Import 1.3.39

[davej-history.git] / drivers / block / ide.c

/*
 *  linux/drivers/block/ide.c   Version 5.17  Nov 3, 1995
 *
 *  Copyright (C) 1994, 1995  Linus Torvalds & authors (see below)
 */

/*
 * This is the multiple IDE interface driver, as evolved from hd.c.  
 * It supports up to four IDE interfaces, on one or more IRQs (usually 14 & 15).
 * There can be up to two drives per interface, as per the ATA-2 spec.
 *
 * Primary i/f:    ide0: major=3;  (hda)         minor=0; (hdb)         minor=64
 * Secondary i/f:  ide1: major=22; (hdc or hd1a) minor=0; (hdd or hd1b) minor=64
 * Tertiary i/f:   ide2: major=33; (hde)         minor=0; (hdf)         minor=64
 * Quaternary i/f: ide3: major=34; (hdg)         minor=0; (hdh)         minor=64
 * 
 * It is easy to extend ide.c to handle more than four interfaces:
 *
 *      Change the MAX_HWIFS constant in ide.h.
 * 
 *      Define some new major numbers (in major.h), and insert them into
 *      the ide_hwif_to_major table in ide.c.
 * 
 *      Fill in the extra values for the new interfaces into the two tables
 *      inside ide.c:  default_io_base[]  and  default_irqs[].
 * 
 *      Create the new request handlers by cloning "do_ide3_request()"
 *      for each new interface, and add them to the switch statement
 *      in the ide_init() function in ide.c.
 *
 *      Recompile, create the new /dev/ entries, and it will probably work.
 *
 *  From hd.c:
 *  |
 *  | It traverses the request-list, using interrupts to jump between functions.
 *  | As nearly all functions can be called within interrupts, we may not sleep.
 *  | Special care is recommended.  Have Fun!
 *  |
 *  | modified by Drew Eckhardt to check nr of hd's from the CMOS.
 *  |
 *  | Thanks to Branko Lankester, lankeste@fwi.uva.nl, who found a bug
 *  | in the early extended-partition checks and added DM partitions.
 *  |
 *  | Early work on error handling by Mika Liljeberg (liljeber@cs.Helsinki.FI).
 *  |
 *  | IRQ-unmask, drive-id, multiple-mode, support for ">16 heads",
 *  | and general streamlining by Mark Lord (mlord@bnr.ca).
 *
 *  October, 1994 -- Complete line-by-line overhaul for linux 1.1.x, by:
 *
 *      Mark Lord       (mlord@bnr.ca)                  (IDE Perf.Pkg)
 *      Delman Lee      (delman@mipg.upenn.edu)         ("Mr. atdisk2")
 *      Petri Mattila   (ptjmatti@kruuna.helsinki.fi)   (EIDE stuff)
 *      Scott Snyder    (snyder@fnald0.fnal.gov)        (ATAPI IDE cd-rom)
 *
 *  Maintained by Mark Lord (mlord@bnr.ca):  ide.c, ide.h, triton.c, hd.c, ..
 *
 *  This was a rewrite of just about everything from hd.c, though some original
 *  code is still sprinkled about.  Think of it as a major evolution, with 
 *  inspiration from lots of linux users, esp.  hamish@zot.apana.org.au
 *
 *  Version 1.0 ALPHA   initial code, primary i/f working okay
 *  Version 1.3 BETA    dual i/f on shared irq tested & working!
 *  Version 1.4 BETA    added auto probing for irq(s)
 *  Version 1.5 BETA    added ALPHA (untested) support for IDE cd-roms,
 *  ...
 *  Version 3.5         correct the bios_cyl field if it's too small
 *  (linux 1.1.76)       (to help fdisk with brain-dead BIOSs)
 *  Version 3.6         cosmetic corrections to comments and stuff
 *  (linux 1.1.77)      reorganise probing code to make it understandable
 *                      added halfway retry to probing for drive identification
 *                      added "hdx=noprobe" command line option
 *                      allow setting multmode even when identification fails
 *  Version 3.7         move set_geometry=1 from do_identify() to ide_init()
 *                      increase DRQ_WAIT to eliminate nuisance messages
 *                      wait for DRQ_STAT instead of DATA_READY during probing
 *                        (courtesy of Gary Thomas gary@efland.UU.NET)
 *  Version 3.8         fixed byte-swapping for confused Mitsumi cdrom drives
 *                      update of ide-cd.c from Scott, allows blocksize=1024
 *                      cdrom probe fixes, inspired by jprang@uni-duisburg.de
 *  Version 3.9         don't use LBA if lba_capacity looks funny
 *                      correct the drive capacity calculations
 *                      fix probing for old Seagates without IDE_ALTSTATUS_REG
 *                      fix byte-ordering for some NEC cdrom drives
 *  Version 3.10        disable multiple mode by default; was causing trouble
 *  Version 3.11        fix mis-identification of old WD disks as cdroms
 *  Version 3,12        simplify logic for selecting initial mult_count
 *                        (fixes problems with buggy WD drives)
 *  Version 3.13        remove excess "multiple mode disabled" messages
 *  Version 3.14        fix ide_error() handling of BUSY_STAT
 *                      fix byte-swapped cdrom strings (again.. arghh!)
 *                      ignore INDEX bit when checking the ALTSTATUS reg
 *  Version 3.15        add SINGLE_THREADED flag for use with dual-CMD i/f
 *                      ignore WRERR_STAT for non-write operations
 *                      added vlb_sync support for DC-2000A & others,
 *                       (incl. some Promise chips), courtesy of Frank Gockel
 *  Version 3.16        convert vlb_32bit and vlb_sync into runtime flags
 *                      add ioctls to get/set VLB flags (HDIO_[SG]ET_CHIPSET)
 *                      rename SINGLE_THREADED to SUPPORT_SERIALIZE,
 *                      add boot flag to "serialize" operation for CMD i/f
 *                      add optional support for DTC2278 interfaces,
 *                       courtesy of andy@cercle.cts.com (Dyan Wile).
 *                      add boot flag to enable "dtc2278" probe
 *                      add probe to avoid EATA (SCSI) interfaces,
 *                       courtesy of neuffer@goofy.zdv.uni-mainz.de.
 *  Version 4.00        tidy up verify_area() calls - heiko@colossus.escape.de
 *                      add flag to ignore WRERR_STAT for some drives
 *                       courtesy of David.H.West@um.cc.umich.edu
 *                      assembly syntax tweak to vlb_sync
 *                      removeable drive support from scuba@cs.tu-berlin.de
 *                      add transparent support for DiskManager-6.0x "Dynamic
 *                       Disk Overlay" (DDO), most of this in in genhd.c
 *                      eliminate "multiple mode turned off" message at boot
 *  Version 4.10        fix bug in ioctl for "hdparm -c3"
 *                      fix DM6:DDO support -- now works with LILO, fdisk, ...
 *                      don't treat some naughty WD drives as removeable
 *  Version 4.11        updated DM6 support using info provided by OnTrack
 *  Version 5.00        major overhaul, multmode setting fixed, vlb_sync fixed
 *                      added support for 3rd/4th/alternative IDE ports
 *                      created ide.h; ide-cd.c now compiles separate from ide.c
 *                      hopefully fixed infinite "unexpected_intr" from cdroms
 *                      zillions of other changes and restructuring
 *                      somehow reduced overall memory usage by several kB
 *                      probably slowed things down slightly, but worth it
 *  Version 5.01        AT LAST!!  Finally understood why "unexpected_intr"
 *                       was happening at various times/places:  whenever the
 *                       ide-interface's ctl_port was used to "mask" the irq,
 *                       it also would trigger an edge in the process of masking
 *                       which would result in a self-inflicted interrupt!!
 *                       (such a stupid way to build a hardware interrupt mask).
 *                       This is now fixed (after a year of head-scratching).
 *  Version 5.02        got rid of need for {enable,disable}_irq_list()
 *  Version 5.03        tune-ups, comments, remove "busy wait" from drive resets
 *                      removed PROBE_FOR_IRQS option -- no longer needed
 *                      OOOPS!  fixed "bad access" bug for 2nd drive on an i/f
 *  Version 5.04        changed "ira %d" to "irq %d" in DEBUG message
 *                      added more comments, cleaned up unexpected_intr()
 *                      OOOPS!  fixed null pointer problem in ide reset code
 *                      added autodetect for Triton chipset -- no effect yet
 *  Version 5.05        OOOPS!  fixed bug in revalidate_disk()
 *                      OOOPS!  fixed bug in ide_do_request()
 *                      added ATAPI reset sequence for cdroms
 *  Version 5.10        added Bus-Mastered DMA support for Triton Chipset
 *                      some (mostly) cosmetic changes
 *  Version 5.11        added ht6560b support by malafoss@snakemail.hut.fi
 *                      reworked PCI scanning code
 *                      added automatic RZ1000 detection/support
 *                      added automatic PCI CMD640 detection/support
 *                      added option for VLB CMD640 support
 *                      tweaked probe to find cdrom on hdb with disks on hda,hdc
 *  Version 5.12        some performance tuning
 *                      added message to alert user to bad /dev/hd[cd] entries
 *                      OOOPS!  fixed bug in atapi reset
 *                      driver now forces "serialize" again for all cmd640 chips
 *                      noticed REALLY_SLOW_IO had no effect, moved it to ide.c
 *                      made do_drive_cmd() into public ide_do_drive_cmd()
 *  Version 5.13        fixed typo ('B'), thanks to houston@boyd.geog.mcgill.ca
 *                      fixed ht6560b support
 *  Version 5.13b (sss) fix problem in calling ide_cdrom_setup()
 *                      don't bother invalidating nonexistent partitions
 *  Version 5.14        fixes to cmd640 support.. maybe it works now(?)
 *                      added & tested full EZ-DRIVE support -- don't use LILO!
 *                      don't enable 2nd CMD640 PCI port during init - conflict
 *  Version 5.15        bug fix in init_cmd640_vlb()
 *                      bug fix in interrupt sharing code
 *  Version 5.16        ugh.. fix "serialize" support, broken in 5.15
 *                      remove "Huh?" from cmd640 code
 *                      added qd6580 interface speed select from Colten Edwards
 *  Version 5.17        kludge around bug in BIOS32 on Intel triton motherboards
 *
 *  Driver compile-time options are in ide.h
 *
 *  To do, in likely order of completion:
 *      - add ALI M1443/1445 chipset support from derekn@vw.ece.cmu.edu
 *      - add Promise Caching controller support from peterd@pnd-pc.demon.co.uk
 *      - add ioctls to get/set interface timings on various interfaces
 *      - modify kernel to obtain BIOS geometry for drives on 2nd/3rd/4th i/f
 *      - improved CMD support:  handed this off to someone else
 *      - find someone to work on IDE *tape drive* support
 */

#undef REALLY_SLOW_IO           /* most systems can safely undef this */

#include <linux/config.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/timer.h>
#include <linux/mm.h>
#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/major.h>
#include <linux/blkdev.h>
#include <linux/errno.h>
#include <linux/hdreg.h>
#include <linux/genhd.h>
#include <linux/malloc.h>

#include <asm/byteorder.h>
#include <asm/irq.h>
#include <asm/segment.h>
#include <asm/io.h>

#ifdef CONFIG_PCI
#include <linux/bios32.h>
#include <linux/pci.h>
#endif /* CONFIG_PCI */

#include "ide.h"

       ide_hwif_t       ide_hwifs[MAX_HWIFS];           /* hwif info */
static ide_hwgroup_t    *irq_to_hwgroup [16];
static const byte       ide_hwif_to_major[MAX_HWIFS]   = {IDE0_MAJOR, IDE1_MAJOR, IDE2_MAJOR, IDE3_MAJOR};

static const unsigned short default_io_base[MAX_HWIFS] = {0x1f0, 0x170, 0x1e8, 0x168};
static const byte       default_irqs[MAX_HWIFS]     = {14, 15, 11, 10};
static int              serialized = 0;         /* "serialize" option */
static int              disallow_unmask = 0;    /* for buggy hardware */

#if (DISK_RECOVERY_TIME > 0)
/*
 * For really screwy hardware (hey, at least it *can* be used with Linux)
 * we can enforce a minimum delay time between successive operations.
 */
static unsigned long read_timer(void)
{
        unsigned long t, flags;
        int i;

        save_flags(flags);
        cli();
        t = jiffies * 11932;
        outb_p(0, 0x43);
        i = inb_p(0x40);
        i |= inb(0x40) << 8;
        restore_flags(flags);
        return (t - i);
}

void ide_set_recovery_timer (ide_hwif_t *hwif)
{
        hwif->last_time = read_timer();
}
#endif /* DISK_RECOVERY_TIME */

/*
 * init_ide_data() sets reasonable default values into all fields
 * of all instances of the hwifs and drives, but only on the first call.
 * Subsequent calls have no effect (they don't wipe out anything).
 *
 * This routine is normally called at driver initialization time,
 * but may also be called MUCH earlier during kernel "command-line"
 * parameter processing.  As such, we cannot depend on any other parts
 * of the kernel (such as memory allocation) to be functioning yet.
 *
 * This is too bad, as otherwise we could dynamically allocate the
 * ide_drive_t structs as needed, rather than always consuming memory
 * for the max possible number (MAX_HWIFS * MAX_DRIVES) of them.
 */
#define MAGIC_COOKIE 0x12345678
static void init_ide_data (void)
{
        byte *p;
        unsigned int h, unit;
        static unsigned long magic_cookie = MAGIC_COOKIE;

        if (magic_cookie != MAGIC_COOKIE)
                return;         /* already initialized */
        magic_cookie = 0;

        for (h = 0; h < 16; ++h)
                 irq_to_hwgroup[h] = NULL;

        /* bulk initialize hwif & drive info with zeros */
        p = ((byte *) ide_hwifs) + sizeof(ide_hwifs);
        do {
                *--p = 0;
        } while (p > (byte *) ide_hwifs);

        for (h = 0; h < MAX_HWIFS; ++h) {
                ide_hwif_t *hwif = &ide_hwifs[h];

                /* fill in any non-zero initial values */
                hwif->noprobe   = (h > 1);
                hwif->io_base   = default_io_base[h];
                hwif->ctl_port  = hwif->io_base ? hwif->io_base+0x206 : 0x000;
#ifdef CONFIG_BLK_DEV_HD
                if (hwif->io_base == HD_DATA)
                        hwif->noprobe = 1; /* may be overriden by ide_setup() */
#endif /* CONFIG_BLK_DEV_HD */
                hwif->major     = ide_hwif_to_major[h];
                hwif->name[0]   = 'i';
                hwif->name[1]   = 'd';
                hwif->name[2]   = 'e';
                hwif->name[3]   = '0' + h;

                for (unit = 0; unit < MAX_DRIVES; ++unit) {
                        ide_drive_t *drive = &hwif->drives[unit];

