Merge remote-tracking branch 's5p/for-next'

[linux-2.6/next.git] / drivers / scsi / isci / task.c

/*
 * 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 <linux/completion.h>
#include <linux/irqflags.h>
#include "sas.h"
#include <scsi/libsas.h>
#include "remote_device.h"
#include "remote_node_context.h"
#include "isci.h"
#include "request.h"
#include "task.h"
#include "host.h"

/**
* isci_task_refuse() - complete the request to the upper layer driver in
*     the case where an I/O needs to be completed back in the submit path.
* @ihost: host on which the the request was queued
* @task: request to complete
* @response: response code for the completed task.
* @status: status code for the completed task.
*
*/
static void isci_task_refuse(struct isci_host *ihost, struct sas_task *task,
                             enum service_response response,
                             enum exec_status status)

{
        enum isci_completion_selection disposition;

        disposition = isci_perform_normal_io_completion;
        disposition = isci_task_set_completion_status(task, response, status,
                                                      disposition);

        /* Tasks aborted specifically by a call to the lldd_abort_task
         * function should not be completed to the host in the regular path.
         */
        switch (disposition) {
        case isci_perform_normal_io_completion:
                /* Normal notification (task_done) */
                dev_dbg(&ihost->pdev->dev,
                        "%s: Normal - task = %p, response=%d, "
                        "status=%d\n",
                        __func__, task, response, status);

                task->lldd_task = NULL;

                isci_execpath_callback(ihost, task, task->task_done);
                break;

        case isci_perform_aborted_io_completion:
                /*
                 * No notification because this request is already in the
                 * abort path.
                 */
                dev_dbg(&ihost->pdev->dev,
                        "%s: Aborted - task = %p, response=%d, "
                        "status=%d\n",
                        __func__, task, response, status);
                break;

        case isci_perform_error_io_completion:
                /* Use sas_task_abort */
                dev_dbg(&ihost->pdev->dev,
                        "%s: Error - task = %p, response=%d, "
                        "status=%d\n",
                        __func__, task, response, status);

                isci_execpath_callback(ihost, task, sas_task_abort);
                break;

        default:
                dev_dbg(&ihost->pdev->dev,
                        "%s: isci task notification default case!",
                        __func__);
                sas_task_abort(task);
                break;
        }
}

#define for_each_sas_task(num, task) \
        for (; num > 0; num--,\
             task = list_entry(task->list.next, struct sas_task, list))


static inline int isci_device_io_ready(struct isci_remote_device *idev,
                                       struct sas_task *task)
{
        return idev ? test_bit(IDEV_IO_READY, &idev->flags) ||
                      (test_bit(IDEV_IO_NCQERROR, &idev->flags) &&
                       isci_task_is_ncq_recovery(task))
                    : 0;
}
/**
 * isci_task_execute_task() - This function is one of the SAS Domain Template
 *    functions. This function is called by libsas to send a task down to
 *    hardware.
 * @task: This parameter specifies the SAS task to send.
 * @num: This parameter specifies the number of tasks to queue.
 * @gfp_flags: This parameter specifies the context of this call.
 *
 * status, zero indicates success.
 */
int isci_task_execute_task(struct sas_task *task, int num, gfp_t gfp_flags)
{
        struct isci_host *ihost = dev_to_ihost(task->dev);
        struct isci_remote_device *idev;
        unsigned long flags;
        bool io_ready;
        u16 tag;

        dev_dbg(&ihost->pdev->dev, "%s: num=%d\n", __func__, num);

        for_each_sas_task(num, task) {
                enum sci_status status = SCI_FAILURE;

                spin_lock_irqsave(&ihost->scic_lock, flags);
                idev = isci_lookup_device(task->dev);
                io_ready = isci_device_io_ready(idev, task);
                tag = isci_alloc_tag(ihost);
                spin_unlock_irqrestore(&ihost->scic_lock, flags);

                dev_dbg(&ihost->pdev->dev,
                        "task: %p, num: %d dev: %p idev: %p:%#lx cmd = %p\n",
                        task, num, task->dev, idev, idev ? idev->flags : 0,
                        task->uldd_task);

                if (!idev) {
                        isci_task_refuse(ihost, task, SAS_TASK_UNDELIVERED,
                                         SAS_DEVICE_UNKNOWN);
                } else if (!io_ready || tag == SCI_CONTROLLER_INVALID_IO_TAG) {
                        /* Indicate QUEUE_FULL so that the scsi midlayer
                         * retries.
                          */
                        isci_task_refuse(ihost, task, SAS_TASK_COMPLETE,
                                         SAS_QUEUE_FULL);
                } else {
                        /* There is a device and it's ready for I/O. */
                        spin_lock_irqsave(&task->task_state_lock, flags);

