/* $Id: $
 *  linux/drivers/scsi/wd7000.c
 *
 *  Copyright (C) 1992  Thomas Wuensche
 *      closely related to the aha1542 driver from Tommy Thorn
 *      ( as close as different hardware allows on a lowlevel-driver :-) )
 *
 *  Revised (and renamed) by John Boyd <boyd@cis.ohio-state.edu> to
 *  accommodate Eric Youngdale's modifications to scsi.c.  Nov 1992.
 *
 *  Additional changes to support scatter/gather.  Dec. 1992.  tw/jb
 *
 *  No longer tries to reset SCSI bus at boot (it wasn't working anyway).
 *  Rewritten to support multiple host adapters.
 *  Miscellaneous cleanup.
 *  So far, still doesn't do reset or abort correctly, since I have no idea
 *  how to do them with this board (8^(.                      Jan 1994 jb
 *
 * This driver now supports both of the two standard configurations (per
 * the 3.36 Owner's Manual, my latest reference) by the same method as
 * before; namely, by looking for a BIOS signature.  Thus, the location of
 * the BIOS signature determines the board configuration.  Until I have
 * time to do something more flexible, users should stick to one of the
 * following:
 *
 * Standard configuration for single-adapter systems:
 *    - BIOS at CE00h
 *    - I/O base address 350h
 *    - IRQ level 15
 *    - DMA channel 6
 * Standard configuration for a second adapter in a system:
 *    - BIOS at C800h
 *    - I/O base address 330h
 *    - IRQ level 11
 *    - DMA channel 5
 *
 * Anyone who can recompile the kernel is welcome to add others as need
 * arises, but unpredictable results may occur if there are conflicts.
 * In any event, if there are multiple adapters in a system, they MUST
 * use different I/O bases, IRQ levels, and DMA channels, since they will be
 * indistinguishable (and in direct conflict) otherwise.
 *
 *   As a point of information, the NO_OP command toggles the CMD_RDY bit
 * of the status port, and this fact could be used as a test for the I/O
 * base address (or more generally, board detection).  There is an interrupt
 * status port, so IRQ probing could also be done.  I suppose the full
 * DMA diagnostic could be used to detect the DMA channel being used.  I
 * haven't done any of this, though, because I think there's too much of
 * a chance that such explorations could be destructive, if some other
 * board's resources are used inadvertently.  So, call me a wimp, but I
 * don't want to try it.  The only kind of exploration I trust is memory
 * exploration, since it's more certain that reading memory won't be
 * destructive.
 *
 * More to my liking would be a LILO boot command line specification, such
 * as is used by the aha152x driver (and possibly others).  I'll look into
 * it, as I have time...
 *
 *   I get mail occasionally from people who either are using or are
 * considering using a WD7000 with Linux.  There is a variety of
 * nomenclature describing WD7000's.  To the best of my knowledge, the
 * following is a brief summary (from an old WD doc - I don't work for
 * them or anything like that):
 *
 * WD7000-FASST2: This is a WD7000 board with the real-mode SST ROM BIOS
 *        installed.  Last I heard, the BIOS was actually done by Columbia
 *        Data Products.  The BIOS is only used by this driver (and thus
 *        by Linux) to identify the board; none of it can be executed under
 *        Linux.
 *
 * WD7000-ASC: This is the original adapter board, with or without BIOS.
 *        The board uses a WD33C93 or WD33C93A SBIC, which in turn is
 *        controlled by an onboard Z80 processor.  The board interface
 *        visible to the host CPU is defined effectively by the Z80's
 *        firmware, and it is this firmware's revision level that is
 *        determined and reported by this driver.  (The version of the
 *        on-board BIOS is of no interest whatsoever.)  The host CPU has
 *        no access to the SBIC; hence the fact that it is a WD33C93 is
 *        also of no interest to this driver.
 *
 * WD7000-AX:
 * WD7000-MX:
 * WD7000-EX: These are newer versions of the WD7000-ASC.  The -ASC is
 *        largely built from discrete components; these boards use more
 *        integration.  The -AX is an ISA bus board (like the -ASC),
 *        the -MX is an MCA (i.e., PS/2) bus board), and the -EX is an
 *        EISA bus board.
 *
 *  At the time of my documentation, the -?X boards were "future" products,
 *  and were not yet available.  However, I vaguely recall that Thomas
 *  Wuensche had an -AX, so I believe at least it is supported by this
 *  driver.  I have no personal knowledge of either -MX or -EX boards.
 *
 *  P.S. Just recently, I've discovered (directly from WD and Future
 *  Domain) that all but the WD7000-EX have been out of production for
 *  two years now.  FD has production rights to the 7000-EX, and are
 *  producing it under a new name, and with a new BIOS.  If anyone has
 *  one of the FD boards, it would be nice to come up with a signature
 *  for it.
 *                                                           J.B. Jan 1994.
 *
 *
 *  Revisions by Miroslav Zagorac <zaga@fly.cc.fer.hr>
 *
 *  08/24/1996.
 *
 *  Enhancement for wd7000_detect function has been made, so you don't have
 *  to enter BIOS ROM address in initialisation data (see struct Config).
 *  We cannot detect IRQ, DMA and I/O base address for now, so we have to
 *  enter them as arguments while wd_7000 is detected. If someone has IRQ,
 *  DMA or I/O base address set to some other value, he can enter them in
 *  configuration without any problem. Also I wrote a function wd7000_setup,
 *  so now you can enter WD-7000 definition as kernel arguments,
 *  as in lilo.conf:
 *
 *     append="wd7000=IRQ,DMA,IO"
 *
 *  PS: If card BIOS ROM is disabled, function wd7000_detect now will recognize
 *      adapter, unlike the old one. Anyway, BIOS ROM from WD7000 adapter is
 *      useless for Linux. B^)
 *
 *
 *  09/06/1996.
 *
 *  Autodetecting of I/O base address from wd7000_detect function is removed,
 *  some little bugs removed, etc...
 *
 *  Thanks to Roger Scott for driver debugging.
 *
 *  06/07/1997
 *
 *  Added support for /proc file system (/proc/scsi/wd7000/[0...] files).
 *  Now, driver can handle hard disks with capacity >1GB.
 *
 *  01/15/1998
 *
 *  Added support for BUS_ON and BUS_OFF parameters in config line.
 *  Miscellaneous cleanup.
 *
 *  03/01/1998
 *
 *  WD7000 driver now work on kernels >= 2.1.x
 *
 *
 * 12/31/2001 - Arnaldo Carvalho de Melo <acme@conectiva.com.br>
 *
 * use host->host_lock, not io_request_lock, cleanups
 *
 * 2002/10/04 - Alan Cox <alan@lxorguk.ukuu.org.uk>
 *
 * Use dev_id for interrupts, kill __func__ pasting
 * Add a lock for the scb pool, clean up all other cli/sti usage stuff
 * Use the adapter lock for the other places we had the cli's
 *
 * 2002/10/06 - Alan Cox <alan@lxorguk.ukuu.org.uk>
 *
 * Switch to new style error handling
 * Clean up delay to udelay, and yielding sleeps
 * Make host reset actually reset the card
 * Make everything static
 *
 * 2003/02/12 - Christoph Hellwig <hch@infradead.org>
 *
 * Cleaned up host template defintion
 * Removed now obsolete wd7000.h
 */

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

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

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


#undef  WD7000_DEBUG            /* general debug                */
#ifdef WD7000_DEBUG
#define dprintk printk
#else
#define dprintk(format,args...)
#endif

/*
 *  Mailbox structure sizes.
 *  I prefer to keep the number of ICMBs much larger than the number of
 *  OGMBs.  OGMBs are used very quickly by the driver to start one or
 *  more commands, while ICMBs are used by the host adapter per command.
 */
#define OGMB_CNT        16
#define ICMB_CNT        32

