remote_device.c

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/*
 * This file is provided under a dual BSD/GPLv2 license.  When using or
 * redistributing this file, you may do so under either license.
 *
 * GPL LICENSE SUMMARY
 *
 * Copyright(c) 2008 - 2011 Intel Corporation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * 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; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
 * The full GNU General Public License is included in this distribution
 * in the file called LICENSE.GPL.
 *
 * BSD LICENSE
 *
 * Copyright(c) 2008 - 2011 Intel Corporation. All rights reserved.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in
 *     the documentation and/or other materials provided with the
 *     distribution.
 *   * Neither the name of Intel Corporation nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#include <scsi/sas.h>
#include <linux/bitops.h>
#include "isci.h"
#include "port.h"
#include "remote_device.h"
#include "request.h"
#include "remote_node_context.h"
#include "scu_event_codes.h"
#include "task.h"

#undef C
#define C(a) (#a)
const char *dev_state_name(enum sci_remote_device_states state)
{
    static const char * const strings[] = REMOTE_DEV_STATES;

    return strings[state];
}
#undef C

enum sci_status sci_remote_device_suspend(struct isci_remote_device *idev,
                      enum sci_remote_node_suspension_reasons reason)
{
    return sci_remote_node_context_suspend(&idev->rnc, reason,
                           SCI_SOFTWARE_SUSPEND_EXPECTED_EVENT);
}

static void isci_remote_device_ready(struct isci_host *ihost, struct isci_remote_device *idev)
{
    dev_dbg(&ihost->pdev->dev,
        "%s: idev = %p\n", __func__, idev);

    clear_bit(IDEV_IO_NCQERROR, &idev->flags);
    set_bit(IDEV_IO_READY, &idev->flags);
    if (test_and_clear_bit(IDEV_START_PENDING, &idev->flags))
        wake_up(&ihost->eventq);
}

static enum sci_status sci_remote_device_terminate_req(
    struct isci_host *ihost,
    struct isci_remote_device *idev,
    int check_abort,
    struct isci_request *ireq)
{
    if (!test_bit(IREQ_ACTIVE, &ireq->flags) ||
        (ireq->target_device != idev) ||
        (check_abort && !test_bit(IREQ_PENDING_ABORT, &ireq->flags)))
        return SCI_SUCCESS;

    dev_dbg(&ihost->pdev->dev,
        "%s: idev=%p; flags=%lx; req=%p; req target=%p\n",
        __func__, idev, idev->flags, ireq, ireq->target_device);

    set_bit(IREQ_ABORT_PATH_ACTIVE, &ireq->flags);

    return sci_controller_terminate_request(ihost, idev, ireq);
}

static enum sci_status sci_remote_device_terminate_reqs_checkabort(
    struct isci_remote_device *idev,
    int chk)
{
    struct isci_host *ihost = idev->owning_port->owning_controller;
    enum sci_status status  = SCI_SUCCESS;
    u32 i;

    for (i = 0; i < SCI_MAX_IO_REQUESTS; i++) {
        struct isci_request *ireq = ihost->reqs[i];
        enum sci_status s;

        s = sci_remote_device_terminate_req(ihost, idev, chk, ireq);
        if (s != SCI_SUCCESS)
            status = s;
    }
    return status;
}

static bool isci_compare_suspendcount(
    struct isci_remote_device *idev,
    u32 localcount)
{
    smp_rmb();

    /* Check for a change in the suspend count, or the RNC
     * being destroyed.
     */
    return (localcount != idev->rnc.suspend_count)
        || sci_remote_node_context_is_being_destroyed(&idev->rnc);
}

static bool isci_check_reqterm(
    struct isci_host *ihost,
    struct isci_remote_device *idev,
    struct isci_request *ireq,
    u32 localcount)
{
    unsigned long flags;
    bool res;

    spin_lock_irqsave(&ihost->scic_lock, flags);
    res = isci_compare_suspendcount(idev, localcount)
        && !test_bit(IREQ_ABORT_PATH_ACTIVE, &ireq->flags);
    spin_unlock_irqrestore(&ihost->scic_lock, flags);

    return res;
}

static bool isci_check_devempty(
    struct isci_host *ihost,
    struct isci_remote_device *idev,
    u32 localcount)
{
    unsigned long flags;
    bool res;

    spin_lock_irqsave(&ihost->scic_lock, flags);
    res = isci_compare_suspendcount(idev, localcount)
        && idev->started_request_count == 0;
    spin_unlock_irqrestore(&ihost->scic_lock, flags);

    return res;
}

enum sci_status isci_remote_device_terminate_requests(
    struct isci_host *ihost,
    struct isci_remote_device *idev,
    struct isci_request *ireq)
{
    enum sci_status status = SCI_SUCCESS;
    unsigned long flags;
    u32 rnc_suspend_count;

    spin_lock_irqsave(&ihost->scic_lock, flags);

    if (isci_get_device(idev) == NULL) {
        dev_dbg(&ihost->pdev->dev, "%s: failed isci_get_device(idev=%p)\n",
            __func__, idev);
        spin_unlock_irqrestore(&ihost->scic_lock, flags);
        status = SCI_FAILURE;
    } else {
        /* If already suspended, don't wait for another suspension. */
        smp_rmb();
        rnc_suspend_count
            = sci_remote_node_context_is_suspended(&idev->rnc)
                ? 0 : idev->rnc.suspend_count;

        dev_dbg(&ihost->pdev->dev,
            "%s: idev=%p, ireq=%p; started_request_count=%d, "
                "rnc_suspend_count=%d, rnc.suspend_count=%d"
                "about to wait\n",
            __func__, idev, ireq, idev->started_request_count,
            rnc_suspend_count, idev->rnc.suspend_count);

        #define MAX_SUSPEND_MSECS 10000
        if (ireq) {
            /* Terminate a specific TC. */
            set_bit(IREQ_NO_AUTO_FREE_TAG, &ireq->flags);
            sci_remote_device_terminate_req(ihost, idev, 0, ireq);
            spin_unlock_irqrestore(&ihost->scic_lock, flags);
            if (!wait_event_timeout(ihost->eventq,
                        isci_check_reqterm(ihost, idev, ireq,
                                   rnc_suspend_count),
                        msecs_to_jiffies(MAX_SUSPEND_MSECS))) {

                dev_warn(&ihost->pdev->dev, "%s host%d timeout single\n",
                     __func__, ihost->id);
                dev_dbg(&ihost->pdev->dev,
                     "%s: ******* Timeout waiting for "
                     "suspend; idev=%p, current state %s; "
                     "started_request_count=%d, flags=%lx\n\t"
                     "rnc_suspend_count=%d, rnc.suspend_count=%d "
                     "RNC: current state %s, current "
                     "suspend_type %x dest state %d;\n"
                     "ireq=%p, ireq->flags = %lx\n",
                     __func__, idev,
                     dev_state_name(idev->sm.current_state_id),
                     idev->started_request_count, idev->flags,
                     rnc_suspend_count, idev->rnc.suspend_count,
                     rnc_state_name(idev->rnc.sm.current_state_id),
                     idev->rnc.suspend_type,
                     idev->rnc.destination_state,
                     ireq, ireq->flags);
            }
            spin_lock_irqsave(&ihost->scic_lock, flags);
            clear_bit(IREQ_NO_AUTO_FREE_TAG, &ireq->flags);
            if (!test_bit(IREQ_ABORT_PATH_ACTIVE, &ireq->flags))
                isci_free_tag(ihost, ireq->io_tag);
            spin_unlock_irqrestore(&ihost->scic_lock, flags);
        } else {
            /* Terminate all TCs. */
            sci_remote_device_terminate_requests(idev);
            spin_unlock_irqrestore(&ihost->scic_lock, flags);
            if (!wait_event_timeout(ihost->eventq,
                        isci_check_devempty(ihost, idev,
                                    rnc_suspend_count),
                        msecs_to_jiffies(MAX_SUSPEND_MSECS))) {

