/*
 *  linux/drivers/block/floppy.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *  Copyright (C) 1993, 1994  Alain Knaff
 *  Copyright (C) 1998 Alan Cox
 */

/*
 * 02.12.91 - Changed to static variables to indicate need for reset
 * and recalibrate. This makes some things easier (output_byte reset
 * checking etc), and means less interrupt jumping in case of errors,
 * so the code is hopefully easier to understand.
 */

/*
 * This file is certainly a mess. I've tried my best to get it working,
 * but I don't like programming floppies, and I have only one anyway.
 * Urgel. I should check for more errors, and do more graceful error
 * recovery. Seems there are problems with several drives. I've tried to
 * correct them. No promises.
 */

/*
 * As with hd.c, all routines within this file can (and will) be called
 * by interrupts, so extreme caution is needed. A hardware interrupt
 * handler may not sleep, or a kernel panic will happen. Thus I cannot
 * call "floppy-on" directly, but have to set a special timer interrupt
 * etc.
 */

/*
 * 28.02.92 - made track-buffering routines, based on the routines written
 * by entropy@wintermute.wpi.edu (Lawrence Foard). Linus.
 */

/*
 * Automatic floppy-detection and formatting written by Werner Almesberger
 * (almesber@nessie.cs.id.ethz.ch), who also corrected some problems with
 * the floppy-change signal detection.
 */

/*
 * 1992/7/22 -- Hennus Bergman: Added better error reporting, fixed
 * FDC data overrun bug, added some preliminary stuff for vertical
 * recording support.
 *
 * 1992/9/17: Added DMA allocation & DMA functions. -- hhb.
 *
 * TODO: Errors are still not counted properly.
 */

/* 1992/9/20
 * Modifications for ``Sector Shifting'' by Rob Hooft (hooft@chem.ruu.nl)
 * modeled after the freeware MS-DOS program fdformat/88 V1.8 by
 * Christoph H. Hochst\"atter.
 * I have fixed the shift values to the ones I always use. Maybe a new
 * ioctl() should be created to be able to modify them.
 * There is a bug in the driver that makes it impossible to format a
 * floppy as the first thing after bootup.
 */

/*
 * 1993/4/29 -- Linus -- cleaned up the timer handling in the kernel, and
 * this helped the floppy driver as well. Much cleaner, and still seems to
 * work.
 */

/* 1994/6/24 --bbroad-- added the floppy table entries and made
 * minor modifications to allow 2.88 floppies to be run.
 */

/* 1994/7/13 -- Paul Vojta -- modified the probing code to allow three or more
 * disk types.
 */

/*
 * 1994/8/8 -- Alain Knaff -- Switched to fdpatch driver: Support for bigger
 * format bug fixes, but unfortunately some new bugs too...
 */

/* 1994/9/17 -- Koen Holtman -- added logging of physical floppy write
 * errors to allow safe writing by specialized programs.
 */

/* 1995/4/24 -- Dan Fandrich -- added support for Commodore 1581 3.5" disks
 * by defining bit 1 of the "stretch" parameter to mean put sectors on the
 * opposite side of the disk, leaving the sector IDs alone (i.e. Commodore's
 * drives are "upside-down").
 */

/*
 * 1995/8/26 -- Andreas Busse -- added Mips support.
 */

/*
 * 1995/10/18 -- Ralf Baechle -- Portability cleanup; move machine dependent
 * features to asm/floppy.h.
 */

/*
 * 1998/1/21 -- Richard Gooch <rgooch@atnf.csiro.au> -- devfs support
 */

/*
 * 1998/05/07 -- Russell King -- More portability cleanups; moved definition of
 * interrupt and dma channel to asm/floppy.h. Cleaned up some formatting &
 * use of '0' for NULL.
 */

/*
 * 1998/06/07 -- Alan Cox -- Merged the 2.0.34 fixes for resource allocation
 * failures.
 */

/*
 * 1998/09/20 -- David Weinehall -- Added slow-down code for buggy PS/2-drives.
 */

/*
 * 1999/08/13 -- Paul Slootman -- floppy stopped working on Alpha after 24
 * days, 6 hours, 32 minutes and 32 seconds (i.e. MAXINT jiffies; ints were
 * being used to store jiffies, which are unsigned longs).
 */

/*
 * 2000/08/28 -- Arnaldo Carvalho de Melo <acme@conectiva.com.br>
 * - get rid of check_region
 * - s/suser/capable/
 */

/*
 * 2001/08/26 -- Paul Gortmaker - fix insmod oops on machines with no
 * floppy controller (lingering task on list after module is gone... boom.)
 */

/*
 * 2002/02/07 -- Anton Altaparmakov - Fix io ports reservation to correct range
 * (0x3f2-0x3f5, 0x3f7). This fix is a bit of a hack but the proper fix
 * requires many non-obvious changes in arch dependent code.
 */

/* 2003/07/28 -- Daniele Bellucci <bellucda@tiscali.it>.
 * Better audit of register_blkdev.
 */

#define FLOPPY_SANITY_CHECK
#undef  FLOPPY_SILENT_DCL_CLEAR

#define REALLY_SLOW_IO

#define DEBUGT 2
#define DCL_DEBUG       /* debug disk change line */

/* do print messages for unexpected interrupts */
static int print_unex = 1;
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/timer.h>
#include <linux/workqueue.h>
#define FDPATCHES
#include <linux/fdreg.h>
#include <linux/fd.h>
#include <linux/hdreg.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/bio.h>
#include <linux/string.h>
#include <linux/jiffies.h>
#include <linux/fcntl.h>
#include <linux/delay.h>
#include <linux/mc146818rtc.h>  /* CMOS defines */
#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/mod_devicetable.h>
#include <linux/buffer_head.h>  /* for invalidate_buffers() */
#include <linux/mutex.h>

/*
 * PS/2 floppies have much slower step rates than regular floppies.
 * It's been recommended that take about 1/4 of the default speed
 * in some more extreme cases.
 */
static int slow_floppy;

#include <asm/dma.h>
#include <asm/irq.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/uaccess.h>

static int FLOPPY_IRQ = 6;
static int FLOPPY_DMA = 2;
static int can_use_virtual_dma = 2;
/* =======
 * can use virtual DMA:
 * 0 = use of virtual DMA disallowed by config
 * 1 = use of virtual DMA prescribed by config
 * 2 = no virtual DMA preference configured.  By default try hard DMA,
 * but fall back on virtual DMA when not enough memory available
 */

static int use_virtual_dma;
/* =======
 * use virtual DMA
 * 0 using hard DMA
 * 1 using virtual DMA
 * This variable is set to virtual when a DMA mem problem arises, and
 * reset back in floppy_grab_irq_and_dma.
 * It is not safe to reset it in other circumstances, because the floppy
 * driver may have several buffers in use at once, and we do currently not
 * record each buffers capabilities
 */

static DEFINE_SPINLOCK(floppy_lock);

static unsigned short virtual_dma_port = 0x3f0;
irqreturn_t floppy_interrupt(int irq, void *dev_id);
static int set_dor(int fdc, char mask, char data);

#define K_64    0x10000         /* 64KB */

/* the following is the mask of allowed drives. By default units 2 and
 * 3 of both floppy controllers are disabled, because switching on the
 * motor of these drives causes system hangs on some PCI computers. drive
 * 0 is the low bit (0x1), and drive 7 is the high bit (0x80). Bits are on if
 * a drive is allowed.
 *
 * NOTE: This must come before we include the arch floppy header because
 *       some ports reference this variable from there. -DaveM
 */

static int allowed_drive_mask = 0x33;

#include <asm/floppy.h>

static int irqdma_allocated;

#define DEVICE_NAME "floppy"

#include <linux/blkdev.h>
#include <linux/blkpg.h>
#include <linux/cdrom.h>        /* for the compatibility eject ioctl */
#include <linux/completion.h>

static struct request *current_req;
static struct request_queue *floppy_queue;
static void do_fd_request(struct request_queue * q);

#ifndef fd_get_dma_residue
#define fd_get_dma_residue() get_dma_residue(FLOPPY_DMA)
#endif

/* Dma Memory related stuff */

#ifndef fd_dma_mem_free
#define fd_dma_mem_free(addr, size) free_pages(addr, get_order(size))
#endif

#ifndef fd_dma_mem_alloc
#define fd_dma_mem_alloc(size) __get_dma_pages(GFP_KERNEL,get_order(size))
#endif

static inline void fallback_on_nodma_alloc(char **addr, size_t l)
{
#ifdef FLOPPY_CAN_FALLBACK_ON_NODMA
        if (*addr)
                return;         /* we have the memory */
        if (can_use_virtual_dma != 2)
                return;         /* no fallback allowed */
        printk("DMA memory shortage. Temporarily falling back on virtual DMA\n");
        *addr = (char *)nodma_mem_alloc(l);
#else
        return;
#endif
}

