Import 2.1.118

[davej-history.git] / drivers / block / ataflop.c

/*
 *  drivers/block/ataflop.c
 *
 *  Copyright (C) 1993  Greg Harp
 *  Atari Support by Bjoern Brauel, Roman Hodek
 *
 *  Big cleanup Sep 11..14 1994 Roman Hodek:
 *   - Driver now works interrupt driven
 *   - Support for two drives; should work, but I cannot test that :-(
 *   - Reading is done in whole tracks and buffered to speed up things
 *   - Disk change detection and drive deselecting after motor-off
 *     similar to TOS
 *   - Autodetection of disk format (DD/HD); untested yet, because I
 *     don't have an HD drive :-(
 *
 *  Fixes Nov 13 1994 Martin Schaller:
 *   - Autodetection works now
 *   - Support for 5 1/4'' disks
 *   - Removed drive type (unknown on atari)
 *   - Do seeks with 8 Mhz
 *
 *  Changes by Andreas Schwab:
 *   - After errors in multiple read mode try again reading single sectors
 *  (Feb 1995):
 *   - Clean up error handling
 *   - Set blk_size for proper size checking
 *   - Initialize track register when testing presence of floppy
 *   - Implement some ioctl's
 *
 *  Changes by Torsten Lang:
 *   - When probing the floppies we should add the FDCCMDADD_H flag since
 *     the FDC will otherwise wait forever when no disk is inserted...
 *
 * ++ Freddi Aschwanden (fa) 20.9.95 fixes for medusa:
 *  - MFPDELAY() after each FDC access -> atari 
 *  - more/other disk formats
 *  - DMA to the block buffer directly if we have a 32bit DMA
 *  - for medusa, the step rate is always 3ms
 *  - on medusa, use only cache_push()
 * Roman:
 *  - Make disk format numbering independent from minors
 *  - Let user set max. supported drive type (speeds up format
 *    detection, saves buffer space)
 *
 * Roman 10/15/95:
 *  - implement some more ioctls
 *  - disk formatting
 *  
 * Andreas 95/12/12:
 *  - increase gap size at start of track for HD/ED disks
 *
 * Michael (MSch) 11/07/96:
 *  - implemented FDSETPRM and FDDEFPRM ioctl
 *
 * Andreas (97/03/19):
 *  - implemented missing BLK* ioctls
 *
 *  Things left to do:
 *   - Formatting
 *   - Maybe a better strategy for disk change detection (does anyone
 *     know one?)
 */

#include <linux/module.h>

#include <linux/sched.h>
#include <linux/string.h>
#include <linux/fs.h>
#include <linux/fcntl.h>
#include <linux/kernel.h>
#include <linux/timer.h>
#include <linux/fd.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/delay.h>
#include <linux/mm.h>
#include <linux/malloc.h>
#include <linux/init.h>

#include <asm/setup.h>
#include <asm/system.h>
#include <asm/bitops.h>
#include <asm/irq.h>
#include <asm/pgtable.h>
#include <asm/uaccess.h>

#include <asm/atafd.h>
#include <asm/atafdreg.h>
#include <asm/atarihw.h>
#include <asm/atariints.h>
#include <asm/atari_stdma.h>
#include <asm/atari_stram.h>

#define MAJOR_NR FLOPPY_MAJOR
#include <linux/blk.h>

#define FD_MAX_UNITS 2

#undef DEBUG

/* Disk types: DD, HD, ED */
static struct atari_disk_type {
        const char      *name;
        unsigned        spt;            /* sectors per track */
        unsigned        blocks;         /* total number of blocks */
        unsigned        fdc_speed;      /* fdc_speed setting */
        unsigned        stretch;        /* track doubling ? */
} disk_type[] = {
        { "d360",  9, 720, 0, 0},       /*  0: 360kB diskette */
        { "D360",  9, 720, 0, 1},       /*  1: 360kb in 720k or 1.2MB drive */
        { "D720",  9,1440, 0, 0},       /*  2: 720kb in 720k or 1.2MB drive */
        { "D820", 10,1640, 0, 0},       /*  3: DD disk with 82 tracks/10 sectors */
/* formats above are probed for type DD */
#define MAX_TYPE_DD 3
        { "h1200",15,2400, 3, 0},       /*  4: 1.2MB diskette */
        { "H1440",18,2880, 3, 0},       /*  5: 1.4 MB diskette (HD) */
        { "H1640",20,3280, 3, 0},       /*  6: 1.64MB diskette (fat HD) 82 tr 20 sec */
/* formats above are probed for types DD and HD */
#define MAX_TYPE_HD 6
        { "E2880",36,5760, 3, 0},       /*  7: 2.8 MB diskette (ED) */
        { "E3280",40,6560, 3, 0},       /*  8: 3.2 MB diskette (fat ED) 82 tr 40 sec */
/* formats above are probed for types DD, HD and ED */
#define MAX_TYPE_ED 8
/* types below are never autoprobed */
        { "H1680",21,3360, 3, 0},       /*  9: 1.68MB diskette (fat HD) 80 tr 21 sec */
        { "h410",10,820, 0, 1},         /* 10: 410k diskette 41 tr 10 sec, stretch */
        { "h1476",18,2952, 3, 0},       /* 11: 1.48MB diskette 82 tr 18 sec */
        { "H1722",21,3444, 3, 0},       /* 12: 1.72MB diskette 82 tr 21 sec */
        { "h420",10,840, 0, 1},         /* 13: 420k diskette 42 tr 10 sec, stretch */
        { "H830",10,1660, 0, 0},        /* 14: 820k diskette 83 tr 10 sec */
        { "h1494",18,2952, 3, 0},       /* 15: 1.49MB diskette 83 tr 18 sec */
        { "H1743",21,3486, 3, 0},       /* 16: 1.74MB diskette 83 tr 21 sec */
        { "h880",11,1760, 0, 0},        /* 17: 880k diskette 80 tr 11 sec */
        { "D1040",13,2080, 0, 0},       /* 18: 1.04MB diskette 80 tr 13 sec */
        { "D1120",14,2240, 0, 0},       /* 19: 1.12MB diskette 80 tr 14 sec */
        { "h1600",20,3200, 3, 0},       /* 20: 1.60MB diskette 80 tr 20 sec */
        { "H1760",22,3520, 3, 0},       /* 21: 1.76MB diskette 80 tr 22 sec */
        { "H1920",24,3840, 3, 0},       /* 22: 1.92MB diskette 80 tr 24 sec */
        { "E3200",40,6400, 3, 0},       /* 23: 3.2MB diskette 80 tr 40 sec */
        { "E3520",44,7040, 3, 0},       /* 24: 3.52MB diskette 80 tr 44 sec */
        { "E3840",48,7680, 3, 0},       /* 25: 3.84MB diskette 80 tr 48 sec */
        { "H1840",23,3680, 3, 0},       /* 26: 1.84MB diskette 80 tr 23 sec */
        { "D800",10,1600, 0, 0},        /* 27: 800k diskette 80 tr 10 sec */
};

static int StartDiskType[] = {
        MAX_TYPE_DD,
        MAX_TYPE_HD,
        MAX_TYPE_ED
};

#define TYPE_DD         0
#define TYPE_HD         1
#define TYPE_ED         2

static int DriveType = TYPE_HD;

/* Array for translating minors into disk formats */
static struct {
        int      index;
        unsigned drive_types;
} minor2disktype[] = {
        {  0, TYPE_DD },        /*  1: d360 */
        {  4, TYPE_HD },        /*  2: h1200 */
        {  1, TYPE_DD },        /*  3: D360 */
        {  2, TYPE_DD },        /*  4: D720 */
        {  1, TYPE_DD },        /*  5: h360 = D360 */
        {  2, TYPE_DD },        /*  6: h720 = D720 */
        {  5, TYPE_HD },        /*  7: H1440 */
        {  7, TYPE_ED },        /*  8: E2880 */
/* some PC formats :-) */
        {  8, TYPE_ED },        /*  9: E3280    <- was "CompaQ" == E2880 for PC */
        {  5, TYPE_HD },        /* 10: h1440 = H1440 */
        {  9, TYPE_HD },        /* 11: H1680 */
        { 10, TYPE_DD },        /* 12: h410  */
        {  3, TYPE_DD },        /* 13: H820     <- == D820, 82x10 */
        { 11, TYPE_HD },        /* 14: h1476 */
        { 12, TYPE_HD },        /* 15: H1722 */
        { 13, TYPE_DD },        /* 16: h420  */
        { 14, TYPE_DD },        /* 17: H830  */
        { 15, TYPE_HD },        /* 18: h1494 */
        { 16, TYPE_HD },        /* 19: H1743 */
        { 17, TYPE_DD },        /* 20: h880  */
        { 18, TYPE_DD },        /* 21: D1040 */
        { 19, TYPE_DD },        /* 22: D1120 */
        { 20, TYPE_HD },        /* 23: h1600 */
        { 21, TYPE_HD },        /* 24: H1760 */
        { 22, TYPE_HD },        /* 25: H1920 */
        { 23, TYPE_ED },        /* 26: E3200 */
        { 24, TYPE_ED },        /* 27: E3520 */
        { 25, TYPE_ED },        /* 28: E3840 */
        { 26, TYPE_HD },        /* 29: H1840 */
        { 27, TYPE_DD },        /* 30: D800  */
        {  6, TYPE_HD },        /* 31: H1640    <- was H1600 == h1600 for PC */
};

