/*
 *  linux/drivers/ide/ide-probe.c       Version 1.11    Mar 05, 2003
 *
 *  Copyright (C) 1994-1998  Linus Torvalds & authors (see below)
 */

/*
 *  Mostly written by Mark Lord <mlord@pobox.com>
 *                and Gadi Oxman <gadio@netvision.net.il>
 *                and Andre Hedrick <andre@linux-ide.org>
 *
 *  See linux/MAINTAINERS for address of current maintainer.
 *
 * This is the IDE probe module, as evolved from hd.c and ide.c.
 *
 * -- increase WAIT_PIDENTIFY to avoid CD-ROM locking at boot
 *       by Andrea Arcangeli
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/timer.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/major.h>
#include <linux/errno.h>
#include <linux/genhd.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/ide.h>
#include <linux/spinlock.h>
#include <linux/kmod.h>
#include <linux/pci.h>
#include <linux/scatterlist.h>

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

/**
 *      generic_id              -       add a generic drive id
 *      @drive: drive to make an ID block for
 *      
 *      Add a fake id field to the drive we are passed. This allows
 *      use to skip a ton of NULL checks (which people always miss) 
 *      and make drive properties unconditional outside of this file
 */
 
static void generic_id(ide_drive_t *drive)
{
        drive->id->cyls = drive->cyl;
        drive->id->heads = drive->head;
        drive->id->sectors = drive->sect;
        drive->id->cur_cyls = drive->cyl;
        drive->id->cur_heads = drive->head;
        drive->id->cur_sectors = drive->sect;
}

static void ide_disk_init_chs(ide_drive_t *drive)
{
        struct hd_driveid *id = drive->id;

        /* Extract geometry if we did not already have one for the drive */
        if (!drive->cyl || !drive->head || !drive->sect) {
                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) {
                drive->cyl  = id->cur_cyls;
                drive->head = id->cur_heads;
                drive->sect = id->cur_sectors;
        }

        /* Use physical geometry if what we have still makes no sense */
        if (drive->head > 16 && id->heads && id->heads <= 16) {
                drive->cyl  = id->cyls;
                drive->head = id->heads;
                drive->sect = id->sectors;
        }
}

static void ide_disk_init_mult_count(ide_drive_t *drive)
{
        struct hd_driveid *id = drive->id;

        drive->mult_count = 0;
        if (id->max_multsect) {
#ifdef CONFIG_IDEDISK_MULTI_MODE
                id->multsect = ((id->max_multsect/2) > 1) ? id->max_multsect : 0;
                id->multsect_valid = id->multsect ? 1 : 0;
                drive->mult_req = id->multsect_valid ? id->max_multsect : INITIAL_MULT_COUNT;
                drive->special.b.set_multmode = drive->mult_req ? 1 : 0;
#else   /* original, pre IDE-NFG, per request of AC */
                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;
#endif
        }
}

/**
 *      do_identify     -       identify a drive
 *      @drive: drive to identify 
 *      @cmd: command used
 *
 *      Called when we have issued a drive identify command to
 *      read and parse the results. This function is run with
 *      interrupts disabled. 
 */
 
static inline void do_identify (ide_drive_t *drive, u8 cmd)
{
        ide_hwif_t *hwif = HWIF(drive);
        int bswap = 1;
        struct hd_driveid *id;

        id = drive->id;
        /* read 512 bytes of id info */
        hwif->ata_input_data(drive, id, SECTOR_WORDS);

        drive->id_read = 1;
        local_irq_enable();
        ide_fix_driveid(id);

#if defined (CONFIG_SCSI_EATA_PIO) || defined (CONFIG_SCSI_EATA)
        /*
         * EATA SCSI controllers do a hardware ATA emulation:
         * Ignore them if there is a driver for them available.
         */
        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);
                goto err_misc;
        }
#endif /* CONFIG_SCSI_EATA || CONFIG_SCSI_EATA_PIO */

        /*
         *  WIN_IDENTIFY returns little-endian info,
         *  WIN_PIDENTIFY *usually* returns little-endian info.
         */
        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 */
                        /* Vertos drives may still be weird */
                        bswap ^= 1;     
        }
        ide_fixstring(id->model,     sizeof(id->model),     bswap);
        ide_fixstring(id->fw_rev,    sizeof(id->fw_rev),    bswap);
        ide_fixstring(id->serial_no, sizeof(id->serial_no), bswap);

        /* we depend on this a lot! */
        id->model[sizeof(id->model)-1] = '\0';

        if (strstr(id->model, "E X A B Y T E N E S T"))
                goto err_misc;

        printk("%s: %s, ", drive->name, id->model);
        drive->present = 1;
        drive->dead = 0;

        /*
         * Check for an ATAPI device
         */
        if (cmd == WIN_PIDENTIFY) {
                u8 type = (id->config >> 8) & 0x1f;
                printk("ATAPI ");
                switch (type) {
                        case ide_floppy:
                                if (!strstr(id->model, "CD-ROM")) {
                                        if (!strstr(id->model, "oppy") &&
                                            !strstr(id->model, "poyp") &&
                                            !strstr(id->model, "ZIP"))
                                                printk("cdrom or floppy?, assuming ");
                                        if (drive->media != ide_cdrom) {
                                                printk ("FLOPPY");
                                                drive->removable = 1;
                                                break;
                                        }
                                }
                                /* Early cdrom models used zero */
                                type = ide_cdrom;
                        case ide_cdrom:
                                drive->removable = 1;
#ifdef CONFIG_PPC
                                /* kludge for Apple PowerBook internal zip */
                                if (!strstr(id->model, "CD-ROM") &&
                                    strstr(id->model, "ZIP")) {
                                        printk ("FLOPPY");
                                        type = ide_floppy;
                                        break;
                                }
#endif
                                printk ("CD/DVD-ROM");
                                break;
                        case ide_tape:
                                printk ("TAPE");
                                break;
                        case ide_optical:
                                printk ("OPTICAL");
                                drive->removable = 1;
                                break;
                        default:
                                printk("UNKNOWN (type %d)", type);
                                break;
                }
                printk (" drive\n");
                drive->media = type;
                /* an ATAPI device ignores DRDY */
                drive->ready_stat = 0;
                return;
        }

