libata: add qc_fill_rtf port operation

[safe/jmp/linux-2.6] / 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/
 *
 *  Standards documents from:
 *      http://www.t13.org (ATA standards, PCI DMA IDE spec)
 *      http://www.t10.org (SCSI MMC - for ATAPI MMC)
 *      http://www.sata-io.org (SATA)
 *      http://www.compactflash.org (CF)
 *      http://www.qic.org (QIC157 - Tape and DSC)
 *      http://www.ce-ata.org (CE-ATA: not supported)
 *
 */

#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/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 <linux/io.h>
#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_host.h>
#include <linux/libata.h>
#include <asm/semaphore.h>
#include <asm/byteorder.h>
#include <linux/cdrom.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 };

const struct ata_port_operations ata_base_port_ops = {
        .qc_fill_rtf            = ata_sff_qc_fill_rtf,
        .prereset               = ata_std_prereset,
        .postreset              = ata_std_postreset,
        .error_handler          = ata_std_error_handler,
};

const struct ata_port_operations sata_port_ops = {
        .inherits               = &ata_base_port_ops,

        .qc_defer               = ata_std_qc_defer,
        .hardreset              = sata_std_hardreset,
        .sff_dev_select         = ata_noop_dev_select,
};

const struct ata_port_operations sata_pmp_port_ops = {
        .inherits               = &sata_port_ops,

        .pmp_prereset           = ata_std_prereset,
        .pmp_hardreset          = sata_std_hardreset,
        .pmp_postreset          = ata_std_postreset,
        .error_handler          = sata_pmp_error_handler,
};

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 unsigned int ata_dev_set_feature(struct ata_device *dev,
                                        u8 enable, u8 feature);
static void ata_dev_xfermask(struct ata_device *dev);
static unsigned long ata_dev_blacklisted(const struct ata_device *dev);

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

struct workqueue_struct *ata_aux_wq;

struct ata_force_param {
        const char      *name;
        unsigned int    cbl;
        int             spd_limit;
        unsigned long   xfer_mask;
        unsigned int    horkage_on;
        unsigned int    horkage_off;
};

struct ata_force_ent {
        int                     port;
        int                     device;
        struct ata_force_param  param;
};

static struct ata_force_ent *ata_force_tbl;
static int ata_force_tbl_size;

static char ata_force_param_buf[PAGE_SIZE] __initdata;
/* param_buf is thrown away after initialization, disallow read */
module_param_string(force, ata_force_param_buf, sizeof(ata_force_param_buf), 0);
MODULE_PARM_DESC(force, "Force ATA configurations including cable type, link speed and transfer mode (see Documentation/kernel-parameters.txt for details)");

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

static 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 atapi_passthru16 = 1;
module_param(atapi_passthru16, int, 0444);
MODULE_PARM_DESC(atapi_passthru16, "Enable ATA_16 passthru for ATAPI devices; on by default (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_ignore_hpa;
module_param_named(ignore_hpa, ata_ignore_hpa, int, 0644);
MODULE_PARM_DESC(ignore_hpa, "Ignore HPA limit (0=keep BIOS limits, 1=ignore limits, using full disk)");

static int libata_dma_mask = ATA_DMA_MASK_ATA|ATA_DMA_MASK_ATAPI|ATA_DMA_MASK_CFA;
module_param_named(dma, libata_dma_mask, int, 0444);
MODULE_PARM_DESC(dma, "DMA enable/disable (0x1==ATA, 0x2==ATAPI, 0x4==CF)");

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)");

int libata_noacpi = 0;
module_param_named(noacpi, libata_noacpi, int, 0444);
MODULE_PARM_DESC(noacpi, "Disables the use of ACPI in probe/suspend/resume when set");

int libata_allow_tpm = 0;
module_param_named(allow_tpm, libata_allow_tpm, int, 0444);
MODULE_PARM_DESC(allow_tpm, "Permit the use of TPM commands");

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


/**
 *      ata_force_cbl - force cable type according to libata.force
 *      @ap: ATA port of interest
 *
 *      Force cable type according to libata.force and whine about it.
 *      The last entry which has matching port number is used, so it
 *      can be specified as part of device force parameters.  For
 *      example, both "a:40c,1.00:udma4" and "1.00:40c,udma4" have the
 *      same effect.
 *
 *      LOCKING:
 *      EH context.
 */
void ata_force_cbl(struct ata_port *ap)
{
        int i;

        for (i = ata_force_tbl_size - 1; i >= 0; i--) {
                const struct ata_force_ent *fe = &ata_force_tbl[i];

                if (fe->port != -1 && fe->port != ap->print_id)
                        continue;

                if (fe->param.cbl == ATA_CBL_NONE)
                        continue;

                ap->cbl = fe->param.cbl;
                ata_port_printk(ap, KERN_NOTICE,
                                "FORCE: cable set to %s\n", fe->param.name);
                return;
        }
}

/**
 *      ata_force_spd_limit - force SATA spd limit according to libata.force
 *      @link: ATA link of interest
 *
 *      Force SATA spd limit according to libata.force and whine about
 *      it.  When only the port part is specified (e.g. 1:), the limit
 *      applies to all links connected to both the host link and all
 *      fan-out ports connected via PMP.  If the device part is
 *      specified as 0 (e.g. 1.00:), it specifies the first fan-out
 *      link not the host link.  Device number 15 always points to the
 *      host link whether PMP is attached or not.
 *
 *      LOCKING:
 *      EH context.
 */
static void ata_force_spd_limit(struct ata_link *link)
{
        int linkno, i;

        if (ata_is_host_link(link))
                linkno = 15;
        else
                linkno = link->pmp;

        for (i = ata_force_tbl_size - 1; i >= 0; i--) {
                const struct ata_force_ent *fe = &ata_force_tbl[i];

                if (fe->port != -1 && fe->port != link->ap->print_id)
                        continue;

                if (fe->device != -1 && fe->device != linkno)
                        continue;

                if (!fe->param.spd_limit)
                        continue;

                link->hw_sata_spd_limit = (1 << fe->param.spd_limit) - 1;
                ata_link_printk(link, KERN_NOTICE,
                        "FORCE: PHY spd limit set to %s\n", fe->param.name);
                return;
        }
}

/**
 *      ata_force_xfermask - force xfermask according to libata.force
 *      @dev: ATA device of interest
 *
 *      Force xfer_mask according to libata.force and whine about it.
 *      For consistency with link selection, device number 15 selects
 *      the first device connected to the host link.
 *
 *      LOCKING:
 *      EH context.
 */
static void ata_force_xfermask(struct ata_device *dev)
{
        int devno = dev->link->pmp + dev->devno;
        int alt_devno = devno;
        int i;

        /* allow n.15 for the first device attached to host port */
        if (ata_is_host_link(dev->link) && devno == 0)
                alt_devno = 15;

        for (i = ata_force_tbl_size - 1; i >= 0; i--) {
                const struct ata_force_ent *fe = &ata_force_tbl[i];
                unsigned long pio_mask, mwdma_mask, udma_mask;

                if (fe->port != -1 && fe->port != dev->link->ap->print_id)
                        continue;

                if (fe->device != -1 && fe->device != devno &&
                    fe->device != alt_devno)
                        continue;

                if (!fe->param.xfer_mask)
                        continue;

                ata_unpack_xfermask(fe->param.xfer_mask,
                                    &pio_mask, &mwdma_mask, &udma_mask);
                if (udma_mask)
                        dev->udma_mask = udma_mask;
                else if (mwdma_mask) {
                        dev->udma_mask = 0;
                        dev->mwdma_mask = mwdma_mask;
                } else {
                        dev->udma_mask = 0;
                        dev->mwdma_mask = 0;
                        dev->pio_mask = pio_mask;
                }

                ata_dev_printk(dev, KERN_NOTICE,
                        "FORCE: xfer_mask set to %s\n", fe->param.name);
                return;
        }
}

/**
 *      ata_force_horkage - force horkage according to libata.force
 *      @dev: ATA device of interest
 *
 *      Force horkage according to libata.force and whine about it.
 *      For consistency with link selection, device number 15 selects
 *      the first device connected to the host link.
 *
 *      LOCKING:
 *      EH context.
 */
static void ata_force_horkage(struct ata_device *dev)
{
        int devno = dev->link->pmp + dev->devno;
        int alt_devno = devno;
        int i;

        /* allow n.15 for the first device attached to host port */
        if (ata_is_host_link(dev->link) && devno == 0)
                alt_devno = 15;

        for (i = 0; i < ata_force_tbl_size; i++) {
                const struct ata_force_ent *fe = &ata_force_tbl[i];

                if (fe->port != -1 && fe->port != dev->link->ap->print_id)
                        continue;

                if (fe->device != -1 && fe->device != devno &&
                    fe->device != alt_devno)
                        continue;

                if (!(~dev->horkage & fe->param.horkage_on) &&
                    !(dev->horkage & fe->param.horkage_off))
                        continue;

                dev->horkage |= fe->param.horkage_on;
                dev->horkage &= ~fe->param.horkage_off;

                ata_dev_printk(dev, KERN_NOTICE,
                        "FORCE: horkage modified (%s)\n", fe->param.name);
        }
}

/**
 *      atapi_cmd_type - Determine ATAPI command type from SCSI opcode
 *      @opcode: SCSI opcode
 *
 *      Determine ATAPI command type from @opcode.
 *
 *      LOCKING:
 *      None.
 *
 *      RETURNS:
 *      ATAPI_{READ|WRITE|READ_CD|PASS_THRU|MISC}
 */
int atapi_cmd_type(u8 opcode)
{
        switch (opcode) {
        case GPCMD_READ_10:
        case GPCMD_READ_12:
                return ATAPI_READ;

        case GPCMD_WRITE_10:
        case GPCMD_WRITE_12:
        case GPCMD_WRITE_AND_VERIFY_10:
                return ATAPI_WRITE;

        case GPCMD_READ_CD:
        case GPCMD_READ_CD_MSF:
                return ATAPI_READ_CD;

        case ATA_16:
        case ATA_12:
                if (atapi_passthru16)
                        return ATAPI_PASS_THRU;
                /* fall thru */
        default:
                return ATAPI_MISC;
        }
}

/**
 *      ata_tf_to_fis - Convert ATA taskfile to SATA FIS structure
 *      @tf: Taskfile to convert
 *      @pmp: Port multiplier port
 *      @is_cmd: This FIS is for command
 *      @fis: Buffer into which data will output
 *
 *      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 pmp, int is_cmd, u8 *fis)
{
        fis[0] = 0x27;                  /* Register - Host to Device FIS */
        fis[1] = pmp & 0xf;             /* Port multiplier number*/
        if (is_cmd)
                fis[1] |= (1 << 7);     /* 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->link->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 (ata_ncq_enabled(dev) && 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.
 */
unsigned long ata_pack_xfermask(unsigned long pio_mask,
                                unsigned long mwdma_mask,
                                unsigned long 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.
 */
void ata_unpack_xfermask(unsigned long xfer_mask, unsigned long *pio_mask,
                         unsigned long *mwdma_mask, unsigned long *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_NR_PIO_MODES, XFER_PIO_0 },
        { ATA_SHIFT_MWDMA, ATA_NR_MWDMA_MODES, XFER_MW_DMA_0 },
        { ATA_SHIFT_UDMA, ATA_NR_UDMA_MODES, 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, 0xff if no match found.
 */
u8 ata_xfer_mask2mode(unsigned long 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 0xff;
}

/**
 *      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.
 */
unsigned long 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 ((2 << (ent->shift + xfer_mode - ent->base)) - 1)
                                & ~((1 << ent->shift) - 1);
        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.
 */
int ata_xfer_mode2shift(unsigned long 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>".
 */
const char *ata_mode_string(unsigned long 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)) {
                if (ata_msg_drv(dev->link->ap))
                        ata_dev_printk(dev, KERN_WARNING, "disabled\n");
                ata_acpi_on_disable(dev);
                ata_down_xfermask_limit(dev, ATA_DNXFER_FORCE_PIO0 |
                                             ATA_DNXFER_QUIET);
                dev->class++;
        }
}

static int ata_dev_set_dipm(struct ata_device *dev, enum link_pm policy)
{
        struct ata_link *link = dev->link;
        struct ata_port *ap = link->ap;
        u32 scontrol;
        unsigned int err_mask;
        int rc;

        /*
         * disallow DIPM for drivers which haven't set
         * ATA_FLAG_IPM.  This is because when DIPM is enabled,
         * phy ready will be set in the interrupt status on
         * state changes, which will cause some drivers to
         * think there are errors - additionally drivers will
         * need to disable hot plug.
         */
        if (!(ap->flags & ATA_FLAG_IPM) || !ata_dev_enabled(dev)) {
                ap->pm_policy = NOT_AVAILABLE;
                return -EINVAL;
        }

        /*
         * For DIPM, we will only enable it for the
         * min_power setting.
         *
         * Why?  Because Disks are too stupid to know that
         * If the host rejects a request to go to SLUMBER
         * they should retry at PARTIAL, and instead it
         * just would give up.  So, for medium_power to
         * work at all, we need to only allow HIPM.
         */
        rc = sata_scr_read(link, SCR_CONTROL, &scontrol);
        if (rc)
                return rc;

        switch (policy) {
        case MIN_POWER:
                /* no restrictions on IPM transitions */
                scontrol &= ~(0x3 << 8);
                rc = sata_scr_write(link, SCR_CONTROL, scontrol);
                if (rc)
                        return rc;

                /* enable DIPM */
                if (dev->flags & ATA_DFLAG_DIPM)
                        err_mask = ata_dev_set_feature(dev,
                                        SETFEATURES_SATA_ENABLE, SATA_DIPM);
                break;
        case MEDIUM_POWER:
                /* allow IPM to PARTIAL */
                scontrol &= ~(0x1 << 8);
                scontrol |= (0x2 << 8);
                rc = sata_scr_write(link, SCR_CONTROL, scontrol);
                if (rc)
                        return rc;

                /*
                 * we don't have to disable DIPM since IPM flags
                 * disallow transitions to SLUMBER, which effectively
                 * disable DIPM if it does not support PARTIAL
                 */
                break;
        case NOT_AVAILABLE:
        case MAX_PERFORMANCE:
                /* disable all IPM transitions */
                scontrol |= (0x3 << 8);
                rc = sata_scr_write(link, SCR_CONTROL, scontrol);
                if (rc)
                        return rc;

                /*
                 * we don't have to disable DIPM since IPM flags
                 * disallow all transitions which effectively
                 * disable DIPM anyway.
                 */
                break;
        }

        /* FIXME: handle SET FEATURES failure */
        (void) err_mask;

        return 0;
}

/**
 *      ata_dev_enable_pm - enable SATA interface power management
 *      @dev:  device to enable power management
 *      @policy: the link power management policy
 *
 *      Enable SATA Interface power management.  This will enable
 *      Device Interface Power Management (DIPM) for min_power
 *      policy, and then call driver specific callbacks for
 *      enabling Host Initiated Power management.
 *
 *      Locking: Caller.
 *      Returns: -EINVAL if IPM is not supported, 0 otherwise.
 */
void ata_dev_enable_pm(struct ata_device *dev, enum link_pm policy)
{
        int rc = 0;
        struct ata_port *ap = dev->link->ap;

        /* set HIPM first, then DIPM */
        if (ap->ops->enable_pm)
                rc = ap->ops->enable_pm(ap, policy);
        if (rc)
                goto enable_pm_out;
        rc = ata_dev_set_dipm(dev, policy);

enable_pm_out:
        if (rc)
                ap->pm_policy = MAX_PERFORMANCE;
        else
                ap->pm_policy = policy;
        return /* rc */;        /* hopefully we can use 'rc' eventually */
}

#ifdef CONFIG_PM
/**
 *      ata_dev_disable_pm - disable SATA interface power management
 *      @dev: device to disable power management
 *
 *      Disable SATA Interface power management.  This will disable
 *      Device Interface Power Management (DIPM) without changing
 *      policy,  call driver specific callbacks for disabling Host
 *      Initiated Power management.
 *
 *      Locking: Caller.
 *      Returns: void
 */
static void ata_dev_disable_pm(struct ata_device *dev)
{
        struct ata_port *ap = dev->link->ap;

        ata_dev_set_dipm(dev, MAX_PERFORMANCE);
        if (ap->ops->disable_pm)
                ap->ops->disable_pm(ap);
}
#endif  /* CONFIG_PM */

void ata_lpm_schedule(struct ata_port *ap, enum link_pm policy)
{
        ap->pm_policy = policy;
        ap->link.eh_info.action |= ATA_EH_LPM;
        ap->link.eh_info.flags |= ATA_EHI_NO_AUTOPSY;
        ata_port_schedule_eh(ap);
}

#ifdef CONFIG_PM
static void ata_lpm_enable(struct ata_host *host)
{
        struct ata_link *link;
        struct ata_port *ap;
        struct ata_device *dev;
        int i;

        for (i = 0; i < host->n_ports; i++) {
                ap = host->ports[i];
                ata_port_for_each_link(link, ap) {
                        ata_link_for_each_dev(dev, link)
                                ata_dev_disable_pm(dev);
                }
        }
}

static void ata_lpm_disable(struct ata_host *host)
{
        int i;

        for (i = 0; i < host->n_ports; i++) {
                struct ata_port *ap = host->ports[i];
                ata_lpm_schedule(ap, ap->pm_policy);
        }
}
#endif  /* CONFIG_PM */

/**
 *      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, %ATA_DEV_PMP 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.
         *
         * ATA/ATAPI-7 (d1532v1r1: Feb. 19, 2003) specified separate
         * signatures for ATA and ATAPI devices attached on SerialATA,
         * 0x3c/0xc3 and 0x69/0x96 respectively.  However, SerialATA
         * spec has never mentioned about using different signatures
         * for ATA/ATAPI devices.  Then, Serial ATA II: Port
         * Multiplier specification began to use 0x69/0x96 to identify
         * port multpliers and 0x3c/0xc3 to identify SEMB device.
         * ATA/ATAPI-7 dropped descriptions about 0x3c/0xc3 and
         * 0x69/0x96 shortly and described them as reserved for
         * SerialATA.
         *
         * We follow the current spec and consider that 0x69/0x96
         * identifies a port multiplier and 0x3c/0xc3 a SEMB device.
         */
        if ((tf->lbam == 0) && (tf->lbah == 0)) {
                DPRINTK("found ATA device by sig\n");
                return ATA_DEV_ATA;
        }

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

        if ((tf->lbam == 0x69) && (tf->lbah == 0x96)) {
                DPRINTK("found PMP device by sig\n");
                return ATA_DEV_PMP;
        }

        if ((tf->lbam == 0x3c) && (tf->lbah == 0xc3)) {
                printk(KERN_INFO "ata: SEMB device ignored\n");
                return ATA_DEV_SEMB_UNSUP; /* not yet */
        }

