/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 2004 Poul-Henning Kamp
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Don Ahn.
 *
 * Libretto PCMCIA floppy support by David Horwitt (dhorwitt@ucsd.edu)
 * aided by the Linux floppy driver modifications from David Bateman
 * (dbateman@eng.uts.edu.au).
 *
 * Copyright (c) 1993, 1994 by
 *  jc@irbs.UUCP (John Capo)
 *  vak@zebub.msk.su (Serge Vakulenko)
 *  ache@astral.msk.su (Andrew A. Chernov)
 *
 * Copyright (c) 1993, 1994, 1995 by
 *  joerg_wunsch@uriah.sax.de (Joerg Wunsch)
 *  dufault@hda.com (Peter Dufault)
 *
 * Copyright (c) 2001 Joerg Wunsch,
 *  joerg_wunsch@uriah.heep.sax.de (Joerg Wunsch)
 *
 * 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.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
 *
 */

#include <sys/cdefs.h>
#include "opt_fdc.h"

#include <sys/param.h>
#include <sys/bio.h>
#include <sys/bus.h>
#include <sys/devicestat.h>
#include <sys/disk.h>
#include <sys/fcntl.h>
#include <sys/fdcio.h>
#include <sys/filio.h>
#include <sys/kernel.h>
#include <sys/kthread.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/rman.h>
#include <sys/stdarg.h>
#include <sys/sysctl.h>
#include <sys/systm.h>

#include <geom/geom.h>

#include <machine/bus.h>
#include <machine/clock.h>

#include <isa/isavar.h>
#include <isa/isareg.h>
#include <isa/rtc.h>
#include <dev/fdc/fdcvar.h>

#include <dev/ic/nec765.h>

/*
 * Runtime configuration hints/flags
 */

/* configuration flags for fd */
#define FD_TYPEMASK     0x0f    /* drive type, matches enum
                                 * fd_drivetype; on i386 machines, if
                                 * given as 0, use RTC type for fd0
                                 * and fd1 */
#define FD_NO_CHLINE    0x10    /* drive does not support changeline
                                 * aka. unit attention */
#define FD_NO_PROBE     0x20    /* don't probe drive (seek test), just
                                 * assume it is there */

/*
 * Things that could conceiveably considered parameters or tweakables
 */

/*
 * Maximal number of bytes in a cylinder.
 * This is used for ISADMA bouncebuffer allocation and sets the max
 * xfersize we support.
 *
 * 2.88M format has 2 x 36 x 512, allow for hacked up density.
 */
#define MAX_BYTES_PER_CYL       (2 * 40 * 512)

/*
 * Timeout value for the PIO loops to wait until the FDC main status
 * register matches our expectations (request for master, direction
 * bit).  This is supposed to be a number of microseconds, although
 * timing might actually not be very accurate.
 *
 * Timeouts of 100 msec are believed to be required for some broken
 * (old) hardware.
 */
#define FDSTS_TIMEOUT   100000

/*
 * After this many errors, stop whining.  Close will reset this count.
 */
#define FDC_ERRMAX      100

/*
 * AutoDensity search lists for each drive type.
 */

static struct fd_type fd_searchlist_360k[] = {
        { FDF_5_360 },
        { 0 }
};

static struct fd_type fd_searchlist_12m[] = {
        { FDF_5_1200 | FL_AUTO },
        { FDF_5_400 | FL_AUTO },
        { FDF_5_360 | FL_2STEP | FL_AUTO},
        { 0 }
};

static struct fd_type fd_searchlist_720k[] = {
        { FDF_3_720 },
        { 0 }
};

static struct fd_type fd_searchlist_144m[] = {
        { FDF_3_1440 | FL_AUTO},
        { FDF_3_720 | FL_AUTO},
        { 0 }
};

static struct fd_type fd_searchlist_288m[] = {
        { FDF_3_1440 | FL_AUTO },
#if 0
        { FDF_3_2880 | FL_AUTO }, /* XXX: probably doesn't work */
#endif
        { FDF_3_720 | FL_AUTO},
        { 0 }
};

/*
 * Order must match enum fd_drivetype in <sys/fdcio.h>.
 */
static struct fd_type *fd_native_types[] = {
        NULL,                           /* FDT_NONE */
        fd_searchlist_360k,             /* FDT_360K */
        fd_searchlist_12m,              /* FDT_12M */
        fd_searchlist_720k,             /* FDT_720K */
        fd_searchlist_144m,             /* FDT_144M */
        fd_searchlist_288m,             /* FDT_288M_1 (mapped to FDT_288M) */
        fd_searchlist_288m,             /* FDT_288M */
};

/*
 * Internals start here
 */

/* registers */
#define FDOUT   2       /* Digital Output Register (W) */
#define FDO_FDSEL       0x03    /*  floppy device select */
#define FDO_FRST        0x04    /*  floppy controller reset */
#define FDO_FDMAEN      0x08    /*  enable floppy DMA and Interrupt */
#define FDO_MOEN0       0x10    /*  motor enable drive 0 */
#define FDO_MOEN1       0x20    /*  motor enable drive 1 */
#define FDO_MOEN2       0x40    /*  motor enable drive 2 */
#define FDO_MOEN3       0x80    /*  motor enable drive 3 */

#define FDSTS   4       /* NEC 765 Main Status Register (R) */
#define FDDSR   4       /* Data Rate Select Register (W) */
#define FDDATA  5       /* NEC 765 Data Register (R/W) */
#define FDCTL   7       /* Control Register (W) */

/*
 * The YE-DATA PC Card floppies use PIO to read in the data rather
 * than DMA due to the wild variability of DMA for the PC Card
 * devices.  DMA was deleted from the PC Card specification in version
 * 7.2 of the standard, but that post-dates the YE-DATA devices by many
 * years.
 *
 * In addition, if we cannot setup the DMA resources for the ISA
 * attachment, we'll use this same offset for data transfer.  However,
 * that almost certainly won't work.
 *
 * For this mode, offset 0 and 1 must be used to setup the transfer
 * for this floppy.  This is OK for PC Card YE Data devices, but for
 * ISA this is likely wrong.  These registers are only available on
 * those systems that map them to the floppy drive.  Newer systems do
 * not do this, and we should likely prohibit access to them (or
 * disallow NODMA to be set).
 */
#define FDBCDR          0       /* And 1 */
#define FD_YE_DATAPORT  6       /* Drive Data port */

#define FDI_DCHG        0x80    /* diskette has been changed */
                                /* requires drive and motor being selected */
                                /* is cleared by any step pulse to drive */

/*
 * We have three private BIO commands.
 */
#define BIO_PROBE       BIO_CMD0
#define BIO_RDID        BIO_CMD1
#define BIO_FMT         BIO_CMD2

/*
 * Per drive structure (softc).
 */
struct fd_data {
        u_char  *fd_ioptr;      /* IO pointer */
        u_int   fd_iosize;      /* Size of IO chunks */
        u_int   fd_iocount;     /* Outstanding requests */
        struct  fdc_data *fdc;  /* pointer to controller structure */
        int     fdsu;           /* this units number on this controller */
        enum    fd_drivetype type; /* drive type */
        struct  fd_type *ft;    /* pointer to current type descriptor */
        struct  fd_type fts;    /* type descriptors */
        int     sectorsize;
        int     flags;
#define FD_WP           (1<<0)  /* Write protected      */
#define FD_MOTOR        (1<<1)  /* motor should be on   */
#define FD_MOTORWAIT    (1<<2)  /* motor should be on   */
#define FD_EMPTY        (1<<3)  /* no media             */
#define FD_NEWDISK      (1<<4)  /* media changed        */
#define FD_ISADMA       (1<<5)  /* isa dma started      */
        int     track;          /* where we think the head is */
#define FD_NO_TRACK      -2
        int     options;        /* FDOPT_* */
        struct  callout toffhandle;
        struct g_geom *fd_geom;
        struct g_provider *fd_provider;
        device_t dev;
        struct bio_queue_head fd_bq;
        bool    gone;
};