/* End dma memory related stuff */

static unsigned long fake_change;
static int initialising = 1;

#define ITYPE(x) (((x)>>2) & 0x1f)
#define TOMINOR(x) ((x & 3) | ((x & 4) << 5))
#define UNIT(x) ((x) & 0x03)    /* drive on fdc */
#define FDC(x) (((x) & 0x04) >> 2)      /* fdc of drive */
        /* reverse mapping from unit and fdc to drive */
#define REVDRIVE(fdc, unit) ((unit) + ((fdc) << 2))
#define DP (&drive_params[current_drive])
#define DRS (&drive_state[current_drive])
#define DRWE (&write_errors[current_drive])
#define FDCS (&fdc_state[fdc])
#define CLEARF(x) clear_bit(x##_BIT, &DRS->flags)
#define SETF(x) set_bit(x##_BIT, &DRS->flags)
#define TESTF(x) test_bit(x##_BIT, &DRS->flags)

#define UDP (&drive_params[drive])
#define UDRS (&drive_state[drive])
#define UDRWE (&write_errors[drive])
#define UFDCS (&fdc_state[FDC(drive)])
#define UCLEARF(x) clear_bit(x##_BIT, &UDRS->flags)
#define USETF(x) set_bit(x##_BIT, &UDRS->flags)
#define UTESTF(x) test_bit(x##_BIT, &UDRS->flags)

#define DPRINT(format, args...) printk(DEVICE_NAME "%d: " format, current_drive , ## args)

#define PH_HEAD(floppy,head) (((((floppy)->stretch & 2) >>1) ^ head) << 2)
#define STRETCH(floppy) ((floppy)->stretch & FD_STRETCH)

#define CLEARSTRUCT(x) memset((x), 0, sizeof(*(x)))

/* read/write */
#define COMMAND raw_cmd->cmd[0]
#define DR_SELECT raw_cmd->cmd[1]
#define TRACK raw_cmd->cmd[2]
#define HEAD raw_cmd->cmd[3]
#define SECTOR raw_cmd->cmd[4]
#define SIZECODE raw_cmd->cmd[5]
#define SECT_PER_TRACK raw_cmd->cmd[6]
#define GAP raw_cmd->cmd[7]
#define SIZECODE2 raw_cmd->cmd[8]
#define NR_RW 9

/* format */
#define F_SIZECODE raw_cmd->cmd[2]
#define F_SECT_PER_TRACK raw_cmd->cmd[3]
#define F_GAP raw_cmd->cmd[4]
#define F_FILL raw_cmd->cmd[5]
#define NR_F 6

/*
 * Maximum disk size (in kilobytes). This default is used whenever the
 * current disk size is unknown.
 * [Now it is rather a minimum]
 */
#define MAX_DISK_SIZE 4         /* 3984 */

/*
 * globals used by 'result()'
 */
#define MAX_REPLIES 16
static unsigned char reply_buffer[MAX_REPLIES];
static int inr;                 /* size of reply buffer, when called from interrupt */
#define ST0 (reply_buffer[0])
#define ST1 (reply_buffer[1])
#define ST2 (reply_buffer[2])
#define ST3 (reply_buffer[0])   /* result of GETSTATUS */
#define R_TRACK (reply_buffer[3])
#define R_HEAD (reply_buffer[4])
#define R_SECTOR (reply_buffer[5])
#define R_SIZECODE (reply_buffer[6])
#define SEL_DLY (2*HZ/100)

/*
 * this struct defines the different floppy drive types.
 */
static struct {
        struct floppy_drive_params params;
        const char *name;       /* name printed while booting */
} default_drive_params[] = {
/* NOTE: the time values in jiffies should be in msec!
 CMOS drive type
  |     Maximum data rate supported by drive type
  |     |   Head load time, msec
  |     |   |   Head unload time, msec (not used)
  |     |   |   |     Step rate interval, usec
  |     |   |   |     |       Time needed for spinup time (jiffies)
  |     |   |   |     |       |      Timeout for spinning down (jiffies)
  |     |   |   |     |       |      |   Spindown offset (where disk stops)
  |     |   |   |     |       |      |   |     Select delay
  |     |   |   |     |       |      |   |     |     RPS
  |     |   |   |     |       |      |   |     |     |    Max number of tracks
  |     |   |   |     |       |      |   |     |     |    |     Interrupt timeout
  |     |   |   |     |       |      |   |     |     |    |     |   Max nonintlv. sectors
  |     |   |   |     |       |      |   |     |     |    |     |   | -Max Errors- flags */
{{0,  500, 16, 16, 8000,    1*HZ, 3*HZ,  0, SEL_DLY, 5,  80, 3*HZ, 20, {3,1,2,0,2}, 0,
      0, { 7, 4, 8, 2, 1, 5, 3,10}, 3*HZ/2, 0 }, "unknown" },

{{1,  300, 16, 16, 8000,    1*HZ, 3*HZ,  0, SEL_DLY, 5,  40, 3*HZ, 17, {3,1,2,0,2}, 0,
      0, { 1, 0, 0, 0, 0, 0, 0, 0}, 3*HZ/2, 1 }, "360K PC" }, /*5 1/4 360 KB PC*/

{{2,  500, 16, 16, 6000, 4*HZ/10, 3*HZ, 14, SEL_DLY, 6,  83, 3*HZ, 17, {3,1,2,0,2}, 0,
      0, { 2, 5, 6,23,10,20,12, 0}, 3*HZ/2, 2 }, "1.2M" }, /*5 1/4 HD AT*/

{{3,  250, 16, 16, 3000,    1*HZ, 3*HZ,  0, SEL_DLY, 5,  83, 3*HZ, 20, {3,1,2,0,2}, 0,
      0, { 4,22,21,30, 3, 0, 0, 0}, 3*HZ/2, 4 }, "720k" }, /*3 1/2 DD*/

{{4,  500, 16, 16, 4000, 4*HZ/10, 3*HZ, 10, SEL_DLY, 5,  83, 3*HZ, 20, {3,1,2,0,2}, 0,
      0, { 7, 4,25,22,31,21,29,11}, 3*HZ/2, 7 }, "1.44M" }, /*3 1/2 HD*/

{{5, 1000, 15,  8, 3000, 4*HZ/10, 3*HZ, 10, SEL_DLY, 5,  83, 3*HZ, 40, {3,1,2,0,2}, 0,
      0, { 7, 8, 4,25,28,22,31,21}, 3*HZ/2, 8 }, "2.88M AMI BIOS" }, /*3 1/2 ED*/

{{6, 1000, 15,  8, 3000, 4*HZ/10, 3*HZ, 10, SEL_DLY, 5,  83, 3*HZ, 40, {3,1,2,0,2}, 0,
      0, { 7, 8, 4,25,28,22,31,21}, 3*HZ/2, 8 }, "2.88M" } /*3 1/2 ED*/
/*    |  --autodetected formats---    |      |      |
 *    read_track                      |      |    Name printed when booting
 *                                    |     Native format
 *                  Frequency of disk change checks */
};

static struct floppy_drive_params drive_params[N_DRIVE];
static struct floppy_drive_struct drive_state[N_DRIVE];
static struct floppy_write_errors write_errors[N_DRIVE];
static struct timer_list motor_off_timer[N_DRIVE];
static struct gendisk *disks[N_DRIVE];
static struct block_device *opened_bdev[N_DRIVE];
static DEFINE_MUTEX(open_lock);
static struct floppy_raw_cmd *raw_cmd, default_raw_cmd;

