Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/evalenti/linux...

[linux/fpc-iii.git] / drivers / ide / ide-probe.c

/*
 *  Copyright (C) 1994-1998   Linus Torvalds & authors (see below)
 *  Copyright (C) 2005, 2007  Bartlomiej Zolnierkiewicz
 */

/*
 *  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)
{
        u16 *id = drive->id;

        id[ATA_ID_CUR_CYLS]     = id[ATA_ID_CYLS]       = drive->cyl;
        id[ATA_ID_CUR_HEADS]    = id[ATA_ID_HEADS]      = drive->head;
        id[ATA_ID_CUR_SECTORS]  = id[ATA_ID_SECTORS]    = drive->sect;
}

static void ide_disk_init_chs(ide_drive_t *drive)
{
        u16 *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[ATA_ID_CYLS];
                drive->head = drive->bios_head = id[ATA_ID_HEADS];
                drive->sect = drive->bios_sect = id[ATA_ID_SECTORS];
        }

        /* Handle logical geometry translation by the drive */
        if (ata_id_current_chs_valid(id)) {
                drive->cyl  = id[ATA_ID_CUR_CYLS];
                drive->head = id[ATA_ID_CUR_HEADS];
                drive->sect = id[ATA_ID_CUR_SECTORS];
        }

        /* Use physical geometry if what we have still makes no sense */
        if (drive->head > 16 && id[ATA_ID_HEADS] && id[ATA_ID_HEADS] <= 16) {
                drive->cyl  = id[ATA_ID_CYLS];
                drive->head = id[ATA_ID_HEADS];
                drive->sect = id[ATA_ID_SECTORS];
        }
}

static void ide_disk_init_mult_count(ide_drive_t *drive)
{
        u16 *id = drive->id;
        u8 max_multsect = id[ATA_ID_MAX_MULTSECT] & 0xff;

        if (max_multsect) {
                if ((max_multsect / 2) > 1)
                        id[ATA_ID_MULTSECT] = max_multsect | 0x100;
                else
                        id[ATA_ID_MULTSECT] &= ~0x1ff;

                drive->mult_req = id[ATA_ID_MULTSECT] & 0xff;

                if (drive->mult_req)
                        drive->special_flags |= IDE_SFLAG_SET_MULTMODE;
        }
}

static void ide_classify_ata_dev(ide_drive_t *drive)
{
        u16 *id = drive->id;
        char *m = (char *)&id[ATA_ID_PROD];
        int is_cfa = ata_id_is_cfa(id);

        /* CF devices are *not* removable in Linux definition of the term */
        if (is_cfa == 0 && (id[ATA_ID_CONFIG] & (1 << 7)))
                drive->dev_flags |= IDE_DFLAG_REMOVABLE;

        drive->media = ide_disk;

        if (!ata_id_has_unload(drive->id))
                drive->dev_flags |= IDE_DFLAG_NO_UNLOAD;

        printk(KERN_INFO "%s: %s, %s DISK drive\n", drive->name, m,
                is_cfa ? "CFA" : "ATA");
}

static void ide_classify_atapi_dev(ide_drive_t *drive)
{
        u16 *id = drive->id;
        char *m = (char *)&id[ATA_ID_PROD];
        u8 type = (id[ATA_ID_CONFIG] >> 8) & 0x1f;

        printk(KERN_INFO "%s: %s, ATAPI ", drive->name, m);
        switch (type) {
        case ide_floppy:
                if (!strstr(m, "CD-ROM")) {
                        if (!strstr(m, "oppy") &&
                            !strstr(m, "poyp") &&
                            !strstr(m, "ZIP"))
                                printk(KERN_CONT "cdrom or floppy?, assuming ");
                        if (drive->media != ide_cdrom) {
                                printk(KERN_CONT "FLOPPY");
                                drive->dev_flags |= IDE_DFLAG_REMOVABLE;
                                break;
                        }
                }
                /* Early cdrom models used zero */
                type = ide_cdrom;
        case ide_cdrom:
                drive->dev_flags |= IDE_DFLAG_REMOVABLE;
#ifdef CONFIG_PPC
                /* kludge for Apple PowerBook internal zip */
                if (!strstr(m, "CD-ROM") && strstr(m, "ZIP")) {
                        printk(KERN_CONT "FLOPPY");
                        type = ide_floppy;
                        break;
                }
#endif
                printk(KERN_CONT "CD/DVD-ROM");
                break;
        case ide_tape:
                printk(KERN_CONT "TAPE");
                break;
        case ide_optical:
                printk(KERN_CONT "OPTICAL");
                drive->dev_flags |= IDE_DFLAG_REMOVABLE;
                break;
        default:
                printk(KERN_CONT "UNKNOWN (type %d)", type);
                break;
        }

        printk(KERN_CONT " drive\n");
        drive->media = type;
        /* an ATAPI device ignores DRDY */
        drive->ready_stat = 0;
        if (ata_id_cdb_intr(id))
                drive->atapi_flags |= IDE_AFLAG_DRQ_INTERRUPT;
        drive->dev_flags |= IDE_DFLAG_DOORLOCKING;
        /* we don't do head unloading on ATAPI devices */
        drive->dev_flags |= IDE_DFLAG_NO_UNLOAD;
}

