/*
 *  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/scatterlist.h>
#include <linux/io.h>
#include <linux/async.h>
#include <linux/log2.h>
#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_host.h>
#include <linux/libata.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 = {
        .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,
};

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;
        unsigned int    lflags;
};

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)");

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

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

int atapi_passthru16 = 1;
module_param(atapi_passthru16, int, 0444);
MODULE_PARM_DESC(atapi_passthru16, "Enable ATA_16 passthru for ATAPI devices (0=off, 1=on [default])");

int libata_fua = 0;
module_param_named(fua, libata_fua, int, 0444);
MODULE_PARM_DESC(fua, "FUA support (0=off [default], 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;
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, "Disable the use of ACPI in probe/suspend/resume (0=off [default], 1=on)");

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 (0=off [default], 1=on)");

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


static bool ata_sstatus_online(u32 sstatus)
{
        return (sstatus & 0xf) == 0x3;
}

/**
 *      ata_link_next - link iteration helper
 *      @link: the previous link, NULL to start
 *      @ap: ATA port containing links to iterate
 *      @mode: iteration mode, one of ATA_LITER_*
 *
 *      LOCKING:
 *      Host lock or EH context.
 *
 *      RETURNS:
 *      Pointer to the next link.
 */
struct ata_link *ata_link_next(struct ata_link *link, struct ata_port *ap,
                               enum ata_link_iter_mode mode)
{
        BUG_ON(mode != ATA_LITER_EDGE &&
               mode != ATA_LITER_PMP_FIRST && mode != ATA_LITER_HOST_FIRST);

        /* NULL link indicates start of iteration */
        if (!link)
                switch (mode) {
                case ATA_LITER_EDGE:
                case ATA_LITER_PMP_FIRST:
                        if (sata_pmp_attached(ap))
                                return ap->pmp_link;
                        /* fall through */
                case ATA_LITER_HOST_FIRST:
                        return &ap->link;
                }

        /* we just iterated over the host link, what's next? */
        if (link == &ap->link)
                switch (mode) {
                case ATA_LITER_HOST_FIRST:
                        if (sata_pmp_attached(ap))
                                return ap->pmp_link;
                        /* fall through */
                case ATA_LITER_PMP_FIRST:
                        if (unlikely(ap->slave_link))
                                return ap->slave_link;
                        /* fall through */
                case ATA_LITER_EDGE:
                        return NULL;
                }

        /* slave_link excludes PMP */
        if (unlikely(link == ap->slave_link))
                return NULL;

        /* we were over a PMP link */
        if (++link < ap->pmp_link + ap->nr_pmp_links)
                return link;

        if (mode == ATA_LITER_PMP_FIRST)
                return &ap->link;

        return NULL;
}

/**
 *      ata_dev_next - device iteration helper
 *      @dev: the previous device, NULL to start
 *      @link: ATA link containing devices to iterate
 *      @mode: iteration mode, one of ATA_DITER_*
 *
 *      LOCKING:
 *      Host lock or EH context.
 *
 *      RETURNS:
 *      Pointer to the next device.
 */
struct ata_device *ata_dev_next(struct ata_device *dev, struct ata_link *link,
                                enum ata_dev_iter_mode mode)
{
        BUG_ON(mode != ATA_DITER_ENABLED && mode != ATA_DITER_ENABLED_REVERSE &&
               mode != ATA_DITER_ALL && mode != ATA_DITER_ALL_REVERSE);

        /* NULL dev indicates start of iteration */
        if (!dev)
                switch (mode) {
                case ATA_DITER_ENABLED:
                case ATA_DITER_ALL:
                        dev = link->device;
                        goto check;
                case ATA_DITER_ENABLED_REVERSE:
                case ATA_DITER_ALL_REVERSE:
                        dev = link->device + ata_link_max_devices(link) - 1;
                        goto check;
                }

 next:
        /* move to the next one */
        switch (mode) {
        case ATA_DITER_ENABLED:
        case ATA_DITER_ALL:
                if (++dev < link->device + ata_link_max_devices(link))
                        goto check;
                return NULL;
        case ATA_DITER_ENABLED_REVERSE:
        case ATA_DITER_ALL_REVERSE:
                if (--dev >= link->device)
                        goto check;
                return NULL;
        }

 check:
        if ((mode == ATA_DITER_ENABLED || mode == ATA_DITER_ENABLED_REVERSE) &&
            !ata_dev_enabled(dev))
                goto next;
        return dev;
}

