libata: Initialize nbytes for internal sg commands

[linux-3.10.git] / drivers / ata / libata-core.c

/*
 *  libata-core.c - helper library for ATA
 *
 *  Maintained by:  Jeff Garzik <jgarzik@pobox.com>
 *                  Please ALWAYS copy linux-ide@vger.kernel.org
 *                  on emails.
 *
 *  Copyright 2003-2004 Red Hat, Inc.  All rights reserved.
 *  Copyright 2003-2004 Jeff Garzik
 *
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2, or (at your option)
 *  any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; see the file COPYING.  If not, write to
 *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 *
 *  libata documentation is available via 'make {ps|pdf}docs',
 *  as Documentation/DocBook/libata.*
 *
 *  Hardware documentation available from http://www.t13.org/ and
 *  http://www.sata-io.org/
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/spinlock.h>
#include <linux/blkdev.h>
#include <linux/delay.h>
#include <linux/timer.h>
#include <linux/interrupt.h>
#include <linux/completion.h>
#include <linux/suspend.h>
#include <linux/workqueue.h>
#include <linux/jiffies.h>
#include <linux/scatterlist.h>
#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_host.h>
#include <linux/libata.h>
#include <asm/io.h>
#include <asm/semaphore.h>
#include <asm/byteorder.h>

#include "libata.h"

/* debounce timing parameters in msecs { interval, duration, timeout } */
const unsigned long sata_deb_timing_normal[]            = {   5,  100, 2000 };
const unsigned long sata_deb_timing_hotplug[]           = {  25,  500, 2000 };
const unsigned long sata_deb_timing_long[]              = { 100, 2000, 5000 };

static unsigned int ata_dev_init_params(struct ata_device *dev,
                                        u16 heads, u16 sectors);
static unsigned int ata_dev_set_xfermode(struct ata_device *dev);
static void ata_dev_xfermask(struct ata_device *dev);

static unsigned int ata_unique_id = 1;
static struct workqueue_struct *ata_wq;

struct workqueue_struct *ata_aux_wq;

int atapi_enabled = 1;
module_param(atapi_enabled, int, 0444);
MODULE_PARM_DESC(atapi_enabled, "Enable discovery of ATAPI devices (0=off, 1=on)");

int atapi_dmadir = 0;
module_param(atapi_dmadir, int, 0444);
MODULE_PARM_DESC(atapi_dmadir, "Enable ATAPI DMADIR bridge support (0=off, 1=on)");

int libata_fua = 0;
module_param_named(fua, libata_fua, int, 0444);
MODULE_PARM_DESC(fua, "FUA support (0=off, 1=on)");

static int ata_probe_timeout = ATA_TMOUT_INTERNAL / HZ;
module_param(ata_probe_timeout, int, 0444);
MODULE_PARM_DESC(ata_probe_timeout, "Set ATA probing timeout (seconds)");

MODULE_AUTHOR("Jeff Garzik");
MODULE_DESCRIPTION("Library module for ATA devices");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);


/**
 *      ata_tf_to_fis - Convert ATA taskfile to SATA FIS structure
 *      @tf: Taskfile to convert
 *      @fis: Buffer into which data will output
 *      @pmp: Port multiplier port
 *
 *      Converts a standard ATA taskfile to a Serial ATA
 *      FIS structure (Register - Host to Device).
 *
 *      LOCKING:
 *      Inherited from caller.
 */

void ata_tf_to_fis(const struct ata_taskfile *tf, u8 *fis, u8 pmp)
{
        fis[0] = 0x27;  /* Register - Host to Device FIS */
        fis[1] = (pmp & 0xf) | (1 << 7); /* Port multiplier number,
                                            bit 7 indicates Command FIS */
        fis[2] = tf->command;
        fis[3] = tf->feature;

        fis[4] = tf->lbal;
        fis[5] = tf->lbam;
        fis[6] = tf->lbah;
        fis[7] = tf->device;

        fis[8] = tf->hob_lbal;
        fis[9] = tf->hob_lbam;
        fis[10] = tf->hob_lbah;
        fis[11] = tf->hob_feature;

        fis[12] = tf->nsect;
        fis[13] = tf->hob_nsect;
        fis[14] = 0;
        fis[15] = tf->ctl;

        fis[16] = 0;
        fis[17] = 0;
        fis[18] = 0;
        fis[19] = 0;
}

/**
 *      ata_tf_from_fis - Convert SATA FIS to ATA taskfile
 *      @fis: Buffer from which data will be input
 *      @tf: Taskfile to output
 *
 *      Converts a serial ATA FIS structure to a standard ATA taskfile.
 *
 *      LOCKING:
 *      Inherited from caller.
 */

void ata_tf_from_fis(const u8 *fis, struct ata_taskfile *tf)
{
        tf->command     = fis[2];       /* status */
        tf->feature     = fis[3];       /* error */

        tf->lbal        = fis[4];
        tf->lbam        = fis[5];
        tf->lbah        = fis[6];
        tf->device      = fis[7];

        tf->hob_lbal    = fis[8];
        tf->hob_lbam    = fis[9];
        tf->hob_lbah    = fis[10];

        tf->nsect       = fis[12];
        tf->hob_nsect   = fis[13];
}

static const u8 ata_rw_cmds[] = {
        /* pio multi */
        ATA_CMD_READ_MULTI,
        ATA_CMD_WRITE_MULTI,
        ATA_CMD_READ_MULTI_EXT,
        ATA_CMD_WRITE_MULTI_EXT,
        0,
        0,
        0,
        ATA_CMD_WRITE_MULTI_FUA_EXT,
        /* pio */
        ATA_CMD_PIO_READ,
        ATA_CMD_PIO_WRITE,
        ATA_CMD_PIO_READ_EXT,
        ATA_CMD_PIO_WRITE_EXT,
        0,
        0,
        0,
        0,
        /* dma */
        ATA_CMD_READ,
        ATA_CMD_WRITE,
        ATA_CMD_READ_EXT,
        ATA_CMD_WRITE_EXT,
        0,
        0,
        0,
        ATA_CMD_WRITE_FUA_EXT
};

/**
 *      ata_rwcmd_protocol - set taskfile r/w commands and protocol
 *      @tf: command to examine and configure
 *      @dev: device tf belongs to
 *
 *      Examine the device configuration and tf->flags to calculate
 *      the proper read/write commands and protocol to use.
 *
 *      LOCKING:
 *      caller.
 */
static int ata_rwcmd_protocol(struct ata_taskfile *tf, struct ata_device *dev)
{
        u8 cmd;

        int index, fua, lba48, write;

        fua = (tf->flags & ATA_TFLAG_FUA) ? 4 : 0;
        lba48 = (tf->flags & ATA_TFLAG_LBA48) ? 2 : 0;
        write = (tf->flags & ATA_TFLAG_WRITE) ? 1 : 0;

        if (dev->flags & ATA_DFLAG_PIO) {
                tf->protocol = ATA_PROT_PIO;
                index = dev->multi_count ? 0 : 8;
        } else if (lba48 && (dev->ap->flags & ATA_FLAG_PIO_LBA48)) {
                /* Unable to use DMA due to host limitation */
                tf->protocol = ATA_PROT_PIO;
                index = dev->multi_count ? 0 : 8;
        } else {
                tf->protocol = ATA_PROT_DMA;
                index = 16;
        }

        cmd = ata_rw_cmds[index + fua + lba48 + write];
        if (cmd) {
                tf->command = cmd;
                return 0;
        }
        return -1;
}

/**
 *      ata_tf_read_block - Read block address from ATA taskfile
 *      @tf: ATA taskfile of interest
 *      @dev: ATA device @tf belongs to
 *
 *      LOCKING:
 *      None.
 *
 *      Read block address from @tf.  This function can handle all
 *      three address formats - LBA, LBA48 and CHS.  tf->protocol and
 *      flags select the address format to use.
 *
 *      RETURNS:
 *      Block address read from @tf.
 */
u64 ata_tf_read_block(struct ata_taskfile *tf, struct ata_device *dev)
{
        u64 block = 0;

        if (tf->flags & ATA_TFLAG_LBA) {
                if (tf->flags & ATA_TFLAG_LBA48) {
                        block |= (u64)tf->hob_lbah << 40;
                        block |= (u64)tf->hob_lbam << 32;
                        block |= tf->hob_lbal << 24;
                } else
                        block |= (tf->device & 0xf) << 24;

                block |= tf->lbah << 16;
                block |= tf->lbam << 8;
                block |= tf->lbal;
        } else {
                u32 cyl, head, sect;

                cyl = tf->lbam | (tf->lbah << 8);
                head = tf->device & 0xf;
                sect = tf->lbal;

                block = (cyl * dev->heads + head) * dev->sectors + sect;
        }

        return block;
}

/**
 *      ata_build_rw_tf - Build ATA taskfile for given read/write request
 *      @tf: Target ATA taskfile
 *      @dev: ATA device @tf belongs to
 *      @block: Block address
 *      @n_block: Number of blocks
 *      @tf_flags: RW/FUA etc...
 *      @tag: tag
 *
 *      LOCKING:
 *      None.
 *
 *      Build ATA taskfile @tf for read/write request described by
 *      @block, @n_block, @tf_flags and @tag on @dev.
 *
 *      RETURNS:
 *
 *      0 on success, -ERANGE if the request is too large for @dev,
 *      -EINVAL if the request is invalid.
 */
int ata_build_rw_tf(struct ata_taskfile *tf, struct ata_device *dev,
                    u64 block, u32 n_block, unsigned int tf_flags,
                    unsigned int tag)
{
        tf->flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
        tf->flags |= tf_flags;

        if ((dev->flags & (ATA_DFLAG_PIO | ATA_DFLAG_NCQ_OFF |
                           ATA_DFLAG_NCQ)) == ATA_DFLAG_NCQ &&
            likely(tag != ATA_TAG_INTERNAL)) {
                /* yay, NCQ */
                if (!lba_48_ok(block, n_block))
                        return -ERANGE;

                tf->protocol = ATA_PROT_NCQ;
                tf->flags |= ATA_TFLAG_LBA | ATA_TFLAG_LBA48;

                if (tf->flags & ATA_TFLAG_WRITE)
                        tf->command = ATA_CMD_FPDMA_WRITE;
                else
                        tf->command = ATA_CMD_FPDMA_READ;

                tf->nsect = tag << 3;
                tf->hob_feature = (n_block >> 8) & 0xff;
                tf->feature = n_block & 0xff;

                tf->hob_lbah = (block >> 40) & 0xff;
                tf->hob_lbam = (block >> 32) & 0xff;
                tf->hob_lbal = (block >> 24) & 0xff;
                tf->lbah = (block >> 16) & 0xff;
                tf->lbam = (block >> 8) & 0xff;
                tf->lbal = block & 0xff;

                tf->device = 1 << 6;
                if (tf->flags & ATA_TFLAG_FUA)
                        tf->device |= 1 << 7;
        } else if (dev->flags & ATA_DFLAG_LBA) {
                tf->flags |= ATA_TFLAG_LBA;

                if (lba_28_ok(block, n_block)) {
                        /* use LBA28 */
                        tf->device |= (block >> 24) & 0xf;
                } else if (lba_48_ok(block, n_block)) {
                        if (!(dev->flags & ATA_DFLAG_LBA48))
                                return -ERANGE;

                        /* use LBA48 */
                        tf->flags |= ATA_TFLAG_LBA48;

                        tf->hob_nsect = (n_block >> 8) & 0xff;

                        tf->hob_lbah = (block >> 40) & 0xff;
                        tf->hob_lbam = (block >> 32) & 0xff;
                        tf->hob_lbal = (block >> 24) & 0xff;
                } else
                        /* request too large even for LBA48 */
                        return -ERANGE;

                if (unlikely(ata_rwcmd_protocol(tf, dev) < 0))
                        return -EINVAL;

                tf->nsect = n_block & 0xff;

                tf->lbah = (block >> 16) & 0xff;
                tf->lbam = (block >> 8) & 0xff;
                tf->lbal = block & 0xff;

                tf->device |= ATA_LBA;
        } else {
                /* CHS */
                u32 sect, head, cyl, track;

                /* The request -may- be too large for CHS addressing. */
                if (!lba_28_ok(block, n_block))
                        return -ERANGE;

                if (unlikely(ata_rwcmd_protocol(tf, dev) < 0))
                        return -EINVAL;

                /* Convert LBA to CHS */
                track = (u32)block / dev->sectors;
                cyl   = track / dev->heads;
                head  = track % dev->heads;
                sect  = (u32)block % dev->sectors + 1;

                DPRINTK("block %u track %u cyl %u head %u sect %u\n",
                        (u32)block, track, cyl, head, sect);

                /* Check whether the converted CHS can fit.
                   Cylinder: 0-65535
                   Head: 0-15
                   Sector: 1-255*/
                if ((cyl >> 16) || (head >> 4) || (sect >> 8) || (!sect))
                        return -ERANGE;

                tf->nsect = n_block & 0xff; /* Sector count 0 means 256 sectors */
                tf->lbal = sect;
                tf->lbam = cyl;
                tf->lbah = cyl >> 8;
                tf->device |= head;
        }

        return 0;
}

/**
 *      ata_pack_xfermask - Pack pio, mwdma and udma masks into xfer_mask
 *      @pio_mask: pio_mask
 *      @mwdma_mask: mwdma_mask
 *      @udma_mask: udma_mask
 *
 *      Pack @pio_mask, @mwdma_mask and @udma_mask into a single
 *      unsigned int xfer_mask.
 *
 *      LOCKING:
 *      None.
 *
 *      RETURNS:
 *      Packed xfer_mask.
 */
static unsigned int ata_pack_xfermask(unsigned int pio_mask,
                                      unsigned int mwdma_mask,
                                      unsigned int udma_mask)
{
        return ((pio_mask << ATA_SHIFT_PIO) & ATA_MASK_PIO) |
                ((mwdma_mask << ATA_SHIFT_MWDMA) & ATA_MASK_MWDMA) |
                ((udma_mask << ATA_SHIFT_UDMA) & ATA_MASK_UDMA);
}