                        /* fill in any non-zero initial values */
                        drive->select.all               = (unit<<4)|0xa0;
                        drive->hwif                     = hwif;
                        drive->ctl                      = 0x08;
                        drive->ready_stat               = READY_STAT;
                        drive->bad_wstat                = BAD_W_STAT;
                        drive->special.b.recalibrate    = 1;
                        drive->special.b.set_geometry   = 1;
                        drive->name[0]                  = 'h';
                        drive->name[1]                  = 'd';
                        drive->name[2]                  = 'a' + (h * MAX_DRIVES) + unit;
                }
        }
}

#define VLB_SYNC 1
/*
 * Some localbus EIDE interfaces require a special access sequence
 * when using 32-bit I/O instructions to transfer data.  We call this
 * the "vlb_sync" sequence, which consists of three successive reads
 * of the sector count register location, with interrupts disabled
 * to ensure that the reads all happen together.
 */
static inline void do_vlb_sync (unsigned short port) {
        (void) inb (port);
        (void) inb (port);
        (void) inb (port);
}

/*
 * This is used for most PIO data transfers *from* the IDE interface
 */
void ide_input_data (ide_drive_t *drive, void *buffer, unsigned int wcount)
{
        unsigned short io_base  = HWIF(drive)->io_base;
        unsigned short data_reg = io_base+IDE_DATA_OFFSET;

        if (drive->vlb_32bit) {
#ifdef VLB_SYNC
                if (drive->vlb_sync) {
                        cli();
                        do_vlb_sync(io_base+IDE_NSECTOR_OFFSET);
                        insl(data_reg, buffer, wcount);
                        if (drive->unmask)
                                sti();
                } else
#endif /* VLB_SYNC */
                        insl(data_reg, buffer, wcount);
        } else
                insw(data_reg, buffer, wcount<<1);
}

/*
 * This is used for most PIO data transfers *to* the IDE interface
 */
void ide_output_data (ide_drive_t *drive, void *buffer, unsigned int wcount)
{
        unsigned short io_base  = HWIF(drive)->io_base;
        unsigned short data_reg = io_base+IDE_DATA_OFFSET;

        if (drive->vlb_32bit) {
#ifdef VLB_SYNC
                if (drive->vlb_sync) {
                        cli();
                        do_vlb_sync(io_base+IDE_NSECTOR_OFFSET);
                        outsl(data_reg, buffer, wcount);
                        if (drive->unmask)
                                sti();
                } else
#endif /* VLB_SYNC */
                        outsl(data_reg, buffer, wcount);
        } else
                outsw(data_reg, buffer, wcount<<1);
}

#if SUPPORT_HT6560B
/*
 * This routine handles interface switching for the peculiar hardware design
 * on the F.G.I./Holtek HT-6560B VLB IDE interface.
 * The HT-6560B can only enable one IDE port at a time, and requires a
 * silly sequence (below) whenever we switch between primary and secondary.
 *
 * Apparently, systems with multiple CMD640 chips may need something similar..
 *
 * This algorithm courtesy of malafoss@snakemail.hut.fi
 */

void ide_hwif_select (ide_hwif_t *hwif)
{
        static byte current_select = 0;

        if (hwif->select != current_select) {
                unsigned long flags;
                save_flags (flags);
                cli();
                current_select = hwif->select;
                (void) inb(0x3e6);
                (void) inb(0x3e6);
                (void) inb(0x3e6);
                (void) inb(0x3e6);
                outb(current_select,0x3e6);
                restore_flags (flags);
        }
}
#endif /* SUPPORT_HT6560B */

/*
 * This should get invoked any time we exit the driver to
 * wait for an interrupt response from a drive.  handler() points
 * at the appropriate code to handle the next interrupt, and a
 * timer is started to prevent us from waiting forever in case
 * something goes wrong (see the timer_expiry() handler later on).
 */
void ide_set_handler (ide_drive_t *drive, ide_handler_t *handler)
{
        ide_hwgroup_t *hwgroup = HWGROUP(drive);
#ifdef DEBUG
        if (hwgroup->handler != NULL)
                printk("%s: ide_set_handler: old handler not null\n", drive->name);
#endif
        hwgroup->handler       = handler;
        hwgroup->timer.expires = jiffies + WAIT_CMD;
        add_timer(&(hwgroup->timer));
}

/*
 * lba_capacity_is_ok() performs a sanity check on the claimed "lba_capacity"
 * value for this drive (from its reported identification information).
 *
 * Returns:     1 if lba_capacity looks sensible
 *              0 otherwise
 */
static int lba_capacity_is_ok (struct hd_driveid *id)
{
        unsigned long lba_sects   = id->lba_capacity;
        unsigned long chs_sects   = id->cyls * id->heads * id->sectors;
        unsigned long _10_percent = chs_sects / 10;

        /* perform a rough sanity check on lba_sects:  within 10% is "okay" */
        if ((lba_sects - chs_sects) < _10_percent)
                return 1;       /* lba_capacity is good */

        /* some drives have the word order reversed */
        lba_sects = (lba_sects << 16) | (lba_sects >> 16);
        if ((lba_sects - chs_sects) < _10_percent) {
                id->lba_capacity = lba_sects;   /* fix it */
                return 1;       /* lba_capacity is (now) good */
        }
        return 0;       /* lba_capacity value is bad */
}

/*
 * current_capacity() returns the capacity (in sectors) of a drive
 * according to its current geometry/LBA settings.
 */
static unsigned long current_capacity (ide_drive_t  *drive)
{
        struct hd_driveid *id = drive->id;
        unsigned long capacity;

        if (!drive->present)
                return 0;
        if (drive->media != disk)
                return 0x1fffff;        /* cdrom */
        /* Determine capacity, and use LBA if the drive properly supports it */
        if (id != NULL && (id->capability & 2) && lba_capacity_is_ok(id)) {
                drive->select.b.lba = 1;
                capacity = id->lba_capacity;
        } else {
                drive->select.b.lba = 0;
                capacity = drive->cyl * drive->head * drive->sect;
        }
        return (capacity - drive->sect0);
}

/*
 * ide_geninit() is called exactly *once* for each major, from genhd.c,
 * at the beginning of the initial partition check for the drives.
 */
static void ide_geninit (struct gendisk *gd)
{
        unsigned int unit;
        ide_hwif_t *hwif = gd->real_devices;

        for (unit = 0; unit < gd->nr_real; ++unit) {
                ide_drive_t *drive = &hwif->drives[unit];
#ifdef CONFIG_BLK_DEV_IDECD
                if (drive->present && drive->media == cdrom)
                        ide_cdrom_setup(drive);
#endif /* CONFIG_BLK_DEV_IDECD */
                drive->part[0].nr_sects = current_capacity(drive);
                if (!drive->present || drive->media != disk) {
                        drive->part[0].start_sect = -1; /* skip partition check */
                }
        }
        /*
         * The partition check in genhd.c needs this string to identify
         * our minor devices by name for display purposes.
         * Note that doing this will prevent us from working correctly
         * if ever called a second time for this major (never happens).
         */
        gd->real_devices = hwif->drives[0].name;  /* name of first drive */
}

/*
 * init_gendisk() (as opposed to ide_geninit) is called for each major device,
 * after probing for drives, to allocate partition tables and other data
 * structures needed for the routines in genhd.c.  ide_geninit() gets called
 * somewhat later, during the partition check.
 */
static void init_gendisk (ide_hwif_t *hwif)
{
        struct gendisk *gd;
        unsigned int unit, units, minors;
        int *bs;

        /* figure out maximum drive number on the interface */
        for (units = MAX_DRIVES; units > 0; --units) {
                if (hwif->drives[units-1].present)
                        break;
        }
        minors    = units * (1<<PARTN_BITS);
        gd        = kmalloc (sizeof(struct gendisk), GFP_KERNEL);
        gd->sizes = kmalloc (minors * sizeof(int), GFP_KERNEL);
        gd->part  = kmalloc (minors * sizeof(struct hd_struct), GFP_KERNEL);
        bs        = kmalloc (minors*sizeof(int), GFP_KERNEL);

        /* cdroms and msdos f/s are examples of non-1024 blocksizes */
        blksize_size[hwif->major] = bs;
        for (unit = 0; unit < minors; ++unit)
                *bs++ = BLOCK_SIZE;

        for (unit = 0; unit < units; ++unit)
                hwif->drives[unit].part = &gd->part[unit << PARTN_BITS];

        gd->major       = hwif->major;          /* our major device number */
        gd->major_name  = IDE_MAJOR_NAME;       /* treated special in genhd.c */
        gd->minor_shift = PARTN_BITS;           /* num bits for partitions */
        gd->max_p       = 1<<PARTN_BITS;        /* 1 + max partitions / drive */
        gd->max_nr      = units;                /* max num real drives */
        gd->nr_real     = units;                /* current num real drives */
        gd->init        = ide_geninit;          /* initialization function */
        gd->real_devices= hwif;                 /* ptr to internal data */

        gd->next = gendisk_head;                /* link new major into list */
        hwif->gd = gendisk_head = gd;
}

static void unexpected_intr (int, ide_hwgroup_t *);
/*
 * reset_ihandler() is a dummy interrupt handler which we install during
 * an ide interface reset operation.  This prevents other devices in the
 * same hwgroup from being serviced while we play around with shared resources.
 * If it ever gets invoked, we call unexpected_intr(), which treats the event
 * the same as a timer_expiry().
 */
static void reset_ihandler (ide_drive_t *drive)
{
        unsigned long flags;

        save_flags(flags);
        cli();
        unexpected_intr (HWIF(drive)->irq, HWGROUP(drive));
        restore_flags(flags);
}

/*
 * start_reset_timer() sets up a timer event for 50ms in the future,
 * to poll for completion of an ide reset operation (no interrupt to help us).
 */
static void start_reset_timer (ide_hwif_t *hwif)
{
        ide_hwgroup_t *hwgroup = hwif->hwgroup;

        hwgroup->reset_timeout = jiffies + WAIT_WORSTCASE; /* max waiting time */
        hwgroup->handler = &reset_ihandler;             /* dummy irq handler */
        hwgroup->timer.expires = jiffies + (HZ/20);     /* polling interval */
        add_timer(&(hwgroup->timer));
}

#ifdef CONFIG_BLK_DEV_IDECD
/*
 * atapi_reset_handler() gets invoked to poll the interface for completion every 50ms
 * during an atapi drive reset operation. If the drive has not yet responded,
 * and we have not yet hit our maximum waiting time, then the timer is restarted
 * for another 50ms.
 *
 * Returns 1 if waiting for another 50ms, returns 0 otherwise.
 */
static int atapi_reset_handler (ide_hwgroup_t *hwgroup)
{
        ide_hwif_t *hwif = hwgroup->hwif;
        ide_drive_t *drive = hwgroup->drive;
        byte stat;

        OUT_BYTE (drive->select.all, IDE_SELECT_REG);
        udelay (10);

        if (!OK_STAT(stat=GET_STAT(), 0, BUSY_STAT)) {
                if (jiffies < hwgroup->reset_timeout) {
                        start_reset_timer (hwif);
                        return 1;
                }
                printk("%s: ATAPI reset timed-out, status=0x%02x\n", drive->name, stat);
                return ide_do_reset (drive);    /* do it the old fashioned way */
        }
        hwgroup->doing_atapi_reset = 0;
        hwgroup->handler = NULL;        /* allow new requests to be processed */
        hwgroup->reset_timeout = 0;     /* signal end of ide reset operation */
        printk("%s: ATAPI reset complete\n", drive->name);
        return 0;
}
#endif /* CONFIG_BLK_DEV_IDECD */

/*
 * reset_handler() gets invoked to poll the interface for completion every 50ms
 * during an ide reset operation. If the drives have not yet responded,
 * and we have not yet hit our maximum waiting time, then the timer is restarted
 * for another 50ms.
 *
 * Returns 1 if waiting for another 50ms, returns 0 otherwise.
 */
static int reset_handler (ide_hwgroup_t *hwgroup)
{
        ide_hwif_t *hwif = hwgroup->hwif;
        ide_drive_t *drive = hwgroup->drive;
        byte tmp;

#ifdef CONFIG_BLK_DEV_IDECD
        if (hwgroup->doing_atapi_reset)
                return atapi_reset_handler(hwgroup);
#endif /* CONFIG_BLK_DEV_IDECD */

        if (!OK_STAT(tmp=GET_STAT(), 0, BUSY_STAT)) {
                if (jiffies < hwgroup->reset_timeout) {
                        start_reset_timer (hwif);
                        return 1;
                }
                printk("%s: reset timed-out, status=0x%02x\n", hwif->name, tmp);
        } else  {
                printk("%s: reset: ", hwif->name);
                if ((tmp = GET_ERR()) == 1)
                        printk("success\n");
                else {
                        printk("master: ");
                        switch (tmp & 0x7f) {
                                case 1: printk("passed");
                                        break;
                                case 2: printk("formatter device error");
                                        break;
                                case 3: printk("sector buffer error");
                                        break;
                                case 4: printk("ECC circuitry error");
                                        break;
                                case 5: printk("controlling MPU error");
                                        break;
                                default:printk("error (0x%02x?)", tmp);
                        }
                        if (tmp & 0x80)
                                printk("; slave: failed");
                        printk("\n");
                }
        }
        hwgroup->handler = NULL;        /* allow new requests to be processed */
        hwgroup->reset_timeout = 0;     /* signal end of ide reset operation */
        return 0;
}

/*
 * ide_do_reset() attempts to recover a confused drive by resetting it.
 * Unfortunately, resetting a disk drive actually resets all devices on
 * the same interface, so it can really be thought of as resetting the
 * interface rather than resetting the drive.
 *
 * ATAPI devices have their own reset mechanism which allows them to be
 * individually reset without clobbering other devices on the same interface.
 *
 * Unfortunately, the IDE interface does not generate an interrupt to let
 * us know when the reset operation has finished, so we must poll for this.
 * Equally poor, though, is the fact that this may a very long time to complete,
 * (up to 30 seconds worstcase).  So, instead of busy-waiting here for it,
 * we set a timer to poll at 50ms intervals.
 */
int ide_do_reset (ide_drive_t *drive)
{
        unsigned int unit;
        unsigned long flags;
        ide_hwif_t *hwif = HWIF(drive);
        ide_hwgroup_t *hwgroup = HWGROUP(drive);

        save_flags(flags);
        cli();          /* Why ? */

#ifdef CONFIG_BLK_DEV_IDECD
        /* For an ATAPI device, first try an ATAPI SRST. */
        if (drive->media == cdrom) {
                if (!hwgroup->doing_atapi_reset) {
                        hwgroup->doing_atapi_reset = 1;
                        if (!drive->keep_settings)
                                drive->unmask = 0;
                        OUT_BYTE (drive->select.all, IDE_SELECT_REG);
                        udelay (20);
                        OUT_BYTE (WIN_SRST, IDE_COMMAND_REG);
                        hwgroup->reset_timeout = jiffies + WAIT_WORSTCASE;
                        start_reset_timer (hwif); /* begin periodic polling */
                        restore_flags (flags);
                        return 1;
                }
        }
        hwgroup->doing_atapi_reset = 0;
#endif /* CONFIG_BLK_DEV_IDECD */