/*
 *  Scb's are shared by all active adapters.  So, if they all become busy,
 *  callers may be made to wait in alloc_scbs for them to free.  That can
 *  be avoided by setting MAX_SCBS to NUM_CONFIG * WD7000_Q.  If you'd
 *  rather conserve memory, use a smaller number (> 0, of course) - things
 *  will should still work OK.
 */
#define MAX_SCBS        32

/*
 *  In this version, sg_tablesize now defaults to WD7000_SG, and will
 *  be set to SG_NONE for older boards.  This is the reverse of the
 *  previous default, and was changed so that the driver-level
 *  scsi_host_template would reflect the driver's support for scatter/
 *  gather.
 *
 *  Also, it has been reported that boards at Revision 6 support scatter/
 *  gather, so the new definition of an "older" board has been changed
 *  accordingly.
 */
#define WD7000_Q        16
#define WD7000_SG       16


/*
 *  WD7000-specific mailbox structure
 *
 */
typedef volatile struct mailbox {
        unchar status;
        unchar scbptr[3];       /* SCSI-style - MSB first (big endian) */
} Mailbox;

/*
 *  This structure should contain all per-adapter global data.  I.e., any
 *  new global per-adapter data should put in here.
 */
typedef struct adapter {
        struct Scsi_Host *sh;   /* Pointer to Scsi_Host structure    */
        int iobase;             /* This adapter's I/O base address   */
        int irq;                /* This adapter's IRQ level          */
        int dma;                /* This adapter's DMA channel        */
        int int_counter;        /* This adapter's interrupt counter  */
        int bus_on;             /* This adapter's BUS_ON time        */
        int bus_off;            /* This adapter's BUS_OFF time       */
        struct {                /* This adapter's mailboxes          */
                Mailbox ogmb[OGMB_CNT]; /* Outgoing mailboxes                */
                Mailbox icmb[ICMB_CNT]; /* Incoming mailboxes                */
        } mb;
        int next_ogmb;          /* to reduce contention at mailboxes */
        unchar control;         /* shadows CONTROL port value        */
        unchar rev1, rev2;      /* filled in by wd7000_revision      */
} Adapter;

/*
 * (linear) base address for ROM BIOS
 */
static const long wd7000_biosaddr[] = {
        0xc0000, 0xc2000, 0xc4000, 0xc6000, 0xc8000, 0xca000, 0xcc000, 0xce000,
        0xd0000, 0xd2000, 0xd4000, 0xd6000, 0xd8000, 0xda000, 0xdc000, 0xde000
};
#define NUM_ADDRS ARRAY_SIZE(wd7000_biosaddr)

static const unsigned short wd7000_iobase[] = {
        0x0300, 0x0308, 0x0310, 0x0318, 0x0320, 0x0328, 0x0330, 0x0338,
        0x0340, 0x0348, 0x0350, 0x0358, 0x0360, 0x0368, 0x0370, 0x0378,
        0x0380, 0x0388, 0x0390, 0x0398, 0x03a0, 0x03a8, 0x03b0, 0x03b8,
        0x03c0, 0x03c8, 0x03d0, 0x03d8, 0x03e0, 0x03e8, 0x03f0, 0x03f8
};
#define NUM_IOPORTS ARRAY_SIZE(wd7000_iobase)

static const short wd7000_irq[] = { 3, 4, 5, 7, 9, 10, 11, 12, 14, 15 };
#define NUM_IRQS ARRAY_SIZE(wd7000_irq)

static const short wd7000_dma[] = { 5, 6, 7 };
#define NUM_DMAS ARRAY_SIZE(wd7000_dma)

/*
 * The following is set up by wd7000_detect, and used thereafter for
 * proc and other global ookups
 */

#define UNITS   8
static struct Scsi_Host *wd7000_host[UNITS];

#define BUS_ON    64            /* x 125ns = 8000ns (BIOS default) */
#define BUS_OFF   15            /* x 125ns = 1875ns (BIOS default) */

/*
 *  Standard Adapter Configurations - used by wd7000_detect
 */
typedef struct {
        short irq;              /* IRQ level                                  */
        short dma;              /* DMA channel                                */
        unsigned iobase;        /* I/O base address                           */
        short bus_on;           /* Time that WD7000 spends on the AT-bus when */
        /* transferring data. BIOS default is 8000ns. */
        short bus_off;          /* Time that WD7000 spends OFF THE BUS after  */
        /* while it is transferring data.             */
        /* BIOS default is 1875ns                     */
} Config;

/*
 * Add here your configuration...
 */
static Config configs[] = {
        {15, 6, 0x350, BUS_ON, BUS_OFF},        /* defaults for single adapter */
        {11, 5, 0x320, BUS_ON, BUS_OFF},        /* defaults for second adapter */
        {7, 6, 0x350, BUS_ON, BUS_OFF}, /* My configuration (Zaga)     */
        {-1, -1, 0x0, BUS_ON, BUS_OFF}  /* Empty slot                  */
};
#define NUM_CONFIGS ARRAY_SIZE(configs)

/*
 *  The following list defines strings to look for in the BIOS that identify
 *  it as the WD7000-FASST2 SST BIOS.  I suspect that something should be
 *  added for the Future Domain version.
 */
typedef struct signature {
        const char *sig;        /* String to look for            */
        unsigned long ofs;      /* offset from BIOS base address */
        unsigned len;           /* length of string              */
} Signature;

static const Signature signatures[] = {
        {"SSTBIOS", 0x0000d, 7} /* "SSTBIOS" @ offset 0x0000d */
};
#define NUM_SIGNATURES ARRAY_SIZE(signatures)


/*
 *  I/O Port Offsets and Bit Definitions
 *  4 addresses are used.  Those not defined here are reserved.
 */
#define ASC_STAT        0       /* Status,  Read          */
#define ASC_COMMAND     0       /* Command, Write         */
#define ASC_INTR_STAT   1       /* Interrupt Status, Read */
#define ASC_INTR_ACK    1       /* Acknowledge, Write     */
#define ASC_CONTROL     2       /* Control, Write         */

/*
 * ASC Status Port
 */
#define INT_IM          0x80    /* Interrupt Image Flag           */
#define CMD_RDY         0x40    /* Command Port Ready             */
#define CMD_REJ         0x20    /* Command Port Byte Rejected     */
#define ASC_INIT        0x10    /* ASC Initialized Flag           */
#define ASC_STATMASK    0xf0    /* The lower 4 Bytes are reserved */

/*
 * COMMAND opcodes
 *
 *  Unfortunately, I have no idea how to properly use some of these commands,
 *  as the OEM manual does not make it clear.  I have not been able to use
 *  enable/disable unsolicited interrupts or the reset commands with any
 *  discernible effect whatsoever.  I think they may be related to certain
 *  ICB commands, but again, the OEM manual doesn't make that clear.
 */
#define NO_OP             0     /* NO-OP toggles CMD_RDY bit in ASC_STAT  */
#define INITIALIZATION    1     /* initialization (10 bytes)              */
#define DISABLE_UNS_INTR  2     /* disable unsolicited interrupts         */
#define ENABLE_UNS_INTR   3     /* enable unsolicited interrupts          */
#define INTR_ON_FREE_OGMB 4     /* interrupt on free OGMB                 */
#define SOFT_RESET        5     /* SCSI bus soft reset                    */
#define HARD_RESET_ACK    6     /* SCSI bus hard reset acknowledge        */
#define START_OGMB        0x80  /* start command in OGMB (n)              */
#define SCAN_OGMBS        0xc0  /* start multiple commands, signature (n) */
                                /*    where (n) = lower 6 bits            */
/*
 * For INITIALIZATION:
 */
typedef struct initCmd {
        unchar op;              /* command opcode (= 1)                    */
        unchar ID;              /* Adapter's SCSI ID                       */
        unchar bus_on;          /* Bus on time, x 125ns (see below)        */
        unchar bus_off;         /* Bus off time, ""         ""             */
        unchar rsvd;            /* Reserved                                */
        unchar mailboxes[3];    /* Address of Mailboxes, MSB first         */
        unchar ogmbs;           /* Number of outgoing MBs, max 64, 0,1 = 1 */
        unchar icmbs;           /* Number of incoming MBs,   ""       ""   */
} InitCmd;