/**
 *      do_identify     -       identify a drive
 *      @drive: drive to identify 
 *      @cmd: command used
 *      @id: buffer for IDENTIFY data
 *
 *      Called when we have issued a drive identify command to
 *      read and parse the results. This function is run with
 *      interrupts disabled. 
 */

static void do_identify(ide_drive_t *drive, u8 cmd, u16 *id)
{
        ide_hwif_t *hwif = drive->hwif;
        char *m = (char *)&id[ATA_ID_PROD];
        unsigned long flags;
        int bswap = 1;

        /* local CPU only; some systems need this */
        local_irq_save(flags);
        /* read 512 bytes of id info */
        hwif->tp_ops->input_data(drive, NULL, id, SECTOR_SIZE);
        local_irq_restore(flags);

        drive->dev_flags |= IDE_DFLAG_ID_READ;
#ifdef DEBUG
        printk(KERN_INFO "%s: dumping identify data\n", drive->name);
        ide_dump_identify((u8 *)id);
#endif
        ide_fix_driveid(id);

        /*
         *  ATA_CMD_ID_ATA returns little-endian info,
         *  ATA_CMD_ID_ATAPI *usually* returns little-endian info.
         */
        if (cmd == ATA_CMD_ID_ATAPI) {
                if ((m[0] == 'N' && m[1] == 'E') ||  /* NEC */
                    (m[0] == 'F' && m[1] == 'X') ||  /* Mitsumi */
                    (m[0] == 'P' && m[1] == 'i'))    /* Pioneer */
                        /* Vertos drives may still be weird */
                        bswap ^= 1;
        }

        ide_fixstring(m, ATA_ID_PROD_LEN, bswap);
        ide_fixstring((char *)&id[ATA_ID_FW_REV], ATA_ID_FW_REV_LEN, bswap);
        ide_fixstring((char *)&id[ATA_ID_SERNO], ATA_ID_SERNO_LEN, bswap);

        /* we depend on this a lot! */
        m[ATA_ID_PROD_LEN - 1] = '\0';

        if (strstr(m, "E X A B Y T E N E S T"))
                drive->dev_flags &= ~IDE_DFLAG_PRESENT;
        else
                drive->dev_flags |= IDE_DFLAG_PRESENT;
}

/**
 *      ide_dev_read_id -       send ATA/ATAPI IDENTIFY command
 *      @drive: drive to identify
 *      @cmd: command to use
 *      @id: buffer for IDENTIFY data
 *      @irq_ctx: flag set when called from the IRQ context
 *
 *      Sends an ATA(PI) IDENTIFY request to a drive and waits for a response.
 *
 *      Returns:        0  device was identified
 *                      1  device timed-out (no response to identify request)
 *                      2  device aborted the command (refused to identify itself)
 */

int ide_dev_read_id(ide_drive_t *drive, u8 cmd, u16 *id, int irq_ctx)
{
        ide_hwif_t *hwif = drive->hwif;
        struct ide_io_ports *io_ports = &hwif->io_ports;
        const struct ide_tp_ops *tp_ops = hwif->tp_ops;
        int use_altstatus = 0, rc;
        unsigned long timeout;
        u8 s = 0, a = 0;

        /*
         * Disable device IRQ.  Otherwise we'll get spurious interrupts
         * during the identify phase that the IRQ handler isn't expecting.
         */
        if (io_ports->ctl_addr)
                tp_ops->write_devctl(hwif, ATA_NIEN | ATA_DEVCTL_OBS);

        /* take a deep breath */
        if (irq_ctx)
                mdelay(50);
        else
                msleep(50);

        if (io_ports->ctl_addr &&
            (hwif->host_flags & IDE_HFLAG_BROKEN_ALTSTATUS) == 0) {
                a = tp_ops->read_altstatus(hwif);
                s = tp_ops->read_status(hwif);
                if ((a ^ s) & ~ATA_SENSE)
                        /* ancient Seagate drives, broken interfaces */
                        printk(KERN_INFO "%s: probing with STATUS(0x%02x) "
                                         "instead of ALTSTATUS(0x%02x)\n",
                                         drive->name, s, a);
                else
                        /* use non-intrusive polling */
                        use_altstatus = 1;
        }

        /* set features register for atapi
         * identify command to be sure of reply
         */
        if (cmd == ATA_CMD_ID_ATAPI) {
                struct ide_taskfile tf;

                memset(&tf, 0, sizeof(tf));
                /* disable DMA & overlap */
                tp_ops->tf_load(drive, &tf, IDE_VALID_FEATURE);
        }

        /* ask drive for ID */
        tp_ops->exec_command(hwif, cmd);

        timeout = ((cmd == ATA_CMD_ID_ATA) ? WAIT_WORSTCASE : WAIT_PIDENTIFY) / 2;