#define NUM_DISK_MINORS (sizeof(minor2disktype)/sizeof(*minor2disktype))

/*
 * Maximum disk size (in kilobytes). This default is used whenever the
 * current disk size is unknown.
 */
#define MAX_DISK_SIZE 3280

/*
 * MSch: User-provided type information. 'drive' points to
 * the respective entry of this array. Set by FDSETPRM ioctls.
 */
static struct atari_disk_type user_params[FD_MAX_UNITS];

/*
 * User-provided permanent type information. 'drive' points to
 * the respective entry of this array.  Set by FDDEFPRM ioctls, 
 * restored upon disk change by floppy_revalidate() if valid (as seen by
 * default_params[].blocks > 0 - a bit in unit[].flags might be used for this?)
 */
static struct atari_disk_type default_params[FD_MAX_UNITS] = {
        { NULL,  0, 0, 0, 0},  };

static int floppy_sizes[256];
static int floppy_blocksizes[256] = { 0, };

/* current info on each unit */
static struct atari_floppy_struct {
        int connected;                          /* !=0 : drive is connected */
        int autoprobe;                          /* !=0 : do autoprobe       */

        struct atari_disk_type  *disktype;      /* current type of disk */

        int track;              /* current head position or -1 if
                                   unknown */
        unsigned int steprate;  /* steprate setting */
        unsigned int wpstat;    /* current state of WP signal (for
                                   disk change detection) */
        int flags;              /* flags */
} unit[FD_MAX_UNITS];

#define UD      unit[drive]
#define UDT     unit[drive].disktype
#define SUD     unit[SelectedDrive]
#define SUDT    unit[SelectedDrive].disktype


#define FDC_READ(reg) ({                        \
    /* unsigned long __flags; */                \
    unsigned short __val;                       \
    /* save_flags(__flags); cli(); */           \
    dma_wd.dma_mode_status = 0x80 | (reg);      \
    udelay(25);                                 \
    __val = dma_wd.fdc_acces_seccount;          \
    MFPDELAY();                                 \
    /* restore_flags(__flags); */               \
    __val & 0xff;                               \
})

#define FDC_WRITE(reg,val)                      \
    do {                                        \
        /* unsigned long __flags; */            \
        /* save_flags(__flags); cli(); */       \
        dma_wd.dma_mode_status = 0x80 | (reg);  \
        udelay(25);                             \
        dma_wd.fdc_acces_seccount = (val);      \
        MFPDELAY();                             \
        /* restore_flags(__flags); */           \
    } while(0)


/* Buffering variables:
 * First, there is a DMA buffer in ST-RAM that is used for floppy DMA
 * operations. Second, a track buffer is used to cache a whole track
 * of the disk to save read operations. These are two separate buffers
 * because that allows write operations without clearing the track buffer.
 */

static int MaxSectors[] = {
        11, 22, 44
};
static int BufferSize[] = {
        15*512, 30*512, 60*512
};

#define BUFFER_SIZE     (BufferSize[DriveType])

unsigned char *DMABuffer;                         /* buffer for writes */
static unsigned long PhysDMABuffer;   /* physical address */

static int UseTrackbuffer = -1;           /* Do track buffering? */
MODULE_PARM(UseTrackbuffer, "i");

unsigned char *TrackBuffer;                       /* buffer for reads */
static unsigned long PhysTrackBuffer; /* physical address */
static int BufferDrive, BufferSide, BufferTrack;
static int read_track;          /* non-zero if we are reading whole tracks */

#define SECTOR_BUFFER(sec)      (TrackBuffer + ((sec)-1)*512)
#define IS_BUFFERED(drive,side,track) \
    (BufferDrive == (drive) && BufferSide == (side) && BufferTrack == (track))

/*
 * These are global variables, as that's the easiest way to give
 * information to interrupts. They are the data used for the current
 * request.
 */
static int SelectedDrive = 0;
static int ReqCmd, ReqBlock;
static int ReqSide, ReqTrack, ReqSector, ReqCnt;
static int HeadSettleFlag = 0;
static unsigned char *ReqData, *ReqBuffer;
static int MotorOn = 0, MotorOffTrys;
static int IsFormatting = 0, FormatError;

static int UserSteprate[FD_MAX_UNITS] = { -1, -1 };
MODULE_PARM(UserSteprate, "1-" __MODULE_STRING(FD_MAX_UNITS) "i");

/* Synchronization of FDC access. */
static volatile int fdc_busy = 0;
static struct wait_queue *fdc_wait = NULL;
static struct wait_queue *format_wait = NULL;

static unsigned int changed_floppies = 0xff, fake_change = 0;
#define CHECK_CHANGE_DELAY      HZ/2

#define FD_MOTOR_OFF_DELAY      (3*HZ)
#define FD_MOTOR_OFF_MAXTRY     (10*20)

#define FLOPPY_TIMEOUT          (6*HZ)
#define RECALIBRATE_ERRORS      4       /* After this many errors the drive
                                         * will be recalibrated. */
#define MAX_ERRORS              8       /* After this many errors the driver
                                         * will give up. */


#define START_MOTOR_OFF_TIMER(delay)                            \
    do {                                                        \
        motor_off_timer.expires = jiffies + (delay);            \
        add_timer( &motor_off_timer );                          \
        MotorOffTrys = 0;                                       \
        } while(0)

#define START_CHECK_CHANGE_TIMER(delay)                         \
    do {                                                        \
        timer_table[FLOPPY_TIMER].expires = jiffies + (delay);  \
        timer_active |= (1 << FLOPPY_TIMER);                    \
        } while(0)

#define START_TIMEOUT()                                         \
    mod_timer(&timeout_timer, jiffies + FLOPPY_TIMEOUT)

#define STOP_TIMEOUT()                                          \
    del_timer(&timeout_timer)


/*
 * The driver is trying to determine the correct media format
 * while Probing is set. fd_rwsec_done() clears it after a
 * successful access.
 */
static int Probing = 0;

/* This flag is set when a dummy seek is necessary to make the WP
 * status bit accessible.
 */
static int NeedSeek = 0;


#ifdef DEBUG
#define DPRINT(a)       printk a
#else
#define DPRINT(a)
#endif

/***************************** Prototypes *****************************/

static void fd_select_side( int side );
static void fd_select_drive( int drive );
static void fd_deselect( void );
static void fd_motor_off_timer( unsigned long dummy );
static void check_change( void );
static __inline__ void set_head_settle_flag( void );
static __inline__ int get_head_settle_flag( void );
static void floppy_irq (int irq, void *dummy, struct pt_regs *fp);
static void fd_error( void );
static int do_format(kdev_t drive, struct atari_format_descr *desc);
static void do_fd_action( int drive );
static void fd_calibrate( void );
static void fd_calibrate_done( int status );
static void fd_seek( void );
static void fd_seek_done( int status );
static void fd_rwsec( void );
static void fd_readtrack_check( unsigned long dummy );
static void fd_rwsec_done( int status );
static void fd_rwsec_done1(int status);
static void fd_writetrack( void );
static void fd_writetrack_done( int status );
static void fd_times_out( unsigned long dummy );
static void finish_fdc( void );
static void finish_fdc_done( int dummy );
static void floppy_off( unsigned int nr);
static __inline__ void copy_buffer( void *from, void *to);
static void setup_req_params( int drive );
static void redo_fd_request( void);
static int invalidate_drive(kdev_t rdev);
static int fd_ioctl( struct inode *inode, struct file *filp, unsigned int
                     cmd, unsigned long param);
static void fd_probe( int drive );
static int fd_test_drive_present( int drive );
static void config_types( void );
static int floppy_open( struct inode *inode, struct file *filp );
static int floppy_release( struct inode * inode, struct file * filp );

/************************* End of Prototypes **************************/

static struct timer_list motor_off_timer =
        { NULL, NULL, 0, 0, fd_motor_off_timer };
static struct timer_list readtrack_timer =
        { NULL, NULL, 0, 0, fd_readtrack_check };

static struct timer_list timeout_timer =
        { NULL, NULL, 0, 0, fd_times_out };



/* Select the side to use. */

static void fd_select_side( int side )
{
        unsigned long flags;

        save_flags(flags);
        cli(); /* protect against various other ints mucking around with the PSG */
  
        sound_ym.rd_data_reg_sel = 14; /* Select PSG Port A */
        sound_ym.wd_data = (side == 0) ? sound_ym.rd_data_reg_sel | 0x01 :
                                         sound_ym.rd_data_reg_sel & 0xfe;

        restore_flags(flags);
}


/* Select a drive, update the FDC's track register and set the correct
 * clock speed for this disk's type.
 */

static void fd_select_drive( int drive )
{
        unsigned long flags;
        unsigned char tmp;
  
        if (drive == SelectedDrive)
          return;

        save_flags(flags);
        cli(); /* protect against various other ints mucking around with the PSG */
        sound_ym.rd_data_reg_sel = 14; /* Select PSG Port A */
        tmp = sound_ym.rd_data_reg_sel;
        sound_ym.wd_data = (tmp | DSKDRVNONE) & ~(drive == 0 ? DSKDRV0 : DSKDRV1);
        atari_dont_touch_floppy_select = 1;
        restore_flags(flags);