        /*
         * First, reset any device state data we were maintaining
         * for any of the drives on this interface.
         */
        for (unit = 0; unit < MAX_DRIVES; ++unit) {
                ide_drive_t *rdrive = &hwif->drives[unit];
                rdrive->special.b.set_geometry = 1;
                rdrive->special.b.recalibrate  = 1;
                rdrive->special.b.set_multmode = 0;
                if (OK_TO_RESET_CONTROLLER)
                        rdrive->mult_count = 0;
                if (!rdrive->keep_settings) {
                        rdrive->mult_req = 0;
                        rdrive->unmask = 0;
                }
                if (rdrive->mult_req != rdrive->mult_count)
                        rdrive->special.b.set_multmode = 1;
        }

#if OK_TO_RESET_CONTROLLER
        /*
         * Note that we also set nIEN while resetting the device,
         * to mask unwanted interrupts from the interface during the reset.
         * However, due to the design of PC hardware, this will cause an
         * immediate interrupt due to the edge transition it produces.
         * This single interrupt gives us a "fast poll" for drives that
         * recover from reset very quickly, saving us the first 50ms wait time.
         */
        OUT_BYTE(drive->ctl|6,IDE_CONTROL_REG); /* set SRST and nIEN */
        udelay(5);                      /* more than enough time */
        OUT_BYTE(drive->ctl|2,IDE_CONTROL_REG); /* clear SRST, leave nIEN */
        hwgroup->reset_timeout = jiffies + WAIT_WORSTCASE;
        start_reset_timer (hwif);       /* begin periodic polling */
#endif  /* OK_TO_RESET_CONTROLLER */

        restore_flags (flags);
        return OK_TO_RESET_CONTROLLER;  /* 1 = we are waiting, 0 = done */
}

/*
 * Clean up after success/failure of an explicit (ioctl) drive cmd
 */
static void end_drive_cmd (ide_drive_t *drive, byte stat, byte err)
{
        unsigned long flags;
        struct request *rq = HWGROUP(drive)->rq;
        byte *args = (byte *) rq->buffer;

        rq->errors = !OK_STAT(stat,READY_STAT,BAD_STAT);
        if (args) {
                args[0] = stat;
                args[1] = err;
                args[2] = IN_BYTE(IDE_NSECTOR_REG);
        }
        save_flags(flags);
        cli();
        up(rq->sem);
        HWGROUP(drive)->rq = NULL;
        restore_flags(flags);
}

/*
 * Error reporting, in human readable form (luxurious, but a memory hog).
 */
byte ide_dump_status (ide_drive_t *drive, const char *msg, byte stat)
{
        unsigned long flags;
        byte err = 0;

        save_flags (flags);
        sti();
        printk("%s: %s: status=0x%02x", drive->name, msg, stat);
#if FANCY_STATUS_DUMPS
        if (drive->media == disk) {
                printk(" { ");
                if (stat & BUSY_STAT)
                        printk("Busy ");
                else {
                        if (stat & READY_STAT)  printk("DriveReady ");
                        if (stat & WRERR_STAT)  printk("DeviceFault ");
                        if (stat & SEEK_STAT)   printk("SeekComplete ");
                        if (stat & DRQ_STAT)    printk("DataRequest ");
                        if (stat & ECC_STAT)    printk("CorrectedError ");
                        if (stat & INDEX_STAT)  printk("Index ");
                        if (stat & ERR_STAT)    printk("Error ");
                }
                printk("}");
        }
#endif  /* FANCY_STATUS_DUMPS */
        printk("\n");
        if ((stat & (BUSY_STAT|ERR_STAT)) == ERR_STAT) {
                err = GET_ERR();
                printk("%s: %s: error=0x%02x", drive->name, msg, err);
#if FANCY_STATUS_DUMPS
                if (drive->media == disk) {
                        printk(" { ");
                        if (err & BBD_ERR)      printk("BadSector ");
                        if (err & ECC_ERR)      printk("UncorrectableError ");
                        if (err & ID_ERR)       printk("SectorIdNotFound ");
                        if (err & ABRT_ERR)     printk("DriveStatusError ");
                        if (err & TRK0_ERR)     printk("TrackZeroNotFound ");
                        if (err & MARK_ERR)     printk("AddrMarkNotFound ");
                        printk("}");
                        if (err & (BBD_ERR|ECC_ERR|ID_ERR|MARK_ERR)) {
                                byte cur = IN_BYTE(IDE_SELECT_REG);
                                if (cur & 0x40) {       /* using LBA? */
                                        printk(", LBAsect=%ld", (unsigned long)
                                         ((cur&0xf)<<24)
                                         |(IN_BYTE(IDE_HCYL_REG)<<16)
                                         |(IN_BYTE(IDE_LCYL_REG)<<8)
                                         | IN_BYTE(IDE_SECTOR_REG));
                                } else {
                                        printk(", CHS=%d/%d/%d",
                                         (IN_BYTE(IDE_HCYL_REG)<<8) +
                                          IN_BYTE(IDE_LCYL_REG),
                                          cur & 0xf,
                                          IN_BYTE(IDE_SECTOR_REG));
                                }
                                if (HWGROUP(drive)->rq)
                                        printk(", sector=%ld", HWGROUP(drive)->rq->sector);
                        }
                }
#endif  /* FANCY_STATUS_DUMPS */
                printk("\n");
        }
        restore_flags (flags);
        return err;
}

/*
 * try_to_flush_leftover_data() is invoked in response to a drive
 * unexpectedly having its DRQ_STAT bit set.  As an alternative to
 * resetting the drive, this routine tries to clear the condition
 * by read a sector's worth of data from the drive.  Of course,
 * this may not help if the drive is *waiting* for data from *us*.
 */
static void try_to_flush_leftover_data (ide_drive_t *drive)
{
        int i = (drive->mult_count ? drive->mult_count : 1) * SECTOR_WORDS;

        while (i > 0) {
                unsigned long buffer[16];
                unsigned int wcount = (i > 16) ? 16 : i;
                i -= wcount;
                ide_input_data (drive, buffer, wcount);
        }
}

/*
 * ide_error() takes action based on the error returned by the controller.
 *
 * Returns 1 if an ide reset operation has been initiated, in which case
 * the caller MUST simply return from the driver (through however many levels).
 * Returns 0 otherwise.
 */
int ide_error (ide_drive_t *drive, const char *msg, byte stat)
{
        struct request *rq;
        byte err;

        err = ide_dump_status(drive, msg, stat);
        if ((rq = HWGROUP(drive)->rq) == NULL || drive == NULL)
                return 0;
        if (rq->cmd == IDE_DRIVE_CMD) { /* never retry an explicit DRIVE_CMD */
                end_drive_cmd(drive, stat, err);
                return 0;
        }
        if (stat & BUSY_STAT) {         /* other bits are useless when BUSY */
                rq->errors |= ERROR_RESET;
        } else {
                if (drive->media == disk && (stat & ERR_STAT)) {
                        /* err has different meaning on cdrom */
                        if (err & BBD_ERR)              /* retries won't help this! */
                                rq->errors = ERROR_MAX;
                        else if (err & TRK0_ERR)        /* help it find track zero */
                                rq->errors |= ERROR_RECAL;
                }
                if ((stat & DRQ_STAT) && rq->cmd != WRITE)
                        try_to_flush_leftover_data(drive);
        }
        if (GET_STAT() & (BUSY_STAT|DRQ_STAT))
                rq->errors |= ERROR_RESET;      /* Mmmm.. timing problem */

#ifdef CONFIG_BLK_DEV_TRITON
        if (rq->errors > 3 && drive->using_dma) {       /* DMA troubles? */
                drive->using_dma = 0;
                printk("%s: DMA disabled\n", drive->name);
                --rq->errors;
                return 0;
        }
#endif /* CONFIG_BLK_DEV_TRITON */
        if (rq->errors >= ERROR_MAX)
                ide_end_request(0, HWGROUP(drive));
        else {
                if ((rq->errors & ERROR_RESET) == ERROR_RESET) {
                        ++rq->errors;
                        return ide_do_reset(drive);
                } else if ((rq->errors & ERROR_RECAL) == ERROR_RECAL)
                        drive->special.b.recalibrate = 1;
                ++rq->errors;
        }
        return 0;
}

/*
 * read_intr() is the handler for disk read/multread interrupts
 */
static void read_intr (ide_drive_t *drive)
{
        byte stat;
        int i;
        unsigned int msect, nsect;
        struct request *rq;

        if (!OK_STAT(stat=GET_STAT(),DATA_READY,BAD_R_STAT)) {
                sti();
                if (!ide_error(drive, "read_intr", stat))
                        IDE_DO_REQUEST;
                return;
        }
        msect = drive->mult_count;
read_next:
        rq = HWGROUP(drive)->rq;
        if (msect) {
                if ((nsect = rq->current_nr_sectors) > msect)
                        nsect = msect;
                msect -= nsect;
        } else
                nsect = 1;
        ide_input_data(drive, rq->buffer, nsect * SECTOR_WORDS);
#ifdef DEBUG
        printk("%s:  read: sectors(%ld-%ld), buffer=0x%08lx, remaining=%ld\n",
                drive->name, rq->sector, rq->sector+nsect-1,
                (unsigned long) rq->buffer+(nsect<<9), rq->nr_sectors-nsect);
#endif
        rq->sector += nsect;
        rq->buffer += nsect<<9;
        rq->errors = 0;
        i = (rq->nr_sectors -= nsect);
        if ((rq->current_nr_sectors -= nsect) <= 0)
                ide_end_request(1, HWGROUP(drive));
        if (i > 0) {
                if (msect)
                        goto read_next;
                ide_set_handler (drive, &read_intr);
                return;
        }
        IDE_DO_REQUEST;
}

/*
 * write_intr() is the handler for disk write interrupts
 */
static void write_intr (ide_drive_t *drive)
{
        byte stat;
        int i;
        struct request *rq = HWGROUP(drive)->rq;

        if (OK_STAT(stat=GET_STAT(),DRIVE_READY,drive->bad_wstat)) {
#ifdef DEBUG
                printk("%s: write: sector %ld, buffer=0x%08lx, remaining=%ld\n",
                        drive->name, rq->sector, (unsigned long) rq->buffer,
                        rq->nr_sectors-1);
#endif
                if ((rq->nr_sectors == 1) ^ ((stat & DRQ_STAT) != 0)) {
                        rq->sector++;
                        rq->buffer += 512;
                        rq->errors = 0;
                        i = --rq->nr_sectors;
                        --rq->current_nr_sectors;
                        if (rq->current_nr_sectors <= 0)
                                ide_end_request(1, HWGROUP(drive));
                        if (i > 0) {
                                ide_output_data (drive, rq->buffer, SECTOR_WORDS);
                                ide_set_handler (drive, &write_intr);
                                return;
                        }
                        IDE_DO_REQUEST;
                        return;
                }
        }
        sti();
        if (!ide_error(drive, "write_intr", stat))
                IDE_DO_REQUEST;
}

/*
 * multwrite() transfers a block of one or more sectors of data to a drive
 * as part of a disk multwrite operation.  
 */
static void multwrite (ide_drive_t *drive)
{
        struct request *rq = &HWGROUP(drive)->wrq;
        unsigned int mcount = drive->mult_count;

        do {
                unsigned int nsect = rq->current_nr_sectors;
                if (nsect > mcount)
                        nsect = mcount;
                mcount -= nsect;

                ide_output_data(drive, rq->buffer, nsect<<7);
#ifdef DEBUG
                printk("%s: multwrite: sector %ld, buffer=0x%08lx, count=%d, remaining=%ld\n",
                        drive->name, rq->sector, (unsigned long) rq->buffer,
                        nsect, rq->nr_sectors - nsect);
#endif
                if ((rq->nr_sectors -= nsect) <= 0)
                        break;
                if ((rq->current_nr_sectors -= nsect) == 0) {
                        if ((rq->bh = rq->bh->b_reqnext) != NULL) {
                                rq->current_nr_sectors = rq->bh->b_size>>9;
                                rq->buffer             = rq->bh->b_data;
                        } else {
                                panic("%s: buffer list corrupted\n", drive->name);
                                break;
                        }
                } else {
                        rq->buffer += nsect << 9;
                }
        } while (mcount);
}

/*
 * write_intr() is the handler for disk multwrite interrupts
 */
static void multwrite_intr (ide_drive_t *drive)
{
        byte stat;
        int i;
        struct request *rq = &HWGROUP(drive)->wrq;

        if (OK_STAT(stat=GET_STAT(),DRIVE_READY,drive->bad_wstat)) {
                if (stat & DRQ_STAT) {
                        if (rq->nr_sectors) {
                                multwrite(drive);
                                ide_set_handler (drive, &multwrite_intr);
                                return;
                        }
                } else {
                        if (!rq->nr_sectors) {  /* all done? */
                                rq = HWGROUP(drive)->rq;
                                for (i = rq->nr_sectors; i > 0;){
                                        i -= rq->current_nr_sectors;
                                        ide_end_request(1, HWGROUP(drive));
                                }
                                IDE_DO_REQUEST;
                                return;
                        }
                }
        }
        sti();
        if (!ide_error(drive, "multwrite_intr", stat))
                IDE_DO_REQUEST;
}

/*
 * Issue a simple drive command
 * The drive must be selected beforehand.
 */
static void ide_cmd(ide_drive_t *drive, byte cmd, byte nsect, ide_handler_t *handler)
{
        ide_set_handler (drive, handler);
        OUT_BYTE(drive->ctl,IDE_CONTROL_REG);
        OUT_BYTE(nsect,IDE_NSECTOR_REG);
        OUT_BYTE(cmd,IDE_COMMAND_REG);
}

/*
 * set_multmode_intr() is invoked on completion of a WIN_SETMULT cmd.
 */
static void set_multmode_intr (ide_drive_t *drive)
{
        byte stat = GET_STAT();

        sti();
        if (OK_STAT(stat,READY_STAT,BAD_STAT)) {
                drive->mult_count = drive->mult_req;
        } else {
                drive->mult_req = drive->mult_count = 0;
                drive->special.b.recalibrate = 1;
                (void) ide_dump_status(drive, "set_multmode", stat);
        }
        IDE_DO_REQUEST;
}