/*
 * Interrupt Status Port - also returns diagnostic codes at ASC reset
 *
 * if msb is zero, the lower bits are diagnostic status
 * Diagnostics:
 * 01   No diagnostic error occurred
 * 02   RAM failure
 * 03   FIFO R/W failed
 * 04   SBIC register read/write failed
 * 05   Initialization D-FF failed
 * 06   Host IRQ D-FF failed
 * 07   ROM checksum error
 * Interrupt status (bitwise):
 * 10NNNNNN   outgoing mailbox NNNNNN is free
 * 11NNNNNN   incoming mailbox NNNNNN needs service
 */
#define MB_INTR    0xC0         /* Mailbox Service possible/required */
#define IMB_INTR   0x40         /* 1 Incoming / 0 Outgoing           */
#define MB_MASK    0x3f         /* mask for mailbox number           */

/*
 * CONTROL port bits
 */
#define INT_EN     0x08         /* Interrupt Enable */
#define DMA_EN     0x04         /* DMA Enable       */
#define SCSI_RES   0x02         /* SCSI Reset       */
#define ASC_RES    0x01         /* ASC Reset        */

/*
 * Driver data structures:
 *   - mb and scbs are required for interfacing with the host adapter.
 *     An SCB has extra fields not visible to the adapter; mb's
 *     _cannot_ do this, since the adapter assumes they are contiguous in
 *     memory, 4 bytes each, with ICMBs following OGMBs, and uses this fact
 *     to access them.
 *   - An icb is for host-only (non-SCSI) commands.  ICBs are 16 bytes each;
 *     the additional bytes are used only by the driver.
 *   - For now, a pool of SCBs are kept in global storage by this driver,
 *     and are allocated and freed as needed.
 *
 *  The 7000-FASST2 marks OGMBs empty as soon as it has _started_ a command,
 *  not when it has finished.  Since the SCB must be around for completion,
 *  problems arise when SCBs correspond to OGMBs, which may be reallocated
 *  earlier (or delayed unnecessarily until a command completes).
 *  Mailboxes are used as transient data structures, simply for
 *  carrying SCB addresses to/from the 7000-FASST2.
 *
 *  Note also since SCBs are not "permanently" associated with mailboxes,
 *  there is no need to keep a global list of scsi_cmnd pointers indexed
 *  by OGMB.   Again, SCBs reference their scsi_cmnds directly, so mailbox
 *  indices need not be involved.
 */

/*
 *  WD7000-specific scatter/gather element structure
 */
typedef struct sgb {
        unchar len[3];
        unchar ptr[3];          /* Also SCSI-style - MSB first */
} Sgb;

typedef struct scb {            /* Command Control Block 5.4.1               */
        unchar op;              /* Command Control Block Operation Code      */
        unchar idlun;           /* op=0,2:Target Id, op=1:Initiator Id       */
        /* Outbound data transfer, length is checked */
        /* Inbound data transfer, length is checked  */
        /* Logical Unit Number                       */
        unchar cdb[12];         /* SCSI Command Block                        */
        volatile unchar status; /* SCSI Return Status                        */
        volatile unchar vue;    /* Vendor Unique Error Code                  */
        unchar maxlen[3];       /* Maximum Data Transfer Length              */
        unchar dataptr[3];      /* SCSI Data Block Pointer                   */
        unchar linkptr[3];      /* Next Command Link Pointer                 */
        unchar direc;           /* Transfer Direction                        */
        unchar reserved2[6];    /* SCSI Command Descriptor Block             */
        /* end of hardware SCB                       */
        struct scsi_cmnd *SCpnt;/* scsi_cmnd using this SCB                  */
        Sgb sgb[WD7000_SG];     /* Scatter/gather list for this SCB          */
        Adapter *host;          /* host adapter                              */
        struct scb *next;       /* for lists of scbs                         */
} Scb;

/*
 *  This driver is written to allow host-only commands to be executed.
 *  These use a 16-byte block called an ICB.  The format is extended by the
 *  driver to 18 bytes, to support the status returned in the ICMB and
 *  an execution phase code.
 *
 *  There are other formats besides these; these are the ones I've tried
 *  to use.  Formats for some of the defined ICB opcodes are not defined
 *  (notably, get/set unsolicited interrupt status) in my copy of the OEM
 *  manual, and others are ambiguous/hard to follow.
 */
#define ICB_OP_MASK           0x80      /* distinguishes scbs from icbs        */
#define ICB_OP_OPEN_RBUF      0x80      /* open receive buffer                 */
#define ICB_OP_RECV_CMD       0x81      /* receive command from initiator      */
#define ICB_OP_RECV_DATA      0x82      /* receive data from initiator         */
#define ICB_OP_RECV_SDATA     0x83      /* receive data with status from init. */
#define ICB_OP_SEND_DATA      0x84      /* send data with status to initiator  */
#define ICB_OP_SEND_STAT      0x86      /* send command status to initiator    */
                                        /* 0x87 is reserved                    */
#define ICB_OP_READ_INIT      0x88      /* read initialization bytes           */
#define ICB_OP_READ_ID        0x89      /* read adapter's SCSI ID              */
#define ICB_OP_SET_UMASK      0x8A      /* set unsolicited interrupt mask      */
#define ICB_OP_GET_UMASK      0x8B      /* read unsolicited interrupt mask     */
#define ICB_OP_GET_REVISION   0x8C      /* read firmware revision level        */
#define ICB_OP_DIAGNOSTICS    0x8D      /* execute diagnostics                 */
#define ICB_OP_SET_EPARMS     0x8E      /* set execution parameters            */
#define ICB_OP_GET_EPARMS     0x8F      /* read execution parameters           */

typedef struct icbRecvCmd {
        unchar op;
        unchar IDlun;           /* Initiator SCSI ID/lun     */
        unchar len[3];          /* command buffer length     */
        unchar ptr[3];          /* command buffer address    */
        unchar rsvd[7];         /* reserved                  */
        volatile unchar vue;    /* vendor-unique error code  */
        volatile unchar status; /* returned (icmb) status    */
        volatile unchar phase;  /* used by interrupt handler */
} IcbRecvCmd;

typedef struct icbSendStat {
        unchar op;
        unchar IDlun;           /* Target SCSI ID/lun                  */
        unchar stat;            /* (outgoing) completion status byte 1 */
        unchar rsvd[12];        /* reserved                            */
        volatile unchar vue;    /* vendor-unique error code            */
        volatile unchar status; /* returned (icmb) status              */
        volatile unchar phase;  /* used by interrupt handler           */
} IcbSendStat;

typedef struct icbRevLvl {
        unchar op;
        volatile unchar primary;        /* primary revision level (returned)   */
        volatile unchar secondary;      /* secondary revision level (returned) */
        unchar rsvd[12];        /* reserved                            */
        volatile unchar vue;    /* vendor-unique error code            */
        volatile unchar status; /* returned (icmb) status              */
        volatile unchar phase;  /* used by interrupt handler           */
} IcbRevLvl;

typedef struct icbUnsMask {     /* I'm totally guessing here */
        unchar op;
        volatile unchar mask[14];       /* mask bits                 */
#if 0
        unchar rsvd[12];        /* reserved                  */
#endif
        volatile unchar vue;    /* vendor-unique error code  */
        volatile unchar status; /* returned (icmb) status    */
        volatile unchar phase;  /* used by interrupt handler */
} IcbUnsMask;

typedef struct icbDiag {
        unchar op;
        unchar type;            /* diagnostics type code (0-3) */
        unchar len[3];          /* buffer length               */
        unchar ptr[3];          /* buffer address              */
        unchar rsvd[7];         /* reserved                    */
        volatile unchar vue;    /* vendor-unique error code    */
        volatile unchar status; /* returned (icmb) status      */
        volatile unchar phase;  /* used by interrupt handler   */
} IcbDiag;

