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File: [cvs.NetBSD.org] / src / sys / arch / atari / dev / fd.c (download)

Revision 1.83, Fri Jan 2 19:42:05 2015 UTC (2 months ago) by christos
Branch: MAIN
CVS Tags: HEAD
Changes since 1.82: +3 -3 lines

We have three sets of DTYPE_ constants in the kernel:
	altq		Drop 		Type
	disklabel	Disk 		Type
	file		Descriptor	Type
(not to mention constants that contain the string DTYPE).
Let's make them two, by changing the disklabel one to be DisK TYPE since the
other disklabel constants seem to do that. Not many userland programs use
these constants (and the ones that they do are mostly in ifdefs). They will
be fixed shortly.

/*	$NetBSD: fd.c,v 1.83 2015/01/02 19:42:05 christos Exp $	*/

/*
 * Copyright (c) 1995 Leo Weppelman.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * This file contains a driver for the Floppy Disk Controller (FDC)
 * on the Atari TT. It uses the WD 1772 chip, modified for steprates.
 *
 * The ST floppy disk controller shares the access to the DMA circuitry
 * with other devices. For this reason the floppy disk controller makes
 * use of some special DMA accessing code.
 *
 * Interrupts from the FDC are in fact DMA interrupts which get their
 * first level handling in 'dma.c' . If the floppy driver is currently
 * using DMA the interrupt is signalled to 'fdcint'.
 *
 * TODO:
 *   - Test it with 2 drives (I don't have them)
 *   - Test it with an HD-drive (Don't have that either)
 *   - Finish ioctl's
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: fd.c,v 1.83 2015/01/02 19:42:05 christos Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/callout.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/buf.h>
#include <sys/bufq.h>
#include <sys/proc.h>
#include <sys/device.h>
#include <sys/ioctl.h>
#include <sys/fcntl.h>
#include <sys/conf.h>
#include <sys/disklabel.h>
#include <sys/disk.h>
#include <sys/dkbad.h>
#include <atari/atari/device.h>
#include <atari/atari/stalloc.h>
#include <machine/disklabel.h>
#include <machine/iomap.h>
#include <machine/mfp.h>
#include <machine/dma.h>
#include <machine/video.h>
#include <machine/cpu.h>
#include <atari/dev/ym2149reg.h>
#include <atari/dev/fdreg.h>

#include "ioconf.h"

/*
 * Be verbose for debugging
 */
/*#define FLP_DEBUG	1 */

#define	FDC_MAX_DMA_AD	0x1000000	/* No DMA possible beyond	*/

/* Parameters for the disk drive. */
#define SECTOR_SIZE	512	/* physical sector size in bytes	*/
#define NR_DRIVES	2	/* maximum number of drives		*/
#define NR_TYPES	3	/* number of diskette/drive combinations*/
#define MAX_ERRORS	10	/* how often to try rd/wt before quitting*/
#define STEP_DELAY	6000	/* 6ms (6000us) delay after stepping	*/


#define	INV_TRK		32000	/* Should fit in unsigned short		*/
#define	INV_PART	NR_TYPES

/*
 * Driver states
 */
#define	FLP_IDLE	0x00	/* floppy is idle			*/
#define	FLP_MON		0x01	/* idle with motor on			*/
#define	FLP_STAT	0x02	/* determine floppy status		*/
#define	FLP_XFER	0x04	/* read/write data from floppy		*/

/*
 * Timer delay's
 */
#define	FLP_MONDELAY	(3 * hz)	/* motor-on delay		*/
#define	FLP_XFERDELAY	(2 * hz)	/* timeout on transfer		*/

/*
 * The density codes
 */
#define	FLP_DD		0		/* Double density		*/
#define	FLP_HD		1		/* High density			*/


#define	b_block		b_resid		/* FIXME: this is not the place	*/

/*
 * Global data for all physical floppy devices
 */
static short	selected = 0;		/* drive/head currently selected*/
static short	motoron  = 0;		/* motor is spinning		*/
static short	nopens   = 0;		/* Number of opens executed	*/

static short	fd_state = FLP_IDLE;	/* Current driver state		*/
static int	lock_stat = 0;		/* DMA locking status		*/
static short	fd_cmd   = 0;		/* command being executed	*/
static const char *fd_error = NULL;	/* error from fd_xfer_ok()	*/

/*
 * Private per device data
 */
struct fd_softc {
	device_t	sc_dev;		/* generic device info		*/
	struct disk	dkdev;		/* generic disk info		*/
	struct bufq_state *bufq;	/* queue of buf's		*/
	struct callout	sc_motor_ch;
	int		unit;		/* unit for atari controlling hw*/
	int		nheads;		/* number of heads in use	*/
	int		nsectors;	/* number of sectors/track	*/
	int		density;	/* density code			*/
	int		nblocks;	/* number of blocks on disk	*/
	int		curtrk;		/* track head positioned on	*/
	short		flags;		/* misc flags			*/
	short		part;		/* Current open partition	*/
	int		sector;		/* logical sector for I/O	*/
	uint8_t		*io_data;	/* KVA for data transfer	*/
	int		io_bytes;	/* bytes left for I/O		*/
	int		io_dir;		/* B_READ/B_WRITE		*/
	int		errcnt;		/* current error count		*/
	uint8_t		*bounceb;	/* Bounce buffer		*/