/**
 *      ata_dev_phys_link - find physical link for a device
 *      @dev: ATA device to look up physical link for
 *
 *      Look up physical link which @dev is attached to.  Note that
 *      this is different from @dev->link only when @dev is on slave
 *      link.  For all other cases, it's the same as @dev->link.
 *
 *      LOCKING:
 *      Don't care.
 *
 *      RETURNS:
 *      Pointer to the found physical link.
 */
struct ata_link *ata_dev_phys_link(struct ata_device *dev)
{
        struct ata_port *ap = dev->link->ap;

        if (!ap->slave_link)
                return dev->link;
        if (!dev->devno)
                return &ap->link;
        return ap->slave_link;
}

/**
 *      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_link_limits - force link limits according to libata.force
 *      @link: ATA link of interest
 *
 *      Force link flags and 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.  If the
 *      controller has slave link, device number 16 points to it.
 *
 *      LOCKING:
 *      EH context.
 */
static void ata_force_link_limits(struct ata_link *link)
{
        bool did_spd = false;
        int linkno = link->pmp;
        int i;

        if (ata_is_host_link(link))
                linkno += 15;

        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;

                /* only honor the first spd limit */
                if (!did_spd && fe->param.spd_limit) {
                        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);
                        did_spd = true;
                }

                /* let lflags stack */
                if (fe->param.lflags) {
                        link->flags |= fe->param.lflags;
                        ata_link_printk(link, KERN_NOTICE,
                                        "FORCE: link flag 0x%x forced -> 0x%x\n",
                                        fe->param.lflags, link->flags);
                }
        }
}

/**
 *      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.15/16 for devices attached to host port */
        if (ata_is_host_link(dev->link))
                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.15/16 for devices attached to host port */
        if (ata_is_host_link(dev->link))
                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 |= (u64)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;

                if (!sect) {
                        ata_dev_printk(dev, KERN_WARNING, "device reported "
                                       "invalid CHS sector 0\n");
                        sect = 1; /* oh well */
                }

                block = (cyl * dev->heads + head) * dev->sectors + sect - 1;
        }

        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",
                "6.0 Gbps",
        };

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

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_for_each_link(link, ap, EDGE) {
                        ata_for_each_dev(dev, link, ALL)
                                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.
         * Unfortunately, WDC WD1600JS-62MHB5 (a hard drive) reports
         * SEMB signature.  This is worked around in
         * ata_dev_read_id().
         */
        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)) {
                DPRINTK("found SEMB device by sig (could be ATA device)\n");
                return ATA_DEV_SEMB;
        }

        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;

        BUG_ON(len & 1);

        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;

        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, ATA_ID_LBA_CAPACITY_2);
                else
                        return ata_id_u32(id, ATA_ID_LBA_CAPACITY);
        } else {
                if (ata_id_current_chs_valid(id))
                        return id[ATA_ID_CUR_CYLS] * id[ATA_ID_CUR_HEADS] *
                               id[ATA_ID_CUR_SECTORS];
                else
                        return id[ATA_ID_CYLS] * id[ATA_ID_HEADS] *
                               id[ATA_ID_SECTORS];
        }
}

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 |= ((u64)(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;
        }
        dev->n_native_sectors = native_sectors;

        /* 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_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[ATA_ID_CFA_MODES] >> 0) & 0x7;
                int dma = (id[ATA_ID_CFA_MODES] >> 3) & 0x7;

                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
 *      @data: data for @fn to use
 *      @delay: delay time in msecs 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, msecs_to_jiffies(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;
        int auto_timeout = 0;
        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) {
                if (ata_probe_timeout)
                        timeout = ata_probe_timeout * 1000;
                else {
                        timeout = ata_internal_cmd_timeout(dev, command);
                        auto_timeout = 1;
                }
        }

        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);

        if ((err_mask & AC_ERR_TIMEOUT) && auto_timeout)
                ata_internal_cmd_timed_out(dev, command);