        /*
         * Not an ATAPI device: looks like a "regular" hard disk
         */

        /*
         * 0x848a = CompactFlash device
         * These are *not* removable in Linux definition of the term
         */

        if ((id->config != 0x848a) && (id->config & (1<<7)))
                drive->removable = 1;

        drive->media = ide_disk;
        printk("%s DISK drive\n", (id->config == 0x848a) ? "CFA" : "ATA" );
        QUIRK_LIST(drive);
        return;

err_misc:
        kfree(id);
        drive->present = 0;
        return;
}

/**
 *      actual_try_to_identify  -       send ata/atapi identify
 *      @drive: drive to identify
 *      @cmd: command to use
 *
 *      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 actual_try_to_identify (ide_drive_t *drive, u8 cmd)
{
        ide_hwif_t *hwif = HWIF(drive);
        int rc;
        unsigned long hd_status;
        unsigned long timeout;
        u8 s = 0, a = 0;

        /* take a deep breath */
        msleep(50);

        if (IDE_CONTROL_REG) {
                a = hwif->INB(IDE_ALTSTATUS_REG);
                s = hwif->INB(IDE_STATUS_REG);
                if ((a ^ s) & ~INDEX_STAT) {
                        printk(KERN_INFO "%s: probing with STATUS(0x%02x) instead of "
                                "ALTSTATUS(0x%02x)\n", drive->name, s, a);
                        /* ancient Seagate drives, broken interfaces */
                        hd_status = IDE_STATUS_REG;
                } else {
                        /* use non-intrusive polling */
                        hd_status = IDE_ALTSTATUS_REG;
                }
        } else
                hd_status = IDE_STATUS_REG;

        /* set features register for atapi
         * identify command to be sure of reply
         */
        if ((cmd == WIN_PIDENTIFY))
                /* disable dma & overlap */
                hwif->OUTB(0, IDE_FEATURE_REG);

        /* ask drive for ID */
        hwif->OUTB(cmd, IDE_COMMAND_REG);

        timeout = ((cmd == WIN_IDENTIFY) ? WAIT_WORSTCASE : WAIT_PIDENTIFY) / 2;
        timeout += jiffies;
        do {
                if (time_after(jiffies, timeout)) {
                        /* drive timed-out */
                        return 1;
                }
                /* give drive a breather */
                msleep(50);
        } while ((hwif->INB(hd_status)) & BUSY_STAT);

        /* wait for IRQ and DRQ_STAT */
        msleep(50);
        if (OK_STAT((hwif->INB(IDE_STATUS_REG)), DRQ_STAT, BAD_R_STAT)) {
                unsigned long flags;

                /* local CPU only; some systems need this */
                local_irq_save(flags);
                /* drive returned ID */
                do_identify(drive, cmd);
                /* drive responded with ID */
                rc = 0;
                /* clear drive IRQ */
                (void) hwif->INB(IDE_STATUS_REG);
                local_irq_restore(flags);
        } else {
                /* drive refused ID */
                rc = 2;
        }
        return rc;
}

/**
 *      try_to_identify -       try to identify a drive
 *      @drive: drive to probe
 *      @cmd: command to use
 *
 *      Issue the identify command and then do IRQ probing to
 *      complete the identification when needed by finding the
 *      IRQ the drive is attached to
 */
 
static int try_to_identify (ide_drive_t *drive, u8 cmd)
{
        ide_hwif_t *hwif = HWIF(drive);
        int retval;
        int autoprobe = 0;
        unsigned long cookie = 0;

        /*
         * Disable device irq unless we need to
         * probe for it. Otherwise we'll get spurious
         * interrupts during the identify-phase that
         * the irq handler isn't expecting.
         */
        if (IDE_CONTROL_REG) {
                u8 ctl = drive->ctl | 2;
                if (!hwif->irq) {
                        autoprobe = 1;
                        cookie = probe_irq_on();
                        /* enable device irq */
                        ctl &= ~2;
                }
                hwif->OUTB(ctl, IDE_CONTROL_REG);
        }

        retval = actual_try_to_identify(drive, cmd);

        if (autoprobe) {
                int irq;
                /* mask device irq */
                hwif->OUTB(drive->ctl|2, IDE_CONTROL_REG);
                /* clear drive IRQ */
                (void) hwif->INB(IDE_STATUS_REG);
                udelay(5);
                irq = probe_irq_off(cookie);
                if (!hwif->irq) {
                        if (irq > 0) {
                                hwif->irq = irq;
                        } else {
                                /* Mmmm.. multiple IRQs..
                                 * don't know which was ours
                                 */
                                printk("%s: IRQ probe failed (0x%lx)\n",
                                        drive->name, cookie);
                        }
                }
        }
        return retval;
}