/**
 *      ata_unpack_xfermask - Unpack xfer_mask into pio, mwdma and udma masks
 *      @xfer_mask: xfer_mask to unpack
 *      @pio_mask: resulting pio_mask
 *      @mwdma_mask: resulting mwdma_mask
 *      @udma_mask: resulting udma_mask
 *
 *      Unpack @xfer_mask into @pio_mask, @mwdma_mask and @udma_mask.
 *      Any NULL distination masks will be ignored.
 */
static void ata_unpack_xfermask(unsigned int xfer_mask,
                                unsigned int *pio_mask,
                                unsigned int *mwdma_mask,
                                unsigned int *udma_mask)
{
        if (pio_mask)
                *pio_mask = (xfer_mask & ATA_MASK_PIO) >> ATA_SHIFT_PIO;
        if (mwdma_mask)
                *mwdma_mask = (xfer_mask & ATA_MASK_MWDMA) >> ATA_SHIFT_MWDMA;
        if (udma_mask)
                *udma_mask = (xfer_mask & ATA_MASK_UDMA) >> ATA_SHIFT_UDMA;
}

static const struct ata_xfer_ent {
        int shift, bits;
        u8 base;
} ata_xfer_tbl[] = {
        { ATA_SHIFT_PIO, ATA_BITS_PIO, XFER_PIO_0 },
        { ATA_SHIFT_MWDMA, ATA_BITS_MWDMA, XFER_MW_DMA_0 },
        { ATA_SHIFT_UDMA, ATA_BITS_UDMA, XFER_UDMA_0 },
        { -1, },
};

/**
 *      ata_xfer_mask2mode - Find matching XFER_* for the given xfer_mask
 *      @xfer_mask: xfer_mask of interest
 *
 *      Return matching XFER_* value for @xfer_mask.  Only the highest
 *      bit of @xfer_mask is considered.
 *
 *      LOCKING:
 *      None.
 *
 *      RETURNS:
 *      Matching XFER_* value, 0 if no match found.
 */
static u8 ata_xfer_mask2mode(unsigned int xfer_mask)
{
        int highbit = fls(xfer_mask) - 1;
        const struct ata_xfer_ent *ent;

        for (ent = ata_xfer_tbl; ent->shift >= 0; ent++)
                if (highbit >= ent->shift && highbit < ent->shift + ent->bits)
                        return ent->base + highbit - ent->shift;
        return 0;
}

/**
 *      ata_xfer_mode2mask - Find matching xfer_mask for XFER_*
 *      @xfer_mode: XFER_* of interest
 *
 *      Return matching xfer_mask for @xfer_mode.
 *
 *      LOCKING:
 *      None.
 *
 *      RETURNS:
 *      Matching xfer_mask, 0 if no match found.
 */
static unsigned int ata_xfer_mode2mask(u8 xfer_mode)
{
        const struct ata_xfer_ent *ent;

        for (ent = ata_xfer_tbl; ent->shift >= 0; ent++)
                if (xfer_mode >= ent->base && xfer_mode < ent->base + ent->bits)
                        return 1 << (ent->shift + xfer_mode - ent->base);
        return 0;
}

/**
 *      ata_xfer_mode2shift - Find matching xfer_shift for XFER_*
 *      @xfer_mode: XFER_* of interest
 *
 *      Return matching xfer_shift for @xfer_mode.
 *
 *      LOCKING:
 *      None.
 *
 *      RETURNS:
 *      Matching xfer_shift, -1 if no match found.
 */
static int ata_xfer_mode2shift(unsigned int xfer_mode)
{
        const struct ata_xfer_ent *ent;

        for (ent = ata_xfer_tbl; ent->shift >= 0; ent++)
                if (xfer_mode >= ent->base && xfer_mode < ent->base + ent->bits)
                        return ent->shift;
        return -1;
}

/**
 *      ata_mode_string - convert xfer_mask to string
 *      @xfer_mask: mask of bits supported; only highest bit counts.
 *
 *      Determine string which represents the highest speed
 *      (highest bit in @modemask).
 *
 *      LOCKING:
 *      None.
 *
 *      RETURNS:
 *      Constant C string representing highest speed listed in
 *      @mode_mask, or the constant C string "<n/a>".
 */
static const char *ata_mode_string(unsigned int xfer_mask)
{
        static const char * const xfer_mode_str[] = {
                "PIO0",
                "PIO1",
                "PIO2",
                "PIO3",
                "PIO4",
                "PIO5",
                "PIO6",
                "MWDMA0",
                "MWDMA1",
                "MWDMA2",
                "MWDMA3",
                "MWDMA4",
                "UDMA/16",
                "UDMA/25",
                "UDMA/33",
                "UDMA/44",
                "UDMA/66",
                "UDMA/100",
                "UDMA/133",
                "UDMA7",
        };
        int highbit;

        highbit = fls(xfer_mask) - 1;
        if (highbit >= 0 && highbit < ARRAY_SIZE(xfer_mode_str))
                return xfer_mode_str[highbit];
        return "<n/a>";
}

static const char *sata_spd_string(unsigned int spd)
{
        static const char * const spd_str[] = {
                "1.5 Gbps",
                "3.0 Gbps",
        };

        if (spd == 0 || (spd - 1) >= ARRAY_SIZE(spd_str))
                return "<unknown>";
        return spd_str[spd - 1];
}

void ata_dev_disable(struct ata_device *dev)
{
        if (ata_dev_enabled(dev) && ata_msg_drv(dev->ap)) {
                ata_dev_printk(dev, KERN_WARNING, "disabled\n");
                dev->class++;
        }
}

/**
 *      ata_pio_devchk - PATA device presence detection
 *      @ap: ATA channel to examine
 *      @device: Device to examine (starting at zero)
 *
 *      This technique was originally described in
 *      Hale Landis's ATADRVR (www.ata-atapi.com), and
 *      later found its way into the ATA/ATAPI spec.
 *
 *      Write a pattern to the ATA shadow registers,
 *      and if a device is present, it will respond by
 *      correctly storing and echoing back the
 *      ATA shadow register contents.
 *
 *      LOCKING:
 *      caller.
 */

static unsigned int ata_pio_devchk(struct ata_port *ap,
                                   unsigned int device)
{
        struct ata_ioports *ioaddr = &ap->ioaddr;
        u8 nsect, lbal;

        ap->ops->dev_select(ap, device);

        outb(0x55, ioaddr->nsect_addr);
        outb(0xaa, ioaddr->lbal_addr);

        outb(0xaa, ioaddr->nsect_addr);
        outb(0x55, ioaddr->lbal_addr);

        outb(0x55, ioaddr->nsect_addr);
        outb(0xaa, ioaddr->lbal_addr);

        nsect = inb(ioaddr->nsect_addr);
        lbal = inb(ioaddr->lbal_addr);

        if ((nsect == 0x55) && (lbal == 0xaa))
                return 1;       /* we found a device */

        return 0;               /* nothing found */
}

/**
 *      ata_mmio_devchk - PATA device presence detection
 *      @ap: ATA channel to examine
 *      @device: Device to examine (starting at zero)
 *
 *      This technique was originally described in
 *      Hale Landis's ATADRVR (www.ata-atapi.com), and
 *      later found its way into the ATA/ATAPI spec.
 *
 *      Write a pattern to the ATA shadow registers,
 *      and if a device is present, it will respond by
 *      correctly storing and echoing back the
 *      ATA shadow register contents.
 *
 *      LOCKING:
 *      caller.
 */

static unsigned int ata_mmio_devchk(struct ata_port *ap,
                                    unsigned int device)
{
        struct ata_ioports *ioaddr = &ap->ioaddr;
        u8 nsect, lbal;

        ap->ops->dev_select(ap, device);

        writeb(0x55, (void __iomem *) ioaddr->nsect_addr);
        writeb(0xaa, (void __iomem *) ioaddr->lbal_addr);

        writeb(0xaa, (void __iomem *) ioaddr->nsect_addr);
        writeb(0x55, (void __iomem *) ioaddr->lbal_addr);

        writeb(0x55, (void __iomem *) ioaddr->nsect_addr);
        writeb(0xaa, (void __iomem *) ioaddr->lbal_addr);

        nsect = readb((void __iomem *) ioaddr->nsect_addr);
        lbal = readb((void __iomem *) ioaddr->lbal_addr);

        if ((nsect == 0x55) && (lbal == 0xaa))
                return 1;       /* we found a device */

        return 0;               /* nothing found */
}

/**
 *      ata_devchk - PATA device presence detection
 *      @ap: ATA channel to examine
 *      @device: Device to examine (starting at zero)
 *
 *      Dispatch ATA device presence detection, depending
 *      on whether we are using PIO or MMIO to talk to the
 *      ATA shadow registers.
 *
 *      LOCKING:
 *      caller.
 */

static unsigned int ata_devchk(struct ata_port *ap,
                                    unsigned int device)
{
        if (ap->flags & ATA_FLAG_MMIO)
                return ata_mmio_devchk(ap, device);
        return ata_pio_devchk(ap, device);
}

/**
 *      ata_dev_classify - determine device type based on ATA-spec signature
 *      @tf: ATA taskfile register set for device to be identified
 *
 *      Determine from taskfile register contents whether a device is
 *      ATA or ATAPI, as per "Signature and persistence" section
 *      of ATA/PI spec (volume 1, sect 5.14).
 *
 *      LOCKING:
 *      None.
 *
 *      RETURNS:
 *      Device type, %ATA_DEV_ATA, %ATA_DEV_ATAPI, or %ATA_DEV_UNKNOWN
 *      the event of failure.
 */

unsigned int ata_dev_classify(const struct ata_taskfile *tf)
{
        /* Apple's open source Darwin code hints that some devices only
         * put a proper signature into the LBA mid/high registers,
         * So, we only check those.  It's sufficient for uniqueness.
         */

        if (((tf->lbam == 0) && (tf->lbah == 0)) ||
            ((tf->lbam == 0x3c) && (tf->lbah == 0xc3))) {
                DPRINTK("found ATA device by sig\n");
                return ATA_DEV_ATA;
        }

        if (((tf->lbam == 0x14) && (tf->lbah == 0xeb)) ||
            ((tf->lbam == 0x69) && (tf->lbah == 0x96))) {
                DPRINTK("found ATAPI device by sig\n");
                return ATA_DEV_ATAPI;
        }

        DPRINTK("unknown device\n");
        return ATA_DEV_UNKNOWN;
}

/**
 *      ata_dev_try_classify - Parse returned ATA device signature
 *      @ap: ATA channel to examine
 *      @device: Device to examine (starting at zero)
 *      @r_err: Value of error register on completion
 *
 *      After an event -- SRST, E.D.D., or SATA COMRESET -- occurs,
 *      an ATA/ATAPI-defined set of values is placed in the ATA
 *      shadow registers, indicating the results of device detection
 *      and diagnostics.
 *
 *      Select the ATA device, and read the values from the ATA shadow
 *      registers.  Then parse according to the Error register value,
 *      and the spec-defined values examined by ata_dev_classify().
 *
 *      LOCKING:
 *      caller.
 *
 *      RETURNS:
 *      Device type - %ATA_DEV_ATA, %ATA_DEV_ATAPI or %ATA_DEV_NONE.
 */

static unsigned int
ata_dev_try_classify(struct ata_port *ap, unsigned int device, u8 *r_err)
{
        struct ata_taskfile tf;
        unsigned int class;
        u8 err;

        ap->ops->dev_select(ap, device);

        memset(&tf, 0, sizeof(tf));

        ap->ops->tf_read(ap, &tf);
        err = tf.feature;
        if (r_err)
                *r_err = err;

        /* see if device passed diags: if master then continue and warn later */
        if (err == 0 && device == 0)
                /* diagnostic fail : do nothing _YET_ */
                ap->device[device].horkage |= ATA_HORKAGE_DIAGNOSTIC;
        else if (err == 1)
                /* do nothing */ ;
        else if ((device == 0) && (err == 0x81))
                /* do nothing */ ;
        else
                return ATA_DEV_NONE;

        /* determine if device is ATA or ATAPI */
        class = ata_dev_classify(&tf);

        if (class == ATA_DEV_UNKNOWN)
                return ATA_DEV_NONE;
        if ((class == ATA_DEV_ATA) && (ata_chk_status(ap) == 0))
                return ATA_DEV_NONE;
        return class;
}

/**
 *      ata_id_string - Convert IDENTIFY DEVICE page into string
 *      @id: IDENTIFY DEVICE results we will examine
 *      @s: string into which data is output
 *      @ofs: offset into identify device page
 *      @len: length of string to return. must be an even number.
 *
 *      The strings in the IDENTIFY DEVICE page are broken up into
 *      16-bit chunks.  Run through the string, and output each
 *      8-bit chunk linearly, regardless of platform.
 *
 *      LOCKING:
 *      caller.
 */

void ata_id_string(const u16 *id, unsigned char *s,
                   unsigned int ofs, unsigned int len)
{
        unsigned int c;

        while (len > 0) {
                c = id[ofs] >> 8;
                *s = c;
                s++;

                c = id[ofs] & 0xff;
                *s = c;
                s++;

                ofs++;
                len -= 2;
        }
}

/**
 *      ata_id_c_string - Convert IDENTIFY DEVICE page into C string
 *      @id: IDENTIFY DEVICE results we will examine
 *      @s: string into which data is output
 *      @ofs: offset into identify device page
 *      @len: length of string to return. must be an odd number.
 *
 *      This function is identical to ata_id_string except that it
 *      trims trailing spaces and terminates the resulting string with
 *      null.  @len must be actual maximum length (even number) + 1.
 *
 *      LOCKING:
 *      caller.
 */
void ata_id_c_string(const u16 *id, unsigned char *s,
                     unsigned int ofs, unsigned int len)
{
        unsigned char *p;