#define FD_NOT_VALID -2

static driver_intr_t fdc_intr;
static driver_filter_t fdc_intr_fast;
static void fdc_reset(struct fdc_data *);
static int fd_probe_disk(struct fd_data *, int *);

static SYSCTL_NODE(_debug, OID_AUTO, fdc, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
    "fdc driver");

static int fifo_threshold = 8;
SYSCTL_INT(_debug_fdc, OID_AUTO, fifo, CTLFLAG_RW, &fifo_threshold, 0,
        "FIFO threshold setting");

static int debugflags = 0;
SYSCTL_INT(_debug_fdc, OID_AUTO, debugflags, CTLFLAG_RW, &debugflags, 0,
        "Debug flags");

static int retries = 10;
SYSCTL_INT(_debug_fdc, OID_AUTO, retries, CTLFLAG_RW, &retries, 0,
        "Number of retries to attempt");

static int spec1 = NE7_SPEC_1(6, 240);
SYSCTL_INT(_debug_fdc, OID_AUTO, spec1, CTLFLAG_RW, &spec1, 0,
        "Specification byte one (step-rate + head unload)");

static int spec2 = NE7_SPEC_2(16, 0);
SYSCTL_INT(_debug_fdc, OID_AUTO, spec2, CTLFLAG_RW, &spec2, 0,
        "Specification byte two (head load time + no-dma)");

static int settle;
SYSCTL_INT(_debug_fdc, OID_AUTO, settle, CTLFLAG_RW, &settle, 0,
        "Head settling time in sec/hz");

static void
fdprinttype(struct fd_type *ft)
{

        printf("(%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,0x%x)",
            ft->sectrac, ft->secsize, ft->datalen, ft->gap, ft->tracks,
            ft->size, ft->trans, ft->heads, ft->f_gap, ft->f_inter,
            ft->offset_side2, ft->flags);
}

static void
fdsettype(struct fd_data *fd, struct fd_type *ft)
{
        fd->ft = ft;
        ft->size = ft->sectrac * ft->heads * ft->tracks;
        fd->sectorsize = 128 << fd->ft->secsize;
}

/*
 * Bus space handling (access to low-level IO).
 */
static inline void
fdregwr(struct fdc_data *fdc, int reg, uint8_t v)
{

        bus_space_write_1(fdc->iot, fdc->ioh[reg], fdc->ioff[reg], v);
}

static inline uint8_t
fdregrd(struct fdc_data *fdc, int reg)
{

        return bus_space_read_1(fdc->iot, fdc->ioh[reg], fdc->ioff[reg]);
}

static void
fdctl_wr(struct fdc_data *fdc, u_int8_t v)
{

        fdregwr(fdc, FDCTL, v);
}

static void
fdout_wr(struct fdc_data *fdc, u_int8_t v)
{

        fdregwr(fdc, FDOUT, v);
}

static u_int8_t
fdsts_rd(struct fdc_data *fdc)
{

        return fdregrd(fdc, FDSTS);
}

static void
fddsr_wr(struct fdc_data *fdc, u_int8_t v)
{

        fdregwr(fdc, FDDSR, v);
}

static void
fddata_wr(struct fdc_data *fdc, u_int8_t v)
{

        fdregwr(fdc, FDDATA, v);
}

static u_int8_t
fddata_rd(struct fdc_data *fdc)
{

        return fdregrd(fdc, FDDATA);
}

static u_int8_t
fdin_rd(struct fdc_data *fdc)
{

        return fdregrd(fdc, FDCTL);
}

/*
 * Magic pseudo-DMA initialization for YE FDC. Sets count and
 * direction.
 */
static void
fdbcdr_wr(struct fdc_data *fdc, int iswrite, uint16_t count)
{
        fdregwr(fdc, FDBCDR, (count - 1) & 0xff);
        fdregwr(fdc, FDBCDR + 1,
            (iswrite ? 0x80 : 0) | (((count - 1) >> 8) & 0x7f));
}

static int
fdc_err(struct fdc_data *fdc, const char *s)
{
        fdc->fdc_errs++;
        if (s) {
                if (fdc->fdc_errs < FDC_ERRMAX)
                        device_printf(fdc->fdc_dev, "%s", s);
                else if (fdc->fdc_errs == FDC_ERRMAX)
                        device_printf(fdc->fdc_dev, "too many errors, not "
                                                    "logging any more\n");
        }

        return (1);
}

/*
 * FDC IO functions, take care of the main status register, timeout
 * in case the desired status bits are never set.
 *
 * These PIO loops initially start out with short delays between
 * each iteration in the expectation that the required condition
 * is usually met quickly, so it can be handled immediately.
 */
static int
fdc_in(struct fdc_data *fdc, int *ptr)
{
        int i, j, step;

        step = 1;
        for (j = 0; j < FDSTS_TIMEOUT; j += step) {
                i = fdsts_rd(fdc) & (NE7_DIO | NE7_RQM);
                if (i == (NE7_DIO|NE7_RQM)) {
                        i = fddata_rd(fdc);
                        if (ptr)
                                *ptr = i;
                        return (0);
                }
                if (i == NE7_RQM)
                        return (fdc_err(fdc, "ready for output in input\n"));
                step += step;
                DELAY(step);
        }
        return (fdc_err(fdc, bootverbose? "input ready timeout\n": 0));
}

static int
fdc_out(struct fdc_data *fdc, int x)
{
        int i, j, step;

        step = 1;
        for (j = 0; j < FDSTS_TIMEOUT; j += step) {
                i = fdsts_rd(fdc) & (NE7_DIO | NE7_RQM);
                if (i == NE7_RQM) {
                        fddata_wr(fdc, x);
                        return (0);
                }
                if (i == (NE7_DIO|NE7_RQM))
                        return (fdc_err(fdc, "ready for input in output\n"));
                step += step;
                DELAY(step);
        }
        return (fdc_err(fdc, bootverbose? "output ready timeout\n": 0));
}

/*
 * fdc_cmd: Send a command to the chip.
 * Takes a varargs with this structure:
 *      # of output bytes
 *      output bytes as int [...]
 *      # of input bytes
 *      input bytes as int* [...]
 */
static int
fdc_cmd(struct fdc_data *fdc, int n_out, ...)
{
        u_char cmd = 0;
        int n_in;
        int n, i;
        va_list ap;

        va_start(ap, n_out);
        for (n = 0; n < n_out; n++) {
                i = va_arg(ap, int);
                if (n == 0)
                        cmd = i;
                if (fdc_out(fdc, i) < 0) {
                        char msg[50];
                        snprintf(msg, sizeof(msg),
                                "cmd %x failed at out byte %d of %d\n",
                                cmd, n + 1, n_out);
                        fdc->flags |= FDC_NEEDS_RESET;
                        va_end(ap);
                        return fdc_err(fdc, msg);
                }
        }
        n_in = va_arg(ap, int);
        for (n = 0; n < n_in; n++) {
                int *ptr = va_arg(ap, int *);
                if (fdc_in(fdc, ptr) != 0) {
                        char msg[50];
                        snprintf(msg, sizeof(msg),
                                "cmd %02x failed at in byte %d of %d\n",
                                cmd, n + 1, n_in);
                        fdc->flags |= FDC_NEEDS_RESET;
                        va_end(ap);
                        return fdc_err(fdc, msg);
                }
        }
        va_end(ap);
        return (0);
}

static void
fdc_reset(struct fdc_data *fdc)
{
        int i, r[10];

        if (fdc->fdct == FDC_ENHANCED) {
                /* Try a software reset, default precomp, and 500 kb/s */
                fddsr_wr(fdc, I8207X_DSR_SR);
        } else {
                /* Try a hardware reset, keep motor on */
                fdout_wr(fdc, fdc->fdout & ~(FDO_FRST|FDO_FDMAEN));
                DELAY(100);
                /* enable FDC, but defer interrupts a moment */
                fdout_wr(fdc, fdc->fdout & ~FDO_FDMAEN);
        }
        DELAY(100);
        fdout_wr(fdc, fdc->fdout);