/**
 *      do_probe                -       probe an IDE device
 *      @drive: drive to probe
 *      @cmd: command to use
 *
 *      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, u8 cmd)
{
        int rc;
        ide_hwif_t *hwif = HWIF(drive);

        if (drive->present) {
                /* avoid waiting for inappropriate probes */
                if ((drive->media != ide_disk) && (cmd == WIN_IDENTIFY))
                        return 4;
        }
#ifdef DEBUG
        printk("probing for %s: present=%d, media=%d, probetype=%s\n",
                drive->name, drive->present, drive->media,
                (cmd == WIN_IDENTIFY) ? "ATA" : "ATAPI");
#endif

        /* needed for some systems
         * (e.g. crw9624 as drive0 with disk as slave)
         */
        msleep(50);
        SELECT_DRIVE(drive);
        msleep(50);
        if (hwif->INB(IDE_SELECT_REG) != drive->select.all && !drive->present) {
                if (drive->select.b.unit != 0) {
                        /* exit with drive0 selected */
                        SELECT_DRIVE(&hwif->drives[0]);
                        /* allow BUSY_STAT to assert & clear */
                        msleep(50);
                }
                /* no i/f present: mmm.. this should be a 4 -ml */
                return 3;
        }

        if (OK_STAT((hwif->INB(IDE_STATUS_REG)), READY_STAT, BUSY_STAT) ||
            drive->present || cmd == WIN_PIDENTIFY) {
                /* send cmd and wait */
                if ((rc = try_to_identify(drive, cmd))) {
                        /* failed: try again */
                        rc = try_to_identify(drive,cmd);
                }
                if (hwif->INB(IDE_STATUS_REG) == (BUSY_STAT|READY_STAT))
                        return 4;

                if ((rc == 1 && cmd == WIN_PIDENTIFY) &&
                        ((drive->autotune == IDE_TUNE_DEFAULT) ||
                        (drive->autotune == IDE_TUNE_AUTO))) {
                        unsigned long timeout;
                        printk("%s: no response (status = 0x%02x), "
                                "resetting drive\n", drive->name,
                                hwif->INB(IDE_STATUS_REG));
                        msleep(50);
                        hwif->OUTB(drive->select.all, IDE_SELECT_REG);
                        msleep(50);
                        hwif->OUTB(WIN_SRST, IDE_COMMAND_REG);
                        timeout = jiffies;
                        while (((hwif->INB(IDE_STATUS_REG)) & BUSY_STAT) &&
                               time_before(jiffies, timeout + WAIT_WORSTCASE))
                                msleep(50);
                        rc = try_to_identify(drive, cmd);
                }
                if (rc == 1)
                        printk("%s: no response (status = 0x%02x)\n",
                                drive->name, hwif->INB(IDE_STATUS_REG));
                /* ensure drive irq is clear */
                (void) hwif->INB(IDE_STATUS_REG);
        } else {
                /* not present or maybe ATAPI */
                rc = 3;
        }
        if (drive->select.b.unit != 0) {
                /* exit with drive0 selected */
                SELECT_DRIVE(&hwif->drives[0]);
                msleep(50);
                /* ensure drive irq is clear */
                (void) hwif->INB(IDE_STATUS_REG);
        }
        return rc;
}

/*
 *
 */
static void enable_nest (ide_drive_t *drive)
{
        ide_hwif_t *hwif = HWIF(drive);
        unsigned long timeout;

        printk("%s: enabling %s -- ", hwif->name, drive->id->model);
        SELECT_DRIVE(drive);
        msleep(50);
        hwif->OUTB(EXABYTE_ENABLE_NEST, IDE_COMMAND_REG);
        timeout = jiffies + WAIT_WORSTCASE;
        do {
                if (time_after(jiffies, timeout)) {
                        printk("failed (timeout)\n");
                        return;
                }
                msleep(50);
        } while ((hwif->INB(IDE_STATUS_REG)) & BUSY_STAT);

        msleep(50);

        if (!OK_STAT((hwif->INB(IDE_STATUS_REG)), 0, BAD_STAT)) {
                printk("failed (status = 0x%02x)\n", hwif->INB(IDE_STATUS_REG));
        } else {
                printk("success\n");
        }

        /* if !(success||timed-out) */
        if (do_probe(drive, WIN_IDENTIFY) >= 2) {
                /* look for ATAPI device */
                (void) do_probe(drive, WIN_PIDENTIFY);
        }
}

/**
 *      probe_for_drives        -       upper level drive probe
 *      @drive: drive to probe for
 *
 *      probe_for_drive() tests for existence of a given drive using do_probe()
 *      and presents things to the user as needed.
 *
 *      Returns:        0  no device was found
 *                      1  device was found (note: drive->present might
 *                         still be 0)
 */
 
static inline u8 probe_for_drive (ide_drive_t *drive)
{
        /*
         *      In order to keep things simple we have an id
         *      block for all drives at all times. If the device
         *      is pre ATA or refuses ATA/ATAPI identify we
         *      will add faked data to this.
         *
         *      Also note that 0 everywhere means "can't do X"
         */
 
        drive->id = kzalloc(SECTOR_WORDS *4, GFP_KERNEL);
        drive->id_read = 0;
        if(drive->id == NULL)
        {
                printk(KERN_ERR "ide: out of memory for id data.\n");
                return 0;
        }
        strcpy(drive->id->model, "UNKNOWN");
        
        /* skip probing? */
        if (!drive->noprobe)
        {
                /* if !(success||timed-out) */
                if (do_probe(drive, WIN_IDENTIFY) >= 2) {
                        /* look for ATAPI device */
                        (void) do_probe(drive, WIN_PIDENTIFY);
                }
                if (!drive->present)
                        /* drive not found */
                        return 0;
                if (strstr(drive->id->model, "E X A B Y T E N E S T"))
                        enable_nest(drive);
        