};

/*
 * Flags in fd_softc:
 */
#define FLPF_NOTRESP	0x001		/* Unit not responding		*/
#define FLPF_ISOPEN	0x002		/* Unit is open			*/
#define FLPF_SPARE	0x004		/* Not used			*/
#define FLPF_HAVELAB	0x008		/* We have a valid label	*/
#define FLPF_BOUNCE	0x010		/* Now using the bounce buffer	*/
#define FLPF_WRTPROT	0x020		/* Unit is write-protected	*/
#define FLPF_EMPTY	0x040		/* Unit is empty		*/
#define FLPF_INOPEN	0x080		/* Currently being opened	*/
#define FLPF_GETSTAT	0x100		/* Getting unit status		*/

struct fd_types {
	int		nheads;		/* Heads in use			*/
	int		nsectors;	/* sectors per track		*/
	int		nblocks;	/* number of blocks		*/
	int		density;	/* density code			*/
	const char	*descr;		/* type description		*/
} fdtypes[NR_TYPES] = {
		{ 1,  9,  720 , FLP_DD , "360KB" },	/* 360  Kb	*/
		{ 2,  9, 1440 , FLP_DD , "720KB" },	/* 720  Kb	*/
		{ 2, 18, 2880 , FLP_HD , "1.44MB" },	/* 1.44 Mb	*/
};

#define	FLP_TYPE_360	0		/* XXX: Please keep these in	*/
#define	FLP_TYPE_720	1		/* sync with the numbering in	*/
#define	FLP_TYPE_144	2		/* 'fdtypes' right above!	*/

/*
 * This is set only once at attach time. The value is determined by reading
 * the configuration switches and is one of the FLP_TYPE_*'s. 
 * This is simular to the way Atari handles the _FLP cookie.
 */
static short	def_type = 0;		/* Reflects config-switches	*/

#define	FLP_DEFTYPE	1		/* 720Kb, reasonable default	*/
#define	FLP_TYPE(dev)	( DISKPART(dev) == 0 ? def_type : DISKPART(dev) - 1 )

typedef void	(*FPV)(void *);

dev_type_open(fdopen);
dev_type_close(fdclose);
dev_type_read(fdread);
dev_type_write(fdwrite);
dev_type_ioctl(fdioctl);
dev_type_strategy(fdstrategy);

/*
 * Private drive functions....
 */
static void	fdstart(struct fd_softc *);
static void	fddone(struct fd_softc *);
static void	fdstatus(struct fd_softc *);
static void	fd_xfer(struct fd_softc *);
static void	fdcint(struct fd_softc *);
static int	fd_xfer_ok(struct fd_softc *);
static void	fdmotoroff(struct fd_softc *);
static void	fdminphys(struct buf *);
static void	fdtestdrv(struct fd_softc *);
static void	fdgetdefaultlabel(struct fd_softc *, struct disklabel *,
		    int);
static int	fdgetdisklabel(struct fd_softc *, dev_t);
static int	fdselect(int, int, int);
static void	fddeselect(void);
static void	fdmoff(struct fd_softc *);

static u_short rd_cfg_switch(void);

static inline uint8_t	read_fdreg(u_short);
static inline void	write_fdreg(u_short, u_short);
static inline uint8_t	read_dmastat(void);

static inline
uint8_t read_fdreg(u_short regno)
{

	DMA->dma_mode = regno;
	return DMA->dma_data;
}

static inline
void write_fdreg(u_short regno, u_short val)
{

	DMA->dma_mode = regno;
	DMA->dma_data = val;
}

static inline
uint8_t read_dmastat(void)
{

	DMA->dma_mode = FDC_CS | DMA_SCREG;
	return DMA->dma_stat;
}

/*
 * Config switch stuff. Used only for the floppy type for now. That's
 * why it's here...
 * XXX: If needed in more places, it should be moved to its own include file.
 * Note: This location _must_ be read as an u_short. Failure to do so
 *       will return garbage!
 */
static u_short
rd_cfg_switch(void)
{

	return *(volatile u_short *)AD_CFG_SWITCH;
}

/*
 * Switch definitions.
 * Note: ON reads as a zero bit!
 */
#define	CFG_SWITCH_NOHD	0x4000

/*
 * Autoconfig stuff....
 */
static int	fdcmatch(device_t, cfdata_t, void *);
static int	fdcprint(void *, const char *);
static void	fdcattach(device_t, device_t, void *);

CFATTACH_DECL_NEW(fdc, 0,
    fdcmatch, fdcattach, NULL, NULL);

const struct bdevsw fd_bdevsw = {
	.d_open = fdopen,
	.d_close = fdclose,
	.d_strategy = fdstrategy,
	.d_ioctl = fdioctl,
	.d_dump = nodump,
	.d_psize = nosize,
	.d_discard = nodiscard,
	.d_flag = D_DISK
};

const struct cdevsw fd_cdevsw = {
	.d_open = fdopen,
	.d_close = fdclose,
	.d_read = fdread,
	.d_write = fdwrite,
	.d_ioctl = fdioctl,
	.d_stop = nostop,
	.d_tty = notty,
	.d_poll = nopoll,
	.d_mmap = nommap,
	.d_kqfilter = nokqfilter,
	.d_discard = nodiscard,
	.d_flag = D_DISK
};

static int
fdcmatch(device_t parent, cfdata_t match, void *aux)
{
	static int fdc_matched = 0;

