/*
 *  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.
 */

#undef  FLOPPY_SILENT_DCL_CLEAR

#define REALLY_SLOW_IO

#define DEBUGT 2

#define DPRINT(format, args...) \
        pr_info("floppy%d: " format, current_drive, ##args)

#define DCL_DEBUG               /* debug disk change line */
#ifdef DCL_DEBUG
#define debug_dcl(test, fmt, args...) \
        do { if ((test) & FD_DEBUG) DPRINT(fmt, ##args); } while (0)
#else
#define debug_dcl(test, fmt, args...) \
        do { if (0) DPRINT(fmt, ##args); } while (0)
#endif

/* 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>
#include <linux/io.h>
#include <linux/uaccess.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 DEFINE_MUTEX(floppy_mutex);
static int slow_floppy;

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

#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 void do_fd_request(struct request_queue *q);
static int set_next_request(void);

#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 */
        pr_info("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 bool initialized;

#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 UDP     (&drive_params[drive])
#define UDRS    (&drive_state[drive])
#define UDRWE   (&write_errors[drive])
#define UFDCS   (&fdc_state[FDC(drive)])

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

/* 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;
static int fdc_queue;

/*
 * 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'.
 *
 * Bits 2 through 9 of 'stretch' tell the number of the first sector.
 * The LSB (bit 2) is flipped. For most disks, the first sector
 * is 1 (represented by 0x00<<2).  For some CP/M and music sampler
 * disks (such as Ensoniq EPS 16plus) it is 0 (represented as 0x01<<2).
 * For Amstrad CPC disks it is 0xC1 (represented as 0xC0<<2).
 *
 * 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);

/* 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 const 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.
 */
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 atomic_t usage_count = ATOMIC_INIT(0);

/* 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 */

static inline bool drive_no_geom(int drive)
{
        return !current_type[drive] && !ITYPE(UDRS->fd_device);
}

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

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

static const char *timeout_message;

static void is_alive(const char *func, 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("%s: timeout handler died.  %s\n", func, message);
        }
}

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

#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;

#define current_reqD -1
#define MAXTIMEOUT -2

static void __reschedule_timeout(int drive, const char *message)
{
        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 %s\n", message);
        timeout_message = message;
}

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

        spin_lock_irqsave(&floppy_lock, flags);
        __reschedule_timeout(drive, message);
        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);

        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);
        }

        debug_dcl(UDP->flags,
                  "checking disk change line for drive %d\n", drive);
        debug_dcl(UDP->flags, "jiffies=%lu\n", jiffies);
        debug_dcl(UDP->flags, "disk change line=%x\n", fd_inb(FD_DIR) & 0x80);
        debug_dcl(UDP->flags, "flags=%lx\n", UDRS->flags);

        if (UDP->flags & FD_BROKEN_DCL)
                return test_bit(FD_DISK_CHANGED_BIT, &UDRS->flags);
        if ((fd_inb(FD_DIR) ^ UDP->flags) & 0x80) {
                set_bit(FD_VERIFY_BIT, &UDRS->flags);
                                        /* verify write protection */

                if (UDRS->maxblock)     /* mark it changed */
                        set_bit(FD_DISK_CHANGED_BIT, &UDRS->flags);

                /* 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;
                clear_bit(FD_DISK_NEWCHANGE_BIT, &UDRS->flags);
        }
        return 0;
}

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

static bool is_ready_state(int status)
{
        int state = status & (STATUS_READY | STATUS_DIR | STATUS_DMA);
        return state == STATUS_READY;
}

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);
                        debug_dcl(UDP->flags,
                                  "calling disk change from set_dor\n");
                        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) {
                pr_info("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, bool interruptible)
{
        if (WARN(atomic_read(&usage_count) == 0,
                 "Trying to lock fdc while usage count=0\n"))
                return -1;

        if (wait_event_interruptible(fdc_wait, !test_and_set_bit(0, &fdc_busy)))
                return -EINTR;

        command_status = FD_COMMAND_NONE;

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

/* unlocks the driver */
static 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: %pf!\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 (current_req || set_next_request())
                do_fd_request(current_req->q);
        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)
{
        debug_dcl(DP->flags, "calling disk change from watchdog\n");

        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;

        WARN_ONCE(1, "floppy_disable_hlt() scheduled for removal in 2012");
        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;

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

                pr_info("zero dma transfer size:");
                for (i = 0; i < raw_cmd->cmd_count; i++)
                        pr_cont("%x,", raw_cmd->cmd[i]);
                pr_cont("\n");
                cont->done(0);
                FDCS->reset = 1;
                return;
        }
        if (((unsigned long)raw_cmd->kernel_data) % 512) {
                pr_info("non aligned address: %p\n", raw_cmd->kernel_data);
                cont->done(0);
                FDCS->reset = 1;
                return;
        }
        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 (initialized) {
                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 = wait_til_ready();

        if (status < 0)
                return -1;

        if (is_ready_state(status)) {
                fd_outb(byte, FD_DATA);
                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;
                return 0;
        }
        FDCS->reset = 1;
        if (initialized) {
                DPRINT("Unable to send byte %x to FDC. Fdc=%x Status=%x\n",
                       byte, fdc, status);
                show_floppy();
        }
        return -1;
}

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

        for (i = 0; i < MAX_REPLIES; i++) {
                status = wait_til_ready();
                if (status < 0)
                        break;
                status &= STATUS_DIR | STATUS_READY | STATUS_BUSY | STATUS_DMA;
                if ((status & ~STATUS_BUSY) == STATUS_READY) {
                        resultjiffies = jiffies;
                        resultsize = i;
                        return i;
                }
                if (status == (STATUS_DIR | STATUS_READY | STATUS_BUSY))
                        reply_buffer[i] = fd_inb(FD_DATA);
                else
                        break;
        }
        if (initialized) {
                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 = wait_til_ready();

        if (status < 0)
                return -1;

        if (is_ready_state(status))
                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 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 too 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 - DIV_ROUND_UP(DP->srt * scale_dtr / 1000, NOMINAL_DTR);
        if (slow_floppy)
                srt = srt / 4;

        SUPBOUND(srt, 0xf);
        INFBOUND(srt, 0);

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

        hut = DIV_ROUND_UP(DP->hut * scale_dtr / 16, 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)
{
        pr_cont(": track %d, head %d, sector %d, size %d",
                R_TRACK, R_HEAD, R_SECTOR, R_SIZECODE);
}                               /* tell_sector */

static void print_errors(void)
{
        DPRINT("");
        if (ST0 & ST0_ECE) {
                pr_cont("Recalibrate failed!");
        } else if (ST2 & ST2_CRC) {
                pr_cont("data CRC error");
                tell_sector();
        } else if (ST1 & ST1_CRC) {
                pr_cont("CRC error");
                tell_sector();
        } else if ((ST1 & (ST1_MAM | ST1_ND)) ||
                   (ST2 & ST2_MAM)) {
                if (!probing) {
                        pr_cont("sector not found");
                        tell_sector();
                } else
                        pr_cont("probe failed...");
        } else if (ST2 & ST2_WC) {      /* seek error */
                pr_cont("wrong cylinder");
        } else if (ST2 & ST2_BC) {      /* cylinder marked as bad */
                pr_cont("bad cylinder");
        } else {
                pr_cont("unknown error. ST[0..2] are: 0x%x 0x%x 0x%x",
                        ST0, ST1, ST2);
                tell_sector();
        }
        pr_cont("\n");
}

/*
 * 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\n");
                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");
                        clear_bit(FD_DISK_WRITABLE_BIT, &DRS->flags);
                        cont->done(0);
                        bad = 2;
                } else if (ST1 & ST1_ND) {
                        set_bit(FD_NEED_TWADDLE_BIT, &DRS->flags);
                } else if (ST1 & ST1_OR) {
                        if (DP->flags & FTD_MSG)
                                DPRINT("Over/Underrun - retrying\n");
                        bad = 0;
                } else if (*errors >= DP->max_errors.reporting) {
                        print_errors();
                }
                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(__func__, "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(__func__, "");
        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) {
                debug_dcl(DP->flags,
                          "clearing NEWCHANGE flag because of effective seek\n");
                debug_dcl(DP->flags, "jiffies=%lu\n", jiffies);
                clear_bit(FD_DISK_NEWCHANGE_BIT, &DRS->flags);
                                        /* effective seek */
                DRS->select_date = jiffies;
        }
        DRS->track = ST1;
        floppy_ready();
}

static void check_wp(void)
{
        if (test_bit(FD_VERIFY_BIT, &DRS->flags)) {
                                        /* check write protection */
                output_byte(FD_GETSTATUS);
                output_byte(UNIT(current_drive));
                if (result() != 1) {
                        FDCS->reset = 1;
                        return;
                }
                clear_bit(FD_VERIFY_BIT, &DRS->flags);
                clear_bit(FD_NEED_TWADDLE_BIT, &DRS->flags);
                debug_dcl(DP->flags,
                          "checking whether disk is write protected\n");
                debug_dcl(DP->flags, "wp=%x\n", ST3 & 0x40);
                if (!(ST3 & 0x40))
                        set_bit(FD_DISK_WRITABLE_BIT, &DRS->flags);
                else
                        clear_bit(FD_DISK_WRITABLE_BIT, &DRS->flags);
        }
}

static void seek_floppy(void)
{
        int track;

        blind_seek = 0;

        debug_dcl(DP->flags, "calling disk change from %s\n", __func__);

        if (!test_bit(FD_DISK_NEWCHANGE_BIT, &DRS->flags) &&
            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.
                 */
                set_bit(FD_DISK_CHANGED_BIT, &DRS->flags);
                cont->done(0);
                cont->redo();
                return;
        }
        if (DRS->track <= NEED_1_RECAL) {
                recalibrate_floppy();
                return;
        } else if (test_bit(FD_DISK_NEWCHANGE_BIT, &DRS->flags) &&
                   (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));
        if (output_byte(track) < 0) {
                reset_fdc();
                return;
        }
        debugt(__func__, "");
}

static void recal_interrupt(void)
{
        debugt(__func__, "");
        if (inr != 2)
                FDCS->reset = 1;
        else if (ST0 & ST0_ECE) {
                switch (DRS->track) {
                case NEED_1_RECAL:
                        debugt(__func__, "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(__func__, "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 */
                        debug_dcl(DP->flags,
                                  "clearing NEWCHANGE flag because of second recalibrate\n");