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

/**
 *      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];
        }
}

u64 ata_tf_to_lba48(const struct ata_taskfile *tf)
{
        u64 sectors = 0;

        sectors |= ((u64)(tf->hob_lbah & 0xff)) << 40;
        sectors |= ((u64)(tf->hob_lbam & 0xff)) << 32;
        sectors |= (tf->hob_lbal & 0xff) << 24;
        sectors |= (tf->lbah & 0xff) << 16;
        sectors |= (tf->lbam & 0xff) << 8;
        sectors |= (tf->lbal & 0xff);

        return sectors;
}

u64 ata_tf_to_lba(const struct ata_taskfile *tf)
{
        u64 sectors = 0;

        sectors |= (tf->device & 0x0f) << 24;
        sectors |= (tf->lbah & 0xff) << 16;
        sectors |= (tf->lbam & 0xff) << 8;
        sectors |= (tf->lbal & 0xff);

        return sectors;
}

/**
 *      ata_read_native_max_address - Read native max address
 *      @dev: target device
 *      @max_sectors: out parameter for the result native max address
 *
 *      Perform an LBA48 or LBA28 native size query upon the device in
 *      question.
 *
 *      RETURNS:
 *      0 on success, -EACCES if command is aborted by the drive.
 *      -EIO on other errors.
 */
static int ata_read_native_max_address(struct ata_device *dev, u64 *max_sectors)
{
        unsigned int err_mask;
        struct ata_taskfile tf;
        int lba48 = ata_id_has_lba48(dev->id);

        ata_tf_init(dev, &tf);

        /* always clear all address registers */
        tf.flags |= ATA_TFLAG_DEVICE | ATA_TFLAG_ISADDR;

        if (lba48) {
                tf.command = ATA_CMD_READ_NATIVE_MAX_EXT;
                tf.flags |= ATA_TFLAG_LBA48;
        } else
                tf.command = ATA_CMD_READ_NATIVE_MAX;

        tf.protocol |= ATA_PROT_NODATA;
        tf.device |= ATA_LBA;

        err_mask = ata_exec_internal(dev, &tf, NULL, DMA_NONE, NULL, 0, 0);
        if (err_mask) {
                ata_dev_printk(dev, KERN_WARNING, "failed to read native "
                               "max address (err_mask=0x%x)\n", err_mask);
                if (err_mask == AC_ERR_DEV && (tf.feature & ATA_ABORTED))
                        return -EACCES;
                return -EIO;
        }

        if (lba48)
                *max_sectors = ata_tf_to_lba48(&tf) + 1;
        else
                *max_sectors = ata_tf_to_lba(&tf) + 1;
        if (dev->horkage & ATA_HORKAGE_HPA_SIZE)
                (*max_sectors)--;
        return 0;
}

/**
 *      ata_set_max_sectors - Set max sectors
 *      @dev: target device
 *      @new_sectors: new max sectors value to set for the device
 *
 *      Set max sectors of @dev to @new_sectors.
 *
 *      RETURNS:
 *      0 on success, -EACCES if command is aborted or denied (due to
 *      previous non-volatile SET_MAX) by the drive.  -EIO on other
 *      errors.
 */
static int ata_set_max_sectors(struct ata_device *dev, u64 new_sectors)
{
        unsigned int err_mask;
        struct ata_taskfile tf;
        int lba48 = ata_id_has_lba48(dev->id);

        new_sectors--;

        ata_tf_init(dev, &tf);

        tf.flags |= ATA_TFLAG_DEVICE | ATA_TFLAG_ISADDR;

        if (lba48) {
                tf.command = ATA_CMD_SET_MAX_EXT;
                tf.flags |= ATA_TFLAG_LBA48;

                tf.hob_lbal = (new_sectors >> 24) & 0xff;
                tf.hob_lbam = (new_sectors >> 32) & 0xff;
                tf.hob_lbah = (new_sectors >> 40) & 0xff;
        } else {
                tf.command = ATA_CMD_SET_MAX;

                tf.device |= (new_sectors >> 24) & 0xf;
        }

        tf.protocol |= ATA_PROT_NODATA;
        tf.device |= ATA_LBA;

        tf.lbal = (new_sectors >> 0) & 0xff;
        tf.lbam = (new_sectors >> 8) & 0xff;
        tf.lbah = (new_sectors >> 16) & 0xff;

        err_mask = ata_exec_internal(dev, &tf, NULL, DMA_NONE, NULL, 0, 0);
        if (err_mask) {
                ata_dev_printk(dev, KERN_WARNING, "failed to set "
                               "max address (err_mask=0x%x)\n", err_mask);
                if (err_mask == AC_ERR_DEV &&
                    (tf.feature & (ATA_ABORTED | ATA_IDNF)))
                        return -EACCES;
                return -EIO;
        }

        return 0;
}

/**
 *      ata_hpa_resize          -       Resize a device with an HPA set
 *      @dev: Device to resize
 *
 *      Read the size of an LBA28 or LBA48 disk with HPA features and resize
 *      it if required to the full size of the media. The caller must check
 *      the drive has the HPA feature set enabled.
 *
 *      RETURNS:
 *      0 on success, -errno on failure.
 */
static int ata_hpa_resize(struct ata_device *dev)
{
        struct ata_eh_context *ehc = &dev->link->eh_context;
        int print_info = ehc->i.flags & ATA_EHI_PRINTINFO;
        u64 sectors = ata_id_n_sectors(dev->id);
        u64 native_sectors;
        int rc;

        /* do we need to do it? */
        if (dev->class != ATA_DEV_ATA ||
            !ata_id_has_lba(dev->id) || !ata_id_hpa_enabled(dev->id) ||
            (dev->horkage & ATA_HORKAGE_BROKEN_HPA))
                return 0;

        /* read native max address */
        rc = ata_read_native_max_address(dev, &native_sectors);
        if (rc) {
                /* If device aborted the command or HPA isn't going to
                 * be unlocked, skip HPA resizing.
                 */
                if (rc == -EACCES || !ata_ignore_hpa) {
                        ata_dev_printk(dev, KERN_WARNING, "HPA support seems "
                                       "broken, skipping HPA handling\n");
                        dev->horkage |= ATA_HORKAGE_BROKEN_HPA;

                        /* we can continue if device aborted the command */
                        if (rc == -EACCES)
                                rc = 0;
                }

                return rc;
        }

        /* nothing to do? */
        if (native_sectors <= sectors || !ata_ignore_hpa) {
                if (!print_info || native_sectors == sectors)
                        return 0;

                if (native_sectors > sectors)
                        ata_dev_printk(dev, KERN_INFO,
                                "HPA detected: current %llu, native %llu\n",
                                (unsigned long long)sectors,
                                (unsigned long long)native_sectors);
                else if (native_sectors < sectors)
                        ata_dev_printk(dev, KERN_WARNING,
                                "native sectors (%llu) is smaller than "
                                "sectors (%llu)\n",
                                (unsigned long long)native_sectors,
                                (unsigned long long)sectors);
                return 0;
        }

        /* let's unlock HPA */
        rc = ata_set_max_sectors(dev, native_sectors);
        if (rc == -EACCES) {
                /* if device aborted the command, skip HPA resizing */
                ata_dev_printk(dev, KERN_WARNING, "device aborted resize "
                               "(%llu -> %llu), skipping HPA handling\n",
                               (unsigned long long)sectors,
                               (unsigned long long)native_sectors);
                dev->horkage |= ATA_HORKAGE_BROKEN_HPA;
                return 0;
        } else if (rc)
                return rc;

        /* re-read IDENTIFY data */
        rc = ata_dev_reread_id(dev, 0);
        if (rc) {
                ata_dev_printk(dev, KERN_ERR, "failed to re-read IDENTIFY "
                               "data after HPA resizing\n");
                return rc;
        }

        if (print_info) {
                u64 new_sectors = ata_id_n_sectors(dev->id);
                ata_dev_printk(dev, KERN_INFO,
                        "HPA unlocked: %llu -> %llu, native %llu\n",
                        (unsigned long long)sectors,
                        (unsigned long long)new_sectors,
                        (unsigned long long)native_sectors);
        }

        return 0;
}

/**
 *      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_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
 */
unsigned long ata_id_xfermask(const u16 *id)
{
        unsigned long 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_pio_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_pio_queue_task() may be ignored for EH
 *      synchronization.
 *
 *      LOCKING:
 *      Inherited from caller.
 */
void ata_pio_queue_task(struct ata_port *ap, void *data, unsigned long delay)
{
        ap->port_task_data = data;

        /* may fail if ata_port_flush_task() in progress */
        queue_delayed_work(ata_wq, &ap->port_task, delay);
}

/**
 *      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)
{
        DPRINTK("ENTER\n");

        cancel_rearming_delayed_work(&ap->port_task);

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

static 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
 *      @sgl: sg list for the data buffer of the command
 *      @n_elem: Number of sg entries
 *      @timeout: Timeout in msecs (0 for default)
 *
 *      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 *sgl,
                              unsigned int n_elem, unsigned long timeout)
{
        struct ata_link *link = dev->link;
        struct ata_port *ap = link->ap;
        u8 command = tf->command;
        struct ata_queued_cmd *qc;
        unsigned int tag, preempted_tag;
        u32 preempted_sactive, preempted_qc_active;
        int preempted_nr_active_links;
        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 = link->active_tag;
        preempted_sactive = link->sactive;
        preempted_qc_active = ap->qc_active;
        preempted_nr_active_links = ap->nr_active_links;
        link->active_tag = ATA_TAG_POISON;
        link->sactive = 0;
        ap->qc_active = 0;
        ap->nr_active_links = 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;
                struct scatterlist *sg;

                for_each_sg(sgl, sg, n_elem, i)
                        buflen += sg->length;

                ata_sg_init(qc, sgl, n_elem);
                qc->nbytes = buflen;
        }

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

        ata_qc_issue(qc);

        spin_unlock_irqrestore(ap->lock, flags);

        if (!timeout)
                timeout = ata_probe_timeout * 1000 / HZ;

        rc = wait_for_completion_timeout(&wait, msecs_to_jiffies(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);

        /* perform minimal error analysis */
        if (qc->flags & ATA_QCFLAG_FAILED) {
                if (qc->result_tf.command & (ATA_ERR | ATA_DF))
                        qc->err_mask |= AC_ERR_DEV;

                if (!qc->err_mask)
                        qc->err_mask |= AC_ERR_OTHER;

                if (qc->err_mask & ~AC_ERR_OTHER)
                        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);
        link->active_tag = preempted_tag;
        link->sactive = preempted_sactive;
        ap->qc_active = preempted_qc_active;
        ap->nr_active_links = preempted_nr_active_links;

        /* 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
 *      @timeout: Timeout in msecs (0 for default)
 *
 *      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,
                           unsigned long timeout)
{
        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,
                                    timeout);
}

/**
 *      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, 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)
{
        /* Controller doesn't support  IORDY. Probably a pointless check
           as the caller should know this */
        if (adev->link->ap->flags & ATA_FLAG_NO_IORDY)
                return 0;
        /* PIO3 and higher it is mandatory */
        if (adev->pio_mode > XFER_PIO_2)
                return 1;
        /* We turn it on when possible */
        if (ata_id_has_iordy(adev->id))
                return 1;
        return 0;
}

/**
 *      ata_pio_mask_no_iordy   -       Return the non IORDY mask
 *      @adev: ATA device
 *
 *      Compute the highest mode possible if we are not using iordy. Return
 *      -1 if no iordy mode is available.
 */

static u32 ata_pio_mask_no_iordy(const struct ata_device *adev)
{
        /* If we have no drive specific rule, then PIO 2 is non IORDY */
        if (adev->id[ATA_ID_FIELD_VALID] & 2) { /* EIDE */
                u16 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 3 << ATA_SHIFT_PIO;
                        return 7 << ATA_SHIFT_PIO;
                }
        }
        return 3 << ATA_SHIFT_PIO;
}

/**
 *      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.
 *
 *      FIXME: ATA_CMD_ID_ATA is optional for early drives and right
 *      now we abort if we hit that case.
 *
 *      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->link->ap;
        unsigned int class = *p_class;
        struct ata_taskfile tf;
        unsigned int err_mask = 0;
        const char *reason;
        int may_fallback = 1, tried_spinup = 0;
        int rc;

        if (ata_msg_ctl(ap))
                ata_dev_printk(dev, KERN_DEBUG, "%s: ENTER\n", __func__);

 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;

        /* Some devices choke if TF registers contain garbage.  Make
         * sure those are properly initialized.
         */
        tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;

        /* Device presence detection is unreliable on some
         * controllers.  Always poll IDENTIFY if available.
         */
        tf.flags |= ATA_TFLAG_POLLING;

        err_mask = ata_exec_internal(dev, &tf, NULL, DMA_FROM_DEVICE,
                                     id, sizeof(id[0]) * ATA_ID_WORDS, 0);
        if (err_mask) {
                if (err_mask & AC_ERR_NODEV_HINT) {
                        ata_dev_printk(dev, KERN_DEBUG,
                                       "NODEV after polling detection\n");
                        return -ENOENT;
                }

                if ((err_mask == AC_ERR_DEV) && (tf.feature & ATA_ABORTED)) {
                        /* Device or controller might have reported
                         * the wrong device class.  Give a shot at the
                         * other IDENTIFY if the current one is
                         * aborted by the device.
                         */
                        if (may_fallback) {
                                may_fallback = 0;

                                if (class == ATA_DEV_ATA)
                                        class = ATA_DEV_ATAPI;
                                else
                                        class = ATA_DEV_ATA;
                                goto retry;
                        }

                        /* Control reaches here iff the device aborted
                         * both flavors of IDENTIFYs which happens
                         * sometimes with phantom devices.
                         */
                        ata_dev_printk(dev, KERN_DEBUG,
                                       "both IDENTIFYs aborted, assuming NODEV\n");
                        return -ENOENT;
                }

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

        /* Falling back doesn't make sense if ID data was read
         * successfully at least once.
         */
        may_fallback = 0;

        swap_buf_le16(id, ATA_ID_WORDS);

        /* sanity check */
        rc = -EINVAL;
        reason = "device reports invalid 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 (!tried_spinup && (id[2] == 0x37c8 || id[2] == 0x738c)) {
                tried_spinup = 1;
                /*
                 * Drive powered-up in standby mode, and requires a specific
                 * SET_FEATURES spin-up subcommand before it will accept
                 * anything other than the original IDENTIFY command.
                 */
                err_mask = ata_dev_set_feature(dev, SETFEATURES_SPINUP, 0);
                if (err_mask && id[2] != 0x738c) {
                        rc = -EIO;
                        reason = "SPINUP failed";
                        goto err_out;
                }
                /*
                 * If the drive initially returned incomplete IDENTIFY info,
                 * we now must reissue the IDENTIFY command.
                 */
                if (id[2] == 0x37c8)
                        goto retry;
        }

        if ((flags & ATA_READID_POSTRESET) && class == ATA_DEV_ATA) {
                /*
                 * The exact sequence expected by certain pre-ATA4 drives is:
                 * SRST RESET
                 * IDENTIFY (optional in early ATA)
                 * INITIALIZE DEVICE PARAMETERS (later IDE and ATA)
                 * anything else..
                 * Some drives were very specific about that exact sequence.
                 *
                 * Note that ATA4 says lba is mandatory so the second check
                 * shoud never trigger.
                 */
                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)
{
        struct ata_port *ap = dev->link->ap;
        return ((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->link->ap;
        int hdepth = 0, ddepth = ata_id_queue_depth(dev->id);

        if (!ata_id_has_ncq(dev->id)) {
                desc[0] = '\0';
                return;
        }
        if (dev->horkage & 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);
}

/**
 *      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->link->ap;
        struct ata_eh_context *ehc = &dev->link->eh_context;
        int print_info = ehc->i.flags & ATA_EHI_PRINTINFO;
        const u16 *id = dev->id;
        unsigned long xfer_mask;
        char revbuf[7];         /* XYZ-99\0 */
        char fwrevbuf[ATA_ID_FW_REV_LEN+1];
        char modelbuf[ATA_ID_PROD_LEN+1];
        int rc;

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

        if (ata_msg_probe(ap))
                ata_dev_printk(dev, KERN_DEBUG, "%s: ENTER\n", __func__);

        /* set horkage */
        dev->horkage |= ata_dev_blacklisted(dev);
        ata_force_horkage(dev);

        /* let ACPI work its magic */
        rc = ata_acpi_on_devcfg(dev);
        if (rc)
                return rc;

        /* massage HPA, do it early as it might change IDENTIFY data */
        rc = ata_hpa_resize(dev);
        if (rc)
                return rc;

        /* 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",
                               __func__,
                               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);

        /* SCSI only uses 4-char revisions, dump full 8 chars from ATA */
        ata_id_c_string(dev->id, fwrevbuf, ATA_ID_FW_REV,
                        sizeof(fwrevbuf));

        ata_id_c_string(dev->id, modelbuf, ATA_ID_PROD,
                        sizeof(modelbuf));

        /* 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,
                                               "supports DRM functions and may "
                                               "not be fully accessable.\n");
                        snprintf(revbuf, 7, "CFA");
                } else {
                        snprintf(revbuf, 7, "ATA-%d", ata_id_major_version(id));
                        /* Warn the user if the device has TPM extensions */
                        if (ata_id_has_tpm(id))
                                ata_dev_printk(dev, KERN_WARNING,
                                               "supports DRM functions and may "
                                               "not be fully accessable.\n");
                }

                dev->n_sectors = ata_id_n_sectors(id);

                if (dev->id[59] & 0x100)
                        dev->multi_count = dev->id[59] & 0xff;

                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: %s, %s, max %s\n",
                                        revbuf, modelbuf, fwrevbuf,
                                        ata_mode_string(xfer_mask));
                                ata_dev_printk(dev, KERN_INFO,
                                        "%Lu sectors, multi %u: %s %s\n",
                                        (unsigned long long)dev->n_sectors,
                                        dev->multi_count, 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: %s, %s, max %s\n",
                                        revbuf, modelbuf, fwrevbuf,
                                        ata_mode_string(xfer_mask));
                                ata_dev_printk(dev, KERN_INFO,
                                        "%Lu sectors, multi %u, CHS %u/%u/%u\n",
                                        (unsigned long long)dev->n_sectors,
                                        dev->multi_count, dev->cylinders,
                                        dev->heads, dev->sectors);
                        }
                }

                dev->cdb_len = 16;
        }

        /* ATAPI-specific feature tests */
        else if (dev->class == ATA_DEV_ATAPI) {
                const char *cdb_intr_string = "";
                const char *atapi_an_string = "";
                const char *dma_dir_string = "";
                u32 sntf;

                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;

                /* Enable ATAPI AN if both the host and device have
                 * the support.  If PMP is attached, SNTF is required
                 * to enable ATAPI AN to discern between PHY status
                 * changed notifications and ATAPI ANs.
                 */
                if ((ap->flags & ATA_FLAG_AN) && ata_id_has_atapi_AN(id) &&
                    (!ap->nr_pmp_links ||
                     sata_scr_read(&ap->link, SCR_NOTIFICATION, &sntf) == 0)) {
                        unsigned int err_mask;