        /* wait for IRQ and ATA_DRQ */
        if (irq_ctx) {
                rc = __ide_wait_stat(drive, ATA_DRQ, BAD_R_STAT, timeout, &s);
                if (rc)
                        return 1;
        } else {
                rc = ide_busy_sleep(drive, timeout, use_altstatus);
                if (rc)
                        return 1;

                msleep(50);
                s = tp_ops->read_status(hwif);
        }

        if (OK_STAT(s, ATA_DRQ, BAD_R_STAT)) {
                /* drive returned ID */
                do_identify(drive, cmd, id);
                /* drive responded with ID */
                rc = 0;
                /* clear drive IRQ */
                (void)tp_ops->read_status(hwif);
        } else {
                /* drive refused ID */
                rc = 2;
        }
        return rc;
}

int ide_busy_sleep(ide_drive_t *drive, unsigned long timeout, int altstatus)
{
        ide_hwif_t *hwif = drive->hwif;
        u8 stat;

        timeout += jiffies;

        do {
                msleep(50);     /* give drive a breather */
                stat = altstatus ? hwif->tp_ops->read_altstatus(hwif)
                                 : hwif->tp_ops->read_status(hwif);
                if ((stat & ATA_BUSY) == 0)
                        return 0;
        } while (time_before(jiffies, timeout));

        printk(KERN_ERR "%s: timeout in %s\n", drive->name, __func__);

        return 1;       /* drive timed-out */
}

static u8 ide_read_device(ide_drive_t *drive)
{
        struct ide_taskfile tf;

        drive->hwif->tp_ops->tf_read(drive, &tf, IDE_VALID_DEVICE);

        return tf.device;
}

/**
 *      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)
{
        ide_hwif_t *hwif = drive->hwif;
        const struct ide_tp_ops *tp_ops = hwif->tp_ops;
        u16 *id = drive->id;
        int rc;
        u8 present = !!(drive->dev_flags & IDE_DFLAG_PRESENT), stat;

        /* avoid waiting for inappropriate probes */
        if (present && drive->media != ide_disk && cmd == ATA_CMD_ID_ATA)
                return 4;

#ifdef DEBUG
        printk(KERN_INFO "probing for %s: present=%d, media=%d, probetype=%s\n",
                drive->name, present, drive->media,
                (cmd == ATA_CMD_ID_ATA) ? "ATA" : "ATAPI");
#endif

        /* needed for some systems
         * (e.g. crw9624 as drive0 with disk as slave)
         */
        msleep(50);
        tp_ops->dev_select(drive);
        msleep(50);

        if (ide_read_device(drive) != drive->select && present == 0) {
                if (drive->dn & 1) {
                        /* exit with drive0 selected */
                        tp_ops->dev_select(hwif->devices[0]);
                        /* allow ATA_BUSY to assert & clear */
                        msleep(50);
                }
                /* no i/f present: mmm.. this should be a 4 -ml */
                return 3;
        }

        stat = tp_ops->read_status(hwif);

        if (OK_STAT(stat, ATA_DRDY, ATA_BUSY) ||
            present || cmd == ATA_CMD_ID_ATAPI) {
                rc = ide_dev_read_id(drive, cmd, id, 0);
                if (rc)
                        /* failed: try again */
                        rc = ide_dev_read_id(drive, cmd, id, 0);

                stat = tp_ops->read_status(hwif);

                if (stat == (ATA_BUSY | ATA_DRDY))
                        return 4;

                if (rc == 1 && cmd == ATA_CMD_ID_ATAPI) {
                        printk(KERN_ERR "%s: no response (status = 0x%02x), "
                                        "resetting drive\n", drive->name, stat);
                        msleep(50);
                        tp_ops->dev_select(drive);
                        msleep(50);
                        tp_ops->exec_command(hwif, ATA_CMD_DEV_RESET);
                        (void)ide_busy_sleep(drive, WAIT_WORSTCASE, 0);
                        rc = ide_dev_read_id(drive, cmd, id, 0);
                }

                /* ensure drive IRQ is clear */
                stat = tp_ops->read_status(hwif);

                if (rc == 1)
                        printk(KERN_ERR "%s: no response (status = 0x%02x)\n",
                                        drive->name, stat);
        } else {
                /* not present or maybe ATAPI */
                rc = 3;
        }
        if (drive->dn & 1) {
                /* exit with drive0 selected */
                tp_ops->dev_select(hwif->devices[0]);
                msleep(50);
                /* ensure drive irq is clear */
                (void)tp_ops->read_status(hwif);
        }
        return rc;
}

/**
 *      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: IDE_DFLAG_PRESENT might still be not set)
 */

static u8 probe_for_drive(ide_drive_t *drive)
{
        char *m;
        int rc;
        u8 cmd;

        drive->dev_flags &= ~IDE_DFLAG_ID_READ;

        m = (char *)&drive->id[ATA_ID_PROD];
        strcpy(m, "UNKNOWN");

        /* skip probing? */
        if ((drive->dev_flags & IDE_DFLAG_NOPROBE) == 0) {
                /* if !(success||timed-out) */
                cmd = ATA_CMD_ID_ATA;
                rc = do_probe(drive, cmd);
                if (rc >= 2) {
                        /* look for ATAPI device */
                        cmd = ATA_CMD_ID_ATAPI;
                        rc = do_probe(drive, cmd);
                }

                if ((drive->dev_flags & IDE_DFLAG_PRESENT) == 0)
                        return 0;

                /* identification failed? */
                if ((drive->dev_flags & IDE_DFLAG_ID_READ) == 0) {
                        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->dev_flags &= ~IDE_DFLAG_PRESENT;
                        }
                } else {
                        if (cmd == ATA_CMD_ID_ATAPI)
                                ide_classify_atapi_dev(drive);
                        else
                                ide_classify_ata_dev(drive);
                }
        }

        if ((drive->dev_flags & IDE_DFLAG_PRESENT) == 0)
                return 0;

        /* The drive wasn't being helpful. Add generic info only */
        if ((drive->dev_flags & IDE_DFLAG_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 1;
}