        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)
{
        /* Don't set IORDY if we're preparing for reset.  IORDY may
         * lead to controller lock up on certain controllers if the
         * port is not occupied.  See bko#11703 for details.
         */
        if (adev->link->ap->pflags & ATA_PFLAG_RESETTING)
                return 0;
        /* 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;
        /* CF spec. r4.1 Table 22 says no iordy on PIO5 and PIO6.  */
        if (ata_id_is_cfa(adev->id)
            && (adev->pio_mode == XFER_PIO_5 || adev->pio_mode == XFER_PIO_6))
                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_do_dev_read_id              -       default ID read method
 *      @dev: device
 *      @tf: proposed taskfile
 *      @id: data buffer
 *
 *      Issue the identify taskfile and hand back the buffer containing
 *      identify data. For some RAID controllers and for pre ATA devices
 *      this function is wrapped or replaced by the driver
 */
unsigned int ata_do_dev_read_id(struct ata_device *dev,
                                        struct ata_taskfile *tf, u16 *id)
{
        return ata_exec_internal(dev, tf, NULL, DMA_FROM_DEVICE,
                                     id, sizeof(id[0]) * ATA_ID_WORDS, 0);
}

/**
 *      ata_dev_read_id - Read ID data from the specified device
 *      @dev: target device
 *      @p_class: pointer to class of the target device (may be changed)
 *      @flags: ATA_READID_* flags
 *      @id: buffer to read IDENTIFY data into
 *
 *      Read ID data from the specified device.  ATA_CMD_ID_ATA is
 *      performed on ATA devices and ATA_CMD_ID_ATAPI on ATAPI
 *      devices.  This function also issues ATA_CMD_INIT_DEV_PARAMS
 *      for pre-ATA4 drives.
 *
 *      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;
        bool is_semb = class == ATA_DEV_SEMB;
        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_SEMB:
                class = ATA_DEV_ATA;    /* some hard drives report SEMB sig */
        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;

        if (ap->ops->read_id)
                err_mask = ap->ops->read_id(dev, &tf, id);
        else
                err_mask = ata_do_dev_read_id(dev, &tf, id);

        if (err_mask) {
                if (err_mask & AC_ERR_NODEV_HINT) {
                        ata_dev_printk(dev, KERN_DEBUG,
                                       "NODEV after polling detection\n");
                        return -ENOENT;
                }

                if (is_semb) {
                        ata_dev_printk(dev, KERN_INFO, "IDENTIFY failed on "
                                       "device w/ SEMB sig, disabled\n");
                        /* SEMB is not supported yet */
                        *p_class = ATA_DEV_SEMB_UNSUP;
                        return 0;
                }

                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 int ata_do_link_spd_horkage(struct ata_device *dev)
{
        struct ata_link *plink = ata_dev_phys_link(dev);
        u32 target, target_limit;

        if (!sata_scr_valid(plink))
                return 0;

        if (dev->horkage & ATA_HORKAGE_1_5_GBPS)
                target = 1;
        else
                return 0;

        target_limit = (1 << target) - 1;

        /* if already on stricter limit, no need to push further */
        if (plink->sata_spd_limit <= target_limit)
                return 0;

        plink->sata_spd_limit = target_limit;

        /* Request another EH round by returning -EAGAIN if link is
         * going faster than the target speed.  Forward progress is
         * guaranteed by setting sata_spd_limit to target_limit above.
         */
        if (plink->sata_spd > target) {
                ata_dev_printk(dev, KERN_INFO,
                               "applying link speed limit horkage to %s\n",
                               sata_spd_string(target));
                return -EAGAIN;
        }
        return 0;
}

static inline u8 ata_dev_knobble(struct ata_device *dev)
{
        struct ata_port *ap = dev->link->ap;

        if (ata_dev_blacklisted(dev) & ATA_HORKAGE_BRIDGE_OK)
                return 0;

        return ((ap->cbl == ATA_CBL_SATA) && (!ata_id_is_sata(dev->id)));
}

static int 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);
        unsigned int err_mask;
        char *aa_desc = "";

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

        if (!(dev->horkage & ATA_HORKAGE_BROKEN_FPDMA_AA) &&
                (ap->flags & ATA_FLAG_FPDMA_AA) &&
                ata_id_has_fpdma_aa(dev->id)) {
                err_mask = ata_dev_set_feature(dev, SETFEATURES_SATA_ENABLE,
                        SATA_FPDMA_AA);
                if (err_mask) {
                        ata_dev_printk(dev, KERN_ERR, "failed to enable AA"
                                "(error_mask=0x%x)\n", err_mask);
                        if (err_mask != AC_ERR_DEV) {
                                dev->horkage |= ATA_HORKAGE_BROKEN_FPDMA_AA;
                                return -EIO;
                        }
                } else
                        aa_desc = ", AA";
        }

        if (hdepth >= ddepth)
                snprintf(desc, desc_sz, "NCQ (depth %d)%s", ddepth, aa_desc);
        else
                snprintf(desc, desc_sz, "NCQ (depth %d/%d)%s", hdepth,
                        ddepth, aa_desc);
        return 0;
}