        /* restore track register to saved value */
        FDC_WRITE( FDCREG_TRACK, UD.track );
        udelay(25);

        /* select 8/16 MHz */
        if (UDT)
                if (ATARIHW_PRESENT(FDCSPEED))
                        dma_wd.fdc_speed = UDT->fdc_speed;
        
        SelectedDrive = drive;
}


/* Deselect both drives. */

static void fd_deselect( void )
{
        unsigned long flags;

        save_flags(flags);
        cli(); /* protect against various other ints mucking around with the PSG */
        atari_dont_touch_floppy_select = 0;
        sound_ym.rd_data_reg_sel=14;    /* Select PSG Port A */
        sound_ym.wd_data = (sound_ym.rd_data_reg_sel |
                            (MACH_IS_FALCON ? 3 : 7)); /* no drives selected */
        /* On Falcon, the drive B select line is used on the printer port, so
         * leave it alone... */
        SelectedDrive = -1;
        restore_flags(flags);
}


/* This timer function deselects the drives when the FDC switched the
 * motor off. The deselection cannot happen earlier because the FDC
 * counts the index signals, which arrive only if one drive is selected.
 */

static void fd_motor_off_timer( unsigned long dummy )
{
/*      unsigned long flags; */
        unsigned char status;
        int                   delay;

        del_timer( &motor_off_timer );
        
        if (SelectedDrive < 0)
                /* no drive selected, needn't deselect anyone */
                return;

/*      save_flags(flags);
        cli(); */
        
        if (stdma_islocked())
                goto retry;

        status = FDC_READ( FDCREG_STATUS );

        if (!(status & 0x80)) {
                /* motor already turned off by FDC -> deselect drives */
                MotorOn = 0;
                fd_deselect();
/*              restore_flags(flags); */
                return;
        }
        /* not yet off, try again */

  retry:
/*      restore_flags(flags); */
        /* Test again later; if tested too often, it seems there is no disk
         * in the drive and the FDC will leave the motor on forever (or,
         * at least until a disk is inserted). So we'll test only twice
         * per second from then on...
         */
        delay = (MotorOffTrys < FD_MOTOR_OFF_MAXTRY) ?
                        (++MotorOffTrys, HZ/20) : HZ/2;
        START_MOTOR_OFF_TIMER( delay );
}


/* This function is repeatedly called to detect disk changes (as good
 * as possible) and keep track of the current state of the write protection.
 */

static void check_change( void )
{
        static int    drive = 0;

        unsigned long flags;
        unsigned char old_porta;
        int                       stat;

        if (++drive > 1 || !UD.connected)
                drive = 0;

        save_flags(flags);
        cli(); /* protect against various other ints mucking around with the PSG */

        if (!stdma_islocked()) {
                sound_ym.rd_data_reg_sel = 14;
                old_porta = sound_ym.rd_data_reg_sel;
                sound_ym.wd_data = (old_porta | DSKDRVNONE) &
                                       ~(drive == 0 ? DSKDRV0 : DSKDRV1);
                stat = !!(FDC_READ( FDCREG_STATUS ) & FDCSTAT_WPROT);
                sound_ym.wd_data = old_porta;

                if (stat != UD.wpstat) {
                        DPRINT(( "wpstat[%d] = %d\n", drive, stat ));
                        UD.wpstat = stat;
                        set_bit (drive, &changed_floppies);
                }
        }
        restore_flags(flags);

        START_CHECK_CHANGE_TIMER( CHECK_CHANGE_DELAY );
}

 
/* Handling of the Head Settling Flag: This flag should be set after each
 * seek operation, because we don't use seeks with verify.
 */

static __inline__ void set_head_settle_flag( void )
{
        HeadSettleFlag = FDCCMDADD_E;
}

static __inline__ int get_head_settle_flag( void )
{
        int     tmp = HeadSettleFlag;
        HeadSettleFlag = 0;
        return( tmp );
}

  
  

/* General Interrupt Handling */

static void (*FloppyIRQHandler)( int status ) = NULL;

static void floppy_irq (int irq, void *dummy, struct pt_regs *fp)
{
        unsigned char status;
        void (*handler)( int );

        handler = FloppyIRQHandler;
        FloppyIRQHandler = NULL;

        if (handler) {
                nop();
                status = FDC_READ( FDCREG_STATUS );
                DPRINT(("FDC irq, status = %02x handler = %08lx\n",status,(unsigned long)handler));
                handler( status );
        }
        else {
                DPRINT(("FDC irq, no handler\n"));
        }
}


/* Error handling: If some error happened, retry some times, then
 * recalibrate, then try again, and fail after MAX_ERRORS.
 */

static void fd_error( void )
{
        if (IsFormatting) {
                IsFormatting = 0;
                FormatError = 1;
                wake_up( &format_wait );
                return;
        }
                
        if (!CURRENT) return;
        CURRENT->errors++;
        if (CURRENT->errors >= MAX_ERRORS) {
                printk(KERN_ERR "fd%d: too many errors.\n", SelectedDrive );
                end_request( 0 );
        }
        else if (CURRENT->errors == RECALIBRATE_ERRORS) {
                printk(KERN_WARNING "fd%d: recalibrating\n", SelectedDrive );
                if (SelectedDrive != -1)
                        SUD.track = -1;
        }
        redo_fd_request();
}



#define SET_IRQ_HANDLER(proc) do { FloppyIRQHandler = (proc); } while(0)


/* ---------- Formatting ---------- */

#define FILL(n,val)             \
    do {                        \
        memset( p, val, n );    \
        p += n;                 \
    } while(0)

static int do_format(kdev_t device, struct atari_format_descr *desc)
{
        unsigned char   *p;
        int sect, nsect;
        unsigned long   flags;
        int type, drive = MINOR(device) & 3;

        DPRINT(("do_format( dr=%d tr=%d he=%d offs=%d )\n",
                drive, desc->track, desc->head, desc->sect_offset ));

        save_flags(flags);
        cli();
        while( fdc_busy ) sleep_on( &fdc_wait );
        fdc_busy = 1;
        stdma_lock(floppy_irq, NULL);
        atari_turnon_irq( IRQ_MFP_FDC ); /* should be already, just to be sure */
        restore_flags(flags);

        type = MINOR(device) >> 2;
        if (type) {
                if (--type >= NUM_DISK_MINORS ||
                    minor2disktype[type].drive_types > DriveType) {
                        redo_fd_request();
                        return -EINVAL;
                }
                type = minor2disktype[type].index;
                UDT = &disk_type[type];
        }

        if (!UDT || desc->track >= UDT->blocks/UDT->spt/2 || desc->head >= 2) {
                redo_fd_request();
                return -EINVAL;
        }

        nsect = UDT->spt;
        p = TrackBuffer;
        /* The track buffer is used for the raw track data, so its
           contents become invalid! */
        BufferDrive = -1;
        /* stop deselect timer */
        del_timer( &motor_off_timer );

        FILL( 60 * (nsect / 9), 0x4e );
        for( sect = 0; sect < nsect; ++sect ) {
                FILL( 12, 0 );
                FILL( 3, 0xf5 );
                *p++ = 0xfe;
                *p++ = desc->track;
                *p++ = desc->head;
                *p++ = (nsect + sect - desc->sect_offset) % nsect + 1;
                *p++ = 2;
                *p++ = 0xf7;
                FILL( 22, 0x4e );
                FILL( 12, 0 );
                FILL( 3, 0xf5 );
                *p++ = 0xfb;
                FILL( 512, 0xe5 );
                *p++ = 0xf7;
                FILL( 40, 0x4e );
        }
        FILL( TrackBuffer+BUFFER_SIZE-p, 0x4e );