                        if (task->task_state_flags & SAS_TASK_STATE_ABORTED) {
                                /* The I/O was aborted. */
                                spin_unlock_irqrestore(&task->task_state_lock,
                                                       flags);

                                isci_task_refuse(ihost, task,
                                                 SAS_TASK_UNDELIVERED,
                                                 SAM_STAT_TASK_ABORTED);
                        } else {
                                task->task_state_flags |= SAS_TASK_AT_INITIATOR;
                                spin_unlock_irqrestore(&task->task_state_lock, flags);

                                /* build and send the request. */
                                status = isci_request_execute(ihost, idev, task, tag);

                                if (status != SCI_SUCCESS) {

                                        spin_lock_irqsave(&task->task_state_lock, flags);
                                        /* Did not really start this command. */
                                        task->task_state_flags &= ~SAS_TASK_AT_INITIATOR;
                                        spin_unlock_irqrestore(&task->task_state_lock, flags);

                                        /* Indicate QUEUE_FULL so that the scsi
                                        * midlayer retries. if the request
                                        * failed for remote device reasons,
                                        * it gets returned as
                                        * SAS_TASK_UNDELIVERED next time
                                        * through.
                                        */
                                        isci_task_refuse(ihost, task,
                                                         SAS_TASK_COMPLETE,
                                                         SAS_QUEUE_FULL);
                                }
                        }
                }
                if (status != SCI_SUCCESS && tag != SCI_CONTROLLER_INVALID_IO_TAG) {
                        spin_lock_irqsave(&ihost->scic_lock, flags);
                        /* command never hit the device, so just free
                         * the tci and skip the sequence increment
                         */
                        isci_tci_free(ihost, ISCI_TAG_TCI(tag));
                        spin_unlock_irqrestore(&ihost->scic_lock, flags);
                }
                isci_put_device(idev);
        }
        return 0;
}

static enum sci_status isci_sata_management_task_request_build(struct isci_request *ireq)
{
        struct isci_tmf *isci_tmf;
        enum sci_status status;

        if (tmf_task != ireq->ttype)
                return SCI_FAILURE;

        isci_tmf = isci_request_access_tmf(ireq);

        switch (isci_tmf->tmf_code) {

        case isci_tmf_sata_srst_high:
        case isci_tmf_sata_srst_low: {
                struct host_to_dev_fis *fis = &ireq->stp.cmd;

                memset(fis, 0, sizeof(*fis));

                fis->fis_type  =  0x27;
                fis->flags     &= ~0x80;
                fis->flags     &= 0xF0;
                if (isci_tmf->tmf_code == isci_tmf_sata_srst_high)
                        fis->control |= ATA_SRST;
                else
                        fis->control &= ~ATA_SRST;
                break;
        }
        /* other management commnd go here... */
        default:
                return SCI_FAILURE;
        }

        /* core builds the protocol specific request
         *  based on the h2d fis.
         */
        status = sci_task_request_construct_sata(ireq);

        return status;
}

static struct isci_request *isci_task_request_build(struct isci_host *ihost,
                                                    struct isci_remote_device *idev,
                                                    u16 tag, struct isci_tmf *isci_tmf)
{
        enum sci_status status = SCI_FAILURE;
        struct isci_request *ireq = NULL;
        struct domain_device *dev;

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

        dev = idev->domain_dev;

        /* do common allocation and init of request object. */
        ireq = isci_tmf_request_from_tag(ihost, isci_tmf, tag);
        if (!ireq)
                return NULL;