	/* Match only once */
	if (strcmp("fdc", aux) || fdc_matched)
		return 0;
	fdc_matched = 1;
	return 1;
}

static void
fdcattach(device_t parent, device_t self, void *aux)
{
	struct fd_softc	fdsoftc;
	int i, nfound, first_found;

	nfound = first_found = 0;
	printf("\n");
	fddeselect();
	for (i = 0; i < NR_DRIVES; i++) {

		/*
		 * Test if unit is present
		 */
		fdsoftc.unit  = i;
		fdsoftc.flags = 0;
		st_dmagrab((dma_farg)fdcint, (dma_farg)fdtestdrv, &fdsoftc,
		    &lock_stat, 0);
		st_dmafree(&fdsoftc, &lock_stat);

		if ((fdsoftc.flags & FLPF_NOTRESP) == 0) {
			if (nfound == 0)
				first_found = i;
			nfound++;
			config_found(self, (void *)i, fdcprint);
		}
	}

	if (nfound != 0) {
		struct fd_softc *fdsc =
		    device_lookup_private(&fd_cd, first_found);

		/*
		 * Make sure motor will be turned of when a floppy is
		 * inserted in the first selected drive.
		 */
		fdselect(first_found, 0, FLP_DD);
		fd_state = FLP_MON;
		callout_reset(&fdsc->sc_motor_ch, 0, (FPV)fdmotoroff, fdsc);

		/*
		 * enable disk related interrupts
		 */
		MFP->mf_ierb |= IB_DINT;
		MFP->mf_iprb  = (uint8_t)~IB_DINT;
		MFP->mf_imrb |= IB_DINT;
	}
}

static int
fdcprint(void *aux, const char *pnp)
{

	if (pnp != NULL)
		aprint_normal("fd%d at %s:", (int)aux, pnp);
	
	return UNCONF;
}

static int	fdmatch(device_t, cfdata_t, void *);
static void	fdattach(device_t, device_t, void *);

struct dkdriver fddkdriver = { fdstrategy };

CFATTACH_DECL_NEW(fd, sizeof(struct fd_softc),
    fdmatch, fdattach, NULL, NULL);

static int
fdmatch(device_t parent, cfdata_t match, void *aux)
{

	return 1;
}

static void
fdattach(device_t parent, device_t self, void *aux)
{
	struct fd_softc	*sc;
	struct fd_types *type;
	u_short		swtch;

	sc = device_private(self);
	sc->sc_dev = self;

	callout_init(&sc->sc_motor_ch, 0);

	/*
	 * Find out if an Ajax chip might be installed. Set the default
	 * floppy type accordingly.
	 */
	swtch    = rd_cfg_switch();
	def_type = (swtch & CFG_SWITCH_NOHD) ? FLP_TYPE_720 : FLP_TYPE_144;
	type     = &fdtypes[def_type];

	aprint_normal(": %s %d cyl, %d head, %d sec\n", type->descr,
	    type->nblocks / (type->nsectors * type->nheads), type->nheads,
	    type->nsectors);

	/*
	 * Initialize and attach the disk structure.
	 */
	disk_init(&sc->dkdev, device_xname(sc->sc_dev), &fddkdriver);
	disk_attach(&sc->dkdev);
}

int
fdioctl(dev_t dev, u_long cmd, void * addr, int flag, struct lwp *l)
{
	struct fd_softc *sc;
	int error;

	sc = device_lookup_private(&fd_cd, DISKUNIT(dev));

	if ((sc->flags & FLPF_HAVELAB) == 0)
		return EBADF;

	error = disk_ioctl(&sc->dkdev, RAW_PART, cmd, addr, flag, l);
	if (error != EPASSTHROUGH)
		return error;

	switch (cmd) {
	case DIOCSBAD:
		return EINVAL;
#ifdef notyet /* XXX LWP */
	case DIOCSRETRIES:
	case DIOCSSTEP:
	case DIOCSDINFO:
	case DIOCWDINFO:
	case DIOCWLABEL:
		break;
#endif /* notyet */
	case DIOCGDEFLABEL:
		fdgetdefaultlabel(sc, (struct disklabel *)addr, RAW_PART);
		return 0;
	}
	return ENOTTY;
}

/*
 * Open the device. If this is the first open on both the floppy devices,
 * intialize the controller.
 * Note that partition info on the floppy device is used to distinguise
 * between 780Kb and 360Kb floppy's.
 *	partition 0: 360Kb
 *	partition 1: 780Kb
 */
int
fdopen(dev_t dev, int flags, int devtype, struct lwp *l)
{
	struct fd_softc	*sc;
	int s;

#ifdef FLP_DEBUG
	printf("fdopen dev=0x%x\n", dev);
#endif

	if (FLP_TYPE(dev) >= NR_TYPES)
		return ENXIO;

	if ((sc = device_lookup_private(&fd_cd, DISKUNIT(dev))) == NULL)
		return ENXIO;