                dev_warn(&ihost->pdev->dev, "%s host%d timeout all\n",
                     __func__, ihost->id);
                dev_dbg(&ihost->pdev->dev,
                    "%s: ******* Timeout waiting for "
                    "suspend; idev=%p, current state %s; "
                    "started_request_count=%d, flags=%lx\n\t"
                    "rnc_suspend_count=%d, "
                    "RNC: current state %s, "
                    "rnc.suspend_count=%d, current "
                    "suspend_type %x dest state %d\n",
                    __func__, idev,
                    dev_state_name(idev->sm.current_state_id),
                    idev->started_request_count, idev->flags,
                    rnc_suspend_count,
                    rnc_state_name(idev->rnc.sm.current_state_id),
                    idev->rnc.suspend_count,
                    idev->rnc.suspend_type,
                    idev->rnc.destination_state);
            }
        }
        dev_dbg(&ihost->pdev->dev, "%s: idev=%p, wait done\n",
            __func__, idev);
        isci_put_device(idev);
    }
    return status;
}

static void isci_remote_device_not_ready(struct isci_host *ihost,
                     struct isci_remote_device *idev,
                     u32 reason)
{
    dev_dbg(&ihost->pdev->dev,
        "%s: isci_device = %p; reason = %d\n", __func__, idev, reason);

    switch (reason) {
    case SCIC_REMOTE_DEVICE_NOT_READY_SATA_SDB_ERROR_FIS_RECEIVED:
        set_bit(IDEV_IO_NCQERROR, &idev->flags);

        /* Suspend the remote device so the I/O can be terminated. */
        sci_remote_device_suspend(idev, SCI_SW_SUSPEND_NORMAL);

        /* Kill all outstanding requests for the device. */
        sci_remote_device_terminate_requests(idev);

        /* Fall through into the default case... */
    default:
        clear_bit(IDEV_IO_READY, &idev->flags);
        break;
    }
}

/* called once the remote node context is ready to be freed.
 * The remote device can now report that its stop operation is complete. none
 */
static void rnc_destruct_done(void *_dev)
{
    struct isci_remote_device *idev = _dev;

    BUG_ON(idev->started_request_count != 0);
    sci_change_state(&idev->sm, SCI_DEV_STOPPED);
}

enum sci_status sci_remote_device_terminate_requests(
    struct isci_remote_device *idev)
{
    return sci_remote_device_terminate_reqs_checkabort(idev, 0);
}

enum sci_status sci_remote_device_stop(struct isci_remote_device *idev,
                    u32 timeout)
{
    struct sci_base_state_machine *sm = &idev->sm;
    enum sci_remote_device_states state = sm->current_state_id;

    switch (state) {
    case SCI_DEV_INITIAL:
    case SCI_DEV_FAILED:
    case SCI_DEV_FINAL:
    default:
        dev_warn(scirdev_to_dev(idev), "%s: in wrong state: %s\n",
             __func__, dev_state_name(state));
        return SCI_FAILURE_INVALID_STATE;
    case SCI_DEV_STOPPED:
        return SCI_SUCCESS;
    case SCI_DEV_STARTING:
        /* device not started so there had better be no requests */
        BUG_ON(idev->started_request_count != 0);
        sci_remote_node_context_destruct(&idev->rnc,
                              rnc_destruct_done, idev);
        /* Transition to the stopping state and wait for the
         * remote node to complete being posted and invalidated.
         */
        sci_change_state(sm, SCI_DEV_STOPPING);
        return SCI_SUCCESS;
    case SCI_DEV_READY:
    case SCI_STP_DEV_IDLE:
    case SCI_STP_DEV_CMD:
    case SCI_STP_DEV_NCQ:
    case SCI_STP_DEV_NCQ_ERROR:
    case SCI_STP_DEV_AWAIT_RESET:
    case SCI_SMP_DEV_IDLE:
    case SCI_SMP_DEV_CMD:
        sci_change_state(sm, SCI_DEV_STOPPING);
        if (idev->started_request_count == 0)
            sci_remote_node_context_destruct(&idev->rnc,
                             rnc_destruct_done,
                             idev);
        else {
            sci_remote_device_suspend(
                idev, SCI_SW_SUSPEND_LINKHANG_DETECT);
            sci_remote_device_terminate_requests(idev);
        }
        return SCI_SUCCESS;
    case SCI_DEV_STOPPING:
        /* All requests should have been terminated, but if there is an
         * attempt to stop a device already in the stopping state, then
         * try again to terminate.
         */
        return sci_remote_device_terminate_requests(idev);
    case SCI_DEV_RESETTING:
        sci_change_state(sm, SCI_DEV_STOPPING);
        return SCI_SUCCESS;
    }
}

enum sci_status sci_remote_device_reset(struct isci_remote_device *idev)
{
    struct sci_base_state_machine *sm = &idev->sm;
    enum sci_remote_device_states state = sm->current_state_id;

    switch (state) {
    case SCI_DEV_INITIAL:
    case SCI_DEV_STOPPED:
    case SCI_DEV_STARTING:
    case SCI_SMP_DEV_IDLE:
    case SCI_SMP_DEV_CMD:
    case SCI_DEV_STOPPING:
    case SCI_DEV_FAILED:
    case SCI_DEV_RESETTING:
    case SCI_DEV_FINAL:
    default:
        dev_warn(scirdev_to_dev(idev), "%s: in wrong state: %s\n",
             __func__, dev_state_name(state));
        return SCI_FAILURE_INVALID_STATE;
    case SCI_DEV_READY:
    case SCI_STP_DEV_IDLE:
    case SCI_STP_DEV_CMD:
    case SCI_STP_DEV_NCQ:
    case SCI_STP_DEV_NCQ_ERROR:
    case SCI_STP_DEV_AWAIT_RESET:
        sci_change_state(sm, SCI_DEV_RESETTING);
        return SCI_SUCCESS;
    }
}

enum sci_status sci_remote_device_reset_complete(struct isci_remote_device *idev)
{
    struct sci_base_state_machine *sm = &idev->sm;
    enum sci_remote_device_states state = sm->current_state_id;

    if (state != SCI_DEV_RESETTING) {
        dev_warn(scirdev_to_dev(idev), "%s: in wrong state: %s\n",
             __func__, dev_state_name(state));
        return SCI_FAILURE_INVALID_STATE;
    }