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 int ide_register_port(ide_hwif_t *hwif)
{
        int ret;

        /* register with global device tree */
        dev_set_name(&hwif->gendev, "%s", hwif->name);
        dev_set_drvdata(&hwif->gendev, hwif);
        if (hwif->gendev.parent == NULL)
                hwif->gendev.parent = hwif->dev;
        hwif->gendev.release = hwif_release_dev;

        ret = device_register(&hwif->gendev);
        if (ret < 0) {
                printk(KERN_WARNING "IDE: %s: device_register error: %d\n",
                        __func__, ret);
                goto out;
        }

        hwif->portdev = device_create(ide_port_class, &hwif->gendev,
                                      MKDEV(0, 0), hwif, "%s", hwif->name);
        if (IS_ERR(hwif->portdev)) {
                ret = PTR_ERR(hwif->portdev);
                device_unregister(&hwif->gendev);
        }
out:
        return ret;
}

/**
 *      ide_port_wait_ready     -       wait for port to become ready
 *      @hwif: IDE port
 *
 *      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-non-busy should not harm any existing
 *      configuration and fix some issues like the above.
 *
 *      BenH.
 *
 *      Returns 0 on success, error code (< 0) otherwise.
 */

static int ide_port_wait_ready(ide_hwif_t *hwif)
{
        const struct ide_tp_ops *tp_ops = hwif->tp_ops;
        ide_drive_t *drive;
        int i, 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 */
        ide_port_for_each_dev(i, drive, hwif) {
                /* Ignore disks that we will not probe for later. */
                if ((drive->dev_flags & IDE_DFLAG_NOPROBE) == 0 ||
                    (drive->dev_flags & IDE_DFLAG_PRESENT)) {
                        tp_ops->dev_select(drive);
                        tp_ops->write_devctl(hwif, ATA_DEVCTL_OBS);
                        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 (i)
                tp_ops->dev_select(hwif->devices[0]);

        return rc;
}

/**
 *      ide_undecoded_slave     -       look for bad CF adapters
 *      @dev1: slave device
 *
 *      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_drive_t *dev1)
{
        ide_drive_t *dev0 = dev1->hwif->devices[0];

        if ((dev1->dn & 1) == 0 || (dev0->dev_flags & IDE_DFLAG_PRESENT) == 0)
                return;

        /* If the models don't match they are not the same product */
        if (strcmp((char *)&dev0->id[ATA_ID_PROD],
                   (char *)&dev1->id[ATA_ID_PROD]))
                return;

        /* Serial numbers do not match */
        if (strncmp((char *)&dev0->id[ATA_ID_SERNO],
                    (char *)&dev1->id[ATA_ID_SERNO], ATA_ID_SERNO_LEN))
                return;

        /* No serial number, thankfully very rare for CF */
        if (*(char *)&dev0->id[ATA_ID_SERNO] == 0)
                return;

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

        dev1->dev_flags &= ~IDE_DFLAG_PRESENT;
}

EXPORT_SYMBOL_GPL(ide_undecoded_slave);

static int ide_probe_port(ide_hwif_t *hwif)
{
        ide_drive_t *drive;
        unsigned int irqd;
        int i, rc = -ENODEV;

        BUG_ON(hwif->present);

        if ((hwif->devices[0]->dev_flags & IDE_DFLAG_NOPROBE) &&
            (hwif->devices[1]->dev_flags & IDE_DFLAG_NOPROBE))
                return -EACCES;

        /*
         * 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);

        if (ide_port_wait_ready(hwif) == -EBUSY)
                printk(KERN_DEBUG "%s: Wait for ready failed before probe !\n", hwif->name);

        /*
         * Second drive should only exist if first drive was found,
         * but a lot of cdrom drives are configured as single slaves.
         */
        ide_port_for_each_dev(i, drive, hwif) {
                (void) probe_for_drive(drive);
                if (drive->dev_flags & IDE_DFLAG_PRESENT)
                        rc = 0;
        }

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

        return rc;
}

static void ide_port_tune_devices(ide_hwif_t *hwif)
{
        const struct ide_port_ops *port_ops = hwif->port_ops;
        ide_drive_t *drive;
        int i;

        ide_port_for_each_present_dev(i, drive, hwif) {
                ide_check_nien_quirk_list(drive);

                if (port_ops && port_ops->quirkproc)
                        port_ops->quirkproc(drive);
        }

        ide_port_for_each_present_dev(i, drive, hwif) {
                ide_set_max_pio(drive);

                drive->dev_flags |= IDE_DFLAG_NICE1;

                if (hwif->dma_ops)
                        ide_set_dma(drive);
        }
}

/*
 * init request queue
 */
static int ide_init_queue(ide_drive_t *drive)
{
        struct request_queue *q;
        ide_hwif_t *hwif = drive->hwif;
        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, NULL, hwif_to_node(hwif));
        if (!q)
                return 1;

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

        if (hwif->rqsize < max_sectors)
                max_sectors = hwif->rqsize;
        blk_queue_max_hw_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_segments(q, max_sg_entries);

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

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

        return 0;
}

static DEFINE_MUTEX(ide_cfg_mtx);