                        clear_bit(FD_DISK_NEWCHANGE_BIT, &DRS->flags);
                        DRS->select_date = jiffies;
                        /* fall through */
                default:
                        debugt(__func__, "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++)
                        pr_cont("repl[%d]=%x ", i, reply_buffer[i]);
        pr_cont("\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 */
                pr_info("DOR0=%x\n", fdc_state[0].dor);
                pr_info("floppy interrupt on bizarre fdc %d\n", fdc);
                pr_info("handler=%pf\n", handler);
                is_alive(__func__, "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 && initialized;

        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(__func__, "normal interrupt end");

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

static void recalibrate_floppy(void)
{
        debugt(__func__, "");
        do_floppy = recal_interrupt;
        output_byte(FD_RECALIBRATE);
        if (output_byte(UNIT(current_drive)) < 0)
                reset_fdc();
}

/*
 * Must do 4 FD_SENSEIs after reset because of ``drive polling''.
 */
static void reset_interrupt(void)
{
        debugt(__func__, "");
        result();               /* get the status ready for set_fdc */
        if (FDCS->reset) {
                pr_info("reset set in interrupt, calling %pf\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;

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

        pr_info("timeout_message=%s\n", timeout_message);
        pr_info("last output bytes:\n");
        for (i = 0; i < OLOGSIZE; i++)
                pr_info("%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);
        pr_info("last result at %lu\n", resultjiffies);
        pr_info("last redo_fd_request at %lu\n", lastredo);
        print_hex_dump(KERN_INFO, "", DUMP_PREFIX_NONE, 16, 1,
                       reply_buffer, resultsize, true);

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

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

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

/* 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)
{
        if (FDCS->reset) {
                reset_fdc();
                return;
        }
        if (start_motor(floppy_ready))
                return;
        if (fdc_dtr())
                return;

        debug_dcl(DP->flags, "calling disk change from floppy_ready\n");
        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");

        scandrives();
        debug_dcl(DP->flags, "setting NEWCHANGE in floppy_start\n");
        set_bit(FD_DISK_NEWCHANGE_BIT, &DRS->flags);
        floppy_ready();
}

/*
 * ========================================================================
 * here ends the bottom half. Exported routines are:
 * floppy_start, floppy_off, floppy_ready, lock_fdc, unlock_fdc, set_fdc,
 * start_motor, reset_fdc, reset_fdc_info, interpret_errors.
 * Initialization also uses output_byte, result, set_dor, floppy_interrupt
 * and set_dor.
 * ========================================================================
 */
/*
 * General purpose continuations.
 * ==============================
 */

static void do_wakeup(void)
{
        reschedule_timeout(MAXTIMEOUT, "do wakeup");
        cont = NULL;
        command_status += 2;
        wake_up(&command_done);
}

static const struct cont_t wakeup_cont = {
        .interrupt      = empty,
        .redo           = do_wakeup,
        .error          = empty,
        .done           = (done_f)empty
};

static const struct cont_t intr_cont = {
        .interrupt      = empty,
        .redo           = process_fd_request,
        .error          = empty,
        .done           = (done_f)empty
};

static int wait_til_done(void (*handler)(void), bool interruptible)
{
        int ret;

        schedule_bh(handler);

        if (interruptible)

                wait_event_interruptible(command_done, command_status >= 2);
        else
                wait_event(command_done, command_status >= 2);

        if (command_status < 2) {
                cancel_activity();
                cont = &intr_cont;
                reset_fdc();
                return -EINTR;
        }

        if (FDCS->reset)
                command_status = FD_COMMAND_ERROR;
        if (command_status == FD_COMMAND_OKAY)
                ret = 0;
        else
                ret = -EIO;
        command_status = FD_COMMAND_NONE;
        return ret;
}

static void generic_done(int result)
{
        command_status = result;
        cont = &wakeup_cont;
}

static void generic_success(void)
{
        cont->done(1);
}

static void generic_failure(void)
{
        cont->done(0);
}

static void success_and_wakeup(void)
{
        generic_success();
        cont->redo();
}

/*
 * formatting and rw support.
 * ==========================
 */

static int next_valid_format(void)
{
        int probed_format;

        probed_format = DRS->probed_format;
        while (1) {
                if (probed_format >= 8 || !DP->autodetect[probed_format]) {
                        DRS->probed_format = 0;
                        return 1;
                }
                if (floppy_type[DP->autodetect[probed_format]].sect) {
                        DRS->probed_format = probed_format;
                        return 0;
                }
                probed_format++;
        }
}

static void bad_flp_intr(void)
{
        int err_count;

        if (probing) {
                DRS->probed_format++;
                if (!next_valid_format())
                        return;
        }
        err_count = ++(*errors);
        INFBOUND(DRWE->badness, err_count);
        if (err_count > DP->max_errors.abort)
                cont->done(0);
        if (err_count > DP->max_errors.reset)
                FDCS->reset = 1;
        else if (err_count > DP->max_errors.recal)
                DRS->track = NEED_2_RECAL;
}

static void set_floppy(int drive)
{
        int type = ITYPE(UDRS->fd_device);

        if (type)
                _floppy = floppy_type + type;
        else
                _floppy = current_type[drive];
}

/*
 * formatting support.
 * ===================
 */
static void format_interrupt(void)
{
        switch (interpret_errors()) {
        case 1:
                cont->error();
        case 2:
                break;
        case 0:
                cont->done(1);
        }
        cont->redo();
}

#define FM_MODE(x, y) ((y) & ~(((x)->rate & 0x80) >> 1))
#define CT(x) ((x) | 0xc0)

static void setup_format_params(int track)
{
        int n;
        int il;
        int count;
        int head_shift;
        int track_shift;
        struct fparm {
                unsigned char track, head, sect, size;
        } *here = (struct fparm *)floppy_track_buffer;

        raw_cmd = &default_raw_cmd;
        raw_cmd->track = track;

        raw_cmd->flags = (FD_RAW_WRITE | FD_RAW_INTR | FD_RAW_SPIN |
                          FD_RAW_NEED_DISK | FD_RAW_NEED_SEEK);
        raw_cmd->rate = _floppy->rate & 0x43;
        raw_cmd->cmd_count = NR_F;
        COMMAND = FM_MODE(_floppy, FD_FORMAT);
        DR_SELECT = UNIT(current_drive) + PH_HEAD(_floppy, format_req.head);
        F_SIZECODE = FD_SIZECODE(_floppy);
        F_SECT_PER_TRACK = _floppy->sect << 2 >> F_SIZECODE;
        F_GAP = _floppy->fmt_gap;
        F_FILL = FD_FILL_BYTE;

        raw_cmd->kernel_data = floppy_track_buffer;
        raw_cmd->length = 4 * F_SECT_PER_TRACK;

        /* allow for about 30ms for data transport per track */
        head_shift = (F_SECT_PER_TRACK + 5) / 6;

        /* a ``cylinder'' is two tracks plus a little stepping time */
        track_shift = 2 * head_shift + 3;

        /* position of logical sector 1 on this track */
        n = (track_shift * format_req.track + head_shift * format_req.head)
            % F_SECT_PER_TRACK;

        /* determine interleave */
        il = 1;
        if (_floppy->fmt_gap < 0x22)
                il++;

        /* initialize field */
        for (count = 0; count < F_SECT_PER_TRACK; ++count) {
                here[count].track = format_req.track;
                here[count].head = format_req.head;
                here[count].sect = 0;
                here[count].size = F_SIZECODE;
        }
        /* place logical sectors */
        for (count = 1; count <= F_SECT_PER_TRACK; ++count) {
                here[n].sect = count;
                n = (n + il) % F_SECT_PER_TRACK;
                if (here[n].sect) {     /* sector busy, find next free sector */
                        ++n;
                        if (n >= F_SECT_PER_TRACK) {
                                n -= F_SECT_PER_TRACK;
                                while (here[n].sect)
                                        ++n;
                        }
                }
        }
        if (_floppy->stretch & FD_SECTBASEMASK) {
                for (count = 0; count < F_SECT_PER_TRACK; count++)
                        here[count].sect += FD_SECTBASE(_floppy) - 1;
        }
}

static void redo_format(void)
{
        buffer_track = -1;
        setup_format_params(format_req.track << STRETCH(_floppy));
        floppy_start();
        debugt(__func__, "queue format request");
}

static const struct cont_t format_cont = {
        .interrupt      = format_interrupt,
        .redo           = redo_format,
        .error          = bad_flp_intr,
        .done           = generic_done
};

static int do_format(int drive, struct format_descr *tmp_format_req)
{
        int ret;

        if (lock_fdc(drive, true))
                return -EINTR;

        set_floppy(drive);
        if (!_floppy ||
            _floppy->track > DP->tracks ||
            tmp_format_req->track >= _floppy->track ||
            tmp_format_req->head >= _floppy->head ||
            (_floppy->sect << 2) % (1 << FD_SIZECODE(_floppy)) ||
            !_floppy->fmt_gap) {
                process_fd_request();
                return -EINVAL;
        }
        format_req = *tmp_format_req;
        format_errors = 0;
        cont = &format_cont;
        errors = &format_errors;
        ret = wait_til_done(redo_format, true);
        if (ret == -EINTR)
                return -EINTR;
        process_fd_request();
        return ret;
}