	/*
	 * If no floppy currently open, reset the controller and select
	 * floppy type.
	 */
	if (nopens == 0) {

#ifdef FLP_DEBUG
		printf("fdopen device not yet open\n");
#endif
		nopens++;
		write_fdreg(FDC_CS, IRUPT);
		delay(40);
	}

	/*
	 * Sleep while other process is opening the device
	 */
	s = splbio();
	while (sc->flags & FLPF_INOPEN)
		tsleep((void *)sc, PRIBIO, "fdopen", 0);
	splx(s);

	if ((sc->flags & FLPF_ISOPEN) == 0) {
		/*
		 * Initialise some driver values.
		 */
		int type;
		void *addr;

		type = FLP_TYPE(dev);

		bufq_alloc(&sc->bufq, "disksort", BUFQ_SORT_RAWBLOCK);
		sc->unit        = DISKUNIT(dev);
		sc->part        = RAW_PART;
		sc->nheads	= fdtypes[type].nheads;
		sc->nsectors	= fdtypes[type].nsectors;
		sc->nblocks     = fdtypes[type].nblocks;
		sc->density	= fdtypes[type].density;
		sc->curtrk	= INV_TRK;
		sc->sector	= 0;
		sc->errcnt	= 0;
		sc->bounceb	= alloc_stmem(SECTOR_SIZE, &addr);
		if (sc->bounceb == NULL)
			return ENOMEM; /* XXX */

		/*
		 * Go get write protect + loaded status
		 */
		sc->flags |= FLPF_INOPEN|FLPF_GETSTAT;
		s = splbio();
		st_dmagrab((dma_farg)fdcint, (dma_farg)fdstatus, sc,
		    &lock_stat, 0);
		while ((sc->flags & FLPF_GETSTAT) != 0)
			tsleep((void *)sc, PRIBIO, "fdopen", 0);
		splx(s);
		wakeup((void *)sc);

		if ((sc->flags & FLPF_WRTPROT) != 0 &&
		    (flags & FWRITE) != 0) {
			sc->flags = 0;
			return EPERM;
		}
		if ((sc->flags & FLPF_EMPTY) != 0) {
			sc->flags = 0;
			return ENXIO;
		}
		sc->flags &= ~(FLPF_INOPEN|FLPF_GETSTAT);
		sc->flags |= FLPF_ISOPEN;
	} else {
		/*
		 * Multiply opens are granted when accessing the same type of
		 * floppy (eq. the same partition).
		 */
		if (sc->density != fdtypes[DISKPART(dev)].density)
			return ENXIO;	/* XXX temporarely out of business */
	}
	fdgetdisklabel(sc, dev);
#ifdef FLP_DEBUG
	printf("fdopen open succeeded on type %d\n", sc->part);
#endif
	return 0;
}

int
fdclose(dev_t dev, int flags, int devtype, struct lwp *l)
{
	struct fd_softc	*sc;

	sc = device_lookup_private(&fd_cd, DISKUNIT(dev));
	free_stmem(sc->bounceb);
	sc->flags = 0;
	nopens--;

#ifdef FLP_DEBUG
	printf("Closed floppy device -- nopens: %d\n", nopens);
#endif
	return 0;
}

void
fdstrategy(struct buf *bp)
{
	struct fd_softc *sc;
	struct disklabel *lp;
	int s, sz;

	sc = device_lookup_private(&fd_cd, DISKUNIT(bp->b_dev));

#ifdef FLP_DEBUG
	printf("fdstrategy: %p, b_bcount: %ld\n", bp, bp->b_bcount);
#endif

	/*
	 * check for valid partition and bounds
	 */
	lp = sc->dkdev.dk_label;
	if ((sc->flags & FLPF_HAVELAB) == 0) {
		bp->b_error = EIO;
		goto done;
	}
	if (bp->b_blkno < 0 || (bp->b_bcount % SECTOR_SIZE) != 0) {
		bp->b_error = EINVAL;
		goto done;
	}
	if (bp->b_bcount == 0)
		goto done;

	sz = howmany(bp->b_bcount, SECTOR_SIZE);

	if (bp->b_blkno + sz > sc->nblocks) {
		sz = sc->nblocks - bp->b_blkno;
		if (sz == 0) /* Exactly at EndOfDisk */
			goto done;
		if (sz < 0) { /* Past EndOfDisk */
			bp->b_error = EINVAL;
			goto done;
		}
		/* Trucate it */
		if (bp->b_flags & B_RAW)
			bp->b_bcount = sz << DEV_BSHIFT;
		else
			bp->b_bcount = sz * lp->d_secsize;
	}

	/* No partition translation. */
	bp->b_rawblkno = bp->b_blkno;

	/*
	 * queue the buf and kick the low level code
	 */
	s = splbio();
	bufq_put(sc->bufq, bp);	/* XXX disksort_cylinder */
	if (!lock_stat) {
		if (fd_state & FLP_MON)
			callout_stop(&sc->sc_motor_ch);
		fd_state = FLP_IDLE;
		st_dmagrab((dma_farg)fdcint, (dma_farg)fdstart, sc,
		    &lock_stat, 0);
	}
	splx(s);

	return;
done:
	bp->b_resid = bp->b_bcount;
	biodone(bp);
}

int
fdread(dev_t dev, struct uio *uio, int flags)
{

	return physio(fdstrategy, NULL, dev, B_READ, fdminphys, uio);
}

int
fdwrite(dev_t dev, struct uio *uio, int flags)
{

	return physio(fdstrategy, NULL, dev, B_WRITE, fdminphys, uio);
}

/*
 * Called through DMA-dispatcher, get status.
 */
static void
fdstatus(struct fd_softc *sc)
{