                /* identification failed? */
                if (!drive->id_read) {
                        if (drive->media == ide_disk) {
                                printk(KERN_INFO "%s: non-IDE drive, CHS=%d/%d/%d\n",
                                        drive->name, drive->cyl,
                                        drive->head, drive->sect);
                        } else if (drive->media == ide_cdrom) {
                                printk(KERN_INFO "%s: ATAPI cdrom (?)\n", drive->name);
                        } else {
                                /* nuke it */
                                printk(KERN_WARNING "%s: Unknown device on bus refused identification. Ignoring.\n", drive->name);
                                drive->present = 0;
                        }
                }
                /* drive was found */
        }
        if(!drive->present)
                return 0;
        /* The drive wasn't being helpful. Add generic info only */
        if (drive->id_read == 0) {
                generic_id(drive);
                return 1;
        }

        if (drive->media == ide_disk) {
                ide_disk_init_chs(drive);
                ide_disk_init_mult_count(drive);
        }

        return drive->present;
}

static void hwif_release_dev (struct device *dev)
{
        ide_hwif_t *hwif = container_of(dev, ide_hwif_t, gendev);

        complete(&hwif->gendev_rel_comp);
}

static void hwif_register (ide_hwif_t *hwif)
{
        int ret;

        /* register with global device tree */
        strlcpy(hwif->gendev.bus_id,hwif->name,BUS_ID_SIZE);
        hwif->gendev.driver_data = hwif;
        if (hwif->gendev.parent == NULL) {
                if (hwif->pci_dev)
                        hwif->gendev.parent = &hwif->pci_dev->dev;
                else
                        /* Would like to do = &device_legacy */
                        hwif->gendev.parent = NULL;
        }
        hwif->gendev.release = hwif_release_dev;
        ret = device_register(&hwif->gendev);
        if (ret < 0)
                printk(KERN_WARNING "IDE: %s: device_register error: %d\n",
                        __FUNCTION__, ret);
}

static int wait_hwif_ready(ide_hwif_t *hwif)
{
        int unit, rc;

        printk(KERN_DEBUG "Probing IDE interface %s...\n", hwif->name);

        /* Let HW settle down a bit from whatever init state we
         * come from */
        mdelay(2);

        /* Wait for BSY bit to go away, spec timeout is 30 seconds,
         * I know of at least one disk who takes 31 seconds, I use 35
         * here to be safe
         */
        rc = ide_wait_not_busy(hwif, 35000);
        if (rc)
                return rc;

        /* Now make sure both master & slave are ready */
        for (unit = 0; unit < MAX_DRIVES; unit++) {
                ide_drive_t *drive = &hwif->drives[unit];

                /* Ignore disks that we will not probe for later. */
                if (!drive->noprobe || drive->present) {
                        SELECT_DRIVE(drive);
                        if (IDE_CONTROL_REG)
                                hwif->OUTB(drive->ctl, IDE_CONTROL_REG);
                        mdelay(2);
                        rc = ide_wait_not_busy(hwif, 35000);
                        if (rc)
                                goto out;
                } else
                        printk(KERN_DEBUG "%s: ide_wait_not_busy() skipped\n",
                                          drive->name);
        }
out:
        /* Exit function with master reselected (let's be sane) */
        if (unit)
                SELECT_DRIVE(&hwif->drives[0]);

        return rc;
}

/**
 *      ide_undecoded_slave     -       look for bad CF adapters
 *      @hwif: interface
 *
 *      Analyse the drives on the interface and attempt to decide if we
 *      have the same drive viewed twice. This occurs with crap CF adapters
 *      and PCMCIA sometimes.
 */

void ide_undecoded_slave(ide_hwif_t *hwif)
{
        ide_drive_t *drive0 = &hwif->drives[0];
        ide_drive_t *drive1 = &hwif->drives[1];

        if (drive0->present == 0 || drive1->present == 0)
                return;

        /* If the models don't match they are not the same product */
        if (strcmp(drive0->id->model, drive1->id->model))
                return;

        /* Serial numbers do not match */
        if (strncmp(drive0->id->serial_no, drive1->id->serial_no, 20))
                return;

        /* No serial number, thankfully very rare for CF */
        if (drive0->id->serial_no[0] == 0)
                return;

        /* Appears to be an IDE flash adapter with decode bugs */
        printk(KERN_WARNING "ide-probe: ignoring undecoded slave\n");

        drive1->present = 0;
}

EXPORT_SYMBOL_GPL(ide_undecoded_slave);

/*
 * 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_hwif(ide_hwif_t *hwif)
{
        unsigned long flags;
        unsigned int irqd;
        int unit;

        if (hwif->noprobe)
                return;

        if ((hwif->chipset != ide_4drives || !hwif->mate || !hwif->mate->present) &&
            (ide_hwif_request_regions(hwif))) {
                u16 msgout = 0;
                for (unit = 0; unit < MAX_DRIVES; ++unit) {
                        ide_drive_t *drive = &hwif->drives[unit];
                        if (drive->present) {
                                drive->present = 0;
                                printk(KERN_ERR "%s: ERROR, PORTS ALREADY IN USE\n",
                                        drive->name);
                                msgout = 1;
                        }
                }
                if (!msgout)
                        printk(KERN_ERR "%s: ports already in use, skipping probe\n",
                                hwif->name);
                return; 
        }