/*
 * This struct defines the different floppy types.
 *
 * Bit 0 of 'stretch' tells if the tracks need to be doubled for some
 * types (e.g. 360kB diskette in 1.2MB drive, etc.).  Bit 1 of 'stretch'
 * tells if the disk is in Commodore 1581 format, which means side 0 sectors
 * are located on side 1 of the disk but with a side 0 ID, and vice-versa.
 * This is the same as the Sharp MZ-80 5.25" CP/M disk format, except that the
 * 1581's logical side 0 is on physical side 1, whereas the Sharp's logical
 * side 0 is on physical side 0 (but with the misnamed sector IDs).
 * 'stretch' should probably be renamed to something more general, like
 * 'options'.  Other parameters should be self-explanatory (see also
 * setfdprm(8)).
 */
/*
            Size
             |  Sectors per track
             |  | Head
             |  | |  Tracks
             |  | |  | Stretch
             |  | |  | |  Gap 1 size
             |  | |  | |    |  Data rate, | 0x40 for perp
             |  | |  | |    |    |  Spec1 (stepping rate, head unload
             |  | |  | |    |    |    |    /fmt gap (gap2) */
static struct floppy_struct floppy_type[32] = {
        {    0, 0,0, 0,0,0x00,0x00,0x00,0x00,NULL    }, /*  0 no testing    */
        {  720, 9,2,40,0,0x2A,0x02,0xDF,0x50,"d360"  }, /*  1 360KB PC      */
        { 2400,15,2,80,0,0x1B,0x00,0xDF,0x54,"h1200" }, /*  2 1.2MB AT      */
        {  720, 9,1,80,0,0x2A,0x02,0xDF,0x50,"D360"  }, /*  3 360KB SS 3.5" */
        { 1440, 9,2,80,0,0x2A,0x02,0xDF,0x50,"D720"  }, /*  4 720KB 3.5"    */
        {  720, 9,2,40,1,0x23,0x01,0xDF,0x50,"h360"  }, /*  5 360KB AT      */
        { 1440, 9,2,80,0,0x23,0x01,0xDF,0x50,"h720"  }, /*  6 720KB AT      */
        { 2880,18,2,80,0,0x1B,0x00,0xCF,0x6C,"H1440" }, /*  7 1.44MB 3.5"   */
        { 5760,36,2,80,0,0x1B,0x43,0xAF,0x54,"E2880" }, /*  8 2.88MB 3.5"   */
        { 6240,39,2,80,0,0x1B,0x43,0xAF,0x28,"E3120" }, /*  9 3.12MB 3.5"   */

        { 2880,18,2,80,0,0x25,0x00,0xDF,0x02,"h1440" }, /* 10 1.44MB 5.25"  */
        { 3360,21,2,80,0,0x1C,0x00,0xCF,0x0C,"H1680" }, /* 11 1.68MB 3.5"   */
        {  820,10,2,41,1,0x25,0x01,0xDF,0x2E,"h410"  }, /* 12 410KB 5.25"   */
        { 1640,10,2,82,0,0x25,0x02,0xDF,0x2E,"H820"  }, /* 13 820KB 3.5"    */
        { 2952,18,2,82,0,0x25,0x00,0xDF,0x02,"h1476" }, /* 14 1.48MB 5.25"  */
        { 3444,21,2,82,0,0x25,0x00,0xDF,0x0C,"H1722" }, /* 15 1.72MB 3.5"   */
        {  840,10,2,42,1,0x25,0x01,0xDF,0x2E,"h420"  }, /* 16 420KB 5.25"   */
        { 1660,10,2,83,0,0x25,0x02,0xDF,0x2E,"H830"  }, /* 17 830KB 3.5"    */
        { 2988,18,2,83,0,0x25,0x00,0xDF,0x02,"h1494" }, /* 18 1.49MB 5.25"  */
        { 3486,21,2,83,0,0x25,0x00,0xDF,0x0C,"H1743" }, /* 19 1.74 MB 3.5"  */

        { 1760,11,2,80,0,0x1C,0x09,0xCF,0x00,"h880"  }, /* 20 880KB 5.25"   */
        { 2080,13,2,80,0,0x1C,0x01,0xCF,0x00,"D1040" }, /* 21 1.04MB 3.5"   */
        { 2240,14,2,80,0,0x1C,0x19,0xCF,0x00,"D1120" }, /* 22 1.12MB 3.5"   */
        { 3200,20,2,80,0,0x1C,0x20,0xCF,0x2C,"h1600" }, /* 23 1.6MB 5.25"   */
        { 3520,22,2,80,0,0x1C,0x08,0xCF,0x2e,"H1760" }, /* 24 1.76MB 3.5"   */
        { 3840,24,2,80,0,0x1C,0x20,0xCF,0x00,"H1920" }, /* 25 1.92MB 3.5"   */
        { 6400,40,2,80,0,0x25,0x5B,0xCF,0x00,"E3200" }, /* 26 3.20MB 3.5"   */
        { 7040,44,2,80,0,0x25,0x5B,0xCF,0x00,"E3520" }, /* 27 3.52MB 3.5"   */
        { 7680,48,2,80,0,0x25,0x63,0xCF,0x00,"E3840" }, /* 28 3.84MB 3.5"   */
        { 3680,23,2,80,0,0x1C,0x10,0xCF,0x00,"H1840" }, /* 29 1.84MB 3.5"   */

        { 1600,10,2,80,0,0x25,0x02,0xDF,0x2E,"D800"  }, /* 30 800KB 3.5"    */
        { 3200,20,2,80,0,0x1C,0x00,0xCF,0x2C,"H1600" }, /* 31 1.6MB 3.5"    */
};

#define SECTSIZE (_FD_SECTSIZE(*floppy))

/* Auto-detection: Disk type used until the next media change occurs. */
static struct floppy_struct *current_type[N_DRIVE];

/*
 * User-provided type information. current_type points to
 * the respective entry of this array.
 */
static struct floppy_struct user_params[N_DRIVE];

static sector_t floppy_sizes[256];

static char floppy_device_name[] = "floppy";

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

/* Synchronization of FDC access. */
#define FD_COMMAND_NONE -1
#define FD_COMMAND_ERROR 2
#define FD_COMMAND_OKAY 3

static volatile int command_status = FD_COMMAND_NONE;
static unsigned long fdc_busy;
static DECLARE_WAIT_QUEUE_HEAD(fdc_wait);
static DECLARE_WAIT_QUEUE_HEAD(command_done);

#define NO_SIGNAL (!interruptible || !signal_pending(current))
#define CALL(x) if ((x) == -EINTR) return -EINTR
#define ECALL(x) if ((ret = (x))) return ret;
#define _WAIT(x,i) CALL(ret=wait_til_done((x),i))
#define WAIT(x) _WAIT((x),interruptible)
#define IWAIT(x) _WAIT((x),1)

/* Errors during formatting are counted here. */
static int format_errors;

/* Format request descriptor. */
static struct format_descr format_req;

/*
 * Rate is 0 for 500kb/s, 1 for 300kbps, 2 for 250kbps
 * Spec1 is 0xSH, where S is stepping rate (F=1ms, E=2ms, D=3ms etc),
 * H is head unload time (1=16ms, 2=32ms, etc)
 */

/*
 * Track buffer
 * Because these are written to by the DMA controller, they must
 * not contain a 64k byte boundary crossing, or data will be
 * corrupted/lost.
 */
static char *floppy_track_buffer;
static int max_buffer_sectors;

static int *errors;
typedef void (*done_f)(int);
static struct cont_t {
        void (*interrupt)(void);        /* this is called after the interrupt of the
                                         * main command */
        void (*redo)(void);     /* this is called to retry the operation */
        void (*error)(void);    /* this is called to tally an error */
        done_f done;            /* this is called to say if the operation has
                                 * succeeded/failed */
} *cont;

static void floppy_ready(void);
static void floppy_start(void);
static void process_fd_request(void);
static void recalibrate_floppy(void);
static void floppy_shutdown(unsigned long);

static int floppy_request_regions(int);
static void floppy_release_regions(int);
static int floppy_grab_irq_and_dma(void);
static void floppy_release_irq_and_dma(void);

/*
 * The "reset" variable should be tested whenever an interrupt is scheduled,
 * after the commands have been sent. This is to ensure that the driver doesn't
 * get wedged when the interrupt doesn't come because of a failed command.
 * reset doesn't need to be tested before sending commands, because
 * output_byte is automatically disabled when reset is set.
 */
#define CHECK_RESET { if (FDCS->reset){ reset_fdc(); return; } }
static void reset_fdc(void);

/*
 * These are global variables, as that's the easiest way to give
 * information to interrupts. They are the data used for the current
 * request.
 */
#define NO_TRACK -1
#define NEED_1_RECAL -2
#define NEED_2_RECAL -3

static int usage_count;

/* buffer related variables */
static int buffer_track = -1;
static int buffer_drive = -1;
static int buffer_min = -1;
static int buffer_max = -1;

/* fdc related variables, should end up in a struct */
static struct floppy_fdc_state fdc_state[N_FDC];
static int fdc;                 /* current fdc */

static struct floppy_struct *_floppy = floppy_type;
static unsigned char current_drive;
static long current_count_sectors;
static unsigned char fsector_t; /* sector in track */
static unsigned char in_sector_offset;  /* offset within physical sector,
                                         * expressed in units of 512 bytes */

#ifndef fd_eject
static inline int fd_eject(int drive)
{
        return -EINVAL;
}
#endif

/*
 * Debugging
 * =========
 */
#ifdef DEBUGT
static long unsigned debugtimer;

static inline void set_debugt(void)
{
        debugtimer = jiffies;
}

static inline void debugt(const char *message)
{
        if (DP->flags & DEBUGT)
                printk("%s dtime=%lu\n", message, jiffies - debugtimer);
}
#else
static inline void set_debugt(void) { }
static inline void debugt(const char *message) { }
#endif /* DEBUGT */

typedef void (*timeout_fn) (unsigned long);
static DEFINE_TIMER(fd_timeout, floppy_shutdown, 0, 0);

static const char *timeout_message;