/*
 * For any present drive:
 * - allocate the block device queue
 */
static int ide_port_setup_devices(ide_hwif_t *hwif)
{
        ide_drive_t *drive;
        int i, j = 0;

        mutex_lock(&ide_cfg_mtx);
        ide_port_for_each_present_dev(i, drive, hwif) {
                if (ide_init_queue(drive)) {
                        printk(KERN_ERR "ide: failed to init %s\n",
                                        drive->name);
                        drive->dev_flags &= ~IDE_DFLAG_PRESENT;
                        continue;
                }

                j++;
        }
        mutex_unlock(&ide_cfg_mtx);

        return j;
}

static void ide_host_enable_irqs(struct ide_host *host)
{
        ide_hwif_t *hwif;
        int i;

        ide_host_for_each_port(i, hwif, host) {
                if (hwif == NULL)
                        continue;

                /* clear any pending IRQs */
                hwif->tp_ops->read_status(hwif);

                /* unmask IRQs */
                if (hwif->io_ports.ctl_addr)
                        hwif->tp_ops->write_devctl(hwif, ATA_DEVCTL_OBS);
        }
}

/*
 * This routine sets up the IRQ for an IDE interface.
 */
static int init_irq (ide_hwif_t *hwif)
{
        struct ide_io_ports *io_ports = &hwif->io_ports;
        struct ide_host *host = hwif->host;
        irq_handler_t irq_handler = host->irq_handler;
        int sa = host->irq_flags;

        if (irq_handler == NULL)
                irq_handler = ide_intr;

        if (!host->get_lock)
                if (request_irq(hwif->irq, irq_handler, sa, hwif->name, hwif))
                        goto out_up;

#if !defined(__mc68000__)
        printk(KERN_INFO "%s at 0x%03lx-0x%03lx,0x%03lx on irq %d", hwif->name,
                io_ports->data_addr, io_ports->status_addr,
                io_ports->ctl_addr, hwif->irq);
#else
        printk(KERN_INFO "%s at 0x%08lx on irq %d", hwif->name,
                io_ports->data_addr, hwif->irq);
#endif /* __mc68000__ */
        if (hwif->host->host_flags & IDE_HFLAG_SERIALIZE)
                printk(KERN_CONT " (serialized)");
        printk(KERN_CONT "\n");

        return 0;
out_up:
        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->devices[unit];

        if ((drive->dev_flags & IDE_DFLAG_PRESENT) == 0)
                return NULL;

        if (drive->media == ide_disk)
                request_module("ide-disk");
        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 &disk_to_dev(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->dn & 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 drive_release_dev (struct device *dev)
{
        ide_drive_t *drive = container_of(dev, ide_drive_t, gendev);

        ide_proc_unregister_device(drive);

        blk_cleanup_queue(drive->queue);
        drive->queue = NULL;

        drive->dev_flags &= ~IDE_DFLAG_PRESENT;

        complete(&drive->gendev_rel_comp);
}

static int hwif_init(ide_hwif_t *hwif)
{
        if (!hwif->irq) {
                printk(KERN_ERR "%s: disabled, no IRQ\n", hwif->name);
                return 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)) {
                printk(KERN_ERR "%s: disabled, unable to get IRQ %d\n",
                        hwif->name, hwif->irq);
                goto out;
        }

        blk_register_region(MKDEV(hwif->major, 0), MAX_DRIVES << PARTN_BITS,
                            THIS_MODULE, ata_probe, ata_lock, hwif);
        return 1;

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

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

        ide_port_for_each_present_dev(i, drive, hwif) {
                struct device *dev = &drive->gendev;
                int ret;

                dev_set_name(dev, "%u.%u", hwif->index, i);
                dev_set_drvdata(dev, drive);
                dev->parent = &hwif->gendev;
                dev->bus = &ide_bus_type;
                dev->release = drive_release_dev;

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

static void ide_port_init_devices(ide_hwif_t *hwif)
{
        const struct ide_port_ops *port_ops = hwif->port_ops;
        ide_drive_t *drive;
        int i;

        ide_port_for_each_dev(i, drive, hwif) {
                drive->dn = i + hwif->channel * 2;

                if (hwif->host_flags & IDE_HFLAG_IO_32BIT)
                        drive->io_32bit = 1;
                if (hwif->host_flags & IDE_HFLAG_NO_IO_32BIT)
                        drive->dev_flags |= IDE_DFLAG_NO_IO_32BIT;
                if (hwif->host_flags & IDE_HFLAG_UNMASK_IRQS)
                        drive->dev_flags |= IDE_DFLAG_UNMASK;
                if (hwif->host_flags & IDE_HFLAG_NO_UNMASK_IRQS)
                        drive->dev_flags |= IDE_DFLAG_NO_UNMASK;

                drive->pio_mode = XFER_PIO_0;

                if (port_ops && port_ops->init_dev)
                        port_ops->init_dev(drive);
        }
}

static void ide_init_port(ide_hwif_t *hwif, unsigned int port,
                          const struct ide_port_info *d)
{
        hwif->channel = port;

        hwif->chipset = d->chipset ? d->chipset : ide_pci;

        if (d->init_iops)
                d->init_iops(hwif);

        /* ->host_flags may be set by ->init_iops (or even earlier...) */
        hwif->host_flags |= d->host_flags;
        hwif->pio_mask = d->pio_mask;

        if (d->tp_ops)
                hwif->tp_ops = d->tp_ops;