/*
 * set_geometry_intr() is invoked on completion of a WIN_SPECIFY cmd.
 */
static void set_geometry_intr (ide_drive_t *drive)
{
        byte stat = GET_STAT();

        sti();
        if (!OK_STAT(stat,READY_STAT,BAD_STAT))
                if (ide_error(drive, "set_geometry_intr", stat))
                        return;
        IDE_DO_REQUEST;
}

/*
 * recal_intr() is invoked on completion of a WIN_RESTORE (recalibrate) cmd.
 */
static void recal_intr (ide_drive_t *drive)
{
        byte stat = GET_STAT();

        sti();
        if (!OK_STAT(stat,READY_STAT,BAD_STAT))
                if (ide_error(drive, "recal_intr", stat))
                        return;
        IDE_DO_REQUEST;
}

/*
 * drive_cmd_intr() is invoked on completion of a special DRIVE_CMD.
 */
static void drive_cmd_intr (ide_drive_t *drive)
{
        byte stat = GET_STAT();

        sti();
        if (OK_STAT(stat,READY_STAT,BAD_STAT))
                end_drive_cmd (drive, stat, GET_ERR());
        else if (ide_error(drive, "drive_cmd", stat)) /* calls end_drive_cmd */
                return;
        IDE_DO_REQUEST;
}

/*
 * do_special() is used to issue WIN_SPECIFY, WIN_RESTORE, and WIN_SETMULT
 * commands to a drive.  It used to do much more, but has been scaled back
 * in recent updates, and could be completely eliminated with a bit more effort.
 */
static inline void do_special (ide_drive_t *drive)
{
        special_t *s = &drive->special;
#ifdef DEBUG
        printk("%s: do_special: 0x%02x\n", drive->name, s->all);
#endif
        if (s->b.set_geometry) {
                s->b.set_geometry = 0;
                if (drive->media == disk) {
                        OUT_BYTE(drive->sect,IDE_SECTOR_REG);
                        OUT_BYTE(drive->cyl,IDE_LCYL_REG);
                        OUT_BYTE(drive->cyl>>8,IDE_HCYL_REG);
                        OUT_BYTE(((drive->head-1)|drive->select.all)&0xBF,IDE_SELECT_REG);
                        ide_cmd(drive, WIN_SPECIFY, drive->sect, &set_geometry_intr);
                }
        } else if (s->b.recalibrate) {
                s->b.recalibrate = 0;
                if (drive->media == disk) {
                        ide_cmd(drive, WIN_RESTORE, drive->sect, &recal_intr);
                }
        } else if (s->b.set_multmode) {
                s->b.set_multmode = 0;
                if (drive->media == disk) {
                        if (drive->id && drive->mult_req > drive->id->max_multsect)
                                drive->mult_req = drive->id->max_multsect;
                        ide_cmd(drive, WIN_SETMULT, drive->mult_req, &set_multmode_intr);
                } else
                        drive->mult_req = 0;
        } else if (s->all) {
                s->all = 0;
                printk("%s: bad special flag: 0x%02x\n", drive->name, s->all);
        }
}

/*
 * This routine busy-waits for the drive status to be not "busy".
 * It then checks the status for all of the "good" bits and none
 * of the "bad" bits, and if all is okay it returns 0.  All other
 * cases return 1 after invoking ide_error()
 *
 * This routine should get fixed to not hog the cpu during extra long waits..
 * That could be done by busy-waiting for the first jiffy or two, and then
 * setting a timer to wake up at half second intervals thereafter,
 * until WAIT_WORSTCASE is achieved, before timing out.
 */
int ide_wait_stat (ide_drive_t *drive, byte good, byte bad, unsigned long timeout)
{
        byte stat;
        unsigned long flags;
test:
        udelay(1);      /* spec allows drive 400ns to change "BUSY" */
        if (OK_STAT((stat = GET_STAT()), good, bad))
                return 0;       /* fast exit for most frequent case */
        if (!(stat & BUSY_STAT)) {
                (void) ide_error(drive, "status error", stat);
                return 1;
        }

        save_flags(flags);
        sti();
        timeout += jiffies;
        do {
                if (!((stat = GET_STAT()) & BUSY_STAT)) {
                        restore_flags(flags);
                        goto test;
                }
        } while (jiffies <= timeout);

        restore_flags(flags);
        (void) ide_error(drive, "status timeout", GET_STAT());
        return 1;
}

/*
 * do_rw_disk() issues WIN_{MULT}READ and WIN_{MULT}WRITE commands to a disk,
 * using LBA if supported, or CHS otherwise, to address sectors.  It also takes
 * care of issuing special DRIVE_CMDs.
 */
static inline void do_rw_disk (ide_drive_t *drive, struct request *rq, unsigned long block)
{
        unsigned short io_base = HWIF(drive)->io_base;

        OUT_BYTE(drive->ctl,IDE_CONTROL_REG);
        OUT_BYTE(rq->nr_sectors,io_base+IDE_NSECTOR_OFFSET);
        if (drive->select.b.lba) {
#ifdef DEBUG
                printk("%s: %sing: LBAsect=%ld, sectors=%ld, buffer=0x%08lx\n",
                        drive->name, (rq->cmd==READ)?"read":"writ", 
                        block, rq->nr_sectors, (unsigned long) rq->buffer);
#endif
                OUT_BYTE(block,io_base+IDE_SECTOR_OFFSET);
                OUT_BYTE(block>>=8,io_base+IDE_LCYL_OFFSET);
                OUT_BYTE(block>>=8,io_base+IDE_HCYL_OFFSET);
                OUT_BYTE(((block>>8)&0x0f)|drive->select.all,io_base+IDE_SELECT_OFFSET);
        } else {
                unsigned int sect,head,cyl,track;
                track = block / drive->sect;
                sect  = block % drive->sect + 1;
                OUT_BYTE(sect,io_base+IDE_SECTOR_OFFSET);
                head  = track % drive->head;
                cyl   = track / drive->head;
                OUT_BYTE(cyl,io_base+IDE_LCYL_OFFSET);
                OUT_BYTE(cyl>>8,io_base+IDE_HCYL_OFFSET);
                OUT_BYTE(head|drive->select.all,io_base+IDE_SELECT_OFFSET);
#ifdef DEBUG
                printk("%s: %sing: CHS=%d/%d/%d, sectors=%ld, buffer=0x%08lx\n",
                        drive->name, (rq->cmd==READ)?"read":"writ", cyl,
                        head, sect, rq->nr_sectors, (unsigned long) rq->buffer);
#endif
        }
        if (rq->cmd == READ) {
#ifdef CONFIG_BLK_DEV_TRITON
                if (drive->using_dma && !(HWIF(drive)->dmaproc(ide_dma_read, drive)))
                        return;
#endif /* CONFIG_BLK_DEV_TRITON */
                ide_set_handler(drive, &read_intr);
                OUT_BYTE(drive->mult_count ? WIN_MULTREAD : WIN_READ, io_base+IDE_COMMAND_OFFSET);
                return;
        }
        if (rq->cmd == WRITE) {
#ifdef CONFIG_BLK_DEV_TRITON
                if (drive->using_dma && !(HWIF(drive)->dmaproc(ide_dma_write, drive)))
                        return;
#endif /* CONFIG_BLK_DEV_TRITON */
                OUT_BYTE(drive->mult_count ? WIN_MULTWRITE : WIN_WRITE, io_base+IDE_COMMAND_OFFSET);
                if (ide_wait_stat(drive, DATA_READY, drive->bad_wstat, WAIT_DRQ)) {
                        printk("%s: no DRQ after issuing %s\n", drive->name,
                                drive->mult_count ? "MULTWRITE" : "WRITE");
                        return;
                }
                if (!drive->unmask)
                        cli();
                if (drive->mult_count) {
                        HWGROUP(drive)->wrq = *rq; /* scratchpad */
                        ide_set_handler (drive, &multwrite_intr);
                        multwrite(drive);
                } else {
                        ide_set_handler (drive, &write_intr);
                        ide_output_data(drive, rq->buffer, SECTOR_WORDS);
                }
                return;
        }
        if (rq->cmd == IDE_DRIVE_CMD) {
                byte *args = rq->buffer;
                if (args) {
                        printk("%s: DRIVE_CMD cmd=0x%02x sc=0x%02x fr=0x%02x\n",
                         drive->name, args[0], args[1], args[2]);
                        OUT_BYTE(args[2],io_base+IDE_FEATURE_OFFSET);
                        ide_cmd(drive, args[0], args[1], &drive_cmd_intr);
                        return;
                } else {
                        /*
                         * NULL is actually a valid way of waiting for
                         * all current requests to be flushed from the queue.
                         */
#ifdef DEBUG
                        printk("%s: DRIVE_CMD (null)\n", drive->name);
#endif
                        end_drive_cmd(drive, GET_STAT(), GET_ERR());
                        return;
                }
        }
        printk("%s: bad command: %d\n", drive->name, rq->cmd);
        ide_end_request(0, HWGROUP(drive));
}

/*
 * do_request() initiates handling of a new I/O request
 */
static inline void do_request (ide_hwif_t *hwif, struct request *rq)
{
        unsigned int minor, unit;
        unsigned long block, blockend;
        ide_drive_t *drive;

        sti();
#ifdef DEBUG
        printk("%s: ide_do_request: current=0x%08lx\n", hwif->name, (unsigned long) rq);
#endif
        minor = MINOR(rq->rq_dev);
        unit = minor >> PARTN_BITS;
        if (MAJOR(rq->rq_dev) != hwif->major || unit >= MAX_DRIVES) {
                printk("%s: bad device number: %s\n",
                       hwif->name, kdevname(rq->rq_dev));
                goto kill_rq;
        }
        drive = &hwif->drives[unit];
#ifdef DEBUG
        if (rq->bh && !rq->bh->b_lock) {
                printk("%s: block not locked\n", drive->name);
                goto kill_rq;
        }
#endif
        block    = rq->sector;
        blockend = block + rq->nr_sectors;
        if ((blockend < block) || (blockend > drive->part[minor&PARTN_MASK].nr_sects)) {
                printk("%s%c: bad access: block=%ld, count=%ld\n", drive->name,
                 (minor&PARTN_MASK)?'0'+(minor&PARTN_MASK):' ', block, rq->nr_sectors);
                goto kill_rq;
        }
        block += drive->part[minor&PARTN_MASK].start_sect + drive->sect0;
#if FAKE_FDISK_FOR_EZDRIVE
        if (block == 0 && drive->ezdrive) {
                block = 1;
                printk("%s: [EZD] accessing sector 1 instead of sector 0\n", drive->name);
        }
#endif /* FAKE_FDISK_FOR_EZDRIVE */
        ((ide_hwgroup_t *)hwif->hwgroup)->drive = drive;
#if (DISK_RECOVERY_TIME > 0)
        while ((read_timer() - hwif->last_time) < DISK_RECOVERY_TIME);
#endif
#if SUPPORT_HT6560B
        if (hwif->select)
                ide_hwif_select (hwif);
#endif
        OUT_BYTE(drive->select.all,IDE_SELECT_REG);
        if (ide_wait_stat(drive, drive->ready_stat, BUSY_STAT|DRQ_STAT, WAIT_READY)) {
                printk("%s: drive not ready for command\n", drive->name);
                return;

        }
        if (!drive->special.all) {
#ifdef CONFIG_BLK_DEV_IDECD
                switch (drive->media) {
                        case disk:
                                do_rw_disk (drive, rq, block);
                                return;
                        case cdrom:
                                ide_do_rw_cdrom (drive, block);
                                return;
                        default:
                                printk("%s: media type %d not supported\n",
                                        drive->name, drive->media);
                                goto kill_rq;
                }
#else
                do_rw_disk (drive, rq, block); /* simpler and faster */
                return;
#endif;
        }
        do_special(drive);
        return;
kill_rq:
        ide_end_request(0, hwif->hwgroup);
}

/*
 * The driver enables interrupts as much as possible.  In order to do this,
 * (a) the device-interrupt is always masked before entry, and
 * (b) the timeout-interrupt is always disabled before entry.
 *
 * If we enter here from, say irq14, and then start a new request for irq15,
 * (possible with "serialize" option) then we cannot ensure that we exit
 * before the irq15 hits us. So, we must be careful not to let this bother us.
 *
 * Interrupts are still masked (by default) whenever we are exchanging
 * data/cmds with a drive, because some drives seem to have very poor
 * tolerance for latency during I/O.  For devices which don't suffer from
 * this problem (most don't), the unmask flag can be set using the "hdparm"
 * utility, to permit other interrupts during data/cmd transfers.
 */
void ide_do_request (ide_hwgroup_t *hwgroup)
{
        cli();  /* paranoia */
        if (hwgroup->handler != NULL) {
                printk("%s: EEeekk!! handler not NULL in ide_do_request()\n", hwgroup->hwif->name);
                return;
        }
        do {
                ide_hwif_t *hwif = hwgroup->hwif;
                struct request *rq;
                if ((rq = hwgroup->rq) == NULL) {
                        hwgroup->drive = NULL;  /* paranoia */
                        do {
                                rq = blk_dev[hwif->major].current_request;
                                if (rq != NULL && rq->rq_status != RQ_INACTIVE)
                                        goto got_rq;
                        } while ((hwif = hwif->next) != hwgroup->hwif);
                        return;         /* no work left for this hwgroup */
                got_rq:
                        blk_dev[hwif->major].current_request = rq->next;
                }
                do_request(hwgroup->hwif = hwif, hwgroup->rq = rq);
                cli();
        } while (hwgroup->handler == NULL);
}