        /* XXX after a reset, silently believe the FDC will accept commands */
        if (fdc_cmd(fdc, 3, NE7CMD_SPECIFY, spec1, spec2, 0))
                device_printf(fdc->fdc_dev, " SPECIFY failed in reset\n");

        if (fdc->fdct == FDC_ENHANCED) {
                if (fdc_cmd(fdc, 4,
                    I8207X_CONFIG,
                    0,
                    /* 0x40 | */                /* Enable Implied Seek -
                                                 * breaks 2step! */
                    0x10 |                      /* Polling disabled */
                    (fifo_threshold - 1),       /* Fifo threshold */
                    0x00,                       /* Precomp track */
                    0))
                        device_printf(fdc->fdc_dev,
                            " CONFIGURE failed in reset\n");
                if (debugflags & 1) {
                        if (fdc_cmd(fdc, 1,
                            I8207X_DUMPREG,
                            10, &r[0], &r[1], &r[2], &r[3], &r[4],
                            &r[5], &r[6], &r[7], &r[8], &r[9]))
                                device_printf(fdc->fdc_dev,
                                    " DUMPREG failed in reset\n");
                        for (i = 0; i < 10; i++)
                                printf(" %02x", r[i]);
                        printf("\n");
                }
        }
}

static int
fdc_sense_drive(struct fdc_data *fdc, int *st3p)
{
        int st3;

        if (fdc_cmd(fdc, 2, NE7CMD_SENSED, fdc->fd->fdsu, 1, &st3))
                return (fdc_err(fdc, "Sense Drive Status failed\n"));
        if (st3p)
                *st3p = st3;
        return (0);
}

static int
fdc_sense_int(struct fdc_data *fdc, int *st0p, int *cylp)
{
        int cyl, st0, ret;

        ret = fdc_cmd(fdc, 1, NE7CMD_SENSEI, 1, &st0);
        if (ret) {
                (void)fdc_err(fdc, "sense intr err reading stat reg 0\n");
                return (ret);
        }

        if (st0p)
                *st0p = st0;

        if ((st0 & NE7_ST0_IC) == NE7_ST0_IC_IV) {
                /*
                 * There doesn't seem to have been an interrupt.
                 */
                return (FD_NOT_VALID);
        }

        if (fdc_in(fdc, &cyl) != 0)
                return fdc_err(fdc, "can't get cyl num\n");

        if (cylp)
                *cylp = cyl;

        return (0);
}

static int
fdc_read_status(struct fdc_data *fdc)
{
        int i, ret, status;

        for (i = ret = 0; i < 7; i++) {
                ret = fdc_in(fdc, &status);
                fdc->status[i] = status;
                if (ret != 0)
                        break;
        }

        if (ret == 0)
                fdc->flags |= FDC_STAT_VALID;
        else
                fdc->flags &= ~FDC_STAT_VALID;

        return ret;
}

/*
 * Select this drive
 */
static void
fd_select(struct fd_data *fd)
{
        struct fdc_data *fdc;

        /* XXX: lock controller */
        fdc = fd->fdc;
        fdc->fdout &= ~FDO_FDSEL;
        fdc->fdout |= FDO_FDMAEN | FDO_FRST | fd->fdsu;
        fdout_wr(fdc, fdc->fdout);
}

static void
fd_turnon(void *arg)
{
        struct fd_data *fd;
        struct bio *bp;
        int once;

        fd = arg;
        mtx_assert(&fd->fdc->fdc_mtx, MA_OWNED);
        fd->flags &= ~FD_MOTORWAIT;
        fd->flags |= FD_MOTOR;
        once = 0;
        for (;;) {
                bp = bioq_takefirst(&fd->fd_bq);
                if (bp == NULL)
                        break;
                bioq_disksort(&fd->fdc->head, bp);
                once = 1;
        }
        if (once)
                wakeup(&fd->fdc->head);
}

static void
fd_motor(struct fd_data *fd, int turnon)
{
        struct fdc_data *fdc;

        fdc = fd->fdc;
/*
        mtx_assert(&fdc->fdc_mtx, MA_OWNED);
*/
        if (turnon) {
                fd->flags |= FD_MOTORWAIT;
                fdc->fdout |= (FDO_MOEN0 << fd->fdsu);
                callout_reset(&fd->toffhandle, hz, fd_turnon, fd);
        } else {
                callout_stop(&fd->toffhandle);
                fd->flags &= ~(FD_MOTOR|FD_MOTORWAIT);
                fdc->fdout &= ~(FDO_MOEN0 << fd->fdsu);
        }
        fdout_wr(fdc, fdc->fdout);
}

static void
fd_turnoff(void *xfd)
{
        struct fd_data *fd = xfd;

        mtx_assert(&fd->fdc->fdc_mtx, MA_OWNED);
        fd_motor(fd, 0);
}

/*
 * fdc_intr - wake up the worker thread.
 */

static void
fdc_intr(void *arg)
{

        wakeup(arg);
}

static int
fdc_intr_fast(void *arg)
{

        wakeup(arg);
        return(FILTER_HANDLED);
}

/*
 * fdc_pio(): perform programmed IO read/write for YE PCMCIA floppy.
 */
static void
fdc_pio(struct fdc_data *fdc)
{
        u_char *cptr;
        struct bio *bp;
        u_int count;

        bp = fdc->bp;
        cptr = fdc->fd->fd_ioptr;
        count = fdc->fd->fd_iosize;

        if (bp->bio_cmd == BIO_READ) {
                fdbcdr_wr(fdc, 0, count);
                bus_space_read_multi_1(fdc->iot, fdc->ioh[FD_YE_DATAPORT],
                    fdc->ioff[FD_YE_DATAPORT], cptr, count);
        } else {
                bus_space_write_multi_1(fdc->iot, fdc->ioh[FD_YE_DATAPORT],
                    fdc->ioff[FD_YE_DATAPORT], cptr, count);
                fdbcdr_wr(fdc, 0, count);       /* needed? */
        }
}

static int
fdc_biodone(struct fdc_data *fdc, int error)
{
        struct fd_data *fd;
        struct bio *bp;

        fd = fdc->fd;
        bp = fdc->bp;

        mtx_lock(&fdc->fdc_mtx);
        if (--fd->fd_iocount == 0)
                callout_reset(&fd->toffhandle, 4 * hz, fd_turnoff, fd);
        fdc->bp = NULL;
        fdc->fd = NULL;
        mtx_unlock(&fdc->fdc_mtx);
        if (bp->bio_to != NULL) {
                if ((debugflags & 2) && fd->fdc->retry > 0)
                        printf("retries: %d\n", fd->fdc->retry);
                g_io_deliver(bp, error);
                return (0);
        }
        bp->bio_error = error;
        bp->bio_flags |= BIO_DONE;
        wakeup(bp);
        return (0);
}

static int retry_line;

static int
fdc_worker(struct fdc_data *fdc)
{
        struct fd_data *fd;
        struct bio *bp;
        int i, nsect;
        int st0, st3, cyl, mfm, steptrac, cylinder, descyl, sec;
        int head;
        int override_error;
        static int need_recal;
        struct fdc_readid *idp;
        struct fd_formb *finfo;

        override_error = 0;

        /* Have we exhausted our retries ? */
        bp = fdc->bp;
        fd = fdc->fd;
        if (bp != NULL &&
                (fdc->retry >= retries || (fd->options & FDOPT_NORETRY))) {
                if ((debugflags & 4))
                        printf("Too many retries (EIO)\n");
                if (fdc->flags & FDC_NEEDS_RESET) {
                        mtx_lock(&fdc->fdc_mtx);
                        fd->flags |= FD_EMPTY;
                        mtx_unlock(&fdc->fdc_mtx);
                }
                return (fdc_biodone(fdc, EIO));
        }

        /* Disable ISADMA if we bailed while it was active */
        if (fd != NULL && (fd->flags & FD_ISADMA)) {
                isa_dmadone(
                    bp->bio_cmd == BIO_READ ? ISADMA_READ : ISADMA_WRITE,
                    fd->fd_ioptr, fd->fd_iosize, fdc->dmachan);
                mtx_lock(&fdc->fdc_mtx);
                fd->flags &= ~FD_ISADMA;
                mtx_unlock(&fdc->fdc_mtx);
        }

        /* Unwedge the controller ? */
        if (fdc->flags & FDC_NEEDS_RESET) {
                fdc->flags &= ~FDC_NEEDS_RESET;
                fdc_reset(fdc);
                if (cold)
                        DELAY(1000000);
                else
                        tsleep(fdc, PRIBIO, "fdcrst", hz);
                /* Discard results */
                for (i = 0; i < 4; i++)
                        fdc_sense_int(fdc, &st0, &cyl);
                /* All drives must recal */
                need_recal = 0xf;
        }

        /* Pick up a request, if need be wait for it */
        if (fdc->bp == NULL) {
                mtx_lock(&fdc->fdc_mtx);
                do {
                        fdc->bp = bioq_takefirst(&fdc->head);
                        if (fdc->bp == NULL)
                                msleep(&fdc->head, &fdc->fdc_mtx,
                                    PRIBIO, "-", 0);
                } while (fdc->bp == NULL &&
                    (fdc->flags & FDC_KTHREAD_EXIT) == 0);
                mtx_unlock(&fdc->fdc_mtx);

                if (fdc->bp == NULL)
                        /*
                         * Nothing to do, worker thread has been
                         * requested to stop.
                         */
                        return (0);

                bp = fdc->bp;
                fd = fdc->fd = bp->bio_driver1;
                fdc->retry = 0;
                fd->fd_ioptr = bp->bio_data;
                if (bp->bio_cmd == BIO_FMT) {
                        i = offsetof(struct fd_formb, fd_formb_cylno(0));
                        fd->fd_ioptr += i;
                        fd->fd_iosize = bp->bio_length - i;
                }
        }