#ifdef FLP_DEBUG
	printf("fdstatus\n");
#endif
	sc->errcnt = 0;
	fd_state   = FLP_STAT;
	fd_xfer(sc);
}

/*
 * Called through the DMA-dispatcher. So we know we are the only ones
 * messing with the floppy-controller.
 * Initialize some fields in the fdsoftc for the state-machine and get
 * it going.
 */
static void
fdstart(struct fd_softc *sc)
{
	struct buf *bp;

	bp	     = bufq_peek(sc->bufq);
	sc->sector   = bp->b_blkno;	/* Start sector for I/O		*/
	sc->io_data  = bp->b_data;	/* KVA base for I/O		*/
	sc->io_bytes = bp->b_bcount;	/* Transfer size in bytes	*/
	sc->io_dir   = bp->b_flags & B_READ;/* Direction of transfer	*/
	sc->errcnt   = 0;		/* No errors yet		*/
	fd_state     = FLP_XFER;	/* Yes, we're going to transfer	*/

	/* Instrumentation. */
	disk_busy(&sc->dkdev);

	fd_xfer(sc);
}

/*
 * The current transaction is finished (for good or bad). Let go of
 * the DMA-resources. Call biodone() to finish the transaction.
 * Find a new transaction to work on.
 */
static void
fddone(register struct fd_softc *sc)
{
	struct buf *bp;
	struct fd_softc	*sc1;
	int i, s;

	/*
	 * Give others a chance to use the DMA.
	 */
	st_dmafree(sc, &lock_stat);


	if (fd_state != FLP_STAT) {
		/*
		 * Finish current transaction.
		 */
		s = splbio();
		bp = bufq_get(sc->bufq);
		if (bp == NULL)
			panic("fddone");
		splx(s);

#ifdef FLP_DEBUG
		printf("fddone: unit: %d, buf: %p, resid: %d\n",sc->unit, bp,
		    sc->io_bytes);
#endif
		bp->b_resid = sc->io_bytes;

		disk_unbusy(&sc->dkdev, (bp->b_bcount - bp->b_resid),
		    (bp->b_flags & B_READ));

		biodone(bp);
	}
	fd_state = FLP_MON;

	if (lock_stat)
		return;		/* XXX Is this possible?	*/

	/*
	 * Find a new transaction on round-robin basis.
	 */
	for (i = sc->unit + 1;; i++) {
		if (i >= fd_cd.cd_ndevs)
			i = 0;
		if ((sc1 = device_lookup_private(&fd_cd, i)) == NULL)
			continue;
		if (bufq_peek(sc1->bufq) != NULL)
			break;
		if (i == sc->unit) {
			callout_reset(&sc->sc_motor_ch, FLP_MONDELAY,
			    (FPV)fdmotoroff, sc);
#ifdef FLP_DEBUG
			printf("fddone: Nothing to do\n");
#endif
			return;	/* No work */
		}
	}
	fd_state = FLP_IDLE;
#ifdef FLP_DEBUG
	printf("fddone: Staring job on unit %d\n", sc1->unit);
#endif
	st_dmagrab((dma_farg)fdcint, (dma_farg)fdstart, sc1, &lock_stat, 0);
}

static int
fdselect(int drive, int head, int dense)
{
	int i, spinning;

#ifdef FLP_DEBUG
	printf("fdselect: drive=%d, head=%d, dense=%d\n", drive, head, dense);
#endif
	i = ((drive == 1) ? PA_FLOP1 : PA_FLOP0) | head;
	spinning = motoron;
	motoron  = 1;

	switch (dense) {
	case FLP_DD:
		DMA->dma_drvmode = 0;
		break;
	case FLP_HD:
		DMA->dma_drvmode = (FDC_HDSET|FDC_HDSIG);
		break;
	default:
		panic("fdselect: unknown density code");
	}
	if (i != selected) {
		selected = i;
		ym2149_fd_select((i ^ PA_FDSEL));
	}
	return spinning;
}

static void
fddeselect(void)
{

	ym2149_fd_select(PA_FDSEL);
	motoron = selected = 0;
	DMA->dma_drvmode   = 0;
}

/****************************************************************************
 * The following functions assume to be running as a result of a            *
 * disk-interrupt (e.q. spl = splbio).				            *
 * They form the finit-state machine, the actual driver.                    *
 *                                                                          *
 *	fdstart()/ --> fd_xfer() -> activate hardware                       *
 *  fdopen()          ^                                                     *
 *                    |                                                     *
 *                    +-- not ready -<------------+                         *
 *                                                |                         *
 *  fdmotoroff()/ --> fdcint() -> fd_xfer_ok() ---+                         *
 *  h/w interrupt                 |                                         *
 *                               \|/                                        *
 *                            finished ---> fdone()                         *
 *                                                                          *
 ****************************************************************************/
static void
fd_xfer(struct fd_softc *sc)
{
	int head;
	int track, sector, hbit;
	paddr_t phys_addr;

	head = track = 0;
	switch (fd_state) {
	case FLP_XFER:
		/*
		 * Calculate head/track values
		 */
		track  = sc->sector / sc->nsectors;
		head   = track % sc->nheads;
		track  = track / sc->nheads;
#ifdef FLP_DEBUG
		printf("fd_xfer: sector:%d,head:%d,track:%d\n",
		    sc->sector, head, track);
#endif
		break;

	case FLP_STAT:
		/*
		 * FLP_STAT only wants to recalibrate
		 */
		sc->curtrk = INV_TRK;
		break;
	default:
		panic("fd_xfer: wrong state (0x%x)", fd_state);
	}