#define ICB_DIAG_POWERUP   0    /* Power-up diags only       */
#define ICB_DIAG_WALKING   1    /* walking 1's pattern       */
#define ICB_DIAG_DMA       2    /* DMA - system memory diags */
#define ICB_DIAG_FULL      3    /* do both 1 & 2             */

typedef struct icbParms {
        unchar op;
        unchar rsvd1;           /* reserved                  */
        unchar len[3];          /* parms buffer length       */
        unchar ptr[3];          /* parms buffer address      */
        unchar idx[2];          /* index (MSB-LSB)           */
        unchar rsvd2[5];        /* reserved                  */
        volatile unchar vue;    /* vendor-unique error code  */
        volatile unchar status; /* returned (icmb) status    */
        volatile unchar phase;  /* used by interrupt handler */
} IcbParms;

typedef struct icbAny {
        unchar op;
        unchar data[14];        /* format-specific data      */
        volatile unchar vue;    /* vendor-unique error code  */
        volatile unchar status; /* returned (icmb) status    */
        volatile unchar phase;  /* used by interrupt handler */
} IcbAny;

typedef union icb {
        unchar op;              /* ICB opcode                     */
        IcbRecvCmd recv_cmd;    /* format for receive command     */
        IcbSendStat send_stat;  /* format for send status         */
        IcbRevLvl rev_lvl;      /* format for get revision level  */
        IcbDiag diag;           /* format for execute diagnostics */
        IcbParms eparms;        /* format for get/set exec parms  */
        IcbAny icb;             /* generic format                 */
        unchar data[18];
} Icb;

#ifdef MODULE
static char *wd7000;
module_param(wd7000, charp, 0);
#endif

/*
 *  Driver SCB structure pool.
 *
 *  The SCBs declared here are shared by all host adapters; hence, this
 *  structure is not part of the Adapter structure.
 */
static Scb scbs[MAX_SCBS];
static Scb *scbfree;            /* free list         */
static int freescbs = MAX_SCBS; /* free list counter */
static spinlock_t scbpool_lock; /* guards the scb free list and count */

/*
 *  END of data/declarations - code follows.
 */
static void __init setup_error(char *mesg, int *ints)
{
        if (ints[0] == 3)
                printk(KERN_ERR "wd7000_setup: \"wd7000=%d,%d,0x%x\" -> %s\n", ints[1], ints[2], ints[3], mesg);
        else if (ints[0] == 4)
                printk(KERN_ERR "wd7000_setup: \"wd7000=%d,%d,0x%x,%d\" -> %s\n", ints[1], ints[2], ints[3], ints[4], mesg);
        else
                printk(KERN_ERR "wd7000_setup: \"wd7000=%d,%d,0x%x,%d,%d\" -> %s\n", ints[1], ints[2], ints[3], ints[4], ints[5], mesg);
}


/*
 * Note: You can now set these options from the kernel's "command line".
 * The syntax is:
 *
 *     wd7000=<IRQ>,<DMA>,<IO>[,<BUS_ON>[,<BUS_OFF>]]
 *
 * , where BUS_ON and BUS_OFF are in nanoseconds. BIOS default values
 * are 8000ns for BUS_ON and 1875ns for BUS_OFF.
 * eg:
 *     wd7000=7,6,0x350
 *
 * will configure the driver for a WD-7000 controller
 * using IRQ 15 with a DMA channel 6, at IO base address 0x350.
 */
static int __init wd7000_setup(char *str)
{
        static short wd7000_card_num;   /* .bss will zero this */
        short i;
        int ints[6];

        (void) get_options(str, ARRAY_SIZE(ints), ints);

        if (wd7000_card_num >= NUM_CONFIGS) {
                printk(KERN_ERR "%s: Too many \"wd7000=\" configurations in " "command line!\n", __func__);
                return 0;
        }

        if ((ints[0] < 3) || (ints[0] > 5)) {
                printk(KERN_ERR "%s: Error in command line!  " "Usage: wd7000=<IRQ>,<DMA>,IO>[,<BUS_ON>" "[,<BUS_OFF>]]\n", __func__);
        } else {
                for (i = 0; i < NUM_IRQS; i++)
                        if (ints[1] == wd7000_irq[i])
                                break;

                if (i == NUM_IRQS) {
                        setup_error("invalid IRQ.", ints);
                        return 0;
                } else
                        configs[wd7000_card_num].irq = ints[1];

                for (i = 0; i < NUM_DMAS; i++)
                        if (ints[2] == wd7000_dma[i])
                                break;

                if (i == NUM_DMAS) {
                        setup_error("invalid DMA channel.", ints);
                        return 0;
                } else
                        configs[wd7000_card_num].dma = ints[2];

                for (i = 0; i < NUM_IOPORTS; i++)
                        if (ints[3] == wd7000_iobase[i])
                                break;

                if (i == NUM_IOPORTS) {
                        setup_error("invalid I/O base address.", ints);
                        return 0;
                } else
                        configs[wd7000_card_num].iobase = ints[3];

                if (ints[0] > 3) {
                        if ((ints[4] < 500) || (ints[4] > 31875)) {
                                setup_error("BUS_ON value is out of range (500" " to 31875 nanoseconds)!", ints);
                                configs[wd7000_card_num].bus_on = BUS_ON;
                        } else
                                configs[wd7000_card_num].bus_on = ints[4] / 125;
                } else
                        configs[wd7000_card_num].bus_on = BUS_ON;

                if (ints[0] > 4) {
                        if ((ints[5] < 500) || (ints[5] > 31875)) {
                                setup_error("BUS_OFF value is out of range (500" " to 31875 nanoseconds)!", ints);
                                configs[wd7000_card_num].bus_off = BUS_OFF;
                        } else
                                configs[wd7000_card_num].bus_off = ints[5] / 125;
                } else
                        configs[wd7000_card_num].bus_off = BUS_OFF;

                if (wd7000_card_num) {
                        for (i = 0; i < (wd7000_card_num - 1); i++) {
                                int j = i + 1;

                                for (; j < wd7000_card_num; j++)
                                        if (configs[i].irq == configs[j].irq) {
                                                setup_error("duplicated IRQ!", ints);
                                                return 0;
                                        }
                                if (configs[i].dma == configs[j].dma) {
                                        setup_error("duplicated DMA " "channel!", ints);
                                        return 0;
                                }
                                if (configs[i].iobase == configs[j].iobase) {
                                        setup_error("duplicated I/O " "base address!", ints);
                                        return 0;
                                }
                        }
                }

                dprintk(KERN_DEBUG "wd7000_setup: IRQ=%d, DMA=%d, I/O=0x%x, "
                        "BUS_ON=%dns, BUS_OFF=%dns\n", configs[wd7000_card_num].irq, configs[wd7000_card_num].dma, configs[wd7000_card_num].iobase, configs[wd7000_card_num].bus_on * 125, configs[wd7000_card_num].bus_off * 125);

                wd7000_card_num++;
        }
        return 1;
}

__setup("wd7000=", wd7000_setup);

static inline void any2scsi(unchar * scsi, int any)
{
        *scsi++ = (unsigned)any >> 16;
        *scsi++ = (unsigned)any >> 8;
        *scsi++ = any;
}

static inline int scsi2int(unchar * scsi)
{
        return (scsi[0] << 16) | (scsi[1] << 8) | scsi[2];
}

static inline void wd7000_enable_intr(Adapter * host)
{
        host->control |= INT_EN;
        outb(host->control, host->iobase + ASC_CONTROL);
}


static inline void wd7000_enable_dma(Adapter * host)
{
        unsigned long flags;
        host->control |= DMA_EN;
        outb(host->control, host->iobase + ASC_CONTROL);

        flags = claim_dma_lock();
        set_dma_mode(host->dma, DMA_MODE_CASCADE);
        enable_dma(host->dma);
        release_dma_lock(flags);