        WARN_ON(!(len & 1));

        ata_id_string(id, s, ofs, len - 1);

        p = s + strnlen(s, len - 1);
        while (p > s && p[-1] == ' ')
                p--;
        *p = '\0';
}

static u64 ata_id_n_sectors(const u16 *id)
{
        if (ata_id_has_lba(id)) {
                if (ata_id_has_lba48(id))
                        return ata_id_u64(id, 100);
                else
                        return ata_id_u32(id, 60);
        } else {
                if (ata_id_current_chs_valid(id))
                        return ata_id_u32(id, 57);
                else
                        return id[1] * id[3] * id[6];
        }
}

/**
 *      ata_noop_dev_select - Select device 0/1 on ATA bus
 *      @ap: ATA channel to manipulate
 *      @device: ATA device (numbered from zero) to select
 *
 *      This function performs no actual function.
 *
 *      May be used as the dev_select() entry in ata_port_operations.
 *
 *      LOCKING:
 *      caller.
 */
void ata_noop_dev_select (struct ata_port *ap, unsigned int device)
{
}


/**
 *      ata_std_dev_select - Select device 0/1 on ATA bus
 *      @ap: ATA channel to manipulate
 *      @device: ATA device (numbered from zero) to select
 *
 *      Use the method defined in the ATA specification to
 *      make either device 0, or device 1, active on the
 *      ATA channel.  Works with both PIO and MMIO.
 *
 *      May be used as the dev_select() entry in ata_port_operations.
 *
 *      LOCKING:
 *      caller.
 */

void ata_std_dev_select (struct ata_port *ap, unsigned int device)
{
        u8 tmp;

        if (device == 0)
                tmp = ATA_DEVICE_OBS;
        else
                tmp = ATA_DEVICE_OBS | ATA_DEV1;

        if (ap->flags & ATA_FLAG_MMIO) {
                writeb(tmp, (void __iomem *) ap->ioaddr.device_addr);
        } else {
                outb(tmp, ap->ioaddr.device_addr);
        }
        ata_pause(ap);          /* needed; also flushes, for mmio */
}

/**
 *      ata_dev_select - Select device 0/1 on ATA bus
 *      @ap: ATA channel to manipulate
 *      @device: ATA device (numbered from zero) to select
 *      @wait: non-zero to wait for Status register BSY bit to clear
 *      @can_sleep: non-zero if context allows sleeping
 *
 *      Use the method defined in the ATA specification to
 *      make either device 0, or device 1, active on the
 *      ATA channel.
 *
 *      This is a high-level version of ata_std_dev_select(),
 *      which additionally provides the services of inserting
 *      the proper pauses and status polling, where needed.
 *
 *      LOCKING:
 *      caller.
 */

void ata_dev_select(struct ata_port *ap, unsigned int device,
                           unsigned int wait, unsigned int can_sleep)
{
        if (ata_msg_probe(ap))
                ata_port_printk(ap, KERN_INFO, "ata_dev_select: ENTER, ata%u: "
                                "device %u, wait %u\n", ap->id, device, wait);

        if (wait)
                ata_wait_idle(ap);

        ap->ops->dev_select(ap, device);

        if (wait) {
                if (can_sleep && ap->device[device].class == ATA_DEV_ATAPI)
                        msleep(150);
                ata_wait_idle(ap);
        }
}

/**
 *      ata_dump_id - IDENTIFY DEVICE info debugging output
 *      @id: IDENTIFY DEVICE page to dump
 *
 *      Dump selected 16-bit words from the given IDENTIFY DEVICE
 *      page.
 *
 *      LOCKING:
 *      caller.
 */

static inline void ata_dump_id(const u16 *id)
{
        DPRINTK("49==0x%04x  "
                "53==0x%04x  "
                "63==0x%04x  "
                "64==0x%04x  "
                "75==0x%04x  \n",
                id[49],
                id[53],
                id[63],
                id[64],
                id[75]);
        DPRINTK("80==0x%04x  "
                "81==0x%04x  "
                "82==0x%04x  "
                "83==0x%04x  "
                "84==0x%04x  \n",
                id[80],
                id[81],
                id[82],
                id[83],
                id[84]);
        DPRINTK("88==0x%04x  "
                "93==0x%04x\n",
                id[88],
                id[93]);
}

/**
 *      ata_id_xfermask - Compute xfermask from the given IDENTIFY data
 *      @id: IDENTIFY data to compute xfer mask from
 *
 *      Compute the xfermask for this device. This is not as trivial
 *      as it seems if we must consider early devices correctly.
 *
 *      FIXME: pre IDE drive timing (do we care ?).
 *
 *      LOCKING:
 *      None.
 *
 *      RETURNS:
 *      Computed xfermask
 */
static unsigned int ata_id_xfermask(const u16 *id)
{
        unsigned int pio_mask, mwdma_mask, udma_mask;

        /* Usual case. Word 53 indicates word 64 is valid */
        if (id[ATA_ID_FIELD_VALID] & (1 << 1)) {
                pio_mask = id[ATA_ID_PIO_MODES] & 0x03;
                pio_mask <<= 3;
                pio_mask |= 0x7;
        } else {
                /* If word 64 isn't valid then Word 51 high byte holds
                 * the PIO timing number for the maximum. Turn it into
                 * a mask.
                 */
                u8 mode = (id[ATA_ID_OLD_PIO_MODES] >> 8) & 0xFF;
                if (mode < 5)   /* Valid PIO range */
                        pio_mask = (2 << mode) - 1;
                else
                        pio_mask = 1;

                /* But wait.. there's more. Design your standards by
                 * committee and you too can get a free iordy field to
                 * process. However its the speeds not the modes that
                 * are supported... Note drivers using the timing API
                 * will get this right anyway
                 */
        }

        mwdma_mask = id[ATA_ID_MWDMA_MODES] & 0x07;

        if (ata_id_is_cfa(id)) {
                /*
                 *      Process compact flash extended modes
                 */
                int pio = id[163] & 0x7;
                int dma = (id[163] >> 3) & 7;

                if (pio)
                        pio_mask |= (1 << 5);
                if (pio > 1)
                        pio_mask |= (1 << 6);
                if (dma)
                        mwdma_mask |= (1 << 3);
                if (dma > 1)
                        mwdma_mask |= (1 << 4);
        }

        udma_mask = 0;
        if (id[ATA_ID_FIELD_VALID] & (1 << 2))
                udma_mask = id[ATA_ID_UDMA_MODES] & 0xff;

        return ata_pack_xfermask(pio_mask, mwdma_mask, udma_mask);
}

/**
 *      ata_port_queue_task - Queue port_task
 *      @ap: The ata_port to queue port_task for
 *      @fn: workqueue function to be scheduled
 *      @data: data for @fn to use
 *      @delay: delay time for workqueue function
 *
 *      Schedule @fn(@data) for execution after @delay jiffies using
 *      port_task.  There is one port_task per port and it's the
 *      user(low level driver)'s responsibility to make sure that only
 *      one task is active at any given time.
 *
 *      libata core layer takes care of synchronization between
 *      port_task and EH.  ata_port_queue_task() may be ignored for EH
 *      synchronization.
 *
 *      LOCKING:
 *      Inherited from caller.
 */
void ata_port_queue_task(struct ata_port *ap, work_func_t fn, void *data,
                         unsigned long delay)
{
        int rc;

        if (ap->pflags & ATA_PFLAG_FLUSH_PORT_TASK)
                return;

        PREPARE_DELAYED_WORK(&ap->port_task, fn);
        ap->port_task_data = data;

        rc = queue_delayed_work(ata_wq, &ap->port_task, delay);

        /* rc == 0 means that another user is using port task */
        WARN_ON(rc == 0);
}

/**
 *      ata_port_flush_task - Flush port_task
 *      @ap: The ata_port to flush port_task for
 *
 *      After this function completes, port_task is guranteed not to
 *      be running or scheduled.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep)
 */
void ata_port_flush_task(struct ata_port *ap)
{
        unsigned long flags;

        DPRINTK("ENTER\n");

        spin_lock_irqsave(ap->lock, flags);
        ap->pflags |= ATA_PFLAG_FLUSH_PORT_TASK;
        spin_unlock_irqrestore(ap->lock, flags);

        DPRINTK("flush #1\n");
        flush_workqueue(ata_wq);

        /*
         * At this point, if a task is running, it's guaranteed to see
         * the FLUSH flag; thus, it will never queue pio tasks again.
         * Cancel and flush.
         */
        if (!cancel_delayed_work(&ap->port_task)) {
                if (ata_msg_ctl(ap))
                        ata_port_printk(ap, KERN_DEBUG, "%s: flush #2\n",
                                        __FUNCTION__);
                flush_workqueue(ata_wq);
        }

        spin_lock_irqsave(ap->lock, flags);
        ap->pflags &= ~ATA_PFLAG_FLUSH_PORT_TASK;
        spin_unlock_irqrestore(ap->lock, flags);

        if (ata_msg_ctl(ap))
                ata_port_printk(ap, KERN_DEBUG, "%s: EXIT\n", __FUNCTION__);
}

void ata_qc_complete_internal(struct ata_queued_cmd *qc)
{
        struct completion *waiting = qc->private_data;

        complete(waiting);
}

/**
 *      ata_exec_internal_sg - execute libata internal command
 *      @dev: Device to which the command is sent
 *      @tf: Taskfile registers for the command and the result
 *      @cdb: CDB for packet command
 *      @dma_dir: Data tranfer direction of the command
 *      @sg: sg list for the data buffer of the command
 *      @n_elem: Number of sg entries
 *
 *      Executes libata internal command with timeout.  @tf contains
 *      command on entry and result on return.  Timeout and error
 *      conditions are reported via return value.  No recovery action
 *      is taken after a command times out.  It's caller's duty to
 *      clean up after timeout.
 *
 *      LOCKING:
 *      None.  Should be called with kernel context, might sleep.
 *
 *      RETURNS:
 *      Zero on success, AC_ERR_* mask on failure
 */
unsigned ata_exec_internal_sg(struct ata_device *dev,
                              struct ata_taskfile *tf, const u8 *cdb,
                              int dma_dir, struct scatterlist *sg,
                              unsigned int n_elem)
{
        struct ata_port *ap = dev->ap;
        u8 command = tf->command;
        struct ata_queued_cmd *qc;
        unsigned int tag, preempted_tag;
        u32 preempted_sactive, preempted_qc_active;
        DECLARE_COMPLETION_ONSTACK(wait);
        unsigned long flags;
        unsigned int err_mask;
        int rc;

        spin_lock_irqsave(ap->lock, flags);

        /* no internal command while frozen */
        if (ap->pflags & ATA_PFLAG_FROZEN) {
                spin_unlock_irqrestore(ap->lock, flags);
                return AC_ERR_SYSTEM;
        }

        /* initialize internal qc */

        /* XXX: Tag 0 is used for drivers with legacy EH as some
         * drivers choke if any other tag is given.  This breaks
         * ata_tag_internal() test for those drivers.  Don't use new
         * EH stuff without converting to it.
         */
        if (ap->ops->error_handler)
                tag = ATA_TAG_INTERNAL;
        else
                tag = 0;

        if (test_and_set_bit(tag, &ap->qc_allocated))
                BUG();
        qc = __ata_qc_from_tag(ap, tag);

        qc->tag = tag;
        qc->scsicmd = NULL;
        qc->ap = ap;
        qc->dev = dev;
        ata_qc_reinit(qc);

        preempted_tag = ap->active_tag;
        preempted_sactive = ap->sactive;
        preempted_qc_active = ap->qc_active;
        ap->active_tag = ATA_TAG_POISON;
        ap->sactive = 0;
        ap->qc_active = 0;

        /* prepare & issue qc */
        qc->tf = *tf;
        if (cdb)
                memcpy(qc->cdb, cdb, ATAPI_CDB_LEN);
        qc->flags |= ATA_QCFLAG_RESULT_TF;
        qc->dma_dir = dma_dir;
        if (dma_dir != DMA_NONE) {
                unsigned int i, buflen = 0;

                for (i = 0; i < n_elem; i++)
                        buflen += sg[i].length;

                ata_sg_init(qc, sg, n_elem);
                qc->nsect = buflen / ATA_SECT_SIZE;
                qc->nbytes = buflen;
        }

        qc->private_data = &wait;
        qc->complete_fn = ata_qc_complete_internal;

        ata_qc_issue(qc);

        spin_unlock_irqrestore(ap->lock, flags);

        rc = wait_for_completion_timeout(&wait, ata_probe_timeout);

        ata_port_flush_task(ap);

        if (!rc) {
                spin_lock_irqsave(ap->lock, flags);

                /* We're racing with irq here.  If we lose, the
                 * following test prevents us from completing the qc
                 * twice.  If we win, the port is frozen and will be
                 * cleaned up by ->post_internal_cmd().
                 */
                if (qc->flags & ATA_QCFLAG_ACTIVE) {
                        qc->err_mask |= AC_ERR_TIMEOUT;

                        if (ap->ops->error_handler)
                                ata_port_freeze(ap);
                        else
                                ata_qc_complete(qc);

                        if (ata_msg_warn(ap))
                                ata_dev_printk(dev, KERN_WARNING,
                                        "qc timeout (cmd 0x%x)\n", command);
                }

                spin_unlock_irqrestore(ap->lock, flags);
        }

        /* do post_internal_cmd */
        if (ap->ops->post_internal_cmd)
                ap->ops->post_internal_cmd(qc);

        if (qc->flags & ATA_QCFLAG_FAILED && !qc->err_mask) {
                if (ata_msg_warn(ap))
                        ata_dev_printk(dev, KERN_WARNING,
                                "zero err_mask for failed "
                                "internal command, assuming AC_ERR_OTHER\n");
                qc->err_mask |= AC_ERR_OTHER;
        }