	/*
	 * Select the drive.
	 */
	hbit = fdselect(sc->unit, head, sc->density) ? HBIT : 0;

	if (sc->curtrk == INV_TRK) {
		/*
		 * Recalibrate, since we lost track of head positioning.
		 * The floppy disk controller has no way of determining its
		 * absolute arm position (track).  Instead, it steps the
		 * arm a track at a time and keeps track of where it
		 * thinks it is (in software).  However, after a SEEK, the
		 * hardware reads information from the diskette telling
		 * where the arm actually is.  If the arm is in the wrong place,
		 * a recalibration is done, which forces the arm to track 0.
		 * This way the controller can get back into sync with reality.
		 */
		fd_cmd = RESTORE;
		write_fdreg(FDC_CS, RESTORE|VBIT|hbit);
		callout_reset(&sc->sc_motor_ch, FLP_XFERDELAY,
		    (FPV)fdmotoroff, sc);

#ifdef FLP_DEBUG
		printf("fd_xfer:Recalibrating drive %d\n", sc->unit);
#endif
		return;
	}

	write_fdreg(FDC_TR, sc->curtrk);

	/*
	 * Issue a SEEK command on the indicated drive unless the arm is
	 * already positioned on the correct track.
	 */
	if (track != sc->curtrk) {
		sc->curtrk = track;	/* be optimistic */
		write_fdreg(FDC_DR, track);
		write_fdreg(FDC_CS, SEEK|RATE6|VBIT|hbit);
		callout_reset(&sc->sc_motor_ch, FLP_XFERDELAY,
		    (FPV)fdmotoroff, sc);
		fd_cmd = SEEK;
#ifdef FLP_DEBUG
		printf("fd_xfer:Seek to track %d on drive %d\n",
		    track, sc->unit);
#endif
		return;
	}

	/*
	 * The drive is now on the proper track. Read or write 1 block.
	 */
	sector = sc->sector % sc->nsectors;
	sector++;	/* start numbering at 1 */

	write_fdreg(FDC_SR, sector);

	phys_addr = (paddr_t)kvtop(sc->io_data);
	if (phys_addr >= FDC_MAX_DMA_AD) {
		/*
		 * We _must_ bounce this address
		 */
		phys_addr = (paddr_t)kvtop(sc->bounceb);
		if (sc->io_dir == B_WRITE)
			memcpy(sc->bounceb, sc->io_data, SECTOR_SIZE);
		sc->flags |= FLPF_BOUNCE;
	}
	st_dmaaddr_set((void *)phys_addr);	/* DMA address setup */

#ifdef FLP_DEBUG
	printf("fd_xfer:Start io (io_addr:%lx)\n", (u_long)kvtop(sc->io_data));
#endif

	if (sc->io_dir == B_READ) {
		/* Issue the command */
		st_dmacomm(DMA_FDC | DMA_SCREG, 1);
		write_fdreg(FDC_CS, F_READ|hbit);
		fd_cmd = F_READ;
	} else {
		/* Issue the command */
		st_dmacomm(DMA_WRBIT | DMA_FDC | DMA_SCREG, 1);
		write_fdreg(DMA_WRBIT | FDC_CS, F_WRITE|hbit|EBIT|PBIT);
		fd_cmd = F_WRITE;
	}
	callout_reset(&sc->sc_motor_ch, FLP_XFERDELAY, (FPV)fdmotoroff, sc);
}

/* return values of fd_xfer_ok(): */
#define X_OK			0
#define X_AGAIN			1
#define X_ERROR			2
#define X_FAIL			3

/*
 * Hardware interrupt function.
 */
static void
fdcint(struct fd_softc *sc)
{
	struct buf *bp;

#ifdef FLP_DEBUG
	printf("fdcint: unit = %d\n", sc->unit);
#endif

	/*
	 * Cancel timeout (we made it, didn't we)
	 */
	callout_stop(&sc->sc_motor_ch);

	switch (fd_xfer_ok(sc)) {
	case X_ERROR:
		if (++sc->errcnt < MAX_ERRORS) {
			/*
			 * Command failed but still retries left.
			 */
			break;
		}
		/* FALL THROUGH */
	case X_FAIL:
		/*
		 * Non recoverable error. Fall back to motor-on
		 * idle-state.
		 */
		if (fd_error != NULL) {
			printf("Floppy error: %s\n", fd_error);
			fd_error = NULL;
		}