        IsFormatting = 1;
        FormatError = 0;
        ReqTrack = desc->track;
        ReqSide  = desc->head;
        do_fd_action( drive );

        sleep_on( &format_wait );

        redo_fd_request();
        return( FormatError ? -EIO : 0 );       
}


/* do_fd_action() is the general procedure for a fd request: All
 * required parameter settings (drive select, side select, track
 * position) are checked and set if needed. For each of these
 * parameters and the actual reading or writing exist two functions:
 * one that starts the setting (or skips it if possible) and one
 * callback for the "done" interrupt. Each done func calls the next
 * set function to propagate the request down to fd_rwsec_done().
 */

static void do_fd_action( int drive )
{
        DPRINT(("do_fd_action\n"));
        
        if (UseTrackbuffer && !IsFormatting) {
        repeat:
            if (IS_BUFFERED( drive, ReqSide, ReqTrack )) {
                if (ReqCmd == READ) {
                    copy_buffer( SECTOR_BUFFER(ReqSector), ReqData );
                    if (++ReqCnt < CURRENT->current_nr_sectors) {
                        /* read next sector */
                        setup_req_params( drive );
                        goto repeat;
                    }
                    else {
                        /* all sectors finished */
                        CURRENT->nr_sectors -= CURRENT->current_nr_sectors;
                        CURRENT->sector += CURRENT->current_nr_sectors;
                        end_request( 1 );
                        redo_fd_request();
                        return;
                    }
                }
                else {
                    /* cmd == WRITE, pay attention to track buffer
                     * consistency! */
                    copy_buffer( ReqData, SECTOR_BUFFER(ReqSector) );
                }
            }
        }

        if (SelectedDrive != drive)
                fd_select_drive( drive );
    
        if (UD.track == -1)
                fd_calibrate();
        else if (UD.track != ReqTrack << UDT->stretch)
                fd_seek();
        else if (IsFormatting)
                fd_writetrack();
        else
                fd_rwsec();
}


/* Seek to track 0 if the current track is unknown */

static void fd_calibrate( void )
{
        if (SUD.track >= 0) {
                fd_calibrate_done( 0 );
                return;
        }

        if (ATARIHW_PRESENT(FDCSPEED))
                dma_wd.fdc_speed = 0;   /* always seek with 8 Mhz */;
        DPRINT(("fd_calibrate\n"));
        SET_IRQ_HANDLER( fd_calibrate_done );
        /* we can't verify, since the speed may be incorrect */
        FDC_WRITE( FDCREG_CMD, FDCCMD_RESTORE | SUD.steprate );

        NeedSeek = 1;
        MotorOn = 1;
        START_TIMEOUT();
        /* wait for IRQ */
}


static void fd_calibrate_done( int status )
{
        DPRINT(("fd_calibrate_done()\n"));
        STOP_TIMEOUT();
    
        /* set the correct speed now */
        if (ATARIHW_PRESENT(FDCSPEED))
                dma_wd.fdc_speed = SUDT->fdc_speed;
        if (status & FDCSTAT_RECNF) {
                printk(KERN_ERR "fd%d: restore failed\n", SelectedDrive );
                fd_error();
        }
        else {
                SUD.track = 0;
                fd_seek();
        }
}
  
  
/* Seek the drive to the requested track. The drive must have been
 * calibrated at some point before this.
 */
  
static void fd_seek( void )
{
        if (SUD.track == ReqTrack << SUDT->stretch) {
                fd_seek_done( 0 );
                return;
        }

        if (ATARIHW_PRESENT(FDCSPEED)) {
                dma_wd.fdc_speed = 0;   /* always seek witch 8 Mhz */
                MFPDELAY();
        }

        DPRINT(("fd_seek() to track %d\n",ReqTrack));
        FDC_WRITE( FDCREG_DATA, ReqTrack << SUDT->stretch);
        udelay(25);
        SET_IRQ_HANDLER( fd_seek_done );
        FDC_WRITE( FDCREG_CMD, FDCCMD_SEEK | SUD.steprate );

        MotorOn = 1;
        set_head_settle_flag();
        START_TIMEOUT();
        /* wait for IRQ */
}


static void fd_seek_done( int status )
{
        DPRINT(("fd_seek_done()\n"));
        STOP_TIMEOUT();
        
        /* set the correct speed */
        if (ATARIHW_PRESENT(FDCSPEED))
                dma_wd.fdc_speed = SUDT->fdc_speed;
        if (status & FDCSTAT_RECNF) {
                printk(KERN_ERR "fd%d: seek error (to track %d)\n",
                                SelectedDrive, ReqTrack );
                /* we don't know exactly which track we are on now! */
                SUD.track = -1;
                fd_error();
        }
        else {
                SUD.track = ReqTrack << SUDT->stretch;
                NeedSeek = 0;
                if (IsFormatting)
                        fd_writetrack();
                else
                        fd_rwsec();
        }
}


/* This does the actual reading/writing after positioning the head
 * over the correct track.
 */

static int MultReadInProgress = 0;


static void fd_rwsec( void )
{
        unsigned long paddr, flags;
        unsigned int  rwflag, old_motoron;
        unsigned int track;
        
        DPRINT(("fd_rwsec(), Sec=%d, Access=%c\n",ReqSector, ReqCmd == WRITE ? 'w' : 'r' ));
        if (ReqCmd == WRITE) {
                if (ATARIHW_PRESENT(EXTD_DMA)) {
                        paddr = (unsigned long)VTOP(ReqData);
                }
                else {
                        copy_buffer( ReqData, DMABuffer );
                        paddr = PhysDMABuffer;
                }
                dma_cache_maintenance( paddr, 512, 1 );
                rwflag = 0x100;
        }
        else {
                if (read_track)
                        paddr = PhysTrackBuffer;
                else
                        paddr = ATARIHW_PRESENT(EXTD_DMA) ? VTOP(ReqData) : PhysDMABuffer;
                rwflag = 0;
        }

        fd_select_side( ReqSide );
  
        /* Start sector of this operation */
        FDC_WRITE( FDCREG_SECTOR, read_track ? 1 : ReqSector );
        MFPDELAY();
        /* Cheat for track if stretch != 0 */
        if (SUDT->stretch) {
                track = FDC_READ( FDCREG_TRACK);
                MFPDELAY();
                FDC_WRITE( FDCREG_TRACK, track >> SUDT->stretch);
        }
        udelay(25);
  
        /* Setup DMA */
        save_flags(flags);  
        cli();
        dma_wd.dma_lo = (unsigned char)paddr;
        MFPDELAY();
        paddr >>= 8;
        dma_wd.dma_md = (unsigned char)paddr;
        MFPDELAY();
        paddr >>= 8;
        if (ATARIHW_PRESENT(EXTD_DMA))
                st_dma_ext_dmahi = (unsigned short)paddr;
        else
                dma_wd.dma_hi = (unsigned char)paddr;
        MFPDELAY();
        restore_flags(flags);
  
        /* Clear FIFO and switch DMA to correct mode */  
        dma_wd.dma_mode_status = 0x90 | rwflag;  
        MFPDELAY();
        dma_wd.dma_mode_status = 0x90 | (rwflag ^ 0x100);  
        MFPDELAY();
        dma_wd.dma_mode_status = 0x90 | rwflag;
        MFPDELAY();
  
        /* How many sectors for DMA */
        dma_wd.fdc_acces_seccount = read_track ? SUDT->spt : 1;
  
        udelay(25);  
  
        /* Start operation */
        dma_wd.dma_mode_status = FDCSELREG_STP | rwflag;
        udelay(25);
        SET_IRQ_HANDLER( fd_rwsec_done );
        dma_wd.fdc_acces_seccount =
          (get_head_settle_flag() |
           (rwflag ? FDCCMD_WRSEC : (FDCCMD_RDSEC | (read_track ? FDCCMDADD_M : 0))));

        old_motoron = MotorOn;
        MotorOn = 1;
        NeedSeek = 1;
        /* wait for interrupt */

        if (read_track) {
                /* If reading a whole track, wait about one disk rotation and
                 * then check if all sectors are read. The FDC will even
                 * search for the first non-existent sector and need 1 sec to
                 * recognise that it isn't present :-(
                 */
                del_timer (&readtrack_timer);
                readtrack_timer.expires =
                  jiffies + HZ/5 + (old_motoron ? 0 : HZ);
                       /* 1 rot. + 5 rot.s if motor was off  */
                MultReadInProgress = 1;
                add_timer( &readtrack_timer );
        }
        START_TIMEOUT();
}

    
static void fd_readtrack_check( unsigned long dummy )
{
        unsigned long flags, addr, addr2;

        save_flags(flags);  
        cli();

        del_timer( &readtrack_timer );

        if (!MultReadInProgress) {
                /* This prevents a race condition that could arise if the
                 * interrupt is triggered while the calling of this timer
                 * callback function takes place. The IRQ function then has
                 * already cleared 'MultReadInProgress'  when flow of control
                 * gets here.
                 */
                restore_flags(flags);
                return;
        }

        /* get the current DMA address */
        /* ++ f.a. read twice to avoid being fooled by switcher */
        addr = 0;
        do {
                addr2 = addr;
                addr = dma_wd.dma_lo & 0xff;
                MFPDELAY();
                addr |= (dma_wd.dma_md & 0xff) << 8;
                MFPDELAY();
                if (ATARIHW_PRESENT( EXTD_DMA ))
                        addr |= (st_dma_ext_dmahi & 0xffff) << 16;
                else
                        addr |= (dma_wd.dma_hi & 0xff) << 16;
                MFPDELAY();
        } while(addr != addr2);
  
        if (addr >= PhysTrackBuffer + SUDT->spt*512) {
                /* already read enough data, force an FDC interrupt to stop
                 * the read operation
                 */
                SET_IRQ_HANDLER( NULL );
                MultReadInProgress = 0;
                restore_flags(flags);
                DPRINT(("fd_readtrack_check(): done\n"));
                FDC_WRITE( FDCREG_CMD, FDCCMD_FORCI );
                udelay(25);