        /* finish up */
        spin_lock_irqsave(ap->lock, flags);

        *tf = qc->result_tf;
        err_mask = qc->err_mask;

        ata_qc_free(qc);
        ap->active_tag = preempted_tag;
        ap->sactive = preempted_sactive;
        ap->qc_active = preempted_qc_active;

        /* XXX - Some LLDDs (sata_mv) disable port on command failure.
         * Until those drivers are fixed, we detect the condition
         * here, fail the command with AC_ERR_SYSTEM and reenable the
         * port.
         *
         * Note that this doesn't change any behavior as internal
         * command failure results in disabling the device in the
         * higher layer for LLDDs without new reset/EH callbacks.
         *
         * Kill the following code as soon as those drivers are fixed.
         */
        if (ap->flags & ATA_FLAG_DISABLED) {
                err_mask |= AC_ERR_SYSTEM;
                ata_port_probe(ap);
        }

        spin_unlock_irqrestore(ap->lock, flags);

        return err_mask;
}

/**
 *      ata_exec_internal - execute libata internal command
 *      @dev: Device to which the command is sent
 *      @tf: Taskfile registers for the command and the result
 *      @cdb: CDB for packet command
 *      @dma_dir: Data tranfer direction of the command
 *      @buf: Data buffer of the command
 *      @buflen: Length of data buffer
 *
 *      Wrapper around ata_exec_internal_sg() which takes simple
 *      buffer instead of sg list.
 *
 *      LOCKING:
 *      None.  Should be called with kernel context, might sleep.
 *
 *      RETURNS:
 *      Zero on success, AC_ERR_* mask on failure
 */
unsigned ata_exec_internal(struct ata_device *dev,
                           struct ata_taskfile *tf, const u8 *cdb,
                           int dma_dir, void *buf, unsigned int buflen)
{
        struct scatterlist *psg = NULL, sg;
        unsigned int n_elem = 0;

        if (dma_dir != DMA_NONE) {
                WARN_ON(!buf);
                sg_init_one(&sg, buf, buflen);
                psg = &sg;
                n_elem++;
        }

        return ata_exec_internal_sg(dev, tf, cdb, dma_dir, psg, n_elem);
}

/**
 *      ata_do_simple_cmd - execute simple internal command
 *      @dev: Device to which the command is sent
 *      @cmd: Opcode to execute
 *
 *      Execute a 'simple' command, that only consists of the opcode
 *      'cmd' itself, without filling any other registers
 *
 *      LOCKING:
 *      Kernel thread context (may sleep).
 *
 *      RETURNS:
 *      Zero on success, AC_ERR_* mask on failure
 */
unsigned int ata_do_simple_cmd(struct ata_device *dev, u8 cmd)
{
        struct ata_taskfile tf;

        ata_tf_init(dev, &tf);

        tf.command = cmd;
        tf.flags |= ATA_TFLAG_DEVICE;
        tf.protocol = ATA_PROT_NODATA;

        return ata_exec_internal(dev, &tf, NULL, DMA_NONE, NULL, 0);
}

/**
 *      ata_pio_need_iordy      -       check if iordy needed
 *      @adev: ATA device
 *
 *      Check if the current speed of the device requires IORDY. Used
 *      by various controllers for chip configuration.
 */

unsigned int ata_pio_need_iordy(const struct ata_device *adev)
{
        int pio;
        int speed = adev->pio_mode - XFER_PIO_0;

        if (speed < 2)
                return 0;
        if (speed > 2)
                return 1;

        /* If we have no drive specific rule, then PIO 2 is non IORDY */

        if (adev->id[ATA_ID_FIELD_VALID] & 2) { /* EIDE */
                pio = adev->id[ATA_ID_EIDE_PIO];
                /* Is the speed faster than the drive allows non IORDY ? */
                if (pio) {
                        /* This is cycle times not frequency - watch the logic! */
                        if (pio > 240)  /* PIO2 is 240nS per cycle */
                                return 1;
                        return 0;
                }
        }
        return 0;
}

/**
 *      ata_dev_read_id - Read ID data from the specified device
 *      @dev: target device
 *      @p_class: pointer to class of the target device (may be changed)
 *      @flags: ATA_READID_* flags
 *      @id: buffer to read IDENTIFY data into
 *
 *      Read ID data from the specified device.  ATA_CMD_ID_ATA is
 *      performed on ATA devices and ATA_CMD_ID_ATAPI on ATAPI
 *      devices.  This function also issues ATA_CMD_INIT_DEV_PARAMS
 *      for pre-ATA4 drives.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep)
 *
 *      RETURNS:
 *      0 on success, -errno otherwise.
 */
int ata_dev_read_id(struct ata_device *dev, unsigned int *p_class,
                    unsigned int flags, u16 *id)
{
        struct ata_port *ap = dev->ap;
        unsigned int class = *p_class;
        struct ata_taskfile tf;
        unsigned int err_mask = 0;
        const char *reason;
        int rc;

        if (ata_msg_ctl(ap))
                ata_dev_printk(dev, KERN_DEBUG, "%s: ENTER, host %u, dev %u\n",
                               __FUNCTION__, ap->id, dev->devno);

        ata_dev_select(ap, dev->devno, 1, 1); /* select device 0/1 */

 retry:
        ata_tf_init(dev, &tf);

        switch (class) {
        case ATA_DEV_ATA:
                tf.command = ATA_CMD_ID_ATA;
                break;
        case ATA_DEV_ATAPI:
                tf.command = ATA_CMD_ID_ATAPI;
                break;
        default:
                rc = -ENODEV;
                reason = "unsupported class";
                goto err_out;
        }

        tf.protocol = ATA_PROT_PIO;
        tf.flags |= ATA_TFLAG_POLLING; /* for polling presence detection */

        err_mask = ata_exec_internal(dev, &tf, NULL, DMA_FROM_DEVICE,
                                     id, sizeof(id[0]) * ATA_ID_WORDS);
        if (err_mask) {
                if (err_mask & AC_ERR_NODEV_HINT) {
                        DPRINTK("ata%u.%d: NODEV after polling detection\n",
                                ap->id, dev->devno);
                        return -ENOENT;
                }

                rc = -EIO;
                reason = "I/O error";
                goto err_out;
        }

        swap_buf_le16(id, ATA_ID_WORDS);

        /* sanity check */
        rc = -EINVAL;
        reason = "device reports illegal type";

        if (class == ATA_DEV_ATA) {
                if (!ata_id_is_ata(id) && !ata_id_is_cfa(id))
                        goto err_out;
        } else {
                if (ata_id_is_ata(id))
                        goto err_out;
        }

        if ((flags & ATA_READID_POSTRESET) && class == ATA_DEV_ATA) {
                /*
                 * The exact sequence expected by certain pre-ATA4 drives is:
                 * SRST RESET
                 * IDENTIFY
                 * INITIALIZE DEVICE PARAMETERS
                 * anything else..
                 * Some drives were very specific about that exact sequence.
                 */
                if (ata_id_major_version(id) < 4 || !ata_id_has_lba(id)) {
                        err_mask = ata_dev_init_params(dev, id[3], id[6]);
                        if (err_mask) {
                                rc = -EIO;
                                reason = "INIT_DEV_PARAMS failed";
                                goto err_out;
                        }

                        /* current CHS translation info (id[53-58]) might be
                         * changed. reread the identify device info.
                         */
                        flags &= ~ATA_READID_POSTRESET;
                        goto retry;
                }
        }

        *p_class = class;

        return 0;

 err_out:
        if (ata_msg_warn(ap))
                ata_dev_printk(dev, KERN_WARNING, "failed to IDENTIFY "
                               "(%s, err_mask=0x%x)\n", reason, err_mask);
        return rc;
}

static inline u8 ata_dev_knobble(struct ata_device *dev)
{
        return ((dev->ap->cbl == ATA_CBL_SATA) && (!ata_id_is_sata(dev->id)));
}

static void ata_dev_config_ncq(struct ata_device *dev,
                               char *desc, size_t desc_sz)
{
        struct ata_port *ap = dev->ap;
        int hdepth = 0, ddepth = ata_id_queue_depth(dev->id);

        if (!ata_id_has_ncq(dev->id)) {
                desc[0] = '\0';
                return;
        }
        if (ata_device_blacklisted(dev) & ATA_HORKAGE_NONCQ) {
                snprintf(desc, desc_sz, "NCQ (not used)");
                return;
        }
        if (ap->flags & ATA_FLAG_NCQ) {
                hdepth = min(ap->scsi_host->can_queue, ATA_MAX_QUEUE - 1);
                dev->flags |= ATA_DFLAG_NCQ;
        }

        if (hdepth >= ddepth)
                snprintf(desc, desc_sz, "NCQ (depth %d)", ddepth);
        else
                snprintf(desc, desc_sz, "NCQ (depth %d/%d)", hdepth, ddepth);
}

static void ata_set_port_max_cmd_len(struct ata_port *ap)
{
        int i;

        if (ap->scsi_host) {
                unsigned int len = 0;

                for (i = 0; i < ATA_MAX_DEVICES; i++)
                        len = max(len, ap->device[i].cdb_len);

                ap->scsi_host->max_cmd_len = len;
        }
}

/**
 *      ata_dev_configure - Configure the specified ATA/ATAPI device
 *      @dev: Target device to configure
 *
 *      Configure @dev according to @dev->id.  Generic and low-level
 *      driver specific fixups are also applied.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep)
 *
 *      RETURNS:
 *      0 on success, -errno otherwise
 */
int ata_dev_configure(struct ata_device *dev)
{
        struct ata_port *ap = dev->ap;
        int print_info = ap->eh_context.i.flags & ATA_EHI_PRINTINFO;
        const u16 *id = dev->id;
        unsigned int xfer_mask;
        char revbuf[7];         /* XYZ-99\0 */
        int rc;

        if (!ata_dev_enabled(dev) && ata_msg_info(ap)) {
                ata_dev_printk(dev, KERN_INFO,
                               "%s: ENTER/EXIT (host %u, dev %u) -- nodev\n",
                               __FUNCTION__, ap->id, dev->devno);
                return 0;
        }

        if (ata_msg_probe(ap))
                ata_dev_printk(dev, KERN_DEBUG, "%s: ENTER, host %u, dev %u\n",
                               __FUNCTION__, ap->id, dev->devno);

        /* print device capabilities */
        if (ata_msg_probe(ap))
                ata_dev_printk(dev, KERN_DEBUG,
                               "%s: cfg 49:%04x 82:%04x 83:%04x 84:%04x "
                               "85:%04x 86:%04x 87:%04x 88:%04x\n",
                               __FUNCTION__,
                               id[49], id[82], id[83], id[84],
                               id[85], id[86], id[87], id[88]);

        /* initialize to-be-configured parameters */
        dev->flags &= ~ATA_DFLAG_CFG_MASK;
        dev->max_sectors = 0;
        dev->cdb_len = 0;
        dev->n_sectors = 0;
        dev->cylinders = 0;
        dev->heads = 0;
        dev->sectors = 0;

        /*
         * common ATA, ATAPI feature tests
         */

        /* find max transfer mode; for printk only */
        xfer_mask = ata_id_xfermask(id);

        if (ata_msg_probe(ap))
                ata_dump_id(id);

        /* ATA-specific feature tests */
        if (dev->class == ATA_DEV_ATA) {
                if (ata_id_is_cfa(id)) {
                        if (id[162] & 1) /* CPRM may make this media unusable */
                                ata_dev_printk(dev, KERN_WARNING, "ata%u: device %u  supports DRM functions and may not be fully accessable.\n",
                                        ap->id, dev->devno);
                        snprintf(revbuf, 7, "CFA");
                }
                else
                        snprintf(revbuf, 7, "ATA-%d",  ata_id_major_version(id));

                dev->n_sectors = ata_id_n_sectors(id);

                if (ata_id_has_lba(id)) {
                        const char *lba_desc;
                        char ncq_desc[20];

                        lba_desc = "LBA";
                        dev->flags |= ATA_DFLAG_LBA;
                        if (ata_id_has_lba48(id)) {
                                dev->flags |= ATA_DFLAG_LBA48;
                                lba_desc = "LBA48";

                                if (dev->n_sectors >= (1UL << 28) &&
                                    ata_id_has_flush_ext(id))
                                        dev->flags |= ATA_DFLAG_FLUSH_EXT;
                        }

                        /* config NCQ */
                        ata_dev_config_ncq(dev, ncq_desc, sizeof(ncq_desc));

                        /* print device info to dmesg */
                        if (ata_msg_drv(ap) && print_info)
                                ata_dev_printk(dev, KERN_INFO, "%s, "
                                        "max %s, %Lu sectors: %s %s\n",
                                        revbuf,
                                        ata_mode_string(xfer_mask),
                                        (unsigned long long)dev->n_sectors,
                                        lba_desc, ncq_desc);
                } else {
                        /* CHS */

                        /* Default translation */
                        dev->cylinders  = id[1];
                        dev->heads      = id[3];
                        dev->sectors    = id[6];

                        if (ata_id_current_chs_valid(id)) {
                                /* Current CHS translation is valid. */
                                dev->cylinders = id[54];
                                dev->heads     = id[55];
                                dev->sectors   = id[56];
                        }