/*
 * do_hwgroup_request() invokes ide_do_request() after first masking
 * all possible interrupts for the current hwgroup.  This prevents race
 * conditions in the event that an unexpected interrupt occurs while
 * we are in the driver.
 *
 * Note that when an interrupt is used to reenter the driver, the first level
 * handler will already have masked the irq that triggered, but any other ones
 * for the hwgroup will still be unmasked.  The driver tries to be careful
 * about such things.
 */
static void do_hwgroup_request (ide_hwgroup_t *hwgroup)
{
        if (hwgroup->handler == NULL) {
                ide_hwif_t *hgif = hwgroup->hwif;
                ide_hwif_t *hwif = hgif;
                do {
                        disable_irq(hwif->irq);
                } while ((hwif = hwif->next) != hgif);
                ide_do_request (hwgroup);
                do {
                        enable_irq(hwif->irq);
                } while ((hwif = hwif->next) != hgif);
        }
}

static void do_ide0_request (void)      /* invoked with cli() */
{
        do_hwgroup_request (ide_hwifs[0].hwgroup);
}

static void do_ide1_request (void)      /* invoked with cli() */
{
        do_hwgroup_request (ide_hwifs[1].hwgroup);
}

static void do_ide2_request (void)      /* invoked with cli() */
{
        do_hwgroup_request (ide_hwifs[2].hwgroup);
}

static void do_ide3_request (void)      /* invoked with cli() */
{
        do_hwgroup_request (ide_hwifs[3].hwgroup);
}

static void timer_expiry (unsigned long data)
{
        ide_hwgroup_t *hwgroup = (ide_hwgroup_t *) data;
        ide_drive_t   *drive   = hwgroup->drive;
        unsigned long flags;

        save_flags(flags);
        cli();

        if (hwgroup->reset_timeout != 0) { /* ide reset in progress? */
                if (!reset_handler(hwgroup))
                        do_hwgroup_request (hwgroup);
        } else if (hwgroup->handler == NULL) {   /* not waiting for anything? */
                sti(); /* drive must have responded just as the timer expired */
                printk("%s: marginal timeout\n", drive->name);
        } else {                                 /* drive not responding */
                hwgroup->handler = NULL;
                if (hwgroup->hwif->dmaproc) 
                        (void) hwgroup->hwif->dmaproc (ide_dma_abort, drive);
                if (!ide_error(drive, "irq timeout", GET_STAT()))
                        do_hwgroup_request (hwgroup);
        }
        restore_flags(flags);
}

/*
 * There's nothing really useful we can do with an unexpected interrupt,
 * other than reading the status register (to clear it), and logging it.
 * There should be no way that an irq can happen before we're ready for it,
 * so we needn't worry much about losing an "important" interrupt here.
 *
 * On laptops (and "green" PCs), an unexpected interrupt occurs whenever the
 * drive enters "idle", "standby", or "sleep" mode, so if the status looks
 * "good", we just ignore the interrupt completely.
 *
 * This routine assumes cli() is in effect when called.
 *
 * If an unexpected interrupt happens on irq15 while we are handling irq14
 * and if the two interfaces are "serialized" (CMD640B), then it looks like
 * we could screw up by interfering with a new request being set up for irq15.
 *
 * In reality, this is a non-issue.  The new command is not sent unless the
 * drive is ready to accept one, in which case we know the drive is not
 * trying to interrupt us.  And ide_set_handler() is always invoked before
 * completing the issuance of any new drive command, so we will not be 
 * accidently invoked as a result of any valid command completion interrupt.
 *
 */
static void unexpected_intr (int irq, ide_hwgroup_t *hwgroup)
{
        byte stat;
        unsigned int unit;
        ide_hwif_t *hwif = hwgroup->hwif;

        /*
         * check for ide reset in progress
         */
        if (hwgroup->reset_timeout != 0) {
                if (!reset_handler(hwgroup))
                        do_hwgroup_request (hwgroup);
                return;
        }

        /*
         * handle the unexpected interrupt
         */
        do {
                if (hwif->irq == irq) {
#if SUPPORT_HT6560B
                        if (hwif->select)
                                ide_hwif_select (hwif);
#endif
                        for (unit = 0; unit < MAX_DRIVES; ++unit) {
                                ide_drive_t *drive = &hwif->drives[unit];
                                if (!drive->present)
                                        continue;
                                if (!OK_STAT(stat=GET_STAT(), drive->ready_stat, BAD_STAT))
                                        (void) ide_dump_status(drive, "unexpected_intr", stat);
                                if ((stat & DRQ_STAT))
                                        try_to_flush_leftover_data(drive);
                        }
                }
        } while ((hwif = hwif->next) != hwgroup->hwif);
}

/*
 * entry point for all interrupts, caller does cli() for us
 */
static void ide_intr (int irq, struct pt_regs *regs)
{
        ide_hwgroup_t  *hwgroup = irq_to_hwgroup[irq];
        ide_handler_t  *handler;

        if (irq == hwgroup->hwif->irq && (handler = hwgroup->handler) != NULL) {
                ide_drive_t *drive = hwgroup->drive;
                hwgroup->handler = NULL;
                del_timer(&(hwgroup->timer));
                if (drive->unmask)
                        sti();
                handler(drive);
        } else {
                unexpected_intr(irq, hwgroup);
        }
        cli();
}

/*
 * get_info_ptr() returns the (ide_drive_t *) for a given device number.
 * It returns NULL if the given device number does not match any present drives.
 */
static ide_drive_t *get_info_ptr (kdev_t i_rdev)
{
        int             major = MAJOR(i_rdev);
        unsigned int    h;

        for (h = 0; h < MAX_HWIFS; ++h) {
                ide_hwif_t  *hwif = &ide_hwifs[h];
                if (hwif->present && major == hwif->major) {
                        unsigned unit = DEVICE_NR(i_rdev);
                        if (unit < MAX_DRIVES) {
                                ide_drive_t *drive = &hwif->drives[unit];
                                if (drive->present)
                                        return drive;
                        } else if (major == IDE0_MAJOR && unit < 4) {
                                printk("ide: probable bad entry for /dev/hd%c%d\n",
                                 'a' + unit, MINOR(i_rdev) & PARTN_MASK);
                                printk("ide: to fix it, run:  /usr/src/linux/drivers/block/MAKEDEV.ide\n");
                        }
                        break;
                }
        }
        return NULL;
}

/*
 * This function issues a specific IDE drive command onto the
 * tail of the request queue, and waits for it to be completed.
 * If arg is NULL, it goes through all the motions,
 * but without actually sending a command to the drive.
 */
int ide_do_drive_cmd(kdev_t rdev, char *args)
{
        unsigned long flags;
        unsigned int major = MAJOR(rdev);
        struct request rq, *cur_rq;
        struct blk_dev_struct *bdev;
        struct semaphore sem = MUTEX_LOCKED;

        /* build up a special request, and add it to the queue */
        rq.buffer = args;
        rq.cmd = IDE_DRIVE_CMD;
        rq.errors = 0;
        rq.sector = 0;
        rq.nr_sectors = 0;
        rq.current_nr_sectors = 0;
        rq.sem = &sem;
        rq.bh = NULL;
        rq.bhtail = NULL;
        rq.next = NULL;
        rq.rq_status = RQ_ACTIVE;
        rq.rq_dev = rdev;
        bdev = &blk_dev[major];

        save_flags(flags);
        cli();
        cur_rq = bdev->current_request;
        if (cur_rq == NULL) {                   /* empty request list? */
                bdev->current_request = &rq;    /* service ours immediately */
                bdev->request_fn();
        } else {
                while (cur_rq->next != NULL)    /* find end of request list */
                        cur_rq = cur_rq->next;
                cur_rq->next = &rq;             /* add rq to the end */
        }

        down(&sem);                             /* wait for it to be serviced */
        restore_flags(flags);
        return rq.errors ? -EIO : 0;            /* return -EIO if errors */
}

static int ide_open(struct inode * inode, struct file * filp)
{
        ide_drive_t *drive;
        unsigned long flags;

        if ((drive = get_info_ptr(inode->i_rdev)) == NULL)
                return -ENODEV;
        save_flags(flags);
        cli();
        while (drive->busy)
                sleep_on(&drive->wqueue);
        drive->usage++;
        restore_flags(flags);
#ifdef CONFIG_BLK_DEV_IDECD
        if (drive->media == cdrom)
                return ide_cdrom_open (inode, filp, drive);
#endif  /* CONFIG_BLK_DEV_IDECD */
        if (drive->removeable) {
                byte door_lock[] = {WIN_DOORLOCK,0,0,0};
                check_disk_change(inode->i_rdev);
                ide_do_drive_cmd(inode->i_rdev, door_lock);
        }
        return 0;
}

/*
 * Releasing a block device means we sync() it, so that it can safely
 * be forgotten about...
 */
static void ide_release(struct inode * inode, struct file * file)
{
        ide_drive_t *drive;

        if ((drive = get_info_ptr(inode->i_rdev)) != NULL) {
                sync_dev(inode->i_rdev);
                drive->usage--;
#ifdef CONFIG_BLK_DEV_IDECD
                if (drive->media == cdrom)
                        ide_cdrom_release (inode, file, drive);
                else
#endif  /* CONFIG_BLK_DEV_IDECD */
                if (drive->removeable) {
                        byte door_unlock[] = {WIN_DOORUNLOCK,0,0,0};
                        invalidate_buffers(inode->i_rdev);
                        ide_do_drive_cmd(inode->i_rdev, door_unlock);
                }
        }
}

/*
 * This routine is called to flush all partitions and partition tables
 * for a changed disk, and then re-read the new partition table.
 * If we are revalidating a disk because of a media change, then we
 * enter with usage == 0.  If we are using an ioctl, we automatically have
 * usage == 1 (we need an open channel to use an ioctl :-), so this
 * is our limit.
 */
static int revalidate_disk(kdev_t i_rdev)
{
        ide_drive_t *drive;
        unsigned int p, major, minor;
        long flags;

        if ((drive = get_info_ptr(i_rdev)) == NULL)
                return -ENODEV;

        major = MAJOR(i_rdev);
        minor = drive->select.b.unit << PARTN_BITS;
        save_flags(flags);
        cli();
        if (drive->busy || (drive->usage > 1)) {
                restore_flags(flags);
                return -EBUSY;
        };
        drive->busy = 1;
        restore_flags(flags);

        for (p = 0; p < (1<<PARTN_BITS); ++p) {
                if (drive->part[p].nr_sects > 0) {
                        kdev_t devp = MKDEV(major, minor+p);
                        sync_dev           (devp);
                        invalidate_inodes  (devp);
                        invalidate_buffers (devp);
                }
                drive->part[p].start_sect = 0;
                drive->part[p].nr_sects   = 0;
        };

        drive->part[0].nr_sects = current_capacity(drive);
        if (drive->media == disk)
                resetup_one_dev(HWIF(drive)->gd, drive->select.b.unit);

        drive->busy = 0;
        wake_up(&drive->wqueue);
        return 0;
}

static int write_fs_long (unsigned long useraddr, long value)
{
        int err;

        if (NULL == (long *)useraddr)
                return -EINVAL;
        if ((err = verify_area(VERIFY_WRITE, (long *)useraddr, sizeof(long))))
                return err;
        put_user((unsigned)value, (long *) useraddr);
        return 0;
}

static int ide_ioctl (struct inode *inode, struct file *file,
                        unsigned int cmd, unsigned long arg)
{
        struct hd_geometry *loc = (struct hd_geometry *) arg;
        int err;
        ide_drive_t *drive;
        unsigned long flags;

        if (!inode || !(inode->i_rdev))
                return -EINVAL;
        if ((drive = get_info_ptr(inode->i_rdev)) == NULL)
                return -ENODEV;
        switch (cmd) {
                case HDIO_GETGEO:
                        if (!loc || drive->media != disk) return -EINVAL;
                        err = verify_area(VERIFY_WRITE, loc, sizeof(*loc));
                        if (err) return err;
                        put_user(drive->bios_head, (byte *) &loc->heads);
                        put_user(drive->bios_sect, (byte *) &loc->sectors);
                        put_user(drive->bios_cyl, (unsigned short *) &loc->cylinders);
                        put_user((unsigned)drive->part[MINOR(inode->i_rdev)&PARTN_MASK].start_sect,
                                (unsigned long *) &loc->start);
                        return 0;

                case BLKFLSBUF:
                        if(!suser()) return -EACCES;
                        fsync_dev(inode->i_rdev);
                        invalidate_buffers(inode->i_rdev);
                        return 0;

                case BLKRASET:
                        if(!suser()) return -EACCES;
                        if(arg > 0xff) return -EINVAL;
                        read_ahead[MAJOR(inode->i_rdev)] = arg;
                        return 0;

                case BLKRAGET:
                        return write_fs_long(arg, read_ahead[MAJOR(inode->i_rdev)]);

                case BLKGETSIZE:   /* Return device size */
                        return write_fs_long(arg, drive->part[MINOR(inode->i_rdev)&PARTN_MASK].nr_sects);
                case BLKRRPART: /* Re-read partition tables */
                        return revalidate_disk(inode->i_rdev);

                case HDIO_GET_KEEPSETTINGS:
                        return write_fs_long(arg, drive->keep_settings);

                case HDIO_GET_UNMASKINTR:
                        return write_fs_long(arg, drive->unmask);

                case HDIO_GET_DMA:
                        return write_fs_long(arg, drive->using_dma);

                case HDIO_GET_CHIPSET:
                        return write_fs_long(arg, drive->chipset);

                case HDIO_GET_MULTCOUNT:
                        return write_fs_long(arg, drive->mult_count);

                case HDIO_GET_IDENTITY:
                        if (!arg || (MINOR(inode->i_rdev) & PARTN_MASK))
                                return -EINVAL;
                        if (drive->id == NULL)
                                return -ENOMSG;
                        err = verify_area(VERIFY_WRITE, (char *)arg, sizeof(*drive->id));
                        if (!err)
                                memcpy_tofs((char *)arg, (char *)drive->id, sizeof(*drive->id));
                        return err;

                        case HDIO_GET_NOWERR:
                        return write_fs_long(arg, drive->bad_wstat == BAD_R_STAT);

                case HDIO_SET_DMA:
                        if (drive->media != disk)
                                return -EPERM;
                        if (!drive->id || !(drive->id->capability & 1) || !HWIF(drive)->dmaproc)
                                return -EPERM;
                case HDIO_SET_KEEPSETTINGS:
                case HDIO_SET_UNMASKINTR:
                case HDIO_SET_NOWERR:
                        if (arg > 1)
                                return -EINVAL;
                case HDIO_SET_CHIPSET:
                        if (!suser())
                                return -EACCES;
                        if ((MINOR(inode->i_rdev) & PARTN_MASK))
                                return -EINVAL;
                        save_flags(flags);
                        cli();
                        switch (cmd) {
                                case HDIO_SET_DMA:
                                        drive->using_dma = arg;
                                        break;
                                case HDIO_SET_KEEPSETTINGS:
                                        drive->keep_settings = arg;
                                        break;
                                case HDIO_SET_UNMASKINTR:
                                        if (arg && disallow_unmask) {
                                                restore_flags(flags);
                                                return -EPERM;
                                        }
                                        drive->unmask = arg;
                                        break;
                                case HDIO_SET_NOWERR:
                                        drive->bad_wstat = arg ? BAD_R_STAT : BAD_W_STAT;
                                        break;
                                case HDIO_SET_CHIPSET:
                                        drive->chipset   = arg;
                                        drive->vlb_32bit = (arg & 1);
                                        drive->vlb_sync  = (arg & 2) >> 1;
#ifndef VLB_SYNC
                                        if (drive->vlb_sync)
                                                printk("%s: VLB_SYNC not supported by this kernel\n", drive->name);
#endif
                                        break;
                        }
                        restore_flags(flags);
                        return 0;

                case HDIO_SET_MULTCOUNT:
                        if (!suser())
                                return -EACCES;
                        if (MINOR(inode->i_rdev) & PARTN_MASK)
                                return -EINVAL;
                        if ((drive->id != NULL) && (arg > drive->id->max_multsect))
                                return -EINVAL;
                        save_flags(flags);
                        cli();
                        if (drive->special.b.set_multmode) {
                                restore_flags(flags);
                                return -EBUSY;
                        }
                        drive->mult_req = arg;
                        drive->special.b.set_multmode = 1;
                        restore_flags(flags);
                        ide_do_drive_cmd (inode->i_rdev, NULL);
                        return (drive->mult_count == arg) ? 0 : -EIO;

                case HDIO_DRIVE_CMD:
                {
                        unsigned long args;