        /* Select drive, setup params */
        fd_select(fd);
        if (fdc->fdct == FDC_ENHANCED)
                fddsr_wr(fdc, fd->ft->trans);
        else
                fdctl_wr(fdc, fd->ft->trans);

        if (bp->bio_cmd == BIO_PROBE) {
                if ((!(device_get_flags(fd->dev) & FD_NO_CHLINE) &&
                    !(fdin_rd(fdc) & FDI_DCHG) &&
                    !(fd->flags & FD_EMPTY)) ||
                    fd_probe_disk(fd, &need_recal) == 0)
                        return (fdc_biodone(fdc, 0));
                return (1);
        }

        /*
         * If we are dead just flush the requests
         */
        if (fd->flags & FD_EMPTY)
                return (fdc_biodone(fdc, ENXIO));

        /* Check if we lost our media */
        if (fdin_rd(fdc) & FDI_DCHG) {
                if (debugflags & 0x40)
                        printf("Lost disk\n");
                mtx_lock(&fdc->fdc_mtx);
                fd->flags |= FD_EMPTY;
                fd->flags |= FD_NEWDISK;
                mtx_unlock(&fdc->fdc_mtx);
                g_topology_lock();
                g_orphan_provider(fd->fd_provider, ENXIO);
                fd->fd_provider->flags |= G_PF_WITHER;
                fd->fd_provider =
                    g_new_providerf(fd->fd_geom, "%s", fd->fd_geom->name);
                g_error_provider(fd->fd_provider, 0);
                g_topology_unlock();
                return (fdc_biodone(fdc, ENXIO));
        }

        /* Check if the floppy is write-protected */
        if (bp->bio_cmd == BIO_FMT || bp->bio_cmd == BIO_WRITE) {
                retry_line = __LINE__;
                if(fdc_sense_drive(fdc, &st3) != 0)
                        return (1);
                if(st3 & NE7_ST3_WP)
                        return (fdc_biodone(fdc, EROFS));
        }

        mfm = (fd->ft->flags & FL_MFM)? NE7CMD_MFM: 0;
        steptrac = (fd->ft->flags & FL_2STEP)? 2: 1;
        i = fd->ft->sectrac * fd->ft->heads;
        cylinder = bp->bio_pblkno / i;
        descyl = cylinder * steptrac;
        sec = bp->bio_pblkno % i;
        nsect = i - sec;
        head = sec / fd->ft->sectrac;
        sec = sec % fd->ft->sectrac + 1;

        /* If everything is going swimmingly, use multisector xfer */
        if (fdc->retry == 0 &&
            (bp->bio_cmd == BIO_READ || bp->bio_cmd == BIO_WRITE)) {
                fd->fd_iosize = imin(nsect * fd->sectorsize, bp->bio_resid);
                nsect = fd->fd_iosize / fd->sectorsize;
        } else if (bp->bio_cmd == BIO_READ || bp->bio_cmd == BIO_WRITE) {
                fd->fd_iosize = fd->sectorsize;
                nsect = 1;
        }

        /* Do RECAL if we need to or are going to track zero anyway */
        if ((need_recal & (1 << fd->fdsu)) ||
            (cylinder == 0 && fd->track != 0) ||
            fdc->retry > 2) {
                retry_line = __LINE__;
                if (fdc_cmd(fdc, 2, NE7CMD_RECAL, fd->fdsu, 0))
                        return (1);
                tsleep(fdc, PRIBIO, "fdrecal", hz);
                retry_line = __LINE__;
                if (fdc_sense_int(fdc, &st0, &cyl) == FD_NOT_VALID)
                        return (1); /* XXX */
                retry_line = __LINE__;
                if ((st0 & 0xc0) || cyl != 0)
                        return (1);
                need_recal &= ~(1 << fd->fdsu);
                fd->track = 0;
                /* let the heads settle */
                if (settle)
                        tsleep(fdc->fd, PRIBIO, "fdhdstl", settle);
        }

        /*
         * SEEK to where we want to be
         */
        if (cylinder != fd->track) {
                retry_line = __LINE__;
                if (fdc_cmd(fdc, 3, NE7CMD_SEEK, fd->fdsu, descyl, 0))
                        return (1);
                tsleep(fdc, PRIBIO, "fdseek", hz);
                retry_line = __LINE__;
                if (fdc_sense_int(fdc, &st0, &cyl) == FD_NOT_VALID)
                        return (1); /* XXX */
                retry_line = __LINE__;
                if ((st0 & 0xc0) || cyl != descyl) {
                        need_recal |= (1 << fd->fdsu);
                        return (1);
                }
                /* let the heads settle */
                if (settle)
                        tsleep(fdc->fd, PRIBIO, "fdhdstl", settle);
        }
        fd->track = cylinder;

        if (debugflags & 8)
                printf("op %x bn %ju siz %u ptr %p retry %d\n",
                    bp->bio_cmd, bp->bio_pblkno, fd->fd_iosize,
                    fd->fd_ioptr, fdc->retry);

        /* Setup ISADMA if we need it and have it */
        if ((bp->bio_cmd == BIO_READ ||
                bp->bio_cmd == BIO_WRITE ||
                bp->bio_cmd == BIO_FMT)
             && !(fdc->flags & FDC_NODMA)) {
                isa_dmastart(
                    bp->bio_cmd == BIO_READ ? ISADMA_READ : ISADMA_WRITE,
                    fd->fd_ioptr, fd->fd_iosize, fdc->dmachan);
                mtx_lock(&fdc->fdc_mtx);
                fd->flags |= FD_ISADMA;
                mtx_unlock(&fdc->fdc_mtx);
        }

        /* Do PIO if we have to */
        if (fdc->flags & FDC_NODMA) {
                if (bp->bio_cmd == BIO_READ ||
                    bp->bio_cmd == BIO_WRITE ||
                    bp->bio_cmd == BIO_FMT)
                        fdbcdr_wr(fdc, 1, fd->fd_iosize);
                if (bp->bio_cmd == BIO_WRITE ||
                    bp->bio_cmd == BIO_FMT)
                        fdc_pio(fdc);
        }

        switch(bp->bio_cmd) {
        case BIO_FMT:
                /* formatting */
                finfo = (struct fd_formb *)bp->bio_data;
                retry_line = __LINE__;
                if (fdc_cmd(fdc, 6,
                    NE7CMD_FORMAT | mfm,
                    head << 2 | fd->fdsu,
                    finfo->fd_formb_secshift,
                    finfo->fd_formb_nsecs,
                    finfo->fd_formb_gaplen,
                    finfo->fd_formb_fillbyte, 0))
                        return (1);
                break;
        case BIO_RDID:
                retry_line = __LINE__;
                if (fdc_cmd(fdc, 2,
                    NE7CMD_READID | mfm,
                    head << 2 | fd->fdsu, 0))
                        return (1);
                break;
        case BIO_READ:
                retry_line = __LINE__;
                if (fdc_cmd(fdc, 9,
                    NE7CMD_READ | NE7CMD_SK | mfm | NE7CMD_MT,
                    head << 2 | fd->fdsu,       /* head & unit */
                    fd->track,                  /* track */
                    head,                       /* head */
                    sec,                        /* sector + 1 */
                    fd->ft->secsize,            /* sector size */
                    fd->ft->sectrac,            /* sectors/track */
                    fd->ft->gap,                /* gap size */
                    fd->ft->datalen,            /* data length */
                    0))
                        return (1);
                break;
        case BIO_WRITE:
                retry_line = __LINE__;
                if (fdc_cmd(fdc, 9,
                    NE7CMD_WRITE | mfm | NE7CMD_MT,
                    head << 2 | fd->fdsu,       /* head & unit */
                    fd->track,                  /* track */
                    head,                       /* head */
                    sec,                        /* sector + 1 */
                    fd->ft->secsize,            /* sector size */
                    fd->ft->sectrac,            /* sectors/track */
                    fd->ft->gap,                /* gap size */
                    fd->ft->datalen,            /* data length */
                    0))
                        return (1);
                break;
        default:
                KASSERT(0 == 1, ("Wrong bio_cmd %x\n", bp->bio_cmd));
        }