                        /* print device info to dmesg */
                        if (ata_msg_drv(ap) && print_info)
                                ata_dev_printk(dev, KERN_INFO, "%s, "
                                        "max %s, %Lu sectors: CHS %u/%u/%u\n",
                                        revbuf,
                                        ata_mode_string(xfer_mask),
                                        (unsigned long long)dev->n_sectors,
                                        dev->cylinders, dev->heads,
                                        dev->sectors);
                }

                if (dev->id[59] & 0x100) {
                        dev->multi_count = dev->id[59] & 0xff;
                        if (ata_msg_drv(ap) && print_info)
                                ata_dev_printk(dev, KERN_INFO,
                                        "ata%u: dev %u multi count %u\n",
                                        ap->id, dev->devno, dev->multi_count);
                }

                dev->cdb_len = 16;
        }

        /* ATAPI-specific feature tests */
        else if (dev->class == ATA_DEV_ATAPI) {
                char *cdb_intr_string = "";

                rc = atapi_cdb_len(id);
                if ((rc < 12) || (rc > ATAPI_CDB_LEN)) {
                        if (ata_msg_warn(ap))
                                ata_dev_printk(dev, KERN_WARNING,
                                               "unsupported CDB len\n");
                        rc = -EINVAL;
                        goto err_out_nosup;
                }
                dev->cdb_len = (unsigned int) rc;

                if (ata_id_cdb_intr(dev->id)) {
                        dev->flags |= ATA_DFLAG_CDB_INTR;
                        cdb_intr_string = ", CDB intr";
                }

                /* print device info to dmesg */
                if (ata_msg_drv(ap) && print_info)
                        ata_dev_printk(dev, KERN_INFO, "ATAPI, max %s%s\n",
                                       ata_mode_string(xfer_mask),
                                       cdb_intr_string);
        }

        /* determine max_sectors */
        dev->max_sectors = ATA_MAX_SECTORS;
        if (dev->flags & ATA_DFLAG_LBA48)
                dev->max_sectors = ATA_MAX_SECTORS_LBA48;

        if (dev->horkage & ATA_HORKAGE_DIAGNOSTIC) {
                /* Let the user know. We don't want to disallow opens for
                   rescue purposes, or in case the vendor is just a blithering
                   idiot */
                if (print_info) {
                        ata_dev_printk(dev, KERN_WARNING,
"Drive reports diagnostics failure. This may indicate a drive\n");
                        ata_dev_printk(dev, KERN_WARNING,
"fault or invalid emulation. Contact drive vendor for information.\n");
                }
        }

        ata_set_port_max_cmd_len(ap);

        /* limit bridge transfers to udma5, 200 sectors */
        if (ata_dev_knobble(dev)) {
                if (ata_msg_drv(ap) && print_info)
                        ata_dev_printk(dev, KERN_INFO,
                                       "applying bridge limits\n");
                dev->udma_mask &= ATA_UDMA5;
                dev->max_sectors = ATA_MAX_SECTORS;
        }

        if (ap->ops->dev_config)
                ap->ops->dev_config(ap, dev);

        if (ata_msg_probe(ap))
                ata_dev_printk(dev, KERN_DEBUG, "%s: EXIT, drv_stat = 0x%x\n",
                        __FUNCTION__, ata_chk_status(ap));
        return 0;

err_out_nosup:
        if (ata_msg_probe(ap))
                ata_dev_printk(dev, KERN_DEBUG,
                               "%s: EXIT, err\n", __FUNCTION__);
        return rc;
}

/**
 *      ata_bus_probe - Reset and probe ATA bus
 *      @ap: Bus to probe
 *
 *      Master ATA bus probing function.  Initiates a hardware-dependent
 *      bus reset, then attempts to identify any devices found on
 *      the bus.
 *
 *      LOCKING:
 *      PCI/etc. bus probe sem.
 *
 *      RETURNS:
 *      Zero on success, negative errno otherwise.
 */

int ata_bus_probe(struct ata_port *ap)
{
        unsigned int classes[ATA_MAX_DEVICES];
        int tries[ATA_MAX_DEVICES];
        int i, rc, down_xfermask;
        struct ata_device *dev;

        ata_port_probe(ap);

        for (i = 0; i < ATA_MAX_DEVICES; i++)
                tries[i] = ATA_PROBE_MAX_TRIES;

 retry:
        down_xfermask = 0;

        /* reset and determine device classes */
        ap->ops->phy_reset(ap);

        for (i = 0; i < ATA_MAX_DEVICES; i++) {
                dev = &ap->device[i];

                if (!(ap->flags & ATA_FLAG_DISABLED) &&
                    dev->class != ATA_DEV_UNKNOWN)
                        classes[dev->devno] = dev->class;
                else
                        classes[dev->devno] = ATA_DEV_NONE;

                dev->class = ATA_DEV_UNKNOWN;
        }

        ata_port_probe(ap);

        /* after the reset the device state is PIO 0 and the controller
           state is undefined. Record the mode */

        for (i = 0; i < ATA_MAX_DEVICES; i++)
                ap->device[i].pio_mode = XFER_PIO_0;

        /* read IDENTIFY page and configure devices */
        for (i = 0; i < ATA_MAX_DEVICES; i++) {
                dev = &ap->device[i];

                if (tries[i])
                        dev->class = classes[i];

                if (!ata_dev_enabled(dev))
                        continue;

                rc = ata_dev_read_id(dev, &dev->class, ATA_READID_POSTRESET,
                                     dev->id);
                if (rc)
                        goto fail;

                ap->eh_context.i.flags |= ATA_EHI_PRINTINFO;
                rc = ata_dev_configure(dev);
                ap->eh_context.i.flags &= ~ATA_EHI_PRINTINFO;
                if (rc)
                        goto fail;
        }

        /* configure transfer mode */
        rc = ata_set_mode(ap, &dev);
        if (rc) {
                down_xfermask = 1;
                goto fail;
        }

        for (i = 0; i < ATA_MAX_DEVICES; i++)
                if (ata_dev_enabled(&ap->device[i]))
                        return 0;

        /* no device present, disable port */
        ata_port_disable(ap);
        ap->ops->port_disable(ap);
        return -ENODEV;

 fail:
        switch (rc) {
        case -EINVAL:
        case -ENODEV:
                tries[dev->devno] = 0;
                break;
        case -EIO:
                sata_down_spd_limit(ap);
                /* fall through */
        default:
                tries[dev->devno]--;
                if (down_xfermask &&
                    ata_down_xfermask_limit(dev, tries[dev->devno] == 1))
                        tries[dev->devno] = 0;
        }

        if (!tries[dev->devno]) {
                ata_down_xfermask_limit(dev, 1);
                ata_dev_disable(dev);
        }

        goto retry;
}

/**
 *      ata_port_probe - Mark port as enabled
 *      @ap: Port for which we indicate enablement
 *
 *      Modify @ap data structure such that the system
 *      thinks that the entire port is enabled.
 *
 *      LOCKING: host lock, or some other form of
 *      serialization.
 */

void ata_port_probe(struct ata_port *ap)
{
        ap->flags &= ~ATA_FLAG_DISABLED;
}

/**
 *      sata_print_link_status - Print SATA link status
 *      @ap: SATA port to printk link status about
 *
 *      This function prints link speed and status of a SATA link.
 *
 *      LOCKING:
 *      None.
 */
static void sata_print_link_status(struct ata_port *ap)
{
        u32 sstatus, scontrol, tmp;

        if (sata_scr_read(ap, SCR_STATUS, &sstatus))
                return;
        sata_scr_read(ap, SCR_CONTROL, &scontrol);

        if (ata_port_online(ap)) {
                tmp = (sstatus >> 4) & 0xf;
                ata_port_printk(ap, KERN_INFO,
                                "SATA link up %s (SStatus %X SControl %X)\n",
                                sata_spd_string(tmp), sstatus, scontrol);
        } else {
                ata_port_printk(ap, KERN_INFO,
                                "SATA link down (SStatus %X SControl %X)\n",
                                sstatus, scontrol);
        }
}

/**
 *      __sata_phy_reset - Wake/reset a low-level SATA PHY
 *      @ap: SATA port associated with target SATA PHY.
 *
 *      This function issues commands to standard SATA Sxxx
 *      PHY registers, to wake up the phy (and device), and
 *      clear any reset condition.
 *
 *      LOCKING:
 *      PCI/etc. bus probe sem.
 *
 */
void __sata_phy_reset(struct ata_port *ap)
{
        u32 sstatus;
        unsigned long timeout = jiffies + (HZ * 5);

        if (ap->flags & ATA_FLAG_SATA_RESET) {
                /* issue phy wake/reset */
                sata_scr_write_flush(ap, SCR_CONTROL, 0x301);
                /* Couldn't find anything in SATA I/II specs, but
                 * AHCI-1.1 10.4.2 says at least 1 ms. */
                mdelay(1);
        }
        /* phy wake/clear reset */
        sata_scr_write_flush(ap, SCR_CONTROL, 0x300);

        /* wait for phy to become ready, if necessary */
        do {
                msleep(200);
                sata_scr_read(ap, SCR_STATUS, &sstatus);
                if ((sstatus & 0xf) != 1)
                        break;
        } while (time_before(jiffies, timeout));

        /* print link status */
        sata_print_link_status(ap);

        /* TODO: phy layer with polling, timeouts, etc. */
        if (!ata_port_offline(ap))
                ata_port_probe(ap);
        else
                ata_port_disable(ap);

        if (ap->flags & ATA_FLAG_DISABLED)
                return;

        if (ata_busy_sleep(ap, ATA_TMOUT_BOOT_QUICK, ATA_TMOUT_BOOT)) {
                ata_port_disable(ap);
                return;
        }

        ap->cbl = ATA_CBL_SATA;
}

/**
 *      sata_phy_reset - Reset SATA bus.
 *      @ap: SATA port associated with target SATA PHY.
 *
 *      This function resets the SATA bus, and then probes
 *      the bus for devices.
 *
 *      LOCKING:
 *      PCI/etc. bus probe sem.
 *
 */
void sata_phy_reset(struct ata_port *ap)
{
        __sata_phy_reset(ap);
        if (ap->flags & ATA_FLAG_DISABLED)
                return;
        ata_bus_reset(ap);
}

/**
 *      ata_dev_pair            -       return other device on cable
 *      @adev: device
 *
 *      Obtain the other device on the same cable, or if none is
 *      present NULL is returned
 */

struct ata_device *ata_dev_pair(struct ata_device *adev)
{
        struct ata_port *ap = adev->ap;
        struct ata_device *pair = &ap->device[1 - adev->devno];
        if (!ata_dev_enabled(pair))
                return NULL;
        return pair;
}

/**
 *      ata_port_disable - Disable port.
 *      @ap: Port to be disabled.
 *
 *      Modify @ap data structure such that the system
 *      thinks that the entire port is disabled, and should
 *      never attempt to probe or communicate with devices
 *      on this port.
 *
 *      LOCKING: host lock, or some other form of
 *      serialization.
 */

void ata_port_disable(struct ata_port *ap)
{
        ap->device[0].class = ATA_DEV_NONE;
        ap->device[1].class = ATA_DEV_NONE;
        ap->flags |= ATA_FLAG_DISABLED;
}

/**
 *      sata_down_spd_limit - adjust SATA spd limit downward
 *      @ap: Port to adjust SATA spd limit for
 *
 *      Adjust SATA spd limit of @ap downward.  Note that this
 *      function only adjusts the limit.  The change must be applied
 *      using sata_set_spd().
 *
 *      LOCKING:
 *      Inherited from caller.
 *
 *      RETURNS:
 *      0 on success, negative errno on failure
 */
int sata_down_spd_limit(struct ata_port *ap)
{
        u32 sstatus, spd, mask;
        int rc, highbit;

        rc = sata_scr_read(ap, SCR_STATUS, &sstatus);
        if (rc)
                return rc;

        mask = ap->sata_spd_limit;
        if (mask <= 1)
                return -EINVAL;
        highbit = fls(mask) - 1;
        mask &= ~(1 << highbit);

        spd = (sstatus >> 4) & 0xf;
        if (spd <= 1)
                return -EINVAL;
        spd--;
        mask &= (1 << spd) - 1;
        if (!mask)
                return -EINVAL;

        ap->sata_spd_limit = mask;

        ata_port_printk(ap, KERN_WARNING, "limiting SATA link speed to %s\n",
                        sata_spd_string(fls(mask)));

        return 0;
}

static int __sata_set_spd_needed(struct ata_port *ap, u32 *scontrol)
{
        u32 spd, limit;

        if (ap->sata_spd_limit == UINT_MAX)
                limit = 0;
        else
                limit = fls(ap->sata_spd_limit);

        spd = (*scontrol >> 4) & 0xf;
        *scontrol = (*scontrol & ~0xf0) | ((limit & 0xf) << 4);

        return spd != limit;
}

/**
 *      sata_set_spd_needed - is SATA spd configuration needed
 *      @ap: Port in question
 *
 *      Test whether the spd limit in SControl matches
 *      @ap->sata_spd_limit.  This function is used to determine
 *      whether hardreset is necessary to apply SATA spd
 *      configuration.
 *
 *      LOCKING:
 *      Inherited from caller.
 *
 *      RETURNS:
 *      1 if SATA spd configuration is needed, 0 otherwise.
 */
int sata_set_spd_needed(struct ata_port *ap)
{
        u32 scontrol;

        if (sata_scr_read(ap, SCR_CONTROL, &scontrol))
                return 0;

        return __sata_set_spd_needed(ap, &scontrol);
}

/**
 *      sata_set_spd - set SATA spd according to spd limit
 *      @ap: Port to set SATA spd for
 *
 *      Set SATA spd of @ap according to sata_spd_limit.
 *
 *      LOCKING:
 *      Inherited from caller.
 *
 *      RETURNS:
 *      0 if spd doesn't need to be changed, 1 if spd has been
 *      changed.  Negative errno if SCR registers are inaccessible.
 */
int sata_set_spd(struct ata_port *ap)
{
        u32 scontrol;
        int rc;

        if ((rc = sata_scr_read(ap, SCR_CONTROL, &scontrol)))
                return rc;

        if (!__sata_set_spd_needed(ap, &scontrol))
                return 0;

        if ((rc = sata_scr_write(ap, SCR_CONTROL, scontrol)))
                return rc;

        return 1;
}

/*
 * This mode timing computation functionality is ported over from
 * drivers/ide/ide-timing.h and was originally written by Vojtech Pavlik
 */
/*
 * PIO 0-4, MWDMA 0-2 and UDMA 0-6 timings (in nanoseconds).
 * These were taken from ATA/ATAPI-6 standard, rev 0a, except
 * for UDMA6, which is currently supported only by Maxtor drives.
 *
 * For PIO 5/6 MWDMA 3/4 see the CFA specification 3.0.
 */

static const struct ata_timing ata_timing[] = {

        { XFER_UDMA_6,     0,   0,   0,   0,   0,   0,   0,  15 },
        { XFER_UDMA_5,     0,   0,   0,   0,   0,   0,   0,  20 },
        { XFER_UDMA_4,     0,   0,   0,   0,   0,   0,   0,  30 },
        { XFER_UDMA_3,     0,   0,   0,   0,   0,   0,   0,  45 },