                        /* issue SET feature command to turn this on */
                        err_mask = ata_dev_set_feature(dev,
                                        SETFEATURES_SATA_ENABLE, SATA_AN);
                        if (err_mask)
                                ata_dev_printk(dev, KERN_ERR,
                                        "failed to enable ATAPI AN "
                                        "(err_mask=0x%x)\n", err_mask);
                        else {
                                dev->flags |= ATA_DFLAG_AN;
                                atapi_an_string = ", ATAPI AN";
                        }
                }

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

                if (atapi_dmadir || atapi_id_dmadir(dev->id)) {
                        dev->flags |= ATA_DFLAG_DMADIR;
                        dma_dir_string = ", DMADIR";
                }

                /* print device info to dmesg */
                if (ata_msg_drv(ap) && print_info)
                        ata_dev_printk(dev, KERN_INFO,
                                       "ATAPI: %s, %s, max %s%s%s%s\n",
                                       modelbuf, fwrevbuf,
                                       ata_mode_string(xfer_mask),
                                       cdb_intr_string, atapi_an_string,
                                       dma_dir_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_IPM)) {
                if (ata_id_has_hipm(dev->id))
                        dev->flags |= ATA_DFLAG_HIPM;
                if (ata_id_has_dipm(dev->id))
                        dev->flags |= ATA_DFLAG_DIPM;
        }

        /* Limit PATA drive on SATA cable 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 ((dev->class == ATA_DEV_ATAPI) &&
            (atapi_command_packet_set(id) == TYPE_TAPE)) {
                dev->max_sectors = ATA_MAX_SECTORS_TAPE;
                dev->horkage |= ATA_HORKAGE_STUCK_ERR;
        }

        if (dev->horkage & ATA_HORKAGE_MAX_SEC_128)
                dev->max_sectors = min_t(unsigned int, ATA_MAX_SECTORS_128,
                                         dev->max_sectors);

        if (ata_dev_blacklisted(dev) & ATA_HORKAGE_IPM) {
                dev->horkage |= ATA_HORKAGE_IPM;

                /* reset link pm_policy for this port to no pm */
                ap->pm_policy = MAX_PERFORMANCE;
        }

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

        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. Do this after the dev_config call as some controllers
                   with buggy firmware may want to avoid reporting false device
                   bugs */

                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");
                }
        }

        return 0;

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

/**
 *      ata_cable_40wire        -       return 40 wire cable type
 *      @ap: port
 *
 *      Helper method for drivers which want to hardwire 40 wire cable
 *      detection.
 */

int ata_cable_40wire(struct ata_port *ap)
{
        return ATA_CBL_PATA40;
}

/**
 *      ata_cable_80wire        -       return 80 wire cable type
 *      @ap: port
 *
 *      Helper method for drivers which want to hardwire 80 wire cable
 *      detection.
 */

int ata_cable_80wire(struct ata_port *ap)
{
        return ATA_CBL_PATA80;
}

/**
 *      ata_cable_unknown       -       return unknown PATA cable.
 *      @ap: port
 *
 *      Helper method for drivers which have no PATA cable detection.
 */

int ata_cable_unknown(struct ata_port *ap)
{
        return ATA_CBL_PATA_UNK;
}

/**
 *      ata_cable_ignore        -       return ignored PATA cable.
 *      @ap: port
 *
 *      Helper method for drivers which don't use cable type to limit
 *      transfer mode.
 */
int ata_cable_ignore(struct ata_port *ap)
{
        return ATA_CBL_PATA_IGN;
}

/**
 *      ata_cable_sata  -       return SATA cable type
 *      @ap: port
 *
 *      Helper method for drivers which have SATA cables
 */

int ata_cable_sata(struct ata_port *ap)
{
        return ATA_CBL_SATA;
}

/**
 *      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 rc;
        struct ata_device *dev;

        ata_port_probe(ap);

        ata_link_for_each_dev(dev, &ap->link)
                tries[dev->devno] = ATA_PROBE_MAX_TRIES;

 retry:
        ata_link_for_each_dev(dev, &ap->link) {
                /* If we issue an SRST then an ATA drive (not ATAPI)
                 * may change configuration and be in PIO0 timing. If
                 * we do a hard reset (or are coming from power on)
                 * this is true for ATA or ATAPI. Until we've set a
                 * suitable controller mode we should not touch the
                 * bus as we may be talking too fast.
                 */
                dev->pio_mode = XFER_PIO_0;

                /* If the controller has a pio mode setup function
                 * then use it to set the chipset to rights. Don't
                 * touch the DMA setup as that will be dealt with when
                 * configuring devices.
                 */
                if (ap->ops->set_piomode)
                        ap->ops->set_piomode(ap, dev);
        }

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

        ata_link_for_each_dev(dev, &ap->link) {
                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);

        /* read IDENTIFY page and configure devices. We have to do the identify
           specific sequence bass-ackwards so that PDIAG- is released by
           the slave device */

        ata_link_for_each_dev_reverse(dev, &ap->link) {
                if (tries[dev->devno])
                        dev->class = classes[dev->devno];

                if (!ata_dev_enabled(dev))
                        continue;

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

        /* Now ask for the cable type as PDIAG- should have been released */
        if (ap->ops->cable_detect)
                ap->cbl = ap->ops->cable_detect(ap);

        /* We may have SATA bridge glue hiding here irrespective of the
           reported cable types and sensed types */
        ata_link_for_each_dev(dev, &ap->link) {
                if (!ata_dev_enabled(dev))
                        continue;
                /* SATA drives indicate we have a bridge. We don't know which
                   end of the link the bridge is which is a problem */
                if (ata_id_is_sata(dev->id))
                        ap->cbl = ATA_CBL_SATA;
        }

        /* After the identify sequence we can now set up the devices. We do
           this in the normal order so that the user doesn't get confused */

        ata_link_for_each_dev(dev, &ap->link) {
                if (!ata_dev_enabled(dev))
                        continue;

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

        /* configure transfer mode */
        rc = ata_set_mode(&ap->link, &dev);
        if (rc)
                goto fail;

        ata_link_for_each_dev(dev, &ap->link)
                if (ata_dev_enabled(dev))
                        return 0;

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

 fail:
        tries[dev->devno]--;

        switch (rc) {
        case -EINVAL:
                /* eeek, something went very wrong, give up */
                tries[dev->devno] = 0;
                break;

        case -ENODEV:
                /* give it just one more chance */
                tries[dev->devno] = min(tries[dev->devno], 1);
        case -EIO:
                if (tries[dev->devno] == 1) {
                        /* This is the last chance, better to slow
                         * down than lose it.
                         */
                        sata_down_spd_limit(&ap->link);
                        ata_down_xfermask_limit(dev, ATA_DNXFER_PIO);
                }
        }

        if (!tries[dev->devno])
                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
 *      @link: SATA link to printk link status about
 *
 *      This function prints link speed and status of a SATA link.
 *
 *      LOCKING:
 *      None.
 */
void sata_print_link_status(struct ata_link *link)
{
        u32 sstatus, scontrol, tmp;

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

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

/**
 *      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_link *link = adev->link;
        struct ata_device *pair = &link->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->link.device[0].class = ATA_DEV_NONE;
        ap->link.device[1].class = ATA_DEV_NONE;
        ap->flags |= ATA_FLAG_DISABLED;
}

/**
 *      sata_down_spd_limit - adjust SATA spd limit downward
 *      @link: Link to adjust SATA spd limit for
 *
 *      Adjust SATA spd limit of @link 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_link *link)
{
        u32 sstatus, spd, mask;
        int rc, highbit;

        if (!sata_scr_valid(link))
                return -EOPNOTSUPP;

        /* If SCR can be read, use it to determine the current SPD.
         * If not, use cached value in link->sata_spd.
         */
        rc = sata_scr_read(link, SCR_STATUS, &sstatus);
        if (rc == 0)
                spd = (sstatus >> 4) & 0xf;
        else
                spd = link->sata_spd;

        mask = link->sata_spd_limit;
        if (mask <= 1)
                return -EINVAL;

        /* unconditionally mask off the highest bit */
        highbit = fls(mask) - 1;
        mask &= ~(1 << highbit);

        /* Mask off all speeds higher than or equal to the current
         * one.  Force 1.5Gbps if current SPD is not available.
         */
        if (spd > 1)
                mask &= (1 << (spd - 1)) - 1;
        else
                mask &= 1;

        /* were we already at the bottom? */
        if (!mask)
                return -EINVAL;

        link->sata_spd_limit = mask;

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

        return 0;
}

static int __sata_set_spd_needed(struct ata_link *link, u32 *scontrol)
{
        struct ata_link *host_link = &link->ap->link;
        u32 limit, target, spd;

        limit = link->sata_spd_limit;

        /* Don't configure downstream link faster than upstream link.
         * It doesn't speed up anything and some PMPs choke on such
         * configuration.
         */
        if (!ata_is_host_link(link) && host_link->sata_spd)
                limit &= (1 << host_link->sata_spd) - 1;

        if (limit == UINT_MAX)
                target = 0;
        else
                target = fls(limit);

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

        return spd != target;
}

/**
 *      sata_set_spd_needed - is SATA spd configuration needed
 *      @link: Link in question
 *
 *      Test whether the spd limit in SControl matches
 *      @link->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_link *link)
{
        u32 scontrol;

        if (sata_scr_read(link, SCR_CONTROL, &scontrol))
                return 1;

        return __sata_set_spd_needed(link, &scontrol);
}

/**
 *      sata_set_spd - set SATA spd according to spd limit
 *      @link: Link to set SATA spd for
 *
 *      Set SATA spd of @link 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_link *link)
{
        u32 scontrol;
        int rc;

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

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

        if ((rc = sata_scr_write(link, 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_PIO_SLOW, 120, 290, 240, 960, 290, 240, 960,   0 }, */
        { XFER_PIO_0,     70, 290, 240, 600, 165, 150, 600,   0 },
        { XFER_PIO_1,     50, 290,  93, 383, 125, 100, 383,   0 },
        { XFER_PIO_2,     30, 290,  40, 330, 100,  90, 240,   0 },
        { XFER_PIO_3,     30,  80,  70, 180,  80,  70, 180,   0 },
        { XFER_PIO_4,     25,  70,  25, 120,  70,  25, 120,   0 },
        { XFER_PIO_5,     15,  65,  25, 100,  65,  25, 100,   0 },
        { XFER_PIO_6,     10,  55,  20,  80,  55,  20,  80,   0 },

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

        { XFER_MW_DMA_0,  60,   0,   0,   0, 215, 215, 480,   0 },
        { XFER_MW_DMA_1,  45,   0,   0,   0,  80,  50, 150,   0 },
        { XFER_MW_DMA_2,  25,   0,   0,   0,  70,  25, 120,   0 },
        { XFER_MW_DMA_3,  25,   0,   0,   0,  65,  25, 100,   0 },
        { XFER_MW_DMA_4,  25,   0,   0,   0,  55,  20,  80,   0 },

/*      { XFER_UDMA_SLOW,  0,   0,   0,   0,   0,   0,   0, 150 }, */
        { XFER_UDMA_0,     0,   0,   0,   0,   0,   0,   0, 120 },
        { XFER_UDMA_1,     0,   0,   0,   0,   0,   0,   0,  80 },
        { XFER_UDMA_2,     0,   0,   0,   0,   0,   0,   0,  60 },
        { XFER_UDMA_3,     0,   0,   0,   0,   0,   0,   0,  45 },
        { XFER_UDMA_4,     0,   0,   0,   0,   0,   0,   0,  30 },
        { XFER_UDMA_5,     0,   0,   0,   0,   0,   0,   0,  20 },
        { XFER_UDMA_6,     0,   0,   0,   0,   0,   0,   0,  15 },

        { 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);
}

const struct ata_timing *ata_timing_find_mode(u8 xfer_mode)
{
        const struct ata_timing *t = ata_timing;

        while (xfer_mode > t->mode)
                t++;

        if (xfer_mode == t->mode)
                return t;
        return NULL;
}

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;
        }

        /* In a few cases quantisation may produce enough errors to
           leave t->cycle too low for the sum of active and recovery
           if so we must correct this */
        if (t->active + t->recover > t->cycle)
                t->cycle = t->active + t->recover;

        return 0;
}

/**
 *      ata_timing_cycle2mode - find xfer mode for the specified cycle duration
 *      @xfer_shift: ATA_SHIFT_* value for transfer type to examine.
 *      @cycle: cycle duration in ns
 *
 *      Return matching xfer mode for @cycle.  The returned mode is of
 *      the transfer type specified by @xfer_shift.  If @cycle is too
 *      slow for @xfer_shift, 0xff is returned.  If @cycle is faster
 *      than the fastest known mode, the fasted mode is returned.
 *
 *      LOCKING:
 *      None.
 *
 *      RETURNS:
 *      Matching xfer_mode, 0xff if no match found.
 */
u8 ata_timing_cycle2mode(unsigned int xfer_shift, int cycle)
{
        u8 base_mode = 0xff, last_mode = 0xff;
        const struct ata_xfer_ent *ent;
        const struct ata_timing *t;

        for (ent = ata_xfer_tbl; ent->shift >= 0; ent++)
                if (ent->shift == xfer_shift)
                        base_mode = ent->base;

        for (t = ata_timing_find_mode(base_mode);
             t && ata_xfer_mode2shift(t->mode) == xfer_shift; t++) {
                unsigned short this_cycle;

                switch (xfer_shift) {
                case ATA_SHIFT_PIO:
                case ATA_SHIFT_MWDMA:
                        this_cycle = t->cycle;
                        break;
                case ATA_SHIFT_UDMA:
                        this_cycle = t->udma;
                        break;
                default:
                        return 0xff;
                }

                if (cycle > this_cycle)
                        break;

                last_mode = t->mode;
        }

        return last_mode;
}

/**
 *      ata_down_xfermask_limit - adjust dev xfer masks downward
 *      @dev: Device to adjust xfer masks
 *      @sel: ATA_DNXFER_* selector
 *
 *      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, unsigned int sel)
{
        char buf[32];
        unsigned long orig_mask, xfer_mask;
        unsigned long pio_mask, mwdma_mask, udma_mask;
        int quiet, highbit;

        quiet = !!(sel & ATA_DNXFER_QUIET);
        sel &= ~ATA_DNXFER_QUIET;

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

        switch (sel) {
        case ATA_DNXFER_PIO:
                highbit = fls(pio_mask) - 1;
                pio_mask &= ~(1 << highbit);
                break;

        case ATA_DNXFER_DMA:
                if (udma_mask) {
                        highbit = fls(udma_mask) - 1;
                        udma_mask &= ~(1 << highbit);
                        if (!udma_mask)
                                return -ENOENT;
                } else if (mwdma_mask) {
                        highbit = fls(mwdma_mask) - 1;
                        mwdma_mask &= ~(1 << highbit);
                        if (!mwdma_mask)
                                return -ENOENT;
                }
                break;

        case ATA_DNXFER_40C:
                udma_mask &= ATA_UDMA_MASK_40C;
                break;

        case ATA_DNXFER_FORCE_PIO0:
                pio_mask &= 1;
        case ATA_DNXFER_FORCE_PIO:
                mwdma_mask = 0;
                udma_mask = 0;
                break;

        default:
                BUG();
        }

        xfer_mask &= ata_pack_xfermask(pio_mask, mwdma_mask, udma_mask);

        if (!(xfer_mask & ATA_MASK_PIO) || xfer_mask == orig_mask)
                return -ENOENT;

        if (!quiet) {
                if (xfer_mask & (ATA_MASK_MWDMA | ATA_MASK_UDMA))
                        snprintf(buf, sizeof(buf), "%s:%s",
                                 ata_mode_string(xfer_mask),
                                 ata_mode_string(xfer_mask & ATA_MASK_PIO));
                else
                        snprintf(buf, sizeof(buf), "%s",
                                 ata_mode_string(xfer_mask));

                ata_dev_printk(dev, KERN_WARNING,
                               "limiting speed to %s\n", buf);
        }

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

        return 0;
}

static int ata_dev_set_mode(struct ata_device *dev)
{
        struct ata_eh_context *ehc = &dev->link->eh_context;
        const char *dev_err_whine = "";
        int ign_dev_err = 0;
        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 & ~AC_ERR_DEV)
                goto fail;

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

        /* Old CFA may refuse this command, which is just fine */
        if (dev->xfer_shift == ATA_SHIFT_PIO && ata_id_is_cfa(dev->id))
                ign_dev_err = 1;

        /* Some very old devices and some bad newer ones fail any kind of
           SET_XFERMODE request but support PIO0-2 timings and no IORDY */
        if (dev->xfer_shift == ATA_SHIFT_PIO && !ata_id_has_iordy(dev->id) &&
                        dev->pio_mode <= XFER_PIO_2)
                ign_dev_err = 1;

        /* Early MWDMA devices do DMA but don't allow DMA mode setting.
           Don't fail an MWDMA0 set IFF the device indicates it is in MWDMA0 */
        if (dev->xfer_shift == ATA_SHIFT_MWDMA &&
            dev->dma_mode == XFER_MW_DMA_0 &&
            (dev->id[63] >> 8) & 1)
                ign_dev_err = 1;

        /* if the device is actually configured correctly, ignore dev err */
        if (dev->xfer_mode == ata_xfer_mask2mode(ata_id_xfermask(dev->id)))
                ign_dev_err = 1;

        if (err_mask & AC_ERR_DEV) {
                if (!ign_dev_err)
                        goto fail;
                else
                        dev_err_whine = " (device error ignored)";
        }

        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%s\n",
                       ata_mode_string(ata_xfer_mode2mask(dev->xfer_mode)),
                       dev_err_whine);

        return 0;

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

/**
 *      ata_do_set_mode - Program timings and issue SET FEATURES - XFER
 *      @link: link on which timings will be programmed
 *      @r_failed_dev: out parameter for failed device
 *
 *      Standard implementation of the function used to tune and set
 *      ATA device disk transfer mode (PIO3, UDMA6, etc.).  If
 *      ata_dev_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_do_set_mode(struct ata_link *link, struct ata_device **r_failed_dev)
{
        struct ata_port *ap = link->ap;
        struct ata_device *dev;
        int rc = 0, used_dma = 0, found = 0;

        /* step 1: calculate xfer_mask */
        ata_link_for_each_dev(dev, link) {
                unsigned long pio_mask, dma_mask;
                unsigned int mode_mask;

                if (!ata_dev_enabled(dev))
                        continue;

                mode_mask = ATA_DMA_MASK_ATA;
                if (dev->class == ATA_DEV_ATAPI)
                        mode_mask = ATA_DMA_MASK_ATAPI;
                else if (ata_id_is_cfa(dev->id))
                        mode_mask = ATA_DMA_MASK_CFA;

                ata_dev_xfermask(dev);
                ata_force_xfermask(dev);