        /* let the core do it's construct. */
        status = sci_task_request_construct(ihost, idev, tag,
                                             ireq);

        if (status != SCI_SUCCESS) {
                dev_warn(&ihost->pdev->dev,
                         "%s: sci_task_request_construct failed - "
                         "status = 0x%x\n",
                         __func__,
                         status);
                return NULL;
        }

        /* XXX convert to get this from task->tproto like other drivers */
        if (dev->dev_type == SAS_END_DEV) {
                isci_tmf->proto = SAS_PROTOCOL_SSP;
                status = sci_task_request_construct_ssp(ireq);
                if (status != SCI_SUCCESS)
                        return NULL;
        }

        if (dev->dev_type == SATA_DEV || (dev->tproto & SAS_PROTOCOL_STP)) {
                isci_tmf->proto = SAS_PROTOCOL_SATA;
                status = isci_sata_management_task_request_build(ireq);

                if (status != SCI_SUCCESS)
                        return NULL;
        }
        return ireq;
}

static int isci_task_execute_tmf(struct isci_host *ihost,
                                 struct isci_remote_device *idev,
                                 struct isci_tmf *tmf, unsigned long timeout_ms)
{
        DECLARE_COMPLETION_ONSTACK(completion);
        enum sci_task_status status = SCI_TASK_FAILURE;
        struct isci_request *ireq;
        int ret = TMF_RESP_FUNC_FAILED;
        unsigned long flags;
        unsigned long timeleft;
        u16 tag;

        spin_lock_irqsave(&ihost->scic_lock, flags);
        tag = isci_alloc_tag(ihost);
        spin_unlock_irqrestore(&ihost->scic_lock, flags);

        if (tag == SCI_CONTROLLER_INVALID_IO_TAG)
                return ret;

        /* sanity check, return TMF_RESP_FUNC_FAILED
         * if the device is not there and ready.
         */
        if (!idev ||
            (!test_bit(IDEV_IO_READY, &idev->flags) &&
             !test_bit(IDEV_IO_NCQERROR, &idev->flags))) {
                dev_dbg(&ihost->pdev->dev,
                        "%s: idev = %p not ready (%#lx)\n",
                        __func__,
                        idev, idev ? idev->flags : 0);
                goto err_tci;
        } else
                dev_dbg(&ihost->pdev->dev,
                        "%s: idev = %p\n",
                        __func__, idev);

        /* Assign the pointer to the TMF's completion kernel wait structure. */
        tmf->complete = &completion;

        ireq = isci_task_request_build(ihost, idev, tag, tmf);
        if (!ireq)
                goto err_tci;

        spin_lock_irqsave(&ihost->scic_lock, flags);

        /* start the TMF io. */
        status = sci_controller_start_task(ihost, idev, ireq);

        if (status != SCI_TASK_SUCCESS) {
                dev_dbg(&ihost->pdev->dev,
                         "%s: start_io failed - status = 0x%x, request = %p\n",
                         __func__,
                         status,
                         ireq);
                spin_unlock_irqrestore(&ihost->scic_lock, flags);
                goto err_tci;
        }

        if (tmf->cb_state_func != NULL)
                tmf->cb_state_func(isci_tmf_started, tmf, tmf->cb_data);

        isci_request_change_state(ireq, started);

        /* add the request to the remote device request list. */
        list_add(&ireq->dev_node, &idev->reqs_in_process);

        spin_unlock_irqrestore(&ihost->scic_lock, flags);

        /* Wait for the TMF to complete, or a timeout. */
        timeleft = wait_for_completion_timeout(&completion,
                                               msecs_to_jiffies(timeout_ms));

        if (timeleft == 0) {
                spin_lock_irqsave(&ihost->scic_lock, flags);

                if (tmf->cb_state_func != NULL)
                        tmf->cb_state_func(isci_tmf_timed_out, tmf, tmf->cb_data);

                sci_controller_terminate_request(ihost,
                                                  idev,
                                                  ireq);

                spin_unlock_irqrestore(&ihost->scic_lock, flags);

                wait_for_completion(tmf->complete);
        }

        isci_print_tmf(tmf);

        if (tmf->status == SCI_SUCCESS)
                ret =  TMF_RESP_FUNC_COMPLETE;
        else if (tmf->status == SCI_FAILURE_IO_RESPONSE_VALID) {
                dev_dbg(&ihost->pdev->dev,
                        "%s: tmf.status == "
                        "SCI_FAILURE_IO_RESPONSE_VALID\n",
                        __func__);
                ret =  TMF_RESP_FUNC_COMPLETE;
        }
        /* Else - leave the default "failed" status alone. */