        /* Wait for interrupt */
        i = tsleep(fdc, PRIBIO, "fddata", hz);

        /* PIO if the read looks good */
        if (i == 0 && (fdc->flags & FDC_NODMA) && (bp->bio_cmd == BIO_READ))
                fdc_pio(fdc);

        /* Finish DMA */
        if (fd->flags & FD_ISADMA) {
                isa_dmadone(
                    bp->bio_cmd == BIO_READ ? ISADMA_READ : ISADMA_WRITE,
                    fd->fd_ioptr, fd->fd_iosize, fdc->dmachan);
                mtx_lock(&fdc->fdc_mtx);
                fd->flags &= ~FD_ISADMA;
                mtx_unlock(&fdc->fdc_mtx);
        }

        if (i != 0) {
                /*
                 * Timeout.
                 *
                 * Due to IBM's brain-dead design, the FDC has a faked ready
                 * signal, hardwired to ready == true. Thus, any command
                 * issued if there's no diskette in the drive will _never_
                 * complete, and must be aborted by resetting the FDC.
                 * Many thanks, Big Blue!
                 */
                retry_line = __LINE__;
                fdc->flags |= FDC_NEEDS_RESET;
                return (1);
        }

        retry_line = __LINE__;
        if (fdc_read_status(fdc))
                return (1);

        if (debugflags & 0x10)
                printf("  -> %x %x %x %x\n",
                    fdc->status[0], fdc->status[1],
                    fdc->status[2], fdc->status[3]);

        st0 = fdc->status[0] & NE7_ST0_IC;
        if (st0 != 0) {
                retry_line = __LINE__;
                if (st0 == NE7_ST0_IC_AT && fdc->status[1] & NE7_ST1_OR) {
                        /*
                         * DMA overrun. Someone hogged the bus and
                         * didn't release it in time for the next
                         * FDC transfer.
                         */
                        return (1);
                }
                retry_line = __LINE__;
                if(st0 == NE7_ST0_IC_IV) {
                        fdc->flags |= FDC_NEEDS_RESET;
                        return (1);
                }
                retry_line = __LINE__;
                if(st0 == NE7_ST0_IC_AT && fdc->status[2] & NE7_ST2_WC) {
                        need_recal |= (1 << fd->fdsu);
                        return (1);
                }
                if (debugflags & 0x20) {
                        printf("status %02x %02x %02x %02x %02x %02x\n",
                            fdc->status[0], fdc->status[1], fdc->status[2],
                            fdc->status[3], fdc->status[4], fdc->status[5]);
                }
                retry_line = __LINE__;
                if (fd->options & FDOPT_NOERROR)
                        override_error = 1;
                else
                        return (1);
        }
        /* All OK */
        switch(bp->bio_cmd) {
        case BIO_RDID:
                /* copy out ID field contents */
                idp = (struct fdc_readid *)bp->bio_data;
                idp->cyl = fdc->status[3];
                idp->head = fdc->status[4];
                idp->sec = fdc->status[5];
                idp->secshift = fdc->status[6];
                if (debugflags & 0x40)
                        printf("c %d h %d s %d z %d\n",
                            idp->cyl, idp->head, idp->sec, idp->secshift);
                break;
        case BIO_READ:
        case BIO_WRITE:
                bp->bio_pblkno += nsect;
                bp->bio_resid -= fd->fd_iosize;
                bp->bio_completed += fd->fd_iosize;
                fd->fd_ioptr += fd->fd_iosize;
                if (override_error) {
                        if ((debugflags & 4))
                                printf("FDOPT_NOERROR: returning bad data\n");
                } else {
                        /* Since we managed to get something done,
                         * reset the retry */
                        fdc->retry = 0;
                        if (bp->bio_resid > 0)
                                return (0);
                }
                break;
        case BIO_FMT:
                break;
        }
        return (fdc_biodone(fdc, 0));
}

static void
fdc_thread(void *arg)
{
        struct fdc_data *fdc;

        fdc = arg;
        int i;

        mtx_lock(&fdc->fdc_mtx);
        fdc->flags |= FDC_KTHREAD_ALIVE;
        while ((fdc->flags & FDC_KTHREAD_EXIT) == 0) {
                mtx_unlock(&fdc->fdc_mtx);
                i = fdc_worker(fdc);
                if (i && debugflags & 0x20) {
                        if (fdc->bp != NULL)
                                g_print_bio("", fdc->bp, "");
                        printf("Retry line %d\n", retry_line);
                }
                fdc->retry += i;
                mtx_lock(&fdc->fdc_mtx);
        }
        fdc->flags &= ~(FDC_KTHREAD_EXIT | FDC_KTHREAD_ALIVE);
        mtx_unlock(&fdc->fdc_mtx);

        kproc_exit(0);
}

/*
 * Enqueue a request.
 */
static void
fd_enqueue(struct fd_data *fd, struct bio *bp)
{
        struct fdc_data *fdc;

        fdc = fd->fdc;
        mtx_lock(&fdc->fdc_mtx);
        /* If we go from idle, cancel motor turnoff */
        if (fd->fd_iocount++ == 0)
                callout_stop(&fd->toffhandle);
        if (fd->flags & FD_MOTOR) {
                /* The motor is on, send it directly to the controller */
                bioq_disksort(&fdc->head, bp);
                wakeup(&fdc->head);
        } else {
                /* Queue it on the drive until the motor has started */
                bioq_insert_tail(&fd->fd_bq, bp);
                if (!(fd->flags & FD_MOTORWAIT))
                        fd_motor(fd, 1);
        }
        mtx_unlock(&fdc->fdc_mtx);
}

/*
 * Try to find out if we have a disk in the drive.
 */
static int
fd_probe_disk(struct fd_data *fd, int *recal)
{
        struct fdc_data *fdc;
        int st0, st3, cyl;
        int oopts, ret;

        fdc = fd->fdc;
        oopts = fd->options;
        fd->options |= FDOPT_NOERRLOG | FDOPT_NORETRY;
        ret = 1;

        /*
         * First recal, then seek to cyl#1, this clears the old condition on
         * the disk change line so we can examine it for current status.
         */
        if (debugflags & 0x40)
                printf("New disk in probe\n");
        mtx_lock(&fdc->fdc_mtx);
        fd->flags |= FD_NEWDISK;
        mtx_unlock(&fdc->fdc_mtx);
        if (fdc_cmd(fdc, 2, NE7CMD_RECAL, fd->fdsu, 0))
                goto done;
        tsleep(fdc, PRIBIO, "fdrecal", hz);
        if (fdc_sense_int(fdc, &st0, &cyl) == FD_NOT_VALID)
                goto done;      /* XXX */
        if ((st0 & 0xc0) || cyl != 0)
                goto done;

        /* Seek to track 1 */
        if (fdc_cmd(fdc, 3, NE7CMD_SEEK, fd->fdsu, 1, 0))
                goto done;
        tsleep(fdc, PRIBIO, "fdseek", hz);
        if (fdc_sense_int(fdc, &st0, &cyl) == FD_NOT_VALID)
                goto done;      /* XXX */
        *recal |= (1 << fd->fdsu);
        if (fdin_rd(fdc) & FDI_DCHG) {
                if (debugflags & 0x40)
                        printf("Empty in probe\n");
                mtx_lock(&fdc->fdc_mtx);
                fd->flags |= FD_EMPTY;
                mtx_unlock(&fdc->fdc_mtx);
        } else {
                if (fdc_sense_drive(fdc, &st3) != 0)
                        goto done;
                if (debugflags & 0x40)
                        printf("Got disk in probe\n");
                mtx_lock(&fdc->fdc_mtx);
                fd->flags &= ~FD_EMPTY;
                if (st3 & NE7_ST3_WP)
                        fd->flags |= FD_WP;
                else
                        fd->flags &= ~FD_WP;
                mtx_unlock(&fdc->fdc_mtx);
        }
        ret = 0;

done:
        fd->options = oopts;
        return (ret);
}

static int
fdmisccmd(struct fd_data *fd, u_int cmd, void *data)
{
        struct bio *bp;
        struct fd_formb *finfo;
        struct fdc_readid *idfield;
        int error;

        bp = malloc(sizeof(struct bio), M_TEMP, M_WAITOK | M_ZERO);