        { XFER_MW_DMA_4,  25,   0,   0,   0,  55,  20,  80,   0 },
        { XFER_MW_DMA_3,  25,   0,   0,   0,  65,  25, 100,   0 },
        { XFER_UDMA_2,     0,   0,   0,   0,   0,   0,   0,  60 },
        { XFER_UDMA_1,     0,   0,   0,   0,   0,   0,   0,  80 },
        { XFER_UDMA_0,     0,   0,   0,   0,   0,   0,   0, 120 },

/*      { XFER_UDMA_SLOW,  0,   0,   0,   0,   0,   0,   0, 150 }, */

        { XFER_MW_DMA_2,  25,   0,   0,   0,  70,  25, 120,   0 },
        { XFER_MW_DMA_1,  45,   0,   0,   0,  80,  50, 150,   0 },
        { XFER_MW_DMA_0,  60,   0,   0,   0, 215, 215, 480,   0 },

        { XFER_SW_DMA_2,  60,   0,   0,   0, 120, 120, 240,   0 },
        { XFER_SW_DMA_1,  90,   0,   0,   0, 240, 240, 480,   0 },
        { XFER_SW_DMA_0, 120,   0,   0,   0, 480, 480, 960,   0 },

        { XFER_PIO_6,     10,  55,  20,  80,  55,  20,  80,   0 },
        { XFER_PIO_5,     15,  65,  25, 100,  65,  25, 100,   0 },
        { XFER_PIO_4,     25,  70,  25, 120,  70,  25, 120,   0 },
        { XFER_PIO_3,     30,  80,  70, 180,  80,  70, 180,   0 },

        { XFER_PIO_2,     30, 290,  40, 330, 100,  90, 240,   0 },
        { XFER_PIO_1,     50, 290,  93, 383, 125, 100, 383,   0 },
        { XFER_PIO_0,     70, 290, 240, 600, 165, 150, 600,   0 },

/*      { XFER_PIO_SLOW, 120, 290, 240, 960, 290, 240, 960,   0 }, */

        { 0xFF }
};

#define ENOUGH(v,unit)          (((v)-1)/(unit)+1)
#define EZ(v,unit)              ((v)?ENOUGH(v,unit):0)

static void ata_timing_quantize(const struct ata_timing *t, struct ata_timing *q, int T, int UT)
{
        q->setup   = EZ(t->setup   * 1000,  T);
        q->act8b   = EZ(t->act8b   * 1000,  T);
        q->rec8b   = EZ(t->rec8b   * 1000,  T);
        q->cyc8b   = EZ(t->cyc8b   * 1000,  T);
        q->active  = EZ(t->active  * 1000,  T);
        q->recover = EZ(t->recover * 1000,  T);
        q->cycle   = EZ(t->cycle   * 1000,  T);
        q->udma    = EZ(t->udma    * 1000, UT);
}

void ata_timing_merge(const struct ata_timing *a, const struct ata_timing *b,
                      struct ata_timing *m, unsigned int what)
{
        if (what & ATA_TIMING_SETUP  ) m->setup   = max(a->setup,   b->setup);
        if (what & ATA_TIMING_ACT8B  ) m->act8b   = max(a->act8b,   b->act8b);
        if (what & ATA_TIMING_REC8B  ) m->rec8b   = max(a->rec8b,   b->rec8b);
        if (what & ATA_TIMING_CYC8B  ) m->cyc8b   = max(a->cyc8b,   b->cyc8b);
        if (what & ATA_TIMING_ACTIVE ) m->active  = max(a->active,  b->active);
        if (what & ATA_TIMING_RECOVER) m->recover = max(a->recover, b->recover);
        if (what & ATA_TIMING_CYCLE  ) m->cycle   = max(a->cycle,   b->cycle);
        if (what & ATA_TIMING_UDMA   ) m->udma    = max(a->udma,    b->udma);
}

static const struct ata_timing* ata_timing_find_mode(unsigned short speed)
{
        const struct ata_timing *t;

        for (t = ata_timing; t->mode != speed; t++)
                if (t->mode == 0xFF)
                        return NULL;
        return t;
}

int ata_timing_compute(struct ata_device *adev, unsigned short speed,
                       struct ata_timing *t, int T, int UT)
{
        const struct ata_timing *s;
        struct ata_timing p;

        /*
         * Find the mode.
         */

        if (!(s = ata_timing_find_mode(speed)))
                return -EINVAL;

        memcpy(t, s, sizeof(*s));

        /*
         * If the drive is an EIDE drive, it can tell us it needs extended
         * PIO/MW_DMA cycle timing.
         */

        if (adev->id[ATA_ID_FIELD_VALID] & 2) { /* EIDE drive */
                memset(&p, 0, sizeof(p));
                if(speed >= XFER_PIO_0 && speed <= XFER_SW_DMA_0) {
                        if (speed <= XFER_PIO_2) p.cycle = p.cyc8b = adev->id[ATA_ID_EIDE_PIO];
                                            else p.cycle = p.cyc8b = adev->id[ATA_ID_EIDE_PIO_IORDY];
                } else if(speed >= XFER_MW_DMA_0 && speed <= XFER_MW_DMA_2) {
                        p.cycle = adev->id[ATA_ID_EIDE_DMA_MIN];
                }
                ata_timing_merge(&p, t, t, ATA_TIMING_CYCLE | ATA_TIMING_CYC8B);
        }

        /*
         * Convert the timing to bus clock counts.
         */

        ata_timing_quantize(t, t, T, UT);

        /*
         * Even in DMA/UDMA modes we still use PIO access for IDENTIFY,
         * S.M.A.R.T * and some other commands. We have to ensure that the
         * DMA cycle timing is slower/equal than the fastest PIO timing.
         */

        if (speed > XFER_PIO_6) {
                ata_timing_compute(adev, adev->pio_mode, &p, T, UT);
                ata_timing_merge(&p, t, t, ATA_TIMING_ALL);
        }

        /*
         * Lengthen active & recovery time so that cycle time is correct.
         */

        if (t->act8b + t->rec8b < t->cyc8b) {
                t->act8b += (t->cyc8b - (t->act8b + t->rec8b)) / 2;
                t->rec8b = t->cyc8b - t->act8b;
        }

        if (t->active + t->recover < t->cycle) {
                t->active += (t->cycle - (t->active + t->recover)) / 2;
                t->recover = t->cycle - t->active;
        }

        return 0;
}

/**
 *      ata_down_xfermask_limit - adjust dev xfer masks downward
 *      @dev: Device to adjust xfer masks
 *      @force_pio0: Force PIO0
 *
 *      Adjust xfer masks of @dev downward.  Note that this function
 *      does not apply the change.  Invoking ata_set_mode() afterwards
 *      will apply the limit.
 *
 *      LOCKING:
 *      Inherited from caller.
 *
 *      RETURNS:
 *      0 on success, negative errno on failure
 */
int ata_down_xfermask_limit(struct ata_device *dev, int force_pio0)
{
        unsigned long xfer_mask;
        int highbit;

        xfer_mask = ata_pack_xfermask(dev->pio_mask, dev->mwdma_mask,
                                      dev->udma_mask);

        if (!xfer_mask)
                goto fail;
        /* don't gear down to MWDMA from UDMA, go directly to PIO */
        if (xfer_mask & ATA_MASK_UDMA)
                xfer_mask &= ~ATA_MASK_MWDMA;

        highbit = fls(xfer_mask) - 1;
        xfer_mask &= ~(1 << highbit);
        if (force_pio0)
                xfer_mask &= 1 << ATA_SHIFT_PIO;
        if (!xfer_mask)
                goto fail;

        ata_unpack_xfermask(xfer_mask, &dev->pio_mask, &dev->mwdma_mask,
                            &dev->udma_mask);

        ata_dev_printk(dev, KERN_WARNING, "limiting speed to %s\n",
                       ata_mode_string(xfer_mask));

        return 0;

 fail:
        return -EINVAL;
}

static int ata_dev_set_mode(struct ata_device *dev)
{
        struct ata_eh_context *ehc = &dev->ap->eh_context;
        unsigned int err_mask;
        int rc;

        dev->flags &= ~ATA_DFLAG_PIO;
        if (dev->xfer_shift == ATA_SHIFT_PIO)
                dev->flags |= ATA_DFLAG_PIO;

        err_mask = ata_dev_set_xfermode(dev);
        if (err_mask) {
                ata_dev_printk(dev, KERN_ERR, "failed to set xfermode "
                               "(err_mask=0x%x)\n", err_mask);
                return -EIO;
        }

        ehc->i.flags |= ATA_EHI_POST_SETMODE;
        rc = ata_dev_revalidate(dev, 0);
        ehc->i.flags &= ~ATA_EHI_POST_SETMODE;
        if (rc)
                return rc;

        DPRINTK("xfer_shift=%u, xfer_mode=0x%x\n",
                dev->xfer_shift, (int)dev->xfer_mode);

        ata_dev_printk(dev, KERN_INFO, "configured for %s\n",
                       ata_mode_string(ata_xfer_mode2mask(dev->xfer_mode)));
        return 0;
}

/**
 *      ata_set_mode - Program timings and issue SET FEATURES - XFER
 *      @ap: port on which timings will be programmed
 *      @r_failed_dev: out paramter for failed device
 *
 *      Set ATA device disk transfer mode (PIO3, UDMA6, etc.).  If
 *      ata_set_mode() fails, pointer to the failing device is
 *      returned in @r_failed_dev.
 *
 *      LOCKING:
 *      PCI/etc. bus probe sem.
 *
 *      RETURNS:
 *      0 on success, negative errno otherwise
 */
int ata_set_mode(struct ata_port *ap, struct ata_device **r_failed_dev)
{
        struct ata_device *dev;
        int i, rc = 0, used_dma = 0, found = 0;

        /* has private set_mode? */
        if (ap->ops->set_mode)
                return ap->ops->set_mode(ap, r_failed_dev);

        /* step 1: calculate xfer_mask */
        for (i = 0; i < ATA_MAX_DEVICES; i++) {
                unsigned int pio_mask, dma_mask;

                dev = &ap->device[i];

                if (!ata_dev_enabled(dev))
                        continue;

                ata_dev_xfermask(dev);

                pio_mask = ata_pack_xfermask(dev->pio_mask, 0, 0);
                dma_mask = ata_pack_xfermask(0, dev->mwdma_mask, dev->udma_mask);
                dev->pio_mode = ata_xfer_mask2mode(pio_mask);
                dev->dma_mode = ata_xfer_mask2mode(dma_mask);

                found = 1;
                if (dev->dma_mode)
                        used_dma = 1;
        }
        if (!found)
                goto out;

        /* step 2: always set host PIO timings */
        for (i = 0; i < ATA_MAX_DEVICES; i++) {
                dev = &ap->device[i];
                if (!ata_dev_enabled(dev))
                        continue;

                if (!dev->pio_mode) {
                        ata_dev_printk(dev, KERN_WARNING, "no PIO support\n");
                        rc = -EINVAL;
                        goto out;
                }

                dev->xfer_mode = dev->pio_mode;
                dev->xfer_shift = ATA_SHIFT_PIO;
                if (ap->ops->set_piomode)
                        ap->ops->set_piomode(ap, dev);
        }

        /* step 3: set host DMA timings */
        for (i = 0; i < ATA_MAX_DEVICES; i++) {
                dev = &ap->device[i];

                if (!ata_dev_enabled(dev) || !dev->dma_mode)
                        continue;

                dev->xfer_mode = dev->dma_mode;
                dev->xfer_shift = ata_xfer_mode2shift(dev->dma_mode);
                if (ap->ops->set_dmamode)
                        ap->ops->set_dmamode(ap, dev);
        }

        /* step 4: update devices' xfer mode */
        for (i = 0; i < ATA_MAX_DEVICES; i++) {
                dev = &ap->device[i];

                /* don't udpate suspended devices' xfer mode */
                if (!ata_dev_ready(dev))
                        continue;

                rc = ata_dev_set_mode(dev);
                if (rc)
                        goto out;
        }

        /* Record simplex status. If we selected DMA then the other
         * host channels are not permitted to do so.
         */
        if (used_dma && (ap->host->flags & ATA_HOST_SIMPLEX))
                ap->host->simplex_claimed = 1;

        /* step5: chip specific finalisation */
        if (ap->ops->post_set_mode)
                ap->ops->post_set_mode(ap);

 out:
        if (rc)
                *r_failed_dev = dev;
        return rc;
}

/**
 *      ata_tf_to_host - issue ATA taskfile to host controller
 *      @ap: port to which command is being issued
 *      @tf: ATA taskfile register set
 *
 *      Issues ATA taskfile register set to ATA host controller,
 *      with proper synchronization with interrupt handler and
 *      other threads.
 *
 *      LOCKING:
 *      spin_lock_irqsave(host lock)
 */

static inline void ata_tf_to_host(struct ata_port *ap,
                                  const struct ata_taskfile *tf)
{
        ap->ops->tf_load(ap, tf);
        ap->ops->exec_command(ap, tf);
}