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

        return ret;

 err_tci:
        spin_lock_irqsave(&ihost->scic_lock, flags);
        isci_tci_free(ihost, ISCI_TAG_TCI(tag));
        spin_unlock_irqrestore(&ihost->scic_lock, flags);

        return ret;
}

static void isci_task_build_tmf(struct isci_tmf *tmf,
                                enum isci_tmf_function_codes code,
                                void (*tmf_sent_cb)(enum isci_tmf_cb_state,
                                                    struct isci_tmf *,
                                                    void *),
                                void *cb_data)
{
        memset(tmf, 0, sizeof(*tmf));

        tmf->tmf_code      = code;
        tmf->cb_state_func = tmf_sent_cb;
        tmf->cb_data       = cb_data;
}

static void isci_task_build_abort_task_tmf(struct isci_tmf *tmf,
                                           enum isci_tmf_function_codes code,
                                           void (*tmf_sent_cb)(enum isci_tmf_cb_state,
                                                               struct isci_tmf *,
                                                               void *),
                                           struct isci_request *old_request)
{
        isci_task_build_tmf(tmf, code, tmf_sent_cb, old_request);
        tmf->io_tag = old_request->io_tag;
}

/**
 * isci_task_validate_request_to_abort() - This function checks the given I/O
 *    against the "started" state.  If the request is still "started", it's
 *    state is changed to aborted. NOTE: isci_host->scic_lock MUST BE HELD
 *    BEFORE CALLING THIS FUNCTION.
 * @isci_request: This parameter specifies the request object to control.
 * @isci_host: This parameter specifies the ISCI host object
 * @isci_device: This is the device to which the request is pending.
 * @aborted_io_completion: This is a completion structure that will be added to
 *    the request in case it is changed to aborting; this completion is
 *    triggered when the request is fully completed.
 *
 * Either "started" on successful change of the task status to "aborted", or
 * "unallocated" if the task cannot be controlled.
 */
static enum isci_request_status isci_task_validate_request_to_abort(
        struct isci_request *isci_request,
        struct isci_host *isci_host,
        struct isci_remote_device *isci_device,
        struct completion *aborted_io_completion)
{
        enum isci_request_status old_state = unallocated;

        /* Only abort the task if it's in the
         *  device's request_in_process list
         */
        if (isci_request && !list_empty(&isci_request->dev_node)) {
                old_state = isci_request_change_started_to_aborted(
                        isci_request, aborted_io_completion);

        }

        return old_state;
}

/**
* isci_request_cleanup_completed_loiterer() - This function will take care of
*    the final cleanup on any request which has been explicitly terminated.
* @isci_host: This parameter specifies the ISCI host object
* @isci_device: This is the device to which the request is pending.
* @isci_request: This parameter specifies the terminated request object.
* @task: This parameter is the libsas I/O request.
*/
static void isci_request_cleanup_completed_loiterer(
        struct isci_host          *isci_host,
        struct isci_remote_device *isci_device,
        struct isci_request       *isci_request,
        struct sas_task           *task)
{
        unsigned long flags;

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

        if (task != NULL) {

                spin_lock_irqsave(&task->task_state_lock, flags);
                task->lldd_task = NULL;

                task->task_state_flags &= ~SAS_TASK_NEED_DEV_RESET;

                isci_set_task_doneflags(task);

                /* If this task is not in the abort path, call task_done. */
                if (!(task->task_state_flags & SAS_TASK_STATE_ABORTED)) {

                        spin_unlock_irqrestore(&task->task_state_lock, flags);
                        task->task_done(task);
                } else
                        spin_unlock_irqrestore(&task->task_state_lock, flags);
        }

        if (isci_request != NULL) {
                spin_lock_irqsave(&isci_host->scic_lock, flags);
                list_del_init(&isci_request->dev_node);
                spin_unlock_irqrestore(&isci_host->scic_lock, flags);
        }
}