    sci_change_state(sm, SCI_DEV_READY);
    return SCI_SUCCESS;
}

enum sci_status sci_remote_device_frame_handler(struct isci_remote_device *idev,
                             u32 frame_index)
{
    struct sci_base_state_machine *sm = &idev->sm;
    enum sci_remote_device_states state = sm->current_state_id;
    struct isci_host *ihost = idev->owning_port->owning_controller;
    enum sci_status status;

    switch (state) {
    case SCI_DEV_INITIAL:
    case SCI_DEV_STOPPED:
    case SCI_DEV_STARTING:
    case SCI_STP_DEV_IDLE:
    case SCI_SMP_DEV_IDLE:
    case SCI_DEV_FINAL:
    default:
        dev_warn(scirdev_to_dev(idev), "%s: in wrong state: %s\n",
             __func__, dev_state_name(state));
        /* Return the frame back to the controller */
        sci_controller_release_frame(ihost, frame_index);
        return SCI_FAILURE_INVALID_STATE;
    case SCI_DEV_READY:
    case SCI_STP_DEV_NCQ_ERROR:
    case SCI_STP_DEV_AWAIT_RESET:
    case SCI_DEV_STOPPING:
    case SCI_DEV_FAILED:
    case SCI_DEV_RESETTING: {
        struct isci_request *ireq;
        struct ssp_frame_hdr hdr;
        void *frame_header;
        ssize_t word_cnt;

        status = sci_unsolicited_frame_control_get_header(&ihost->uf_control,
                                       frame_index,
                                       &frame_header);
        if (status != SCI_SUCCESS)
            return status;

        word_cnt = sizeof(hdr) / sizeof(u32);
        sci_swab32_cpy(&hdr, frame_header, word_cnt);

        ireq = sci_request_by_tag(ihost, be16_to_cpu(hdr.tag));
        if (ireq && ireq->target_device == idev) {
            /* The IO request is now in charge of releasing the frame */
            status = sci_io_request_frame_handler(ireq, frame_index);
        } else {
            /* We could not map this tag to a valid IO
             * request Just toss the frame and continue
             */
            sci_controller_release_frame(ihost, frame_index);
        }
        break;
    }
    case SCI_STP_DEV_NCQ: {
        struct dev_to_host_fis *hdr;

        status = sci_unsolicited_frame_control_get_header(&ihost->uf_control,
                                       frame_index,
                                       (void **)&hdr);
        if (status != SCI_SUCCESS)
            return status;

        if (hdr->fis_type == FIS_SETDEVBITS &&
            (hdr->status & ATA_ERR)) {
            idev->not_ready_reason = SCIC_REMOTE_DEVICE_NOT_READY_SATA_SDB_ERROR_FIS_RECEIVED;

            /* TODO Check sactive and complete associated IO if any. */
            sci_change_state(sm, SCI_STP_DEV_NCQ_ERROR);
        } else if (hdr->fis_type == FIS_REGD2H &&
               (hdr->status & ATA_ERR)) {
            /*
             * Some devices return D2H FIS when an NCQ error is detected.
             * Treat this like an SDB error FIS ready reason.
             */
            idev->not_ready_reason = SCIC_REMOTE_DEVICE_NOT_READY_SATA_SDB_ERROR_FIS_RECEIVED;
            sci_change_state(&idev->sm, SCI_STP_DEV_NCQ_ERROR);
        } else
            status = SCI_FAILURE;

        sci_controller_release_frame(ihost, frame_index);
        break;
    }
    case SCI_STP_DEV_CMD:
    case SCI_SMP_DEV_CMD:
        /* The device does not process any UF received from the hardware while
         * in this state.  All unsolicited frames are forwarded to the io request
         * object.
         */
        status = sci_io_request_frame_handler(idev->working_request, frame_index);
        break;
    }

    return status;
}

static bool is_remote_device_ready(struct isci_remote_device *idev)
{

    struct sci_base_state_machine *sm = &idev->sm;
    enum sci_remote_device_states state = sm->current_state_id;

    switch (state) {
    case SCI_DEV_READY:
    case SCI_STP_DEV_IDLE:
    case SCI_STP_DEV_CMD:
    case SCI_STP_DEV_NCQ:
    case SCI_STP_DEV_NCQ_ERROR:
    case SCI_STP_DEV_AWAIT_RESET:
    case SCI_SMP_DEV_IDLE:
    case SCI_SMP_DEV_CMD:
        return true;
    default:
        return false;
    }
}

/*
 * called once the remote node context has transisitioned to a ready
 * state (after suspending RX and/or TX due to early D2H fis)
 */
static void atapi_remote_device_resume_done(void *_dev)
{
    struct isci_remote_device *idev = _dev;
    struct isci_request *ireq = idev->working_request;

    sci_change_state(&ireq->sm, SCI_REQ_COMPLETED);
}

enum sci_status sci_remote_device_event_handler(struct isci_remote_device *idev,
                             u32 event_code)
{
    enum sci_status status;
    struct sci_base_state_machine *sm = &idev->sm;
    enum sci_remote_device_states state = sm->current_state_id;

    switch (scu_get_event_type(event_code)) {
    case SCU_EVENT_TYPE_RNC_OPS_MISC:
    case SCU_EVENT_TYPE_RNC_SUSPEND_TX:
    case SCU_EVENT_TYPE_RNC_SUSPEND_TX_RX:
        status = sci_remote_node_context_event_handler(&idev->rnc, event_code);
        break;
    case SCU_EVENT_TYPE_PTX_SCHEDULE_EVENT:
        if (scu_get_event_code(event_code) == SCU_EVENT_IT_NEXUS_TIMEOUT) {
            status = SCI_SUCCESS;

            /* Suspend the associated RNC */
            sci_remote_device_suspend(idev, SCI_SW_SUSPEND_NORMAL);

            dev_dbg(scirdev_to_dev(idev),
                "%s: device: %p event code: %x: %s\n",
                __func__, idev, event_code,
                is_remote_device_ready(idev)
                ? "I_T_Nexus_Timeout event"
                : "I_T_Nexus_Timeout event in wrong state");

            break;
        }
    /* Else, fall through and treat as unhandled... */
    default:
        dev_dbg(scirdev_to_dev(idev),
            "%s: device: %p event code: %x: %s\n",
            __func__, idev, event_code,
            is_remote_device_ready(idev)
            ? "unexpected event"
            : "unexpected event in wrong state");
        status = SCI_FAILURE_INVALID_STATE;
        break;
    }

    if (status != SCI_SUCCESS)
        return status;

    /* Decode device-specific states that may require an RNC resume during
     * normal operation.  When the abort path is active, these resumes are
     * managed when the abort path exits.
     */
    if (state == SCI_STP_DEV_ATAPI_ERROR) {
        /* For ATAPI error state resume the RNC right away. */
        if (scu_get_event_type(event_code) == SCU_EVENT_TYPE_RNC_SUSPEND_TX ||
            scu_get_event_type(event_code) == SCU_EVENT_TYPE_RNC_SUSPEND_TX_RX) {
            return sci_remote_node_context_resume(&idev->rnc,
                                  atapi_remote_device_resume_done,
                                  idev);
        }
    }

    if (state == SCI_STP_DEV_IDLE) {

        /* We pick up suspension events to handle specifically to this
         * state. We resume the RNC right away.
         */
        if (scu_get_event_type(event_code) == SCU_EVENT_TYPE_RNC_SUSPEND_TX ||
            scu_get_event_type(event_code) == SCU_EVENT_TYPE_RNC_SUSPEND_TX_RX)
            status = sci_remote_node_context_resume(&idev->rnc, NULL, NULL);
    }

    return status;
}

static void sci_remote_device_start_request(struct isci_remote_device *idev,
                         struct isci_request *ireq,
                         enum sci_status status)
{
    struct isci_port *iport = idev->owning_port;