#ifdef FLOPPY_SANITY_CHECK
static void is_alive(const char *message)
{
        /* this routine checks whether the floppy driver is "alive" */
        if (test_bit(0, &fdc_busy) && command_status < 2
            && !timer_pending(&fd_timeout)) {
                DPRINT("timeout handler died: %s\n", message);
        }
}
#endif

static void (*do_floppy) (void) = NULL;

#ifdef FLOPPY_SANITY_CHECK

#define OLOGSIZE 20

static void (*lasthandler) (void);
static unsigned long interruptjiffies;
static unsigned long resultjiffies;
static int resultsize;
static unsigned long lastredo;

static struct output_log {
        unsigned char data;
        unsigned char status;
        unsigned long jiffies;
} output_log[OLOGSIZE];

static int output_log_pos;
#endif

#define current_reqD -1
#define MAXTIMEOUT -2

static void __reschedule_timeout(int drive, const char *message, int marg)
{
        if (drive == current_reqD)
                drive = current_drive;
        del_timer(&fd_timeout);
        if (drive < 0 || drive >= N_DRIVE) {
                fd_timeout.expires = jiffies + 20UL * HZ;
                drive = 0;
        } else
                fd_timeout.expires = jiffies + UDP->timeout;
        add_timer(&fd_timeout);
        if (UDP->flags & FD_DEBUG) {
                DPRINT("reschedule timeout ");
                printk(message, marg);
                printk("\n");
        }
        timeout_message = message;
}

static void reschedule_timeout(int drive, const char *message, int marg)
{
        unsigned long flags;

        spin_lock_irqsave(&floppy_lock, flags);
        __reschedule_timeout(drive, message, marg);
        spin_unlock_irqrestore(&floppy_lock, flags);
}

#define INFBOUND(a,b) (a)=max_t(int, a, b)
#define SUPBOUND(a,b) (a)=min_t(int, a, b)

/*
 * Bottom half floppy driver.
 * ==========================
 *
 * This part of the file contains the code talking directly to the hardware,
 * and also the main service loop (seek-configure-spinup-command)
 */

/*
 * disk change.
 * This routine is responsible for maintaining the FD_DISK_CHANGE flag,
 * and the last_checked date.
 *
 * last_checked is the date of the last check which showed 'no disk change'
 * FD_DISK_CHANGE is set under two conditions:
 * 1. The floppy has been changed after some i/o to that floppy already
 *    took place.
 * 2. No floppy disk is in the drive. This is done in order to ensure that
 *    requests are quickly flushed in case there is no disk in the drive. It
 *    follows that FD_DISK_CHANGE can only be cleared if there is a disk in
 *    the drive.
 *
 * For 1., maxblock is observed. Maxblock is 0 if no i/o has taken place yet.
 * For 2., FD_DISK_NEWCHANGE is watched. FD_DISK_NEWCHANGE is cleared on
 *  each seek. If a disk is present, the disk change line should also be
 *  cleared on each seek. Thus, if FD_DISK_NEWCHANGE is clear, but the disk
 *  change line is set, this means either that no disk is in the drive, or
 *  that it has been removed since the last seek.
 *
 * This means that we really have a third possibility too:
 *  The floppy has been changed after the last seek.
 */

static int disk_change(int drive)
{
        int fdc = FDC(drive);

#ifdef FLOPPY_SANITY_CHECK
        if (time_before(jiffies, UDRS->select_date + UDP->select_delay))
                DPRINT("WARNING disk change called early\n");
        if (!(FDCS->dor & (0x10 << UNIT(drive))) ||
            (FDCS->dor & 3) != UNIT(drive) || fdc != FDC(drive)) {
                DPRINT("probing disk change on unselected drive\n");
                DPRINT("drive=%d fdc=%d dor=%x\n", drive, FDC(drive),
                       (unsigned int)FDCS->dor);
        }
#endif

#ifdef DCL_DEBUG
        if (UDP->flags & FD_DEBUG) {
                DPRINT("checking disk change line for drive %d\n", drive);
                DPRINT("jiffies=%lu\n", jiffies);
                DPRINT("disk change line=%x\n", fd_inb(FD_DIR) & 0x80);
                DPRINT("flags=%lx\n", UDRS->flags);
        }
#endif
        if (UDP->flags & FD_BROKEN_DCL)
                return UTESTF(FD_DISK_CHANGED);
        if ((fd_inb(FD_DIR) ^ UDP->flags) & 0x80) {
                USETF(FD_VERIFY);       /* verify write protection */
                if (UDRS->maxblock) {
                        /* mark it changed */
                        USETF(FD_DISK_CHANGED);
                }

                /* invalidate its geometry */
                if (UDRS->keep_data >= 0) {
                        if ((UDP->flags & FTD_MSG) &&
                            current_type[drive] != NULL)
                                DPRINT("Disk type is undefined after "
                                       "disk change\n");
                        current_type[drive] = NULL;
                        floppy_sizes[TOMINOR(drive)] = MAX_DISK_SIZE << 1;
                }

                return 1;
        } else {
                UDRS->last_checked = jiffies;
                UCLEARF(FD_DISK_NEWCHANGE);
        }
        return 0;
}

static inline int is_selected(int dor, int unit)
{
        return ((dor & (0x10 << unit)) && (dor & 3) == unit);
}

static int set_dor(int fdc, char mask, char data)
{
        unsigned char unit;
        unsigned char drive;
        unsigned char newdor;
        unsigned char olddor;

        if (FDCS->address == -1)
                return -1;

        olddor = FDCS->dor;
        newdor = (olddor & mask) | data;
        if (newdor != olddor) {
                unit = olddor & 0x3;
                if (is_selected(olddor, unit) && !is_selected(newdor, unit)) {
                        drive = REVDRIVE(fdc, unit);
#ifdef DCL_DEBUG
                        if (UDP->flags & FD_DEBUG) {
                                DPRINT("calling disk change from set_dor\n");
                        }
#endif
                        disk_change(drive);
                }
                FDCS->dor = newdor;
                fd_outb(newdor, FD_DOR);

                unit = newdor & 0x3;
                if (!is_selected(olddor, unit) && is_selected(newdor, unit)) {
                        drive = REVDRIVE(fdc, unit);
                        UDRS->select_date = jiffies;
                }
        }
        return olddor;
}

static void twaddle(void)
{
        if (DP->select_delay)
                return;
        fd_outb(FDCS->dor & ~(0x10 << UNIT(current_drive)), FD_DOR);
        fd_outb(FDCS->dor, FD_DOR);
        DRS->select_date = jiffies;
}

/* reset all driver information about the current fdc. This is needed after
 * a reset, and after a raw command. */
static void reset_fdc_info(int mode)
{
        int drive;

        FDCS->spec1 = FDCS->spec2 = -1;
        FDCS->need_configure = 1;
        FDCS->perp_mode = 1;
        FDCS->rawcmd = 0;
        for (drive = 0; drive < N_DRIVE; drive++)
                if (FDC(drive) == fdc && (mode || UDRS->track != NEED_1_RECAL))
                        UDRS->track = NEED_2_RECAL;
}

/* selects the fdc and drive, and enables the fdc's input/dma. */
static void set_fdc(int drive)
{
        if (drive >= 0 && drive < N_DRIVE) {
                fdc = FDC(drive);
                current_drive = drive;
        }
        if (fdc != 1 && fdc != 0) {
                printk("bad fdc value\n");
                return;
        }
        set_dor(fdc, ~0, 8);
#if N_FDC > 1
        set_dor(1 - fdc, ~8, 0);
#endif
        if (FDCS->rawcmd == 2)
                reset_fdc_info(1);
        if (fd_inb(FD_STATUS) != STATUS_READY)
                FDCS->reset = 1;
}

/* locks the driver */
static int _lock_fdc(int drive, int interruptible, int line)
{
        if (!usage_count) {
                printk(KERN_ERR
                       "Trying to lock fdc while usage count=0 at line %d\n",
                       line);
                return -1;
        }

        if (test_and_set_bit(0, &fdc_busy)) {
                DECLARE_WAITQUEUE(wait, current);
                add_wait_queue(&fdc_wait, &wait);

                for (;;) {
                        set_current_state(TASK_INTERRUPTIBLE);

                        if (!test_and_set_bit(0, &fdc_busy))
                                break;

                        schedule();