/**
 *      ata_busy_sleep - sleep until BSY clears, or timeout
 *      @ap: port containing status register to be polled
 *      @tmout_pat: impatience timeout
 *      @tmout: overall timeout
 *
 *      Sleep until ATA Status register bit BSY clears,
 *      or a timeout occurs.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep).
 *
 *      RETURNS:
 *      0 on success, -errno otherwise.
 */
int ata_busy_sleep(struct ata_port *ap,
                   unsigned long tmout_pat, unsigned long tmout)
{
        unsigned long timer_start, timeout;
        u8 status;

        status = ata_busy_wait(ap, ATA_BUSY, 300);
        timer_start = jiffies;
        timeout = timer_start + tmout_pat;
        while (status != 0xff && (status & ATA_BUSY) &&
               time_before(jiffies, timeout)) {
                msleep(50);
                status = ata_busy_wait(ap, ATA_BUSY, 3);
        }

        if (status != 0xff && (status & ATA_BUSY))
                ata_port_printk(ap, KERN_WARNING,
                                "port is slow to respond, please be patient "
                                "(Status 0x%x)\n", status);

        timeout = timer_start + tmout;
        while (status != 0xff && (status & ATA_BUSY) &&
               time_before(jiffies, timeout)) {
                msleep(50);
                status = ata_chk_status(ap);
        }

        if (status == 0xff)
                return -ENODEV;

        if (status & ATA_BUSY) {
                ata_port_printk(ap, KERN_ERR, "port failed to respond "
                                "(%lu secs, Status 0x%x)\n",
                                tmout / HZ, status);
                return -EBUSY;
        }

        return 0;
}

static void ata_bus_post_reset(struct ata_port *ap, unsigned int devmask)
{
        struct ata_ioports *ioaddr = &ap->ioaddr;
        unsigned int dev0 = devmask & (1 << 0);
        unsigned int dev1 = devmask & (1 << 1);
        unsigned long timeout;

        /* if device 0 was found in ata_devchk, wait for its
         * BSY bit to clear
         */
        if (dev0)
                ata_busy_sleep(ap, ATA_TMOUT_BOOT_QUICK, ATA_TMOUT_BOOT);

        /* if device 1 was found in ata_devchk, wait for
         * register access, then wait for BSY to clear
         */
        timeout = jiffies + ATA_TMOUT_BOOT;
        while (dev1) {
                u8 nsect, lbal;

                ap->ops->dev_select(ap, 1);
                if (ap->flags & ATA_FLAG_MMIO) {
                        nsect = readb((void __iomem *) ioaddr->nsect_addr);
                        lbal = readb((void __iomem *) ioaddr->lbal_addr);
                } else {
                        nsect = inb(ioaddr->nsect_addr);
                        lbal = inb(ioaddr->lbal_addr);
                }
                if ((nsect == 1) && (lbal == 1))
                        break;
                if (time_after(jiffies, timeout)) {
                        dev1 = 0;
                        break;
                }
                msleep(50);     /* give drive a breather */
        }
        if (dev1)
                ata_busy_sleep(ap, ATA_TMOUT_BOOT_QUICK, ATA_TMOUT_BOOT);

        /* is all this really necessary? */
        ap->ops->dev_select(ap, 0);
        if (dev1)
                ap->ops->dev_select(ap, 1);
        if (dev0)
                ap->ops->dev_select(ap, 0);
}

static unsigned int ata_bus_softreset(struct ata_port *ap,
                                      unsigned int devmask)
{
        struct ata_ioports *ioaddr = &ap->ioaddr;

        DPRINTK("ata%u: bus reset via SRST\n", ap->id);

        /* software reset.  causes dev0 to be selected */
        if (ap->flags & ATA_FLAG_MMIO) {
                writeb(ap->ctl, (void __iomem *) ioaddr->ctl_addr);
                udelay(20);     /* FIXME: flush */
                writeb(ap->ctl | ATA_SRST, (void __iomem *) ioaddr->ctl_addr);
                udelay(20);     /* FIXME: flush */
                writeb(ap->ctl, (void __iomem *) ioaddr->ctl_addr);
        } else {
                outb(ap->ctl, ioaddr->ctl_addr);
                udelay(10);
                outb(ap->ctl | ATA_SRST, ioaddr->ctl_addr);
                udelay(10);
                outb(ap->ctl, ioaddr->ctl_addr);
        }

        /* spec mandates ">= 2ms" before checking status.
         * We wait 150ms, because that was the magic delay used for
         * ATAPI devices in Hale Landis's ATADRVR, for the period of time
         * between when the ATA command register is written, and then
         * status is checked.  Because waiting for "a while" before
         * checking status is fine, post SRST, we perform this magic
         * delay here as well.
         *
         * Old drivers/ide uses the 2mS rule and then waits for ready
         */
        msleep(150);

        /* Before we perform post reset processing we want to see if
         * the bus shows 0xFF because the odd clown forgets the D7
         * pulldown resistor.
         */
        if (ata_check_status(ap) == 0xFF)
                return 0;

        ata_bus_post_reset(ap, devmask);

        return 0;
}

/**
 *      ata_bus_reset - reset host port and associated ATA channel
 *      @ap: port to reset
 *
 *      This is typically the first time we actually start issuing
 *      commands to the ATA channel.  We wait for BSY to clear, then
 *      issue EXECUTE DEVICE DIAGNOSTIC command, polling for its
 *      result.  Determine what devices, if any, are on the channel
 *      by looking at the device 0/1 error register.  Look at the signature
 *      stored in each device's taskfile registers, to determine if
 *      the device is ATA or ATAPI.
 *
 *      LOCKING:
 *      PCI/etc. bus probe sem.
 *      Obtains host lock.
 *
 *      SIDE EFFECTS:
 *      Sets ATA_FLAG_DISABLED if bus reset fails.
 */

void ata_bus_reset(struct ata_port *ap)
{
        struct ata_ioports *ioaddr = &ap->ioaddr;
        unsigned int slave_possible = ap->flags & ATA_FLAG_SLAVE_POSS;
        u8 err;
        unsigned int dev0, dev1 = 0, devmask = 0;

        DPRINTK("ENTER, host %u, port %u\n", ap->id, ap->port_no);

        /* determine if device 0/1 are present */
        if (ap->flags & ATA_FLAG_SATA_RESET)
                dev0 = 1;
        else {
                dev0 = ata_devchk(ap, 0);
                if (slave_possible)
                        dev1 = ata_devchk(ap, 1);
        }

        if (dev0)
                devmask |= (1 << 0);
        if (dev1)
                devmask |= (1 << 1);

        /* select device 0 again */
        ap->ops->dev_select(ap, 0);

        /* issue bus reset */
        if (ap->flags & ATA_FLAG_SRST)
                if (ata_bus_softreset(ap, devmask))
                        goto err_out;

        /*
         * determine by signature whether we have ATA or ATAPI devices
         */
        ap->device[0].class = ata_dev_try_classify(ap, 0, &err);
        if ((slave_possible) && (err != 0x81))
                ap->device[1].class = ata_dev_try_classify(ap, 1, &err);

        /* re-enable interrupts */
        if (ap->ioaddr.ctl_addr)        /* FIXME: hack. create a hook instead */
                ata_irq_on(ap);

        /* is double-select really necessary? */
        if (ap->device[1].class != ATA_DEV_NONE)
                ap->ops->dev_select(ap, 1);
        if (ap->device[0].class != ATA_DEV_NONE)
                ap->ops->dev_select(ap, 0);

        /* if no devices were detected, disable this port */
        if ((ap->device[0].class == ATA_DEV_NONE) &&
            (ap->device[1].class == ATA_DEV_NONE))
                goto err_out;

        if (ap->flags & (ATA_FLAG_SATA_RESET | ATA_FLAG_SRST)) {
                /* set up device control for ATA_FLAG_SATA_RESET */
                if (ap->flags & ATA_FLAG_MMIO)
                        writeb(ap->ctl, (void __iomem *) ioaddr->ctl_addr);
                else
                        outb(ap->ctl, ioaddr->ctl_addr);
        }

        DPRINTK("EXIT\n");
        return;

err_out:
        ata_port_printk(ap, KERN_ERR, "disabling port\n");
        ap->ops->port_disable(ap);

        DPRINTK("EXIT\n");
}

/**
 *      sata_phy_debounce - debounce SATA phy status
 *      @ap: ATA port to debounce SATA phy status for
 *      @params: timing parameters { interval, duratinon, timeout } in msec
 *
 *      Make sure SStatus of @ap reaches stable state, determined by
 *      holding the same value where DET is not 1 for @duration polled
 *      every @interval, before @timeout.  Timeout constraints the
 *      beginning of the stable state.  Because, after hot unplugging,
 *      DET gets stuck at 1 on some controllers, this functions waits
 *      until timeout then returns 0 if DET is stable at 1.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep)
 *
 *      RETURNS:
 *      0 on success, -errno on failure.
 */
int sata_phy_debounce(struct ata_port *ap, const unsigned long *params)
{
        unsigned long interval_msec = params[0];
        unsigned long duration = params[1] * HZ / 1000;
        unsigned long timeout = jiffies + params[2] * HZ / 1000;
        unsigned long last_jiffies;
        u32 last, cur;
        int rc;

        if ((rc = sata_scr_read(ap, SCR_STATUS, &cur)))
                return rc;
        cur &= 0xf;

        last = cur;
        last_jiffies = jiffies;

        while (1) {
                msleep(interval_msec);
                if ((rc = sata_scr_read(ap, SCR_STATUS, &cur)))
                        return rc;
                cur &= 0xf;

                /* DET stable? */
                if (cur == last) {
                        if (cur == 1 && time_before(jiffies, timeout))
                                continue;
                        if (time_after(jiffies, last_jiffies + duration))
                                return 0;
                        continue;
                }

                /* unstable, start over */
                last = cur;
                last_jiffies = jiffies;

                /* check timeout */
                if (time_after(jiffies, timeout))
                        return -EBUSY;
        }
}

/**
 *      sata_phy_resume - resume SATA phy
 *      @ap: ATA port to resume SATA phy for
 *      @params: timing parameters { interval, duratinon, timeout } in msec
 *
 *      Resume SATA phy of @ap and debounce it.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep)
 *
 *      RETURNS:
 *      0 on success, -errno on failure.
 */
int sata_phy_resume(struct ata_port *ap, const unsigned long *params)
{
        u32 scontrol;
        int rc;

        if ((rc = sata_scr_read(ap, SCR_CONTROL, &scontrol)))
                return rc;

        scontrol = (scontrol & 0x0f0) | 0x300;

        if ((rc = sata_scr_write(ap, SCR_CONTROL, scontrol)))
                return rc;

        /* Some PHYs react badly if SStatus is pounded immediately
         * after resuming.  Delay 200ms before debouncing.
         */
        msleep(200);

        return sata_phy_debounce(ap, params);
}

static void ata_wait_spinup(struct ata_port *ap)
{
        struct ata_eh_context *ehc = &ap->eh_context;
        unsigned long end, secs;
        int rc;

        /* first, debounce phy if SATA */
        if (ap->cbl == ATA_CBL_SATA) {
                rc = sata_phy_debounce(ap, sata_deb_timing_hotplug);

                /* if debounced successfully and offline, no need to wait */
                if ((rc == 0 || rc == -EOPNOTSUPP) && ata_port_offline(ap))
                        return;
        }

        /* okay, let's give the drive time to spin up */
        end = ehc->i.hotplug_timestamp + ATA_SPINUP_WAIT * HZ / 1000;
        secs = ((end - jiffies) + HZ - 1) / HZ;

        if (time_after(jiffies, end))
                return;

        if (secs > 5)
                ata_port_printk(ap, KERN_INFO, "waiting for device to spin up "
                                "(%lu secs)\n", secs);

        schedule_timeout_uninterruptible(end - jiffies);
}

/**
 *      ata_std_prereset - prepare for reset
 *      @ap: ATA port to be reset
 *
 *      @ap is about to be reset.  Initialize it.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep)
 *
 *      RETURNS:
 *      0 on success, -errno otherwise.
 */
int ata_std_prereset(struct ata_port *ap)
{
        struct ata_eh_context *ehc = &ap->eh_context;
        const unsigned long *timing = sata_ehc_deb_timing(ehc);
        int rc;

        /* handle link resume & hotplug spinup */
        if ((ehc->i.flags & ATA_EHI_RESUME_LINK) &&
            (ap->flags & ATA_FLAG_HRST_TO_RESUME))
                ehc->i.action |= ATA_EH_HARDRESET;

        if ((ehc->i.flags & ATA_EHI_HOTPLUGGED) &&
            (ap->flags & ATA_FLAG_SKIP_D2H_BSY))
                ata_wait_spinup(ap);

        /* if we're about to do hardreset, nothing more to do */
        if (ehc->i.action & ATA_EH_HARDRESET)
                return 0;

        /* if SATA, resume phy */
        if (ap->cbl == ATA_CBL_SATA) {
                rc = sata_phy_resume(ap, timing);
                if (rc && rc != -EOPNOTSUPP) {
                        /* phy resume failed */
                        ata_port_printk(ap, KERN_WARNING, "failed to resume "
                                        "link for reset (errno=%d)\n", rc);
                        return rc;
                }
        }

        /* Wait for !BSY if the controller can wait for the first D2H
         * Reg FIS and we don't know that no device is attached.
         */
        if (!(ap->flags & ATA_FLAG_SKIP_D2H_BSY) && !ata_port_offline(ap))
                ata_busy_sleep(ap, ATA_TMOUT_BOOT_QUICK, ATA_TMOUT_BOOT);

        return 0;
}

/**
 *      ata_std_softreset - reset host port via ATA SRST
 *      @ap: port to reset
 *      @classes: resulting classes of attached devices
 *
 *      Reset host port using ATA SRST.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep)
 *
 *      RETURNS:
 *      0 on success, -errno otherwise.
 */
int ata_std_softreset(struct ata_port *ap, unsigned int *classes)
{
        unsigned int slave_possible = ap->flags & ATA_FLAG_SLAVE_POSS;
        unsigned int devmask = 0, err_mask;
        u8 err;