    /* cleanup requests that failed after starting on the port */
    if (status != SCI_SUCCESS)
        sci_port_complete_io(iport, idev, ireq);
    else {
        kref_get(&idev->kref);
        idev->started_request_count++;
    }
}

enum sci_status sci_remote_device_start_io(struct isci_host *ihost,
                        struct isci_remote_device *idev,
                        struct isci_request *ireq)
{
    struct sci_base_state_machine *sm = &idev->sm;
    enum sci_remote_device_states state = sm->current_state_id;
    struct isci_port *iport = idev->owning_port;
    enum sci_status status;

    switch (state) {
    case SCI_DEV_INITIAL:
    case SCI_DEV_STOPPED:
    case SCI_DEV_STARTING:
    case SCI_STP_DEV_NCQ_ERROR:
    case SCI_DEV_STOPPING:
    case SCI_DEV_FAILED:
    case SCI_DEV_RESETTING:
    case SCI_DEV_FINAL:
    default:
        dev_warn(scirdev_to_dev(idev), "%s: in wrong state: %s\n",
             __func__, dev_state_name(state));
        return SCI_FAILURE_INVALID_STATE;
    case SCI_DEV_READY:
        /* attempt to start an io request for this device object. The remote
         * device object will issue the start request for the io and if
         * successful it will start the request for the port object then
         * increment its own request count.
         */
        status = sci_port_start_io(iport, idev, ireq);
        if (status != SCI_SUCCESS)
            return status;

        status = sci_remote_node_context_start_io(&idev->rnc, ireq);
        if (status != SCI_SUCCESS)
            break;

        status = sci_request_start(ireq);
        break;
    case SCI_STP_DEV_IDLE: {
        /* handle the start io operation for a sata device that is in
         * the command idle state. - Evalute the type of IO request to
         * be started - If its an NCQ request change to NCQ substate -
         * If its any other command change to the CMD substate
         *
         * If this is a softreset we may want to have a different
         * substate.
         */
        enum sci_remote_device_states new_state;
        struct sas_task *task = isci_request_access_task(ireq);

        status = sci_port_start_io(iport, idev, ireq);
        if (status != SCI_SUCCESS)
            return status;

        status = sci_remote_node_context_start_io(&idev->rnc, ireq);
        if (status != SCI_SUCCESS)
            break;

        status = sci_request_start(ireq);
        if (status != SCI_SUCCESS)
            break;

        if (task->ata_task.use_ncq)
            new_state = SCI_STP_DEV_NCQ;
        else {
            idev->working_request = ireq;
            new_state = SCI_STP_DEV_CMD;
        }
        sci_change_state(sm, new_state);
        break;
    }
    case SCI_STP_DEV_NCQ: {
        struct sas_task *task = isci_request_access_task(ireq);

        if (task->ata_task.use_ncq) {
            status = sci_port_start_io(iport, idev, ireq);
            if (status != SCI_SUCCESS)
                return status;

            status = sci_remote_node_context_start_io(&idev->rnc, ireq);
            if (status != SCI_SUCCESS)
                break;

            status = sci_request_start(ireq);
        } else
            return SCI_FAILURE_INVALID_STATE;
        break;
    }
    case SCI_STP_DEV_AWAIT_RESET:
        return SCI_FAILURE_REMOTE_DEVICE_RESET_REQUIRED;
    case SCI_SMP_DEV_IDLE:
        status = sci_port_start_io(iport, idev, ireq);
        if (status != SCI_SUCCESS)
            return status;

        status = sci_remote_node_context_start_io(&idev->rnc, ireq);
        if (status != SCI_SUCCESS)
            break;

        status = sci_request_start(ireq);
        if (status != SCI_SUCCESS)
            break;

        idev->working_request = ireq;
        sci_change_state(&idev->sm, SCI_SMP_DEV_CMD);
        break;
    case SCI_STP_DEV_CMD:
    case SCI_SMP_DEV_CMD:
        /* device is already handling a command it can not accept new commands
         * until this one is complete.
         */
        return SCI_FAILURE_INVALID_STATE;
    }

    sci_remote_device_start_request(idev, ireq, status);
    return status;
}

static enum sci_status common_complete_io(struct isci_port *iport,
                      struct isci_remote_device *idev,
                      struct isci_request *ireq)
{
    enum sci_status status;

    status = sci_request_complete(ireq);
    if (status != SCI_SUCCESS)
        return status;

    status = sci_port_complete_io(iport, idev, ireq);
    if (status != SCI_SUCCESS)
        return status;

    sci_remote_device_decrement_request_count(idev);
    return status;
}

enum sci_status sci_remote_device_complete_io(struct isci_host *ihost,
                           struct isci_remote_device *idev,
                           struct isci_request *ireq)
{
    struct sci_base_state_machine *sm = &idev->sm;
    enum sci_remote_device_states state = sm->current_state_id;
    struct isci_port *iport = idev->owning_port;
    enum sci_status status;

    switch (state) {
    case SCI_DEV_INITIAL:
    case SCI_DEV_STOPPED:
    case SCI_DEV_STARTING:
    case SCI_STP_DEV_IDLE:
    case SCI_SMP_DEV_IDLE:
    case SCI_DEV_FAILED:
    case SCI_DEV_FINAL:
    default:
        dev_warn(scirdev_to_dev(idev), "%s: in wrong state: %s\n",
             __func__, dev_state_name(state));
        return SCI_FAILURE_INVALID_STATE;
    case SCI_DEV_READY:
    case SCI_STP_DEV_AWAIT_RESET:
    case SCI_DEV_RESETTING:
        status = common_complete_io(iport, idev, ireq);
        break;
    case SCI_STP_DEV_CMD:
    case SCI_STP_DEV_NCQ:
    case SCI_STP_DEV_NCQ_ERROR:
    case SCI_STP_DEV_ATAPI_ERROR:
        status = common_complete_io(iport, idev, ireq);
        if (status != SCI_SUCCESS)
            break;

        if (ireq->sci_status == SCI_FAILURE_REMOTE_DEVICE_RESET_REQUIRED) {
            /* This request causes hardware error, device needs to be Lun Reset.
             * So here we force the state machine to IDLE state so the rest IOs
             * can reach RNC state handler, these IOs will be completed by RNC with
             * status of "DEVICE_RESET_REQUIRED", instead of "INVALID STATE".
             */
            sci_change_state(sm, SCI_STP_DEV_AWAIT_RESET);
        } else if (idev->started_request_count == 0)
            sci_change_state(sm, SCI_STP_DEV_IDLE);
        break;
    case SCI_SMP_DEV_CMD:
        status = common_complete_io(iport, idev, ireq);
        if (status != SCI_SUCCESS)
            break;
        sci_change_state(sm, SCI_SMP_DEV_IDLE);
        break;
    case SCI_DEV_STOPPING:
        status = common_complete_io(iport, idev, ireq);
        if (status != SCI_SUCCESS)
            break;

        if (idev->started_request_count == 0)
            sci_remote_node_context_destruct(&idev->rnc,
                             rnc_destruct_done,
                             idev);
        break;
    }

    if (status != SCI_SUCCESS)
        dev_err(scirdev_to_dev(idev),
            "%s: Port:0x%p Device:0x%p Request:0x%p Status:0x%x "
            "could not complete\n", __func__, iport,
            idev, ireq, status);
    else
        isci_put_device(idev);

    return status;
}

static void sci_remote_device_continue_request(void *dev)
{
    struct isci_remote_device *idev = dev;