		if (fd_state == FLP_STAT) {
			sc->flags |= FLPF_EMPTY;
			sc->flags &= ~FLPF_GETSTAT;
			wakeup((void *)sc);
			fddone(sc);
			return;
		}

		bp = bufq_peek(sc->bufq);

		bp->b_error  = EIO;
		fd_state     = FLP_MON;

		break;
	case X_AGAIN:
		/*
		 * Start next part of state machine.
		 */
		break;
	case X_OK:
		/*
		 * Command ok and finished. Reset error-counter.
		 * If there are no more bytes to transfer fall back
		 * to motor-on idle state.
		 */
		sc->errcnt = 0;

		if (fd_state == FLP_STAT) {
			sc->flags &= ~FLPF_GETSTAT;
			wakeup((void *)sc);
			fddone(sc);
			return;
		}

		if ((sc->flags & FLPF_BOUNCE) != 0 &&
		    sc->io_dir == B_READ)
			memcpy(sc->io_data, sc->bounceb, SECTOR_SIZE);
		sc->flags &= ~FLPF_BOUNCE;

		sc->sector++;
		sc->io_data  += SECTOR_SIZE;
		sc->io_bytes -= SECTOR_SIZE;
		if (sc->io_bytes <= 0)
			fd_state = FLP_MON;
	}
	if (fd_state == FLP_MON)
		fddone(sc);
	else
		fd_xfer(sc);
}

/*
 * Determine status of last command. Should only be called through
 * 'fdcint()'.
 * Returns:
 *	X_ERROR : Error on command; might succeed next time.
 *	X_FAIL  : Error on command; will never succeed.
 *	X_AGAIN : Part of a command succeeded, call 'fd_xfer()' to complete.
 *	X_OK	: Command succeeded and is complete.
 *
 * This function only affects sc->curtrk.
 */
static int
fd_xfer_ok(register struct fd_softc *sc)
{
	int status;

#ifdef FLP_DEBUG
	printf("fd_xfer_ok: cmd: 0x%x, state: 0x%x\n", fd_cmd, fd_state);
#endif
	switch (fd_cmd) {
	case IRUPT:
		/*
		 * Timeout. Force a recalibrate before we try again.
		 */
		status = read_fdreg(FDC_CS);

		fd_error = "Timeout";
		sc->curtrk = INV_TRK;
		return X_ERROR;
	case F_READ:
		/*
		 * Test for DMA error
		 */
		status = read_dmastat();
		if ((status & DMAOK) == 0) {
			fd_error = "DMA error";
			return X_ERROR;
		}
		/*
		 * Get controller status and check for errors.
		 */
		status = read_fdreg(FDC_CS);
		if ((status & (RNF | CRCERR | LD_T00)) != 0) {
			fd_error = "Read error";
			if ((status & RNF) != 0)
				sc->curtrk = INV_TRK;
			return X_ERROR;
		}
		break;
	case F_WRITE:
		/*
		 * Test for DMA error
		 */
		status = read_dmastat();
		if ((status & DMAOK) == 0) {
			fd_error = "DMA error";
			return X_ERROR;
		}
		/*
		 * Get controller status and check for errors.
		 */
		status = read_fdreg(FDC_CS);
		if ((status & WRI_PRO) != 0) {
			fd_error = "Write protected";
			return X_FAIL;
		}
		if ((status & (RNF | CRCERR | LD_T00)) != 0) {
			fd_error = "Write error";
			sc->curtrk = INV_TRK;
			return X_ERROR;
		}
		break;
	case SEEK:
		status = read_fdreg(FDC_CS);
		if ((status & (RNF | CRCERR)) != 0) {
			fd_error = "Seek error";
			sc->curtrk = INV_TRK;
			return X_ERROR;
		}
		return X_AGAIN;
	case RESTORE:
		/*
		 * Determine if the recalibration succeeded.
		 */
		status = read_fdreg(FDC_CS);
		if ((status & RNF) != 0) {
			fd_error = "Recalibrate error";
			/* reset controller */
			write_fdreg(FDC_CS, IRUPT);
			sc->curtrk = INV_TRK;
			return X_ERROR;
		}
		sc->curtrk = 0;
		if (fd_state == FLP_STAT) {
			if ((status & WRI_PRO) != 0)
				sc->flags |= FLPF_WRTPROT;
			break;
		}
		return X_AGAIN;
	default:
		fd_error = "Driver error: fd_xfer_ok : Unknown state";
		return X_FAIL;
	}
	return X_OK;
}

/*
 * All timeouts will call this function.
 */
static void
fdmotoroff(struct fd_softc *sc)
{
	int s;

	/*
	 * Get at harware interrupt level
	 */
	s = splbio();

#if FLP_DEBUG
	printf("fdmotoroff, state = 0x%x\n", fd_state);
#endif

	switch (fd_state) {
	case FLP_STAT:
	case FLP_XFER:
		/*
		 * Timeout during a transfer; cancel transaction
		 * set command to 'IRUPT'.
		 * A drive-interrupt is simulated to trigger the state
		 * machine.
		 */
		/*
		 * Cancel current transaction
		 */
		fd_cmd = IRUPT;
		write_fdreg(FDC_CS, IRUPT);
		delay(20);
		(void)read_fdreg(FDC_CS);
		write_fdreg(FDC_CS, RESTORE);
		break;

	case FLP_MON:
		/*
		 * Turn motor off.
		 */
		if (selected) {
			int tmp;

			st_dmagrab((dma_farg)fdcint, (dma_farg)fdmoff, sc,
			    &tmp, 0);
		} else
			fd_state = FLP_IDLE;
		break;
	}
	splx(s);
}