/**
 *      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);

        if (dev->horkage & ATA_HORKAGE_DISABLE) {
                ata_dev_printk(dev, KERN_INFO,
                               "unsupported device, disabling\n");
                ata_dev_disable(dev);
                return 0;
        }

        if ((!atapi_enabled || (ap->flags & ATA_FLAG_NO_ATAPI)) &&
            dev->class == ATA_DEV_ATAPI) {
                ata_dev_printk(dev, KERN_WARNING,
                        "WARNING: ATAPI is %s, device ignored.\n",
                        atapi_enabled ? "not supported with this driver"
                                      : "disabled");
                ata_dev_disable(dev);
                return 0;
        }

        rc = ata_do_link_spd_horkage(dev);
        if (rc)
                return rc;

        /* 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;
        dev->multi_count = 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)) {
                        /* CPRM may make this media unusable */
                        if (id[ATA_ID_CFA_KEY_MGMT] & 1)
                                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);

                /* get current R/W Multiple count setting */
                if ((dev->id[47] >> 8) == 0x80 && (dev->id[59] & 0x100)) {
                        unsigned int max = dev->id[47] & 0xff;
                        unsigned int cnt = dev->id[59] & 0xff;
                        /* only recognize/allow powers of two here */
                        if (is_power_of_2(max) && is_power_of_2(cnt))
                                if (cnt <= max)
                                        dev->multi_count = cnt;
                }

                if (ata_id_has_lba(id)) {
                        const char *lba_desc;
                        char ncq_desc[24];

                        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 */
                        rc = ata_dev_config_ncq(dev, ncq_desc, sizeof(ncq_desc));
                        if (rc)
                                return rc;

                        /* 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) &&
                    (!sata_pmp_attached(ap) ||
                     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");
                }
        }

        if ((dev->horkage & ATA_HORKAGE_FIRMWARE_WARN) && print_info) {
                ata_dev_printk(dev, KERN_WARNING, "WARNING: device requires "
                               "firmware update to be fully functional.\n");
                ata_dev_printk(dev, KERN_WARNING, "         contact the vendor "
                               "or visit http://ata.wiki.kernel.org.\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_for_each_dev(dev, &ap->link, ALL)
                tries[dev->devno] = ATA_PROBE_MAX_TRIES;

 retry:
        ata_for_each_dev(dev, &ap->link, ALL) {
                /* 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_for_each_dev(dev, &ap->link, ALL) {
                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_for_each_dev(dev, &ap->link, ALL_REVERSE) {
                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.  When SATA
         * drives indicate we have a bridge, we don't know which end
         * of the link the bridge is which is a problem.
         */
        ata_for_each_dev(dev, &ap->link, ENABLED)
                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_for_each_dev(dev, &ap->link, ENABLED) {
                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_for_each_dev(dev, &ap->link, ENABLED)
                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, 0);
                        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.
 */
static 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_phys_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
 *      @spd_limit: Additional limit
 *
 *      Adjust SATA spd limit of @link downward.  Note that this
 *      function only adjusts the limit.  The change must be applied
 *      using sata_set_spd().
 *
 *      If @spd_limit is non-zero, the speed is limited to equal to or
 *      lower than @spd_limit if such speed is supported.  If
 *      @spd_limit is slower than any supported speed, only the lowest
 *      supported speed is allowed.
 *
 *      LOCKING:
 *      Inherited from caller.
 *
 *      RETURNS:
 *      0 on success, negative errno on failure
 */
int sata_down_spd_limit(struct ata_link *link, u32 spd_limit)
{
        u32 sstatus, spd, mask;
        int rc, bit;

        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 && ata_sstatus_online(sstatus))
                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 */
        bit = fls(mask) - 1;
        mask &= ~(1 << bit);

        /* 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;

        if (spd_limit) {
                if (mask & ((1 << spd_limit) - 1))
                        mask &= (1 << spd_limit) - 1;
                else {
                        bit = ffs(mask) - 1;
                        mask = 1 << bit;
                }
        }

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

        { XFER_SW_DMA_0, 120,   0,   0,   0, 480, 480, 50, 960,   0 },
        { XFER_SW_DMA_1,  90,   0,   0,   0, 240, 240, 30, 480,   0 },
        { XFER_SW_DMA_2,  60,   0,   0,   0, 120, 120, 20, 240,   0 },