    /* we need to check if this request is still valid to continue. */
    if (idev->working_request)
        sci_controller_continue_io(idev->working_request);
}

enum sci_status sci_remote_device_start_task(struct isci_host *ihost,
                          struct isci_remote_device *idev,
                          struct isci_request *ireq)
{
    struct sci_base_state_machine *sm = &idev->sm;
    enum sci_remote_device_states state = sm->current_state_id;
    struct isci_port *iport = idev->owning_port;
    enum sci_status status;

    switch (state) {
    case SCI_DEV_INITIAL:
    case SCI_DEV_STOPPED:
    case SCI_DEV_STARTING:
    case SCI_SMP_DEV_IDLE:
    case SCI_SMP_DEV_CMD:
    case SCI_DEV_STOPPING:
    case SCI_DEV_FAILED:
    case SCI_DEV_RESETTING:
    case SCI_DEV_FINAL:
    default:
        dev_warn(scirdev_to_dev(idev), "%s: in wrong state: %s\n",
             __func__, dev_state_name(state));
        return SCI_FAILURE_INVALID_STATE;
    case SCI_STP_DEV_IDLE:
    case SCI_STP_DEV_CMD:
    case SCI_STP_DEV_NCQ:
    case SCI_STP_DEV_NCQ_ERROR:
    case SCI_STP_DEV_AWAIT_RESET:
        status = sci_port_start_io(iport, idev, ireq);
        if (status != SCI_SUCCESS)
            return status;

        status = sci_request_start(ireq);
        if (status != SCI_SUCCESS)
            goto out;

        /* Note: If the remote device state is not IDLE this will
         * replace the request that probably resulted in the task
         * management request.
         */
        idev->working_request = ireq;
        sci_change_state(sm, SCI_STP_DEV_CMD);

        /* The remote node context must cleanup the TCi to NCQ mapping
         * table.  The only way to do this correctly is to either write
         * to the TLCR register or to invalidate and repost the RNC. In
         * either case the remote node context state machine will take
         * the correct action when the remote node context is suspended
         * and later resumed.
         */
        sci_remote_device_suspend(idev,
                      SCI_SW_SUSPEND_LINKHANG_DETECT);

        status = sci_remote_node_context_start_task(&idev->rnc, ireq,
                sci_remote_device_continue_request, idev);

    out:
        sci_remote_device_start_request(idev, ireq, status);
        /* We need to let the controller start request handler know that
         * it can't post TC yet. We will provide a callback function to
         * post TC when RNC gets resumed.
         */
        return SCI_FAILURE_RESET_DEVICE_PARTIAL_SUCCESS;
    case SCI_DEV_READY:
        status = sci_port_start_io(iport, idev, ireq);
        if (status != SCI_SUCCESS)
            return status;

        /* Resume the RNC as needed: */
        status = sci_remote_node_context_start_task(&idev->rnc, ireq,
                                NULL, NULL);
        if (status != SCI_SUCCESS)
            break;

        status = sci_request_start(ireq);
        break;
    }
    sci_remote_device_start_request(idev, ireq, status);

    return status;
}

void sci_remote_device_post_request(struct isci_remote_device *idev, u32 request)
{
    struct isci_port *iport = idev->owning_port;
    u32 context;

    context = request |
          (ISCI_PEG << SCU_CONTEXT_COMMAND_PROTOCOL_ENGINE_GROUP_SHIFT) |
          (iport->physical_port_index << SCU_CONTEXT_COMMAND_LOGICAL_PORT_SHIFT) |
          idev->rnc.remote_node_index;

    sci_controller_post_request(iport->owning_controller, context);
}

/* called once the remote node context has transisitioned to a
 * ready state.  This is the indication that the remote device object can also
 * transition to ready.
 */
static void remote_device_resume_done(void *_dev)
{
    struct isci_remote_device *idev = _dev;

    if (is_remote_device_ready(idev))
        return;

    /* go 'ready' if we are not already in a ready state */
    sci_change_state(&idev->sm, SCI_DEV_READY);
}

static void sci_stp_remote_device_ready_idle_substate_resume_complete_handler(void *_dev)
{
    struct isci_remote_device *idev = _dev;
    struct isci_host *ihost = idev->owning_port->owning_controller;

    /* For NCQ operation we do not issue a isci_remote_device_not_ready().
     * As a result, avoid sending the ready notification.
     */
    if (idev->sm.previous_state_id != SCI_STP_DEV_NCQ)
        isci_remote_device_ready(ihost, idev);
}

static void sci_remote_device_initial_state_enter(struct sci_base_state_machine *sm)
{
    struct isci_remote_device *idev = container_of(sm, typeof(*idev), sm);

    /* Initial state is a transitional state to the stopped state */
    sci_change_state(&idev->sm, SCI_DEV_STOPPED);
}

static enum sci_status sci_remote_device_destruct(struct isci_remote_device *idev)
{
    struct sci_base_state_machine *sm = &idev->sm;
    enum sci_remote_device_states state = sm->current_state_id;
    struct isci_host *ihost;

    if (state != SCI_DEV_STOPPED) {
        dev_warn(scirdev_to_dev(idev), "%s: in wrong state: %s\n",
             __func__, dev_state_name(state));
        return SCI_FAILURE_INVALID_STATE;
    }

    ihost = idev->owning_port->owning_controller;
    sci_controller_free_remote_node_context(ihost, idev,
                             idev->rnc.remote_node_index);
    idev->rnc.remote_node_index = SCIC_SDS_REMOTE_NODE_CONTEXT_INVALID_INDEX;
    sci_change_state(sm, SCI_DEV_FINAL);

    return SCI_SUCCESS;
}

static void isci_remote_device_deconstruct(struct isci_host *ihost, struct isci_remote_device *idev)
{
    dev_dbg(&ihost->pdev->dev,
        "%s: isci_device = %p\n", __func__, idev);

    /* There should not be any outstanding io's. All paths to
     * here should go through isci_remote_device_nuke_requests.
     * If we hit this condition, we will need a way to complete
     * io requests in process */
    BUG_ON(idev->started_request_count > 0);

    sci_remote_device_destruct(idev);
    list_del_init(&idev->node);
    isci_put_device(idev);
}

static void sci_remote_device_stopped_state_enter(struct sci_base_state_machine *sm)
{
    struct isci_remote_device *idev = container_of(sm, typeof(*idev), sm);
    struct isci_host *ihost = idev->owning_port->owning_controller;
    u32 prev_state;