        /*
         * We must always disable IRQ, as probe_for_drive will assert IRQ, but
         * we'll install our IRQ driver much later...
         */
        irqd = hwif->irq;
        if (irqd)
                disable_irq(hwif->irq);

        local_irq_set(flags);

        /* This is needed on some PPCs and a bunch of BIOS-less embedded
         * platforms. Typical cases are:
         * 
         *  - The firmware hard reset the disk before booting the kernel,
         *    the drive is still doing it's poweron-reset sequence, that
         *    can take up to 30 seconds
         *  - The firmware does nothing (or no firmware), the device is
         *    still in POST state (same as above actually).
         *  - Some CD/DVD/Writer combo drives tend to drive the bus during
         *    their reset sequence even when they are non-selected slave
         *    devices, thus preventing discovery of the main HD
         *    
         *  Doing this wait-for-busy should not harm any existing configuration
         *  (at least things won't be worse than what current code does, that
         *  is blindly go & talk to the drive) and fix some issues like the
         *  above.
         *  
         *  BenH.
         */
        if (wait_hwif_ready(hwif) == -EBUSY)
                printk(KERN_DEBUG "%s: Wait for ready failed before probe !\n", hwif->name);

        /*
         * Need to probe slave device first to make it release PDIAG-.
         */
        for (unit = MAX_DRIVES - 1; unit >= 0; unit--) {
                ide_drive_t *drive = &hwif->drives[unit];
                drive->dn = (hwif->channel ? 2 : 0) + unit;
                (void) probe_for_drive(drive);
                if (drive->present && !hwif->present) {
                        hwif->present = 1;
                        if (hwif->chipset != ide_4drives ||
                            !hwif->mate || 
                            !hwif->mate->present) {
                                hwif_register(hwif);
                        }
                }
        }
        if (hwif->io_ports[IDE_CONTROL_OFFSET] && hwif->reset) {
                unsigned long timeout = jiffies + WAIT_WORSTCASE;
                u8 stat;

                printk(KERN_WARNING "%s: reset\n", hwif->name);
                hwif->OUTB(12, hwif->io_ports[IDE_CONTROL_OFFSET]);
                udelay(10);
                hwif->OUTB(8, hwif->io_ports[IDE_CONTROL_OFFSET]);
                do {
                        msleep(50);
                        stat = hwif->INB(hwif->io_ports[IDE_STATUS_OFFSET]);
                } while ((stat & BUSY_STAT) && time_after(timeout, jiffies));

        }
        local_irq_restore(flags);
        /*
         * Use cached IRQ number. It might be (and is...) changed by probe
         * code above
         */
        if (irqd)
                enable_irq(irqd);

        if (!hwif->present) {
                ide_hwif_release_regions(hwif);
                return;
        }

        if (hwif->fixup)
                hwif->fixup(hwif);

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

                if (drive->present) {
                        if (drive->autotune == IDE_TUNE_AUTO)
                                ide_set_max_pio(drive);

                        if (drive->autotune != IDE_TUNE_DEFAULT &&
                            drive->autotune != IDE_TUNE_AUTO)
                                continue;

                        drive->nice1 = 1;

                        if (hwif->ide_dma_on) {
                                /*
                                 * Force DMAing for the beginning of the check.
                                 * Some chipsets appear to do interesting
                                 * things, if not checked and cleared.
                                 *   PARANOIA!!!
                                 */
                                hwif->dma_off_quietly(drive);
                                ide_set_dma(drive);
                        }
                }
        }

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

                if (hwif->no_io_32bit)
                        drive->no_io_32bit = 1;
                else
                        drive->no_io_32bit = drive->id->dword_io ? 1 : 0;
        }
}

static int hwif_init(ide_hwif_t *hwif);
static void hwif_register_devices(ide_hwif_t *hwif);

static int probe_hwif_init(ide_hwif_t *hwif)
{
        probe_hwif(hwif);

        if (!hwif_init(hwif)) {
                printk(KERN_INFO "%s: failed to initialize IDE interface\n",
                                 hwif->name);
                return -1;
        }

        if (hwif->present)
                hwif_register_devices(hwif);

        return 0;
}

#if MAX_HWIFS > 1
/*
 * save_match() is used to simplify logic in init_irq() below.
 *
 * A loophole here is that we may not know about a particular
 * hwif's irq until after that hwif is actually probed/initialized..
 * This could be a problem for the case where an hwif is on a
 * dual interface that requires serialization (eg. cmd640) and another
 * hwif using one of the same irqs is initialized beforehand.
 *
 * This routine detects and reports such situations, but does not fix them.
 */
static void save_match(ide_hwif_t *hwif, ide_hwif_t *new, ide_hwif_t **match)
{
        ide_hwif_t *m = *match;

        if (m && m->hwgroup && m->hwgroup != new->hwgroup) {
                if (!new->hwgroup)
                        return;
                printk("%s: potential irq problem with %s and %s\n",
                        hwif->name, new->name, m->name);
        }
        if (!m || m->irq != hwif->irq) /* don't undo a prior perfect match */
                *match = new;
}
#endif /* MAX_HWIFS > 1 */

/*
 * init request queue
 */
static int ide_init_queue(ide_drive_t *drive)
{
        struct request_queue *q;
        ide_hwif_t *hwif = HWIF(drive);
        int max_sectors = 256;
        int max_sg_entries = PRD_ENTRIES;