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

                if (libata_dma_mask & mode_mask)
                        dma_mask = ata_pack_xfermask(0, dev->mwdma_mask, dev->udma_mask);
                else
                        dma_mask = 0;

                dev->pio_mode = ata_xfer_mask2mode(pio_mask);
                dev->dma_mode = ata_xfer_mask2mode(dma_mask);

                found = 1;
                if (dev->dma_mode != 0xff)
                        used_dma = 1;
        }
        if (!found)
                goto out;

        /* step 2: always set host PIO timings */
        ata_link_for_each_dev(dev, link) {
                if (!ata_dev_enabled(dev))
                        continue;

                if (dev->pio_mode == 0xff) {
                        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 */
        ata_link_for_each_dev(dev, link) {
                if (!ata_dev_enabled(dev) || dev->dma_mode == 0xff)
                        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 */
        ata_link_for_each_dev(dev, link) {
                /* don't update suspended devices' xfer mode */
                if (!ata_dev_enabled(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 = ap;

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

/**
 *      ata_wait_ready - wait for link to become ready
 *      @link: link to be waited on
 *      @deadline: deadline jiffies for the operation
 *      @check_ready: callback to check link readiness
 *
 *      Wait for @link to become ready.  @check_ready should return
 *      positive number if @link is ready, 0 if it isn't, -ENODEV if
 *      link doesn't seem to be occupied, other errno for other error
 *      conditions.
 *
 *      Transient -ENODEV conditions are allowed for
 *      ATA_TMOUT_FF_WAIT.
 *
 *      LOCKING:
 *      EH context.
 *
 *      RETURNS:
 *      0 if @linke is ready before @deadline; otherwise, -errno.
 */
int ata_wait_ready(struct ata_link *link, unsigned long deadline,
                   int (*check_ready)(struct ata_link *link))
{
        unsigned long start = jiffies;
        unsigned long nodev_deadline = start + ATA_TMOUT_FF_WAIT;
        int warned = 0;

        if (time_after(nodev_deadline, deadline))
                nodev_deadline = deadline;

        while (1) {
                unsigned long now = jiffies;
                int ready, tmp;

                ready = tmp = check_ready(link);
                if (ready > 0)
                        return 0;

                /* -ENODEV could be transient.  Ignore -ENODEV if link
                 * is online.  Also, some SATA devices take a long
                 * time to clear 0xff after reset.  For example,
                 * HHD424020F7SV00 iVDR needs >= 800ms while Quantum
                 * GoVault needs even more than that.  Wait for
                 * ATA_TMOUT_FF_WAIT on -ENODEV if link isn't offline.
                 *
                 * Note that some PATA controllers (pata_ali) explode
                 * if status register is read more than once when
                 * there's no device attached.
                 */
                if (ready == -ENODEV) {
                        if (ata_link_online(link))
                                ready = 0;
                        else if ((link->ap->flags & ATA_FLAG_SATA) &&
                                 !ata_link_offline(link) &&
                                 time_before(now, nodev_deadline))
                                ready = 0;
                }

                if (ready)
                        return ready;
                if (time_after(now, deadline))
                        return -EBUSY;

                if (!warned && time_after(now, start + 5 * HZ) &&
                    (deadline - now > 3 * HZ)) {
                        ata_link_printk(link, KERN_WARNING,
                                "link is slow to respond, please be patient "
                                "(ready=%d)\n", tmp);
                        warned = 1;
                }

                msleep(50);
        }
}

/**
 *      ata_wait_after_reset - wait for link to become ready after reset
 *      @link: link to be waited on
 *      @deadline: deadline jiffies for the operation
 *      @check_ready: callback to check link readiness
 *
 *      Wait for @link to become ready after reset.
 *
 *      LOCKING:
 *      EH context.
 *
 *      RETURNS:
 *      0 if @linke is ready before @deadline; otherwise, -errno.
 */
extern int ata_wait_after_reset(struct ata_link *link, unsigned long deadline,
                                int (*check_ready)(struct ata_link *link))
{
        msleep(ATA_WAIT_AFTER_RESET_MSECS);

        return ata_wait_ready(link, deadline, check_ready);
}

/**
 *      sata_link_debounce - debounce SATA phy status
 *      @link: ATA link to debounce SATA phy status for
 *      @params: timing parameters { interval, duratinon, timeout } in msec
 *      @deadline: deadline jiffies for the operation
 *
*       Make sure SStatus of @link 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 DET gets stuck at 1 on
 *      some controllers after hot unplugging, this functions waits
 *      until timeout then returns 0 if DET is stable at 1.
 *
 *      @timeout is further limited by @deadline.  The sooner of the
 *      two is used.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep)
 *
 *      RETURNS:
 *      0 on success, -errno on failure.
 */
int sata_link_debounce(struct ata_link *link, const unsigned long *params,
                       unsigned long deadline)
{
        unsigned long interval_msec = params[0];
        unsigned long duration = msecs_to_jiffies(params[1]);
        unsigned long last_jiffies, t;
        u32 last, cur;
        int rc;

        t = jiffies + msecs_to_jiffies(params[2]);
        if (time_before(t, deadline))
                deadline = t;

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

        last = cur;
        last_jiffies = jiffies;

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

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

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

                /* Check deadline.  If debouncing failed, return
                 * -EPIPE to tell upper layer to lower link speed.
                 */
                if (time_after(jiffies, deadline))
                        return -EPIPE;
        }
}

/**
 *      sata_link_resume - resume SATA link
 *      @link: ATA link to resume SATA
 *      @params: timing parameters { interval, duratinon, timeout } in msec
 *      @deadline: deadline jiffies for the operation
 *
 *      Resume SATA phy @link and debounce it.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep)
 *
 *      RETURNS:
 *      0 on success, -errno on failure.
 */
int sata_link_resume(struct ata_link *link, const unsigned long *params,
                     unsigned long deadline)
{
        u32 scontrol, serror;
        int rc;

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

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

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

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

        if ((rc = sata_link_debounce(link, params, deadline)))
                return rc;

        /* Clear SError.  PMP and some host PHYs require this to
         * operate and clearing should be done before checking PHY
         * online status to avoid race condition (hotplugging between
         * link resume and status check).
         */
        if (!(rc = sata_scr_read(link, SCR_ERROR, &serror)))
                rc = sata_scr_write(link, SCR_ERROR, serror);
        if (rc == 0 || rc == -EINVAL) {
                unsigned long flags;

                spin_lock_irqsave(link->ap->lock, flags);
                link->eh_info.serror = 0;
                spin_unlock_irqrestore(link->ap->lock, flags);
                rc = 0;
        }
        return rc;
}

/**
 *      ata_std_prereset - prepare for reset
 *      @link: ATA link to be reset
 *      @deadline: deadline jiffies for the operation
 *
 *      @link is about to be reset.  Initialize it.  Failure from
 *      prereset makes libata abort whole reset sequence and give up
 *      that port, so prereset should be best-effort.  It does its
 *      best to prepare for reset sequence but if things go wrong, it
 *      should just whine, not fail.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep)
 *
 *      RETURNS:
 *      0 on success, -errno otherwise.
 */
int ata_std_prereset(struct ata_link *link, unsigned long deadline)
{
        struct ata_port *ap = link->ap;
        struct ata_eh_context *ehc = &link->eh_context;
        const unsigned long *timing = sata_ehc_deb_timing(ehc);
        int rc;

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

        /* if SATA, resume link */
        if (ap->flags & ATA_FLAG_SATA) {
                rc = sata_link_resume(link, timing, deadline);
                /* whine about phy resume failure but proceed */
                if (rc && rc != -EOPNOTSUPP)
                        ata_link_printk(link, KERN_WARNING, "failed to resume "
                                        "link for reset (errno=%d)\n", rc);
        }

        return 0;
}

/**
 *      sata_link_hardreset - reset link via SATA phy reset
 *      @link: link to reset
 *      @timing: timing parameters { interval, duratinon, timeout } in msec
 *      @deadline: deadline jiffies for the operation
 *      @online: optional out parameter indicating link onlineness
 *      @check_ready: optional callback to check link readiness
 *
 *      SATA phy-reset @link using DET bits of SControl register.
 *      After hardreset, link readiness is waited upon using
 *      ata_wait_ready() if @check_ready is specified.  LLDs are
 *      allowed to not specify @check_ready and wait itself after this
 *      function returns.  Device classification is LLD's
 *      responsibility.
 *
 *      *@online is set to one iff reset succeeded and @link is online
 *      after reset.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep)
 *
 *      RETURNS:
 *      0 on success, -errno otherwise.
 */
int sata_link_hardreset(struct ata_link *link, const unsigned long *timing,
                        unsigned long deadline,
                        bool *online, int (*check_ready)(struct ata_link *))
{
        u32 scontrol;
        int rc;

        DPRINTK("ENTER\n");

        if (online)
                *online = false;

        if (sata_set_spd_needed(link)) {
                /* 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(link, SCR_CONTROL, &scontrol)))
                        goto out;

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

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

                sata_set_spd(link);
        }

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

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

        if ((rc = sata_scr_write_flush(link, 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 link back */
        rc = sata_link_resume(link, timing, deadline);
        if (rc)
                goto out;
        /* if link is offline nothing more to do */
        if (ata_link_offline(link))
                goto out;

        /* Link is online.  From this point, -ENODEV too is an error. */
        if (online)
                *online = true;

        if ((link->ap->flags & ATA_FLAG_PMP) && ata_is_host_link(link)) {
                /* If PMP is supported, we have to do follow-up SRST.
                 * Some PMPs don't send D2H Reg FIS after hardreset if
                 * the first port is empty.  Wait only for
                 * ATA_TMOUT_PMP_SRST_WAIT.
                 */
                if (check_ready) {
                        unsigned long pmp_deadline;

                        pmp_deadline = jiffies + ATA_TMOUT_PMP_SRST_WAIT;
                        if (time_after(pmp_deadline, deadline))
                                pmp_deadline = deadline;
                        ata_wait_ready(link, pmp_deadline, check_ready);
                }
                rc = -EAGAIN;
                goto out;
        }

        rc = 0;
        if (check_ready)
                rc = ata_wait_ready(link, deadline, check_ready);
 out:
        if (rc && rc != -EAGAIN)
                ata_link_printk(link, KERN_ERR,
                                "COMRESET failed (errno=%d)\n", rc);
        DPRINTK("EXIT, rc=%d\n", rc);
        return rc;
}

/**
 *      sata_std_hardreset - COMRESET w/o waiting or classification
 *      @link: link to reset
 *      @class: resulting class of attached device
 *      @deadline: deadline jiffies for the operation
 *
 *      Standard SATA COMRESET w/o waiting or classification.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep)
 *
 *      RETURNS:
 *      0 if link offline, -EAGAIN if link online, -errno on errors.
 */
int sata_std_hardreset(struct ata_link *link, unsigned int *class,
                       unsigned long deadline)
{
        const unsigned long *timing = sata_ehc_deb_timing(&link->eh_context);
        bool online;
        int rc;

        /* do hardreset */
        rc = sata_link_hardreset(link, timing, deadline, &online, NULL);
        return online ? -EAGAIN : rc;
}

/**
 *      ata_std_postreset - standard postreset callback
 *      @link: the target ata_link
 *      @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_link *link, unsigned int *classes)
{
        DPRINTK("ENTER\n");

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

        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][ATA_ID_PROD_LEN + 1];
        unsigned char serial[2][ATA_ID_SERNO_LEN + 1];

        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, sizeof(model[0]));
        ata_id_c_string(new_id, model[1], ATA_ID_PROD, sizeof(model[1]));
        ata_id_c_string(old_id, serial[0], ATA_ID_SERNO, sizeof(serial[0]));
        ata_id_c_string(new_id, serial[1], ATA_ID_SERNO, sizeof(serial[1]));

        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;
        }

        return 1;
}

/**
 *      ata_dev_reread_id - Re-read IDENTIFY data
 *      @dev: target ATA device
 *      @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_reread_id(struct ata_device *dev, unsigned int readid_flags)
{
        unsigned int class = dev->class;
        u16 *id = (void *)dev->link->ap->sector_buf;
        int rc;

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

        /* is the device still there? */
        if (!ata_dev_same_device(dev, class, id))
                return -ENODEV;

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

/**
 *      ata_dev_revalidate - Revalidate ATA device
 *      @dev: device to revalidate
 *      @new_class: new class code
 *      @readid_flags: read ID flags
 *
 *      Re-read IDENTIFY page, make sure @dev is still attached to the
 *      port and reconfigure it according to the new IDENTIFY page.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep)
 *
 *      RETURNS:
 *      0 on success, negative errno otherwise
 */
int ata_dev_revalidate(struct ata_device *dev, unsigned int new_class,
                       unsigned int readid_flags)
{
        u64 n_sectors = dev->n_sectors;
        int rc;

        if (!ata_dev_enabled(dev))
                return -ENODEV;

        /* fail early if !ATA && !ATAPI to avoid issuing [P]IDENTIFY to PMP */
        if (ata_class_enabled(new_class) &&
            new_class != ATA_DEV_ATA && new_class != ATA_DEV_ATAPI) {
                ata_dev_printk(dev, KERN_INFO, "class mismatch %u != %u\n",
                               dev->class, new_class);
                rc = -ENODEV;
                goto fail;
        }

        /* re-read ID */
        rc = ata_dev_reread_id(dev, readid_flags);
        if (rc)
                goto fail;

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

        /* verify n_sectors hasn't changed */
        if (dev->class == ATA_DEV_ATA && n_sectors &&
            dev->n_sectors != n_sectors) {
                ata_dev_printk(dev, KERN_INFO, "n_sectors mismatch "
                               "%llu != %llu\n",
                               (unsigned long long)n_sectors,
                               (unsigned long long)dev->n_sectors);

                /* restore original n_sectors */
                dev->n_sectors = n_sectors;

                rc = -ENODEV;
                goto fail;
        }

        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 },
        { "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 },
        { "Seagate STT20000A", NULL,            ATA_HORKAGE_NODMA },
        /* Odd clown on sil3726/4726 PMPs */
        { "Config  Disk",       NULL,           ATA_HORKAGE_NODMA |
                                                ATA_HORKAGE_SKIP_PM },

        /* Weird ATAPI devices */
        { "TORiSAN DVD-ROM DRD-N216", NULL,     ATA_HORKAGE_MAX_SEC_128 },

        /* Devices we expect to fail diagnostics */

        /* Devices where NCQ should be avoided */
        /* NCQ is slow */
        { "WDC WD740ADFD-00",   NULL,           ATA_HORKAGE_NONCQ },
        { "WDC WD740ADFD-00NLR1", NULL,         ATA_HORKAGE_NONCQ, },
        /* http://thread.gmane.org/gmane.linux.ide/14907 */
        { "FUJITSU MHT2060BH",  NULL,           ATA_HORKAGE_NONCQ },
        /* NCQ is broken */
        { "Maxtor *",           "BANC*",        ATA_HORKAGE_NONCQ },
        { "Maxtor 7V300F0",     "VA111630",     ATA_HORKAGE_NONCQ },
        { "ST380817AS",         "3.42",         ATA_HORKAGE_NONCQ },
        { "ST3160023AS",        "3.42",         ATA_HORKAGE_NONCQ },

        /* Blacklist entries taken from Silicon Image 3124/3132
           Windows driver .inf file - also several Linux problem reports */
        { "HTS541060G9SA00",    "MB3OC60D",     ATA_HORKAGE_NONCQ, },
        { "HTS541080G9SA00",    "MB4OC60D",     ATA_HORKAGE_NONCQ, },
        { "HTS541010G9SA00",    "MBZOC60D",     ATA_HORKAGE_NONCQ, },

        /* devices which puke on READ_NATIVE_MAX */
        { "HDS724040KLSA80",    "KFAOA20N",     ATA_HORKAGE_BROKEN_HPA, },
        { "WDC WD3200JD-00KLB0", "WD-WCAMR1130137", ATA_HORKAGE_BROKEN_HPA },
        { "WDC WD2500JD-00HBB0", "WD-WMAL71490727", ATA_HORKAGE_BROKEN_HPA },
        { "MAXTOR 6L080L4",     "A93.0500",     ATA_HORKAGE_BROKEN_HPA },

        /* Devices which report 1 sector over size HPA */
        { "ST340823A",          NULL,           ATA_HORKAGE_HPA_SIZE, },
        { "ST320413A",          NULL,           ATA_HORKAGE_HPA_SIZE, },
        { "ST310211A",          NULL,           ATA_HORKAGE_HPA_SIZE, },

        /* Devices which get the IVB wrong */
        { "QUANTUM FIREBALLlct10 05", "A03.0900", ATA_HORKAGE_IVB, },
        { "TSSTcorp CDDVDW SH-S202J", "SB00",     ATA_HORKAGE_IVB, },
        { "TSSTcorp CDDVDW SH-S202J", "SB01",     ATA_HORKAGE_IVB, },
        { "TSSTcorp CDDVDW SH-S202N", "SB00",     ATA_HORKAGE_IVB, },
        { "TSSTcorp CDDVDW SH-S202N", "SB01",     ATA_HORKAGE_IVB, },

        /* End Marker */
        { }
};

static int strn_pattern_cmp(const char *patt, const char *name, int wildchar)
{
        const char *p;
        int len;

        /*
         * check for trailing wildcard: *\0
         */
        p = strchr(patt, wildchar);
        if (p && ((*(p + 1)) == 0))
                len = p - patt;
        else {
                len = strlen(name);
                if (!len) {
                        if (!*patt)
                                return 0;
                        return -1;
                }
        }

        return strncmp(patt, name, len);
}

static unsigned long ata_dev_blacklisted(const struct ata_device *dev)
{
        unsigned char model_num[ATA_ID_PROD_LEN + 1];
        unsigned char model_rev[ATA_ID_FW_REV_LEN + 1];
        const struct ata_blacklist_entry *ad = ata_device_blacklist;

        ata_id_c_string(dev->id, model_num, ATA_ID_PROD, sizeof(model_num));
        ata_id_c_string(dev->id, model_rev, ATA_ID_FW_REV, sizeof(model_rev));

        while (ad->model_num) {
                if (!strn_pattern_cmp(ad->model_num, model_num, '*')) {
                        if (ad->model_rev == NULL)
                                return ad->horkage;
                        if (!strn_pattern_cmp(ad->model_rev, model_rev, '*'))
                                return ad->horkage;
                }
                ad++;
        }
        return 0;
}

static int ata_dma_blacklisted(const struct ata_device *dev)
{
        /* We don't support polling DMA.
         * DMA blacklist those ATAPI devices with CDB-intr (and use PIO)
         * if the LLDD handles only interrupts in the HSM_ST_LAST state.
         */
        if ((dev->link->ap->flags & ATA_FLAG_PIO_POLLING) &&
            (dev->flags & ATA_DFLAG_CDB_INTR))
                return 1;
        return (dev->horkage & ATA_HORKAGE_NODMA) ? 1 : 0;
}