/*
 * Buffer read/write and support
 * =============================
 */

static void floppy_end_request(struct request *req, int error)
{
        unsigned int nr_sectors = current_count_sectors;
        unsigned int drive = (unsigned long)req->rq_disk->private_data;

        /* current_count_sectors can be zero if transfer failed */
        if (error)
                nr_sectors = blk_rq_cur_sectors(req);
        if (__blk_end_request(req, error, nr_sectors << 9))
                return;

        /* We're done with the request */
        floppy_off(drive);
        current_req = NULL;
}

/* new request_done. Can handle physical sectors which are smaller than a
 * logical buffer */
static void request_done(int uptodate)
{
        struct request *req = current_req;
        struct request_queue *q;
        unsigned long flags;
        int block;
        char msg[sizeof("request done ") + sizeof(int) * 3];

        probing = 0;
        snprintf(msg, sizeof(msg), "request done %d", uptodate);
        reschedule_timeout(MAXTIMEOUT, msg);

        if (!req) {
                pr_info("floppy.c: no request in request_done\n");
                return;
        }

        q = req->q;

        if (uptodate) {
                /* maintain values for invalidation on geometry
                 * change */
                block = current_count_sectors + blk_rq_pos(req);
                INFBOUND(DRS->maxblock, block);
                if (block > _floppy->sect)
                        DRS->maxtrack = 1;

                /* unlock chained buffers */
                spin_lock_irqsave(q->queue_lock, flags);
                floppy_end_request(req, 0);
                spin_unlock_irqrestore(q->queue_lock, flags);
        } else {
                if (rq_data_dir(req) == WRITE) {
                        /* record write error information */
                        DRWE->write_errors++;
                        if (DRWE->write_errors == 1) {
                                DRWE->first_error_sector = blk_rq_pos(req);
                                DRWE->first_error_generation = DRS->generation;
                        }
                        DRWE->last_error_sector = blk_rq_pos(req);
                        DRWE->last_error_generation = DRS->generation;
                }
                spin_lock_irqsave(q->queue_lock, flags);
                floppy_end_request(req, -EIO);
                spin_unlock_irqrestore(q->queue_lock, flags);
        }
}

/* Interrupt handler evaluating the result of the r/w operation */
static void rw_interrupt(void)
{
        int eoc;
        int ssize;
        int heads;
        int nr_sectors;

        if (R_HEAD >= 2) {
                /* some Toshiba floppy controllers occasionnally seem to
                 * return bogus interrupts after read/write operations, which
                 * can be recognized by a bad head number (>= 2) */
                return;
        }

        if (!DRS->first_read_date)
                DRS->first_read_date = jiffies;

        nr_sectors = 0;
        ssize = DIV_ROUND_UP(1 << SIZECODE, 4);

        if (ST1 & ST1_EOC)
                eoc = 1;
        else
                eoc = 0;

        if (COMMAND & 0x80)
                heads = 2;
        else
                heads = 1;

        nr_sectors = (((R_TRACK - TRACK) * heads +
                       R_HEAD - HEAD) * SECT_PER_TRACK +
                      R_SECTOR - SECTOR + eoc) << SIZECODE >> 2;

        if (nr_sectors / ssize >
            DIV_ROUND_UP(in_sector_offset + current_count_sectors, ssize)) {
                DPRINT("long rw: %x instead of %lx\n",
                       nr_sectors, current_count_sectors);
                pr_info("rs=%d s=%d\n", R_SECTOR, SECTOR);
                pr_info("rh=%d h=%d\n", R_HEAD, HEAD);
                pr_info("rt=%d t=%d\n", R_TRACK, TRACK);
                pr_info("heads=%d eoc=%d\n", heads, eoc);
                pr_info("spt=%d st=%d ss=%d\n",
                        SECT_PER_TRACK, fsector_t, ssize);
                pr_info("in_sector_offset=%d\n", in_sector_offset);
        }

        nr_sectors -= in_sector_offset;
        INFBOUND(nr_sectors, 0);
        SUPBOUND(current_count_sectors, nr_sectors);

        switch (interpret_errors()) {
        case 2:
                cont->redo();
                return;
        case 1:
                if (!current_count_sectors) {
                        cont->error();
                        cont->redo();
                        return;
                }
                break;
        case 0:
                if (!current_count_sectors) {
                        cont->redo();
                        return;
                }
                current_type[current_drive] = _floppy;
                floppy_sizes[TOMINOR(current_drive)] = _floppy->size;
                break;
        }

        if (probing) {
                if (DP->flags & FTD_MSG)
                        DPRINT("Auto-detected floppy type %s in fd%d\n",
                               _floppy->name, current_drive);
                current_type[current_drive] = _floppy;
                floppy_sizes[TOMINOR(current_drive)] = _floppy->size;
                probing = 0;
        }

        if (CT(COMMAND) != FD_READ ||
            raw_cmd->kernel_data == current_req->buffer) {
                /* transfer directly from buffer */
                cont->done(1);
        } else if (CT(COMMAND) == FD_READ) {
                buffer_track = raw_cmd->track;
                buffer_drive = current_drive;
                INFBOUND(buffer_max, nr_sectors + fsector_t);
        }
        cont->redo();
}

/* Compute maximal contiguous buffer size. */
static int buffer_chain_size(void)
{
        struct bio_vec *bv;
        int size;
        struct req_iterator iter;
        char *base;

        base = bio_data(current_req->bio);
        size = 0;

        rq_for_each_segment(bv, current_req, iter) {
                if (page_address(bv->bv_page) + bv->bv_offset != base + size)
                        break;

                size += bv->bv_len;
        }

        return size >> 9;
}

/* Compute the maximal transfer size */
static int transfer_size(int ssize, int max_sector, int max_size)
{
        SUPBOUND(max_sector, fsector_t + max_size);

        /* alignment */
        max_sector -= (max_sector % _floppy->sect) % ssize;

        /* transfer size, beginning not aligned */
        current_count_sectors = max_sector - fsector_t;

        return max_sector;
}

/*
 * Move data from/to the track buffer to/from the buffer cache.
 */
static void copy_buffer(int ssize, int max_sector, int max_sector_2)
{
        int remaining;          /* number of transferred 512-byte sectors */
        struct bio_vec *bv;
        char *buffer;
        char *dma_buffer;
        int size;
        struct req_iterator iter;

        max_sector = transfer_size(ssize,
                                   min(max_sector, max_sector_2),
                                   blk_rq_sectors(current_req));

        if (current_count_sectors <= 0 && CT(COMMAND) == FD_WRITE &&
            buffer_max > fsector_t + blk_rq_sectors(current_req))
                current_count_sectors = min_t(int, buffer_max - fsector_t,
                                              blk_rq_sectors(current_req));

        remaining = current_count_sectors << 9;
        if (remaining > blk_rq_bytes(current_req) && CT(COMMAND) == FD_WRITE) {
                DPRINT("in copy buffer\n");
                pr_info("current_count_sectors=%ld\n", current_count_sectors);
                pr_info("remaining=%d\n", remaining >> 9);
                pr_info("current_req->nr_sectors=%u\n",
                        blk_rq_sectors(current_req));
                pr_info("current_req->current_nr_sectors=%u\n",
                        blk_rq_cur_sectors(current_req));
                pr_info("max_sector=%d\n", max_sector);
                pr_info("ssize=%d\n", ssize);
        }

        buffer_max = max(max_sector, buffer_max);

        dma_buffer = floppy_track_buffer + ((fsector_t - buffer_min) << 9);

        size = blk_rq_cur_bytes(current_req);

        rq_for_each_segment(bv, current_req, iter) {
                if (!remaining)
                        break;

                size = bv->bv_len;
                SUPBOUND(size, remaining);

                buffer = page_address(bv->bv_page) + bv->bv_offset;
                if (dma_buffer + size >
                    floppy_track_buffer + (max_buffer_sectors << 10) ||
                    dma_buffer < floppy_track_buffer) {
                        DPRINT("buffer overrun in copy buffer %d\n",
                               (int)((floppy_track_buffer - dma_buffer) >> 9));
                        pr_info("fsector_t=%d buffer_min=%d\n",
                                fsector_t, buffer_min);
                        pr_info("current_count_sectors=%ld\n",
                                current_count_sectors);
                        if (CT(COMMAND) == FD_READ)
                                pr_info("read\n");
                        if (CT(COMMAND) == FD_WRITE)
                                pr_info("write\n");
                        break;
                }
                if (((unsigned long)buffer) % 512)
                        DPRINT("%p buffer not aligned\n", buffer);

                if (CT(COMMAND) == FD_READ)
                        memcpy(buffer, dma_buffer, size);
                else
                        memcpy(dma_buffer, buffer, size);

                remaining -= size;
                dma_buffer += size;
        }
        if (remaining) {
                if (remaining > 0)
                        max_sector -= remaining >> 9;
                DPRINT("weirdness: remaining %d\n", remaining >> 9);
        }
}

/* work around a bug in pseudo DMA
 * (on some FDCs) pseudo DMA does not stop when the CPU stops
 * sending data.  Hence we need a different way to signal the
 * transfer length:  We use SECT_PER_TRACK.  Unfortunately, this
 * does not work with MT, hence we can only transfer one head at
 * a time
 */
static void virtualdmabug_workaround(void)
{
        int hard_sectors;
        int end_sector;

        if (CT(COMMAND) == FD_WRITE) {
                COMMAND &= ~0x80;       /* switch off multiple track mode */

                hard_sectors = raw_cmd->length >> (7 + SIZECODE);
                end_sector = SECTOR + hard_sectors - 1;
                if (end_sector > SECT_PER_TRACK) {
                        pr_info("too many sectors %d > %d\n",
                                end_sector, SECT_PER_TRACK);
                        return;
                }
                SECT_PER_TRACK = end_sector;
                                        /* make sure SECT_PER_TRACK
                                         * points to end of transfer */
        }
}