}


#define WAITnexttimeout 200     /* 2 seconds */

static inline short WAIT(unsigned port, unsigned mask, unsigned allof, unsigned noneof)
{
        unsigned WAITbits;
        unsigned long WAITtimeout = jiffies + WAITnexttimeout;

        while (time_before_eq(jiffies, WAITtimeout)) {
                WAITbits = inb(port) & mask;

                if (((WAITbits & allof) == allof) && ((WAITbits & noneof) == 0))
                        return (0);
        }

        return (1);
}


static inline int command_out(Adapter * host, unchar * cmd, int len)
{
        if (!WAIT(host->iobase + ASC_STAT, ASC_STATMASK, CMD_RDY, 0)) {
                while (len--) {
                        do {
                                outb(*cmd, host->iobase + ASC_COMMAND);
                                WAIT(host->iobase + ASC_STAT, ASC_STATMASK, CMD_RDY, 0);
                        } while (inb(host->iobase + ASC_STAT) & CMD_REJ);

                        cmd++;
                }

                return (1);
        }

        printk(KERN_WARNING "wd7000 command_out: WAIT failed(%d)\n", len + 1);

        return (0);
}


/*
 *  This version of alloc_scbs is in preparation for supporting multiple
 *  commands per lun and command chaining, by queueing pending commands.
 *  We will need to allocate Scbs in blocks since they will wait to be
 *  executed so there is the possibility of deadlock otherwise.
 *  Also, to keep larger requests from being starved by smaller requests,
 *  we limit access to this routine with an internal busy flag, so that
 *  the satisfiability of a request is not dependent on the size of the
 *  request.
 */
static inline Scb *alloc_scbs(struct Scsi_Host *host, int needed)
{
        Scb *scb, *p = NULL;
        unsigned long flags;
        unsigned long timeout = jiffies + WAITnexttimeout;
        unsigned long now;
        int i;

        if (needed <= 0)
                return (NULL);  /* sanity check */

        spin_unlock_irq(host->host_lock);

      retry:
        while (freescbs < needed) {
                timeout = jiffies + WAITnexttimeout;
                do {
                        /* FIXME: can we actually just yield here ?? */
                        for (now = jiffies; now == jiffies;)
                                cpu_relax();    /* wait a jiffy */
                } while (freescbs < needed && time_before_eq(jiffies, timeout));
                /*
                 *  If we get here with enough free Scbs, we can take them.
                 *  Otherwise, we timed out and didn't get enough.
                 */
                if (freescbs < needed) {
                        printk(KERN_ERR "wd7000: can't get enough free SCBs.\n");
                        return (NULL);
                }
        }

        /* Take the lock, then check we didnt get beaten, if so try again */
        spin_lock_irqsave(&scbpool_lock, flags);
        if (freescbs < needed) {
                spin_unlock_irqrestore(&scbpool_lock, flags);
                goto retry;
        }

        scb = scbfree;
        freescbs -= needed;
        for (i = 0; i < needed; i++) {
                p = scbfree;
                scbfree = p->next;
        }
        p->next = NULL;

        spin_unlock_irqrestore(&scbpool_lock, flags);

        spin_lock_irq(host->host_lock);
        return (scb);
}


static inline void free_scb(Scb * scb)
{
        unsigned long flags;

        spin_lock_irqsave(&scbpool_lock, flags);

        memset(scb, 0, sizeof(Scb));
        scb->next = scbfree;
        scbfree = scb;
        freescbs++;

        spin_unlock_irqrestore(&scbpool_lock, flags);
}


static inline void init_scbs(void)
{
        int i;

        spin_lock_init(&scbpool_lock);

        /* This is only ever called before the SCB pool is active */

        scbfree = &(scbs[0]);
        memset(scbs, 0, sizeof(scbs));
        for (i = 0; i < MAX_SCBS - 1; i++) {
                scbs[i].next = &(scbs[i + 1]);
                scbs[i].SCpnt = NULL;
        }
        scbs[MAX_SCBS - 1].next = NULL;
        scbs[MAX_SCBS - 1].SCpnt = NULL;
}


static int mail_out(Adapter * host, Scb * scbptr)
/*
 *  Note: this can also be used for ICBs; just cast to the parm type.
 */
{
        int i, ogmb;
        unsigned long flags;
        unchar start_ogmb;
        Mailbox *ogmbs = host->mb.ogmb;
        int *next_ogmb = &(host->next_ogmb);

        dprintk("wd7000_mail_out: 0x%06lx", (long) scbptr);

        /* We first look for a free outgoing mailbox */
        spin_lock_irqsave(host->sh->host_lock, flags);
        ogmb = *next_ogmb;
        for (i = 0; i < OGMB_CNT; i++) {
                if (ogmbs[ogmb].status == 0) {
                        dprintk(" using OGMB 0x%x", ogmb);
                        ogmbs[ogmb].status = 1;
                        any2scsi((unchar *) ogmbs[ogmb].scbptr, (int) scbptr);

                        *next_ogmb = (ogmb + 1) % OGMB_CNT;
                        break;
                } else
                        ogmb = (ogmb + 1) % OGMB_CNT;
        }
        spin_unlock_irqrestore(host->sh->host_lock, flags);

        dprintk(", scb is 0x%06lx", (long) scbptr);

        if (i >= OGMB_CNT) {
                /*
                 *  Alternatively, we might issue the "interrupt on free OGMB",
                 *  and sleep, but it must be ensured that it isn't the init
                 *  task running.  Instead, this version assumes that the caller
                 *  will be persistent, and try again.  Since it's the adapter
                 *  that marks OGMB's free, waiting even with interrupts off
                 *  should work, since they are freed very quickly in most cases.
                 */
                dprintk(", no free OGMBs.\n");
                return (0);
        }

        wd7000_enable_intr(host);

        start_ogmb = START_OGMB | ogmb;
        command_out(host, &start_ogmb, 1);

        dprintk(", awaiting interrupt.\n");

        return (1);
}


static int make_code(unsigned hosterr, unsigned scsierr)
{
#ifdef WD7000_DEBUG
        int in_error = hosterr;
#endif

        switch ((hosterr >> 8) & 0xff) {
        case 0:         /* Reserved */
                hosterr = DID_ERROR;
                break;
        case 1:         /* Command Complete, no errors */
                hosterr = DID_OK;
                break;
        case 2:         /* Command complete, error logged in scb status (scsierr) */
                hosterr = DID_OK;
                break;
        case 4:         /* Command failed to complete - timeout */
                hosterr = DID_TIME_OUT;
                break;
        case 5:         /* Command terminated; Bus reset by external device */
                hosterr = DID_RESET;
                break;
        case 6:         /* Unexpected Command Received w/ host as target */
                hosterr = DID_BAD_TARGET;
                break;
        case 80:                /* Unexpected Reselection */
        case 81:                /* Unexpected Selection */
                hosterr = DID_BAD_INTR;
                break;
        case 82:                /* Abort Command Message  */
                hosterr = DID_ABORT;
                break;
        case 83:                /* SCSI Bus Software Reset */
        case 84:                /* SCSI Bus Hardware Reset */
                hosterr = DID_RESET;
                break;
        default:                /* Reserved */
                hosterr = DID_ERROR;
        }
#ifdef WD7000_DEBUG
        if (scsierr || hosterr)
                dprintk("\nSCSI command error: SCSI 0x%02x host 0x%04x return %d\n", scsierr, in_error, hosterr);
#endif
        return (scsierr | (hosterr << 16));
}