                /* No error until now -- the FDC would have interrupted
                 * otherwise!
                 */
                fd_rwsec_done1(0);
        }
        else {
                /* not yet finished, wait another tenth rotation */
                restore_flags(flags);
                DPRINT(("fd_readtrack_check(): not yet finished\n"));
                readtrack_timer.expires = jiffies + HZ/5/10;
                add_timer( &readtrack_timer );
        }
}


static void fd_rwsec_done( int status )
{
        DPRINT(("fd_rwsec_done()\n"));

        if (read_track) {
                del_timer(&readtrack_timer);
                if (!MultReadInProgress)
                        return;
                MultReadInProgress = 0;
        }
        fd_rwsec_done1(status);
}

static void fd_rwsec_done1(int status)
{
        unsigned int track;

        STOP_TIMEOUT();
        
        /* Correct the track if stretch != 0 */
        if (SUDT->stretch) {
                track = FDC_READ( FDCREG_TRACK);
                MFPDELAY();
                FDC_WRITE( FDCREG_TRACK, track << SUDT->stretch);
        }

        if (!UseTrackbuffer) {
                dma_wd.dma_mode_status = 0x90;
                MFPDELAY();
                if (!(dma_wd.dma_mode_status & 0x01)) {
                        printk(KERN_ERR "fd%d: DMA error\n", SelectedDrive );
                        goto err_end;
                }
        }
        MFPDELAY();

        if (ReqCmd == WRITE && (status & FDCSTAT_WPROT)) {
                printk(KERN_NOTICE "fd%d: is write protected\n", SelectedDrive );
                goto err_end;
        }       
        if ((status & FDCSTAT_RECNF) &&
            /* RECNF is no error after a multiple read when the FDC
               searched for a non-existent sector! */
            !(read_track && FDC_READ(FDCREG_SECTOR) > SUDT->spt)) {
                if (Probing) {
                        if (SUDT > disk_type) {
                            if (SUDT[-1].blocks > ReqBlock) {
                                /* try another disk type */
                                SUDT--;
                                floppy_sizes[SelectedDrive] = SUDT->blocks >> 1;
                            } else
                                Probing = 0;
                        }
                        else {
                                if (SUD.flags & FTD_MSG)
                                        printk(KERN_INFO "fd%d: Auto-detected floppy type %s\n",
                                               SelectedDrive, SUDT->name );
                                Probing=0;
                        }
                } else {        
/* record not found, but not probing. Maybe stretch wrong ? Restart probing */
                        if (SUD.autoprobe) {
                                SUDT = disk_type + StartDiskType[DriveType];
                                floppy_sizes[SelectedDrive] = SUDT->blocks >> 1;
                                Probing = 1;
                        }
                }
                if (Probing) {
                        if (ATARIHW_PRESENT(FDCSPEED)) {
                                dma_wd.fdc_speed = SUDT->fdc_speed;
                                MFPDELAY();
                        }
                        setup_req_params( SelectedDrive );
                        BufferDrive = -1;
                        do_fd_action( SelectedDrive );
                        return;
                }

                printk(KERN_ERR "fd%d: sector %d not found (side %d, track %d)\n",
                       SelectedDrive, FDC_READ (FDCREG_SECTOR), ReqSide, ReqTrack );
                goto err_end;
        }
        if (status & FDCSTAT_CRC) {
                printk(KERN_ERR "fd%d: CRC error (side %d, track %d, sector %d)\n",
                       SelectedDrive, ReqSide, ReqTrack, FDC_READ (FDCREG_SECTOR) );
                goto err_end;
        }
        if (status & FDCSTAT_LOST) {
                printk(KERN_ERR "fd%d: lost data (side %d, track %d, sector %d)\n",
                       SelectedDrive, ReqSide, ReqTrack, FDC_READ (FDCREG_SECTOR) );
                goto err_end;
        }

        Probing = 0;
        
        if (ReqCmd == READ) {
                if (!read_track) {
                        void *addr;
                        addr = ATARIHW_PRESENT( EXTD_DMA ) ? ReqData : DMABuffer;
                        dma_cache_maintenance( VTOP(addr), 512, 0 );
                        if (!ATARIHW_PRESENT( EXTD_DMA ))
                                copy_buffer (addr, ReqData);
                } else {
                        dma_cache_maintenance( PhysTrackBuffer, MaxSectors[DriveType] * 512, 0 );
                        BufferDrive = SelectedDrive;
                        BufferSide  = ReqSide;
                        BufferTrack = ReqTrack;
                        copy_buffer (SECTOR_BUFFER (ReqSector), ReqData);
                }
        }
  
        if (++ReqCnt < CURRENT->current_nr_sectors) {
                /* read next sector */
                setup_req_params( SelectedDrive );
                do_fd_action( SelectedDrive );
        }
        else {
                /* all sectors finished */
                CURRENT->nr_sectors -= CURRENT->current_nr_sectors;
                CURRENT->sector += CURRENT->current_nr_sectors;
                end_request( 1 );
                redo_fd_request();
        }
        return;
  
  err_end:
        BufferDrive = -1;
        fd_error();
}


static void fd_writetrack( void )
{
        unsigned long paddr, flags;
        unsigned int track;
        
        DPRINT(("fd_writetrack() Tr=%d Si=%d\n", ReqTrack, ReqSide ));

        paddr = PhysTrackBuffer;
        dma_cache_maintenance( paddr, BUFFER_SIZE, 1 );

        fd_select_side( ReqSide );
  
        /* Cheat for track if stretch != 0 */
        if (SUDT->stretch) {
                track = FDC_READ( FDCREG_TRACK);
                MFPDELAY();
                FDC_WRITE(FDCREG_TRACK,track >> SUDT->stretch);
        }
        udelay(40);
  
        /* Setup DMA */
        save_flags(flags);  
        cli();
        dma_wd.dma_lo = (unsigned char)paddr;
        MFPDELAY();
        paddr >>= 8;
        dma_wd.dma_md = (unsigned char)paddr;
        MFPDELAY();
        paddr >>= 8;
        if (ATARIHW_PRESENT( EXTD_DMA ))
                st_dma_ext_dmahi = (unsigned short)paddr;
        else
                dma_wd.dma_hi = (unsigned char)paddr;
        MFPDELAY();
        restore_flags(flags);
  
        /* Clear FIFO and switch DMA to correct mode */  
        dma_wd.dma_mode_status = 0x190;  
        MFPDELAY();
        dma_wd.dma_mode_status = 0x90;  
        MFPDELAY();
        dma_wd.dma_mode_status = 0x190;
        MFPDELAY();
  
        /* How many sectors for DMA */
        dma_wd.fdc_acces_seccount = BUFFER_SIZE/512;
        udelay(40);  
  
        /* Start operation */
        dma_wd.dma_mode_status = FDCSELREG_STP | 0x100;
        udelay(40);
        SET_IRQ_HANDLER( fd_writetrack_done );
        dma_wd.fdc_acces_seccount = FDCCMD_WRTRA | get_head_settle_flag(); 

        MotorOn = 1;
        START_TIMEOUT();
        /* wait for interrupt */
}


static void fd_writetrack_done( int status )
{
        DPRINT(("fd_writetrack_done()\n"));

        STOP_TIMEOUT();

        if (status & FDCSTAT_WPROT) {
                printk(KERN_NOTICE "fd%d: is write protected\n", SelectedDrive );
                goto err_end;
        }       
        if (status & FDCSTAT_LOST) {
                printk(KERN_ERR "fd%d: lost data (side %d, track %d)\n",
                                SelectedDrive, ReqSide, ReqTrack );
                goto err_end;
        }

        wake_up( &format_wait );
        return;

  err_end:
        fd_error();
}

static void fd_times_out( unsigned long dummy )
{
        atari_disable_irq( IRQ_MFP_FDC );
        if (!FloppyIRQHandler) goto end; /* int occurred after timer was fired, but
                                          * before we came here... */

        SET_IRQ_HANDLER( NULL );
        /* If the timeout occurred while the readtrack_check timer was
         * active, we need to cancel it, else bad things will happen */
        if (UseTrackbuffer)
                del_timer( &readtrack_timer );
        FDC_WRITE( FDCREG_CMD, FDCCMD_FORCI );
        udelay( 25 );
        
        printk(KERN_ERR "floppy timeout\n" );
        fd_error();
  end:
        atari_enable_irq( IRQ_MFP_FDC );
}


/* The (noop) seek operation here is needed to make the WP bit in the
 * FDC status register accessible for check_change. If the last disk
 * operation would have been a RDSEC, this bit would always read as 0
 * no matter what :-( To save time, the seek goes to the track we're
 * already on.
 */

static void finish_fdc( void )
{
        if (!NeedSeek) {
                finish_fdc_done( 0 );
        }
        else {
                DPRINT(("finish_fdc: dummy seek started\n"));
                FDC_WRITE (FDCREG_DATA, SUD.track);
                SET_IRQ_HANDLER( finish_fdc_done );
                FDC_WRITE (FDCREG_CMD, FDCCMD_SEEK);
                MotorOn = 1;
                START_TIMEOUT();
                /* we must wait for the IRQ here, because the ST-DMA
                   is released immediately afterwards and the interrupt
                   may be delivered to the wrong driver. */
          }
}


static void finish_fdc_done( int dummy )
{
        unsigned long flags;