/**
 *      ata_is_40wire           -       check drive side detection
 *      @dev: device
 *
 *      Perform drive side detection decoding, allowing for device vendors
 *      who can't follow the documentation.
 */

static int ata_is_40wire(struct ata_device *dev)
{
        if (dev->horkage & ATA_HORKAGE_IVB)
                return ata_drive_40wire_relaxed(dev->id);
        return ata_drive_40wire(dev->id);
}

/**
 *      cable_is_40wire         -       40/80/SATA decider
 *      @ap: port to consider
 *
 *      This function encapsulates the policy for speed management
 *      in one place. At the moment we don't cache the result but
 *      there is a good case for setting ap->cbl to the result when
 *      we are called with unknown cables (and figuring out if it
 *      impacts hotplug at all).
 *
 *      Return 1 if the cable appears to be 40 wire.
 */

static int cable_is_40wire(struct ata_port *ap)
{
        struct ata_link *link;
        struct ata_device *dev;

        /* If the controller thinks we are 40 wire, we are */
        if (ap->cbl == ATA_CBL_PATA40)
                return 1;
        /* If the controller thinks we are 80 wire, we are */
        if (ap->cbl == ATA_CBL_PATA80 || ap->cbl == ATA_CBL_SATA)
                return 0;
        /* If the controller doesn't know we scan

           - Note: We look for all 40 wire detects at this point.
             Any 80 wire detect is taken to be 80 wire cable
             because
             - In many setups only the one drive (slave if present)
               will give a valid detect
             - If you have a non detect capable drive you don't
               want it to colour the choice
        */
        ata_port_for_each_link(link, ap) {
                ata_link_for_each_dev(dev, link) {
                        if (!ata_is_40wire(dev))
                                return 0;
                }
        }
        return 1;
}

/**
 *      ata_dev_xfermask - Compute supported xfermask of the given device
 *      @dev: Device to compute xfermask for
 *
 *      Compute supported xfermask of @dev and store it in
 *      dev->*_mask.  This function is responsible for applying all
 *      known limits including host controller limits, device
 *      blacklist, etc...
 *
 *      LOCKING:
 *      None.
 */
static void ata_dev_xfermask(struct ata_device *dev)
{
        struct ata_link *link = dev->link;
        struct ata_port *ap = link->ap;
        struct ata_host *host = ap->host;
        unsigned long xfer_mask;

        /* controller modes available */
        xfer_mask = ata_pack_xfermask(ap->pio_mask,
                                      ap->mwdma_mask, ap->udma_mask);

        /* drive modes available */
        xfer_mask &= ata_pack_xfermask(dev->pio_mask,
                                       dev->mwdma_mask, dev->udma_mask);
        xfer_mask &= ata_id_xfermask(dev->id);

        /*
         *      CFA Advanced TrueIDE timings are not allowed on a shared
         *      cable
         */
        if (ata_dev_pair(dev)) {
                /* No PIO5 or PIO6 */
                xfer_mask &= ~(0x03 << (ATA_SHIFT_PIO + 5));
                /* No MWDMA3 or MWDMA 4 */
                xfer_mask &= ~(0x03 << (ATA_SHIFT_MWDMA + 3));
        }

        if (ata_dma_blacklisted(dev)) {
                xfer_mask &= ~(ATA_MASK_MWDMA | ATA_MASK_UDMA);
                ata_dev_printk(dev, KERN_WARNING,
                               "device is on DMA blacklist, disabling DMA\n");
        }

        if ((host->flags & ATA_HOST_SIMPLEX) &&
            host->simplex_claimed && host->simplex_claimed != ap) {
                xfer_mask &= ~(ATA_MASK_MWDMA | ATA_MASK_UDMA);
                ata_dev_printk(dev, KERN_WARNING, "simplex DMA is claimed by "
                               "other device, disabling DMA\n");
        }

        if (ap->flags & ATA_FLAG_NO_IORDY)
                xfer_mask &= ata_pio_mask_no_iordy(dev);

        if (ap->ops->mode_filter)
                xfer_mask = ap->ops->mode_filter(dev, xfer_mask);

        /* Apply cable rule here.  Don't apply it early because when
         * we handle hot plug the cable type can itself change.
         * Check this last so that we know if the transfer rate was
         * solely limited by the cable.
         * Unknown or 80 wire cables reported host side are checked
         * drive side as well. Cases where we know a 40wire cable
         * is used safely for 80 are not checked here.
         */
        if (xfer_mask & (0xF8 << ATA_SHIFT_UDMA))
                /* UDMA/44 or higher would be available */
                if (cable_is_40wire(ap)) {
                        ata_dev_printk(dev, KERN_WARNING,
                                 "limited to UDMA/33 due to 40-wire cable\n");
                        xfer_mask &= ~(0xF8 << ATA_SHIFT_UDMA);
                }

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

/**
 *      ata_dev_set_xfermode - Issue SET FEATURES - XFER MODE command
 *      @dev: Device to which command will be sent
 *
 *      Issue SET FEATURES - XFER MODE command to device @dev
 *      on port @ap.
 *
 *      LOCKING:
 *      PCI/etc. bus probe sem.
 *
 *      RETURNS:
 *      0 on success, AC_ERR_* mask otherwise.
 */

static unsigned int ata_dev_set_xfermode(struct ata_device *dev)
{
        struct ata_taskfile tf;
        unsigned int err_mask;

        /* set up set-features taskfile */
        DPRINTK("set features - xfer mode\n");

        /* Some controllers and ATAPI devices show flaky interrupt
         * behavior after setting xfer mode.  Use polling instead.
         */
        ata_tf_init(dev, &tf);
        tf.command = ATA_CMD_SET_FEATURES;
        tf.feature = SETFEATURES_XFER;
        tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE | ATA_TFLAG_POLLING;
        tf.protocol = ATA_PROT_NODATA;
        /* If we are using IORDY we must send the mode setting command */
        if (ata_pio_need_iordy(dev))
                tf.nsect = dev->xfer_mode;
        /* If the device has IORDY and the controller does not - turn it off */
        else if (ata_id_has_iordy(dev->id))
                tf.nsect = 0x01;
        else /* In the ancient relic department - skip all of this */
                return 0;

        err_mask = ata_exec_internal(dev, &tf, NULL, DMA_NONE, NULL, 0, 0);

        DPRINTK("EXIT, err_mask=%x\n", err_mask);
        return err_mask;
}
/**
 *      ata_dev_set_feature - Issue SET FEATURES - SATA FEATURES
 *      @dev: Device to which command will be sent
 *      @enable: Whether to enable or disable the feature
 *      @feature: The sector count represents the feature to set
 *
 *      Issue SET FEATURES - SATA FEATURES command to device @dev
 *      on port @ap with sector count
 *
 *      LOCKING:
 *      PCI/etc. bus probe sem.
 *
 *      RETURNS:
 *      0 on success, AC_ERR_* mask otherwise.
 */
static unsigned int ata_dev_set_feature(struct ata_device *dev, u8 enable,
                                        u8 feature)
{
        struct ata_taskfile tf;
        unsigned int err_mask;

        /* set up set-features taskfile */
        DPRINTK("set features - SATA features\n");

        ata_tf_init(dev, &tf);
        tf.command = ATA_CMD_SET_FEATURES;
        tf.feature = enable;
        tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
        tf.protocol = ATA_PROT_NODATA;
        tf.nsect = feature;

        err_mask = ata_exec_internal(dev, &tf, NULL, DMA_NONE, NULL, 0, 0);

        DPRINTK("EXIT, err_mask=%x\n", err_mask);
        return err_mask;
}

/**
 *      ata_dev_init_params - Issue INIT DEV PARAMS command
 *      @dev: Device to which command will be sent
 *      @heads: Number of heads (taskfile parameter)
 *      @sectors: Number of sectors (taskfile parameter)
 *
 *      LOCKING:
 *      Kernel thread context (may sleep)
 *
 *      RETURNS:
 *      0 on success, AC_ERR_* mask otherwise.
 */
static unsigned int ata_dev_init_params(struct ata_device *dev,
                                        u16 heads, u16 sectors)
{
        struct ata_taskfile tf;
        unsigned int err_mask;

        /* Number of sectors per track 1-255. Number of heads 1-16 */
        if (sectors < 1 || sectors > 255 || heads < 1 || heads > 16)
                return AC_ERR_INVALID;

        /* set up init dev params taskfile */
        DPRINTK("init dev params \n");

        ata_tf_init(dev, &tf);
        tf.command = ATA_CMD_INIT_DEV_PARAMS;
        tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
        tf.protocol = ATA_PROT_NODATA;
        tf.nsect = sectors;
        tf.device |= (heads - 1) & 0x0f; /* max head = num. of heads - 1 */

        err_mask = ata_exec_internal(dev, &tf, NULL, DMA_NONE, NULL, 0, 0);
        /* A clean abort indicates an original or just out of spec drive
           and we should continue as we issue the setup based on the
           drive reported working geometry */
        if (err_mask == AC_ERR_DEV && (tf.feature & ATA_ABORTED))
                err_mask = 0;

        DPRINTK("EXIT, err_mask=%x\n", err_mask);
        return err_mask;
}

/**
 *      ata_sg_clean - Unmap DMA memory associated with command
 *      @qc: Command containing DMA memory to be released
 *
 *      Unmap all mapped DMA memory associated with this command.
 *
 *      LOCKING:
 *      spin_lock_irqsave(host lock)
 */
void ata_sg_clean(struct ata_queued_cmd *qc)
{
        struct ata_port *ap = qc->ap;
        struct scatterlist *sg = qc->sg;
        int dir = qc->dma_dir;

        WARN_ON(sg == NULL);

        VPRINTK("unmapping %u sg elements\n", qc->n_elem);

        if (qc->n_elem)
                dma_unmap_sg(ap->dev, sg, qc->n_elem, dir);

        qc->flags &= ~ATA_QCFLAG_DMAMAP;
        qc->sg = NULL;
}

/**
 *      ata_check_atapi_dma - Check whether ATAPI DMA can be supported
 *      @qc: Metadata associated with taskfile to check
 *
 *      Allow low-level driver to filter ATA PACKET commands, returning
 *      a status indicating whether or not it is OK to use DMA for the
 *      supplied PACKET command.
 *
 *      LOCKING:
 *      spin_lock_irqsave(host lock)
 *
 *      RETURNS: 0 when ATAPI DMA can be used
 *               nonzero otherwise
 */
int ata_check_atapi_dma(struct ata_queued_cmd *qc)
{
        struct ata_port *ap = qc->ap;

        /* Don't allow DMA if it isn't multiple of 16 bytes.  Quite a
         * few ATAPI devices choke on such DMA requests.
         */
        if (unlikely(qc->nbytes & 15))
                return 1;

        if (ap->ops->check_atapi_dma)
                return ap->ops->check_atapi_dma(qc);

        return 0;
}

/**
 *      ata_std_qc_defer - Check whether a qc needs to be deferred
 *      @qc: ATA command in question
 *
 *      Non-NCQ commands cannot run with any other command, NCQ or
 *      not.  As upper layer only knows the queue depth, we are
 *      responsible for maintaining exclusion.  This function checks
 *      whether a new command @qc can be issued.
 *
 *      LOCKING:
 *      spin_lock_irqsave(host lock)
 *
 *      RETURNS:
 *      ATA_DEFER_* if deferring is needed, 0 otherwise.
 */
int ata_std_qc_defer(struct ata_queued_cmd *qc)
{
        struct ata_link *link = qc->dev->link;

        if (qc->tf.protocol == ATA_PROT_NCQ) {
                if (!ata_tag_valid(link->active_tag))
                        return 0;
        } else {
                if (!ata_tag_valid(link->active_tag) && !link->sactive)
                        return 0;
        }

        return ATA_DEFER_LINK;
}

void ata_noop_qc_prep(struct ata_queued_cmd *qc) { }

/**
 *      ata_sg_init - Associate command with scatter-gather table.
 *      @qc: Command to be associated
 *      @sg: Scatter-gather table.
 *      @n_elem: Number of elements in s/g table.
 *
 *      Initialize the data-related elements of queued_cmd @qc
 *      to point to a scatter-gather table @sg, containing @n_elem
 *      elements.
 *
 *      LOCKING:
 *      spin_lock_irqsave(host lock)
 */
void ata_sg_init(struct ata_queued_cmd *qc, struct scatterlist *sg,
                 unsigned int n_elem)
{
        qc->sg = sg;
        qc->n_elem = n_elem;
        qc->cursg = qc->sg;
}

/**
 *      ata_sg_setup - DMA-map the scatter-gather table associated with a command.
 *      @qc: Command with scatter-gather table to be mapped.
 *
 *      DMA-map the scatter-gather table associated with queued_cmd @qc.
 *
 *      LOCKING:
 *      spin_lock_irqsave(host lock)
 *
 *      RETURNS:
 *      Zero on success, negative on error.
 *
 */
static int ata_sg_setup(struct ata_queued_cmd *qc)
{
        struct ata_port *ap = qc->ap;
        unsigned int n_elem;

        VPRINTK("ENTER, ata%u\n", ap->print_id);

        n_elem = dma_map_sg(ap->dev, qc->sg, qc->n_elem, qc->dma_dir);
        if (n_elem < 1)
                return -1;

        DPRINTK("%d sg elements mapped\n", n_elem);

        qc->n_elem = n_elem;
        qc->flags |= ATA_QCFLAG_DMAMAP;

        return 0;
}

/**
 *      swap_buf_le16 - swap halves of 16-bit words in place
 *      @buf:  Buffer to swap
 *      @buf_words:  Number of 16-bit words in buffer.
 *
 *      Swap halves of 16-bit words if needed to convert from
 *      little-endian byte order to native cpu byte order, or
 *      vice-versa.
 *
 *      LOCKING:
 *      Inherited from caller.
 */
void swap_buf_le16(u16 *buf, unsigned int buf_words)
{
#ifdef __BIG_ENDIAN
        unsigned int i;

        for (i = 0; i < buf_words; i++)
                buf[i] = le16_to_cpu(buf[i]);
#endif /* __BIG_ENDIAN */
}

/**
 *      ata_qc_new - Request an available ATA command, for queueing
 *      @ap: Port associated with device @dev
 *      @dev: Device from whom we request an available command structure
 *
 *      LOCKING:
 *      None.
 */

static struct ata_queued_cmd *ata_qc_new(struct ata_port *ap)
{
        struct ata_queued_cmd *qc = NULL;
        unsigned int i;

        /* no command while frozen */
        if (unlikely(ap->pflags & ATA_PFLAG_FROZEN))
                return NULL;

        /* the last tag is reserved for internal command. */
        for (i = 0; i < ATA_MAX_QUEUE - 1; i++)
                if (!test_and_set_bit(i, &ap->qc_allocated)) {
                        qc = __ata_qc_from_tag(ap, i);
                        break;
                }

        if (qc)
                qc->tag = i;

        return qc;
}

/**
 *      ata_qc_new_init - Request an available ATA command, and initialize it
 *      @dev: Device from whom we request an available command structure
 *
 *      LOCKING:
 *      None.
 */

struct ata_queued_cmd *ata_qc_new_init(struct ata_device *dev)
{
        struct ata_port *ap = dev->link->ap;
        struct ata_queued_cmd *qc;

        qc = ata_qc_new(ap);
        if (qc) {
                qc->scsicmd = NULL;
                qc->ap = ap;
                qc->dev = dev;

                ata_qc_reinit(qc);
        }

        return qc;
}

/**
 *      ata_qc_free - free unused ata_queued_cmd
 *      @qc: Command to complete
 *
 *      Designed to free unused ata_queued_cmd object
 *      in case something prevents using it.
 *
 *      LOCKING:
 *      spin_lock_irqsave(host lock)
 */
void ata_qc_free(struct ata_queued_cmd *qc)
{
        struct ata_port *ap = qc->ap;
        unsigned int tag;

        WARN_ON(qc == NULL);    /* ata_qc_from_tag _might_ return NULL */

        qc->flags = 0;
        tag = qc->tag;
        if (likely(ata_tag_valid(tag))) {
                qc->tag = ATA_TAG_POISON;
                clear_bit(tag, &ap->qc_allocated);
        }
}

void __ata_qc_complete(struct ata_queued_cmd *qc)
{
        struct ata_port *ap = qc->ap;
        struct ata_link *link = qc->dev->link;

        WARN_ON(qc == NULL);    /* ata_qc_from_tag _might_ return NULL */
        WARN_ON(!(qc->flags & ATA_QCFLAG_ACTIVE));

        if (likely(qc->flags & ATA_QCFLAG_DMAMAP))
                ata_sg_clean(qc);

        /* command should be marked inactive atomically with qc completion */
        if (qc->tf.protocol == ATA_PROT_NCQ) {
                link->sactive &= ~(1 << qc->tag);
                if (!link->sactive)
                        ap->nr_active_links--;
        } else {
                link->active_tag = ATA_TAG_POISON;
                ap->nr_active_links--;
        }

        /* clear exclusive status */
        if (unlikely(qc->flags & ATA_QCFLAG_CLEAR_EXCL &&
                     ap->excl_link == link))
                ap->excl_link = NULL;

        /* atapi: mark qc as inactive to prevent the interrupt handler
         * from completing the command twice later, before the error handler
         * is called. (when rc != 0 and atapi request sense is needed)
         */
        qc->flags &= ~ATA_QCFLAG_ACTIVE;
        ap->qc_active &= ~(1 << qc->tag);

        /* call completion callback */
        qc->complete_fn(qc);
}

static void fill_result_tf(struct ata_queued_cmd *qc)
{
        struct ata_port *ap = qc->ap;

        qc->result_tf.flags = qc->tf.flags;
        ap->ops->qc_fill_rtf(qc);
}

static void ata_verify_xfer(struct ata_queued_cmd *qc)
{
        struct ata_device *dev = qc->dev;

        if (ata_tag_internal(qc->tag))
                return;

        if (ata_is_nodata(qc->tf.protocol))
                return;

        if ((dev->mwdma_mask || dev->udma_mask) && ata_is_pio(qc->tf.protocol))
                return;

        dev->flags &= ~ATA_DFLAG_DUBIOUS_XFER;
}

/**
 *      ata_qc_complete - Complete an active ATA command
 *      @qc: Command to complete
 *      @err_mask: ATA Status register contents
 *
 *      Indicate to the mid and upper layers that an ATA
 *      command has completed, with either an ok or not-ok status.
 *
 *      LOCKING:
 *      spin_lock_irqsave(host lock)
 */
void ata_qc_complete(struct ata_queued_cmd *qc)
{
        struct ata_port *ap = qc->ap;

        /* XXX: New EH and old EH use different mechanisms to
         * synchronize EH with regular execution path.
         *
         * In new EH, a failed qc is marked with ATA_QCFLAG_FAILED.
         * Normal execution path is responsible for not accessing a
         * failed qc.  libata core enforces the rule by returning NULL
         * from ata_qc_from_tag() for failed qcs.
         *
         * Old EH depends on ata_qc_complete() nullifying completion
         * requests if ATA_QCFLAG_EH_SCHEDULED is set.  Old EH does
         * not synchronize with interrupt handler.  Only PIO task is
         * taken care of.
         */
        if (ap->ops->error_handler) {
                struct ata_device *dev = qc->dev;
                struct ata_eh_info *ehi = &dev->link->eh_info;