/*
 * Formulate a read/write request.
 * this routine decides where to load the data (directly to buffer, or to
 * tmp floppy area), how much data to load (the size of the buffer, the whole
 * track, or a single sector)
 * All floppy_track_buffer handling goes in here. If we ever add track buffer
 * allocation on the fly, it should be done here. No other part should need
 * modification.
 */

static int make_raw_rw_request(void)
{
        int aligned_sector_t;
        int max_sector;
        int max_size;
        int tracksize;
        int ssize;

        if (WARN(max_buffer_sectors == 0, "VFS: Block I/O scheduled on unopened device\n"))
                return 0;

        set_fdc((long)current_req->rq_disk->private_data);

        raw_cmd = &default_raw_cmd;
        raw_cmd->flags = FD_RAW_SPIN | FD_RAW_NEED_DISK | FD_RAW_NEED_DISK |
            FD_RAW_NEED_SEEK;
        raw_cmd->cmd_count = NR_RW;
        if (rq_data_dir(current_req) == READ) {
                raw_cmd->flags |= FD_RAW_READ;
                COMMAND = FM_MODE(_floppy, FD_READ);
        } else if (rq_data_dir(current_req) == WRITE) {
                raw_cmd->flags |= FD_RAW_WRITE;
                COMMAND = FM_MODE(_floppy, FD_WRITE);
        } else {
                DPRINT("%s: unknown command\n", __func__);
                return 0;
        }

        max_sector = _floppy->sect * _floppy->head;

        TRACK = (int)blk_rq_pos(current_req) / max_sector;
        fsector_t = (int)blk_rq_pos(current_req) % max_sector;
        if (_floppy->track && TRACK >= _floppy->track) {
                if (blk_rq_cur_sectors(current_req) & 1) {
                        current_count_sectors = 1;
                        return 1;
                } else
                        return 0;
        }
        HEAD = fsector_t / _floppy->sect;

        if (((_floppy->stretch & (FD_SWAPSIDES | FD_SECTBASEMASK)) ||
             test_bit(FD_NEED_TWADDLE_BIT, &DRS->flags)) &&
            fsector_t < _floppy->sect)
                max_sector = _floppy->sect;

        /* 2M disks have phantom sectors on the first track */
        if ((_floppy->rate & FD_2M) && (!TRACK) && (!HEAD)) {
                max_sector = 2 * _floppy->sect / 3;
                if (fsector_t >= max_sector) {
                        current_count_sectors =
                            min_t(int, _floppy->sect - fsector_t,
                                  blk_rq_sectors(current_req));
                        return 1;
                }
                SIZECODE = 2;
        } else
                SIZECODE = FD_SIZECODE(_floppy);
        raw_cmd->rate = _floppy->rate & 0x43;
        if ((_floppy->rate & FD_2M) && (TRACK || HEAD) && raw_cmd->rate == 2)
                raw_cmd->rate = 1;

        if (SIZECODE)
                SIZECODE2 = 0xff;
        else
                SIZECODE2 = 0x80;
        raw_cmd->track = TRACK << STRETCH(_floppy);
        DR_SELECT = UNIT(current_drive) + PH_HEAD(_floppy, HEAD);
        GAP = _floppy->gap;
        ssize = DIV_ROUND_UP(1 << SIZECODE, 4);
        SECT_PER_TRACK = _floppy->sect << 2 >> SIZECODE;
        SECTOR = ((fsector_t % _floppy->sect) << 2 >> SIZECODE) +
            FD_SECTBASE(_floppy);

        /* tracksize describes the size which can be filled up with sectors
         * of size ssize.
         */
        tracksize = _floppy->sect - _floppy->sect % ssize;
        if (tracksize < _floppy->sect) {
                SECT_PER_TRACK++;
                if (tracksize <= fsector_t % _floppy->sect)
                        SECTOR--;

                /* if we are beyond tracksize, fill up using smaller sectors */
                while (tracksize <= fsector_t % _floppy->sect) {
                        while (tracksize + ssize > _floppy->sect) {
                                SIZECODE--;
                                ssize >>= 1;
                        }
                        SECTOR++;
                        SECT_PER_TRACK++;
                        tracksize += ssize;
                }
                max_sector = HEAD * _floppy->sect + tracksize;
        } else if (!TRACK && !HEAD && !(_floppy->rate & FD_2M) && probing) {
                max_sector = _floppy->sect;
        } else if (!HEAD && CT(COMMAND) == FD_WRITE) {
                /* for virtual DMA bug workaround */
                max_sector = _floppy->sect;
        }

        in_sector_offset = (fsector_t % _floppy->sect) % ssize;
        aligned_sector_t = fsector_t - in_sector_offset;
        max_size = blk_rq_sectors(current_req);
        if ((raw_cmd->track == buffer_track) &&
            (current_drive == buffer_drive) &&
            (fsector_t >= buffer_min) && (fsector_t < buffer_max)) {
                /* data already in track buffer */
                if (CT(COMMAND) == FD_READ) {
                        copy_buffer(1, max_sector, buffer_max);
                        return 1;
                }
        } else if (in_sector_offset || blk_rq_sectors(current_req) < ssize) {
                if (CT(COMMAND) == FD_WRITE) {
                        unsigned int sectors;

                        sectors = fsector_t + blk_rq_sectors(current_req);
                        if (sectors > ssize && sectors < ssize + ssize)
                                max_size = ssize + ssize;
                        else
                                max_size = ssize;
                }
                raw_cmd->flags &= ~FD_RAW_WRITE;
                raw_cmd->flags |= FD_RAW_READ;
                COMMAND = FM_MODE(_floppy, FD_READ);
        } else if ((unsigned long)current_req->buffer < MAX_DMA_ADDRESS) {
                unsigned long dma_limit;
                int direct, indirect;

                indirect =
                    transfer_size(ssize, max_sector,
                                  max_buffer_sectors * 2) - fsector_t;

                /*
                 * Do NOT use minimum() here---MAX_DMA_ADDRESS is 64 bits wide
                 * on a 64 bit machine!
                 */
                max_size = buffer_chain_size();
                dma_limit = (MAX_DMA_ADDRESS -
                             ((unsigned long)current_req->buffer)) >> 9;
                if ((unsigned long)max_size > dma_limit)
                        max_size = dma_limit;
                /* 64 kb boundaries */
                if (CROSS_64KB(current_req->buffer, max_size << 9))
                        max_size = (K_64 -
                                    ((unsigned long)current_req->buffer) %
                                    K_64) >> 9;
                direct = transfer_size(ssize, max_sector, max_size) - fsector_t;
                /*
                 * We try to read tracks, but if we get too many errors, we
                 * go back to reading just one sector at a time.
                 *
                 * This means we should be able to read a sector even if there
                 * are other bad sectors on this track.
                 */
                if (!direct ||
                    (indirect * 2 > direct * 3 &&
                     *errors < DP->max_errors.read_track &&
                     ((!probing ||
                       (DP->read_track & (1 << DRS->probed_format)))))) {
                        max_size = blk_rq_sectors(current_req);
                } else {
                        raw_cmd->kernel_data = current_req->buffer;
                        raw_cmd->length = current_count_sectors << 9;
                        if (raw_cmd->length == 0) {
                                DPRINT("%s: zero dma transfer attempted\n", __func__);
                                DPRINT("indirect=%d direct=%d fsector_t=%d\n",
                                       indirect, direct, fsector_t);
                                return 0;
                        }
                        virtualdmabug_workaround();
                        return 2;
                }
        }

        if (CT(COMMAND) == FD_READ)
                max_size = max_sector;  /* unbounded */

        /* claim buffer track if needed */
        if (buffer_track != raw_cmd->track ||   /* bad track */
            buffer_drive != current_drive ||    /* bad drive */
            fsector_t > buffer_max ||
            fsector_t < buffer_min ||
            ((CT(COMMAND) == FD_READ ||
              (!in_sector_offset && blk_rq_sectors(current_req) >= ssize)) &&
             max_sector > 2 * max_buffer_sectors + buffer_min &&
             max_size + fsector_t > 2 * max_buffer_sectors + buffer_min)) {
                /* not enough space */
                buffer_track = -1;
                buffer_drive = current_drive;
                buffer_max = buffer_min = aligned_sector_t;
        }
        raw_cmd->kernel_data = floppy_track_buffer +
                ((aligned_sector_t - buffer_min) << 9);

        if (CT(COMMAND) == FD_WRITE) {
                /* copy write buffer to track buffer.
                 * if we get here, we know that the write
                 * is either aligned or the data already in the buffer
                 * (buffer will be overwritten) */
                if (in_sector_offset && buffer_track == -1)
                        DPRINT("internal error offset !=0 on write\n");
                buffer_track = raw_cmd->track;
                buffer_drive = current_drive;
                copy_buffer(ssize, max_sector,
                            2 * max_buffer_sectors + buffer_min);
        } else
                transfer_size(ssize, max_sector,
                              2 * max_buffer_sectors + buffer_min -
                              aligned_sector_t);