#define wd7000_intr_ack(host)   outb (0, host->iobase + ASC_INTR_ACK)

static irqreturn_t wd7000_intr(int irq, void *dev_id)
{
        Adapter *host = (Adapter *) dev_id;
        int flag, icmb, errstatus, icmb_status;
        int host_error, scsi_error;
        Scb *scb;       /* for SCSI commands */
        IcbAny *icb;    /* for host commands */
        struct scsi_cmnd *SCpnt;
        Mailbox *icmbs = host->mb.icmb;
        unsigned long flags;

        spin_lock_irqsave(host->sh->host_lock, flags);
        host->int_counter++;

        dprintk("wd7000_intr: irq = %d, host = 0x%06lx\n", irq, (long) host);

        flag = inb(host->iobase + ASC_INTR_STAT);

        dprintk("wd7000_intr: intr stat = 0x%02x\n", flag);

        if (!(inb(host->iobase + ASC_STAT) & INT_IM)) {
                /* NB: these are _very_ possible if IRQ 15 is being used, since
                 * it's the "garbage collector" on the 2nd 8259 PIC.  Specifically,
                 * any interrupt signal into the 8259 which can't be identified
                 * comes out as 7 from the 8259, which is 15 to the host.  Thus, it
                 * is a good thing the WD7000 has an interrupt status port, so we
                 * can sort these out.  Otherwise, electrical noise and other such
                 * problems would be indistinguishable from valid interrupts...
                 */
                dprintk("wd7000_intr: phantom interrupt...\n");
                goto ack;
        }

        if (!(flag & MB_INTR))
                goto ack;

        /* The interrupt is for a mailbox */
        if (!(flag & IMB_INTR)) {
                dprintk("wd7000_intr: free outgoing mailbox\n");
                /*
                 * If sleep_on() and the "interrupt on free OGMB" command are
                 * used in mail_out(), wake_up() should correspondingly be called
                 * here.  For now, we don't need to do anything special.
                 */
                goto ack;
        }

        /* The interrupt is for an incoming mailbox */
        icmb = flag & MB_MASK;
        icmb_status = icmbs[icmb].status;
        if (icmb_status & 0x80) {       /* unsolicited - result in ICMB */
                dprintk("wd7000_intr: unsolicited interrupt 0x%02x\n", icmb_status);
                goto ack;
        }

        /* Aaaargh! (Zaga) */
        scb = isa_bus_to_virt(scsi2int((unchar *) icmbs[icmb].scbptr));
        icmbs[icmb].status = 0;
        if (scb->op & ICB_OP_MASK) {    /* an SCB is done */
                icb = (IcbAny *) scb;
                icb->status = icmb_status;
                icb->phase = 0;
                goto ack;
        }

        SCpnt = scb->SCpnt;
        if (--(SCpnt->SCp.phase) <= 0) {        /* all scbs are done */
                host_error = scb->vue | (icmb_status << 8);
                scsi_error = scb->status;
                errstatus = make_code(host_error, scsi_error);
                SCpnt->result = errstatus;

                free_scb(scb);

                SCpnt->scsi_done(SCpnt);
        }

 ack:
        dprintk("wd7000_intr: return from interrupt handler\n");
        wd7000_intr_ack(host);

        spin_unlock_irqrestore(host->sh->host_lock, flags);
        return IRQ_HANDLED;
}

static int wd7000_queuecommand(struct scsi_cmnd *SCpnt,
                void (*done)(struct scsi_cmnd *))
{
        Scb *scb;
        Sgb *sgb;
        unchar *cdb = (unchar *) SCpnt->cmnd;
        unchar idlun;
        short cdblen;
        int nseg;
        Adapter *host = (Adapter *) SCpnt->device->host->hostdata;

        cdblen = SCpnt->cmd_len;
        idlun = ((SCpnt->device->id << 5) & 0xe0) | (SCpnt->device->lun & 7);
        SCpnt->scsi_done = done;
        SCpnt->SCp.phase = 1;
        scb = alloc_scbs(SCpnt->device->host, 1);
        scb->idlun = idlun;
        memcpy(scb->cdb, cdb, cdblen);
        scb->direc = 0x40;      /* Disable direction check */

        scb->SCpnt = SCpnt;     /* so we can find stuff later */
        SCpnt->host_scribble = (unchar *) scb;
        scb->host = host;

        nseg = scsi_sg_count(SCpnt);
        if (nseg > 1) {
                struct scatterlist *sg;
                unsigned i;

                dprintk("Using scatter/gather with %d elements.\n", nseg);

                sgb = scb->sgb;
                scb->op = 1;
                any2scsi(scb->dataptr, (int) sgb);
                any2scsi(scb->maxlen, nseg * sizeof(Sgb));

                scsi_for_each_sg(SCpnt, sg, nseg, i) {
                        any2scsi(sgb[i].ptr, isa_page_to_bus(sg_page(sg)) + sg->offset);
                        any2scsi(sgb[i].len, sg->length);
                }
        } else {
                scb->op = 0;
                if (nseg) {
                        struct scatterlist *sg = scsi_sglist(SCpnt);
                        any2scsi(scb->dataptr, isa_page_to_bus(sg_page(sg)) + sg->offset);
                }
                any2scsi(scb->maxlen, scsi_bufflen(SCpnt));
        }

        /* FIXME: drop lock and yield here ? */

        while (!mail_out(host, scb))
                cpu_relax();    /* keep trying */

        return 0;
}

static int wd7000_diagnostics(Adapter * host, int code)
{
        static IcbDiag icb = { ICB_OP_DIAGNOSTICS };
        static unchar buf[256];
        unsigned long timeout;

        icb.type = code;
        any2scsi(icb.len, sizeof(buf));
        any2scsi(icb.ptr, (int) &buf);
        icb.phase = 1;
        /*
         * This routine is only called at init, so there should be OGMBs
         * available.  I'm assuming so here.  If this is going to
         * fail, I can just let the timeout catch the failure.
         */
        mail_out(host, (struct scb *) &icb);
        timeout = jiffies + WAITnexttimeout;    /* wait up to 2 seconds */
        while (icb.phase && time_before(jiffies, timeout)) {
                cpu_relax();    /* wait for completion */
                barrier();
        }

        if (icb.phase) {
                printk("wd7000_diagnostics: timed out.\n");
                return (0);
        }
        if (make_code(icb.vue | (icb.status << 8), 0)) {
                printk("wd7000_diagnostics: failed (0x%02x,0x%02x)\n", icb.vue, icb.status);
                return (0);
        }

        return (1);
}


static int wd7000_adapter_reset(Adapter * host)
{
        InitCmd init_cmd = {
                INITIALIZATION,
                7,
                host->bus_on,
                host->bus_off,
                0,
                {0, 0, 0},
                OGMB_CNT,
                ICMB_CNT
        };
        int diag;
        /*
         *  Reset the adapter - only.  The SCSI bus was initialized at power-up,
         *  and we need to do this just so we control the mailboxes, etc.
         */
        outb(ASC_RES, host->iobase + ASC_CONTROL);
        udelay(40);             /* reset pulse: this is 40us, only need 25us */
        outb(0, host->iobase + ASC_CONTROL);
        host->control = 0;      /* this must always shadow ASC_CONTROL */

        if (WAIT(host->iobase + ASC_STAT, ASC_STATMASK, CMD_RDY, 0)) {
                printk(KERN_ERR "wd7000_init: WAIT timed out.\n");
                return -1;      /* -1 = not ok */
        }

        if ((diag = inb(host->iobase + ASC_INTR_STAT)) != 1) {
                printk("wd7000_init: ");

                switch (diag) {
                case 2:
                        printk(KERN_ERR "RAM failure.\n");
                        break;
                case 3:
                        printk(KERN_ERR "FIFO R/W failed\n");
                        break;
                case 4:
                        printk(KERN_ERR "SBIC register R/W failed\n");
                        break;
                case 5:
                        printk(KERN_ERR "Initialization D-FF failed.\n");
                        break;
                case 6:
                        printk(KERN_ERR "Host IRQ D-FF failed.\n");
                        break;
                case 7:
                        printk(KERN_ERR "ROM checksum error.\n");
                        break;
                default:
                        printk(KERN_ERR "diagnostic code 0x%02Xh received.\n", diag);
                }
                return -1;
        }
        /* Clear mailboxes */
        memset(&(host->mb), 0, sizeof(host->mb));