        /*
         *      Our default set up assumes the normal IDE case,
         *      that is 64K segmenting, standard PRD setup
         *      and LBA28. Some drivers then impose their own
         *      limits and LBA48 we could raise it but as yet
         *      do not.
         */

        q = blk_init_queue_node(do_ide_request, &ide_lock, hwif_to_node(hwif));
        if (!q)
                return 1;

        q->queuedata = drive;
        blk_queue_segment_boundary(q, 0xffff);

        if (!hwif->rqsize) {
                if ((hwif->host_flags & IDE_HFLAG_NO_LBA48) ||
                    (hwif->host_flags & IDE_HFLAG_NO_LBA48_DMA))
                        hwif->rqsize = 256;
                else
                        hwif->rqsize = 65536;
        }
        if (hwif->rqsize < max_sectors)
                max_sectors = hwif->rqsize;
        blk_queue_max_sectors(q, max_sectors);

#ifdef CONFIG_PCI
        /* When we have an IOMMU, we may have a problem where pci_map_sg()
         * creates segments that don't completely match our boundary
         * requirements and thus need to be broken up again. Because it
         * doesn't align properly either, we may actually have to break up
         * to more segments than what was we got in the first place, a max
         * worst case is twice as many.
         * This will be fixed once we teach pci_map_sg() about our boundary
         * requirements, hopefully soon. *FIXME*
         */
        if (!PCI_DMA_BUS_IS_PHYS)
                max_sg_entries >>= 1;
#endif /* CONFIG_PCI */

        blk_queue_max_hw_segments(q, max_sg_entries);
        blk_queue_max_phys_segments(q, max_sg_entries);

        /* assign drive queue */
        drive->queue = q;

        /* needs drive->queue to be set */
        ide_toggle_bounce(drive, 1);

        return 0;
}

/*
 * This routine sets up the irq for an ide interface, and creates a new
 * hwgroup for the irq/hwif if none was previously assigned.
 *
 * Much of the code is for correctly detecting/handling irq sharing
 * and irq serialization situations.  This is somewhat complex because
 * it handles static as well as dynamic (PCMCIA) IDE interfaces.
 *
 * The IRQF_DISABLED 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 int index;
        ide_hwgroup_t *hwgroup;
        ide_hwif_t *match = NULL;


        BUG_ON(in_interrupt());
        BUG_ON(irqs_disabled());        
        BUG_ON(hwif == NULL);

        mutex_lock(&ide_cfg_mtx);
        hwif->hwgroup = NULL;
#if MAX_HWIFS > 1
        /*
         * Group up with any other hwifs that share our irq(s).
         */
        for (index = 0; index < MAX_HWIFS; index++) {
                ide_hwif_t *h = &ide_hwifs[index];
                if (h->hwgroup) {  /* scan only initialized hwif's */
                        if (hwif->irq == h->irq) {
                                hwif->sharing_irq = h->sharing_irq = 1;
                                if (hwif->chipset != ide_pci ||
                                    h->chipset != ide_pci) {

                                        save_match(hwif, h, &match);
                                }
                        }
                        if (hwif->serialized) {
                                if (hwif->mate && hwif->mate->irq == h->irq)
                                        save_match(hwif, h, &match);
                        }
                        if (h->serialized) {
                                if (h->mate && hwif->irq == h->mate->irq)
                                        save_match(hwif, h, &match);
                        }
                }
        }
#endif /* MAX_HWIFS > 1 */
        /*
         * If we are still without a hwgroup, then form a new one
         */
        if (match) {
                hwgroup = match->hwgroup;
                hwif->hwgroup = hwgroup;
                /*
                 * Link us into the hwgroup.
                 * This must be done early, do ensure that unexpected_intr
                 * can find the hwif and prevent irq storms.
                 * No drives are attached to the new hwif, choose_drive
                 * can't do anything stupid (yet).
                 * Add ourself as the 2nd entry to the hwgroup->hwif
                 * linked list, the first entry is the hwif that owns
                 * hwgroup->handler - do not change that.
                 */
                spin_lock_irq(&ide_lock);
                hwif->next = hwgroup->hwif->next;
                hwgroup->hwif->next = hwif;
                spin_unlock_irq(&ide_lock);
        } else {
                hwgroup = kmalloc_node(sizeof(ide_hwgroup_t),
                                        GFP_KERNEL | __GFP_ZERO,
                                        hwif_to_node(hwif->drives[0].hwif));
                if (!hwgroup)
                        goto out_up;

                hwif->hwgroup = hwgroup;

                hwgroup->hwif     = hwif->next = hwif;
                hwgroup->rq       = NULL;
                hwgroup->handler  = NULL;
                hwgroup->drive    = NULL;
                hwgroup->busy     = 0;
                init_timer(&hwgroup->timer);
                hwgroup->timer.function = &ide_timer_expiry;
                hwgroup->timer.data = (unsigned long) hwgroup;
        }

        /*
         * Allocate the irq, if not already obtained for another hwif
         */
        if (!match || match->irq != hwif->irq) {
                int sa = IRQF_DISABLED;
#if defined(__mc68000__) || defined(CONFIG_APUS)
                sa = IRQF_SHARED;
#endif /* __mc68000__ || CONFIG_APUS */

                if (IDE_CHIPSET_IS_PCI(hwif->chipset)) {
                        sa = IRQF_SHARED;
#ifndef CONFIG_IDEPCI_SHARE_IRQ
                        sa |= IRQF_DISABLED;
#endif /* CONFIG_IDEPCI_SHARE_IRQ */
                }

                if (hwif->io_ports[IDE_CONTROL_OFFSET])
                        /* clear nIEN */
                        hwif->OUTB(0x08, hwif->io_ports[IDE_CONTROL_OFFSET]);

                if (request_irq(hwif->irq,&ide_intr,sa,hwif->name,hwgroup))
                        goto out_unlink;
        }