        /* ->set_pio_mode for DTC2278 is currently limited to port 0 */
        if ((hwif->host_flags & IDE_HFLAG_DTC2278) == 0 || hwif->channel == 0)
                hwif->port_ops = d->port_ops;

        hwif->swdma_mask = d->swdma_mask;
        hwif->mwdma_mask = d->mwdma_mask;
        hwif->ultra_mask = d->udma_mask;

        if ((d->host_flags & IDE_HFLAG_NO_DMA) == 0) {
                int rc;

                hwif->dma_ops = d->dma_ops;

                if (d->init_dma)
                        rc = d->init_dma(hwif, d);
                else
                        rc = ide_hwif_setup_dma(hwif, d);

                if (rc < 0) {
                        printk(KERN_INFO "%s: DMA disabled\n", hwif->name);

                        hwif->dma_ops = NULL;
                        hwif->dma_base = 0;
                        hwif->swdma_mask = 0;
                        hwif->mwdma_mask = 0;
                        hwif->ultra_mask = 0;
                }
        }

        if ((d->host_flags & IDE_HFLAG_SERIALIZE) ||
            ((d->host_flags & IDE_HFLAG_SERIALIZE_DMA) && hwif->dma_base))
                hwif->host->host_flags |= IDE_HFLAG_SERIALIZE;

        if (d->max_sectors)
                hwif->rqsize = d->max_sectors;
        else {
                if ((hwif->host_flags & IDE_HFLAG_NO_LBA48) ||
                    (hwif->host_flags & IDE_HFLAG_NO_LBA48_DMA))
                        hwif->rqsize = 256;
                else
                        hwif->rqsize = 65536;
        }

        /* call chipset specific routine for each enabled port */
        if (d->init_hwif)
                d->init_hwif(hwif);
}

static void ide_port_cable_detect(ide_hwif_t *hwif)
{
        const struct ide_port_ops *port_ops = hwif->port_ops;

        if (port_ops && port_ops->cable_detect && (hwif->ultra_mask & 0x78)) {
                if (hwif->cbl != ATA_CBL_PATA40_SHORT)
                        hwif->cbl = port_ops->cable_detect(hwif);
        }
}

static const u8 ide_hwif_to_major[] =
        { IDE0_MAJOR, IDE1_MAJOR, IDE2_MAJOR, IDE3_MAJOR, IDE4_MAJOR,
          IDE5_MAJOR, IDE6_MAJOR, IDE7_MAJOR, IDE8_MAJOR, IDE9_MAJOR };

static void ide_port_init_devices_data(ide_hwif_t *hwif)
{
        ide_drive_t *drive;
        int i;

        ide_port_for_each_dev(i, drive, hwif) {
                u8 j = (hwif->index * MAX_DRIVES) + i;
                u16 *saved_id = drive->id;

                memset(drive, 0, sizeof(*drive));
                memset(saved_id, 0, SECTOR_SIZE);
                drive->id = saved_id;

                drive->media                    = ide_disk;
                drive->select                   = (i << 4) | ATA_DEVICE_OBS;
                drive->hwif                     = hwif;
                drive->ready_stat               = ATA_DRDY;
                drive->bad_wstat                = BAD_W_STAT;
                drive->special_flags            = IDE_SFLAG_RECALIBRATE |
                                                  IDE_SFLAG_SET_GEOMETRY;
                drive->name[0]                  = 'h';
                drive->name[1]                  = 'd';
                drive->name[2]                  = 'a' + j;
                drive->max_failures             = IDE_DEFAULT_MAX_FAILURES;

                INIT_LIST_HEAD(&drive->list);
                init_completion(&drive->gendev_rel_comp);
        }
}

static void ide_init_port_data(ide_hwif_t *hwif, unsigned int index)
{
        /* fill in any non-zero initial values */
        hwif->index     = index;
        hwif->major     = ide_hwif_to_major[index];

        hwif->name[0]   = 'i';
        hwif->name[1]   = 'd';
        hwif->name[2]   = 'e';
        hwif->name[3]   = '0' + index;

        spin_lock_init(&hwif->lock);

        init_timer(&hwif->timer);
        hwif->timer.function = &ide_timer_expiry;
        hwif->timer.data = (unsigned long)hwif;

        init_completion(&hwif->gendev_rel_comp);

        hwif->tp_ops = &default_tp_ops;

        ide_port_init_devices_data(hwif);
}

static void ide_init_port_hw(ide_hwif_t *hwif, struct ide_hw *hw)
{
        memcpy(&hwif->io_ports, &hw->io_ports, sizeof(hwif->io_ports));
        hwif->irq = hw->irq;
        hwif->dev = hw->dev;
        hwif->gendev.parent = hw->parent ? hw->parent : hw->dev;
        hwif->config_data = hw->config;
}

static unsigned int ide_indexes;

/**
 *      ide_find_port_slot      -       find free port slot
 *      @d: IDE port info
 *
 *      Return the new port slot index or -ENOENT if we are out of free slots.
 */

static int ide_find_port_slot(const struct ide_port_info *d)
{
        int idx = -ENOENT;
        u8 bootable = (d && (d->host_flags & IDE_HFLAG_NON_BOOTABLE)) ? 0 : 1;
        u8 i = (d && (d->host_flags & IDE_HFLAG_QD_2ND_PORT)) ? 1 : 0;

