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.b.set_multmode = 1;
	}
}

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

	/* 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"))
		goto err_misc;

	printk(KERN_INFO "%s: %s, ", drive->name, m);

	drive->dev_flags |= IDE_DFLAG_PRESENT;
	drive->dev_flags &= ~IDE_DFLAG_DEAD;

	/*
	 * Check for an ATAPI device
	 */
	if (cmd == ATA_CMD_ID_ATAPI) {
		u8 type = (id[ATA_ID_CONFIG] >> 8) & 0x1f;

		printk(KERN_CONT "ATAPI ");
		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;
		return;
	}

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

	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_CONT "%s DISK drive\n", is_cfa ? "CFA" : "ATA");

	return;

err_misc:
	kfree(id);
	drive->dev_flags &= ~IDE_DFLAG_PRESENT;
	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);
	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;

	/* take a deep breath */
	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_IDX)
			/* 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) {
		ide_task_t task;

		memset(&task, 0, sizeof(task));
		/* disable DMA & overlap */
		task.tf_flags = IDE_TFLAG_OUT_FEATURE;

		tp_ops->tf_load(drive, &task);
	}

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

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

	if (ide_busy_sleep(hwif, timeout, use_altstatus))
		return 1;

	/* wait for IRQ and ATA_DRQ */
	msleep(50);
	s = tp_ops->read_status(hwif);

	if (OK_STAT(s, ATA_DRQ, BAD_R_STAT)) {
		/* drive returned ID */
		do_identify(drive, cmd);
		/* drive responded with ID */
		rc = 0;
		/* clear drive IRQ */
		(void)tp_ops->read_status(hwif);
	} 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);
	const struct ide_tp_ops *tp_ops = hwif->tp_ops;
	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 (hwif->io_ports.ctl_addr) {
		if (!hwif->irq) {
			autoprobe = 1;
			cookie = probe_irq_on();
		}
		tp_ops->set_irq(hwif, autoprobe);
	}

	retval = actual_try_to_identify(drive, cmd);

	if (autoprobe) {
		int irq;

		tp_ops->set_irq(hwif, 0);
		/* clear drive IRQ */
		(void)tp_ops->read_status(hwif);
		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(KERN_ERR "%s: IRQ probe failed (0x%lx)\n",
					drive->name, cookie);
			}
		}
	}
	return retval;
}

int ide_busy_sleep(ide_hwif_t *hwif, unsigned long timeout, int altstatus)
{
	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));

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

static u8 ide_read_device(ide_drive_t *drive)
{
	ide_task_t task;

	memset(&task, 0, sizeof(task));
	task.tf_flags = IDE_TFLAG_IN_DEVICE;

	drive->hwif->tp_ops->tf_read(drive, &task);

	return task.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 = HWIF(drive);
	const struct ide_tp_ops *tp_ops = hwif->tp_ops;
	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);
	SELECT_DRIVE(drive);
	msleep(50);

	if (ide_read_device(drive) != drive->select && present == 0) {
		if (drive->dn & 1) {
			/* exit with drive0 selected */
			SELECT_DRIVE(&hwif->drives[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) {
		/* send cmd and wait */
		if ((rc = try_to_identify(drive, cmd))) {
			/* failed: try again */
			rc = try_to_identify(drive,cmd);
		}

		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);
			SELECT_DRIVE(drive);
			msleep(50);
			tp_ops->exec_command(hwif, ATA_CMD_DEV_RESET);
			(void)ide_busy_sleep(hwif, WAIT_WORSTCASE, 0);
			rc = try_to_identify(drive, cmd);
		}

		/* 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 */
		SELECT_DRIVE(&hwif->drives[0]);
		msleep(50);
		/* ensure drive irq is clear */
		(void)tp_ops->read_status(hwif);
	}
	return rc;
}

/*
 *
 */
static void enable_nest (ide_drive_t *drive)
{
	ide_hwif_t *hwif = HWIF(drive);
	const struct ide_tp_ops *tp_ops = hwif->tp_ops;
	u8 stat;

	printk(KERN_INFO "%s: enabling %s -- ",
		hwif->name, (char *)&drive->id[ATA_ID_PROD]);

	SELECT_DRIVE(drive);
	msleep(50);
	tp_ops->exec_command(hwif, ATA_EXABYTE_ENABLE_NEST);

	if (ide_busy_sleep(hwif, WAIT_WORSTCASE, 0)) {
		printk(KERN_CONT "failed (timeout)\n");
		return;
	}

	msleep(50);

	stat = tp_ops->read_status(hwif);

	if (!OK_STAT(stat, 0, BAD_STAT))
		printk(KERN_CONT "failed (status = 0x%02x)\n", stat);
	else
		printk(KERN_CONT "success\n");
}