        /*
         * Set up a bio request for fdstrategy().  bio_offset is faked
         * so that fdstrategy() will seek to the requested
         * cylinder, and use the desired head.
         */
        bp->bio_cmd = cmd;
        if (cmd == BIO_FMT) {
                finfo = (struct fd_formb *)data;
                bp->bio_pblkno =
                    (finfo->cyl * fd->ft->heads + finfo->head) *
                    fd->ft->sectrac;
                bp->bio_length = sizeof *finfo;
        } else if (cmd == BIO_RDID) {
                idfield = (struct fdc_readid *)data;
                bp->bio_pblkno =
                    (idfield->cyl * fd->ft->heads + idfield->head) *
                    fd->ft->sectrac;
                bp->bio_length = sizeof(struct fdc_readid);
        } else if (cmd == BIO_PROBE) {
                /* nothing */
        } else
                panic("wrong cmd in fdmisccmd()");
        bp->bio_offset = bp->bio_pblkno * fd->sectorsize;
        bp->bio_data = data;
        bp->bio_driver1 = fd;
        bp->bio_flags = 0;

        fd_enqueue(fd, bp);

        do {
                tsleep(bp, PRIBIO, "fdwait", hz);
        } while (!(bp->bio_flags & BIO_DONE));
        error = bp->bio_error;

        free(bp, M_TEMP);
        return (error);
}

/*
 * Try figuring out the density of the media present in our device.
 */
static int
fdautoselect(struct fd_data *fd)
{
        struct fd_type *fdtp;
        struct fdc_readid id;
        int oopts, rv;

        if (!(fd->ft->flags & FL_AUTO))
                return (0);

        fdtp = fd_native_types[fd->type];
        fdsettype(fd, fdtp);
        if (!(fd->ft->flags & FL_AUTO))
                return (0);

        /*
         * Try reading sector ID fields, first at cylinder 0, head 0,
         * then at cylinder 2, head N.  We don't probe cylinder 1,
         * since for 5.25in DD media in a HD drive, there are no data
         * to read (2 step pulses per media cylinder required).  For
         * two-sided media, the second probe always goes to head 1, so
         * we can tell them apart from single-sided media.  As a
         * side-effect this means that single-sided media should be
         * mentioned in the search list after two-sided media of an
         * otherwise identical density.  Media with a different number
         * of sectors per track but otherwise identical parameters
         * cannot be distinguished at all.
         *
         * If we successfully read an ID field on both cylinders where
         * the recorded values match our expectation, we are done.
         * Otherwise, we try the next density entry from the table.
         *
         * Stepping to cylinder 2 has the side-effect of clearing the
         * unit attention bit.
         */
        oopts = fd->options;
        fd->options |= FDOPT_NOERRLOG | FDOPT_NORETRY;
        for (; fdtp->heads; fdtp++) {
                fdsettype(fd, fdtp);

                id.cyl = id.head = 0;
                rv = fdmisccmd(fd, BIO_RDID, &id);
                if (rv != 0)
                        continue;
                if (id.cyl != 0 || id.head != 0 || id.secshift != fdtp->secsize)
                        continue;
                id.cyl = 2;
                id.head = fd->ft->heads - 1;
                rv = fdmisccmd(fd, BIO_RDID, &id);
                if (id.cyl != 2 || id.head != fdtp->heads - 1 ||
                    id.secshift != fdtp->secsize)
                        continue;
                if (rv == 0)
                        break;
        }

        fd->options = oopts;
        if (fdtp->heads == 0) {
                if (debugflags & 0x40)
                        device_printf(fd->dev, "autoselection failed\n");
                fdsettype(fd, fd_native_types[fd->type]);
                return (-1);
        } else {
                if (debugflags & 0x40) {
                        device_printf(fd->dev,
                            "autoselected %d KB medium\n",
                            fd->ft->size / 2);
                        fdprinttype(fd->ft);
                }
                return (0);
        }
}

/*
 * GEOM class implementation
 */

static g_access_t       fd_access;
static g_start_t        fd_start;
static g_ioctl_t        fd_ioctl;
static g_provgone_t     fd_providergone;

struct g_class g_fd_class = {
        .name =         "FD",
        .version =      G_VERSION,
        .start =        fd_start,
        .access =       fd_access,
        .ioctl =        fd_ioctl,
        .providergone = fd_providergone,
};

static int
fd_access(struct g_provider *pp, int r, int w, int e)
{
        struct fd_data *fd;
        struct fdc_data *fdc;
        int ar, aw, ae;

        fd = pp->geom->softc;
        fdc = fd->fdc;

        /*
         * If our provider is withering, we can only get negative requests
         * and we don't want to even see them
         */
        if (pp->flags & G_PF_WITHER)
                return (0);

        ar = r + pp->acr;
        aw = w + pp->acw;
        ae = e + pp->ace;

        if (ar == 0 && aw == 0 && ae == 0) {
                fd->options &= ~(FDOPT_NORETRY | FDOPT_NOERRLOG | FDOPT_NOERROR);
                return (0);
        }

        if (pp->acr == 0 && pp->acw == 0 && pp->ace == 0) {
                if (fdmisccmd(fd, BIO_PROBE, NULL))
                        return (ENXIO);
                if (fd->flags & FD_EMPTY)
                        return (ENXIO);
                if (fd->flags & FD_NEWDISK) {
                        if (fdautoselect(fd) != 0 &&
                            (device_get_flags(fd->dev) & FD_NO_CHLINE)) {
                                mtx_lock(&fdc->fdc_mtx);
                                fd->flags |= FD_EMPTY;
                                mtx_unlock(&fdc->fdc_mtx);
                                return (ENXIO);
                        }
                        mtx_lock(&fdc->fdc_mtx);
                        fd->flags &= ~FD_NEWDISK;
                        mtx_unlock(&fdc->fdc_mtx);
                }
        }

        if (w > 0 && (fd->flags & FD_WP)) {
                return (EROFS);
        }

        pp->sectorsize = fd->sectorsize;
        pp->stripesize = fd->ft->heads * fd->ft->sectrac * fd->sectorsize;
        pp->mediasize = pp->stripesize * fd->ft->tracks;
        return (0);
}

static void
fd_start(struct bio *bp)
{
        struct fd_data *        fd;

        fd = bp->bio_to->geom->softc;
        bp->bio_driver1 = fd;
        if (bp->bio_cmd == BIO_GETATTR) {
                if (g_handleattr_int(bp, "GEOM::fwsectors", fd->ft->sectrac))
                        return;
                if (g_handleattr_int(bp, "GEOM::fwheads", fd->ft->heads))
                        return;
                g_io_deliver(bp, ENOIOCTL);
                return;
        }
        if (!(bp->bio_cmd == BIO_READ || bp->bio_cmd == BIO_WRITE)) {
                g_io_deliver(bp, EOPNOTSUPP);
                return;
        }
        bp->bio_pblkno = bp->bio_offset / fd->sectorsize;
        bp->bio_resid = bp->bio_length;
        fd_enqueue(fd, bp);
        return;
}

static int
fd_ioctl(struct g_provider *pp, u_long cmd, void *data, int fflag, struct thread *td)
{
        struct fd_data *fd;
        struct fdc_status *fsp;
        struct fdc_readid *rid;
        int error;

        fd = pp->geom->softc;

        switch (cmd) {
        case FD_GTYPE:                  /* get drive type */
                *(struct fd_type *)data = *fd->ft;
                return (0);

        case FD_STYPE:                  /* set drive type */
                /*
                 * Allow setting drive type temporarily iff
                 * currently unset.  Used for fdformat so any
                 * user can set it, and then start formatting.
                 */
                fd->fts = *(struct fd_type *)data;
                if (fd->fts.sectrac) {
                        /* XXX: check for rubbish */
                        fdsettype(fd, &fd->fts);
                } else {
                        fdsettype(fd, fd_native_types[fd->type]);
                }
                if (debugflags & 0x40)
                        fdprinttype(fd->ft);
                return (0);

        case FD_GOPTS:                  /* get drive options */
                *(int *)data = fd->options;
                return (0);

        case FD_SOPTS:                  /* set drive options */
                fd->options = *(int *)data;
                return (0);

        case FD_CLRERR:
                error = priv_check(td, PRIV_DRIVER);
                if (error)
                        return (error);
                fd->fdc->fdc_errs = 0;
                return (0);

        case FD_GSTAT:
                fsp = (struct fdc_status *)data;
                if ((fd->fdc->flags & FDC_STAT_VALID) == 0)
                        return (EINVAL);
                memcpy(fsp->status, fd->fdc->status, 7 * sizeof(u_int));
                return (0);

        case FD_GDTYPE:
                *(enum fd_drivetype *)data = fd->type;
                return (0);

        case FD_FORM:
                if (!(fflag & FWRITE))
                        return (EPERM);
                if (((struct fd_formb *)data)->format_version !=
                    FD_FORMAT_VERSION)
                        return (EINVAL); /* wrong version of formatting prog */
                error = fdmisccmd(fd, BIO_FMT, data);
                mtx_lock(&fd->fdc->fdc_mtx);
                fd->flags |= FD_NEWDISK;
                mtx_unlock(&fd->fdc->fdc_mtx);
                break;

        case FD_READID:
                rid = (struct fdc_readid *)data;
                if (rid->cyl > 85 || rid->head > 1)
                        return (EINVAL);
                error = fdmisccmd(fd, BIO_RDID, data);
                break;

        case FIONBIO:
        case FIOASYNC:
                /* For backwards compat with old fd*(8) tools */
                error = 0;
                break;

        default:
                if (debugflags & 0x80)
                        printf("Unknown ioctl %lx\n", cmd);
                error = ENOIOCTL;
                break;
        }
        return (error);
};