                        if (NULL == (long *) arg)
                                err = ide_do_drive_cmd(inode->i_rdev,NULL);
                        else {
                                if (!(err = verify_area(VERIFY_READ,(long *)arg,sizeof(long))))
                                {
                                        args = get_user((long *)arg);
                                        if (!(err = verify_area(VERIFY_WRITE,(long *)arg,sizeof(long)))) {
                                                err = ide_do_drive_cmd(inode->i_rdev,(char *)&args);
                                                put_user(args,(long *)arg);
                                        }
                                }
                        }
                        return err;
                }

                RO_IOCTLS(inode->i_rdev, arg);

                default:
#ifdef CONFIG_BLK_DEV_IDECD
                        if (drive->media == cdrom)
                                return ide_cdrom_ioctl(drive, inode, file, cmd, arg);
#endif /* CONFIG_BLK_DEV_IDECD */
                        return -EPERM;
        }
}

static int ide_check_media_change (kdev_t i_rdev)
{
        ide_drive_t *drive;

        if ((drive = get_info_ptr(i_rdev)) == NULL)
                return -ENODEV;
#ifdef CONFIG_BLK_DEV_IDECD
        if (drive->media == cdrom)
                return ide_cdrom_check_media_change (drive);
#endif  /* CONFIG_BLK_DEV_IDECD */
        if (drive->removeable) /* for disks */
                return 1;       /* always assume it was changed */
        return 0;
}

static void fixstring (byte *s, const int bytecount, const int byteswap)
{
        byte *p = s, *end = &s[bytecount & ~1]; /* bytecount must be even */

        if (byteswap) {
                /* convert from big-endian to host byte order */
                for (p = end ; p != s;) {
                        unsigned short *pp = (unsigned short *) (p -= 2);
                        *pp = ntohs(*pp);
                }
        }

        /* strip leading blanks */
        while (s != end && *s == ' ')
                ++s;

        /* compress internal blanks and strip trailing blanks */
        while (s != end && *s) {
                if (*s++ != ' ' || (s != end && *s && *s != ' '))
                        *p++ = *(s-1);
        }

        /* wipe out trailing garbage */
        while (p != end)
                *p++ = '\0';
}

static inline void do_identify (ide_drive_t *drive, byte cmd)
{
        int bswap;
        struct hd_driveid *id;
        unsigned long capacity, check;

        id = drive->id = kmalloc (SECTOR_WORDS*4, GFP_KERNEL);
        ide_input_data(drive, id, SECTOR_WORDS);        /* read 512 bytes of id info */
        sti();

        /*
         * EATA SCSI controllers do a hardware ATA emulation:  ignore them
         */
        if ((id->model[0] == 'P' && id->model[1] == 'M')
         || (id->model[0] == 'S' && id->model[1] == 'K')) {
                printk("%s: EATA SCSI HBA %.10s\n", drive->name, id->model);
                drive->present = 0;
                return;
        }

        /*
         *  WIN_IDENTIFY returns little-endian info,
         *  WIN_PIDENTIFY *usually* returns little-endian info.
         */
        bswap = 1;
        if (cmd == WIN_PIDENTIFY) {
                if ((id->model[0] == 'N' && id->model[1] == 'E') /* NEC */
                 || (id->model[0] == 'F' && id->model[1] == 'X') /* Mitsumi */
                 || (id->model[0] == 'P' && id->model[1] == 'i'))/* Pioneer */
                        bswap = 0;      /* Vertos drives may still be weird */
        }
        fixstring (id->model,     sizeof(id->model),     bswap);
        fixstring (id->fw_rev,    sizeof(id->fw_rev),    bswap);
        fixstring (id->serial_no, sizeof(id->serial_no), bswap);

        /*
         * Check for an ATAPI device
         */
        if (cmd == WIN_PIDENTIFY) {
#ifdef CONFIG_BLK_DEV_IDECD
                byte type = (id->config >> 8) & 0x0f;
#endif  /* CONFIG_BLK_DEV_IDECD */
                printk("%s: %s, ATAPI, ", drive->name, id->model);
                drive->media = cdrom;
#ifdef CONFIG_BLK_DEV_IDECD
                if (type == 0 || type == 5)
                        printk("CDROM drive\n");
                else
                        printk("UNKNOWN device\n");
                drive->present = 1;
                drive->removeable = 1;
#else
                printk("not supported by this kernel\n");
#endif  /* CONFIG_BLK_DEV_IDECD */
                return;
        }

        /* check for removeable disks (eg. SYQUEST), ignore 'WD' drives */
        if (id->config & (1<<7)) {      /* removeable disk ? */
                if (id->model[0] != 'W' || id->model[1] != 'D')
                        drive->removeable = 1;
        }

        drive->media = disk;
        /* Extract geometry if we did not already have one for the drive */
        if (!drive->present) {
                drive->present = 1;
                drive->cyl     = drive->bios_cyl  = id->cyls;
                drive->head    = drive->bios_head = id->heads;
                drive->sect    = drive->bios_sect = id->sectors; 
        }
        /* Handle logical geometry translation by the drive */
        if ((id->field_valid & 1) && id->cur_cyls && id->cur_heads
         && (id->cur_heads <= 16) && id->cur_sectors)
        {
                /*
                 * Extract the physical drive geometry for our use.
                 * Note that we purposely do *not* update the bios info.
                 * This way, programs that use it (like fdisk) will 
                 * still have the same logical view as the BIOS does,
                 * which keeps the partition table from being screwed.
                 *
                 * An exception to this is the cylinder count,
                 * which we reexamine later on to correct for 1024 limitations.
                 */
                drive->cyl  = id->cur_cyls;
                drive->head = id->cur_heads;
                drive->sect = id->cur_sectors;

                /* check for word-swapped "capacity" field in id information */
                capacity = drive->cyl * drive->head * drive->sect;
                check = (id->cur_capacity0 << 16) | id->cur_capacity1;
                if (check == capacity) {        /* was it swapped? */
                        /* yes, bring it into little-endian order: */
                        id->cur_capacity0 = (capacity >>  0) & 0xffff;
                        id->cur_capacity1 = (capacity >> 16) & 0xffff;
                }
        }
        /* Use physical geometry if what we have still makes no sense */
        if ((!drive->head || drive->head > 16) && id->heads && id->heads <= 16) {
                drive->cyl  = id->cyls;
                drive->head = id->heads;
                drive->sect = id->sectors; 
        }
        /* Correct the number of cyls if the bios value is too small */
        if (drive->sect == drive->bios_sect && drive->head == drive->bios_head) {
                if (drive->cyl > drive->bios_cyl)
                        drive->bios_cyl = drive->cyl;
        }

        (void) current_capacity (drive); /* initialize LBA selection */

        printk ("%s: %.40s, %ldMB w/%dKB Cache, %sCHS=%d/%d/%d",
         drive->name, id->model, current_capacity(drive)/2048L, id->buf_size/2,
         drive->select.b.lba ? "LBA, " : "",
         drive->bios_cyl, drive->bios_head, drive->bios_sect);

        drive->mult_count = 0;
        if (id->max_multsect) {
                drive->mult_req = INITIAL_MULT_COUNT;
                if (drive->mult_req > id->max_multsect)
                        drive->mult_req = id->max_multsect;
                if (drive->mult_req || ((id->multsect_valid & 1) && id->multsect))
                        drive->special.b.set_multmode = 1;
        }
        if (HWIF(drive)->dmaproc != NULL) {     /* hwif supports DMA? */
                if (!(HWIF(drive)->dmaproc(ide_dma_check, drive)))
                        printk(", DMA");
        }
        printk("\n");
}

/*
 * Delay for *at least* 10ms.  As we don't know how much time is left
 * until the next tick occurs, we wait an extra tick to be safe.
 */
static void delay_10ms (void)
{
        unsigned long timer = jiffies + (HZ + 99)/100 + 1;
        while (timer > jiffies);
}

/*
 * try_to_identify() sends an ATA(PI) IDENTIFY request to a drive
 * and waits for a response.  It also monitors irqs while this is
 * happening, in hope of automatically determining which one is
 * being used by the interface.
 *
 * Returns:     0  device was identified
 *              1  device timed-out (no response to identify request)
 *              2  device aborted the command (refused to identify itself)
 */
static int try_to_identify (ide_drive_t *drive, byte cmd)
{
        int hd_status, rc;
        unsigned long timeout;
        int irqs = 0;

        if (!HWIF(drive)->irq) {                /* already got an IRQ? */
                probe_irq_off(probe_irq_on());  /* clear dangling irqs */
                irqs = probe_irq_on();          /* start monitoring irqs */
                OUT_BYTE(drive->ctl,IDE_CONTROL_REG);   /* enable device irq */
        }

        delay_10ms();                           /* take a deep breath */
        if ((IN_BYTE(IDE_ALTSTATUS_REG) ^ IN_BYTE(IDE_STATUS_REG)) & ~INDEX_STAT) {
                printk("%s: probing with STATUS instead of ALTSTATUS\n", drive->name);
                hd_status = IDE_STATUS_REG;     /* ancient Seagate drives */
        } else
                hd_status = IDE_ALTSTATUS_REG;  /* use non-intrusive polling */

        OUT_BYTE(cmd,IDE_COMMAND_REG);          /* ask drive for ID */
        timeout = ((cmd == WIN_IDENTIFY) ? WAIT_WORSTCASE : WAIT_PIDENTIFY) / 2;
        timeout += jiffies;
        do {
                if (jiffies > timeout) {
                        if (!HWIF(drive)->irq)
                                (void) probe_irq_off(irqs);
                        return 1;       /* drive timed-out */
                }
                delay_10ms();           /* give drive a breather */
        } while (IN_BYTE(hd_status) & BUSY_STAT);

        delay_10ms();           /* wait for IRQ and DRQ_STAT */
        if (OK_STAT(GET_STAT(),DRQ_STAT,BAD_R_STAT)) {
                cli();                  /* some systems need this */
                do_identify(drive, cmd); /* drive returned ID */
                rc = 0;                 /* success */
        } else
                rc = 2;                 /* drive refused ID */
        if (!HWIF(drive)->irq) {
                irqs = probe_irq_off(irqs);     /* get irq number */
                if (irqs > 0)
                        HWIF(drive)->irq = irqs;
                else                            /* Mmmm.. multiple IRQs */
                        printk("%s: IRQ probe failed (%d)\n", drive->name, irqs);
        }
        return rc;
}

/*
 * do_probe() has the difficult job of finding a drive if it exists,
 * without getting hung up if it doesn't exist, without trampling on
 * ethernet cards, and without leaving any IRQs dangling to haunt us later.
 *
 * If a drive is "known" to exist (from CMOS or kernel parameters),
 * but does not respond right away, the probe will "hang in there"
 * for the maximum wait time (about 30 seconds), otherwise it will
 * exit much more quickly.
 *
 * Returns:     0  device was identified
 *              1  device timed-out (no response to identify request)
 *              2  device aborted the command (refused to identify itself)
 *              3  bad status from device (possible for ATAPI drives)
 *              4  probe was not attempted because failure was obvious
 */
static int do_probe (ide_drive_t *drive, byte cmd)
{
        int rc;
#ifdef CONFIG_BLK_DEV_IDECD
        if (drive->present) {   /* avoid waiting for inappropriate probes */
                if ((drive->media == cdrom) && (cmd == WIN_IDENTIFY))
                        return 4;
        }
#endif  /* CONFIG_BLK_DEV_IDECD */
#ifdef DEBUG
        printk("probing for %s: present=%d, type=%s, probetype=%s\n",
                drive->name, drive->present, drive->media ? "cdrom":"disk",
                (cmd == WIN_IDENTIFY) ? "ATA" : "ATAPI");
#endif
#if SUPPORT_HT6560B
        if (HWIF(drive)->select)
                ide_hwif_select (HWIF(drive));
#endif
        OUT_BYTE(drive->select.all,IDE_SELECT_REG);     /* select target drive */
        delay_10ms();                           /* wait for BUSY_STAT */
        if (IN_BYTE(IDE_SELECT_REG) != drive->select.all && !drive->present) {
                OUT_BYTE(0xa0,IDE_SELECT_REG);  /* exit with drive0 selected */
                return 3;    /* no i/f present: avoid killing ethernet cards */
        }

        if (OK_STAT(GET_STAT(),READY_STAT,BUSY_STAT)
         || drive->present || cmd == WIN_PIDENTIFY)
        {
                if ((rc = try_to_identify(drive,cmd)))   /* send cmd and wait */
                        rc = try_to_identify(drive,cmd); /* failed: try again */
                if (rc == 1)
                        printk("%s: no response (status = 0x%02x)\n", drive->name, GET_STAT());
                (void) GET_STAT();              /* ensure drive irq is clear */
        } else {
                rc = 3;                         /* not present or maybe ATAPI */
        }
        if (drive->select.b.unit != 0) {
                OUT_BYTE(0xa0,IDE_SELECT_REG);  /* exit with drive0 selected */
                delay_10ms();
                (void) GET_STAT();              /* ensure drive irq is clear */
        }
        return rc;
}

/*
 * probe_for_drive() tests for existance of a given drive using do_probe().
 *
 * Returns:     0  no device was found
 *              1  device was found (note: drive->present might still be 0)
 */
static inline byte probe_for_drive (ide_drive_t *drive)
{
        if (drive->noprobe)                     /* skip probing? */
                return drive->present;
        if (do_probe(drive, WIN_IDENTIFY) >= 2) { /* if !(success||timed-out) */
#ifdef CONFIG_BLK_DEV_IDECD
                (void) do_probe(drive, WIN_PIDENTIFY); /* look for ATAPI device */
#endif  /* CONFIG_BLK_DEV_IDECD */
        }
        if (!drive->present)
                return 0;                       /* drive not found */
        if (drive->id == NULL) {                /* identification failed? */
                if (drive->media == disk) {
                        printk ("%s: non-IDE drive, CHS=%d/%d/%d\n",
                         drive->name, drive->cyl, drive->head, drive->sect);
                }
#ifdef CONFIG_BLK_DEV_IDECD
                else if (drive->media == cdrom) {
                        printk("%s: ATAPI cdrom (?)\n", drive->name);
                }
#endif  /* CONFIG_BLK_DEV_IDECD */
                else {
                        drive->present = 0;     /* nuke it */
                        return 1;               /* drive was found */
                }
        }
        if (drive->media == disk && !drive->select.b.lba) {
                if (!drive->head || drive->head > 16) {
                        printk("%s: INVALID GEOMETRY: %d PHYSICAL HEADS?\n",
                         drive->name, drive->head);
                        drive->present = 0;
                }
        }
        return 1;       /* drive was found */
}