/**
 *	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;

	/*
	 *	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->dev_flags &= ~IDE_DFLAG_ID_READ;

	drive->id = kzalloc(SECTOR_SIZE, GFP_KERNEL);
	if (drive->id == NULL) {
		printk(KERN_ERR "ide: out of memory for id data.\n");
		return 0;
	}

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

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

		if ((drive->dev_flags & IDE_DFLAG_PRESENT) == 0)
			/* drive not found */
			return 0;

		if (strstr(m, "E X A B Y T E N E S T")) {
			enable_nest(drive);
			goto retry;
		}

		/* 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;
			}
		}
		/* drive was found */
	}

	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 !!(drive->dev_flags & IDE_DFLAG_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 int ide_register_port(ide_hwif_t *hwif)
{
	int ret;

	/* register with global device tree */
	dev_set_name(&hwif->gendev, hwif->name);
	hwif->gendev.driver_data = hwif;
	if (hwif->gendev.parent == NULL) {
		if (hwif->dev)
			hwif->gendev.parent = hwif->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",
			__func__, ret);
		goto out;
	}

	hwif->portdev = device_create(ide_port_class, &hwif->gendev,
				      MKDEV(0, 0), hwif, 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)
{
	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->dev_flags & IDE_DFLAG_NOPROBE) == 0 ||
		    (drive->dev_flags & IDE_DFLAG_PRESENT)) {
			SELECT_DRIVE(drive);
			hwif->tp_ops->set_irq(hwif, 1);
			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
 *	@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->drives[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)
{
	unsigned long flags;
	unsigned int irqd;
	int unit, rc = -ENODEV;

	BUG_ON(hwif->present);

	if ((hwif->drives[0].dev_flags & IDE_DFLAG_NOPROBE) &&
	    (hwif->drives[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);

	local_irq_set(flags);

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

		(void) probe_for_drive(drive);
		if (drive->dev_flags & IDE_DFLAG_PRESENT)
			rc = 0;
	}

	local_irq_restore(flags);

	/*
	 * 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;
	int unit;

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

		if (drive->dev_flags & IDE_DFLAG_PRESENT) {
			if (port_ops && port_ops->quirkproc)
				port_ops->quirkproc(drive);
		}
	}

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

		if (drive->dev_flags & IDE_DFLAG_PRESENT) {
			ide_set_max_pio(drive);

			drive->dev_flags |= IDE_DFLAG_NICE1;

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

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

		if ((hwif->host_flags & IDE_HFLAG_NO_IO_32BIT) ||
		    drive->id[ATA_ID_DWORD_IO])
			drive->dev_flags |= IDE_DFLAG_NO_IO_32BIT;
		else
			drive->dev_flags &= ~IDE_DFLAG_NO_IO_32BIT;
	}
}

/*
 * 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, &hwif->hwgroup->lock,
				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_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;
}

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

	spin_lock_irq(&hwgroup->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(&hwgroup->lock);
}

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

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

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

		if (ide_init_queue(drive)) {
			printk(KERN_ERR "ide: failed to init %s\n",
					drive->name);
			kfree(drive->id);
			drive->id = NULL;
			drive->dev_flags &= ~IDE_DFLAG_PRESENT;
			continue;
		}

		j++;

		ide_add_drive_to_hwgroup(drive);
	}
	mutex_unlock(&ide_cfg_mtx);

	return j;
}

static ide_hwif_t *ide_ports[MAX_HWIFS];

void ide_remove_port_from_hwgroup(ide_hwif_t *hwif)
{
	ide_hwgroup_t *hwgroup = hwif->hwgroup;

	ide_ports[hwif->index] = NULL;

	spin_lock_irq(&hwgroup->lock);
	/*
	 * Remove us from the hwgroup, and free
	 * the hwgroup if we were the only member
	 */
	if (hwif->next == hwif) {
		BUG_ON(hwgroup->hwif != hwif);
		kfree(hwgroup);
	} else {
		/* There is another interface in hwgroup.
		 * Unlink us, and set hwgroup->drive and ->hwif to
		 * something sane.
		 */
		ide_hwif_t *g = hwgroup->hwif;

		while (g->next != hwif)
			g = g->next;
		g->next = hwif->next;
		if (hwgroup->hwif == hwif) {
			/* Chose a random hwif for hwgroup->hwif.
			 * It's guaranteed that there are no drives
			 * left in the hwgroup.
			 */