    /* If we are entering from the stopping state let the SCI User know that
     * the stop operation has completed.
     */
    prev_state = idev->sm.previous_state_id;
    if (prev_state == SCI_DEV_STOPPING)
        isci_remote_device_deconstruct(ihost, idev);

    sci_controller_remote_device_stopped(ihost, idev);
}

static void sci_remote_device_starting_state_enter(struct sci_base_state_machine *sm)
{
    struct isci_remote_device *idev = container_of(sm, typeof(*idev), sm);
    struct isci_host *ihost = idev->owning_port->owning_controller;

    isci_remote_device_not_ready(ihost, idev,
                     SCIC_REMOTE_DEVICE_NOT_READY_START_REQUESTED);
}

static void sci_remote_device_ready_state_enter(struct sci_base_state_machine *sm)
{
    struct isci_remote_device *idev = container_of(sm, typeof(*idev), sm);
    struct isci_host *ihost = idev->owning_port->owning_controller;
    struct domain_device *dev = idev->domain_dev;

    if (dev->dev_type == SATA_DEV || (dev->tproto & SAS_PROTOCOL_SATA)) {
        sci_change_state(&idev->sm, SCI_STP_DEV_IDLE);
    } else if (dev_is_expander(dev)) {
        sci_change_state(&idev->sm, SCI_SMP_DEV_IDLE);
    } else
        isci_remote_device_ready(ihost, idev);
}

static void sci_remote_device_ready_state_exit(struct sci_base_state_machine *sm)
{
    struct isci_remote_device *idev = container_of(sm, typeof(*idev), sm);
    struct domain_device *dev = idev->domain_dev;

    if (dev->dev_type == SAS_END_DEV) {
        struct isci_host *ihost = idev->owning_port->owning_controller;

        isci_remote_device_not_ready(ihost, idev,
                         SCIC_REMOTE_DEVICE_NOT_READY_STOP_REQUESTED);
    }
}

static void sci_remote_device_resetting_state_enter(struct sci_base_state_machine *sm)
{
    struct isci_remote_device *idev = container_of(sm, typeof(*idev), sm);
    struct isci_host *ihost = idev->owning_port->owning_controller;

    dev_dbg(&ihost->pdev->dev,
        "%s: isci_device = %p\n", __func__, idev);

    sci_remote_device_suspend(idev, SCI_SW_SUSPEND_LINKHANG_DETECT);
}

static void sci_remote_device_resetting_state_exit(struct sci_base_state_machine *sm)
{
    struct isci_remote_device *idev = container_of(sm, typeof(*idev), sm);
    struct isci_host *ihost = idev->owning_port->owning_controller;

    dev_dbg(&ihost->pdev->dev,
        "%s: isci_device = %p\n", __func__, idev);

    sci_remote_node_context_resume(&idev->rnc, NULL, NULL);
}

static void sci_stp_remote_device_ready_idle_substate_enter(struct sci_base_state_machine *sm)
{
    struct isci_remote_device *idev = container_of(sm, typeof(*idev), sm);

    idev->working_request = NULL;
    if (sci_remote_node_context_is_ready(&idev->rnc)) {
        /*
         * Since the RNC is ready, it's alright to finish completion
         * processing (e.g. signal the remote device is ready). */
        sci_stp_remote_device_ready_idle_substate_resume_complete_handler(idev);
    } else {
        sci_remote_node_context_resume(&idev->rnc,
            sci_stp_remote_device_ready_idle_substate_resume_complete_handler,
            idev);
    }
}

static void sci_stp_remote_device_ready_cmd_substate_enter(struct sci_base_state_machine *sm)
{
    struct isci_remote_device *idev = container_of(sm, typeof(*idev), sm);
    struct isci_host *ihost = idev->owning_port->owning_controller;

    BUG_ON(idev->working_request == NULL);

    isci_remote_device_not_ready(ihost, idev,
                     SCIC_REMOTE_DEVICE_NOT_READY_SATA_REQUEST_STARTED);
}

static void sci_stp_remote_device_ready_ncq_error_substate_enter(struct sci_base_state_machine *sm)
{
    struct isci_remote_device *idev = container_of(sm, typeof(*idev), sm);
    struct isci_host *ihost = idev->owning_port->owning_controller;

    if (idev->not_ready_reason == SCIC_REMOTE_DEVICE_NOT_READY_SATA_SDB_ERROR_FIS_RECEIVED)
        isci_remote_device_not_ready(ihost, idev,
                         idev->not_ready_reason);
}

static void sci_smp_remote_device_ready_idle_substate_enter(struct sci_base_state_machine *sm)
{
    struct isci_remote_device *idev = container_of(sm, typeof(*idev), sm);
    struct isci_host *ihost = idev->owning_port->owning_controller;

    isci_remote_device_ready(ihost, idev);
}

static void sci_smp_remote_device_ready_cmd_substate_enter(struct sci_base_state_machine *sm)
{
    struct isci_remote_device *idev = container_of(sm, typeof(*idev), sm);
    struct isci_host *ihost = idev->owning_port->owning_controller;

    BUG_ON(idev->working_request == NULL);

    isci_remote_device_not_ready(ihost, idev,
                     SCIC_REMOTE_DEVICE_NOT_READY_SMP_REQUEST_STARTED);
}

static void sci_smp_remote_device_ready_cmd_substate_exit(struct sci_base_state_machine *sm)
{
    struct isci_remote_device *idev = container_of(sm, typeof(*idev), sm);

    idev->working_request = NULL;
}

static const struct sci_base_state sci_remote_device_state_table[] = {
    [SCI_DEV_INITIAL] = {
        .enter_state = sci_remote_device_initial_state_enter,
    },
    [SCI_DEV_STOPPED] = {
        .enter_state = sci_remote_device_stopped_state_enter,
    },
    [SCI_DEV_STARTING] = {
        .enter_state = sci_remote_device_starting_state_enter,
    },
    [SCI_DEV_READY] = {
        .enter_state = sci_remote_device_ready_state_enter,
        .exit_state  = sci_remote_device_ready_state_exit
    },
    [SCI_STP_DEV_IDLE] = {
        .enter_state = sci_stp_remote_device_ready_idle_substate_enter,
    },
    [SCI_STP_DEV_CMD] = {
        .enter_state = sci_stp_remote_device_ready_cmd_substate_enter,
    },
    [SCI_STP_DEV_NCQ] = { },
    [SCI_STP_DEV_NCQ_ERROR] = {
        .enter_state = sci_stp_remote_device_ready_ncq_error_substate_enter,
    },
    [SCI_STP_DEV_ATAPI_ERROR] = { },
    [SCI_STP_DEV_AWAIT_RESET] = { },
    [SCI_SMP_DEV_IDLE] = {
        .enter_state = sci_smp_remote_device_ready_idle_substate_enter,
    },
    [SCI_SMP_DEV_CMD] = {
        .enter_state = sci_smp_remote_device_ready_cmd_substate_enter,
        .exit_state  = sci_smp_remote_device_ready_cmd_substate_exit,
    },
    [SCI_DEV_STOPPING] = { },
    [SCI_DEV_FAILED] = { },
    [SCI_DEV_RESETTING] = {
        .enter_state = sci_remote_device_resetting_state_enter,
        .exit_state  = sci_remote_device_resetting_state_exit
    },
    [SCI_DEV_FINAL] = { },
};