        DPRINTK("ENTER\n");

        if (ata_port_offline(ap)) {
                classes[0] = ATA_DEV_NONE;
                goto out;
        }

        /* determine if device 0/1 are present */
        if (ata_devchk(ap, 0))
                devmask |= (1 << 0);
        if (slave_possible && ata_devchk(ap, 1))
                devmask |= (1 << 1);

        /* select device 0 again */
        ap->ops->dev_select(ap, 0);

        /* issue bus reset */
        DPRINTK("about to softreset, devmask=%x\n", devmask);
        err_mask = ata_bus_softreset(ap, devmask);
        if (err_mask) {
                ata_port_printk(ap, KERN_ERR, "SRST failed (err_mask=0x%x)\n",
                                err_mask);
                return -EIO;
        }

        /* determine by signature whether we have ATA or ATAPI devices */
        classes[0] = ata_dev_try_classify(ap, 0, &err);
        if (slave_possible && err != 0x81)
                classes[1] = ata_dev_try_classify(ap, 1, &err);

 out:
        DPRINTK("EXIT, classes[0]=%u [1]=%u\n", classes[0], classes[1]);
        return 0;
}

/**
 *      sata_port_hardreset - reset port via SATA phy reset
 *      @ap: port to reset
 *      @timing: timing parameters { interval, duratinon, timeout } in msec
 *
 *      SATA phy-reset host port using DET bits of SControl register.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep)
 *
 *      RETURNS:
 *      0 on success, -errno otherwise.
 */
int sata_port_hardreset(struct ata_port *ap, const unsigned long *timing)
{
        u32 scontrol;
        int rc;

        DPRINTK("ENTER\n");

        if (sata_set_spd_needed(ap)) {
                /* SATA spec says nothing about how to reconfigure
                 * spd.  To be on the safe side, turn off phy during
                 * reconfiguration.  This works for at least ICH7 AHCI
                 * and Sil3124.
                 */
                if ((rc = sata_scr_read(ap, SCR_CONTROL, &scontrol)))
                        goto out;

                scontrol = (scontrol & 0x0f0) | 0x304;

                if ((rc = sata_scr_write(ap, SCR_CONTROL, scontrol)))
                        goto out;

                sata_set_spd(ap);
        }

        /* issue phy wake/reset */
        if ((rc = sata_scr_read(ap, SCR_CONTROL, &scontrol)))
                goto out;

        scontrol = (scontrol & 0x0f0) | 0x301;

        if ((rc = sata_scr_write_flush(ap, SCR_CONTROL, scontrol)))
                goto out;

        /* Couldn't find anything in SATA I/II specs, but AHCI-1.1
         * 10.4.2 says at least 1 ms.
         */
        msleep(1);

        /* bring phy back */
        rc = sata_phy_resume(ap, timing);
 out:
        DPRINTK("EXIT, rc=%d\n", rc);
        return rc;
}

/**
 *      sata_std_hardreset - reset host port via SATA phy reset
 *      @ap: port to reset
 *      @class: resulting class of attached device
 *
 *      SATA phy-reset host port using DET bits of SControl register,
 *      wait for !BSY and classify the attached device.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep)
 *
 *      RETURNS:
 *      0 on success, -errno otherwise.
 */
int sata_std_hardreset(struct ata_port *ap, unsigned int *class)
{
        const unsigned long *timing = sata_ehc_deb_timing(&ap->eh_context);
        int rc;

        DPRINTK("ENTER\n");

        /* do hardreset */
        rc = sata_port_hardreset(ap, timing);
        if (rc) {
                ata_port_printk(ap, KERN_ERR,
                                "COMRESET failed (errno=%d)\n", rc);
                return rc;
        }

        /* TODO: phy layer with polling, timeouts, etc. */
        if (ata_port_offline(ap)) {
                *class = ATA_DEV_NONE;
                DPRINTK("EXIT, link offline\n");
                return 0;
        }

        if (ata_busy_sleep(ap, ATA_TMOUT_BOOT_QUICK, ATA_TMOUT_BOOT)) {
                ata_port_printk(ap, KERN_ERR,
                                "COMRESET failed (device not ready)\n");
                return -EIO;
        }

        ap->ops->dev_select(ap, 0);     /* probably unnecessary */

        *class = ata_dev_try_classify(ap, 0, NULL);

        DPRINTK("EXIT, class=%u\n", *class);
        return 0;
}

/**
 *      ata_std_postreset - standard postreset callback
 *      @ap: the target ata_port
 *      @classes: classes of attached devices
 *
 *      This function is invoked after a successful reset.  Note that
 *      the device might have been reset more than once using
 *      different reset methods before postreset is invoked.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep)
 */
void ata_std_postreset(struct ata_port *ap, unsigned int *classes)
{
        u32 serror;

        DPRINTK("ENTER\n");

        /* print link status */
        sata_print_link_status(ap);

        /* clear SError */
        if (sata_scr_read(ap, SCR_ERROR, &serror) == 0)
                sata_scr_write(ap, SCR_ERROR, serror);

        /* re-enable interrupts */
        if (!ap->ops->error_handler) {
                /* FIXME: hack. create a hook instead */
                if (ap->ioaddr.ctl_addr)
                        ata_irq_on(ap);
        }

        /* is double-select really necessary? */
        if (classes[0] != ATA_DEV_NONE)
                ap->ops->dev_select(ap, 1);
        if (classes[1] != ATA_DEV_NONE)
                ap->ops->dev_select(ap, 0);

        /* bail out if no device is present */
        if (classes[0] == ATA_DEV_NONE && classes[1] == ATA_DEV_NONE) {
                DPRINTK("EXIT, no device\n");
                return;
        }

        /* set up device control */
        if (ap->ioaddr.ctl_addr) {
                if (ap->flags & ATA_FLAG_MMIO)
                        writeb(ap->ctl, (void __iomem *) ap->ioaddr.ctl_addr);
                else
                        outb(ap->ctl, ap->ioaddr.ctl_addr);
        }

        DPRINTK("EXIT\n");
}

/**
 *      ata_dev_same_device - Determine whether new ID matches configured device
 *      @dev: device to compare against
 *      @new_class: class of the new device
 *      @new_id: IDENTIFY page of the new device
 *
 *      Compare @new_class and @new_id against @dev and determine
 *      whether @dev is the device indicated by @new_class and
 *      @new_id.
 *
 *      LOCKING:
 *      None.
 *
 *      RETURNS:
 *      1 if @dev matches @new_class and @new_id, 0 otherwise.
 */
static int ata_dev_same_device(struct ata_device *dev, unsigned int new_class,
                               const u16 *new_id)
{
        const u16 *old_id = dev->id;
        unsigned char model[2][41], serial[2][21];
        u64 new_n_sectors;

        if (dev->class != new_class) {
                ata_dev_printk(dev, KERN_INFO, "class mismatch %d != %d\n",
                               dev->class, new_class);
                return 0;
        }

        ata_id_c_string(old_id, model[0], ATA_ID_PROD_OFS, sizeof(model[0]));
        ata_id_c_string(new_id, model[1], ATA_ID_PROD_OFS, sizeof(model[1]));
        ata_id_c_string(old_id, serial[0], ATA_ID_SERNO_OFS, sizeof(serial[0]));
        ata_id_c_string(new_id, serial[1], ATA_ID_SERNO_OFS, sizeof(serial[1]));
        new_n_sectors = ata_id_n_sectors(new_id);

        if (strcmp(model[0], model[1])) {
                ata_dev_printk(dev, KERN_INFO, "model number mismatch "
                               "'%s' != '%s'\n", model[0], model[1]);
                return 0;
        }

        if (strcmp(serial[0], serial[1])) {
                ata_dev_printk(dev, KERN_INFO, "serial number mismatch "
                               "'%s' != '%s'\n", serial[0], serial[1]);
                return 0;
        }

        if (dev->class == ATA_DEV_ATA && dev->n_sectors != new_n_sectors) {
                ata_dev_printk(dev, KERN_INFO, "n_sectors mismatch "
                               "%llu != %llu\n",
                               (unsigned long long)dev->n_sectors,
                               (unsigned long long)new_n_sectors);
                return 0;
        }

        return 1;
}

/**
 *      ata_dev_revalidate - Revalidate ATA device
 *      @dev: device to revalidate
 *      @readid_flags: read ID flags
 *
 *      Re-read IDENTIFY page and make sure @dev is still attached to
 *      the port.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep)
 *
 *      RETURNS:
 *      0 on success, negative errno otherwise
 */
int ata_dev_revalidate(struct ata_device *dev, unsigned int readid_flags)
{
        unsigned int class = dev->class;
        u16 *id = (void *)dev->ap->sector_buf;
        int rc;

        if (!ata_dev_enabled(dev)) {
                rc = -ENODEV;
                goto fail;
        }

        /* read ID data */
        rc = ata_dev_read_id(dev, &class, readid_flags, id);
        if (rc)
                goto fail;

        /* is the device still there? */
        if (!ata_dev_same_device(dev, class, id)) {
                rc = -ENODEV;
                goto fail;
        }

        memcpy(dev->id, id, sizeof(id[0]) * ATA_ID_WORDS);

        /* configure device according to the new ID */
        rc = ata_dev_configure(dev);
        if (rc == 0)
                return 0;

 fail:
        ata_dev_printk(dev, KERN_ERR, "revalidation failed (errno=%d)\n", rc);
        return rc;
}

struct ata_blacklist_entry {
        const char *model_num;
        const char *model_rev;
        unsigned long horkage;
};

static const struct ata_blacklist_entry ata_device_blacklist [] = {
        /* Devices with DMA related problems under Linux */
        { "WDC AC11000H",       NULL,           ATA_HORKAGE_NODMA },
        { "WDC AC22100H",       NULL,           ATA_HORKAGE_NODMA },
        { "WDC AC32500H",       NULL,           ATA_HORKAGE_NODMA },
        { "WDC AC33100H",       NULL,           ATA_HORKAGE_NODMA },
        { "WDC AC31600H",       NULL,           ATA_HORKAGE_NODMA },
        { "WDC AC32100H",       "24.09P07",     ATA_HORKAGE_NODMA },
        { "WDC AC23200L",       "21.10N21",     ATA_HORKAGE_NODMA },
        { "Compaq CRD-8241B",   NULL,           ATA_HORKAGE_NODMA },
        { "CRD-8400B",          NULL,           ATA_HORKAGE_NODMA },
        { "CRD-8480B",          NULL,           ATA_HORKAGE_NODMA },
        { "CRD-8482B",          NULL,           ATA_HORKAGE_NODMA },
        { "CRD-84",             NULL,           ATA_HORKAGE_NODMA },
        { "SanDisk SDP3B",      NULL,           ATA_HORKAGE_NODMA },
        { "SanDisk SDP3B-64",   NULL,           ATA_HORKAGE_NODMA },
        { "SANYO CD-ROM CRD",   NULL,           ATA_HORKAGE_NODMA },
        { "HITACHI CDR-8",      NULL,           ATA_HORKAGE_NODMA },
        { "HITACHI CDR-8335",   NULL,           ATA_HORKAGE_NODMA },
        { "HITACHI CDR-8435",   NULL,           ATA_HORKAGE_NODMA },
        { "Toshiba CD-ROM XM-6202B", NULL,      ATA_HORKAGE_NODMA },
        { "TOSHIBA CD-ROM XM-1702BC", NULL,     ATA_HORKAGE_NODMA },
        { "CD-532E-A",          NULL,           ATA_HORKAGE_NODMA },
        { "E-IDE CD-ROM CR-840",NULL,           ATA_HORKAGE_NODMA },
        { "CD-ROM Drive/F5A",   NULL,           ATA_HORKAGE_NODMA },
        { "WPI CDD-820",        NULL,           ATA_HORKAGE_NODMA },
        { "SAMSUNG CD-ROM SC-148C", NULL,       ATA_HORKAGE_NODMA },
        { "SAMSUNG CD-ROM SC",  NULL,           ATA_HORKAGE_NODMA },
        { "SanDisk SDP3B-64",   NULL,           ATA_HORKAGE_NODMA },
        { "ATAPI CD-ROM DRIVE 40X MAXIMUM",NULL,ATA_HORKAGE_NODMA },
        { "_NEC DV5800A",       NULL,           ATA_HORKAGE_NODMA },
        { "SAMSUNG CD-ROM SN-124","N001",       ATA_HORKAGE_NODMA },

        /* Devices we expect to fail diagnostics */

        /* Devices where NCQ should be avoided */
        /* NCQ is slow */
        { "WDC WD740ADFD-00",   NULL,           ATA_HORKAGE_NONCQ },

        /* Devices with NCQ limits */

        /* End Marker */
        { }
};

static int ata_strim(char *s, size_t len)
{
        len = strnlen(s, len);

        /* ATAPI specifies that empty space is blank-filled; remove blanks */
        while ((len > 0) && (s[len - 1] == ' ')) {
                len--;
                s[len] = 0;
        }
        return len;
}

unsigned long ata_device_blacklisted(const struct ata_device *dev)
{
        unsigned char model_num[40];
        unsigned char model_rev[16];
        unsigned int nlen, rlen;
        const struct ata_blacklist_entry *ad = ata_device_blacklist;

        ata_id_string(dev->id, model_num, ATA_ID_PROD_OFS,
                          sizeof(model_num));
        ata_id_string(dev->id, model_rev, ATA_ID_FW_REV_OFS,
                          sizeof(model_rev));
        nlen = ata_strim(model_num, sizeof(model_num));
        rlen = ata_strim(model_rev, sizeof(model_rev));

        while (ad->model_num) {
                if (!strncmp(ad->model_num, model_num, nlen)) {
                        if (ad->model_rev == NULL)
                                return ad->horkage;
                        if (!strncmp(ad->model_rev, model_rev, rlen))