        /* round up current_count_sectors to get dma xfer size */
        raw_cmd->length = in_sector_offset + current_count_sectors;
        raw_cmd->length = ((raw_cmd->length - 1) | (ssize - 1)) + 1;
        raw_cmd->length <<= 9;
        if ((raw_cmd->length < current_count_sectors << 9) ||
            (raw_cmd->kernel_data != current_req->buffer &&
             CT(COMMAND) == FD_WRITE &&
             (aligned_sector_t + (raw_cmd->length >> 9) > buffer_max ||
              aligned_sector_t < buffer_min)) ||
            raw_cmd->length % (128 << SIZECODE) ||
            raw_cmd->length <= 0 || current_count_sectors <= 0) {
                DPRINT("fractionary current count b=%lx s=%lx\n",
                       raw_cmd->length, current_count_sectors);
                if (raw_cmd->kernel_data != current_req->buffer)
                        pr_info("addr=%d, length=%ld\n",
                                (int)((raw_cmd->kernel_data -
                                       floppy_track_buffer) >> 9),
                                current_count_sectors);
                pr_info("st=%d ast=%d mse=%d msi=%d\n",
                        fsector_t, aligned_sector_t, max_sector, max_size);
                pr_info("ssize=%x SIZECODE=%d\n", ssize, SIZECODE);
                pr_info("command=%x SECTOR=%d HEAD=%d, TRACK=%d\n",
                        COMMAND, SECTOR, HEAD, TRACK);
                pr_info("buffer drive=%d\n", buffer_drive);
                pr_info("buffer track=%d\n", buffer_track);
                pr_info("buffer_min=%d\n", buffer_min);
                pr_info("buffer_max=%d\n", buffer_max);
                return 0;
        }

        if (raw_cmd->kernel_data != current_req->buffer) {
                if (raw_cmd->kernel_data < floppy_track_buffer ||
                    current_count_sectors < 0 ||
                    raw_cmd->length < 0 ||
                    raw_cmd->kernel_data + raw_cmd->length >
                    floppy_track_buffer + (max_buffer_sectors << 10)) {
                        DPRINT("buffer overrun in schedule dma\n");
                        pr_info("fsector_t=%d buffer_min=%d current_count=%ld\n",
                                fsector_t, buffer_min, raw_cmd->length >> 9);
                        pr_info("current_count_sectors=%ld\n",
                                current_count_sectors);
                        if (CT(COMMAND) == FD_READ)
                                pr_info("read\n");
                        if (CT(COMMAND) == FD_WRITE)
                                pr_info("write\n");
                        return 0;
                }
        } else if (raw_cmd->length > blk_rq_bytes(current_req) ||
                   current_count_sectors > blk_rq_sectors(current_req)) {
                DPRINT("buffer overrun in direct transfer\n");
                return 0;
        } else if (raw_cmd->length < current_count_sectors << 9) {
                DPRINT("more sectors than bytes\n");
                pr_info("bytes=%ld\n", raw_cmd->length >> 9);
                pr_info("sectors=%ld\n", current_count_sectors);
        }
        if (raw_cmd->length == 0) {
                DPRINT("zero dma transfer attempted from make_raw_request\n");
                return 0;
        }

        virtualdmabug_workaround();
        return 2;
}

/*
 * Round-robin between our available drives, doing one request from each
 */
static int set_next_request(void)
{
        struct request_queue *q;
        int old_pos = fdc_queue;

        do {
                q = disks[fdc_queue]->queue;
                if (++fdc_queue == N_DRIVE)
                        fdc_queue = 0;
                if (q) {
                        current_req = blk_fetch_request(q);
                        if (current_req)
                                break;
                }
        } while (fdc_queue != old_pos);

        return current_req != NULL;
}

static void redo_fd_request(void)
{
        int drive;
        int tmp;

        lastredo = jiffies;
        if (current_drive < N_DRIVE)
                floppy_off(current_drive);

do_request:
        if (!current_req) {
                int pending;

                spin_lock_irq(&floppy_lock);
                pending = set_next_request();
                spin_unlock_irq(&floppy_lock);

                if (!pending) {
                        do_floppy = NULL;
                        unlock_fdc();
                        return;
                }
        }
        drive = (long)current_req->rq_disk->private_data;
        set_fdc(drive);
        reschedule_timeout(current_reqD, "redo fd request");

        set_floppy(drive);
        raw_cmd = &default_raw_cmd;
        raw_cmd->flags = 0;
        if (start_motor(redo_fd_request))
                return;

        disk_change(current_drive);
        if (test_bit(current_drive, &fake_change) ||
            test_bit(FD_DISK_CHANGED_BIT, &DRS->flags)) {
                DPRINT("disk absent or changed during operation\n");
                request_done(0);
                goto do_request;
        }
        if (!_floppy) { /* Autodetection */
                if (!probing) {
                        DRS->probed_format = 0;
                        if (next_valid_format()) {
                                DPRINT("no autodetectable formats\n");
                                _floppy = NULL;
                                request_done(0);
                                goto do_request;
                        }
                }
                probing = 1;
                _floppy = floppy_type + DP->autodetect[DRS->probed_format];
        } else
                probing = 0;
        errors = &(current_req->errors);
        tmp = make_raw_rw_request();
        if (tmp < 2) {
                request_done(tmp);
                goto do_request;
        }

        if (test_bit(FD_NEED_TWADDLE_BIT, &DRS->flags))
                twaddle();
        schedule_bh(floppy_start);
        debugt(__func__, "queue fd request");
        return;
}

static const struct cont_t rw_cont = {
        .interrupt      = rw_interrupt,
        .redo           = redo_fd_request,
        .error          = bad_flp_intr,
        .done           = request_done
};

static void process_fd_request(void)
{
        cont = &rw_cont;
        schedule_bh(redo_fd_request);
}

static void do_fd_request(struct request_queue *q)
{
        if (WARN(max_buffer_sectors == 0,
                 "VFS: %s called on non-open device\n", __func__))
                return;

        if (WARN(atomic_read(&usage_count) == 0,
                 "warning: usage count=0, current_req=%p sect=%ld type=%x flags=%x\n",
                 current_req, (long)blk_rq_pos(current_req), current_req->cmd_type,
                 current_req->cmd_flags))
                return;

        if (test_bit(0, &fdc_busy)) {
                /* fdc busy, this new request will be treated when the
                   current one is done */
                is_alive(__func__, "old request running");
                return;
        }
        lock_fdc(MAXTIMEOUT, false);
        process_fd_request();
        is_alive(__func__, "");
}

static const struct cont_t poll_cont = {
        .interrupt      = success_and_wakeup,
        .redo           = floppy_ready,
        .error          = generic_failure,
        .done           = generic_done
};

static int poll_drive(bool interruptible, int flag)
{
        /* no auto-sense, just clear dcl */
        raw_cmd = &default_raw_cmd;
        raw_cmd->flags = flag;
        raw_cmd->track = 0;
        raw_cmd->cmd_count = 0;
        cont = &poll_cont;
        debug_dcl(DP->flags, "setting NEWCHANGE in poll_drive\n");
        set_bit(FD_DISK_NEWCHANGE_BIT, &DRS->flags);

        return wait_til_done(floppy_ready, interruptible);
}

/*
 * User triggered reset
 * ====================
 */

static void reset_intr(void)
{
        pr_info("weird, reset interrupt called\n");
}

static const struct cont_t reset_cont = {
        .interrupt      = reset_intr,
        .redo           = success_and_wakeup,
        .error          = generic_failure,
        .done           = generic_done
};

static int user_reset_fdc(int drive, int arg, bool interruptible)
{
        int ret;

        if (lock_fdc(drive, interruptible))
                return -EINTR;

        if (arg == FD_RESET_ALWAYS)
                FDCS->reset = 1;
        if (FDCS->reset) {
                cont = &reset_cont;
                ret = wait_til_done(reset_fdc, interruptible);
                if (ret == -EINTR)
                        return -EINTR;

        }
        process_fd_request();
        return 0;
}

/*
 * Misc Ioctl's and support
 * ========================
 */
static inline int fd_copyout(void __user *param, const void *address,
                             unsigned long size)
{
        return copy_to_user(param, address, size) ? -EFAULT : 0;
}

static inline int fd_copyin(void __user *param, void *address,
                            unsigned long size)
{
        return copy_from_user(address, param, size) ? -EFAULT : 0;
}

static const char *drive_name(int type, int drive)
{
        struct floppy_struct *floppy;

        if (type)
                floppy = floppy_type + type;
        else {
                if (UDP->native_format)
                        floppy = floppy_type + UDP->native_format;
                else
                        return "(null)";
        }
        if (floppy->name)
                return floppy->name;
        else
                return "(null)";
}

/* raw commands */
static void raw_cmd_done(int flag)
{
        int i;

        if (!flag) {
                raw_cmd->flags |= FD_RAW_FAILURE;
                raw_cmd->flags |= FD_RAW_HARDFAILURE;
        } else {
                raw_cmd->reply_count = inr;
                if (raw_cmd->reply_count > MAX_REPLIES)
                        raw_cmd->reply_count = 0;
                for (i = 0; i < raw_cmd->reply_count; i++)
                        raw_cmd->reply[i] = reply_buffer[i];

                if (raw_cmd->flags & (FD_RAW_READ | FD_RAW_WRITE)) {
                        unsigned long flags;
                        flags = claim_dma_lock();
                        raw_cmd->length = fd_get_dma_residue();
                        release_dma_lock(flags);
                }

                if ((raw_cmd->flags & FD_RAW_SOFTFAILURE) &&
                    (!raw_cmd->reply_count || (raw_cmd->reply[0] & 0xc0)))
                        raw_cmd->flags |= FD_RAW_FAILURE;

                if (disk_change(current_drive))
                        raw_cmd->flags |= FD_RAW_DISK_CHANGE;
                else
                        raw_cmd->flags &= ~FD_RAW_DISK_CHANGE;
                if (raw_cmd->flags & FD_RAW_NO_MOTOR_AFTER)
                        motor_off_callback(current_drive);

                if (raw_cmd->next &&
                    (!(raw_cmd->flags & FD_RAW_FAILURE) ||
                     !(raw_cmd->flags & FD_RAW_STOP_IF_FAILURE)) &&
                    ((raw_cmd->flags & FD_RAW_FAILURE) ||
                     !(raw_cmd->flags & FD_RAW_STOP_IF_SUCCESS))) {
                        raw_cmd = raw_cmd->next;
                        return;
                }
        }
        generic_done(flag);
}