        /* Execute init command */
        any2scsi((unchar *) & (init_cmd.mailboxes), (int) &(host->mb));
        if (!command_out(host, (unchar *) & init_cmd, sizeof(init_cmd))) {
                printk(KERN_ERR "wd7000_adapter_reset: adapter initialization failed.\n");
                return -1;
        }

        if (WAIT(host->iobase + ASC_STAT, ASC_STATMASK, ASC_INIT, 0)) {
                printk("wd7000_adapter_reset: WAIT timed out.\n");
                return -1;
        }
        return 0;
}

static int wd7000_init(Adapter * host)
{
        if (wd7000_adapter_reset(host) == -1)
                return 0;


        if (request_irq(host->irq, wd7000_intr, IRQF_DISABLED, "wd7000", host)) {
                printk("wd7000_init: can't get IRQ %d.\n", host->irq);
                return (0);
        }
        if (request_dma(host->dma, "wd7000")) {
                printk("wd7000_init: can't get DMA channel %d.\n", host->dma);
                free_irq(host->irq, host);
                return (0);
        }
        wd7000_enable_dma(host);
        wd7000_enable_intr(host);

        if (!wd7000_diagnostics(host, ICB_DIAG_FULL)) {
                free_dma(host->dma);
                free_irq(host->irq, NULL);
                return (0);
        }

        return (1);
}


static void wd7000_revision(Adapter * host)
{
        static IcbRevLvl icb = { ICB_OP_GET_REVISION };

        icb.phase = 1;
        /*
         * Like diagnostics, this is only done at init time, in fact, from
         * wd7000_detect, so there should be OGMBs available.  If it fails,
         * the only damage will be that the revision will show up as 0.0,
         * which in turn means that scatter/gather will be disabled.
         */
        mail_out(host, (struct scb *) &icb);
        while (icb.phase) {
                cpu_relax();    /* wait for completion */
                barrier();
        }
        host->rev1 = icb.primary;
        host->rev2 = icb.secondary;
}


#undef SPRINTF
#define SPRINTF(args...) { if (pos < (buffer + length)) pos += sprintf (pos, ## args); }

static int wd7000_set_info(char *buffer, int length, struct Scsi_Host *host)
{
        dprintk("Buffer = <%.*s>, length = %d\n", length, buffer, length);

        /*
         * Currently this is a no-op
         */
        dprintk("Sorry, this function is currently out of order...\n");
        return (length);
}


static int wd7000_proc_info(struct Scsi_Host *host, char *buffer, char **start, off_t offset, int length,  int inout)
{
        Adapter *adapter = (Adapter *)host->hostdata;
        unsigned long flags;
        char *pos = buffer;
#ifdef WD7000_DEBUG
        Mailbox *ogmbs, *icmbs;
        short count;
#endif

        /*
         * Has data been written to the file ?
         */
        if (inout)
                return (wd7000_set_info(buffer, length, host));

        spin_lock_irqsave(host->host_lock, flags);
        SPRINTF("Host scsi%d: Western Digital WD-7000 (rev %d.%d)\n", host->host_no, adapter->rev1, adapter->rev2);
        SPRINTF("  IO base:      0x%x\n", adapter->iobase);
        SPRINTF("  IRQ:          %d\n", adapter->irq);
        SPRINTF("  DMA channel:  %d\n", adapter->dma);
        SPRINTF("  Interrupts:   %d\n", adapter->int_counter);
        SPRINTF("  BUS_ON time:  %d nanoseconds\n", adapter->bus_on * 125);
        SPRINTF("  BUS_OFF time: %d nanoseconds\n", adapter->bus_off * 125);

#ifdef WD7000_DEBUG
        ogmbs = adapter->mb.ogmb;
        icmbs = adapter->mb.icmb;

        SPRINTF("\nControl port value: 0x%x\n", adapter->control);
        SPRINTF("Incoming mailbox:\n");
        SPRINTF("  size: %d\n", ICMB_CNT);
        SPRINTF("  queued messages: ");

        for (i = count = 0; i < ICMB_CNT; i++)
                if (icmbs[i].status) {
                        count++;
                        SPRINTF("0x%x ", i);
                }

        SPRINTF(count ? "\n" : "none\n");

        SPRINTF("Outgoing mailbox:\n");
        SPRINTF("  size: %d\n", OGMB_CNT);
        SPRINTF("  next message: 0x%x\n", adapter->next_ogmb);
        SPRINTF("  queued messages: ");

        for (i = count = 0; i < OGMB_CNT; i++)
                if (ogmbs[i].status) {
                        count++;
                        SPRINTF("0x%x ", i);
                }

        SPRINTF(count ? "\n" : "none\n");
#endif

        spin_unlock_irqrestore(host->host_lock, flags);

        /*
         * Calculate start of next buffer, and return value.
         */
        *start = buffer + offset;

        if ((pos - buffer) < offset)
                return (0);
        else if ((pos - buffer - offset) < length)
                return (pos - buffer - offset);
        else
                return (length);
}


/*
 *  Returns the number of adapters this driver is supporting.
 *
 *  The source for hosts.c says to wait to call scsi_register until 100%
 *  sure about an adapter.  We need to do it a little sooner here; we
 *  need the storage set up by scsi_register before wd7000_init, and
 *  changing the location of an Adapter structure is more trouble than
 *  calling scsi_unregister.
 *
 */

static __init int wd7000_detect(struct scsi_host_template *tpnt)
{
        short present = 0, biosaddr_ptr, sig_ptr, i, pass;
        short biosptr[NUM_CONFIGS];
        unsigned iobase;
        Adapter *host = NULL;
        struct Scsi_Host *sh;
        int unit = 0;

        dprintk("wd7000_detect: started\n");

#ifdef MODULE
        if (wd7000)
                wd7000_setup(wd7000);
#endif

        for (i = 0; i < UNITS; wd7000_host[i++] = NULL);
        for (i = 0; i < NUM_CONFIGS; biosptr[i++] = -1);

        tpnt->proc_name = "wd7000";
        tpnt->proc_info = &wd7000_proc_info;

        /*
         * Set up SCB free list, which is shared by all adapters
         */
        init_scbs();

        for (pass = 0; pass < NUM_CONFIGS; pass++) {
                /*
                 * First, search for BIOS SIGNATURE...
                 */
                for (biosaddr_ptr = 0; biosaddr_ptr < NUM_ADDRS; biosaddr_ptr++)
                        for (sig_ptr = 0; sig_ptr < NUM_SIGNATURES; sig_ptr++) {
                                for (i = 0; i < pass; i++)
                                        if (biosptr[i] == biosaddr_ptr)
                                                break;

                                if (i == pass) {
                                        void __iomem *biosaddr = ioremap(wd7000_biosaddr[biosaddr_ptr] + signatures[sig_ptr].ofs,
                                                                 signatures[sig_ptr].len);
                                        short bios_match = 1;