static void sci_remote_device_construct(struct isci_port *iport,
                  struct isci_remote_device *idev)
{
    idev->owning_port = iport;
    idev->started_request_count = 0;

    sci_init_sm(&idev->sm, sci_remote_device_state_table, SCI_DEV_INITIAL);

    sci_remote_node_context_construct(&idev->rnc,
                           SCIC_SDS_REMOTE_NODE_CONTEXT_INVALID_INDEX);
}

static enum sci_status sci_remote_device_da_construct(struct isci_port *iport,
                               struct isci_remote_device *idev)
{
    enum sci_status status;
    struct sci_port_properties properties;

    sci_remote_device_construct(iport, idev);

    sci_port_get_properties(iport, &properties);
    /* Get accurate port width from port's phy mask for a DA device. */
    idev->device_port_width = hweight32(properties.phy_mask);

    status = sci_controller_allocate_remote_node_context(iport->owning_controller,
                                 idev,
                                 &idev->rnc.remote_node_index);

    if (status != SCI_SUCCESS)
        return status;

    idev->connection_rate = sci_port_get_max_allowed_speed(iport);

    return SCI_SUCCESS;
}

static enum sci_status sci_remote_device_ea_construct(struct isci_port *iport,
                               struct isci_remote_device *idev)
{
    struct domain_device *dev = idev->domain_dev;
    enum sci_status status;

    sci_remote_device_construct(iport, idev);

    status = sci_controller_allocate_remote_node_context(iport->owning_controller,
                                  idev,
                                  &idev->rnc.remote_node_index);
    if (status != SCI_SUCCESS)
        return status;

    /* For SAS-2 the physical link rate is actually a logical link
     * rate that incorporates multiplexing.  The SCU doesn't
     * incorporate multiplexing and for the purposes of the
     * connection the logical link rate is that same as the
     * physical.  Furthermore, the SAS-2 and SAS-1.1 fields overlay
     * one another, so this code works for both situations.
     */
    idev->connection_rate = min_t(u16, sci_port_get_max_allowed_speed(iport),
                     dev->linkrate);

    /* / @todo Should I assign the port width by reading all of the phys on the port? */
    idev->device_port_width = 1;

    return SCI_SUCCESS;
}

enum sci_status sci_remote_device_resume(
    struct isci_remote_device *idev,
    scics_sds_remote_node_context_callback cb_fn,
    void *cb_p)
{
    enum sci_status status;

    status = sci_remote_node_context_resume(&idev->rnc, cb_fn, cb_p);
    if (status != SCI_SUCCESS)
        dev_dbg(scirdev_to_dev(idev), "%s: failed to resume: %d\n",
            __func__, status);
    return status;
}

static void isci_remote_device_resume_from_abort_complete(void *cbparam)
{
    struct isci_remote_device *idev = cbparam;
    struct isci_host *ihost = idev->owning_port->owning_controller;
    scics_sds_remote_node_context_callback abort_resume_cb =
        idev->abort_resume_cb;

    dev_dbg(scirdev_to_dev(idev), "%s: passing-along resume: %p\n",
        __func__, abort_resume_cb);

    if (abort_resume_cb != NULL) {
        idev->abort_resume_cb = NULL;
        abort_resume_cb(idev->abort_resume_cbparam);
    }
    clear_bit(IDEV_ABORT_PATH_RESUME_PENDING, &idev->flags);
    wake_up(&ihost->eventq);
}

static bool isci_remote_device_test_resume_done(
    struct isci_host *ihost,
    struct isci_remote_device *idev)
{
    unsigned long flags;
    bool done;

    spin_lock_irqsave(&ihost->scic_lock, flags);
    done = !test_bit(IDEV_ABORT_PATH_RESUME_PENDING, &idev->flags)
        || test_bit(IDEV_STOP_PENDING, &idev->flags)
        || sci_remote_node_context_is_being_destroyed(&idev->rnc);
    spin_unlock_irqrestore(&ihost->scic_lock, flags);

    return done;
}

void isci_remote_device_wait_for_resume_from_abort(
    struct isci_host *ihost,
    struct isci_remote_device *idev)
{
    dev_dbg(&ihost->pdev->dev, "%s: starting resume wait: %p\n",
         __func__, idev);

    #define MAX_RESUME_MSECS 10000
    if (!wait_event_timeout(ihost->eventq,
                isci_remote_device_test_resume_done(ihost, idev),
                msecs_to_jiffies(MAX_RESUME_MSECS))) {

        dev_warn(&ihost->pdev->dev, "%s: #### Timeout waiting for "
             "resume: %p\n", __func__, idev);
    }
    clear_bit(IDEV_ABORT_PATH_RESUME_PENDING, &idev->flags);

    dev_dbg(&ihost->pdev->dev, "%s: resume wait done: %p\n",
         __func__, idev);
}

enum sci_status isci_remote_device_resume_from_abort(
    struct isci_host *ihost,
    struct isci_remote_device *idev)
{
    unsigned long flags;
    enum sci_status status = SCI_SUCCESS;
    int destroyed;

    spin_lock_irqsave(&ihost->scic_lock, flags);
    /* Preserve any current resume callbacks, for instance from other
     * resumptions.
     */
    idev->abort_resume_cb = idev->rnc.user_callback;
    idev->abort_resume_cbparam = idev->rnc.user_cookie;
    set_bit(IDEV_ABORT_PATH_RESUME_PENDING, &idev->flags);
    clear_bit(IDEV_ABORT_PATH_ACTIVE, &idev->flags);
    destroyed = sci_remote_node_context_is_being_destroyed(&idev->rnc);
    if (!destroyed)
        status = sci_remote_device_resume(
            idev, isci_remote_device_resume_from_abort_complete,
            idev);
    spin_unlock_irqrestore(&ihost->scic_lock, flags);
    if (!destroyed && (status == SCI_SUCCESS))
        isci_remote_device_wait_for_resume_from_abort(ihost, idev);
    else
        clear_bit(IDEV_ABORT_PATH_RESUME_PENDING, &idev->flags);

    return status;
}

static enum sci_status sci_remote_device_start(struct isci_remote_device *idev,
                           u32 timeout)
{
    struct sci_base_state_machine *sm = &idev->sm;
    enum sci_remote_device_states state = sm->current_state_id;
    enum sci_status status;

    if (state != SCI_DEV_STOPPED) {
        dev_warn(scirdev_to_dev(idev), "%s: in wrong state: %s\n",
             __func__, dev_state_name(state));
        return SCI_FAILURE_INVALID_STATE;
    }

    status = sci_remote_device_resume(idev, remote_device_resume_done,
                      idev);
    if (status != SCI_SUCCESS)
        return status;

    sci_change_state(sm, SCI_DEV_STARTING);

    return SCI_SUCCESS;
}

static enum sci_status isci_remote_device_construct(struct isci_port *iport,
                            struct isci_remote_device *idev)
{
    struct isci_host *ihost = iport->isci_host;
    struct domain_device *dev = idev->domain_dev;
    enum sci_status status;

    if (dev->parent && dev_is_expander(dev->parent))
        status = sci_remote_device_ea_construct(iport, idev);
    else
        status = sci_remote_device_da_construct(iport, idev);