        DPRINT(("finish_fdc_done entered\n"));
        STOP_TIMEOUT();
        NeedSeek = 0;

        if ((timer_active & (1 << FLOPPY_TIMER)) &&
            timer_table[FLOPPY_TIMER].expires < jiffies + 5)
                /* If the check for a disk change is done too early after this
                 * last seek command, the WP bit still reads wrong :-((
                 */
                timer_table[FLOPPY_TIMER].expires = jiffies + 5;
        else
                START_CHECK_CHANGE_TIMER( CHECK_CHANGE_DELAY );
        del_timer( &motor_off_timer );
        START_MOTOR_OFF_TIMER( FD_MOTOR_OFF_DELAY );

        save_flags(flags);
        cli();
        stdma_release();
        fdc_busy = 0;
        wake_up( &fdc_wait );
        restore_flags(flags);

        DPRINT(("finish_fdc() finished\n"));
}


/* Prevent "aliased" accesses. */
static int fd_ref[4] = { 0,0,0,0 };
static int fd_device[4] = { 0,0,0,0 };

/*
 * Current device number. Taken either from the block header or from the
 * format request descriptor.
 */
#define CURRENT_DEVICE (CURRENT->rq_dev)

/* Current error count. */
#define CURRENT_ERRORS (CURRENT->errors)


/* dummy for blk.h */
static void floppy_off( unsigned int nr) {}


/* The detection of disk changes is a dark chapter in Atari history :-(
 * Because the "Drive ready" signal isn't present in the Atari
 * hardware, one has to rely on the "Write Protect". This works fine,
 * as long as no write protected disks are used. TOS solves this
 * problem by introducing tri-state logic ("maybe changed") and
 * looking at the serial number in block 0. This isn't possible for
 * Linux, since the floppy driver can't make assumptions about the
 * filesystem used on the disk and thus the contents of block 0. I've
 * chosen the method to always say "The disk was changed" if it is
 * unsure whether it was. This implies that every open or mount
 * invalidates the disk buffers if you work with write protected
 * disks. But at least this is better than working with incorrect data
 * due to unrecognised disk changes.
 */

static int check_floppy_change (kdev_t dev)
{
        unsigned int drive = MINOR(dev) & 0x03;

        if (MAJOR(dev) != MAJOR_NR) {
                printk(KERN_ERR "floppy_changed: not a floppy\n");
                return 0;
        }
        
        if (test_bit (drive, &fake_change)) {
                /* simulated change (e.g. after formatting) */
                return 1;
        }
        if (test_bit (drive, &changed_floppies)) {
                /* surely changed (the WP signal changed at least once) */
                return 1;
        }
        if (UD.wpstat) {
                /* WP is on -> could be changed: to be sure, buffers should be
                 * invalidated...
                 */
                return 1;
        }

        return 0;
}

static int floppy_revalidate (kdev_t dev)
{
        int drive = MINOR(dev) & 3;

        if (test_bit(drive, &changed_floppies) ||
            test_bit(drive, &fake_change) ||
            unit[drive].disktype == 0) {
                if (UD.flags & FTD_MSG)
                        printk(KERN_ERR "floppy: clear format %p!\n", UDT);
                BufferDrive = -1;
                clear_bit(drive, &fake_change);
                clear_bit(drive, &changed_floppies);
                /* MSch: clearing geometry makes sense only for autoprobe
                   formats, for 'permanent user-defined' parameter:
                   restore default_params[] here if flagged valid! */
                if (default_params[drive].blocks == 0)
                        UDT = 0;
                else
                        UDT = &default_params[drive];
        }
        return 0;
}

static __inline__ void copy_buffer(void *from, void *to)
{
        ulong   *p1 = (ulong *)from, *p2 = (ulong *)to;
        int             cnt;

        for( cnt = 512/4; cnt; cnt-- )
                *p2++ = *p1++;
}


/* This sets up the global variables describing the current request. */

static void setup_req_params( int drive )
{
        int block = ReqBlock + ReqCnt;

        ReqTrack = block / UDT->spt;
        ReqSector = block - ReqTrack * UDT->spt + 1;
        ReqSide = ReqTrack & 1;
        ReqTrack >>= 1;
        ReqData = ReqBuffer + 512 * ReqCnt;

        if (UseTrackbuffer)
                read_track = (ReqCmd == READ && CURRENT_ERRORS == 0);
        else
                read_track = 0;

        DPRINT(("Request params: Si=%d Tr=%d Se=%d Data=%08lx\n",ReqSide,
                        ReqTrack, ReqSector, (unsigned long)ReqData ));
}


static void redo_fd_request(void)
{
        int device, drive, type;
  
        DPRINT(("redo_fd_request: CURRENT=%08lx CURRENT->dev=%04x CURRENT->sector=%ld\n",
                (unsigned long)CURRENT, CURRENT ? CURRENT->rq_dev : 0,
                CURRENT ? CURRENT->sector : 0 ));

        IsFormatting = 0;

        if (CURRENT && CURRENT->rq_status == RQ_INACTIVE){
                return;
        }

repeat:
    
        if (!CURRENT)
                goto the_end;

        if (MAJOR(CURRENT->rq_dev) != MAJOR_NR)
                panic(DEVICE_NAME ": request list destroyed");

        if (CURRENT->bh && !buffer_locked(CURRENT->bh))
                panic(DEVICE_NAME ": block not locked");

        device = MINOR(CURRENT_DEVICE);
        drive = device & 3;
        type = device >> 2;
        
        if (!UD.connected) {
                /* drive not connected */
                printk(KERN_ERR "Unknown Device: fd%d\n", drive );
                end_request(0);
                goto repeat;
        }
                
        if (type == 0) {
                if (!UDT) {
                        Probing = 1;
                        UDT = disk_type + StartDiskType[DriveType];
                        floppy_sizes[drive] = UDT->blocks >> 1;
                        UD.autoprobe = 1;
                }
        } 
        else {
                /* user supplied disk type */
                if (--type >= NUM_DISK_MINORS) {
                        printk(KERN_WARNING "fd%d: invalid disk format", drive );
                        end_request( 0 );
                        goto repeat;
                }
                if (minor2disktype[type].drive_types > DriveType)  {
                        printk(KERN_WARNING "fd%d: unsupported disk format", drive );
                        end_request( 0 );
                        goto repeat;
                }
                type = minor2disktype[type].index;
                UDT = &disk_type[type];
                floppy_sizes[drive] = UDT->blocks >> 1;
                UD.autoprobe = 0;
        }
        
        if (CURRENT->sector + 1 > UDT->blocks) {
                end_request(0);
                goto repeat;
        }

        /* stop deselect timer */
        del_timer( &motor_off_timer );
                
        ReqCnt = 0;
        ReqCmd = CURRENT->cmd;
        ReqBlock = CURRENT->sector;
        ReqBuffer = CURRENT->buffer;
        setup_req_params( drive );
        do_fd_action( drive );

        return;

  the_end:
        finish_fdc();
}


void do_fd_request(void)
{
        unsigned long flags;

        DPRINT(("do_fd_request for pid %d\n",current->pid));
        while( fdc_busy ) sleep_on( &fdc_wait );
        fdc_busy = 1;
        stdma_lock(floppy_irq, NULL);

        atari_disable_irq( IRQ_MFP_FDC );
        save_flags(flags);      /* The request function is called with ints
        sti();                           * disabled... so must save the IPL for later */ 
        redo_fd_request();
        restore_flags(flags);
        atari_enable_irq( IRQ_MFP_FDC );
}


static int invalidate_drive(kdev_t rdev)
{
        /* invalidate the buffer track to force a reread */
        BufferDrive = -1;
        set_bit(MINOR(rdev) & 3, &fake_change);
        check_disk_change(rdev);
        return 0;
}

static int fd_ioctl(struct inode *inode, struct file *filp,
                    unsigned int cmd, unsigned long param)
{
#define IOCTL_MODE_BIT 8
#define OPEN_WRITE_BIT 16
#define IOCTL_ALLOWED (filp && (filp->f_mode & IOCTL_MODE_BIT))

        int drive, type;
        kdev_t device;
        struct atari_format_descr fmt_desc;
        struct atari_disk_type *dtp;
        struct floppy_struct getprm;
        int settype;
        struct floppy_struct setprm;