static const struct cont_t raw_cmd_cont = {
        .interrupt      = success_and_wakeup,
        .redo           = floppy_start,
        .error          = generic_failure,
        .done           = raw_cmd_done
};

static int raw_cmd_copyout(int cmd, void __user *param,
                                  struct floppy_raw_cmd *ptr)
{
        int ret;

        while (ptr) {
                ret = copy_to_user(param, ptr, sizeof(*ptr));
                if (ret)
                        return -EFAULT;
                param += sizeof(struct floppy_raw_cmd);
                if ((ptr->flags & FD_RAW_READ) && ptr->buffer_length) {
                        if (ptr->length >= 0 &&
                            ptr->length <= ptr->buffer_length) {
                                long length = ptr->buffer_length - ptr->length;
                                ret = fd_copyout(ptr->data, ptr->kernel_data,
                                                 length);
                                if (ret)
                                        return ret;
                        }
                }
                ptr = ptr->next;
        }

        return 0;
}

static void raw_cmd_free(struct floppy_raw_cmd **ptr)
{
        struct floppy_raw_cmd *next;
        struct floppy_raw_cmd *this;

        this = *ptr;
        *ptr = NULL;
        while (this) {
                if (this->buffer_length) {
                        fd_dma_mem_free((unsigned long)this->kernel_data,
                                        this->buffer_length);
                        this->buffer_length = 0;
                }
                next = this->next;
                kfree(this);
                this = next;
        }
}

static int raw_cmd_copyin(int cmd, void __user *param,
                                 struct floppy_raw_cmd **rcmd)
{
        struct floppy_raw_cmd *ptr;
        int ret;
        int i;

        *rcmd = NULL;

loop:
        ptr = kmalloc(sizeof(struct floppy_raw_cmd), GFP_USER);
        if (!ptr)
                return -ENOMEM;
        *rcmd = ptr;
        ret = copy_from_user(ptr, param, sizeof(*ptr));
        if (ret)
                return -EFAULT;
        ptr->next = NULL;
        ptr->buffer_length = 0;
        param += sizeof(struct floppy_raw_cmd);
        if (ptr->cmd_count > 33)
                        /* the command may now also take up the space
                         * initially intended for the reply & the
                         * reply count. Needed for long 82078 commands
                         * such as RESTORE, which takes ... 17 command
                         * bytes. Murphy's law #137: When you reserve
                         * 16 bytes for a structure, you'll one day
                         * discover that you really need 17...
                         */
                return -EINVAL;

        for (i = 0; i < 16; i++)
                ptr->reply[i] = 0;
        ptr->resultcode = 0;
        ptr->kernel_data = NULL;

        if (ptr->flags & (FD_RAW_READ | FD_RAW_WRITE)) {
                if (ptr->length <= 0)
                        return -EINVAL;
                ptr->kernel_data = (char *)fd_dma_mem_alloc(ptr->length);
                fallback_on_nodma_alloc(&ptr->kernel_data, ptr->length);
                if (!ptr->kernel_data)
                        return -ENOMEM;
                ptr->buffer_length = ptr->length;
        }
        if (ptr->flags & FD_RAW_WRITE) {
                ret = fd_copyin(ptr->data, ptr->kernel_data, ptr->length);
                if (ret)
                        return ret;
        }

        if (ptr->flags & FD_RAW_MORE) {
                rcmd = &(ptr->next);
                ptr->rate &= 0x43;
                goto loop;
        }

        return 0;
}

static int raw_cmd_ioctl(int cmd, void __user *param)
{
        struct floppy_raw_cmd *my_raw_cmd;
        int drive;
        int ret2;
        int ret;

        if (FDCS->rawcmd <= 1)
                FDCS->rawcmd = 1;
        for (drive = 0; drive < N_DRIVE; drive++) {
                if (FDC(drive) != fdc)
                        continue;
                if (drive == current_drive) {
                        if (UDRS->fd_ref > 1) {
                                FDCS->rawcmd = 2;
                                break;
                        }
                } else if (UDRS->fd_ref) {
                        FDCS->rawcmd = 2;
                        break;
                }
        }

        if (FDCS->reset)
                return -EIO;

        ret = raw_cmd_copyin(cmd, param, &my_raw_cmd);
        if (ret) {
                raw_cmd_free(&my_raw_cmd);
                return ret;
        }

        raw_cmd = my_raw_cmd;
        cont = &raw_cmd_cont;
        ret = wait_til_done(floppy_start, true);
        debug_dcl(DP->flags, "calling disk change from raw_cmd ioctl\n");

        if (ret != -EINTR && FDCS->reset)
                ret = -EIO;

        DRS->track = NO_TRACK;

        ret2 = raw_cmd_copyout(cmd, param, my_raw_cmd);
        if (!ret)
                ret = ret2;
        raw_cmd_free(&my_raw_cmd);
        return ret;
}

static int invalidate_drive(struct block_device *bdev)
{
        /* invalidate the buffer track to force a reread */
        set_bit((long)bdev->bd_disk->private_data, &fake_change);
        process_fd_request();
        check_disk_change(bdev);
        return 0;
}

static int set_geometry(unsigned int cmd, struct floppy_struct *g,
                               int drive, int type, struct block_device *bdev)
{
        int cnt;

        /* sanity checking for parameters. */
        if (g->sect <= 0 ||
            g->head <= 0 ||
            g->track <= 0 || g->track > UDP->tracks >> STRETCH(g) ||
            /* check if reserved bits are set */
            (g->stretch & ~(FD_STRETCH | FD_SWAPSIDES | FD_SECTBASEMASK)) != 0)
                return -EINVAL;
        if (type) {
                if (!capable(CAP_SYS_ADMIN))
                        return -EPERM;
                mutex_lock(&open_lock);
                if (lock_fdc(drive, true)) {
                        mutex_unlock(&open_lock);
                        return -EINTR;
                }
                floppy_type[type] = *g;
                floppy_type[type].name = "user format";
                for (cnt = type << 2; cnt < (type << 2) + 4; cnt++)
                        floppy_sizes[cnt] = floppy_sizes[cnt + 0x80] =
                            floppy_type[type].size + 1;
                process_fd_request();
                for (cnt = 0; cnt < N_DRIVE; cnt++) {
                        struct block_device *bdev = opened_bdev[cnt];
                        if (!bdev || ITYPE(drive_state[cnt].fd_device) != type)
                                continue;
                        __invalidate_device(bdev, true);
                }
                mutex_unlock(&open_lock);
        } else {
                int oldStretch;

                if (lock_fdc(drive, true))
                        return -EINTR;
                if (cmd != FDDEFPRM) {
                        /* notice a disk change immediately, else
                         * we lose our settings immediately*/
                        if (poll_drive(true, FD_RAW_NEED_DISK) == -EINTR)
                                return -EINTR;
                }
                oldStretch = g->stretch;
                user_params[drive] = *g;
                if (buffer_drive == drive)
                        SUPBOUND(buffer_max, user_params[drive].sect);
                current_type[drive] = &user_params[drive];
                floppy_sizes[drive] = user_params[drive].size;
                if (cmd == FDDEFPRM)
                        DRS->keep_data = -1;
                else
                        DRS->keep_data = 1;
                /* invalidation. Invalidate only when needed, i.e.
                 * when there are already sectors in the buffer cache
                 * whose number will change. This is useful, because
                 * mtools often changes the geometry of the disk after
                 * looking at the boot block */
                if (DRS->maxblock > user_params[drive].sect ||
                    DRS->maxtrack ||
                    ((user_params[drive].sect ^ oldStretch) &
                     (FD_SWAPSIDES | FD_SECTBASEMASK)))
                        invalidate_drive(bdev);
                else
                        process_fd_request();
        }
        return 0;
}

/* handle obsolete ioctl's */
static unsigned int ioctl_table[] = {
        FDCLRPRM,
        FDSETPRM,
        FDDEFPRM,
        FDGETPRM,
        FDMSGON,
        FDMSGOFF,
        FDFMTBEG,
        FDFMTTRK,
        FDFMTEND,
        FDSETEMSGTRESH,
        FDFLUSH,
        FDSETMAXERRS,
        FDGETMAXERRS,
        FDGETDRVTYP,
        FDSETDRVPRM,
        FDGETDRVPRM,
        FDGETDRVSTAT,
        FDPOLLDRVSTAT,
        FDRESET,
        FDGETFDCSTAT,
        FDWERRORCLR,
        FDWERRORGET,
        FDRAWCMD,
        FDEJECT,
        FDTWADDLE
};

static int normalize_ioctl(unsigned int *cmd, int *size)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(ioctl_table); i++) {
                if ((*cmd & 0xffff) == (ioctl_table[i] & 0xffff)) {
                        *size = _IOC_SIZE(*cmd);
                        *cmd = ioctl_table[i];
                        if (*size > _IOC_SIZE(*cmd)) {
                                pr_info("ioctl not yet supported\n");
                                return -EFAULT;
                        }
                        return 0;
                }
        }
        return -EINVAL;
}

static int get_floppy_geometry(int drive, int type, struct floppy_struct **g)
{
        if (type)
                *g = &floppy_type[type];
        else {
                if (lock_fdc(drive, false))
                        return -EINTR;
                if (poll_drive(false, 0) == -EINTR)
                        return -EINTR;
                process_fd_request();
                *g = current_type[drive];
        }
        if (!*g)
                return -ENODEV;
        return 0;
}

static int fd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
{
        int drive = (long)bdev->bd_disk->private_data;
        int type = ITYPE(drive_state[drive].fd_device);
        struct floppy_struct *g;
        int ret;

        ret = get_floppy_geometry(drive, type, &g);
        if (ret)
                return ret;

        geo->heads = g->head;
        geo->sectors = g->sect;
        geo->cylinders = g->track;
        return 0;
}

static int fd_locked_ioctl(struct block_device *bdev, fmode_t mode, unsigned int cmd,
                    unsigned long param)
{
        int drive = (long)bdev->bd_disk->private_data;
        int type = ITYPE(UDRS->fd_device);
        int i;
        int ret;
        int size;
        union inparam {
                struct floppy_struct g; /* geometry */
                struct format_descr f;
                struct floppy_max_errors max_errors;
                struct floppy_drive_params dp;
        } inparam;              /* parameters coming from user space */
        const void *outparam;   /* parameters passed back to user space */