/*
 * min byte count to whats left of the track in question
 */
static void
fdminphys(struct buf *bp)
{
	struct fd_softc	*sc;
	int sec, toff, tsz;

	if ((sc = device_lookup_private(&fd_cd, DISKUNIT(bp->b_dev))) == NULL)
		panic("fdminphys: couldn't get softc");

	sec  = bp->b_blkno % (sc->nsectors * sc->nheads);
	toff = sec * SECTOR_SIZE;
	tsz  = sc->nsectors * sc->nheads * SECTOR_SIZE;

#ifdef FLP_DEBUG
	printf("fdminphys: before %ld", bp->b_bcount);
#endif

	bp->b_bcount = min(bp->b_bcount, tsz - toff);

#ifdef FLP_DEBUG
	printf(" after %ld\n", bp->b_bcount);
#endif

	minphys(bp);
}

/*
 * Called from fdmotoroff to turn the motor actually off....
 * This can't be done in fdmotoroff itself, because exclusive access to the
 * DMA controller is needed to read the FDC-status register. The function
 * 'fdmoff()' always runs as the result of a 'dmagrab()'.
 * We need to test the status-register because we want to be sure that the
 * drive motor is really off before deselecting the drive. The FDC only
 * turns off the drive motor after having seen 10 index-pulses. You only
 * get index-pulses when a drive is selected....This means that if the
 * drive is deselected when the motor is still spinning, it will continue
 * to spin _even_ when you insert a floppy later on...
 */
static void
fdmoff(struct fd_softc *fdsoftc)
{
	int tmp;

	if ((fd_state == FLP_MON) && selected) {
		tmp = read_fdreg(FDC_CS);
		if ((tmp & MOTORON) == 0) {
			fddeselect();
			fd_state = FLP_IDLE;
		} else
			callout_reset(&fdsoftc->sc_motor_ch, 10 * FLP_MONDELAY,
			    (FPV)fdmotoroff, fdsoftc);
	}
	st_dmafree(fdsoftc, &tmp);
}

/*
 * Used to find out wich drives are actually connected. We do this by issuing
 * is 'RESTORE' command and check if the 'track-0' bit is set. This also works
 * if the drive is present but no floppy is inserted.
 */
static void
fdtestdrv(struct fd_softc *fdsoftc)
{
	int status;

	/*
	 * Select the right unit and head.
	 */
	fdselect(fdsoftc->unit, 0, FLP_DD);

	write_fdreg(FDC_CS, RESTORE|HBIT);

	/*
	 * Wait for about 2 seconds.
	 */
	delay(2000000);

	status = read_fdreg(FDC_CS);
	if ((status & (RNF|BUSY)) != 0) {
		write_fdreg(FDC_CS, IRUPT);	/* reset controller */
		delay(40);
	}

	if ((status & LD_T00) == 0)
		fdsoftc->flags |= FLPF_NOTRESP;

	fddeselect();
}

static void
fdgetdefaultlabel(struct fd_softc *sc, struct disklabel *lp, int part)
{

	memset(lp, 0, sizeof(struct disklabel));

	lp->d_secsize     = SECTOR_SIZE;
	lp->d_ntracks     = sc->nheads;
	lp->d_nsectors    = sc->nsectors;
	lp->d_secpercyl   = lp->d_ntracks * lp->d_nsectors;
	lp->d_ncylinders  = sc->nblocks / lp->d_secpercyl;
	lp->d_secperunit  = sc->nblocks;

	lp->d_type        = DKTYPE_FLOPPY;
	lp->d_rpm         = 300; 	/* good guess I suppose.	*/
	lp->d_interleave  = 1;		/* FIXME: is this OK?		*/
	lp->d_bbsize      = 0;
	lp->d_sbsize      = 0;
	lp->d_npartitions = part + 1;
	lp->d_trkseek     = STEP_DELAY;
	lp->d_magic       = DISKMAGIC;
	lp->d_magic2      = DISKMAGIC;
	lp->d_checksum    = dkcksum(lp);
	lp->d_partitions[part].p_size   = lp->d_secperunit;
	lp->d_partitions[part].p_fstype = FS_UNUSED;
	lp->d_partitions[part].p_fsize  = 1024;
	lp->d_partitions[part].p_frag   = 8;
}

/*
 * Build disk label. For now we only create a label from what we know
 * from 'sc'.
 */
static int
fdgetdisklabel(struct fd_softc *sc, dev_t dev)
{
	struct disklabel *lp;
	int part;

	/*
	 * If we already got one, get out.
	 */
	if ((sc->flags & FLPF_HAVELAB) != 0)
		return 0;

#ifdef FLP_DEBUG
	printf("fdgetdisklabel()\n");
#endif

	part = RAW_PART;
	lp   = sc->dkdev.dk_label;
	fdgetdefaultlabel(sc, lp, part);
	sc->flags |= FLPF_HAVELAB;

	return 0;
}