                WARN_ON(ap->pflags & ATA_PFLAG_FROZEN);

                if (unlikely(qc->err_mask))
                        qc->flags |= ATA_QCFLAG_FAILED;

                if (unlikely(qc->flags & ATA_QCFLAG_FAILED)) {
                        if (!ata_tag_internal(qc->tag)) {
                                /* always fill result TF for failed qc */
                                fill_result_tf(qc);
                                ata_qc_schedule_eh(qc);
                                return;
                        }
                }

                /* read result TF if requested */
                if (qc->flags & ATA_QCFLAG_RESULT_TF)
                        fill_result_tf(qc);

                /* Some commands need post-processing after successful
                 * completion.
                 */
                switch (qc->tf.command) {
                case ATA_CMD_SET_FEATURES:
                        if (qc->tf.feature != SETFEATURES_WC_ON &&
                            qc->tf.feature != SETFEATURES_WC_OFF)
                                break;
                        /* fall through */
                case ATA_CMD_INIT_DEV_PARAMS: /* CHS translation changed */
                case ATA_CMD_SET_MULTI: /* multi_count changed */
                        /* revalidate device */
                        ehi->dev_action[dev->devno] |= ATA_EH_REVALIDATE;
                        ata_port_schedule_eh(ap);
                        break;

                case ATA_CMD_SLEEP:
                        dev->flags |= ATA_DFLAG_SLEEPING;
                        break;
                }

                if (unlikely(dev->flags & ATA_DFLAG_DUBIOUS_XFER))
                        ata_verify_xfer(qc);

                __ata_qc_complete(qc);
        } else {
                if (qc->flags & ATA_QCFLAG_EH_SCHEDULED)
                        return;

                /* read result TF if failed or requested */
                if (qc->err_mask || qc->flags & ATA_QCFLAG_RESULT_TF)
                        fill_result_tf(qc);

                __ata_qc_complete(qc);
        }
}

/**
 *      ata_qc_complete_multiple - Complete multiple qcs successfully
 *      @ap: port in question
 *      @qc_active: new qc_active mask
 *      @finish_qc: LLDD callback invoked before completing a qc
 *
 *      Complete in-flight commands.  This functions is meant to be
 *      called from low-level driver's interrupt routine to complete
 *      requests normally.  ap->qc_active and @qc_active is compared
 *      and commands are completed accordingly.
 *
 *      LOCKING:
 *      spin_lock_irqsave(host lock)
 *
 *      RETURNS:
 *      Number of completed commands on success, -errno otherwise.
 */
int ata_qc_complete_multiple(struct ata_port *ap, u32 qc_active,
                             void (*finish_qc)(struct ata_queued_cmd *))
{
        int nr_done = 0;
        u32 done_mask;
        int i;

        done_mask = ap->qc_active ^ qc_active;

        if (unlikely(done_mask & qc_active)) {
                ata_port_printk(ap, KERN_ERR, "illegal qc_active transition "
                                "(%08x->%08x)\n", ap->qc_active, qc_active);
                return -EINVAL;
        }

        for (i = 0; i < ATA_MAX_QUEUE; i++) {
                struct ata_queued_cmd *qc;

                if (!(done_mask & (1 << i)))
                        continue;

                if ((qc = ata_qc_from_tag(ap, i))) {
                        if (finish_qc)
                                finish_qc(qc);
                        ata_qc_complete(qc);
                        nr_done++;
                }
        }

        return nr_done;
}

/**
 *      ata_qc_issue - issue taskfile to device
 *      @qc: command to issue to device
 *
 *      Prepare an ATA command to submission to device.
 *      This includes mapping the data into a DMA-able
 *      area, filling in the S/G table, and finally
 *      writing the taskfile to hardware, starting the command.
 *
 *      LOCKING:
 *      spin_lock_irqsave(host lock)
 */
void ata_qc_issue(struct ata_queued_cmd *qc)
{
        struct ata_port *ap = qc->ap;
        struct ata_link *link = qc->dev->link;
        u8 prot = qc->tf.protocol;

        /* Make sure only one non-NCQ command is outstanding.  The
         * check is skipped for old EH because it reuses active qc to
         * request ATAPI sense.
         */
        WARN_ON(ap->ops->error_handler && ata_tag_valid(link->active_tag));

        if (ata_is_ncq(prot)) {
                WARN_ON(link->sactive & (1 << qc->tag));

                if (!link->sactive)
                        ap->nr_active_links++;
                link->sactive |= 1 << qc->tag;
        } else {
                WARN_ON(link->sactive);

                ap->nr_active_links++;
                link->active_tag = qc->tag;
        }

        qc->flags |= ATA_QCFLAG_ACTIVE;
        ap->qc_active |= 1 << qc->tag;

        /* We guarantee to LLDs that they will have at least one
         * non-zero sg if the command is a data command.
         */
        BUG_ON(ata_is_data(prot) && (!qc->sg || !qc->n_elem || !qc->nbytes));

        if (ata_is_dma(prot) || (ata_is_pio(prot) &&
                                 (ap->flags & ATA_FLAG_PIO_DMA)))
                if (ata_sg_setup(qc))
                        goto sg_err;

        /* if device is sleeping, schedule reset and abort the link */
        if (unlikely(qc->dev->flags & ATA_DFLAG_SLEEPING)) {
                link->eh_info.action |= ATA_EH_RESET;
                ata_ehi_push_desc(&link->eh_info, "waking up from sleep");
                ata_link_abort(link);
                return;
        }

        ap->ops->qc_prep(qc);

        qc->err_mask |= ap->ops->qc_issue(qc);
        if (unlikely(qc->err_mask))
                goto err;
        return;

sg_err:
        qc->err_mask |= AC_ERR_SYSTEM;
err:
        ata_qc_complete(qc);
}

/**
 *      sata_scr_valid - test whether SCRs are accessible
 *      @link: ATA link to test SCR accessibility for
 *
 *      Test whether SCRs are accessible for @link.
 *
 *      LOCKING:
 *      None.
 *
 *      RETURNS:
 *      1 if SCRs are accessible, 0 otherwise.
 */
int sata_scr_valid(struct ata_link *link)
{
        struct ata_port *ap = link->ap;

        return (ap->flags & ATA_FLAG_SATA) && ap->ops->scr_read;
}

/**
 *      sata_scr_read - read SCR register of the specified port
 *      @link: ATA link to read SCR for
 *      @reg: SCR to read
 *      @val: Place to store read value
 *
 *      Read SCR register @reg of @link into *@val.  This function is
 *      guaranteed to succeed if @link is ap->link, the cable type of
 *      the port is SATA and the port implements ->scr_read.
 *
 *      LOCKING:
 *      None if @link is ap->link.  Kernel thread context otherwise.
 *
 *      RETURNS:
 *      0 on success, negative errno on failure.
 */
int sata_scr_read(struct ata_link *link, int reg, u32 *val)
{
        if (ata_is_host_link(link)) {
                struct ata_port *ap = link->ap;

                if (sata_scr_valid(link))
                        return ap->ops->scr_read(ap, reg, val);
                return -EOPNOTSUPP;
        }

        return sata_pmp_scr_read(link, reg, val);
}

/**
 *      sata_scr_write - write SCR register of the specified port
 *      @link: ATA link to write SCR for
 *      @reg: SCR to write
 *      @val: value to write
 *
 *      Write @val to SCR register @reg of @link.  This function is
 *      guaranteed to succeed if @link is ap->link, the cable type of
 *      the port is SATA and the port implements ->scr_read.
 *
 *      LOCKING:
 *      None if @link is ap->link.  Kernel thread context otherwise.
 *
 *      RETURNS:
 *      0 on success, negative errno on failure.
 */
int sata_scr_write(struct ata_link *link, int reg, u32 val)
{
        if (ata_is_host_link(link)) {
                struct ata_port *ap = link->ap;

                if (sata_scr_valid(link))
                        return ap->ops->scr_write(ap, reg, val);
                return -EOPNOTSUPP;
        }

        return sata_pmp_scr_write(link, reg, val);
}

/**
 *      sata_scr_write_flush - write SCR register of the specified port and flush
 *      @link: ATA link to write SCR for
 *      @reg: SCR to write
 *      @val: value to write
 *
 *      This function is identical to sata_scr_write() except that this
 *      function performs flush after writing to the register.
 *
 *      LOCKING:
 *      None if @link is ap->link.  Kernel thread context otherwise.
 *
 *      RETURNS:
 *      0 on success, negative errno on failure.
 */
int sata_scr_write_flush(struct ata_link *link, int reg, u32 val)
{
        if (ata_is_host_link(link)) {
                struct ata_port *ap = link->ap;
                int rc;

                if (sata_scr_valid(link)) {
                        rc = ap->ops->scr_write(ap, reg, val);
                        if (rc == 0)
                                rc = ap->ops->scr_read(ap, reg, &val);
                        return rc;
                }
                return -EOPNOTSUPP;
        }

        return sata_pmp_scr_write(link, reg, val);
}

/**
 *      ata_link_online - test whether the given link is online
 *      @link: ATA link to test
 *
 *      Test whether @link is online.  Note that this function returns
 *      0 if online status of @link cannot be obtained, so
 *      ata_link_online(link) != !ata_link_offline(link).
 *
 *      LOCKING:
 *      None.
 *
 *      RETURNS:
 *      1 if the port online status is available and online.
 */
int ata_link_online(struct ata_link *link)
{
        u32 sstatus;

        if (sata_scr_read(link, SCR_STATUS, &sstatus) == 0 &&
            (sstatus & 0xf) == 0x3)
                return 1;
        return 0;
}

/**
 *      ata_link_offline - test whether the given link is offline
 *      @link: ATA link to test
 *
 *      Test whether @link is offline.  Note that this function
 *      returns 0 if offline status of @link cannot be obtained, so
 *      ata_link_online(link) != !ata_link_offline(link).
 *
 *      LOCKING:
 *      None.
 *
 *      RETURNS:
 *      1 if the port offline status is available and offline.
 */
int ata_link_offline(struct ata_link *link)
{
        u32 sstatus;

        if (sata_scr_read(link, SCR_STATUS, &sstatus) == 0 &&
            (sstatus & 0xf) != 0x3)
                return 1;
        return 0;
}

#ifdef CONFIG_PM
static int ata_host_request_pm(struct ata_host *host, pm_message_t mesg,
                               unsigned int action, unsigned int ehi_flags,
                               int wait)
{
        unsigned long flags;
        int i, rc;

        for (i = 0; i < host->n_ports; i++) {
                struct ata_port *ap = host->ports[i];
                struct ata_link *link;

                /* Previous resume operation might still be in
                 * progress.  Wait for PM_PENDING to clear.
                 */
                if (ap->pflags & ATA_PFLAG_PM_PENDING) {
                        ata_port_wait_eh(ap);
                        WARN_ON(ap->pflags & ATA_PFLAG_PM_PENDING);
                }

                /* request PM ops to EH */
                spin_lock_irqsave(ap->lock, flags);

                ap->pm_mesg = mesg;
                if (wait) {
                        rc = 0;
                        ap->pm_result = &rc;
                }

                ap->pflags |= ATA_PFLAG_PM_PENDING;
                __ata_port_for_each_link(link, ap) {
                        link->eh_info.action |= action;
                        link->eh_info.flags |= ehi_flags;
                }

                ata_port_schedule_eh(ap);

                spin_unlock_irqrestore(ap->lock, flags);

                /* wait and check result */
                if (wait) {
                        ata_port_wait_eh(ap);
                        WARN_ON(ap->pflags & ATA_PFLAG_PM_PENDING);
                        if (rc)
                                return rc;
                }
        }

        return 0;
}

/**
 *      ata_host_suspend - suspend host
 *      @host: host to suspend
 *      @mesg: PM message
 *
 *      Suspend @host.  Actual operation is performed by EH.  This
 *      function requests EH to perform PM operations and waits for EH
 *      to finish.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep).
 *
 *      RETURNS:
 *      0 on success, -errno on failure.
 */
int ata_host_suspend(struct ata_host *host, pm_message_t mesg)
{
        int rc;

        /*
         * disable link pm on all ports before requesting
         * any pm activity
         */
        ata_lpm_enable(host);

        rc = ata_host_request_pm(host, mesg, 0, ATA_EHI_QUIET, 1);
        if (rc == 0)
                host->dev->power.power_state = mesg;
        return rc;
}

/**
 *      ata_host_resume - resume host
 *      @host: host to resume
 *
 *      Resume @host.  Actual operation is performed by EH.  This
 *      function requests EH to perform PM operations and returns.
 *      Note that all resume operations are performed parallely.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep).
 */
void ata_host_resume(struct ata_host *host)
{
        ata_host_request_pm(host, PMSG_ON, ATA_EH_RESET,
                            ATA_EHI_NO_AUTOPSY | ATA_EHI_QUIET, 0);
        host->dev->power.power_state = PMSG_ON;

        /* reenable link pm */
        ata_lpm_disable(host);
}
#endif

/**
 *      ata_port_start - Set port up for dma.
 *      @ap: Port to initialize
 *
 *      Called just after data structures for each port are
 *      initialized.  Allocates space for PRD table.
 *
 *      May be used as the port_start() entry in ata_port_operations.
 *
 *      LOCKING:
 *      Inherited from caller.
 */
int ata_port_start(struct ata_port *ap)
{
        struct device *dev = ap->dev;

        ap->prd = dmam_alloc_coherent(dev, ATA_PRD_TBL_SZ, &ap->prd_dma,
                                      GFP_KERNEL);
        if (!ap->prd)
                return -ENOMEM;

        return 0;
}

/**
 *      ata_dev_init - Initialize an ata_device structure
 *      @dev: Device structure to initialize
 *
 *      Initialize @dev in preparation for probing.
 *
 *      LOCKING:
 *      Inherited from caller.
 */
void ata_dev_init(struct ata_device *dev)
{
        struct ata_link *link = dev->link;
        struct ata_port *ap = link->ap;
        unsigned long flags;

        /* SATA spd limit is bound to the first device */
        link->sata_spd_limit = link->hw_sata_spd_limit;
        link->sata_spd = 0;

        /* High bits of dev->flags are used to record warm plug
         * requests which occur asynchronously.  Synchronize using
         * host lock.
         */
        spin_lock_irqsave(ap->lock, flags);
        dev->flags &= ~ATA_DFLAG_INIT_MASK;
        dev->horkage = 0;
        spin_unlock_irqrestore(ap->lock, flags);

        memset((void *)dev + ATA_DEVICE_CLEAR_OFFSET, 0,
               sizeof(*dev) - ATA_DEVICE_CLEAR_OFFSET);
        dev->pio_mask = UINT_MAX;
        dev->mwdma_mask = UINT_MAX;
        dev->udma_mask = UINT_MAX;
}

/**
 *      ata_link_init - Initialize an ata_link structure
 *      @ap: ATA port link is attached to
 *      @link: Link structure to initialize
 *      @pmp: Port multiplier port number
 *
 *      Initialize @link.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep)
 */
void ata_link_init(struct ata_port *ap, struct ata_link *link, int pmp)
{
        int i;

        /* clear everything except for devices */
        memset(link, 0, offsetof(struct ata_link, device[0]));

        link->ap = ap;
        link->pmp = pmp;
        link->active_tag = ATA_TAG_POISON;
        link->hw_sata_spd_limit = UINT_MAX;

        /* can't use iterator, ap isn't initialized yet */
        for (i = 0; i < ATA_MAX_DEVICES; i++) {
                struct ata_device *dev = &link->device[i];

                dev->link = link;
                dev->devno = dev - link->device;
                ata_dev_init(dev);
        }
}

/**
 *      sata_link_init_spd - Initialize link->sata_spd_limit
 *      @link: Link to configure sata_spd_limit for
 *
 *      Initialize @link->[hw_]sata_spd_limit to the currently
 *      configured value.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep).
 *
 *      RETURNS:
 *      0 on success, -errno on failure.
 */
int sata_link_init_spd(struct ata_link *link)
{
        u32 scontrol;
        u8 spd;
        int rc;

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

        spd = (scontrol >> 4) & 0xf;
        if (spd)
                link->hw_sata_spd_limit &= (1 << spd) - 1;

        ata_force_spd_limit(link);

        link->sata_spd_limit = link->hw_sata_spd_limit;

        return 0;
}

/**
 *      ata_port_alloc - allocate and initialize basic ATA port resources
 *      @host: ATA host this allocated port belongs to
 *
 *      Allocate and initialize basic ATA port resources.
 *
 *      RETURNS:
 *      Allocate ATA port on success, NULL on failure.
 *
 *      LOCKING:
 *      Inherited from calling layer (may sleep).
 */
struct ata_port *ata_port_alloc(struct ata_host *host)
{
        struct ata_port *ap;

        DPRINTK("ENTER\n");

        ap = kzalloc(sizeof(*ap), GFP_KERNEL);
        if (!ap)
                return NULL;

        ap->pflags |= ATA_PFLAG_INITIALIZING;
        ap->lock = &host->lock;
        ap->flags = ATA_FLAG_DISABLED;
        ap->print_id = -1;
        ap->ctl = ATA_DEVCTL_OBS;
        ap->host = host;
        ap->dev = host->dev;
        ap->last_ctl = 0xFF;

#if defined(ATA_VERBOSE_DEBUG)
        /* turn on all debugging levels */
        ap->msg_enable = 0x00FF;
#elif defined(ATA_DEBUG)
        ap->msg_enable = ATA_MSG_DRV | ATA_MSG_INFO | ATA_MSG_CTL | ATA_MSG_WARN | ATA_MSG_ERR;
#else
        ap->msg_enable = ATA_MSG_DRV | ATA_MSG_ERR | ATA_MSG_WARN;
#endif

        INIT_DELAYED_WORK(&ap->port_task, ata_pio_task);
        INIT_DELAYED_WORK(&ap->hotplug_task, ata_scsi_hotplug);
        INIT_WORK(&ap->scsi_rescan_task, ata_scsi_dev_rescan);
        INIT_LIST_HEAD(&ap->eh_done_q);
        init_waitqueue_head(&ap->eh_wait_q);
        init_timer_deferrable(&ap->fastdrain_timer);
        ap->fastdrain_timer.function = ata_eh_fastdrain_timerfn;
        ap->fastdrain_timer.data = (unsigned long)ap;

        ap->cbl = ATA_CBL_NONE;

        ata_link_init(ap, &ap->link, 0);