        /* convert compatibility eject ioctls into floppy eject ioctl.
         * We do this in order to provide a means to eject floppy disks before
         * installing the new fdutils package */
        if (cmd == CDROMEJECT ||        /* CD-ROM eject */
            cmd == 0x6470) {            /* SunOS floppy eject */
                DPRINT("obsolete eject ioctl\n");
                DPRINT("please use floppycontrol --eject\n");
                cmd = FDEJECT;
        }

        if (!((cmd & 0xff00) == 0x0200))
                return -EINVAL;

        /* convert the old style command into a new style command */
        ret = normalize_ioctl(&cmd, &size);
        if (ret)
                return ret;

        /* permission checks */
        if (((cmd & 0x40) && !(mode & (FMODE_WRITE | FMODE_WRITE_IOCTL))) ||
            ((cmd & 0x80) && !capable(CAP_SYS_ADMIN)))
                return -EPERM;

        if (WARN_ON(size < 0 || size > sizeof(inparam)))
                return -EINVAL;

        /* copyin */
        memset(&inparam, 0, sizeof(inparam));
        if (_IOC_DIR(cmd) & _IOC_WRITE) {
                ret = fd_copyin((void __user *)param, &inparam, size);
                if (ret)
                        return ret;
        }

        switch (cmd) {
        case FDEJECT:
                if (UDRS->fd_ref != 1)
                        /* somebody else has this drive open */
                        return -EBUSY;
                if (lock_fdc(drive, true))
                        return -EINTR;

                /* do the actual eject. Fails on
                 * non-Sparc architectures */
                ret = fd_eject(UNIT(drive));

                set_bit(FD_DISK_CHANGED_BIT, &UDRS->flags);
                set_bit(FD_VERIFY_BIT, &UDRS->flags);
                process_fd_request();
                return ret;
        case FDCLRPRM:
                if (lock_fdc(drive, true))
                        return -EINTR;
                current_type[drive] = NULL;
                floppy_sizes[drive] = MAX_DISK_SIZE << 1;
                UDRS->keep_data = 0;
                return invalidate_drive(bdev);
        case FDSETPRM:
        case FDDEFPRM:
                return set_geometry(cmd, &inparam.g, drive, type, bdev);
        case FDGETPRM:
                ret = get_floppy_geometry(drive, type,
                                          (struct floppy_struct **)&outparam);
                if (ret)
                        return ret;
                break;
        case FDMSGON:
                UDP->flags |= FTD_MSG;
                return 0;
        case FDMSGOFF:
                UDP->flags &= ~FTD_MSG;
                return 0;
        case FDFMTBEG:
                if (lock_fdc(drive, true))
                        return -EINTR;
                if (poll_drive(true, FD_RAW_NEED_DISK) == -EINTR)
                        return -EINTR;
                ret = UDRS->flags;
                process_fd_request();
                if (ret & FD_VERIFY)
                        return -ENODEV;
                if (!(ret & FD_DISK_WRITABLE))
                        return -EROFS;
                return 0;
        case FDFMTTRK:
                if (UDRS->fd_ref != 1)
                        return -EBUSY;
                return do_format(drive, &inparam.f);
        case FDFMTEND:
        case FDFLUSH:
                if (lock_fdc(drive, true))
                        return -EINTR;
                return invalidate_drive(bdev);
        case FDSETEMSGTRESH:
                UDP->max_errors.reporting = (unsigned short)(param & 0x0f);
                return 0;
        case FDGETMAXERRS:
                outparam = &UDP->max_errors;
                break;
        case FDSETMAXERRS:
                UDP->max_errors = inparam.max_errors;
                break;
        case FDGETDRVTYP:
                outparam = drive_name(type, drive);
                SUPBOUND(size, strlen((const char *)outparam) + 1);
                break;
        case FDSETDRVPRM:
                *UDP = inparam.dp;
                break;
        case FDGETDRVPRM:
                outparam = UDP;
                break;
        case FDPOLLDRVSTAT:
                if (lock_fdc(drive, true))
                        return -EINTR;
                if (poll_drive(true, FD_RAW_NEED_DISK) == -EINTR)
                        return -EINTR;
                process_fd_request();
                /* fall through */
        case FDGETDRVSTAT:
                outparam = UDRS;
                break;
        case FDRESET:
                return user_reset_fdc(drive, (int)param, true);
        case FDGETFDCSTAT:
                outparam = UFDCS;
                break;
        case FDWERRORCLR:
                memset(UDRWE, 0, sizeof(*UDRWE));
                return 0;
        case FDWERRORGET:
                outparam = UDRWE;
                break;
        case FDRAWCMD:
                if (type)
                        return -EINVAL;
                if (lock_fdc(drive, true))
                        return -EINTR;
                set_floppy(drive);
                i = raw_cmd_ioctl(cmd, (void __user *)param);
                if (i == -EINTR)
                        return -EINTR;
                process_fd_request();
                return i;
        case FDTWADDLE:
                if (lock_fdc(drive, true))
                        return -EINTR;
                twaddle();
                process_fd_request();
                return 0;
        default:
                return -EINVAL;
        }

        if (_IOC_DIR(cmd) & _IOC_READ)
                return fd_copyout((void __user *)param, outparam, size);

        return 0;
}

static int fd_ioctl(struct block_device *bdev, fmode_t mode,
                             unsigned int cmd, unsigned long param)
{
        int ret;

        mutex_lock(&floppy_mutex);
        ret = fd_locked_ioctl(bdev, mode, cmd, param);
        mutex_unlock(&floppy_mutex);

        return ret;
}

static void __init config_types(void)
{
        bool has_drive = false;
        int drive;

        /* read drive info out of physical CMOS */
        drive = 0;
        if (!UDP->cmos)
                UDP->cmos = FLOPPY0_TYPE;
        drive = 1;
        if (!UDP->cmos && FLOPPY1_TYPE)
                UDP->cmos = FLOPPY1_TYPE;

        /* FIXME: additional physical CMOS drive detection should go here */

        for (drive = 0; drive < N_DRIVE; drive++) {
                unsigned int type = UDP->cmos;
                struct floppy_drive_params *params;
                const char *name = NULL;
                static char temparea[32];

                if (type < ARRAY_SIZE(default_drive_params)) {
                        params = &default_drive_params[type].params;
                        if (type) {
                                name = default_drive_params[type].name;
                                allowed_drive_mask |= 1 << drive;
                        } else
                                allowed_drive_mask &= ~(1 << drive);
                } else {
                        params = &default_drive_params[0].params;
                        sprintf(temparea, "unknown type %d (usb?)", type);
                        name = temparea;
                }
                if (name) {
                        const char *prepend;
                        if (!has_drive) {
                                prepend = "";
                                has_drive = true;
                                pr_info("Floppy drive(s):");
                        } else {
                                prepend = ",";
                        }

                        pr_cont("%s fd%d is %s", prepend, drive, name);
                }
                *UDP = *params;
        }

        if (has_drive)
                pr_cont("\n");
}

static int floppy_release(struct gendisk *disk, fmode_t mode)
{
        int drive = (long)disk->private_data;

        mutex_lock(&floppy_mutex);
        mutex_lock(&open_lock);
        if (UDRS->fd_ref < 0)
                UDRS->fd_ref = 0;
        else if (!UDRS->fd_ref--) {
                DPRINT("floppy_release with fd_ref == 0");
                UDRS->fd_ref = 0;
        }
        if (!UDRS->fd_ref)
                opened_bdev[drive] = NULL;
        mutex_unlock(&open_lock);
        mutex_unlock(&floppy_mutex);

        return 0;
}

/*
 * floppy_open check for aliasing (/dev/fd0 can be the same as
 * /dev/PS0 etc), and disallows simultaneous access to the same
 * drive with different device numbers.
 */
static int floppy_open(struct block_device *bdev, fmode_t mode)
{
        int drive = (long)bdev->bd_disk->private_data;
        int old_dev, new_dev;
        int try;
        int res = -EBUSY;
        char *tmp;

        mutex_lock(&floppy_mutex);
        mutex_lock(&open_lock);
        old_dev = UDRS->fd_device;
        if (opened_bdev[drive] && opened_bdev[drive] != bdev)
                goto out2;

        if (!UDRS->fd_ref && (UDP->flags & FD_BROKEN_DCL)) {
                set_bit(FD_DISK_CHANGED_BIT, &UDRS->flags);
                set_bit(FD_VERIFY_BIT, &UDRS->flags);
        }

        if (UDRS->fd_ref == -1 || (UDRS->fd_ref && (mode & FMODE_EXCL)))
                goto out2;

        if (mode & FMODE_EXCL)
                UDRS->fd_ref = -1;
        else
                UDRS->fd_ref++;

        opened_bdev[drive] = bdev;

        res = -ENXIO;

        if (!floppy_track_buffer) {
                /* if opening an ED drive, reserve a big buffer,
                 * else reserve a small one */
                if ((UDP->cmos == 6) || (UDP->cmos == 5))
                        try = 64;       /* Only 48 actually useful */
                else
                        try = 32;       /* Only 24 actually useful */