        /*
         * For any present drive:
         * - allocate the block device queue
         * - link drive into the hwgroup
         */
        for (index = 0; index < MAX_DRIVES; ++index) {
                ide_drive_t *drive = &hwif->drives[index];
                if (!drive->present)
                        continue;
                if (ide_init_queue(drive)) {
                        printk(KERN_ERR "ide: failed to init %s\n",drive->name);
                        continue;
                }
                spin_lock_irq(&ide_lock);
                if (!hwgroup->drive) {
                        /* first drive for hwgroup. */
                        drive->next = drive;
                        hwgroup->drive = drive;
                        hwgroup->hwif = HWIF(hwgroup->drive);
                } else {
                        drive->next = hwgroup->drive->next;
                        hwgroup->drive->next = drive;
                }
                spin_unlock_irq(&ide_lock);
        }

#if !defined(__mc68000__) && !defined(CONFIG_APUS)
        printk("%s at 0x%03lx-0x%03lx,0x%03lx on irq %d", hwif->name,
                hwif->io_ports[IDE_DATA_OFFSET],
                hwif->io_ports[IDE_DATA_OFFSET]+7,
                hwif->io_ports[IDE_CONTROL_OFFSET], hwif->irq);
#else
        printk("%s at 0x%08lx on irq %d", hwif->name,
                hwif->io_ports[IDE_DATA_OFFSET], hwif->irq);
#endif /* __mc68000__ && CONFIG_APUS */
        if (match)
                printk(" (%sed with %s)",
                        hwif->sharing_irq ? "shar" : "serializ", match->name);
        printk("\n");
        mutex_unlock(&ide_cfg_mtx);
        return 0;
out_unlink:
        spin_lock_irq(&ide_lock);
        if (hwif->next == hwif) {
                BUG_ON(match);
                BUG_ON(hwgroup->hwif != hwif);
                kfree(hwgroup);
        } else {
                ide_hwif_t *g;
                g = hwgroup->hwif;
                while (g->next != hwif)
                        g = g->next;
                g->next = hwif->next;
                if (hwgroup->hwif == hwif) {
                        /* Impossible. */
                        printk(KERN_ERR "Duh. Uninitialized hwif listed as active hwif.\n");
                        hwgroup->hwif = g;
                }
                BUG_ON(hwgroup->hwif == hwif);
        }
        spin_unlock_irq(&ide_lock);
out_up:
        mutex_unlock(&ide_cfg_mtx);
        return 1;
}

static int ata_lock(dev_t dev, void *data)
{
        /* FIXME: we want to pin hwif down */
        return 0;
}

static struct kobject *ata_probe(dev_t dev, int *part, void *data)
{
        ide_hwif_t *hwif = data;
        int unit = *part >> PARTN_BITS;
        ide_drive_t *drive = &hwif->drives[unit];
        if (!drive->present)
                return NULL;

        if (drive->media == ide_disk)
                request_module("ide-disk");
        if (drive->scsi)
                request_module("ide-scsi");
        if (drive->media == ide_cdrom || drive->media == ide_optical)
                request_module("ide-cd");
        if (drive->media == ide_tape)
                request_module("ide-tape");
        if (drive->media == ide_floppy)
                request_module("ide-floppy");

        return NULL;
}

static struct kobject *exact_match(dev_t dev, int *part, void *data)
{
        struct gendisk *p = data;
        *part &= (1 << PARTN_BITS) - 1;
        return &p->kobj;
}

static int exact_lock(dev_t dev, void *data)
{
        struct gendisk *p = data;

        if (!get_disk(p))
                return -1;
        return 0;
}

void ide_register_region(struct gendisk *disk)
{
        blk_register_region(MKDEV(disk->major, disk->first_minor),
                            disk->minors, NULL, exact_match, exact_lock, disk);
}

EXPORT_SYMBOL_GPL(ide_register_region);

void ide_unregister_region(struct gendisk *disk)
{
        blk_unregister_region(MKDEV(disk->major, disk->first_minor),
                              disk->minors);
}

EXPORT_SYMBOL_GPL(ide_unregister_region);

void ide_init_disk(struct gendisk *disk, ide_drive_t *drive)
{
        ide_hwif_t *hwif = drive->hwif;
        unsigned int unit = (drive->select.all >> 4) & 1;

        disk->major = hwif->major;
        disk->first_minor = unit << PARTN_BITS;
        sprintf(disk->disk_name, "hd%c", 'a' + hwif->index * MAX_DRIVES + unit);
        disk->queue = drive->queue;
}

EXPORT_SYMBOL_GPL(ide_init_disk);

static void ide_remove_drive_from_hwgroup(ide_drive_t *drive)
{
        ide_hwgroup_t *hwgroup = drive->hwif->hwgroup;

        if (drive == drive->next) {
                /* special case: last drive from hwgroup. */
                BUG_ON(hwgroup->drive != drive);
                hwgroup->drive = NULL;
        } else {
                ide_drive_t *walk;

                walk = hwgroup->drive;
                while (walk->next != drive)
                        walk = walk->next;
                walk->next = drive->next;
                if (hwgroup->drive == drive) {
                        hwgroup->drive = drive->next;
                        hwgroup->hwif = hwgroup->drive->hwif;
                }
        }
        BUG_ON(hwgroup->drive == drive);
}

static void drive_release_dev (struct device *dev)
{
        ide_drive_t *drive = container_of(dev, ide_drive_t, gendev);