                        if (!NO_SIGNAL) {
                                remove_wait_queue(&fdc_wait, &wait);
                                return -EINTR;
                        }
                }

                set_current_state(TASK_RUNNING);
                remove_wait_queue(&fdc_wait, &wait);
                flush_scheduled_work();
        }
        command_status = FD_COMMAND_NONE;

        __reschedule_timeout(drive, "lock fdc", 0);
        set_fdc(drive);
        return 0;
}

#define lock_fdc(drive,interruptible) _lock_fdc(drive,interruptible, __LINE__)

#define LOCK_FDC(drive,interruptible) \
if (lock_fdc(drive,interruptible)) return -EINTR;

/* unlocks the driver */
static inline void unlock_fdc(void)
{
        unsigned long flags;

        raw_cmd = NULL;
        if (!test_bit(0, &fdc_busy))
                DPRINT("FDC access conflict!\n");

        if (do_floppy)
                DPRINT("device interrupt still active at FDC release: %p!\n",
                       do_floppy);
        command_status = FD_COMMAND_NONE;
        spin_lock_irqsave(&floppy_lock, flags);
        del_timer(&fd_timeout);
        cont = NULL;
        clear_bit(0, &fdc_busy);
        if (elv_next_request(floppy_queue))
                do_fd_request(floppy_queue);
        spin_unlock_irqrestore(&floppy_lock, flags);
        wake_up(&fdc_wait);
}

/* switches the motor off after a given timeout */
static void motor_off_callback(unsigned long nr)
{
        unsigned char mask = ~(0x10 << UNIT(nr));

        set_dor(FDC(nr), mask, 0);
}

/* schedules motor off */
static void floppy_off(unsigned int drive)
{
        unsigned long volatile delta;
        int fdc = FDC(drive);

        if (!(FDCS->dor & (0x10 << UNIT(drive))))
                return;

        del_timer(motor_off_timer + drive);

        /* make spindle stop in a position which minimizes spinup time
         * next time */
        if (UDP->rps) {
                delta = jiffies - UDRS->first_read_date + HZ -
                    UDP->spindown_offset;
                delta = ((delta * UDP->rps) % HZ) / UDP->rps;
                motor_off_timer[drive].expires =
                    jiffies + UDP->spindown - delta;
        }
        add_timer(motor_off_timer + drive);
}

/*
 * cycle through all N_DRIVE floppy drives, for disk change testing.
 * stopping at current drive. This is done before any long operation, to
 * be sure to have up to date disk change information.
 */
static void scandrives(void)
{
        int i;
        int drive;
        int saved_drive;

        if (DP->select_delay)
                return;

        saved_drive = current_drive;
        for (i = 0; i < N_DRIVE; i++) {
                drive = (saved_drive + i + 1) % N_DRIVE;
                if (UDRS->fd_ref == 0 || UDP->select_delay != 0)
                        continue;       /* skip closed drives */
                set_fdc(drive);
                if (!(set_dor(fdc, ~3, UNIT(drive) | (0x10 << UNIT(drive))) &
                      (0x10 << UNIT(drive))))
                        /* switch the motor off again, if it was off to
                         * begin with */
                        set_dor(fdc, ~(0x10 << UNIT(drive)), 0);
        }
        set_fdc(saved_drive);
}

static void empty(void)
{
}

static DECLARE_WORK(floppy_work, NULL);

static void schedule_bh(void (*handler) (void))
{

        PREPARE_WORK(&floppy_work, (work_func_t)handler);
        schedule_work(&floppy_work);
}

static DEFINE_TIMER(fd_timer, NULL, 0, 0);

static void cancel_activity(void)
{
        unsigned long flags;

        spin_lock_irqsave(&floppy_lock, flags);
        do_floppy = NULL;
        PREPARE_WORK(&floppy_work, (work_func_t)empty);
        del_timer(&fd_timer);
        spin_unlock_irqrestore(&floppy_lock, flags);
}

/* this function makes sure that the disk stays in the drive during the
 * transfer */
static void fd_watchdog(void)
{
#ifdef DCL_DEBUG
        if (DP->flags & FD_DEBUG) {
                DPRINT("calling disk change from watchdog\n");
        }
#endif

        if (disk_change(current_drive)) {
                DPRINT("disk removed during i/o\n");
                cancel_activity();
                cont->done(0);
                reset_fdc();
        } else {
                del_timer(&fd_timer);
                fd_timer.function = (timeout_fn) fd_watchdog;
                fd_timer.expires = jiffies + HZ / 10;
                add_timer(&fd_timer);
        }
}

static void main_command_interrupt(void)
{
        del_timer(&fd_timer);
        cont->interrupt();
}

/* waits for a delay (spinup or select) to pass */
static int fd_wait_for_completion(unsigned long delay, timeout_fn function)
{
        if (FDCS->reset) {
                reset_fdc();    /* do the reset during sleep to win time
                                 * if we don't need to sleep, it's a good
                                 * occasion anyways */
                return 1;
        }

        if (time_before(jiffies, delay)) {
                del_timer(&fd_timer);
                fd_timer.function = function;
                fd_timer.expires = delay;
                add_timer(&fd_timer);
                return 1;
        }
        return 0;
}

static DEFINE_SPINLOCK(floppy_hlt_lock);
static int hlt_disabled;
static void floppy_disable_hlt(void)
{
        unsigned long flags;

        spin_lock_irqsave(&floppy_hlt_lock, flags);
        if (!hlt_disabled) {
                hlt_disabled = 1;
#ifdef HAVE_DISABLE_HLT
                disable_hlt();
#endif
        }
        spin_unlock_irqrestore(&floppy_hlt_lock, flags);
}

static void floppy_enable_hlt(void)
{
        unsigned long flags;

        spin_lock_irqsave(&floppy_hlt_lock, flags);
        if (hlt_disabled) {
                hlt_disabled = 0;
#ifdef HAVE_DISABLE_HLT
                enable_hlt();
#endif
        }
        spin_unlock_irqrestore(&floppy_hlt_lock, flags);
}

static void setup_DMA(void)
{
        unsigned long f;

#ifdef FLOPPY_SANITY_CHECK
        if (raw_cmd->length == 0) {
                int i;

                printk("zero dma transfer size:");
                for (i = 0; i < raw_cmd->cmd_count; i++)
                        printk("%x,", raw_cmd->cmd[i]);
                printk("\n");
                cont->done(0);
                FDCS->reset = 1;
                return;
        }
        if (((unsigned long)raw_cmd->kernel_data) % 512) {
                printk("non aligned address: %p\n", raw_cmd->kernel_data);
                cont->done(0);
                FDCS->reset = 1;
                return;
        }
#endif
        f = claim_dma_lock();
        fd_disable_dma();
#ifdef fd_dma_setup
        if (fd_dma_setup(raw_cmd->kernel_data, raw_cmd->length,
                         (raw_cmd->flags & FD_RAW_READ) ?
                         DMA_MODE_READ : DMA_MODE_WRITE, FDCS->address) < 0) {
                release_dma_lock(f);
                cont->done(0);
                FDCS->reset = 1;
                return;
        }
        release_dma_lock(f);
#else
        fd_clear_dma_ff();
        fd_cacheflush(raw_cmd->kernel_data, raw_cmd->length);
        fd_set_dma_mode((raw_cmd->flags & FD_RAW_READ) ?
                        DMA_MODE_READ : DMA_MODE_WRITE);
        fd_set_dma_addr(raw_cmd->kernel_data);
        fd_set_dma_count(raw_cmd->length);
        virtual_dma_port = FDCS->address;
        fd_enable_dma();
        release_dma_lock(f);
#endif
        floppy_disable_hlt();
}

static void show_floppy(void);

/* waits until the fdc becomes ready */
static int wait_til_ready(void)
{
        int status;
        int counter;

        if (FDCS->reset)
                return -1;
        for (counter = 0; counter < 10000; counter++) {
                status = fd_inb(FD_STATUS);
                if (status & STATUS_READY)
                        return status;
        }
        if (!initialising) {
                DPRINT("Getstatus times out (%x) on fdc %d\n", status, fdc);
                show_floppy();
        }
        FDCS->reset = 1;
        return -1;
}

/* sends a command byte to the fdc */
static int output_byte(char byte)
{
        int status;

        if ((status = wait_til_ready()) < 0)
                return -1;
        if ((status & (STATUS_READY | STATUS_DIR | STATUS_DMA)) == STATUS_READY) {
                fd_outb(byte, FD_DATA);
#ifdef FLOPPY_SANITY_CHECK
                output_log[output_log_pos].data = byte;
                output_log[output_log_pos].status = status;
                output_log[output_log_pos].jiffies = jiffies;
                output_log_pos = (output_log_pos + 1) % OLOGSIZE;
#endif
                return 0;
        }
        FDCS->reset = 1;
        if (!initialising) {
                DPRINT("Unable to send byte %x to FDC. Fdc=%x Status=%x\n",
                       byte, fdc, status);
                show_floppy();
        }
        return -1;
}