/*
 *  This routine only knows how to look for drive units 0 and 1
 *  on an interface, so any setting of MAX_DRIVES > 2 won't work here.
 */
static void probe_for_drives (ide_hwif_t *hwif)
{
        unsigned int unit;

        if (check_region(hwif->io_base,8) || check_region(hwif->ctl_port,1)) {
                int msgout = 0;
                for (unit = 0; unit < MAX_DRIVES; ++unit) {
                        ide_drive_t *drive = &hwif->drives[unit];
                        if (drive->present) {
                                drive->present = 0;
                                printk("%s: ERROR, PORTS ALREADY IN USE\n", drive->name);
                                msgout = 1;
                        }
                }
                if (!msgout)
                        printk("%s: ports already in use, skipping probe\n", hwif->name);
        } else {
                unsigned long flags;
                save_flags(flags);

#if (MAX_DRIVES > 2)
                printk("%s: probing for first 2 of %d possible drives\n", hwif->name, MAX_DRIVES);
#endif
                sti();  /* needed for jiffies and irq probing */
                /*
                 * Second drive should only exist if first drive was found,
                 * but a lot of cdrom drives seem to be configured as slave-only
                 */
                for (unit = 0; unit < 2; ++unit) { /* note the hardcoded '2' */
                        ide_drive_t *drive = &hwif->drives[unit];
                        (void) probe_for_drive (drive);
                }
                for (unit = 0; unit < MAX_DRIVES; ++unit) {
                        ide_drive_t *drive = &hwif->drives[unit];
                        if (drive->present) {
                                hwif->present = 1;
                                request_region(hwif->io_base,  8, hwif->name);
                                request_region(hwif->ctl_port, 1, hwif->name);
                                break;
                        }
                }
                restore_flags(flags);
        }
}

#if SUPPORT_DTC2278
/*
 * From: andy@cercle.cts.com (Dyan Wile)
 *
 * Below is a patch for DTC-2278 - alike software-programmable controllers
 * The code enables the secondary IDE controller and the PIO4 (3?) timings on
 * the primary (EIDE). You may probably have to enable the 32-bit support to
 * get the full speed. You better get the disk interrupts disabled ( hdparm -u0
 * /dev/hd.. ) for the drives connected to the EIDE interface. (I get my 
 * filesystem  corrupted with -u1, but under heavy disk load only :-)  
 *
 * From: mlord@bnr.ca -- this chipset is now forced to use the "serialize" feature,
 * which hopefully will make it more reliable to use.. maybe it has the same bugs
 * as the CMD640B and RZ1000 ??
 */

#if SET_DTC2278_MODE4
static void sub22 (char b, char c)
{
        int i;

        for(i = 0; i < 3; ++i) {
                inb(0x3f6);
                outb_p(b,0xb0);
                inb(0x3f6);
                outb_p(c,0xb4);
                inb(0x3f6);
                if(inb(0xb4) == c) {
                        outb_p(7,0xb0);
                        inb(0x3f6);
                        return; /* success */
                }
        }
}
#endif /* SET_DTC2278_MODE4 */

static void init_dtc2278 (void)
{
        unsigned long flags;

        save_flags(flags);
        cli();
#if SET_DTC2278_MODE4
        /*
         * This enables PIO mode4 (3?) on the first interface
         */
        sub22(1,0xc3);
        sub22(0,0xa0);
#endif /* SET_DTC2278_MODE4 */
        /*
         * This enables the second interface
         */
        outb_p(4,0xb0);
        inb(0x3f6);
        outb_p(0x20,0xb4);
        inb(0x3f6);
        restore_flags(flags);
}
#endif /* SUPPORT_DTC2278 */

#ifdef SUPPORT_QD6580
/*
 * QDI QD6580 EIDE controller fast support by Colten Edwards.
 * no net access but I can be reached at pje120@cs.usask.ca
 *
 * I suppose that a IOCTL could be used for this and other
 * cards like it to modify the speed using hdparm.  Someday..
 */
static void init_qd6580 (void)
{
        unsigned long flags;

        /* looks like   0x4f is fast
         *              0x3f is medium
         *              0x2f is slower
         *              0x1f is slower yet
         *              ports are 0xb0 0xb2 and 0xb3
         */

        save_flags(flags);
        cli();
        outb_p(0x8d,0xb0);
        outb_p(0x0 ,0xb2);
        outb_p(0x4f,0xb3);      /* select "fast" 0x4f */
        inb(0x3f6);
        restore_flags(flags);
}
#endif /* SUPPORT_QD6580 */

#if SUPPORT_CMD640
/*
 * ??? fixme: 
 */
byte read_cmd640_vlb (byte port, byte reg)
{
        byte val;

        unsigned long flags;
        save_flags(flags);
        cli();
        outw(reg, port);
        val = inb(port+4);
        restore_flags(flags);
        return val;
}

void write_cmd640_vlb (byte port, byte reg, byte val)
{
        unsigned long flags;
        save_flags(flags);
        cli();
        outw(reg, port);
        outw(val, port+4);
        restore_flags(flags);
}

void init_cmd640_vlb (void)
{
        byte reg;
        unsigned short port = 0x178;

        serialized = 1;
        printk("ide: buggy CMD640 interface: serialized, ");
        reg = read_cmd640_vlb(port, 0x50);
        if (reg == 0xff || (reg & 0x90) != 0x90) {
#if TRY_CMD640_VLB_AT_0x78
                port = 0x78;
                reg = read_cmd640_vlb(port, 0x50);
                if (reg == 0xff || (reg & 0x90) != 0x90)
#endif
                {
                        disallow_unmask = 1;
                        printk("(probe failed) disabled unmasking\n");
                        return;
                }
        }
        write_cmd640_vlb(port, 0x51, read_cmd640_vlb(port, 0x51)|0xc8);
        write_cmd640_vlb(port, 0x57, read_cmd640_vlb(port, 0x57)|0x0c);
        printk("disabled read-ahead, enabled secondary\n");

}
#endif /* SUPPORT_CMD640 */

/*
 * stridx() returns the offset of c within s,
 * or -1 if c is '\0' or not found within s.
 */
static int stridx (const char *s, char c)
{
        char *i = strchr(s, c);
        return (i && c) ? i - s : -1;
}

/*
 * match_parm() does parsing for ide_setup():
 *
 * 1. the first char of s must be '='.
 * 2. if the remainder matches one of the supplied keywords,
 *     the index (1 based) of the keyword is negated and returned.
 * 3. if the remainder is a series of no more than max_vals numbers
 *     separated by commas, the numbers are saved in vals[] and a 
 *     count of how many were saved is returned.  Base10 is assumed,
 *     and base16 is allowed when prefixed with "0x".
 * 4. otherwise, zero is returned.
 */
static int match_parm (char *s, const char *keywords[], int vals[], int max_vals)
{
        static const char *decimal = "0123456789";
        static const char *hex = "0123456789abcdef";
        int i, n;

        if (*s++ == '=') {
                /*
                 * Try matching against the supplied keywords,
                 * and return -(index+1) if we match one
                 */
                for (i = 0; *keywords != NULL; ++i) {
                        if (!strcmp(s, *keywords++))
                                return -(i+1);
                }
                /*
                 * Look for a series of no more than "max_vals"
                 * numeric values separated by commas, in base10,
                 * or base16 when prefixed with "0x".  
                 * Return a count of how many were found.
                 */
                for (n = 0; (i = stridx(decimal, *s)) >= 0;) {
                        vals[n] = i;
                        while ((i = stridx(decimal, *++s)) >= 0)
                                vals[n] = (vals[n] * 10) + i;
                        if (*s == 'x' && !vals[n]) {
                                while ((i = stridx(hex, *++s)) >= 0)
                                        vals[n] = (vals[n] * 0x10) + i;
                        }
                        if (++n == max_vals)
                                break;
                        if (*s == ',')
                                ++s;
                }
                if (!*s)
                        return n;
        }
        return 0;       /* zero = nothing matched */
}

/*
 * ide_setup() gets called VERY EARLY during initialization,
 * to handle kernel "command line" strings beginning with "hdx="
 * or "ide".  Here is the complete set currently supported:
 *
 * "hdx="  is recognized for all "x" from "a" to "h", such as "hdc".
 * "idex=" is recognized for all "x" from "0" to "3", such as "ide1".
 *
 * "hdx=noprobe"        : drive may be present, but do not probe for it
 * "hdx=nowerr"         : ignore the WRERR_STAT bit on this drive
 * "hdx=cdrom"          : drive is present, and is a cdrom drive
 * "hdx=cyl,head,sect"  : disk drive is present, with specified geometry
 *
 * "idex=noprobe"       : do not attempt to access/use this interface
 * "idex=base"          : probe for an interface at the addr specified,
 *                              where "base" is usually 0x1f0 or 0x170
 *                              and "ctl" is assumed to be "base"+0x206
 * "idex=base,ctl"      : specify both base and ctl
 * "idex=base,ctl,irq"  : specify base, ctl, and irq number
 *
 * The following two are valid ONLY on ide0 or ide1,
 * and the defaults for the base,ctl ports must not be altered.
 *
 * "idex=serialize"     : do not overlap operations on ide0 and ide1.
 * "idex=dtc2278"       : enables use of DTC2278 secondary i/f
 * "idex=ht6560b"       : enables use of HT6560B secondary i/f
 * "idex=cmd640_vlb"    : required for VLB cards with the CMD640 chip
 *                        (not for PCI -- automatically detected)
 *
 * This option is valid ONLY on ide0, and the defaults for the base,ctl ports
 * must not be altered.
 *
 * "ide0=qd6580"        : select "fast" interface speed on a qd6580 interface
 */
void ide_setup (char *s)
{
        int vals[3];
        ide_hwif_t *hwif;
        ide_drive_t *drive;
        unsigned int hw, unit;
        const char max_drive = 'a' + ((MAX_HWIFS * MAX_DRIVES) - 1);
        const char max_hwif  = '0' + (MAX_HWIFS - 1);

        printk("ide_setup: %s", s);
        init_ide_data ();

        /*
         * Look for drive options:  "hdx="
         */
        if (s[0] == 'h' && s[1] == 'd' && s[2] >= 'a' && s[2] <= max_drive) {
                const char *hd_words[] = {"noprobe", "nowerr", "cdrom", "serialize", NULL};
                unit = s[2] - 'a';
                hw   = unit / MAX_DRIVES;
                unit = unit % MAX_DRIVES;
                hwif = &ide_hwifs[hw];
                drive = &hwif->drives[unit];
                switch (match_parm(&s[3], hd_words, vals, 3)) {
                        case -1: /* "noprobe" */
                                drive->noprobe = 1;
                                goto done;
                        case -2: /* "nowerr" */
                                drive->bad_wstat = BAD_R_STAT;
                                hwif->noprobe = 0;
                                goto done;
                        case -3: /* "cdrom" */
                                drive->present = 1;
                                drive->media = cdrom;
                                hwif->noprobe = 0;
                                goto done;
                        case -4: /* "serialize" */
                                printk(" -- USE \"ide%c=serialize\" INSTEAD", '0'+hw);
                                goto do_serialize;
                        case 3: /* cyl,head,sect */
                                drive->media    = disk;
                                drive->cyl      = drive->bios_cyl  = vals[0];
                                drive->head     = drive->bios_head = vals[1];
                                drive->sect     = drive->bios_sect = vals[2];
                                drive->present  = 1;
                                hwif->noprobe = 0;
                                goto done;
                        default:
                                goto bad_option;
                }
        }
        /*
         * Look for interface options:  "idex="
         */
        if (s[0] == 'i' && s[1] == 'd' && s[2] == 'e' && s[3] >= '0' && s[3] <= max_hwif) {
                const char *ide_words[] = {"noprobe", "serialize", "dtc2278", "ht6560b", "cmd640_vlb", "qd6580", NULL};
                hw = s[3] - '0';
                hwif = &ide_hwifs[hw];

                switch (match_parm(&s[4], ide_words, vals, 3)) {
#if SUPPORT_QD6580
                        case -6: /* "qd6580" */
                                if (hw != 0) goto bad_hwif;
                                init_qd6580();
                                goto done;
#endif /* SUPPORT_QD6580 */
#if SUPPORT_CMD640
                        case -5: /* "cmd640_vlb" */
                                if (hw > 1) goto bad_hwif;
                                init_cmd640_vlb();
                                goto do_serialize; /* not necessary once we implement the above */
                                break;
#endif /* SUPPORT_CMD640 */
#if SUPPORT_HT6560B
                        case -4: /* "ht6560b" */
                                if (hw > 1) goto bad_hwif;
                                /*
                                 * Using 0x1c and 0x1d apparently selects a
                                 * faster interface speed than 0x3c and 0x3d.
                                 *
                                 * Need to add an ioctl to select between them.
                                 */
                                if (check_region(0x3e6,1)) {
                                        printk(" -- HT6560 PORT 0x3e6 ALREADY IN USE");
                                        goto done;
                                }
                                request_region(0x3e6, 1, hwif->name);
                                ide_hwifs[0].select = 0x3c;
                                ide_hwifs[1].select = 0x3d;
                                goto do_serialize;
#endif /* SUPPORT_HT6560B */
#if SUPPORT_DTC2278
                        case -3: /* "dtc2278" */
                                if (hw > 1) goto bad_hwif;
                                init_dtc2278();
                                goto do_serialize;
#endif /* SUPPORT_DTC2278 */
                        case -2: /* "serialize" */
                        do_serialize:
                                if (hw > 1) goto bad_hwif;
                                serialized = 1;
                                goto done;
                        case -1: /* "noprobe" */
                                hwif->noprobe = 1;
                                goto done;
                        case 1: /* base */
                                vals[1] = vals[0] + 0x206; /* default ctl */
                        case 2: /* base,ctl */
                                vals[2] = 0;    /* default irq = probe for it */
                        case 3: /* base,ctl,irq */
                                hwif->io_base  = vals[0];
                                hwif->ctl_port = vals[1];
                                hwif->irq      = vals[2];
                                hwif->noprobe = 0;
                                goto done;
                }
        }
bad_option:
        printk(" -- BAD OPTION\n");
        return;
bad_hwif:
        printk("-- NOT SUPPORTED ON ide%d", hw);
done:
        printk("\n");
}