/*
 * Configuration/initialization stuff, per controller.
 */
struct fdc_ivars {
        int     fdunit;
        int     fdtype;
};

void
fdc_release_resources(struct fdc_data *fdc)
{
        device_t dev;
        struct resource *last;
        int i;

        dev = fdc->fdc_dev;
        if (fdc->fdc_intr)
                bus_teardown_intr(dev, fdc->res_irq, fdc->fdc_intr);
        fdc->fdc_intr = NULL;
        if (fdc->res_irq != NULL)
                bus_release_resource(dev, SYS_RES_IRQ, fdc->rid_irq,
                    fdc->res_irq);
        fdc->res_irq = NULL;
        last = NULL;
        for (i = 0; i < FDC_MAXREG; i++) {
                if (fdc->resio[i] != NULL && fdc->resio[i] != last) {
                        bus_release_resource(dev, SYS_RES_IOPORT,
                            fdc->ridio[i], fdc->resio[i]);
                        last = fdc->resio[i];
                        fdc->resio[i] = NULL;
                }
        }
        if (fdc->res_drq != NULL)
                bus_release_resource(dev, SYS_RES_DRQ, fdc->rid_drq,
                    fdc->res_drq);
        fdc->res_drq = NULL;
}

int
fdc_read_ivar(device_t dev, device_t child, int which, uintptr_t *result)
{
        struct fdc_ivars *ivars = device_get_ivars(child);

        switch (which) {
        case FDC_IVAR_FDUNIT:
                *result = ivars->fdunit;
                break;
        case FDC_IVAR_FDTYPE:
                *result = ivars->fdtype;
                break;
        default:
                return (ENOENT);
        }
        return (0);
}

int
fdc_write_ivar(device_t dev, device_t child, int which, uintptr_t value)
{
        struct fdc_ivars *ivars = device_get_ivars(child);

        switch (which) {
        case FDC_IVAR_FDUNIT:
                ivars->fdunit = value;
                break;
        case FDC_IVAR_FDTYPE:
                ivars->fdtype = value;
                break;
        default:
                return (ENOENT);
        }
        return (0);
}

int
fdc_initial_reset(device_t dev, struct fdc_data *fdc)
{
        int ic_type, part_id;

        /*
         * A status value of 0xff is very unlikely, but not theoretically
         * impossible, but it is far more likely to indicate an empty bus.
         */
        if (fdsts_rd(fdc) == 0xff)
                return (ENXIO);

        /*
         * Assert a reset to the floppy controller and check that the status
         * register goes to zero.
         */
        fdout_wr(fdc, 0);
        fdout_wr(fdc, 0);
        if (fdsts_rd(fdc) != 0)
                return (ENXIO);

        /*
         * Clear the reset and see it come ready.
         */
        fdout_wr(fdc, FDO_FRST);
        DELAY(100);
        if (fdsts_rd(fdc) != 0x80)
                return (ENXIO);

        /* Then, see if it can handle a command. */
        if (fdc_cmd(fdc, 3, NE7CMD_SPECIFY, NE7_SPEC_1(6, 240),
            NE7_SPEC_2(31, 0), 0))
                return (ENXIO);

        /*
         * Try to identify the chip.
         *
         * The i8272 datasheet documents that unknown commands
         * will return ST0 as 0x80.  The i8272 is supposedly identical
         * to the NEC765.
         * The i82077SL datasheet says 0x90 for the VERSION command,
         * and several "superio" chips emulate this.
         */
        if (fdc_cmd(fdc, 1, NE7CMD_VERSION, 1, &ic_type))
                return (ENXIO);
        if (fdc_cmd(fdc, 1, 0x18, 1, &part_id))
                return (ENXIO);
        if (bootverbose)
                device_printf(dev,
                    "ic_type %02x part_id %02x\n", ic_type, part_id);
        switch (ic_type & 0xff) {
        case 0x80:
                device_set_desc(dev, "NEC 765 or clone");
                fdc->fdct = FDC_NE765;
                break;
        case 0x81:
        case 0x90:
                device_set_desc(dev,
                    "Enhanced floppy controller");
                fdc->fdct = FDC_ENHANCED;
                break;
        default:
                device_set_desc(dev, "Generic floppy controller");
                fdc->fdct = FDC_UNKNOWN;
                break;
        }
        return (0);
}

int
fdc_detach(device_t dev)
{
        struct  fdc_data *fdc;
        int     error;

        fdc = device_get_softc(dev);

        /* have our children detached first */
        if ((error = bus_generic_detach(dev)))
                return (error);

        if (fdc->fdc_intr)
                bus_teardown_intr(dev, fdc->res_irq, fdc->fdc_intr);
        fdc->fdc_intr = NULL;

        /* kill worker thread */
        mtx_lock(&fdc->fdc_mtx);
        fdc->flags |= FDC_KTHREAD_EXIT;
        wakeup(&fdc->head);
        while ((fdc->flags & FDC_KTHREAD_ALIVE) != 0)
                msleep(fdc->fdc_thread, &fdc->fdc_mtx, PRIBIO, "fdcdet", 0);
        mtx_unlock(&fdc->fdc_mtx);

        /* reset controller, turn motor off */
        fdout_wr(fdc, 0);

        if (!(fdc->flags & FDC_NODMA))
                isa_dma_release(fdc->dmachan);
        fdc_release_resources(fdc);
        mtx_destroy(&fdc->fdc_mtx);
        return (0);
}

/*
 * Add a child device to the fdc controller.  It will then be probed etc.
 */
device_t
fdc_add_child(device_t dev, const char *name, int unit)
{
        struct fdc_ivars *ivar;
        device_t child;

        ivar = malloc(sizeof *ivar, M_DEVBUF /* XXX */, M_NOWAIT | M_ZERO);
        if (ivar == NULL)
                return (NULL);
        child = device_add_child(dev, name, unit);
        if (child == NULL) {
                free(ivar, M_DEVBUF);
                return (NULL);
        }
        device_set_ivars(child, ivar);
        ivar->fdunit = unit;
        ivar->fdtype = FDT_NONE;
        if (resource_disabled(name, unit))
                device_disable(child);
        return (child);
}

int
fdc_attach(device_t dev)
{
        struct  fdc_data *fdc;
        int     error;

        fdc = device_get_softc(dev);
        fdc->fdc_dev = dev;
        error = fdc_initial_reset(dev, fdc);
        if (error) {
                device_printf(dev, "does not respond\n");
                return (error);
        }
        error = bus_setup_intr(dev, fdc->res_irq,
            INTR_TYPE_BIO | INTR_ENTROPY | 
            ((fdc->flags & FDC_NOFAST) ? INTR_MPSAFE : 0),                     
            ((fdc->flags & FDC_NOFAST) ? NULL : fdc_intr_fast),             
            ((fdc->flags & FDC_NOFAST) ? fdc_intr : NULL), 
                               fdc, &fdc->fdc_intr);
        if (error) {
                device_printf(dev, "cannot setup interrupt\n");
                return (error);
        }
        if (!(fdc->flags & FDC_NODMA)) {
                error = isa_dma_acquire(fdc->dmachan);
                if (!error) {
                        error = isa_dma_init(fdc->dmachan,
                            MAX_BYTES_PER_CYL, M_WAITOK);
                        if (error)
                                isa_dma_release(fdc->dmachan);
                }
                if (error)
                        return (error);
        }
        fdc->fdcu = device_get_unit(dev);
        fdc->flags |= FDC_NEEDS_RESET;

        mtx_init(&fdc->fdc_mtx, "fdc lock", NULL, MTX_DEF);