#define LAST_OUT(x) if (output_byte(x)<0){ reset_fdc();return;}

/* gets the response from the fdc */
static int result(void)
{
        int i;
        int status = 0;

        for (i = 0; i < MAX_REPLIES; i++) {
                if ((status = wait_til_ready()) < 0)
                        break;
                status &= STATUS_DIR | STATUS_READY | STATUS_BUSY | STATUS_DMA;
                if ((status & ~STATUS_BUSY) == STATUS_READY) {
#ifdef FLOPPY_SANITY_CHECK
                        resultjiffies = jiffies;
                        resultsize = i;
#endif
                        return i;
                }
                if (status == (STATUS_DIR | STATUS_READY | STATUS_BUSY))
                        reply_buffer[i] = fd_inb(FD_DATA);
                else
                        break;
        }
        if (!initialising) {
                DPRINT
                    ("get result error. Fdc=%d Last status=%x Read bytes=%d\n",
                     fdc, status, i);
                show_floppy();
        }
        FDCS->reset = 1;
        return -1;
}

#define MORE_OUTPUT -2
/* does the fdc need more output? */
static int need_more_output(void)
{
        int status;

        if ((status = wait_til_ready()) < 0)
                return -1;
        if ((status & (STATUS_READY | STATUS_DIR | STATUS_DMA)) == STATUS_READY)
                return MORE_OUTPUT;
        return result();
}

/* Set perpendicular mode as required, based on data rate, if supported.
 * 82077 Now tested. 1Mbps data rate only possible with 82077-1.
 */
static inline void perpendicular_mode(void)
{
        unsigned char perp_mode;

        if (raw_cmd->rate & 0x40) {
                switch (raw_cmd->rate & 3) {
                case 0:
                        perp_mode = 2;
                        break;
                case 3:
                        perp_mode = 3;
                        break;
                default:
                        DPRINT("Invalid data rate for perpendicular mode!\n");
                        cont->done(0);
                        FDCS->reset = 1;        /* convenient way to return to
                                                 * redo without to much hassle (deep
                                                 * stack et al. */
                        return;
                }
        } else
                perp_mode = 0;

        if (FDCS->perp_mode == perp_mode)
                return;
        if (FDCS->version >= FDC_82077_ORIG) {
                output_byte(FD_PERPENDICULAR);
                output_byte(perp_mode);
                FDCS->perp_mode = perp_mode;
        } else if (perp_mode) {
                DPRINT("perpendicular mode not supported by this FDC.\n");
        }
}                               /* perpendicular_mode */

static int fifo_depth = 0xa;
static int no_fifo;

static int fdc_configure(void)
{
        /* Turn on FIFO */
        output_byte(FD_CONFIGURE);
        if (need_more_output() != MORE_OUTPUT)
                return 0;
        output_byte(0);
        output_byte(0x10 | (no_fifo & 0x20) | (fifo_depth & 0xf));
        output_byte(0);         /* pre-compensation from track
                                   0 upwards */
        return 1;
}

#define NOMINAL_DTR 500

/* Issue a "SPECIFY" command to set the step rate time, head unload time,
 * head load time, and DMA disable flag to values needed by floppy.
 *
 * The value "dtr" is the data transfer rate in Kbps.  It is needed
 * to account for the data rate-based scaling done by the 82072 and 82077
 * FDC types.  This parameter is ignored for other types of FDCs (i.e.
 * 8272a).
 *
 * Note that changing the data transfer rate has a (probably deleterious)
 * effect on the parameters subject to scaling for 82072/82077 FDCs, so
 * fdc_specify is called again after each data transfer rate
 * change.
 *
 * srt: 1000 to 16000 in microseconds
 * hut: 16 to 240 milliseconds
 * hlt: 2 to 254 milliseconds
 *
 * These values are rounded up to the next highest available delay time.
 */
static void fdc_specify(void)
{
        unsigned char spec1;
        unsigned char spec2;
        unsigned long srt;
        unsigned long hlt;
        unsigned long hut;
        unsigned long dtr = NOMINAL_DTR;
        unsigned long scale_dtr = NOMINAL_DTR;
        int hlt_max_code = 0x7f;
        int hut_max_code = 0xf;

        if (FDCS->need_configure && FDCS->version >= FDC_82072A) {
                fdc_configure();
                FDCS->need_configure = 0;
        }

        switch (raw_cmd->rate & 0x03) {
        case 3:
                dtr = 1000;
                break;
        case 1:
                dtr = 300;
                if (FDCS->version >= FDC_82078) {
                        /* chose the default rate table, not the one
                         * where 1 = 2 Mbps */
                        output_byte(FD_DRIVESPEC);
                        if (need_more_output() == MORE_OUTPUT) {
                                output_byte(UNIT(current_drive));
                                output_byte(0xc0);
                        }
                }
                break;
        case 2:
                dtr = 250;
                break;
        }

        if (FDCS->version >= FDC_82072) {
                scale_dtr = dtr;
                hlt_max_code = 0x00;    /* 0==256msec*dtr0/dtr (not linear!) */
                hut_max_code = 0x0;     /* 0==256msec*dtr0/dtr (not linear!) */
        }

        /* Convert step rate from microseconds to milliseconds and 4 bits */
        srt = 16 - (DP->srt * scale_dtr / 1000 + NOMINAL_DTR - 1) / NOMINAL_DTR;
        if (slow_floppy) {
                srt = srt / 4;
        }
        SUPBOUND(srt, 0xf);
        INFBOUND(srt, 0);

        hlt = (DP->hlt * scale_dtr / 2 + NOMINAL_DTR - 1) / NOMINAL_DTR;
        if (hlt < 0x01)
                hlt = 0x01;
        else if (hlt > 0x7f)
                hlt = hlt_max_code;

        hut = (DP->hut * scale_dtr / 16 + NOMINAL_DTR - 1) / NOMINAL_DTR;
        if (hut < 0x1)
                hut = 0x1;
        else if (hut > 0xf)
                hut = hut_max_code;

        spec1 = (srt << 4) | hut;
        spec2 = (hlt << 1) | (use_virtual_dma & 1);

        /* If these parameters did not change, just return with success */
        if (FDCS->spec1 != spec1 || FDCS->spec2 != spec2) {
                /* Go ahead and set spec1 and spec2 */
                output_byte(FD_SPECIFY);
                output_byte(FDCS->spec1 = spec1);
                output_byte(FDCS->spec2 = spec2);
        }
}                               /* fdc_specify */

/* Set the FDC's data transfer rate on behalf of the specified drive.
 * NOTE: with 82072/82077 FDCs, changing the data rate requires a reissue
 * of the specify command (i.e. using the fdc_specify function).
 */
static int fdc_dtr(void)
{
        /* If data rate not already set to desired value, set it. */
        if ((raw_cmd->rate & 3) == FDCS->dtr)
                return 0;

        /* Set dtr */
        fd_outb(raw_cmd->rate & 3, FD_DCR);

        /* TODO: some FDC/drive combinations (C&T 82C711 with TEAC 1.2MB)
         * need a stabilization period of several milliseconds to be
         * enforced after data rate changes before R/W operations.
         * Pause 5 msec to avoid trouble. (Needs to be 2 jiffies)
         */
        FDCS->dtr = raw_cmd->rate & 3;
        return (fd_wait_for_completion(jiffies + 2UL * HZ / 100,
                                       (timeout_fn) floppy_ready));
}                               /* fdc_dtr */

static void tell_sector(void)
{
        printk(": track %d, head %d, sector %d, size %d",
               R_TRACK, R_HEAD, R_SECTOR, R_SIZECODE);
}                               /* tell_sector */

/*
 * OK, this error interpreting routine is called after a
 * DMA read/write has succeeded
 * or failed, so we check the results, and copy any buffers.
 * hhb: Added better error reporting.
 * ak: Made this into a separate routine.
 */
static int interpret_errors(void)
{
        char bad;

        if (inr != 7) {
                DPRINT("-- FDC reply error");
                FDCS->reset = 1;
                return 1;
        }