                                        if (biosaddr)
                                                bios_match = check_signature(biosaddr, signatures[sig_ptr].sig, signatures[sig_ptr].len);

                                        iounmap(biosaddr);

                                        if (bios_match)
                                                goto bios_matched;
                                }
                        }

              bios_matched:
                /*
                 * BIOS SIGNATURE has been found.
                 */
#ifdef WD7000_DEBUG
                dprintk("wd7000_detect: pass %d\n", pass + 1);

                if (biosaddr_ptr == NUM_ADDRS)
                        dprintk("WD-7000 SST BIOS not detected...\n");
                else
                        dprintk("WD-7000 SST BIOS detected at 0x%lx: checking...\n", wd7000_biosaddr[biosaddr_ptr]);
#endif

                if (configs[pass].irq < 0)
                        continue;

                if (unit == UNITS)
                        continue;

                iobase = configs[pass].iobase;

                dprintk("wd7000_detect: check IO 0x%x region...\n", iobase);

                if (request_region(iobase, 4, "wd7000")) {

                        dprintk("wd7000_detect: ASC reset (IO 0x%x) ...", iobase);
                        /*
                         * ASC reset...
                         */
                        outb(ASC_RES, iobase + ASC_CONTROL);
                        msleep(10);
                        outb(0, iobase + ASC_CONTROL);

                        if (WAIT(iobase + ASC_STAT, ASC_STATMASK, CMD_RDY, 0)) {
                                dprintk("failed!\n");
                                goto err_release;
                        } else
                                dprintk("ok!\n");

                        if (inb(iobase + ASC_INTR_STAT) == 1) {
                                /*
                                 *  We register here, to get a pointer to the extra space,
                                 *  which we'll use as the Adapter structure (host) for
                                 *  this adapter.  It is located just after the registered
                                 *  Scsi_Host structure (sh), and is located by the empty
                                 *  array hostdata.
                                 */
                                sh = scsi_register(tpnt, sizeof(Adapter));
                                if (sh == NULL)
                                        goto err_release;

                                host = (Adapter *) sh->hostdata;

                                dprintk("wd7000_detect: adapter allocated at 0x%x\n", (int) host);
                                memset(host, 0, sizeof(Adapter));

                                host->irq = configs[pass].irq;
                                host->dma = configs[pass].dma;
                                host->iobase = iobase;
                                host->int_counter = 0;
                                host->bus_on = configs[pass].bus_on;
                                host->bus_off = configs[pass].bus_off;
                                host->sh = wd7000_host[unit] = sh;
                                unit++;

                                dprintk("wd7000_detect: Trying init WD-7000 card at IO " "0x%x, IRQ %d, DMA %d...\n", host->iobase, host->irq, host->dma);

                                if (!wd7000_init(host)) /* Initialization failed */
                                        goto err_unregister;

                                /*
                                 *  OK from here - we'll use this adapter/configuration.
                                 */
                                wd7000_revision(host);  /* important for scatter/gather */

                                /*
                                 *  For boards before rev 6.0, scatter/gather isn't supported.
                                 */
                                if (host->rev1 < 6)
                                        sh->sg_tablesize = 1;

                                present++;      /* count it */

                                if (biosaddr_ptr != NUM_ADDRS)
                                        biosptr[pass] = biosaddr_ptr;

                                printk(KERN_INFO "Western Digital WD-7000 (rev %d.%d) ", host->rev1, host->rev2);
                                printk("using IO 0x%x, IRQ %d, DMA %d.\n", host->iobase, host->irq, host->dma);
                                printk("  BUS_ON time: %dns, BUS_OFF time: %dns\n", host->bus_on * 125, host->bus_off * 125);
                        }
                } else
                        dprintk("wd7000_detect: IO 0x%x region already allocated!\n", iobase);

                continue;

              err_unregister:
                scsi_unregister(sh);
              err_release:
                release_region(iobase, 4);

        }

        if (!present)
                printk("Failed initialization of WD-7000 SCSI card!\n");

        return (present);
}

static int wd7000_release(struct Scsi_Host *shost)
{
        if (shost->irq)
                free_irq(shost->irq, NULL);
        if (shost->io_port && shost->n_io_port)
                release_region(shost->io_port, shost->n_io_port);
        scsi_unregister(shost);
        return 0;
}

#if 0
/*
 *  I have absolutely NO idea how to do an abort with the WD7000...
 */
static int wd7000_abort(Scsi_Cmnd * SCpnt)
{
        Adapter *host = (Adapter *) SCpnt->device->host->hostdata;

        if (inb(host->iobase + ASC_STAT) & INT_IM) {
                printk("wd7000_abort: lost interrupt\n");
                wd7000_intr_handle(host->irq, NULL, NULL);
                return FAILED;
        }
        return FAILED;
}
#endif

/*
 *  Last resort. Reinitialize the board.
 */

static int wd7000_host_reset(struct scsi_cmnd *SCpnt)
{
        Adapter *host = (Adapter *) SCpnt->device->host->hostdata;

        spin_unlock_irq(SCpnt->device->host->host_lock);

        if (wd7000_adapter_reset(host) < 0) {
                spin_unlock_irq(SCpnt->device->host->host_lock);
                return FAILED;
        }

        wd7000_enable_intr(host);

        spin_unlock_irq(SCpnt->device->host->host_lock);
        return SUCCESS;
}

/*
 *  This was borrowed directly from aha1542.c. (Zaga)
 */

static int wd7000_biosparam(struct scsi_device *sdev,
                struct block_device *bdev, sector_t capacity, int *ip)
{
        char b[BDEVNAME_SIZE];

        dprintk("wd7000_biosparam: dev=%s, size=%d, ",
                bdevname(bdev, b), capacity);
        (void)b;        /* unused var warning? */

        /*
         * try default translation
         */
        ip[0] = 64;
        ip[1] = 32;
        ip[2] = capacity >> 11;

        /*
         * for disks >1GB do some guessing
         */
        if (ip[2] >= 1024) {
                int info[3];

                /*
                 * try to figure out the geometry from the partition table
                 */
                if ((scsicam_bios_param(bdev, capacity, info) < 0) || !(((info[0] == 64) && (info[1] == 32)) || ((info[0] == 255) && (info[1] == 63)))) {
                        printk("wd7000_biosparam: unable to verify geometry for disk with >1GB.\n" "                  using extended translation.\n");

                        ip[0] = 255;
                        ip[1] = 63;
                        ip[2] = (unsigned long) capacity / (255 * 63);
                } else {
                        ip[0] = info[0];
                        ip[1] = info[1];
                        ip[2] = info[2];

                        if (info[0] == 255)
                                printk(KERN_INFO "%s: current partition table is " "using extended translation.\n", __func__);
                }
        }

        dprintk("bios geometry: head=%d, sec=%d, cyl=%d\n", ip[0], ip[1], ip[2]);
        dprintk("WARNING: check, if the bios geometry is correct.\n");

        return (0);
}

MODULE_AUTHOR("Thomas Wuensche, John Boyd, Miroslav Zagorac");
MODULE_DESCRIPTION("Driver for the WD7000 series ISA controllers");
MODULE_LICENSE("GPL");

static struct scsi_host_template driver_template = {
        .proc_name              = "wd7000",
        .proc_info              = wd7000_proc_info,
        .name                   = "Western Digital WD-7000",
        .detect                 = wd7000_detect,
        .release                = wd7000_release,
        .queuecommand           = wd7000_queuecommand,
        .eh_host_reset_handler  = wd7000_host_reset,
        .bios_param             = wd7000_biosparam,
        .can_queue              = WD7000_Q,
        .this_id                = 7,
        .sg_tablesize           = WD7000_SG,
        .cmd_per_lun            = 1,
        .unchecked_isa_dma      = 1,
        .use_clustering         = ENABLE_CLUSTERING,
};

#include "scsi_module.c"