        /* reset controller, turn motor off, clear fdout mirror reg */
        fdout_wr(fdc, fdc->fdout = 0);
        bioq_init(&fdc->head);

        settle = hz / 8;

        return (0);
}

void
fdc_start_worker(device_t dev)
{
        struct  fdc_data *fdc;

        fdc = device_get_softc(dev);
        kproc_create(fdc_thread, fdc, &fdc->fdc_thread, 0, 0,
            "fdc%d", device_get_unit(dev));
}

int
fdc_hints_probe(device_t dev)
{
        const char *name, *dname;
        int i, dunit;

        /*
         * Probe and attach any children.  We should probably detect
         * devices from the BIOS unless overridden.
         */
        name = device_get_nameunit(dev);
        i = 0;
        while ((resource_find_match(&i, &dname, &dunit, "at", name)) == 0) {
                resource_int_value(dname, dunit, "drive", &dunit);
                fdc_add_child(dev, dname, dunit);
        }

        bus_attach_children(dev);
        return (0);
}

int
fdc_print_child(device_t me, device_t child)
{
        int retval = 0, flags;

        retval += bus_print_child_header(me, child);
        retval += printf(" on %s drive %d", device_get_nameunit(me),
               fdc_get_fdunit(child));
        if ((flags = device_get_flags(me)) != 0)
                retval += printf(" flags %#x", flags);
        retval += printf("\n");

        return (retval);
}

/*
 * Configuration/initialization, per drive.
 */
static int
fd_probe(device_t dev)
{
#if defined(__i386__) || defined(__amd64__)
        int     unit;
#endif
        int     i;
        u_int   st0, st3;
        struct  fd_data *fd;
        struct  fdc_data *fdc;
        int     fdsu;
        int     flags, type;

        fdsu = fdc_get_fdunit(dev);
        fd = device_get_softc(dev);
        fdc = device_get_softc(device_get_parent(dev));
        flags = device_get_flags(dev);

        fd->dev = dev;
        fd->fdc = fdc;
        fd->fdsu = fdsu;

        /* Auto-probe if fdinfo is present, but always allow override. */
        type = flags & FD_TYPEMASK;
        if (type == FDT_NONE && (type = fdc_get_fdtype(dev)) != FDT_NONE) {
                fd->type = type;
                goto done;
        } else {
                /* make sure fdautoselect() will be called */
                fd->flags = FD_EMPTY;
                fd->type = type;
        }

#if defined(__i386__) || defined(__amd64__)
        unit = device_get_unit(dev);
        if (fd->type == FDT_NONE && (unit == 0 || unit == 1)) {
                /* Look up what the BIOS thinks we have. */
                if (unit == 0)
                        fd->type = (rtcin(RTC_FDISKETTE) & 0xf0) >> 4;
                else
                        fd->type = rtcin(RTC_FDISKETTE) & 0x0f;
                if (fd->type == FDT_288M_1)
                        fd->type = FDT_288M;
        }
#endif /* __i386__ || __amd64__ */
        /* is there a unit? */
        if (fd->type == FDT_NONE)
                return (ENXIO);

        mtx_lock(&fdc->fdc_mtx);

        /* select it */
        fd_select(fd);
        fd_motor(fd, 1);
        fdc->fd = fd;
        fdc_reset(fdc);         /* XXX reset, then unreset, etc. */
        DELAY(1000000); /* 1 sec */

        if ((flags & FD_NO_PROBE) == 0) {
                /* If we're at track 0 first seek inwards. */
                if ((fdc_sense_drive(fdc, &st3) == 0) &&
                    (st3 & NE7_ST3_T0)) {
                        /* Seek some steps... */
                        if (fdc_cmd(fdc, 3, NE7CMD_SEEK, fdsu, 10, 0) == 0) {
                                /* ...wait a moment... */
                                DELAY(300000);
                                /* make ctrlr happy: */
                                fdc_sense_int(fdc, NULL, NULL);
                        }
                }

                for (i = 0; i < 2; i++) {
                        /*
                         * we must recalibrate twice, just in case the
                         * heads have been beyond cylinder 76, since
                         * most FDCs still barf when attempting to
                         * recalibrate more than 77 steps
                         */
                        /* go back to 0: */
                        if (fdc_cmd(fdc, 2, NE7CMD_RECAL, fdsu, 0) == 0) {
                                /* a second being enough for full stroke seek*/
                                DELAY(i == 0 ? 1000000 : 300000);

                                /* anything responding? */
                                if (fdc_sense_int(fdc, &st0, NULL) == 0 &&
                                    (st0 & NE7_ST0_EC) == 0)
                                        break; /* already probed successfully */
                        }
                }
        }

        fd_motor(fd, 0);
        fdc->fd = NULL;
        mtx_unlock(&fdc->fdc_mtx);

        if ((flags & FD_NO_PROBE) == 0 &&
            (st0 & NE7_ST0_EC) != 0) /* no track 0 -> no drive present */
                return (ENXIO);

done:

        switch (fd->type) {
        case FDT_12M:
                device_set_desc(dev, "1200-KB 5.25\" drive");
                break;
        case FDT_144M:
                device_set_desc(dev, "1440-KB 3.5\" drive");
                break;
        case FDT_288M:
                device_set_desc(dev, "2880-KB 3.5\" drive (in 1440-KB mode)");
                break;
        case FDT_360K:
                device_set_desc(dev, "360-KB 5.25\" drive");
                break;
        case FDT_720K:
                device_set_desc(dev, "720-KB 3.5\" drive");
                break;
        default:
                return (ENXIO);
        }
        fd->track = FD_NO_TRACK;
        fd->fdc = fdc;
        fd->fdsu = fdsu;
        fd->options = 0;
        callout_init_mtx(&fd->toffhandle, &fd->fdc->fdc_mtx, 0);

        /* initialize densities for subdevices */
        fdsettype(fd, fd_native_types[fd->type]);
        return (0);
}

/*
 * We have to do this in a geom event because GEOM is not running
 * when fd_attach() is.
 * XXX: move fd_attach after geom like ata/scsi disks
 */
static void
fd_attach2(void *arg, int flag)
{
        struct  fd_data *fd;

        fd = arg;

        fd->fd_geom = g_new_geomf(&g_fd_class,
            "fd%d", device_get_unit(fd->dev));
        fd->fd_provider = g_new_providerf(fd->fd_geom, "%s", fd->fd_geom->name);
        fd->fd_geom->softc = fd;
        g_error_provider(fd->fd_provider, 0);
}

static int
fd_attach(device_t dev)
{
        struct  fd_data *fd;

        fd = device_get_softc(dev);
        g_post_event(fd_attach2, fd, M_WAITOK, NULL);
        fd->flags |= FD_EMPTY;
        bioq_init(&fd->fd_bq);

        return (0);
}

static void
fd_providergone(struct g_provider *pp)
{
        struct fd_data *fd;

        fd = pp->geom->softc;
        fd->gone = true;
        wakeup(fd);
}

static void
fd_detach_geom(void *arg, int flag)
{
        struct  fd_data *fd = arg;

        g_topology_assert();
        g_wither_geom(fd->fd_geom, ENXIO);
}

static int
fd_detach(device_t dev)
{
        struct  fd_data *fd;

        fd = device_get_softc(dev);

        g_waitfor_event(fd_detach_geom, fd, M_WAITOK, NULL);
        while (!fd->gone) {
                tsleep(fd, PZERO, "fdgone", hz/10);
        }

        /*
         * There may be accesses to the floppy while we're waitng, so drain the
         * motor callback here. fdc_detach turns off motor if it's still on when
         * we get to this point.
         */
        callout_drain(&fd->toffhandle);

        return (0);
}

static device_method_t fd_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe,         fd_probe),
        DEVMETHOD(device_attach,        fd_attach),
        DEVMETHOD(device_detach,        fd_detach),
        DEVMETHOD(device_shutdown,      bus_generic_shutdown),
        DEVMETHOD(device_suspend,       bus_generic_suspend), /* XXX */
        DEVMETHOD(device_resume,        bus_generic_resume), /* XXX */
        DEVMETHOD_END
};

static driver_t fd_driver = {
        "fd",
        fd_methods,
        sizeof(struct fd_data)
};

static int
fdc_modevent(module_t mod, int type, void *data)
{

        return (g_modevent(NULL, type, &g_fd_class));
}

DRIVER_MODULE(fd, fdc, fd_driver, fdc_modevent, 0);