        /*
         * Claim an unassigned slot.
         *
         * Give preference to claiming other slots before claiming ide0/ide1,
         * just in case there's another interface yet-to-be-scanned
         * which uses ports 0x1f0/0x170 (the ide0/ide1 defaults).
         *
         * Unless there is a bootable card that does not use the standard
         * ports 0x1f0/0x170 (the ide0/ide1 defaults).
         */
        mutex_lock(&ide_cfg_mtx);
        if (bootable) {
                if ((ide_indexes | i) != (1 << MAX_HWIFS) - 1)
                        idx = ffz(ide_indexes | i);
        } else {
                if ((ide_indexes | 3) != (1 << MAX_HWIFS) - 1)
                        idx = ffz(ide_indexes | 3);
                else if ((ide_indexes & 3) != 3)
                        idx = ffz(ide_indexes);
        }
        if (idx >= 0)
                ide_indexes |= (1 << idx);
        mutex_unlock(&ide_cfg_mtx);

        return idx;
}

static void ide_free_port_slot(int idx)
{
        mutex_lock(&ide_cfg_mtx);
        ide_indexes &= ~(1 << idx);
        mutex_unlock(&ide_cfg_mtx);
}

static void ide_port_free_devices(ide_hwif_t *hwif)
{
        ide_drive_t *drive;
        int i;

        ide_port_for_each_dev(i, drive, hwif) {
                kfree(drive->id);
                kfree(drive);
        }
}

static int ide_port_alloc_devices(ide_hwif_t *hwif, int node)
{
        int i;

        for (i = 0; i < MAX_DRIVES; i++) {
                ide_drive_t *drive;

                drive = kzalloc_node(sizeof(*drive), GFP_KERNEL, node);
                if (drive == NULL)
                        goto out_nomem;

                /*
                 * 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_node(SECTOR_SIZE, GFP_KERNEL, node);
                if (drive->id == NULL)
                        goto out_nomem;

                hwif->devices[i] = drive;
        }
        return 0;

out_nomem:
        ide_port_free_devices(hwif);
        return -ENOMEM;
}

struct ide_host *ide_host_alloc(const struct ide_port_info *d,
                                struct ide_hw **hws, unsigned int n_ports)
{
        struct ide_host *host;
        struct device *dev = hws[0] ? hws[0]->dev : NULL;
        int node = dev ? dev_to_node(dev) : -1;
        int i;

        host = kzalloc_node(sizeof(*host), GFP_KERNEL, node);
        if (host == NULL)
                return NULL;

        for (i = 0; i < n_ports; i++) {
                ide_hwif_t *hwif;
                int idx;

                if (hws[i] == NULL)
                        continue;

                hwif = kzalloc_node(sizeof(*hwif), GFP_KERNEL, node);
                if (hwif == NULL)
                        continue;

                if (ide_port_alloc_devices(hwif, node) < 0) {
                        kfree(hwif);
                        continue;
                }

                idx = ide_find_port_slot(d);
                if (idx < 0) {
                        printk(KERN_ERR "%s: no free slot for interface\n",
                                        d ? d->name : "ide");
                        ide_port_free_devices(hwif);
                        kfree(hwif);
                        continue;
                }

                ide_init_port_data(hwif, idx);

                hwif->host = host;

                host->ports[i] = hwif;
                host->n_ports++;
        }

        if (host->n_ports == 0) {
                kfree(host);
                return NULL;
        }

        host->dev[0] = dev;

        if (d) {
                host->init_chipset = d->init_chipset;
                host->get_lock     = d->get_lock;
                host->release_lock = d->release_lock;
                host->host_flags = d->host_flags;
                host->irq_flags = d->irq_flags;
        }

        return host;
}
EXPORT_SYMBOL_GPL(ide_host_alloc);

static void ide_port_free(ide_hwif_t *hwif)
{
        ide_port_free_devices(hwif);
        ide_free_port_slot(hwif->index);
        kfree(hwif);
}

static void ide_disable_port(ide_hwif_t *hwif)
{
        struct ide_host *host = hwif->host;
        int i;

        printk(KERN_INFO "%s: disabling port\n", hwif->name);

        for (i = 0; i < MAX_HOST_PORTS; i++) {
                if (host->ports[i] == hwif) {
                        host->ports[i] = NULL;
                        host->n_ports--;
                }
        }

        ide_port_free(hwif);
}

int ide_host_register(struct ide_host *host, const struct ide_port_info *d,
                      struct ide_hw **hws)
{
        ide_hwif_t *hwif, *mate = NULL;
        int i, j = 0;

        ide_host_for_each_port(i, hwif, host) {
                if (hwif == NULL) {
                        mate = NULL;
                        continue;
                }

                ide_init_port_hw(hwif, hws[i]);
                ide_port_apply_params(hwif);

                if ((i & 1) && mate) {
                        hwif->mate = mate;
                        mate->mate = hwif;
                }

                mate = (i & 1) ? NULL : hwif;

                ide_init_port(hwif, i & 1, d);
                ide_port_cable_detect(hwif);

                hwif->port_flags |= IDE_PFLAG_PROBING;

                ide_port_init_devices(hwif);
        }

        ide_host_for_each_port(i, hwif, host) {
                if (hwif == NULL)
                        continue;

                if (ide_probe_port(hwif) == 0)
                        hwif->present = 1;

                hwif->port_flags &= ~IDE_PFLAG_PROBING;