        /* check IC to find cause of interrupt */
        switch (ST0 & ST0_INTR) {
        case 0x40:              /* error occurred during command execution */
                if (ST1 & ST1_EOC)
                        return 0;       /* occurs with pseudo-DMA */
                bad = 1;
                if (ST1 & ST1_WP) {
                        DPRINT("Drive is write protected\n");
                        CLEARF(FD_DISK_WRITABLE);
                        cont->done(0);
                        bad = 2;
                } else if (ST1 & ST1_ND) {
                        SETF(FD_NEED_TWADDLE);
                } else if (ST1 & ST1_OR) {
                        if (DP->flags & FTD_MSG)
                                DPRINT("Over/Underrun - retrying\n");
                        bad = 0;
                } else if (*errors >= DP->max_errors.reporting) {
                        DPRINT("");
                        if (ST0 & ST0_ECE) {
                                printk("Recalibrate failed!");
                        } else if (ST2 & ST2_CRC) {
                                printk("data CRC error");
                                tell_sector();
                        } else if (ST1 & ST1_CRC) {
                                printk("CRC error");
                                tell_sector();
                        } else if ((ST1 & (ST1_MAM | ST1_ND))
                                   || (ST2 & ST2_MAM)) {
                                if (!probing) {
                                        printk("sector not found");
                                        tell_sector();
                                } else
                                        printk("probe failed...");
                        } else if (ST2 & ST2_WC) {      /* seek error */
                                printk("wrong cylinder");
                        } else if (ST2 & ST2_BC) {      /* cylinder marked as bad */
                                printk("bad cylinder");
                        } else {
                                printk
                                    ("unknown error. ST[0..2] are: 0x%x 0x%x 0x%x",
                                     ST0, ST1, ST2);
                                tell_sector();
                        }
                        printk("\n");
                }
                if (ST2 & ST2_WC || ST2 & ST2_BC)
                        /* wrong cylinder => recal */
                        DRS->track = NEED_2_RECAL;
                return bad;
        case 0x80:              /* invalid command given */
                DPRINT("Invalid FDC command given!\n");
                cont->done(0);
                return 2;
        case 0xc0:
                DPRINT("Abnormal termination caused by polling\n");
                cont->error();
                return 2;
        default:                /* (0) Normal command termination */
                return 0;
        }
}

/*
 * This routine is called when everything should be correctly set up
 * for the transfer (i.e. floppy motor is on, the correct floppy is
 * selected, and the head is sitting on the right track).
 */
static void setup_rw_floppy(void)
{
        int i;
        int r;
        int flags;
        int dflags;
        unsigned long ready_date;
        timeout_fn function;

        flags = raw_cmd->flags;
        if (flags & (FD_RAW_READ | FD_RAW_WRITE))
                flags |= FD_RAW_INTR;

        if ((flags & FD_RAW_SPIN) && !(flags & FD_RAW_NO_MOTOR)) {
                ready_date = DRS->spinup_date + DP->spinup;
                /* If spinup will take a long time, rerun scandrives
                 * again just before spinup completion. Beware that
                 * after scandrives, we must again wait for selection.
                 */
                if (time_after(ready_date, jiffies + DP->select_delay)) {
                        ready_date -= DP->select_delay;
                        function = (timeout_fn) floppy_start;
                } else
                        function = (timeout_fn) setup_rw_floppy;

                /* wait until the floppy is spinning fast enough */
                if (fd_wait_for_completion(ready_date, function))
                        return;
        }
        dflags = DRS->flags;

        if ((flags & FD_RAW_READ) || (flags & FD_RAW_WRITE))
                setup_DMA();

        if (flags & FD_RAW_INTR)
                do_floppy = main_command_interrupt;

        r = 0;
        for (i = 0; i < raw_cmd->cmd_count; i++)
                r |= output_byte(raw_cmd->cmd[i]);

        debugt("rw_command: ");

        if (r) {
                cont->error();
                reset_fdc();
                return;
        }

        if (!(flags & FD_RAW_INTR)) {
                inr = result();
                cont->interrupt();
        } else if (flags & FD_RAW_NEED_DISK)
                fd_watchdog();
}

static int blind_seek;

/*
 * This is the routine called after every seek (or recalibrate) interrupt
 * from the floppy controller.
 */
static void seek_interrupt(void)
{
        debugt("seek interrupt:");
        if (inr != 2 || (ST0 & 0xF8) != 0x20) {
                DPRINT("seek failed\n");
                DRS->track = NEED_2_RECAL;
                cont->error();
                cont->redo();
                return;
        }
        if (DRS->track >= 0 && DRS->track != ST1 && !blind_seek) {
#ifdef DCL_DEBUG
                if (DP->flags & FD_DEBUG) {
                        DPRINT
                            ("clearing NEWCHANGE flag because of effective seek\n");
                        DPRINT("jiffies=%lu\n", jiffies);
                }
#endif
                CLEARF(FD_DISK_NEWCHANGE);      /* effective seek */
                DRS->select_date = jiffies;
        }
        DRS->track = ST1;
        floppy_ready();
}

static void check_wp(void)
{
        if (TESTF(FD_VERIFY)) {
                /* check write protection */
                output_byte(FD_GETSTATUS);
                output_byte(UNIT(current_drive));
                if (result() != 1) {
                        FDCS->reset = 1;
                        return;
                }
                CLEARF(FD_VERIFY);
                CLEARF(FD_NEED_TWADDLE);
#ifdef DCL_DEBUG
                if (DP->flags & FD_DEBUG) {
                        DPRINT("checking whether disk is write protected\n");
                        DPRINT("wp=%x\n", ST3 & 0x40);
                }
#endif
                if (!(ST3 & 0x40))
                        SETF(FD_DISK_WRITABLE);
                else
                        CLEARF(FD_DISK_WRITABLE);
        }
}

static void seek_floppy(void)
{
        int track;

        blind_seek = 0;

#ifdef DCL_DEBUG
        if (DP->flags & FD_DEBUG) {
                DPRINT("calling disk change from seek\n");
        }
#endif

        if (!TESTF(FD_DISK_NEWCHANGE) &&
            disk_change(current_drive) && (raw_cmd->flags & FD_RAW_NEED_DISK)) {
                /* the media changed flag should be cleared after the seek.
                 * If it isn't, this means that there is really no disk in
                 * the drive.
                 */
                SETF(FD_DISK_CHANGED);
                cont->done(0);
                cont->redo();
                return;
        }
        if (DRS->track <= NEED_1_RECAL) {
                recalibrate_floppy();
                return;
        } else if (TESTF(FD_DISK_NEWCHANGE) &&
                   (raw_cmd->flags & FD_RAW_NEED_DISK) &&
                   (DRS->track <= NO_TRACK || DRS->track == raw_cmd->track)) {
                /* we seek to clear the media-changed condition. Does anybody
                 * know a more elegant way, which works on all drives? */
                if (raw_cmd->track)
                        track = raw_cmd->track - 1;
                else {
                        if (DP->flags & FD_SILENT_DCL_CLEAR) {
                                set_dor(fdc, ~(0x10 << UNIT(current_drive)), 0);
                                blind_seek = 1;
                                raw_cmd->flags |= FD_RAW_NEED_SEEK;
                        }
                        track = 1;
                }
        } else {
                check_wp();
                if (raw_cmd->track != DRS->track &&
                    (raw_cmd->flags & FD_RAW_NEED_SEEK))
                        track = raw_cmd->track;
                else {
                        setup_rw_floppy();
                        return;
                }
        }

        do_floppy = seek_interrupt;
        output_byte(FD_SEEK);
        output_byte(UNIT(current_drive));
        LAST_OUT(track);
        debugt("seek command:");
}

static void recal_interrupt(void)
{
        debugt("recal interrupt:");
        if (inr != 2)
                FDCS->reset = 1;
        else if (ST0 & ST0_ECE) {
                switch (DRS->track) {
                case NEED_1_RECAL:
                        debugt("recal interrupt need 1 recal:");
                        /* after a second recalibrate, we still haven't
                         * reached track 0. Probably no drive. Raise an
                         * error, as failing immediately might upset
                         * computers possessed by the Devil :-) */
                        cont->error();
                        cont->redo();
                        return;
                case NEED_2_RECAL:
                        debugt("recal interrupt need 2 recal:");
                        /* If we already did a recalibrate,
                         * and we are not at track 0, this
                         * means we have moved. (The only way
                         * not to move at recalibration is to
                         * be already at track 0.) Clear the
                         * new change flag */
#ifdef DCL_DEBUG
                        if (DP->flags & FD_DEBUG) {
                                DPRINT
                                    ("clearing NEWCHANGE flag because of second recalibrate\n");
                        }
#endif

                        CLEARF(FD_DISK_NEWCHANGE);
                        DRS->select_date = jiffies;
                        /* fall through */
                default:
                        debugt("recal interrupt default:");
                        /* Recalibrate moves the head by at
                         * most 80 steps. If after one
                         * recalibrate we don't have reached
                         * track 0, this might mean that we
                         * started beyond track 80.  Try
                         * again.  */
                        DRS->track = NEED_1_RECAL;
                        break;
                }
        } else
                DRS->track = ST1;
        floppy_ready();
}

static void print_result(char *message, int inr)
{
        int i;