        device = inode->i_rdev;
        switch (cmd) {
                RO_IOCTLS (device, param);
        }
        drive = MINOR (device);
        type  = drive >> 2;
        drive &= 3;
        switch (cmd) {
        case FDGETPRM:
        case BLKGETSIZE:
                if (type) {
                        if (--type >= NUM_DISK_MINORS)
                                return -ENODEV;
                        if (minor2disktype[type].drive_types > DriveType)
                                return -ENODEV;
                        type = minor2disktype[type].index;
                        dtp = &disk_type[type];
                        if (UD.flags & FTD_MSG)
                            printk (KERN_ERR "floppy%d: found dtp %p name %s!\n",
                                drive, dtp, dtp->name);
                }
                else {
                        if (!UDT)
                                return -ENXIO;
                        else
                                dtp = UDT;
                }
                if (cmd == BLKGETSIZE)
                        return put_user(dtp->blocks, (long *)param);

                memset((void *)&getprm, 0, sizeof(getprm));
                getprm.size = dtp->blocks;
                getprm.sect = dtp->spt;
                getprm.head = 2;
                getprm.track = dtp->blocks/dtp->spt/2;
                getprm.stretch = dtp->stretch;
                if (copy_to_user((void *)param, &getprm, sizeof(getprm)))
                        return -EFAULT;
                return 0;
        case BLKRASET:
                if (!capable(CAP_SYS_ADMIN))
                        return -EACCES;
                if (param > 0xff)
                        return -EINVAL;
                read_ahead[MAJOR(inode->i_rdev)] = param;
                return 0;
        case BLKRAGET:
                return put_user(read_ahead[MAJOR(inode->i_rdev)],
                                (int *) param);
        case BLKFLSBUF:
                if (!capable(CAP_SYS_ADMIN))
                        return -EACCES;
                fsync_dev(inode->i_rdev);
                invalidate_buffers(inode->i_rdev);
                return 0;
        }
        if (!IOCTL_ALLOWED)
                return -EPERM;
        switch (cmd) {
        case FDSETPRM:
        case FDDEFPRM:
                /* 
                 * MSch 7/96: simple 'set geometry' case: just set the
                 * 'default' device params (minor == 0).
                 * Currently, the drive geometry is cleared after each
                 * disk change and subsequent revalidate()! simple
                 * implementation of FDDEFPRM: save geometry from a
                 * FDDEFPRM call and restore it in floppy_revalidate() !
                 */

                /* get the parameters from user space */
                if (fd_ref[drive] != 1 && fd_ref[drive] != -1)
                        return -EBUSY;
                if (copy_from_user(&setprm, (void *) param, sizeof(setprm)))
                        return -EFAULT;
                /* 
                 * first of all: check for floppy change and revalidate, 
                 * or the next access will revalidate - and clear UDT :-(
                 */

                if (check_floppy_change(device))
                        floppy_revalidate(device);

                if (UD.flags & FTD_MSG)
                    printk (KERN_INFO "floppy%d: setting size %d spt %d str %d!\n",
                        drive, setprm.size, setprm.sect, setprm.stretch);

                /* what if type > 0 here? Overwrite specified entry ? */
                if (type) {
                        /* refuse to re-set a predefined type for now */
                        redo_fd_request();
                        return -EINVAL;
                }

                /* 
                 * type == 0: first look for a matching entry in the type list,
                 * and set the UD.disktype field to use the perdefined entry.
                 * TODO: add user-defined format to head of autoprobe list ? 
                 * Useful to include the user-type for future autodetection!
                 */

                for (settype = 0; settype < NUM_DISK_MINORS; settype++) {
                        int setidx = 0;
                        if (minor2disktype[settype].drive_types > DriveType) {
                                /* skip this one, invalid for drive ... */
                                continue;
                        }
                        setidx = minor2disktype[settype].index;
                        dtp = &disk_type[setidx];

                        /* found matching entry ?? */
                        if (   dtp->blocks  == setprm.size 
                            && dtp->spt     == setprm.sect
                            && dtp->stretch == setprm.stretch ) {
                                if (UD.flags & FTD_MSG)
                                    printk (KERN_INFO "floppy%d: setting %s %p!\n",
                                        drive, dtp->name, dtp);
                                UDT = dtp;
                                floppy_sizes[drive] = UDT->blocks >> 1;

                                if (cmd == FDDEFPRM) {
                                  /* save settings as permanent default type */
                                  default_params[drive].name    = dtp->name;
                                  default_params[drive].spt     = dtp->spt;
                                  default_params[drive].blocks  = dtp->blocks;
                                  default_params[drive].fdc_speed = dtp->fdc_speed;
                                  default_params[drive].stretch = dtp->stretch;
                                }
                                
                                return 0;
                        }

                }

                /* no matching disk type found above - setting user_params */

                if (cmd == FDDEFPRM) {
                        /* set permanent type */
                        dtp = &default_params[drive];
                } else
                        /* set user type (reset by disk change!) */
                        dtp = &user_params[drive];

                dtp->name   = "user format";
                dtp->blocks = setprm.size;
                dtp->spt    = setprm.sect;
                if (setprm.sect > 14) 
                        dtp->fdc_speed = 3;
                else
                        dtp->fdc_speed = 0;
                dtp->stretch = setprm.stretch;

                if (UD.flags & FTD_MSG)
                        printk (KERN_INFO "floppy%d: blk %d spt %d str %d!\n",
                                drive, dtp->blocks, dtp->spt, dtp->stretch);

                /* sanity check */
                if (!dtp || setprm.track != dtp->blocks/dtp->spt/2 ||
                    setprm.head != 2) {
                        redo_fd_request();
                        return -EINVAL;
                }

                UDT = dtp;
                floppy_sizes[drive] = UDT->blocks >> 1;

                return 0;
        case FDMSGON:
                UD.flags |= FTD_MSG;
                return 0;
        case FDMSGOFF:
                UD.flags &= ~FTD_MSG;
                return 0;
        case FDSETEMSGTRESH:
                return -EINVAL;
        case FDFMTBEG:
                return 0;
        case FDFMTTRK:
                if (fd_ref[drive] != 1 && fd_ref[drive] != -1)
                        return -EBUSY;
                if (copy_from_user(&fmt_desc, (void *) param, sizeof(fmt_desc)))
                        return -EFAULT;
                return do_format(device, &fmt_desc);
        case FDCLRPRM:
                UDT = NULL;
                /* MSch: invalidate default_params */
                default_params[drive].blocks  = 0;
                floppy_sizes[drive] = MAX_DISK_SIZE;
                return invalidate_drive (device);
        case FDFMTEND:
        case FDFLUSH:
                return invalidate_drive(device);
        }
        return -EINVAL;
}


/* Initialize the 'unit' variable for drive 'drive' */

__initfunc(static void fd_probe( int drive ))
{
        UD.connected = 0;
        UDT  = NULL;

        if (!fd_test_drive_present( drive ))
                return;

        UD.connected = 1;
        UD.track     = 0;
        switch( UserSteprate[drive] ) {
        case 2:
                UD.steprate = FDCSTEP_2;
                break;
        case 3:
                UD.steprate = FDCSTEP_3;
                break;
        case 6:
                UD.steprate = FDCSTEP_6;
                break;
        case 12:
                UD.steprate = FDCSTEP_12;
                break;
        default: /* should be -1 for "not set by user" */
                if (ATARIHW_PRESENT( FDCSPEED ) || MACH_IS_MEDUSA)
                        UD.steprate = FDCSTEP_3;
                else
                        UD.steprate = FDCSTEP_6;
                break;
        }
        MotorOn = 1;    /* from probe restore operation! */
}


/* This function tests the physical presence of a floppy drive (not
 * whether a disk is inserted). This is done by issuing a restore
 * command, waiting max. 2 seconds (that should be enough to move the
 * head across the whole disk) and looking at the state of the "TR00"
 * signal. This should now be raised if there is a drive connected
 * (and there is no hardware failure :-) Otherwise, the drive is
 * declared absent.
 */

__initfunc(static int fd_test_drive_present( int drive ))
{
        unsigned long timeout;
        unsigned char status;
        int ok;
        
        if (drive >= (MACH_IS_FALCON ? 1 : 2)) return( 0 );
        fd_select_drive( drive );

        /* disable interrupt temporarily */
        atari_turnoff_irq( IRQ_MFP_FDC );
        FDC_WRITE (FDCREG_TRACK, 0xff00);
        FDC_WRITE( FDCREG_CMD, FDCCMD_RESTORE | FDCCMDADD_H | FDCSTEP_6 );

        for( ok = 0, timeout = jiffies + 2*HZ+HZ/2; jiffies < timeout; ) {
                if (!(mfp.par_dt_reg & 0x20))
                        break;
        }

        status = FDC_READ( FDCREG_STATUS );
        ok = (status & FDCSTAT_TR00) != 0;

        /* force interrupt to abort restore operation (FDC would try
         * about 50 seconds!) */
        FDC_WRITE( FDCREG_CMD, FDCCMD_FORCI );
        udelay(500);
        status = FDC_READ( FDCREG_STATUS );
        udelay(20);

        if (ok) {
                /* dummy seek command to make WP bit accessible */
                FDC_WRITE( FDCREG_DATA, 0 );
                FDC_WRITE( FDCREG_CMD, FDCCMD_SEEK );
                while( mfp.par_dt_reg & 0x20 )
                        ;
                status = FDC_READ( FDCREG_STATUS );
        }

        atari_turnon_irq( IRQ_MFP_FDC );
        return( ok );
}


/* Look how many and which kind of drives are connected. If there are
 * floppies, additionally start the disk-change and motor-off timers.
 */