/**
 * isci_terminate_request_core() - This function will terminate the given
 *    request, and wait for it to complete.  This function must only be called
 *    from a thread that can wait.  Note that the request is terminated and
 *    completed (back to the host, if started there).
 * @ihost: This SCU.
 * @idev: The target.
 * @isci_request: The I/O request to be terminated.
 *
 */
static void isci_terminate_request_core(struct isci_host *ihost,
                                        struct isci_remote_device *idev,
                                        struct isci_request *isci_request)
{
        enum sci_status status      = SCI_SUCCESS;
        bool was_terminated         = false;
        bool needs_cleanup_handling = false;
        enum isci_request_status request_status;
        unsigned long     flags;
        unsigned long     termination_completed = 1;
        struct completion *io_request_completion;
        struct sas_task   *task;

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

        spin_lock_irqsave(&ihost->scic_lock, flags);

        io_request_completion = isci_request->io_request_completion;

        task = (isci_request->ttype == io_task)
                ? isci_request_access_task(isci_request)
                : NULL;

        /* Note that we are not going to control
         * the target to abort the request.
         */
        set_bit(IREQ_COMPLETE_IN_TARGET, &isci_request->flags);

        /* Make sure the request wasn't just sitting around signalling
         * device condition (if the request handle is NULL, then the
         * request completed but needed additional handling here).
         */
        if (!test_bit(IREQ_TERMINATED, &isci_request->flags)) {
                was_terminated = true;
                needs_cleanup_handling = true;
                status = sci_controller_terminate_request(ihost,
                                                           idev,
                                                           isci_request);
        }
        spin_unlock_irqrestore(&ihost->scic_lock, flags);

        /*
         * The only time the request to terminate will
         * fail is when the io request is completed and
         * being aborted.
         */
        if (status != SCI_SUCCESS) {
                dev_dbg(&ihost->pdev->dev,
                        "%s: sci_controller_terminate_request"
                        " returned = 0x%x\n",
                        __func__, status);

                isci_request->io_request_completion = NULL;

        } else {
                if (was_terminated) {
                        dev_dbg(&ihost->pdev->dev,
                                "%s: before completion wait (%p/%p)\n",
                                __func__, isci_request, io_request_completion);

                        /* Wait here for the request to complete. */
                        #define TERMINATION_TIMEOUT_MSEC 500
                        termination_completed
                                = wait_for_completion_timeout(
                                   io_request_completion,
                                   msecs_to_jiffies(TERMINATION_TIMEOUT_MSEC));

                        if (!termination_completed) {

                                /* The request to terminate has timed out.  */
                                spin_lock_irqsave(&ihost->scic_lock,
                                                  flags);

                                /* Check for state changes. */
                                if (!test_bit(IREQ_TERMINATED, &isci_request->flags)) {

                                        /* The best we can do is to have the
                                         * request die a silent death if it
                                         * ever really completes.
                                         *
                                         * Set the request state to "dead",
                                         * and clear the task pointer so that
                                         * an actual completion event callback
                                         * doesn't do anything.
                                         */
                                        isci_request->status = dead;
                                        isci_request->io_request_completion
                                                = NULL;

                                        if (isci_request->ttype == io_task) {

                                                /* Break links with the
                                                * sas_task.
                                                */
                                                isci_request->ttype_ptr.io_task_ptr
                                                        = NULL;
                                        }
                                } else
                                        termination_completed = 1;

                                spin_unlock_irqrestore(&ihost->scic_lock,
                                                       flags);

                                if (!termination_completed) {

                                        dev_dbg(&ihost->pdev->dev,
                                                "%s: *** Timeout waiting for "
                                                "termination(%p/%p)\n",
                                                __func__, io_request_completion,
                                                isci_request);

                                        /* The request can no longer be referenced
                                         * safely since it may go away if the
                                         * termination every really does complete.
                                         */
                                        isci_request = NULL;
                                }
                        }
                        if (termination_completed)
                                dev_dbg(&ihost->pdev->dev,
                                        "%s: after completion wait (%p/%p)\n",
                                        __func__, isci_request, io_request_completion);
                }

                if (termination_completed) {

                        isci_request->io_request_completion = NULL;