#ifdef ATA_IRQ_TRAP
        ap->stats.unhandled_irq = 1;
        ap->stats.idle_irq = 1;
#endif
        return ap;
}

static void ata_host_release(struct device *gendev, void *res)
{
        struct ata_host *host = dev_get_drvdata(gendev);
        int i;

        for (i = 0; i < host->n_ports; i++) {
                struct ata_port *ap = host->ports[i];

                if (!ap)
                        continue;

                if (ap->scsi_host)
                        scsi_host_put(ap->scsi_host);

                kfree(ap->pmp_link);
                kfree(ap);
                host->ports[i] = NULL;
        }

        dev_set_drvdata(gendev, NULL);
}

/**
 *      ata_host_alloc - allocate and init basic ATA host resources
 *      @dev: generic device this host is associated with
 *      @max_ports: maximum number of ATA ports associated with this host
 *
 *      Allocate and initialize basic ATA host resources.  LLD calls
 *      this function to allocate a host, initializes it fully and
 *      attaches it using ata_host_register().
 *
 *      @max_ports ports are allocated and host->n_ports is
 *      initialized to @max_ports.  The caller is allowed to decrease
 *      host->n_ports before calling ata_host_register().  The unused
 *      ports will be automatically freed on registration.
 *
 *      RETURNS:
 *      Allocate ATA host on success, NULL on failure.
 *
 *      LOCKING:
 *      Inherited from calling layer (may sleep).
 */
struct ata_host *ata_host_alloc(struct device *dev, int max_ports)
{
        struct ata_host *host;
        size_t sz;
        int i;

        DPRINTK("ENTER\n");

        if (!devres_open_group(dev, NULL, GFP_KERNEL))
                return NULL;

        /* alloc a container for our list of ATA ports (buses) */
        sz = sizeof(struct ata_host) + (max_ports + 1) * sizeof(void *);
        /* alloc a container for our list of ATA ports (buses) */
        host = devres_alloc(ata_host_release, sz, GFP_KERNEL);
        if (!host)
                goto err_out;

        devres_add(dev, host);
        dev_set_drvdata(dev, host);

        spin_lock_init(&host->lock);
        host->dev = dev;
        host->n_ports = max_ports;

        /* allocate ports bound to this host */
        for (i = 0; i < max_ports; i++) {
                struct ata_port *ap;

                ap = ata_port_alloc(host);
                if (!ap)
                        goto err_out;

                ap->port_no = i;
                host->ports[i] = ap;
        }

        devres_remove_group(dev, NULL);
        return host;

 err_out:
        devres_release_group(dev, NULL);
        return NULL;
}

/**
 *      ata_host_alloc_pinfo - alloc host and init with port_info array
 *      @dev: generic device this host is associated with
 *      @ppi: array of ATA port_info to initialize host with
 *      @n_ports: number of ATA ports attached to this host
 *
 *      Allocate ATA host and initialize with info from @ppi.  If NULL
 *      terminated, @ppi may contain fewer entries than @n_ports.  The
 *      last entry will be used for the remaining ports.
 *
 *      RETURNS:
 *      Allocate ATA host on success, NULL on failure.
 *
 *      LOCKING:
 *      Inherited from calling layer (may sleep).
 */
struct ata_host *ata_host_alloc_pinfo(struct device *dev,
                                      const struct ata_port_info * const * ppi,
                                      int n_ports)
{
        const struct ata_port_info *pi;
        struct ata_host *host;
        int i, j;

        host = ata_host_alloc(dev, n_ports);
        if (!host)
                return NULL;

        for (i = 0, j = 0, pi = NULL; i < host->n_ports; i++) {
                struct ata_port *ap = host->ports[i];

                if (ppi[j])
                        pi = ppi[j++];

                ap->pio_mask = pi->pio_mask;
                ap->mwdma_mask = pi->mwdma_mask;
                ap->udma_mask = pi->udma_mask;
                ap->flags |= pi->flags;
                ap->link.flags |= pi->link_flags;
                ap->ops = pi->port_ops;

                if (!host->ops && (pi->port_ops != &ata_dummy_port_ops))
                        host->ops = pi->port_ops;
        }

        return host;
}

static void ata_host_stop(struct device *gendev, void *res)
{
        struct ata_host *host = dev_get_drvdata(gendev);
        int i;

        WARN_ON(!(host->flags & ATA_HOST_STARTED));

        for (i = 0; i < host->n_ports; i++) {
                struct ata_port *ap = host->ports[i];

                if (ap->ops->port_stop)
                        ap->ops->port_stop(ap);
        }

        if (host->ops->host_stop)
                host->ops->host_stop(host);
}

/**
 *      ata_finalize_port_ops - finalize ata_port_operations
 *      @ops: ata_port_operations to finalize
 *
 *      An ata_port_operations can inherit from another ops and that
 *      ops can again inherit from another.  This can go on as many
 *      times as necessary as long as there is no loop in the
 *      inheritance chain.
 *
 *      Ops tables are finalized when the host is started.  NULL or
 *      unspecified entries are inherited from the closet ancestor
 *      which has the method and the entry is populated with it.
 *      After finalization, the ops table directly points to all the
 *      methods and ->inherits is no longer necessary and cleared.
 *
 *      Using ATA_OP_NULL, inheriting ops can force a method to NULL.
 *
 *      LOCKING:
 *      None.
 */
static void ata_finalize_port_ops(struct ata_port_operations *ops)
{
        static spinlock_t lock = SPIN_LOCK_UNLOCKED;
        const struct ata_port_operations *cur;
        void **begin = (void **)ops;
        void **end = (void **)&ops->inherits;
        void **pp;

        if (!ops || !ops->inherits)
                return;

        spin_lock(&lock);

        for (cur = ops->inherits; cur; cur = cur->inherits) {
                void **inherit = (void **)cur;

                for (pp = begin; pp < end; pp++, inherit++)
                        if (!*pp)
                                *pp = *inherit;
        }

        for (pp = begin; pp < end; pp++)
                if (IS_ERR(*pp))
                        *pp = NULL;

        ops->inherits = NULL;

        spin_unlock(&lock);
}

/**
 *      ata_host_start - start and freeze ports of an ATA host
 *      @host: ATA host to start ports for
 *
 *      Start and then freeze ports of @host.  Started status is
 *      recorded in host->flags, so this function can be called
 *      multiple times.  Ports are guaranteed to get started only
 *      once.  If host->ops isn't initialized yet, its set to the
 *      first non-dummy port ops.
 *
 *      LOCKING:
 *      Inherited from calling layer (may sleep).
 *
 *      RETURNS:
 *      0 if all ports are started successfully, -errno otherwise.
 */
int ata_host_start(struct ata_host *host)
{
        int have_stop = 0;
        void *start_dr = NULL;
        int i, rc;

        if (host->flags & ATA_HOST_STARTED)
                return 0;

        ata_finalize_port_ops(host->ops);

        for (i = 0; i < host->n_ports; i++) {
                struct ata_port *ap = host->ports[i];

                ata_finalize_port_ops(ap->ops);

                if (!host->ops && !ata_port_is_dummy(ap))
                        host->ops = ap->ops;

                if (ap->ops->port_stop)
                        have_stop = 1;
        }

        if (host->ops->host_stop)
                have_stop = 1;

        if (have_stop) {
                start_dr = devres_alloc(ata_host_stop, 0, GFP_KERNEL);
                if (!start_dr)
                        return -ENOMEM;
        }

        for (i = 0; i < host->n_ports; i++) {
                struct ata_port *ap = host->ports[i];

                if (ap->ops->port_start) {
                        rc = ap->ops->port_start(ap);
                        if (rc) {
                                if (rc != -ENODEV)
                                        dev_printk(KERN_ERR, host->dev,
                                                "failed to start port %d "
                                                "(errno=%d)\n", i, rc);
                                goto err_out;
                        }
                }
                ata_eh_freeze_port(ap);
        }

        if (start_dr)
                devres_add(host->dev, start_dr);
        host->flags |= ATA_HOST_STARTED;
        return 0;

 err_out:
        while (--i >= 0) {
                struct ata_port *ap = host->ports[i];

                if (ap->ops->port_stop)
                        ap->ops->port_stop(ap);
        }
        devres_free(start_dr);
        return rc;
}

/**
 *      ata_sas_host_init - Initialize a host struct
 *      @host:  host to initialize
 *      @dev:   device host is attached to
 *      @flags: host flags
 *      @ops:   port_ops
 *
 *      LOCKING:
 *      PCI/etc. bus probe sem.
 *
 */
/* KILLME - the only user left is ipr */
void ata_host_init(struct ata_host *host, struct device *dev,
                   unsigned long flags, struct ata_port_operations *ops)
{
        spin_lock_init(&host->lock);
        host->dev = dev;
        host->flags = flags;
        host->ops = ops;
}

/**
 *      ata_host_register - register initialized ATA host
 *      @host: ATA host to register
 *      @sht: template for SCSI host
 *
 *      Register initialized ATA host.  @host is allocated using
 *      ata_host_alloc() and fully initialized by LLD.  This function
 *      starts ports, registers @host with ATA and SCSI layers and
 *      probe registered devices.
 *
 *      LOCKING:
 *      Inherited from calling layer (may sleep).
 *
 *      RETURNS:
 *      0 on success, -errno otherwise.
 */
int ata_host_register(struct ata_host *host, struct scsi_host_template *sht)
{
        int i, rc;

        /* host must have been started */
        if (!(host->flags & ATA_HOST_STARTED)) {
                dev_printk(KERN_ERR, host->dev,
                           "BUG: trying to register unstarted host\n");
                WARN_ON(1);
                return -EINVAL;
        }

        /* Blow away unused ports.  This happens when LLD can't
         * determine the exact number of ports to allocate at
         * allocation time.
         */
        for (i = host->n_ports; host->ports[i]; i++)
                kfree(host->ports[i]);

        /* give ports names and add SCSI hosts */
        for (i = 0; i < host->n_ports; i++)
                host->ports[i]->print_id = ata_print_id++;

        rc = ata_scsi_add_hosts(host, sht);
        if (rc)
                return rc;

        /* associate with ACPI nodes */
        ata_acpi_associate(host);

        /* set cable, sata_spd_limit and report */
        for (i = 0; i < host->n_ports; i++) {
                struct ata_port *ap = host->ports[i];
                unsigned long xfer_mask;

                /* set SATA cable type if still unset */
                if (ap->cbl == ATA_CBL_NONE && (ap->flags & ATA_FLAG_SATA))
                        ap->cbl = ATA_CBL_SATA;

                /* init sata_spd_limit to the current value */
                sata_link_init_spd(&ap->link);

                /* print per-port info to dmesg */
                xfer_mask = ata_pack_xfermask(ap->pio_mask, ap->mwdma_mask,
                                              ap->udma_mask);

                if (!ata_port_is_dummy(ap)) {
                        ata_port_printk(ap, KERN_INFO,
                                        "%cATA max %s %s\n",
                                        (ap->flags & ATA_FLAG_SATA) ? 'S' : 'P',
                                        ata_mode_string(xfer_mask),
                                        ap->link.eh_info.desc);
                        ata_ehi_clear_desc(&ap->link.eh_info);
                } else
                        ata_port_printk(ap, KERN_INFO, "DUMMY\n");
        }

        /* perform each probe synchronously */
        DPRINTK("probe begin\n");
        for (i = 0; i < host->n_ports; i++) {
                struct ata_port *ap = host->ports[i];

                /* probe */
                if (ap->ops->error_handler) {
                        struct ata_eh_info *ehi = &ap->link.eh_info;
                        unsigned long flags;

                        ata_port_probe(ap);

                        /* kick EH for boot probing */
                        spin_lock_irqsave(ap->lock, flags);

                        ehi->probe_mask |= ATA_ALL_DEVICES;
                        ehi->action |= ATA_EH_RESET;
                        ehi->flags |= ATA_EHI_NO_AUTOPSY | ATA_EHI_QUIET;

                        ap->pflags &= ~ATA_PFLAG_INITIALIZING;
                        ap->pflags |= ATA_PFLAG_LOADING;
                        ata_port_schedule_eh(ap);

                        spin_unlock_irqrestore(ap->lock, flags);

                        /* wait for EH to finish */
                        ata_port_wait_eh(ap);
                } else {
                        DPRINTK("ata%u: bus probe begin\n", ap->print_id);
                        rc = ata_bus_probe(ap);
                        DPRINTK("ata%u: bus probe end\n", ap->print_id);

                        if (rc) {
                                /* FIXME: do something useful here?
                                 * Current libata behavior will
                                 * tear down everything when
                                 * the module is removed
                                 * or the h/w is unplugged.
                                 */
                        }
                }
        }

        /* probes are done, now scan each port's disk(s) */
        DPRINTK("host probe begin\n");
        for (i = 0; i < host->n_ports; i++) {
                struct ata_port *ap = host->ports[i];

                ata_scsi_scan_host(ap, 1);
                ata_lpm_schedule(ap, ap->pm_policy);
        }

        return 0;
}

/**
 *      ata_host_activate - start host, request IRQ and register it
 *      @host: target ATA host
 *      @irq: IRQ to request
 *      @irq_handler: irq_handler used when requesting IRQ
 *      @irq_flags: irq_flags used when requesting IRQ
 *      @sht: scsi_host_template to use when registering the host
 *
 *      After allocating an ATA host and initializing it, most libata
 *      LLDs perform three steps to activate the host - start host,
 *      request IRQ and register it.  This helper takes necessasry
 *      arguments and performs the three steps in one go.
 *
 *      An invalid IRQ skips the IRQ registration and expects the host to
 *      have set polling mode on the port. In this case, @irq_handler
 *      should be NULL.
 *
 *      LOCKING:
 *      Inherited from calling layer (may sleep).
 *
 *      RETURNS:
 *      0 on success, -errno otherwise.
 */
int ata_host_activate(struct ata_host *host, int irq,
                      irq_handler_t irq_handler, unsigned long irq_flags,
                      struct scsi_host_template *sht)
{
        int i, rc;

        rc = ata_host_start(host);
        if (rc)
                return rc;

        /* Special case for polling mode */
        if (!irq) {
                WARN_ON(irq_handler);
                return ata_host_register(host, sht);
        }

        rc = devm_request_irq(host->dev, irq, irq_handler, irq_flags,
                              dev_driver_string(host->dev), host);
        if (rc)
                return rc;

        for (i = 0; i < host->n_ports; i++)
                ata_port_desc(host->ports[i], "irq %d", irq);

        rc = ata_host_register(host, sht);
        /* if failed, just free the IRQ and leave ports alone */
        if (rc)
                devm_free_irq(host->dev, irq, host);

        return rc;
}

/**
 *      ata_port_detach - Detach ATA port in prepration of device removal
 *      @ap: ATA port to be detached
 *
 *      Detach all ATA devices and the associated SCSI devices of @ap;
 *      then, remove the associated SCSI host.  @ap is guaranteed to
 *      be quiescent on return from this function.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep).
 */
static void ata_port_detach(struct ata_port *ap)
{
        unsigned long flags;
        struct ata_link *link;
        struct ata_device *dev;

        if (!ap->ops->error_handler)
                goto skip_eh;

        /* tell EH we're leaving & flush EH */
        spin_lock_irqsave(ap->lock, flags);
        ap->pflags |= ATA_PFLAG_UNLOADING;
        spin_unlock_irqrestore(ap->lock, flags);

        ata_port_wait_eh(ap);

        /* EH is now guaranteed to see UNLOADING - EH context belongs
         * to us.  Disable all existing devices.
         */
        ata_port_for_each_link(link, ap) {
                ata_link_for_each_dev(dev, link)
                        ata_dev_disable(dev);
        }

        /* Final freeze & EH.  All in-flight commands are aborted.  EH
         * will be skipped and retrials will be terminated with bad
         * target.
         */
        spin_lock_irqsave(ap->lock, flags);
        ata_port_freeze(ap);    /* won't be thawed */
        spin_unlock_irqrestore(ap->lock, flags);

        ata_port_wait_eh(ap);
        cancel_rearming_delayed_work(&ap->hotplug_task);

 skip_eh:
        /* remove the associated SCSI host */
        scsi_remove_host(ap->scsi_host);
}

/**
 *      ata_host_detach - Detach all ports of an ATA host
 *      @host: Host to detach
 *
 *      Detach all ports of @host.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep).
 */
void ata_host_detach(struct ata_host *host)
{
        int i;

        for (i = 0; i < host->n_ports; i++)
                ata_port_detach(host->ports[i]);

        /* the host is dead now, dissociate ACPI */
        ata_acpi_dissociate(host);
}

#ifdef CONFIG_PCI

/**
 *      ata_pci_remove_one - PCI layer callback for device removal
 *      @pdev: PCI device that was removed
 *
 *      PCI layer indicates to libata via this hook that hot-unplug or
 *      module unload event has occurred.  Detach all ports.  Resource
 *      release is handled via devres.
 *
 *      LOCKING:
 *      Inherited from PCI layer (may sleep).
 */
void ata_pci_remove_one(struct pci_dev *pdev)
{
        struct device *dev = &pdev->dev;
        struct ata_host *host = dev_get_drvdata(dev);

        ata_host_detach(host);
}

/* move to PCI subsystem */
int pci_test_config_bits(struct pci_dev *pdev, const struct pci_bits *bits)
{
        unsigned long tmp = 0;

        switch (bits->width) {
        case 1: {
                u8 tmp8 = 0;
                pci_read_config_byte(pdev, bits->reg, &tmp8);
                tmp = tmp8;
                break;
        }
        case 2: {
                u16 tmp16 = 0;
                pci_read_config_word(pdev, bits->reg, &tmp16);
                tmp = tmp16;
                break;
        }
        case 4: {
                u32 tmp32 = 0;
                pci_read_config_dword(pdev, bits->reg, &tmp32);
                tmp = tmp32;
                break;
        }

        default:
                return -EINVAL;
        }

        tmp &= bits->mask;

        return (tmp == bits->val) ? 1 : 0;
}

#ifdef CONFIG_PM
void ata_pci_device_do_suspend(struct pci_dev *pdev, pm_message_t mesg)
{
        pci_save_state(pdev);
        pci_disable_device(pdev);

        if (mesg.event & PM_EVENT_SLEEP)
                pci_set_power_state(pdev, PCI_D3hot);
}

int ata_pci_device_do_resume(struct pci_dev *pdev)
{
        int rc;

        pci_set_power_state(pdev, PCI_D0);
        pci_restore_state(pdev);

        rc = pcim_enable_device(pdev);
        if (rc) {
                dev_printk(KERN_ERR, &pdev->dev,
                           "failed to enable device after resume (%d)\n", rc);
                return rc;
        }

        pci_set_master(pdev);
        return 0;
}

int ata_pci_device_suspend(struct pci_dev *pdev, pm_message_t mesg)
{
        struct ata_host *host = dev_get_drvdata(&pdev->dev);
        int rc = 0;

        rc = ata_host_suspend(host, mesg);
        if (rc)
                return rc;

        ata_pci_device_do_suspend(pdev, mesg);

        return 0;
}

int ata_pci_device_resume(struct pci_dev *pdev)
{
        struct ata_host *host = dev_get_drvdata(&pdev->dev);
        int rc;

        rc = ata_pci_device_do_resume(pdev);
        if (rc == 0)
                ata_host_resume(host);
        return rc;
}
#endif /* CONFIG_PM */