    if (status != SCI_SUCCESS) {
        dev_dbg(&ihost->pdev->dev, "%s: construct failed: %d\n",
            __func__, status);

        return status;
    }

    /* start the device. */
    status = sci_remote_device_start(idev, ISCI_REMOTE_DEVICE_START_TIMEOUT);

    if (status != SCI_SUCCESS)
        dev_warn(&ihost->pdev->dev, "remote device start failed: %d\n",
             status);

    return status;
}

static struct isci_remote_device *
isci_remote_device_alloc(struct isci_host *ihost, struct isci_port *iport)
{
    struct isci_remote_device *idev;
    int i;

    for (i = 0; i < SCI_MAX_REMOTE_DEVICES; i++) {
        idev = &ihost->devices[i];
        if (!test_and_set_bit(IDEV_ALLOCATED, &idev->flags))
            break;
    }

    if (i >= SCI_MAX_REMOTE_DEVICES) {
        dev_warn(&ihost->pdev->dev, "%s: failed\n", __func__);
        return NULL;
    }
    if (WARN_ONCE(!list_empty(&idev->node), "found non-idle remote device\n"))
        return NULL;

    return idev;
}

void isci_remote_device_release(struct kref *kref)
{
    struct isci_remote_device *idev = container_of(kref, typeof(*idev), kref);
    struct isci_host *ihost = idev->isci_port->isci_host;

    idev->domain_dev = NULL;
    idev->isci_port = NULL;
    clear_bit(IDEV_START_PENDING, &idev->flags);
    clear_bit(IDEV_STOP_PENDING, &idev->flags);
    clear_bit(IDEV_IO_READY, &idev->flags);
    clear_bit(IDEV_GONE, &idev->flags);
    smp_mb__before_clear_bit();
    clear_bit(IDEV_ALLOCATED, &idev->flags);
    wake_up(&ihost->eventq);
}

enum sci_status isci_remote_device_stop(struct isci_host *ihost, struct isci_remote_device *idev)
{
    enum sci_status status;
    unsigned long flags;

    dev_dbg(&ihost->pdev->dev,
        "%s: isci_device = %p\n", __func__, idev);

    spin_lock_irqsave(&ihost->scic_lock, flags);
    idev->domain_dev->lldd_dev = NULL; /* disable new lookups */
    set_bit(IDEV_GONE, &idev->flags);

    set_bit(IDEV_STOP_PENDING, &idev->flags);
    status = sci_remote_device_stop(idev, 50);
    spin_unlock_irqrestore(&ihost->scic_lock, flags);

    /* Wait for the stop complete callback. */
    if (WARN_ONCE(status != SCI_SUCCESS, "failed to stop device\n"))
        /* nothing to wait for */;
    else
        wait_for_device_stop(ihost, idev);

    dev_dbg(&ihost->pdev->dev,
        "%s: isci_device = %p, waiting done.\n", __func__, idev);

    return status;
}

void isci_remote_device_gone(struct domain_device *dev)
{
    struct isci_host *ihost = dev_to_ihost(dev);
    struct isci_remote_device *idev = dev->lldd_dev;

    dev_dbg(&ihost->pdev->dev,
        "%s: domain_device = %p, isci_device = %p, isci_port = %p\n",
        __func__, dev, idev, idev->isci_port);

    isci_remote_device_stop(ihost, idev);
}


int isci_remote_device_found(struct domain_device *dev)
{
    struct isci_host *isci_host = dev_to_ihost(dev);
    struct isci_port *isci_port = dev->port->lldd_port;
    struct isci_remote_device *isci_device;
    enum sci_status status;

    dev_dbg(&isci_host->pdev->dev,
        "%s: domain_device = %p\n", __func__, dev);

    if (!isci_port)
        return -ENODEV;

    isci_device = isci_remote_device_alloc(isci_host, isci_port);
    if (!isci_device)
        return -ENODEV;

    kref_init(&isci_device->kref);
    INIT_LIST_HEAD(&isci_device->node);

    spin_lock_irq(&isci_host->scic_lock);
    isci_device->domain_dev = dev;
    isci_device->isci_port = isci_port;
    list_add_tail(&isci_device->node, &isci_port->remote_dev_list);

    set_bit(IDEV_START_PENDING, &isci_device->flags);
    status = isci_remote_device_construct(isci_port, isci_device);

    dev_dbg(&isci_host->pdev->dev,
        "%s: isci_device = %p\n",
        __func__, isci_device);

    if (status == SCI_SUCCESS) {
        /* device came up, advertise it to the world */
        dev->lldd_dev = isci_device;
    } else
        isci_put_device(isci_device);
    spin_unlock_irq(&isci_host->scic_lock);

    /* wait for the device ready callback. */
    wait_for_device_start(isci_host, isci_device);

    return status == SCI_SUCCESS ? 0 : -ENODEV;
}

enum sci_status isci_remote_device_suspend_terminate(
    struct isci_host *ihost,
    struct isci_remote_device *idev,
    struct isci_request *ireq)
{
    unsigned long flags;
    enum sci_status status;

    /* Put the device into suspension. */
    spin_lock_irqsave(&ihost->scic_lock, flags);
    set_bit(IDEV_ABORT_PATH_ACTIVE, &idev->flags);
    sci_remote_device_suspend(idev, SCI_SW_SUSPEND_LINKHANG_DETECT);
    spin_unlock_irqrestore(&ihost->scic_lock, flags);

    /* Terminate and wait for the completions. */
    status = isci_remote_device_terminate_requests(ihost, idev, ireq);
    if (status != SCI_SUCCESS)
        dev_dbg(&ihost->pdev->dev,
            "%s: isci_remote_device_terminate_requests(%p) "
                "returned %d!\n",
            __func__, idev, status);

    /* NOTE: RNC resumption is left to the caller! */
    return status;
}

int isci_remote_device_is_safe_to_abort(
    struct isci_remote_device *idev)
{
    return sci_remote_node_context_is_safe_to_abort(&idev->rnc);
}

enum sci_status sci_remote_device_abort_requests_pending_abort(
    struct isci_remote_device *idev)
{
    return sci_remote_device_terminate_reqs_checkabort(idev, 1);
}

enum sci_status isci_remote_device_reset_complete(
    struct isci_host *ihost,
    struct isci_remote_device *idev)
{
    unsigned long flags;
    enum sci_status status;

    spin_lock_irqsave(&ihost->scic_lock, flags);
    status = sci_remote_device_reset_complete(idev);
    spin_unlock_irqrestore(&ihost->scic_lock, flags);

    return status;
}

void isci_dev_set_hang_detection_timeout(
    struct isci_remote_device *idev,
    u32 timeout)
{
    if (dev_is_sata(idev->domain_dev)) {
        if (timeout) {
            if (test_and_set_bit(IDEV_RNC_LLHANG_ENABLED,
                         &idev->flags))
                return;  /* Already enabled. */
        } else if (!test_and_clear_bit(IDEV_RNC_LLHANG_ENABLED,
                           &idev->flags))
            return;  /* Not enabled. */

        sci_port_set_hang_detection_timeout(idev->owning_port,
                            timeout);
    }
}