__initfunc(static void config_types( void ))
{
        int drive, cnt = 0;

        /* for probing drives, set the FDC speed to 8 MHz */
        if (ATARIHW_PRESENT(FDCSPEED))
                dma_wd.fdc_speed = 0;

        printk(KERN_INFO "Probing floppy drive(s):\n");
        for( drive = 0; drive < FD_MAX_UNITS; drive++ ) {
                fd_probe( drive );
                if (UD.connected) {
                        printk(KERN_INFO "fd%d\n", drive);
                        ++cnt;
                }
        }

        if (FDC_READ( FDCREG_STATUS ) & FDCSTAT_BUSY) {
                /* If FDC is still busy from probing, give it another FORCI
                 * command to abort the operation. If this isn't done, the FDC
                 * will interrupt later and its IRQ line stays low, because
                 * the status register isn't read. And this will block any
                 * interrupts on this IRQ line :-(
                 */
                FDC_WRITE( FDCREG_CMD, FDCCMD_FORCI );
                udelay(500);
                FDC_READ( FDCREG_STATUS );
                udelay(20);
        }
        
        if (cnt > 0) {
                START_MOTOR_OFF_TIMER( FD_MOTOR_OFF_DELAY );
                if (cnt == 1) fd_select_drive( 0 );
                START_CHECK_CHANGE_TIMER( CHECK_CHANGE_DELAY );
        }
}

/*
 * floppy_open check for aliasing (/dev/fd0 can be the same as
 * /dev/PS0 etc), and disallows simultaneous access to the same
 * drive with different device numbers.
 */

static int floppy_open( struct inode *inode, struct file *filp )
{
        int drive, type;
        int old_dev;

        if (!filp) {
                DPRINT (("Weird, open called with filp=0\n"));
                return -EIO;
        }

        drive = MINOR(inode->i_rdev) & 3;
        type  = MINOR(inode->i_rdev) >> 2;
        DPRINT(("fd_open: type=%d\n",type));
        if (drive >= FD_MAX_UNITS || type > NUM_DISK_MINORS)
                return -ENXIO;

        old_dev = fd_device[drive];

        if (fd_ref[drive] && old_dev != MINOR(inode->i_rdev))
                return -EBUSY;

        if (fd_ref[drive] == -1 || (fd_ref[drive] && filp->f_flags & O_EXCL))
                return -EBUSY;

        MOD_INC_USE_COUNT;

        if (filp->f_flags & O_EXCL)
                fd_ref[drive] = -1;
        else
                fd_ref[drive]++;

        fd_device[drive] = MINOR(inode->i_rdev);

        if (old_dev && old_dev != MINOR(inode->i_rdev))
                invalidate_buffers(MKDEV(FLOPPY_MAJOR, old_dev));

        /* Allow ioctls if we have write-permissions even if read-only open */
        if (filp->f_mode & 2 || permission (inode, 2) == 0)
                filp->f_mode |= IOCTL_MODE_BIT;
        if (filp->f_mode & 2)
                filp->f_mode |= OPEN_WRITE_BIT;

        if (filp->f_flags & O_NDELAY)
                return 0;

        if (filp->f_mode & 3) {
                check_disk_change(inode->i_rdev);
                if (filp->f_mode & 2) {
                        if (UD.wpstat) {
                                floppy_release(inode, filp);
                                return -EROFS;
                        }
                }
        }

        return 0;
}


static int floppy_release( struct inode * inode, struct file * filp )
{
        int drive;

        drive = MINOR(inode->i_rdev) & 3;

        /*
         * If filp is NULL, we're being called from blkdev_release
         * or after a failed mount attempt.  In the former case the
         * device has already been sync'ed, and in the latter no
         * sync is required.  Otherwise, sync if filp is writable.
         */
        if (filp && (filp->f_mode & (2 | OPEN_WRITE_BIT)))
                block_fsync (filp, filp->f_dentry);

        if (fd_ref[drive] < 0)
                fd_ref[drive] = 0;
        else if (!fd_ref[drive]--) {
                printk(KERN_ERR "floppy_release with fd_ref == 0");
                fd_ref[drive] = 0;
        }

        MOD_DEC_USE_COUNT;
        return 0;
}

static struct file_operations floppy_fops = {
        NULL,                   /* lseek - default */
        block_read,             /* read - general block-dev read */
        block_write,            /* write - general block-dev write */
        NULL,                   /* readdir - bad */
        NULL,                   /* select */
        fd_ioctl,               /* ioctl */
        NULL,                   /* mmap */
        floppy_open,            /* open */
        NULL,                   /* flush */
        floppy_release,         /* release */
        block_fsync,            /* fsync */
        NULL,                   /* fasync */
        check_floppy_change,    /* media_change */
        floppy_revalidate,      /* revalidate */
};

__initfunc(int atari_floppy_init (void))
{
        int i;

        if (!MACH_IS_ATARI)
                /* Amiga, Mac, ... don't have Atari-compatible floppy :-) */
                return -ENXIO;

        if (MACH_IS_HADES)
                /* Hades doesn't have Atari-compatible floppy */
                return -ENXIO;

        if (register_blkdev(MAJOR_NR,"fd",&floppy_fops)) {
                printk(KERN_ERR "Unable to get major %d for floppy\n",MAJOR_NR);
                return -EBUSY;
        }

        if (UseTrackbuffer < 0)
                /* not set by user -> use default: for now, we turn
                   track buffering off for all Medusas, though it
                   could be used with ones that have a counter
                   card. But the test is too hard :-( */
                UseTrackbuffer = !MACH_IS_MEDUSA;

        /* initialize variables */
        SelectedDrive = -1;
        BufferDrive = -1;

        /* initialize check_change timer */
        timer_table[FLOPPY_TIMER].fn = check_change;
        timer_active &= ~(1 << FLOPPY_TIMER);

        DMABuffer = atari_stram_alloc( BUFFER_SIZE+512, NULL, "ataflop" );
        if (!DMABuffer) {
                printk(KERN_ERR "atari_floppy_init: cannot get dma buffer\n");
                unregister_blkdev(MAJOR_NR, "fd");
                return -ENOMEM;
        }
        TrackBuffer = DMABuffer + 512;
        PhysDMABuffer = (unsigned long) VTOP(DMABuffer);
        PhysTrackBuffer = (unsigned long) VTOP(TrackBuffer);
        BufferDrive = BufferSide = BufferTrack = -1;

        for (i = 0; i < FD_MAX_UNITS; i++) {
                unit[i].track = -1;
                unit[i].flags = 0;
        }

        for (i = 0; i < 256; i++)
                if ((i >> 2) > 0 && (i >> 2) <= NUM_DISK_MINORS) {
                        int type = minor2disktype[(i >> 2) - 1].index;
                        floppy_sizes[i] = disk_type[type].blocks >> 1;
                } else
                        floppy_sizes[i] = MAX_DISK_SIZE;

        blk_size[MAJOR_NR] = floppy_sizes;
        blksize_size[MAJOR_NR] = floppy_blocksizes;
        blk_dev[MAJOR_NR].request_fn = DEVICE_REQUEST;

        printk(KERN_INFO "Atari floppy driver: max. %cD, %strack buffering\n",
               DriveType == 0 ? 'D' : DriveType == 1 ? 'H' : 'E',
               UseTrackbuffer ? "" : "no ");
        config_types();

        (void)do_floppy; /* avoid warning about unused variable */
        return 0;
}


__initfunc(void atari_floppy_setup( char *str, int *ints ))
{
        int i;
        
        if (ints[0] < 1) {
                printk(KERN_ERR "ataflop_setup: no arguments!\n" );
                return;
        }
        else if (ints[0] > 2+FD_MAX_UNITS) {
                printk(KERN_ERR "ataflop_setup: too many arguments\n" );
        }

        if (ints[1] < 0 || ints[1] > 2)
                printk(KERN_ERR "ataflop_setup: bad drive type\n" );
        else
                DriveType = ints[1];

        if (ints[0] >= 2)
                UseTrackbuffer = (ints[2] > 0);

        for( i = 3; i <= ints[0] && i-3 < FD_MAX_UNITS; ++i ) {
                if (ints[i] != 2 && ints[i] != 3 && ints[i] != 6 && ints[i] != 12)
                        printk(KERN_ERR "ataflop_setup: bad steprate\n" );
                else
                        UserSteprate[i-3] = ints[i];
        }
}

#ifdef MODULE
int init_module (void)
{
        if (!MACH_IS_ATARI)
                return -ENXIO;
        return atari_floppy_init ();
}

void cleanup_module (void)
{
        unregister_blkdev(MAJOR_NR, "fd");

        blk_dev[MAJOR_NR].request_fn = 0;
        timer_active &= ~(1 << FLOPPY_TIMER);
        timer_table[FLOPPY_TIMER].fn = 0;
        atari_stram_free( DMABuffer );
}
#endif