        DPRINT("%s ", message);
        if (inr >= 0)
                for (i = 0; i < inr; i++)
                        printk("repl[%d]=%x ", i, reply_buffer[i]);
        printk("\n");
}

/* interrupt handler. Note that this can be called externally on the Sparc */
irqreturn_t floppy_interrupt(int irq, void *dev_id)
{
        int do_print;
        unsigned long f;
        void (*handler)(void) = do_floppy;

        lasthandler = handler;
        interruptjiffies = jiffies;

        f = claim_dma_lock();
        fd_disable_dma();
        release_dma_lock(f);

        floppy_enable_hlt();
        do_floppy = NULL;
        if (fdc >= N_FDC || FDCS->address == -1) {
                /* we don't even know which FDC is the culprit */
                printk("DOR0=%x\n", fdc_state[0].dor);
                printk("floppy interrupt on bizarre fdc %d\n", fdc);
                printk("handler=%p\n", handler);
                is_alive("bizarre fdc");
                return IRQ_NONE;
        }

        FDCS->reset = 0;
        /* We have to clear the reset flag here, because apparently on boxes
         * with level triggered interrupts (PS/2, Sparc, ...), it is needed to
         * emit SENSEI's to clear the interrupt line. And FDCS->reset blocks the
         * emission of the SENSEI's.
         * It is OK to emit floppy commands because we are in an interrupt
         * handler here, and thus we have to fear no interference of other
         * activity.
         */

        do_print = !handler && print_unex && !initialising;

        inr = result();
        if (do_print)
                print_result("unexpected interrupt", inr);
        if (inr == 0) {
                int max_sensei = 4;
                do {
                        output_byte(FD_SENSEI);
                        inr = result();
                        if (do_print)
                                print_result("sensei", inr);
                        max_sensei--;
                } while ((ST0 & 0x83) != UNIT(current_drive) && inr == 2
                         && max_sensei);
        }
        if (!handler) {
                FDCS->reset = 1;
                return IRQ_NONE;
        }
        schedule_bh(handler);
        is_alive("normal interrupt end");

        /* FIXME! Was it really for us? */
        return IRQ_HANDLED;
}

static void recalibrate_floppy(void)
{
        debugt("recalibrate floppy:");
        do_floppy = recal_interrupt;
        output_byte(FD_RECALIBRATE);
        LAST_OUT(UNIT(current_drive));
}

/*
 * Must do 4 FD_SENSEIs after reset because of ``drive polling''.
 */
static void reset_interrupt(void)
{
        debugt("reset interrupt:");
        result();               /* get the status ready for set_fdc */
        if (FDCS->reset) {
                printk("reset set in interrupt, calling %p\n", cont->error);
                cont->error();  /* a reset just after a reset. BAD! */
        }
        cont->redo();
}

/*
 * reset is done by pulling bit 2 of DOR low for a while (old FDCs),
 * or by setting the self clearing bit 7 of STATUS (newer FDCs)
 */
static void reset_fdc(void)
{
        unsigned long flags;

        do_floppy = reset_interrupt;
        FDCS->reset = 0;
        reset_fdc_info(0);

        /* Pseudo-DMA may intercept 'reset finished' interrupt.  */
        /* Irrelevant for systems with true DMA (i386).          */

        flags = claim_dma_lock();
        fd_disable_dma();
        release_dma_lock(flags);

        if (FDCS->version >= FDC_82072A)
                fd_outb(0x80 | (FDCS->dtr & 3), FD_STATUS);
        else {
                fd_outb(FDCS->dor & ~0x04, FD_DOR);
                udelay(FD_RESET_DELAY);
                fd_outb(FDCS->dor, FD_DOR);
        }
}

static void show_floppy(void)
{
        int i;

        printk("\n");
        printk("floppy driver state\n");
        printk("-------------------\n");
        printk("now=%lu last interrupt=%lu diff=%lu last called handler=%p\n",
               jiffies, interruptjiffies, jiffies - interruptjiffies,
               lasthandler);

#ifdef FLOPPY_SANITY_CHECK
        printk("timeout_message=%s\n", timeout_message);
        printk("last output bytes:\n");
        for (i = 0; i < OLOGSIZE; i++)
                printk("%2x %2x %lu\n",
                       output_log[(i + output_log_pos) % OLOGSIZE].data,
                       output_log[(i + output_log_pos) % OLOGSIZE].status,
                       output_log[(i + output_log_pos) % OLOGSIZE].jiffies);
        printk("last result at %lu\n", resultjiffies);
        printk("last redo_fd_request at %lu\n", lastredo);
        for (i = 0; i < resultsize; i++) {
                printk("%2x ", reply_buffer[i]);
        }
        printk("\n");
#endif

        printk("status=%x\n", fd_inb(FD_STATUS));
        printk("fdc_busy=%lu\n", fdc_busy);
        if (do_floppy)
                printk("do_floppy=%p\n", do_floppy);
        if (work_pending(&floppy_work))
                printk("floppy_work.func=%p\n", floppy_work.func);
        if (timer_pending(&fd_timer))
                printk("fd_timer.function=%p\n", fd_timer.function);
        if (timer_pending(&fd_timeout)) {
                printk("timer_function=%p\n", fd_timeout.function);
                printk("expires=%lu\n", fd_timeout.expires - jiffies);
                printk("now=%lu\n", jiffies);
        }
        printk("cont=%p\n", cont);
        printk("current_req=%p\n", current_req);
        printk("command_status=%d\n", command_status);
        printk("\n");
}

static void floppy_shutdown(unsigned long data)
{
        unsigned long flags;

        if (!initialising)
                show_floppy();
        cancel_activity();

        floppy_enable_hlt();

        flags = claim_dma_lock();
        fd_disable_dma();
        release_dma_lock(flags);

        /* avoid dma going to a random drive after shutdown */

        if (!initialising)
                DPRINT("floppy timeout called\n");
        FDCS->reset = 1;
        if (cont) {
                cont->done(0);
                cont->redo();   /* this will recall reset when needed */
        } else {
                printk("no cont in shutdown!\n");
                process_fd_request();
        }
        is_alive("floppy shutdown");
}

/* start motor, check media-changed condition and write protection */
static int start_motor(void (*function)(void))
{
        int mask;
        int data;

        mask = 0xfc;
        data = UNIT(current_drive);
        if (!(raw_cmd->flags & FD_RAW_NO_MOTOR)) {
                if (!(FDCS->dor & (0x10 << UNIT(current_drive)))) {
                        set_debugt();
                        /* no read since this drive is running */
                        DRS->first_read_date = 0;
                        /* note motor start time if motor is not yet running */
                        DRS->spinup_date = jiffies;
                        data |= (0x10 << UNIT(current_drive));
                }
        } else if (FDCS->dor & (0x10 << UNIT(current_drive)))
                mask &= ~(0x10 << UNIT(current_drive));

        /* starts motor and selects floppy */
        del_timer(motor_off_timer + current_drive);
        set_dor(fdc, mask, data);

        /* wait_for_completion also schedules reset if needed. */
        return (fd_wait_for_completion(DRS->select_date + DP->select_delay,
                                       (timeout_fn) function));
}

static void floppy_ready(void)
{
        CHECK_RESET;
        if (start_motor(floppy_ready))
                return;
        if (fdc_dtr())
                return;

#ifdef DCL_DEBUG
        if (DP->flags & FD_DEBUG) {
                DPRINT("calling disk change from floppy_ready\n");
        }
#endif
        if (!(raw_cmd->flags & FD_RAW_NO_MOTOR) &&
            disk_change(current_drive) && !DP->select_delay)
                twaddle();      /* this clears the dcl on certain drive/controller
                                 * combinations */

#ifdef fd_chose_dma_mode
        if ((raw_cmd->flags & FD_RAW_READ) || (raw_cmd->flags & FD_RAW_WRITE)) {
                unsigned long flags = claim_dma_lock();
                fd_chose_dma_mode(raw_cmd->kernel_data, raw_cmd->length);
                release_dma_lock(flags);
        }
#endif

        if (raw_cmd->flags & (FD_RAW_NEED_SEEK | FD_RAW_NEED_DISK)) {
                perpendicular_mode();
                fdc_specify();  /* must be done here because of hut, hlt ... */
                seek_floppy();
        } else {
                if ((raw_cmd->flags & FD_RAW_READ) ||
                    (raw_cmd->flags & FD_RAW_WRITE))
                        fdc_specify();
                setup_rw_floppy();
        }
}

static void floppy_start(void)
{
        reschedule_timeout(current_reqD, "floppy start", 0);

        scandrives();
#ifdef DCL_DEBUG
        if (DP->flags & FD_DEBUG) {
                DPRINT("setting NEWCHANGE in floppy_start\n");
        }