        if (stop) {
                stop = 0;
                return 0;       /* return 0 to signal end-of-file */
        }
        if (off > 0x40000)      /* ALWAYS stop after 256k bytes have been read */
                stop = 1;
        if (hd->proc & PR_STOP) /* stop every other time */
                stop = 1;
        return strlen(bp);

#else                           /* PROC_INTERFACE */

        return 0;

#endif                          /* PROC_INTERFACE */

}

MODULE_LICENSE("GPL");


static struct scsi_host_template driver_template = {
        .proc_name                      = "in2000",
        .proc_info                      = in2000_proc_info,
        .name                           = "Always IN2000",
        .detect                         = in2000_detect, 
        .release                        = in2000_release,
        .queuecommand                   = in2000_queuecommand,
        .eh_abort_handler               = in2000_abort,
        .eh_bus_reset_handler           = in2000_bus_reset,
        .bios_param                     = in2000_biosparam, 
        .can_queue                      = IN2000_CAN_Q,
        .this_id                        = IN2000_HOST_ID,
        .sg_tablesize                   = IN2000_SG,
        .cmd_per_lun                    = IN2000_CPL,
        .use_clustering                 = DISABLE_CLUSTERING,
};
#include "scsi_module.c"