                if ((hwif->host_flags & IDE_HFLAG_4DRIVES) == 0 ||
                    hwif->mate == NULL || hwif->mate->present == 0) {
                        if (ide_register_port(hwif)) {
                                ide_disable_port(hwif);
                                continue;
                        }
                }

                if (hwif->present)
                        ide_port_tune_devices(hwif);
        }

        ide_host_enable_irqs(host);

        ide_host_for_each_port(i, hwif, host) {
                if (hwif == NULL)
                        continue;

                if (hwif_init(hwif) == 0) {
                        printk(KERN_INFO "%s: failed to initialize IDE "
                                         "interface\n", hwif->name);
                        device_unregister(&hwif->gendev);
                        ide_disable_port(hwif);
                        continue;
                }

                if (hwif->present)
                        if (ide_port_setup_devices(hwif) == 0) {
                                hwif->present = 0;
                                continue;
                        }

                j++;

                ide_acpi_init_port(hwif);

                if (hwif->present)
                        ide_acpi_port_init_devices(hwif);
        }

        ide_host_for_each_port(i, hwif, host) {
                if (hwif == NULL)
                        continue;

                ide_sysfs_register_port(hwif);
                ide_proc_register_port(hwif);

                if (hwif->present) {
                        ide_proc_port_register_devices(hwif);
                        hwif_register_devices(hwif);
                }
        }

        return j ? 0 : -1;
}
EXPORT_SYMBOL_GPL(ide_host_register);

int ide_host_add(const struct ide_port_info *d, struct ide_hw **hws,
                 unsigned int n_ports, struct ide_host **hostp)
{
        struct ide_host *host;
        int rc;

        host = ide_host_alloc(d, hws, n_ports);
        if (host == NULL)
                return -ENOMEM;

        rc = ide_host_register(host, d, hws);
        if (rc) {
                ide_host_free(host);
                return rc;
        }

        if (hostp)
                *hostp = host;

        return 0;
}
EXPORT_SYMBOL_GPL(ide_host_add);

static void __ide_port_unregister_devices(ide_hwif_t *hwif)
{
        ide_drive_t *drive;
        int i;

        ide_port_for_each_present_dev(i, drive, hwif) {
                device_unregister(&drive->gendev);
                wait_for_completion(&drive->gendev_rel_comp);
        }
}

void ide_port_unregister_devices(ide_hwif_t *hwif)
{
        mutex_lock(&ide_cfg_mtx);
        __ide_port_unregister_devices(hwif);
        hwif->present = 0;
        ide_port_init_devices_data(hwif);
        mutex_unlock(&ide_cfg_mtx);
}
EXPORT_SYMBOL_GPL(ide_port_unregister_devices);

/**
 *      ide_unregister          -       free an IDE interface
 *      @hwif: IDE interface
 *
 *      Perform the final unregister of an IDE interface.
 *
 *      Locking:
 *      The caller must not hold the IDE locks.
 *
 *      It is up to the caller to be sure there is no pending I/O here,
 *      and that the interface will not be reopened (present/vanishing
 *      locking isn't yet done BTW).
 */

static void ide_unregister(ide_hwif_t *hwif)
{
        BUG_ON(in_interrupt());
        BUG_ON(irqs_disabled());

        mutex_lock(&ide_cfg_mtx);

        if (hwif->present) {
                __ide_port_unregister_devices(hwif);
                hwif->present = 0;
        }

        ide_proc_unregister_port(hwif);

        if (!hwif->host->get_lock)
                free_irq(hwif->irq, hwif);

        device_unregister(hwif->portdev);
        device_unregister(&hwif->gendev);
        wait_for_completion(&hwif->gendev_rel_comp);

        /*
         * Remove us from the kernel's knowledge
         */
        blk_unregister_region(MKDEV(hwif->major, 0), MAX_DRIVES<<PARTN_BITS);
        kfree(hwif->sg_table);
        unregister_blkdev(hwif->major, hwif->name);

        ide_release_dma_engine(hwif);

        mutex_unlock(&ide_cfg_mtx);
}

void ide_host_free(struct ide_host *host)
{
        ide_hwif_t *hwif;
        int i;

        ide_host_for_each_port(i, hwif, host) {
                if (hwif)
                        ide_port_free(hwif);
        }

        kfree(host);
}
EXPORT_SYMBOL_GPL(ide_host_free);

void ide_host_remove(struct ide_host *host)
{
        ide_hwif_t *hwif;
        int i;

        ide_host_for_each_port(i, hwif, host) {
                if (hwif)
                        ide_unregister(hwif);
        }

        ide_host_free(host);
}
EXPORT_SYMBOL_GPL(ide_host_remove);

void ide_port_scan(ide_hwif_t *hwif)
{
        int rc;

        ide_port_apply_params(hwif);
        ide_port_cable_detect(hwif);

        hwif->port_flags |= IDE_PFLAG_PROBING;

        ide_port_init_devices(hwif);

        rc = ide_probe_port(hwif);

        hwif->port_flags &= ~IDE_PFLAG_PROBING;

        if (rc < 0)
                return;

        hwif->present = 1;

        ide_port_tune_devices(hwif);
        ide_port_setup_devices(hwif);
        ide_acpi_port_init_devices(hwif);
        hwif_register_devices(hwif);
        ide_proc_port_register_devices(hwif);
}
EXPORT_SYMBOL_GPL(ide_port_scan);