                tmp = (char *)fd_dma_mem_alloc(1024 * try);
                if (!tmp && !floppy_track_buffer) {
                        try >>= 1;      /* buffer only one side */
                        INFBOUND(try, 16);
                        tmp = (char *)fd_dma_mem_alloc(1024 * try);
                }
                if (!tmp && !floppy_track_buffer)
                        fallback_on_nodma_alloc(&tmp, 2048 * try);
                if (!tmp && !floppy_track_buffer) {
                        DPRINT("Unable to allocate DMA memory\n");
                        goto out;
                }
                if (floppy_track_buffer) {
                        if (tmp)
                                fd_dma_mem_free((unsigned long)tmp, try * 1024);
                } else {
                        buffer_min = buffer_max = -1;
                        floppy_track_buffer = tmp;
                        max_buffer_sectors = try;
                }
        }

        new_dev = MINOR(bdev->bd_dev);
        UDRS->fd_device = new_dev;
        set_capacity(disks[drive], floppy_sizes[new_dev]);
        if (old_dev != -1 && old_dev != new_dev) {
                if (buffer_drive == drive)
                        buffer_track = -1;
        }

        if (UFDCS->rawcmd == 1)
                UFDCS->rawcmd = 2;

        if (!(mode & FMODE_NDELAY)) {
                if (mode & (FMODE_READ|FMODE_WRITE)) {
                        UDRS->last_checked = 0;
                        check_disk_change(bdev);
                        if (test_bit(FD_DISK_CHANGED_BIT, &UDRS->flags))
                                goto out;
                }
                res = -EROFS;
                if ((mode & FMODE_WRITE) &&
                    !test_bit(FD_DISK_WRITABLE_BIT, &UDRS->flags))
                        goto out;
        }
        mutex_unlock(&open_lock);
        mutex_unlock(&floppy_mutex);
        return 0;
out:
        if (UDRS->fd_ref < 0)
                UDRS->fd_ref = 0;
        else
                UDRS->fd_ref--;
        if (!UDRS->fd_ref)
                opened_bdev[drive] = NULL;
out2:
        mutex_unlock(&open_lock);
        mutex_unlock(&floppy_mutex);
        return res;
}

/*
 * Check if the disk has been changed or if a change has been faked.
 */
static unsigned int floppy_check_events(struct gendisk *disk,
                                        unsigned int clearing)
{
        int drive = (long)disk->private_data;

        if (test_bit(FD_DISK_CHANGED_BIT, &UDRS->flags) ||
            test_bit(FD_VERIFY_BIT, &UDRS->flags))
                return DISK_EVENT_MEDIA_CHANGE;

        if (time_after(jiffies, UDRS->last_checked + UDP->checkfreq)) {
                lock_fdc(drive, false);
                poll_drive(false, 0);
                process_fd_request();
        }

        if (test_bit(FD_DISK_CHANGED_BIT, &UDRS->flags) ||
            test_bit(FD_VERIFY_BIT, &UDRS->flags) ||
            test_bit(drive, &fake_change) ||
            drive_no_geom(drive))
                return DISK_EVENT_MEDIA_CHANGE;
        return 0;
}

/*
 * This implements "read block 0" for floppy_revalidate().
 * Needed for format autodetection, checking whether there is
 * a disk in the drive, and whether that disk is writable.
 */

static void floppy_rb0_complete(struct bio *bio, int err)
{
        complete((struct completion *)bio->bi_private);
}

static int __floppy_read_block_0(struct block_device *bdev)
{
        struct bio bio;
        struct bio_vec bio_vec;
        struct completion complete;
        struct page *page;
        size_t size;

        page = alloc_page(GFP_NOIO);
        if (!page) {
                process_fd_request();
                return -ENOMEM;
        }

        size = bdev->bd_block_size;
        if (!size)
                size = 1024;

        bio_init(&bio);
        bio.bi_io_vec = &bio_vec;
        bio_vec.bv_page = page;
        bio_vec.bv_len = size;
        bio_vec.bv_offset = 0;
        bio.bi_vcnt = 1;
        bio.bi_idx = 0;
        bio.bi_size = size;
        bio.bi_bdev = bdev;
        bio.bi_sector = 0;
        bio.bi_flags = BIO_QUIET;
        init_completion(&complete);
        bio.bi_private = &complete;
        bio.bi_end_io = floppy_rb0_complete;

        submit_bio(READ, &bio);
        process_fd_request();
        wait_for_completion(&complete);

        __free_page(page);

        return 0;
}

/* revalidate the floppy disk, i.e. trigger format autodetection by reading
 * the bootblock (block 0). "Autodetection" is also needed to check whether
 * there is a disk in the drive at all... Thus we also do it for fixed
 * geometry formats */
static int floppy_revalidate(struct gendisk *disk)
{
        int drive = (long)disk->private_data;
        int cf;
        int res = 0;

        if (test_bit(FD_DISK_CHANGED_BIT, &UDRS->flags) ||
            test_bit(FD_VERIFY_BIT, &UDRS->flags) ||
            test_bit(drive, &fake_change) ||
            drive_no_geom(drive)) {
                if (WARN(atomic_read(&usage_count) == 0,
                         "VFS: revalidate called on non-open device.\n"))
                        return -EFAULT;

                lock_fdc(drive, false);
                cf = (test_bit(FD_DISK_CHANGED_BIT, &UDRS->flags) ||
                      test_bit(FD_VERIFY_BIT, &UDRS->flags));
                if (!(cf || test_bit(drive, &fake_change) || drive_no_geom(drive))) {
                        process_fd_request();   /*already done by another thread */
                        return 0;
                }
                UDRS->maxblock = 0;
                UDRS->maxtrack = 0;
                if (buffer_drive == drive)
                        buffer_track = -1;
                clear_bit(drive, &fake_change);
                clear_bit(FD_DISK_CHANGED_BIT, &UDRS->flags);
                if (cf)
                        UDRS->generation++;
                if (drive_no_geom(drive)) {
                        /* auto-sensing */
                        res = __floppy_read_block_0(opened_bdev[drive]);
                } else {
                        if (cf)
                                poll_drive(false, FD_RAW_NEED_DISK);
                        process_fd_request();
                }
        }
        set_capacity(disk, floppy_sizes[UDRS->fd_device]);
        return res;
}

static const struct block_device_operations floppy_fops = {
        .owner                  = THIS_MODULE,
        .open                   = floppy_open,
        .release                = floppy_release,
        .ioctl                  = fd_ioctl,
        .getgeo                 = fd_getgeo,
        .check_events           = floppy_check_events,
        .revalidate_disk        = floppy_revalidate,
};

/*
 * Floppy Driver initialization
 * =============================
 */

/* Determine the floppy disk controller type */
/* This routine was written by David C. Niemi */
static char __init get_fdc_version(void)
{
        int r;

        output_byte(FD_DUMPREGS);       /* 82072 and better know DUMPREGS */
        if (FDCS->reset)
                return FDC_NONE;
        r = result();
        if (r <= 0x00)
                return FDC_NONE;        /* No FDC present ??? */
        if ((r == 1) && (reply_buffer[0] == 0x80)) {
                pr_info("FDC %d is an 8272A\n", fdc);
                return FDC_8272A;       /* 8272a/765 don't know DUMPREGS */
        }
        if (r != 10) {
                pr_info("FDC %d init: DUMPREGS: unexpected return of %d bytes.\n",
                        fdc, r);
                return FDC_UNKNOWN;
        }

        if (!fdc_configure()) {
                pr_info("FDC %d is an 82072\n", fdc);
                return FDC_82072;       /* 82072 doesn't know CONFIGURE */
        }

        output_byte(FD_PERPENDICULAR);
        if (need_more_output() == MORE_OUTPUT) {
                output_byte(0);
        } else {
                pr_info("FDC %d is an 82072A\n", fdc);
                return FDC_82072A;      /* 82072A as found on Sparcs. */
        }

        output_byte(FD_UNLOCK);
        r = result();
        if ((r == 1) && (reply_buffer[0] == 0x80)) {
                pr_info("FDC %d is a pre-1991 82077\n", fdc);
                return FDC_82077_ORIG;  /* Pre-1991 82077, doesn't know
                                         * LOCK/UNLOCK */
        }
        if ((r != 1) || (reply_buffer[0] != 0x00)) {
                pr_info("FDC %d init: UNLOCK: unexpected return of %d bytes.\n",
                        fdc, r);
                return FDC_UNKNOWN;
        }
        output_byte(FD_PARTID);
        r = result();
        if (r != 1) {
                pr_info("FDC %d init: PARTID: unexpected return of %d bytes.\n",
                        fdc, r);
                return FDC_UNKNOWN;
        }
        if (reply_buffer[0] == 0x80) {
                pr_info("FDC %d is a post-1991 82077\n", fdc);
                return FDC_82077;       /* Revised 82077AA passes all the tests */
        }
        switch (reply_buffer[0] >> 5) {
        case 0x0:
                /* Either a 82078-1 or a 82078SL running at 5Volt */
                pr_info("FDC %d is an 82078.\n", fdc);
                return FDC_82078;
        case 0x1:
                pr_info("FDC %d is a 44pin 82078\n", fdc);
                return FDC_82078;
        case 0x2:
                pr_info("FDC %d is a S82078B\n", fdc);
                return FDC_S82078B;
        case 0x3:
                pr_info("FDC %d is a National Semiconductor PC87306\n", fdc);
                return FDC_87306;
        default:
                pr_info("FDC %d init: 82078 variant with unknown PARTID=%d.\n",
                        fdc, reply_buffer[0] >> 5);
                return FDC_82078_UNKN;
        }
}                               /* get_fdc_version */

/* lilo configuration */

static void __init floppy_set_flags(int *ints, int param, int param2)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(default_drive_params); i++) {
                if (param)
                        default_drive_params[i].params.flags |= param2;
                else
                        default_drive_params[i].params.flags &= ~param2;