        spin_lock_irq(&ide_lock);
        ide_remove_drive_from_hwgroup(drive);
        kfree(drive->id);
        drive->id = NULL;
        drive->present = 0;
        /* Messed up locking ... */
        spin_unlock_irq(&ide_lock);
        blk_cleanup_queue(drive->queue);
        spin_lock_irq(&ide_lock);
        drive->queue = NULL;
        spin_unlock_irq(&ide_lock);

        complete(&drive->gendev_rel_comp);
}

/*
 * 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)
{
        unsigned int unit;

        for (unit = 0; unit < MAX_DRIVES; ++unit) {
                ide_drive_t * drive = &hwif->drives[unit];
                ide_add_generic_settings(drive);
                snprintf(drive->gendev.bus_id,BUS_ID_SIZE,"%u.%u",
                         hwif->index,unit);
                drive->gendev.parent = &hwif->gendev;
                drive->gendev.bus = &ide_bus_type;
                drive->gendev.driver_data = drive;
                drive->gendev.release = drive_release_dev;
        }
        blk_register_region(MKDEV(hwif->major, 0), MAX_DRIVES << PARTN_BITS,
                        THIS_MODULE, ata_probe, ata_lock, hwif);
}

static int hwif_init(ide_hwif_t *hwif)
{
        int old_irq;

        /* Return success if no device is connected */
        if (!hwif->present)
                return 1;

        if (!hwif->irq) {
                if (!(hwif->irq = ide_default_irq(hwif->io_ports[IDE_DATA_OFFSET])))
                {
                        printk("%s: DISABLED, NO IRQ\n", hwif->name);
                        return (hwif->present = 0);
                }
        }
#ifdef CONFIG_BLK_DEV_HD
        if (hwif->irq == HD_IRQ && hwif->io_ports[IDE_DATA_OFFSET] != HD_DATA) {
                printk("%s: CANNOT SHARE IRQ WITH OLD "
                        "HARDDISK DRIVER (hd.c)\n", hwif->name);
                return (hwif->present = 0);
        }
#endif /* CONFIG_BLK_DEV_HD */

        /* we set it back to 1 if all is ok below */    
        hwif->present = 0;

        if (register_blkdev(hwif->major, hwif->name))
                return 0;

        if (!hwif->sg_max_nents)
                hwif->sg_max_nents = PRD_ENTRIES;

        hwif->sg_table = kmalloc(sizeof(struct scatterlist)*hwif->sg_max_nents,
                                 GFP_KERNEL);
        if (!hwif->sg_table) {
                printk(KERN_ERR "%s: unable to allocate SG table.\n", hwif->name);
                goto out;
        }

        sg_init_table(hwif->sg_table, hwif->sg_max_nents);
        
        if (init_irq(hwif) == 0)
                goto done;

        old_irq = hwif->irq;
        /*
         *      It failed to initialise. Find the default IRQ for 
         *      this port and try that.
         */
        if (!(hwif->irq = ide_default_irq(hwif->io_ports[IDE_DATA_OFFSET]))) {
                printk("%s: Disabled unable to get IRQ %d.\n",
                        hwif->name, old_irq);
                goto out;
        }
        if (init_irq(hwif)) {
                printk("%s: probed IRQ %d and default IRQ %d failed.\n",
                        hwif->name, old_irq, hwif->irq);
                goto out;
        }
        printk("%s: probed IRQ %d failed, using default.\n",
                hwif->name, hwif->irq);

done:
        init_gendisk(hwif);

        ide_acpi_init(hwif);

        hwif->present = 1;      /* success */
        return 1;

out:
        unregister_blkdev(hwif->major, hwif->name);
        return 0;
}

static void hwif_register_devices(ide_hwif_t *hwif)
{
        unsigned int i;

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

                if (drive->present) {
                        int ret = device_register(&drive->gendev);

                        if (ret < 0)
                                printk(KERN_WARNING "IDE: %s: "
                                        "device_register error: %d\n",
                                        __FUNCTION__, ret);
                }
        }
}

int ideprobe_init (void)
{
        unsigned int index;
        int probe[MAX_HWIFS];

        memset(probe, 0, MAX_HWIFS * sizeof(int));
        for (index = 0; index < MAX_HWIFS; ++index)
                probe[index] = !ide_hwifs[index].present;

        for (index = 0; index < MAX_HWIFS; ++index)
                if (probe[index])
                        probe_hwif(&ide_hwifs[index]);
        for (index = 0; index < MAX_HWIFS; ++index)
                if (probe[index])
                        hwif_init(&ide_hwifs[index]);
        for (index = 0; index < MAX_HWIFS; ++index) {
                if (probe[index]) {
                        ide_hwif_t *hwif = &ide_hwifs[index];
                        if (!hwif->present)
                                continue;
                        if (hwif->chipset == ide_unknown || hwif->chipset == ide_forced)
                                hwif->chipset = ide_generic;
                        hwif_register_devices(hwif);
                }
        }
        for (index = 0; index < MAX_HWIFS; ++index)
                if (probe[index])
                        ide_proc_register_port(&ide_hwifs[index]);
        return 0;
}

EXPORT_SYMBOL_GPL(ideprobe_init);

int ide_device_add(u8 idx[4])
{
        int i, rc = 0;

        for (i = 0; i < 4; i++) {
                if (idx[i] != 0xff)
                        rc |= probe_hwif_init(&ide_hwifs[idx[i]]);
        }

        for (i = 0; i < 4; i++) {
                if (idx[i] != 0xff)
                        ide_proc_register_port(&ide_hwifs[idx[i]]);
        }

        return rc;
}

EXPORT_SYMBOL_GPL(ide_device_add);