#endif /* CONFIG_PCI */

static int __init ata_parse_force_one(char **cur,
                                      struct ata_force_ent *force_ent,
                                      const char **reason)
{
        /* FIXME: Currently, there's no way to tag init const data and
         * using __initdata causes build failure on some versions of
         * gcc.  Once __initdataconst is implemented, add const to the
         * following structure.
         */
        static struct ata_force_param force_tbl[] __initdata = {
                { "40c",        .cbl            = ATA_CBL_PATA40 },
                { "80c",        .cbl            = ATA_CBL_PATA80 },
                { "short40c",   .cbl            = ATA_CBL_PATA40_SHORT },
                { "unk",        .cbl            = ATA_CBL_PATA_UNK },
                { "ign",        .cbl            = ATA_CBL_PATA_IGN },
                { "sata",       .cbl            = ATA_CBL_SATA },
                { "1.5Gbps",    .spd_limit      = 1 },
                { "3.0Gbps",    .spd_limit      = 2 },
                { "noncq",      .horkage_on     = ATA_HORKAGE_NONCQ },
                { "ncq",        .horkage_off    = ATA_HORKAGE_NONCQ },
                { "pio0",       .xfer_mask      = 1 << (ATA_SHIFT_PIO + 0) },
                { "pio1",       .xfer_mask      = 1 << (ATA_SHIFT_PIO + 1) },
                { "pio2",       .xfer_mask      = 1 << (ATA_SHIFT_PIO + 2) },
                { "pio3",       .xfer_mask      = 1 << (ATA_SHIFT_PIO + 3) },
                { "pio4",       .xfer_mask      = 1 << (ATA_SHIFT_PIO + 4) },
                { "pio5",       .xfer_mask      = 1 << (ATA_SHIFT_PIO + 5) },
                { "pio6",       .xfer_mask      = 1 << (ATA_SHIFT_PIO + 6) },
                { "mwdma0",     .xfer_mask      = 1 << (ATA_SHIFT_MWDMA + 0) },
                { "mwdma1",     .xfer_mask      = 1 << (ATA_SHIFT_MWDMA + 1) },
                { "mwdma2",     .xfer_mask      = 1 << (ATA_SHIFT_MWDMA + 2) },
                { "mwdma3",     .xfer_mask      = 1 << (ATA_SHIFT_MWDMA + 3) },
                { "mwdma4",     .xfer_mask      = 1 << (ATA_SHIFT_MWDMA + 4) },
                { "udma0",      .xfer_mask      = 1 << (ATA_SHIFT_UDMA + 0) },
                { "udma16",     .xfer_mask      = 1 << (ATA_SHIFT_UDMA + 0) },
                { "udma/16",    .xfer_mask      = 1 << (ATA_SHIFT_UDMA + 0) },
                { "udma1",      .xfer_mask      = 1 << (ATA_SHIFT_UDMA + 1) },
                { "udma25",     .xfer_mask      = 1 << (ATA_SHIFT_UDMA + 1) },
                { "udma/25",    .xfer_mask      = 1 << (ATA_SHIFT_UDMA + 1) },
                { "udma2",      .xfer_mask      = 1 << (ATA_SHIFT_UDMA + 2) },
                { "udma33",     .xfer_mask      = 1 << (ATA_SHIFT_UDMA + 2) },
                { "udma/33",    .xfer_mask      = 1 << (ATA_SHIFT_UDMA + 2) },
                { "udma3",      .xfer_mask      = 1 << (ATA_SHIFT_UDMA + 3) },
                { "udma44",     .xfer_mask      = 1 << (ATA_SHIFT_UDMA + 3) },
                { "udma/44",    .xfer_mask      = 1 << (ATA_SHIFT_UDMA + 3) },
                { "udma4",      .xfer_mask      = 1 << (ATA_SHIFT_UDMA + 4) },
                { "udma66",     .xfer_mask      = 1 << (ATA_SHIFT_UDMA + 4) },
                { "udma/66",    .xfer_mask      = 1 << (ATA_SHIFT_UDMA + 4) },
                { "udma5",      .xfer_mask      = 1 << (ATA_SHIFT_UDMA + 5) },
                { "udma100",    .xfer_mask      = 1 << (ATA_SHIFT_UDMA + 5) },
                { "udma/100",   .xfer_mask      = 1 << (ATA_SHIFT_UDMA + 5) },
                { "udma6",      .xfer_mask      = 1 << (ATA_SHIFT_UDMA + 6) },
                { "udma133",    .xfer_mask      = 1 << (ATA_SHIFT_UDMA + 6) },
                { "udma/133",   .xfer_mask      = 1 << (ATA_SHIFT_UDMA + 6) },
                { "udma7",      .xfer_mask      = 1 << (ATA_SHIFT_UDMA + 7) },
        };
        char *start = *cur, *p = *cur;
        char *id, *val, *endp;
        const struct ata_force_param *match_fp = NULL;
        int nr_matches = 0, i;

        /* find where this param ends and update *cur */
        while (*p != '\0' && *p != ',')
                p++;

        if (*p == '\0')
                *cur = p;
        else
                *cur = p + 1;

        *p = '\0';

        /* parse */
        p = strchr(start, ':');
        if (!p) {
                val = strstrip(start);
                goto parse_val;
        }
        *p = '\0';

        id = strstrip(start);
        val = strstrip(p + 1);

        /* parse id */
        p = strchr(id, '.');
        if (p) {
                *p++ = '\0';
                force_ent->device = simple_strtoul(p, &endp, 10);
                if (p == endp || *endp != '\0') {
                        *reason = "invalid device";
                        return -EINVAL;
                }
        }

        force_ent->port = simple_strtoul(id, &endp, 10);
        if (p == endp || *endp != '\0') {
                *reason = "invalid port/link";
                return -EINVAL;
        }

 parse_val:
        /* parse val, allow shortcuts so that both 1.5 and 1.5Gbps work */
        for (i = 0; i < ARRAY_SIZE(force_tbl); i++) {
                const struct ata_force_param *fp = &force_tbl[i];

                if (strncasecmp(val, fp->name, strlen(val)))
                        continue;

                nr_matches++;
                match_fp = fp;

                if (strcasecmp(val, fp->name) == 0) {
                        nr_matches = 1;
                        break;
                }
        }

        if (!nr_matches) {
                *reason = "unknown value";
                return -EINVAL;
        }
        if (nr_matches > 1) {
                *reason = "ambigious value";
                return -EINVAL;
        }

        force_ent->param = *match_fp;

        return 0;
}

static void __init ata_parse_force_param(void)
{
        int idx = 0, size = 1;
        int last_port = -1, last_device = -1;
        char *p, *cur, *next;

        /* calculate maximum number of params and allocate force_tbl */
        for (p = ata_force_param_buf; *p; p++)
                if (*p == ',')
                        size++;

        ata_force_tbl = kzalloc(sizeof(ata_force_tbl[0]) * size, GFP_KERNEL);
        if (!ata_force_tbl) {
                printk(KERN_WARNING "ata: failed to extend force table, "
                       "libata.force ignored\n");
                return;
        }

        /* parse and populate the table */
        for (cur = ata_force_param_buf; *cur != '\0'; cur = next) {
                const char *reason = "";
                struct ata_force_ent te = { .port = -1, .device = -1 };

                next = cur;
                if (ata_parse_force_one(&next, &te, &reason)) {
                        printk(KERN_WARNING "ata: failed to parse force "
                               "parameter \"%s\" (%s)\n",
                               cur, reason);
                        continue;
                }

                if (te.port == -1) {
                        te.port = last_port;
                        te.device = last_device;
                }

                ata_force_tbl[idx++] = te;

                last_port = te.port;
                last_device = te.device;
        }

        ata_force_tbl_size = idx;
}

static int __init ata_init(void)
{
        ata_probe_timeout *= HZ;

        ata_parse_force_param();

        ata_wq = create_workqueue("ata");
        if (!ata_wq)
                return -ENOMEM;

        ata_aux_wq = create_singlethread_workqueue("ata_aux");
        if (!ata_aux_wq) {
                destroy_workqueue(ata_wq);
                return -ENOMEM;
        }

        printk(KERN_DEBUG "libata version " DRV_VERSION " loaded.\n");
        return 0;
}

static void __exit ata_exit(void)
{
        kfree(ata_force_tbl);
        destroy_workqueue(ata_wq);
        destroy_workqueue(ata_aux_wq);
}

subsys_initcall(ata_init);
module_exit(ata_exit);

static unsigned long ratelimit_time;
static DEFINE_SPINLOCK(ata_ratelimit_lock);

int ata_ratelimit(void)
{
        int rc;
        unsigned long flags;

        spin_lock_irqsave(&ata_ratelimit_lock, flags);

        if (time_after(jiffies, ratelimit_time)) {
                rc = 1;
                ratelimit_time = jiffies + (HZ/5);
        } else
                rc = 0;

        spin_unlock_irqrestore(&ata_ratelimit_lock, flags);

        return rc;
}

/**
 *      ata_wait_register - wait until register value changes
 *      @reg: IO-mapped register
 *      @mask: Mask to apply to read register value
 *      @val: Wait condition
 *      @interval_msec: polling interval in milliseconds
 *      @timeout_msec: timeout in milliseconds
 *
 *      Waiting for some bits of register to change is a common
 *      operation for ATA controllers.  This function reads 32bit LE
 *      IO-mapped register @reg and tests for the following condition.
 *
 *      (*@reg & mask) != val
 *
 *      If the condition is met, it returns; otherwise, the process is
 *      repeated after @interval_msec until timeout.
 *
 *      LOCKING:
 *      Kernel thread context (may sleep)
 *
 *      RETURNS:
 *      The final register value.
 */
u32 ata_wait_register(void __iomem *reg, u32 mask, u32 val,
                      unsigned long interval_msec,
                      unsigned long timeout_msec)
{
        unsigned long timeout;
        u32 tmp;

        tmp = ioread32(reg);

        /* Calculate timeout _after_ the first read to make sure
         * preceding writes reach the controller before starting to
         * eat away the timeout.
         */
        timeout = jiffies + (timeout_msec * HZ) / 1000;

        while ((tmp & mask) == val && time_before(jiffies, timeout)) {
                msleep(interval_msec);
                tmp = ioread32(reg);
        }

        return tmp;
}

/*
 * Dummy port_ops
 */
static void ata_dummy_noret(struct ata_port *ap)        { }
static int ata_dummy_ret0(struct ata_port *ap)          { return 0; }
static void ata_dummy_qc_noret(struct ata_queued_cmd *qc) { }

static u8 ata_dummy_check_status(struct ata_port *ap)
{
        return ATA_DRDY;
}

static unsigned int ata_dummy_qc_issue(struct ata_queued_cmd *qc)
{
        return AC_ERR_SYSTEM;
}

struct ata_port_operations ata_dummy_port_ops = {
        .sff_check_status       = ata_dummy_check_status,
        .sff_check_altstatus    = ata_dummy_check_status,
        .sff_dev_select         = ata_noop_dev_select,
        .qc_prep                = ata_noop_qc_prep,
        .qc_issue               = ata_dummy_qc_issue,
        .freeze                 = ata_dummy_noret,
        .thaw                   = ata_dummy_noret,
        .error_handler          = ata_dummy_noret,
        .post_internal_cmd      = ata_dummy_qc_noret,
        .sff_irq_clear          = ata_dummy_noret,
        .port_start             = ata_dummy_ret0,
        .port_stop              = ata_dummy_noret,
};

const struct ata_port_info ata_dummy_port_info = {
        .port_ops               = &ata_dummy_port_ops,
};

/*
 * libata is essentially a library of internal helper functions for
 * low-level ATA host controller drivers.  As such, the API/ABI is
 * likely to change as new drivers are added and updated.
 * Do not depend on ABI/API stability.
 */
EXPORT_SYMBOL_GPL(sata_deb_timing_normal);
EXPORT_SYMBOL_GPL(sata_deb_timing_hotplug);
EXPORT_SYMBOL_GPL(sata_deb_timing_long);
EXPORT_SYMBOL_GPL(ata_base_port_ops);
EXPORT_SYMBOL_GPL(sata_port_ops);
EXPORT_SYMBOL_GPL(sata_pmp_port_ops);
EXPORT_SYMBOL_GPL(ata_dummy_port_ops);
EXPORT_SYMBOL_GPL(ata_dummy_port_info);
EXPORT_SYMBOL_GPL(ata_std_bios_param);
EXPORT_SYMBOL_GPL(ata_host_init);
EXPORT_SYMBOL_GPL(ata_host_alloc);
EXPORT_SYMBOL_GPL(ata_host_alloc_pinfo);
EXPORT_SYMBOL_GPL(ata_host_start);
EXPORT_SYMBOL_GPL(ata_host_register);
EXPORT_SYMBOL_GPL(ata_host_activate);
EXPORT_SYMBOL_GPL(ata_host_detach);
EXPORT_SYMBOL_GPL(ata_sg_init);
EXPORT_SYMBOL_GPL(ata_qc_complete);
EXPORT_SYMBOL_GPL(ata_qc_complete_multiple);
EXPORT_SYMBOL_GPL(ata_noop_dev_select);
EXPORT_SYMBOL_GPL(sata_print_link_status);
EXPORT_SYMBOL_GPL(atapi_cmd_type);
EXPORT_SYMBOL_GPL(ata_tf_to_fis);
EXPORT_SYMBOL_GPL(ata_tf_from_fis);
EXPORT_SYMBOL_GPL(ata_pack_xfermask);
EXPORT_SYMBOL_GPL(ata_unpack_xfermask);
EXPORT_SYMBOL_GPL(ata_xfer_mask2mode);
EXPORT_SYMBOL_GPL(ata_xfer_mode2mask);
EXPORT_SYMBOL_GPL(ata_xfer_mode2shift);
EXPORT_SYMBOL_GPL(ata_mode_string);
EXPORT_SYMBOL_GPL(ata_id_xfermask);
EXPORT_SYMBOL_GPL(ata_port_start);
EXPORT_SYMBOL_GPL(ata_do_set_mode);
EXPORT_SYMBOL_GPL(ata_std_qc_defer);
EXPORT_SYMBOL_GPL(ata_noop_qc_prep);
EXPORT_SYMBOL_GPL(ata_port_probe);
EXPORT_SYMBOL_GPL(ata_dev_disable);
EXPORT_SYMBOL_GPL(sata_set_spd);
EXPORT_SYMBOL_GPL(ata_wait_after_reset);
EXPORT_SYMBOL_GPL(sata_link_debounce);
EXPORT_SYMBOL_GPL(sata_link_resume);
EXPORT_SYMBOL_GPL(ata_std_prereset);
EXPORT_SYMBOL_GPL(sata_link_hardreset);
EXPORT_SYMBOL_GPL(sata_std_hardreset);
EXPORT_SYMBOL_GPL(ata_std_postreset);
EXPORT_SYMBOL_GPL(ata_dev_classify);
EXPORT_SYMBOL_GPL(ata_dev_pair);
EXPORT_SYMBOL_GPL(ata_port_disable);
EXPORT_SYMBOL_GPL(ata_ratelimit);
EXPORT_SYMBOL_GPL(ata_wait_register);
EXPORT_SYMBOL_GPL(ata_scsi_ioctl);
EXPORT_SYMBOL_GPL(ata_scsi_queuecmd);
EXPORT_SYMBOL_GPL(ata_scsi_slave_config);
EXPORT_SYMBOL_GPL(ata_scsi_slave_destroy);
EXPORT_SYMBOL_GPL(ata_scsi_change_queue_depth);
EXPORT_SYMBOL_GPL(sata_scr_valid);
EXPORT_SYMBOL_GPL(sata_scr_read);
EXPORT_SYMBOL_GPL(sata_scr_write);
EXPORT_SYMBOL_GPL(sata_scr_write_flush);
EXPORT_SYMBOL_GPL(ata_link_online);
EXPORT_SYMBOL_GPL(ata_link_offline);
#ifdef CONFIG_PM
EXPORT_SYMBOL_GPL(ata_host_suspend);
EXPORT_SYMBOL_GPL(ata_host_resume);
#endif /* CONFIG_PM */
EXPORT_SYMBOL_GPL(ata_id_string);
EXPORT_SYMBOL_GPL(ata_id_c_string);
EXPORT_SYMBOL_GPL(ata_scsi_simulate);

EXPORT_SYMBOL_GPL(ata_pio_need_iordy);
EXPORT_SYMBOL_GPL(ata_timing_find_mode);
EXPORT_SYMBOL_GPL(ata_timing_compute);
EXPORT_SYMBOL_GPL(ata_timing_merge);
EXPORT_SYMBOL_GPL(ata_timing_cycle2mode);

#ifdef CONFIG_PCI
EXPORT_SYMBOL_GPL(pci_test_config_bits);
EXPORT_SYMBOL_GPL(ata_pci_remove_one);
#ifdef CONFIG_PM
EXPORT_SYMBOL_GPL(ata_pci_device_do_suspend);
EXPORT_SYMBOL_GPL(ata_pci_device_do_resume);
EXPORT_SYMBOL_GPL(ata_pci_device_suspend);
EXPORT_SYMBOL_GPL(ata_pci_device_resume);
#endif /* CONFIG_PM */
#endif /* CONFIG_PCI */

EXPORT_SYMBOL_GPL(sata_pmp_qc_defer_cmd_switch);
EXPORT_SYMBOL_GPL(sata_pmp_error_handler);

EXPORT_SYMBOL_GPL(__ata_ehi_push_desc);
EXPORT_SYMBOL_GPL(ata_ehi_push_desc);
EXPORT_SYMBOL_GPL(ata_ehi_clear_desc);
EXPORT_SYMBOL_GPL(ata_port_desc);
#ifdef CONFIG_PCI
EXPORT_SYMBOL_GPL(ata_port_pbar_desc);
#endif /* CONFIG_PCI */
EXPORT_SYMBOL_GPL(ata_port_schedule_eh);
EXPORT_SYMBOL_GPL(ata_link_abort);
EXPORT_SYMBOL_GPL(ata_port_abort);
EXPORT_SYMBOL_GPL(ata_port_freeze);
EXPORT_SYMBOL_GPL(sata_async_notification);
EXPORT_SYMBOL_GPL(ata_eh_freeze_port);
EXPORT_SYMBOL_GPL(ata_eh_thaw_port);
EXPORT_SYMBOL_GPL(ata_eh_qc_complete);
EXPORT_SYMBOL_GPL(ata_eh_qc_retry);
EXPORT_SYMBOL_GPL(ata_do_eh);
EXPORT_SYMBOL_GPL(ata_std_error_handler);

EXPORT_SYMBOL_GPL(ata_cable_40wire);
EXPORT_SYMBOL_GPL(ata_cable_80wire);
EXPORT_SYMBOL_GPL(ata_cable_unknown);
EXPORT_SYMBOL_GPL(ata_cable_ignore);
EXPORT_SYMBOL_GPL(ata_cable_sata);