/*
 * This routine is called from the partition-table code in genhd.c
 * to "convert" a drive to a logical geometry with fewer than 1024 cyls
 * It mimics the method used by Ontrack Disk Manager.
 */
int ide_xlate_1024 (kdev_t i_rdev, int offset, const char *msg)
{
        ide_drive_t *drive;
        static const byte head_vals[] = {4, 8, 16, 32, 64, 128, 255, 0};
        const byte *heads = head_vals;
        unsigned long tracks;

        if ((drive = get_info_ptr(i_rdev)) == NULL || drive->id == NULL)
                return 0;

        drive->cyl  = drive->bios_cyl  = drive->id->cyls;
        drive->head = drive->bios_head = drive->id->heads;
        drive->sect = drive->bios_sect = drive->id->sectors; 
        drive->special.b.set_geometry = 1;

        tracks = drive->bios_cyl * drive->bios_head * drive->bios_sect / 63;
        drive->bios_sect = 63;
        while (drive->bios_cyl >= 1024) {
                drive->bios_head = *heads;
                drive->bios_cyl = tracks / drive->bios_head;
                if (0 == *++heads)
                        break;
        }
        if (offset) {
#if FAKE_FDISK_FOR_EZDRIVE
                if (offset == -1)
                        drive->ezdrive = 1;
                else
#endif /* FAKE_FDISK_FOR_EZDRIVE */
                {
                        drive->sect0 = 63;
                        drive->bios_cyl = (tracks - 1) / drive->bios_head;
                }
        }
        drive->part[0].nr_sects = current_capacity(drive);
        printk("%s [%d/%d/%d]", msg, drive->bios_cyl, drive->bios_head, drive->bios_sect);
        return 1;
}

/*
 * We query CMOS about hard disks : it could be that we have a SCSI/ESDI/etc
 * controller that is BIOS compatible with ST-506, and thus showing up in our
 * BIOS table, but not register compatible, and therefore not present in CMOS.
 *
 * Furthermore, we will assume that our ST-506 drives <if any> are the primary
 * drives in the system -- the ones reflected as drive 1 or 2.  The first
 * drive is stored in the high nibble of CMOS byte 0x12, the second in the low
 * nibble.  This will be either a 4 bit drive type or 0xf indicating use byte
 * 0x19 for an 8 bit type, drive 1, 0x1a for drive 2 in CMOS.  A non-zero value 
 * means we have an AT controller hard disk for that drive.
 *
 * Of course, there is no guarantee that either drive is actually on the
 * "primary" IDE interface, but we don't bother trying to sort that out here.
 * If a drive is not actually on the primary interface, then these parameters
 * will be ignored.  This results in the user having to supply the logical
 * drive geometry as a boot parameter for each drive not on the primary i/f.
 *
 * The only "perfect" way to handle this would be to modify the setup.[cS] code
 * to do BIOS calls Int13h/Fn08h and Int13h/Fn48h to get all of the drive info
 * for us during initialization.  I have the necessary docs -- any takers?  -ml
 */

static void probe_cmos_for_drives (ide_hwif_t *hwif)
{
#ifdef __i386__
        extern struct drive_info_struct drive_info;
        byte cmos_disks, *BIOS = (byte *) &drive_info;
        int unit;

        outb_p(0x12,0x70);              /* specify CMOS address 0x12 */
        cmos_disks = inb_p(0x71);       /* read the data from 0x12 */
        /* Extract drive geometry from CMOS+BIOS if not already setup */
        for (unit = 0; unit < MAX_DRIVES; ++unit) {
                ide_drive_t *drive = &hwif->drives[unit];
                if ((cmos_disks & (0xf0 >> (unit*4))) && !drive->present) {
                        drive->cyl   = drive->bios_cyl  = *(unsigned short *)BIOS;
                        drive->head  = drive->bios_head = *(BIOS+2);
                        drive->sect  = drive->bios_sect = *(BIOS+14);
                        drive->ctl   = *(BIOS+8);
                        drive->present = 1;
                }
                BIOS += 16;
        }
#endif
}

/*
 * This routine sets up the irq for an ide interface, and creates a new
 * hwgroup for the irq/hwif if none was previously assigned.
 *
 * The SA_INTERRUPT in sa_flags means ide_intr() is always entered with
 * interrupts completely disabled.  This can be bad for interrupt latency,
 * but anything else has led to problems on some machines.  We re-enable
 * interrupts as much as we can safely do in most places.
 */
static int init_irq (ide_hwif_t *hwif)
{
        unsigned long flags;
        int irq = hwif->irq;
        ide_hwgroup_t *hwgroup = irq_to_hwgroup[irq];

        save_flags(flags);
        cli();

        /*
         * Grab the irq if we don't already have it from a previous hwif
         */
        if (hwgroup == NULL)  {
                if (request_irq(irq, ide_intr, SA_INTERRUPT|SA_SAMPLE_RANDOM, hwif->name)) {
                        restore_flags(flags);
                        printk(" -- FAILED!");
                        return 1;
                }
        }
        /*
         * Check for serialization with ide1.
         * This code depends on us having already taken care of ide1.
         */
        if (serialized && hwif->name[3] == '0' && ide_hwifs[1].present)
                hwgroup = ide_hwifs[1].hwgroup;
        /*
         * If this is the first interface in a group,
         * then we need to create the hwgroup structure
         */
        if (hwgroup == NULL) {
                hwgroup = kmalloc (sizeof(ide_hwgroup_t), GFP_KERNEL);
                hwgroup->hwif    = hwif->next = hwif;
                hwgroup->rq      = NULL;
                hwgroup->handler = NULL;
                hwgroup->drive   = NULL;
                hwgroup->reset_timeout = 0;
#ifdef CONFIG_BLK_DEV_IDECD
                hwgroup->doing_atapi_reset = 0;
#endif /* CONFIG_BLK_DEV_IDECD */
                init_timer(&hwgroup->timer);
                hwgroup->timer.function = &timer_expiry;
                hwgroup->timer.data = (unsigned long) hwgroup;
        } else {
                hwif->next = hwgroup->hwif->next;
                hwgroup->hwif->next = hwif;
        }
        hwif->hwgroup = hwgroup;
        irq_to_hwgroup[irq] = hwgroup;

        restore_flags(flags);   /* safe now that hwif->hwgroup is set up */

        printk("%s at 0x%03x-0x%03x,0x%03x on irq %d", hwif->name,
                hwif->io_base, hwif->io_base+7, hwif->ctl_port, irq);
        if (hwgroup->hwif != hwif)
                printk(" (serialized with %s)", hwgroup->hwif->name);
        printk("\n");
        return 0;
}

static struct file_operations ide_fops = {
        NULL,                   /* lseek - default */
        block_read,             /* read - general block-dev read */
        block_write,            /* write - general block-dev write */
        NULL,                   /* readdir - bad */
        NULL,                   /* select */
        ide_ioctl,              /* ioctl */
        NULL,                   /* mmap */
        ide_open,               /* open */
        ide_release,            /* release */
        block_fsync             /* fsync */
        ,NULL,                  /* fasync */
        ide_check_media_change, /* check_media_change */
        revalidate_disk         /* revalidate */
};

#ifdef CONFIG_PCI

void ide_pci_access_error (int rc)
{
        printk("ide: pcibios access failed - %s\n", pcibios_strerror(rc));
}

#if SUPPORT_RZ1000 || SUPPORT_CMD640
void buggy_interface_fallback (int rc)
{
        ide_pci_access_error (rc);
        serialized = 1;
        disallow_unmask = 1;
        printk("serialized, disabled unmasking\n");
}
#endif /* SUPPORT_RZ1000 || SUPPORT_CMD640 */

#if SUPPORT_RZ1000
void init_rz1000 (byte bus, byte fn)
{
        int rc;
        unsigned short reg;

        printk("ide: buggy RZ1000 interface: ");
        if ((rc = pcibios_read_config_word (bus, fn, PCI_COMMAND, &reg))) {
                ide_pci_access_error (rc);
        } else if (!(reg & 1)) {
                printk("not enabled\n");
        } else {
                if ((rc = pcibios_read_config_word(bus, fn, 0x40, &reg))
                 || (rc =  pcibios_write_config_word(bus, fn, 0x40, reg & 0xdfff)))
                        buggy_interface_fallback (rc);
                else
                        printk("disabled read-ahead\n");
        }
}
#endif /* SUPPORT_RZ1000 */

#if SUPPORT_CMD640
void init_cmd640 (byte bus, byte fn)
{
        int rc;
        unsigned char reg;

        serialized = 1;
        printk("ide: buggy CMD640 interface: ");

#if 0   /* funny.. the cmd640b I tried this on claimed to not be enabled.. */
        unsigned short sreg;
        if ((rc = pcibios_read_config_word (bus, fn, PCI_COMMAND, &sreg))) {
                ide_pci_access_error (rc);
        } else if (!(sreg & 1)) {
                printk("not enabled\n");
        } else {

        /*
         * The first part is undocumented magic from the DOS driver.
         * According to the datasheet, there is no port 0x5b on the cmd640.
         */
        (void) pcibios_write_config_byte(bus, fn, 0x5b, 0xbd);
        if (pcibios_write_config_byte(bus, fn, 0x5b, 0xbd) != 0xbd)
                printk("init_cmd640: huh? 0x5b read back wrong\n");
        (void) pcibios_write_config_byte(bus, fn, 0x5b, 0);
#endif /* 0 */
        /*
         * The rest is from the cmd640b datasheet.
         */
        if ((rc = pcibios_read_config_byte(bus, fn, 0x51, &reg))
         || (rc =  pcibios_write_config_byte(bus, fn, 0x51, reg | 0xc0)) /* 0xc8 to enable 2nd i/f */
         || (rc =  pcibios_read_config_byte(bus, fn, 0x57, &reg))
         || (rc =  pcibios_write_config_byte(bus, fn, 0x57, reg | 0x0c)))
                buggy_interface_fallback (rc);
        else
                printk("serialized, disabled read-ahead\n");
}
#endif /* SUPPORT_CMD640 */

typedef void (ide_pci_init_proc_t)(byte, byte);

/*
 * ide_probe_pci() scans PCI for a specific vendor/device function,
 * and invokes the supplied init routine for each instance detected.
 */
static void ide_probe_pci (unsigned short vendor, unsigned short device, ide_pci_init_proc_t *init, int func_adj)
{
        unsigned long flags;
        unsigned index;
        byte fn, bus;

        save_flags(flags);
        cli();
        for (index = 0; !pcibios_find_device (vendor, device, index, &bus, &fn); ++index) {
                init (bus, fn + func_adj);
        }
        restore_flags(flags);
}

/*
 * ide_init_pci() finds/initializes "known" PCI IDE interfaces
 * 
 * This routine should ideally be using pcibios_find_class() to find
 * all IDE interfaces, but that function causes some systems to "go weird".
 */
static void ide_init_pci (void)
{
#if SUPPORT_RZ1000
        ide_probe_pci (PCI_VENDOR_ID_PCTECH, PCI_DEVICE_ID_PCTECH_RZ1000, &init_rz1000, 0);
#endif
#if SUPPORT_CMD640
        ide_probe_pci (PCI_VENDOR_ID_CMD, PCI_DEVICE_ID_CMD_640, &init_cmd640, 0);
#endif
#ifdef CONFIG_BLK_DEV_TRITON
        /*
         * Apparently the BIOS32 services on Intel motherboards are buggy,
         * and won't find the PCI_DEVICE_ID_INTEL_82371_1 for us.
         * So we instead search for PCI_DEVICE_ID_INTEL_82371_0, and then add 1.
         */
        ide_probe_pci (PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82371_0, &ide_init_triton, 1);
#endif
}
#endif /* CONFIG_PCI */

/*
 * This is gets invoked once during initialization, to set *everything* up
 */
int ide_init (void)
{
        int h;

        init_ide_data ();
        /*
         * First, we determine what hardware is present
         */

#ifdef CONFIG_PCI
        /*
         * Find/initialize PCI IDE interfaces
         */
        if (pcibios_present())
                ide_init_pci ();
#endif /* CONFIG_PCI */

        /*
         * Probe for drives in the usual way.. CMOS/BIOS, then poke at ports
         */
        for (h = 0; h < MAX_HWIFS; ++h) {
                ide_hwif_t *hwif = &ide_hwifs[h];
                if (!hwif->noprobe) {
                        if (hwif->io_base == HD_DATA)
                                probe_cmos_for_drives (hwif);
                        probe_for_drives (hwif);
                }
                if (hwif->present) {
                        if (!hwif->irq) {
                                if (!(hwif->irq = default_irqs[h])) {
                                        printk("%s: DISABLED, NO IRQ\n", hwif->name);
                                        hwif->present = 0;
                                        continue;
                                }
                        }
#ifdef CONFIG_BLK_DEV_HD
                        if (hwif->irq == HD_IRQ && hwif->io_base != HD_DATA) {
                                printk("%s: CANNOT SHARE IRQ WITH OLD HARDDISK DRIVER (hd.c)\n", hwif->name);
                                hwif->present = 0;
                        }
#endif /* CONFIG_BLK_DEV_HD */
                }
        }

        /*
         * Now we try to set up irqs and major devices for what was found
         */
        for (h = MAX_HWIFS-1; h >= 0; --h) {
                void (*rfn)(void);
                ide_hwif_t *hwif = &ide_hwifs[h];
                if (!hwif->present)
                        continue;
                hwif->present = 0; /* we set it back to 1 if all is ok below */
                switch (hwif->major) {
                        case IDE0_MAJOR: rfn = &do_ide0_request; break;
                        case IDE1_MAJOR: rfn = &do_ide1_request; break;
                        case IDE2_MAJOR: rfn = &do_ide2_request; break;
                        case IDE3_MAJOR: rfn = &do_ide3_request; break;
                        default:
                                printk("%s: request_fn NOT DEFINED\n", hwif->name);
                                continue;
                }
                if (register_blkdev (hwif->major, hwif->name, &ide_fops)) {
                        printk("%s: UNABLE TO GET MAJOR NUMBER %d\n", hwif->name, hwif->major);
                } else if (init_irq (hwif)) {
                        printk("%s: UNABLE TO GET IRQ %d\n", hwif->name, hwif->irq);
                        (void) unregister_blkdev (hwif->major, hwif->name);
                } else {
                        init_gendisk(hwif);
                        blk_dev[hwif->major].request_fn = rfn;
                        read_ahead[hwif->major] = 8;    /* (4kB) */
                        hwif->present = 1;      /* success */
                }
        }
        return 0;
}