floppy.c 119 KB
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/*
 *  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.
 */

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

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

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

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

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

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

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

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

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

#define FLOPPY_SANITY_CHECK
#undef  FLOPPY_SILENT_DCL_CLEAR

#define REALLY_SLOW_IO

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

/* do print messages for unexpected interrupts */
static int print_unex = 1;
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/timer.h>
#include <linux/workqueue.h>
#define FDPATCHES
#include <linux/fdreg.h>

#include <linux/fd.h>
#include <linux/hdreg.h>

#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/bio.h>
#include <linux/string.h>
#include <linux/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/devfs_fs_kernel.h>
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#include <linux/platform_device.h>
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#include <linux/buffer_head.h>	/* for invalidate_buffers() */
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#include <linux/mutex.h>
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/*
 * PS/2 floppies have much slower step rates than regular floppies.
 * It's been recommended that take about 1/4 of the default speed
 * in some more extreme cases.
 */
static int slow_floppy;

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

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

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

static DEFINE_SPINLOCK(floppy_lock);
static struct completion device_release;

static unsigned short virtual_dma_port = 0x3f0;
irqreturn_t floppy_interrupt(int irq, void *dev_id, struct pt_regs *regs);
static int set_dor(int fdc, char mask, char data);
static void register_devfs_entries(int drive) __init;

#define K_64	0x10000		/* 64KB */

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

static int allowed_drive_mask = 0x33;

#include <asm/floppy.h>

static int irqdma_allocated;

#define DEVICE_NAME "floppy"

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

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

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

/* Dma Memory related stuff */

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

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

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

/* End dma memory related stuff */

static unsigned long fake_change;
static int initialising = 1;

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

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

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

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

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

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

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

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

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

#define SEL_DLY (2*HZ/100)

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

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

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

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

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

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

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

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

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

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

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

	{ 3680,23,2,80,0,0x1C,0x10,0xCF,0x00,"H1840" }, /* 29 1.84MB 3.5"   */
	{ 1600,10,2,80,0,0x25,0x02,0xDF,0x2E,"D800"  },	/* 30 800KB 3.5"    */
	{ 3200,20,2,80,0,0x1C,0x00,0xCF,0x2C,"H1600" }, /* 31 1.6MB 3.5"    */
};

#define SECTSIZE (_FD_SECTSIZE(*floppy))

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

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

static sector_t floppy_sizes[256];

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static char floppy_device_name[] = "floppy";

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

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

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

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

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

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

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

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

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

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

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

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

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

static int usage_count;

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

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

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

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

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

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

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

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

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

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

#ifdef FLOPPY_SANITY_CHECK

#define OLOGSIZE 20

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

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

static int output_log_pos;
#endif

#define current_reqD -1
#define MAXTIMEOUT -2

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

		unit = newdor & 0x3;
		if (!is_selected(olddor, unit) && is_selected(newdor, unit)) {
			drive = REVDRIVE(fdc, unit);
			UDRS->select_date = jiffies;
		}
	}
	/*
	 *      We should propagate failures to grab the resources back
	 *      nicely from here. Actually we ought to rewrite the fd
	 *      driver some day too.
	 */
	if (newdor & FLOPPY_MOTOR_MASK)
		floppy_grab_irq_and_dma();
	if (olddor & FLOPPY_MOTOR_MASK)
		floppy_release_irq_and_dma();
	return olddor;
}

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

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

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

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

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

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

		for (;;) {
			set_current_state(TASK_INTERRUPTIBLE);

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

			schedule();

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

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

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

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

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

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

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

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