        { XFER_MW_DMA_0,  60,   0,   0,   0, 215, 215, 20, 480,   0 },
        { XFER_MW_DMA_1,  45,   0,   0,   0,  80,  50, 5,  150,   0 },
        { XFER_MW_DMA_2,  25,   0,   0,   0,  70,  25, 5,  120,   0 },
        { XFER_MW_DMA_3,  25,   0,   0,   0,  65,  25, 5,  100,   0 },
        { XFER_MW_DMA_4,  25,   0,   0,   0,  55,  20, 5,   80,   0 },

/*      { XFER_UDMA_SLOW,  0,   0,   0,   0,   0,   0, 0,    0, 150 }, */
        { XFER_UDMA_0,     0,   0,   0,   0,   0,   0, 0,    0, 120 },
        { XFER_UDMA_1,     0,   0,   0,   0,   0,   0, 0,    0,  80 },
        { XFER_UDMA_2,     0,   0,   0,   0,   0,   0, 0,    0,  60 },
        { XFER_UDMA_3,     0,   0,   0,   0,   0,   0, 0,    0,  45 },
        { XFER_UDMA_4,     0,   0,   0,   0,   0,   0, 0,    0,  30 },
        { XFER_UDMA_5,     0,   0,   0,   0,   0,   0, 0,    0,  20 },
        { XFER_UDMA_6,     0,   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->dmack_hold   = EZ(t->dmack_hold * 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_DMACK_HOLD) m->dmack_hold = max(a->dmack_hold, b->dmack_hold);
        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_port *ap = dev->link->ap;
        struct ata_eh_context *ehc = &dev->link->eh_context;
        const bool nosetxfer = dev->horkage & ATA_HORKAGE_NOSETXFER;
        const char *dev_err_whine = "";
        int ign_dev_err = 0;
        unsigned int err_mask = 0;
        int rc;

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

        if (nosetxfer && ap->flags & ATA_FLAG_SATA && ata_id_is_sata(dev->id))
                dev_err_whine = " (SET_XFERMODE skipped)";
        else {
                if (nosetxfer)
                        ata_dev_printk(dev, KERN_WARNING,
                                       "NOSETXFER but PATA detected - can't "
                                       "skip SETXFER, might malfunction\n");
                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;

        if (dev->xfer_shift == ATA_SHIFT_PIO) {
                /* Old CFA may refuse this command, which is just fine */
                if (ata_id_is_cfa(dev->id))
                        ign_dev_err = 1;
                /* Catch several broken garbage emulations plus some pre
                   ATA devices */
                if (ata_id_major_version(dev->id) == 0 &&
                                        dev->pio_mode <= XFER_PIO_2)
                        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 (!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_for_each_dev(dev, link, ENABLED) {
                unsigned long pio_mask, dma_mask;
                unsigned int mode_mask;

                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 (ata_dma_enabled(dev))
                        used_dma = 1;
        }
        if (!found)
                goto out;

        /* step 2: always set host PIO timings */
        ata_for_each_dev(dev, link, ENABLED) {
                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_for_each_dev(dev, link, ENABLED) {
                if (!ata_dma_enabled(dev))
                        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_for_each_dev(dev, link, ENABLED) {
                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 = ata_deadline(start, ATA_TMOUT_FF_WAIT);
        int warned = 0;

        /* Slave readiness can't be tested separately from master.  On
         * M/S emulation configuration, this function should be called
         * only on the master and it will handle both master and slave.
         */
        WARN_ON(link == link->ap->slave_link);

        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.
 */
int ata_wait_after_reset(struct ata_link *link, unsigned long deadline,
                                int (*check_ready)(struct ata_link *link))
{
        msleep(ATA_WAIT_AFTER_RESET);

        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 = params[0];
        unsigned long duration = params[1];
        unsigned long last_jiffies, t;
        u32 last, cur;
        int rc;

        t = ata_deadline(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);
                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,
                                       ata_deadline(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, some PHYs require this even for SRST to work */
        if (!(rc = sata_scr_read(link, SCR_ERROR, &serror)))
                rc = sata_scr_write(link, SCR_ERROR, serror);

        return rc != -EINVAL ? rc : 0;
}

/**
 *      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);
        }

        /* no point in trying softreset on offline link */
        if (ata_phys_link_offline(link))
                ehc->i.action &= ~ATA_EH_SOFTRESET;

        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_phys_link_offline(link))
                goto out;

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

        if (sata_pmp_supported(link->ap) && 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 = ata_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) {
                /* online is set iff link is online && reset succeeded */
                if (online)
                        *online = false;
                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;
}