                        /* Peek at the status of the request.  This will tell
                         * us if there was special handling on the request such that it
                         * needs to be detached and freed here.
                         */
                        spin_lock_irqsave(&isci_request->state_lock, flags);
                        request_status = isci_request->status;

                        if ((isci_request->ttype == io_task) /* TMFs are in their own thread */
                            && ((request_status == aborted)
                                || (request_status == aborting)
                                || (request_status == terminating)
                                || (request_status == completed)
                                || (request_status == dead)
                                )
                            ) {

                                /* The completion routine won't free a request in
                                 * the aborted/aborting/etc. states, so we do
                                 * it here.
                                 */
                                needs_cleanup_handling = true;
                        }
                        spin_unlock_irqrestore(&isci_request->state_lock, flags);

                }
                if (needs_cleanup_handling)
                        isci_request_cleanup_completed_loiterer(
                                ihost, idev, isci_request, task);
        }
}

/**
 * isci_terminate_pending_requests() - This function will change the all of the
 *    requests on the given device's state to "aborting", will terminate the
 *    requests, and wait for them to complete.  This function must only be
 *    called from a thread that can wait.  Note that the requests are all
 *    terminated and completed (back to the host, if started there).
 * @isci_host: This parameter specifies SCU.
 * @idev: This parameter specifies the target.
 *
 */
void isci_terminate_pending_requests(struct isci_host *ihost,
                                     struct isci_remote_device *idev)
{
        struct completion request_completion;
        enum isci_request_status old_state;
        unsigned long flags;
        LIST_HEAD(list);

        spin_lock_irqsave(&ihost->scic_lock, flags);
        list_splice_init(&idev->reqs_in_process, &list);

        /* assumes that isci_terminate_request_core deletes from the list */
        while (!list_empty(&list)) {
                struct isci_request *ireq = list_entry(list.next, typeof(*ireq), dev_node);

                /* Change state to "terminating" if it is currently
                 * "started".
                 */
                old_state = isci_request_change_started_to_newstate(ireq,
                                                                    &request_completion,
                                                                    terminating);
                switch (old_state) {
                case started:
                case completed:
                case aborting:
                        break;
                default:
                        /* termination in progress, or otherwise dispositioned.
                         * We know the request was on 'list' so should be safe
                         * to move it back to reqs_in_process
                         */
                        list_move(&ireq->dev_node, &idev->reqs_in_process);
                        ireq = NULL;
                        break;
                }

                if (!ireq)
                        continue;
                spin_unlock_irqrestore(&ihost->scic_lock, flags);

                init_completion(&request_completion);

                dev_dbg(&ihost->pdev->dev,
                         "%s: idev=%p request=%p; task=%p old_state=%d\n",
                         __func__, idev, ireq,
                        ireq->ttype == io_task ? isci_request_access_task(ireq) : NULL,
                        old_state);

                /* If the old_state is started:
                 * This request was not already being aborted. If it had been,
                 * then the aborting I/O (ie. the TMF request) would not be in
                 * the aborting state, and thus would be terminated here.  Note
                 * that since the TMF completion's call to the kernel function
                 * "complete()" does not happen until the pending I/O request
                 * terminate fully completes, we do not have to implement a
                 * special wait here for already aborting requests - the
                 * termination of the TMF request will force the request
                 * to finish it's already started terminate.
                 *
                 * If old_state == completed:
                 * This request completed from the SCU hardware perspective
                 * and now just needs cleaning up in terms of freeing the
                 * request and potentially calling up to libsas.
                 *
                 * If old_state == aborting:
                 * This request has already gone through a TMF timeout, but may
                 * not have been terminated; needs cleaning up at least.
                 */
                isci_terminate_request_core(ihost, idev, ireq);
                spin_lock_irqsave(&ihost->scic_lock, flags);
        }
        spin_unlock_irqrestore(&ihost->scic_lock, flags);
}

/**
 * isci_task_send_lu_reset_sas() - This function is called by of the SAS Domain
 *    Template functions.
 * @lun: This parameter specifies the lun to be reset.
 *
 * status, zero indicates success.
 */
static int isci_task_send_lu_reset_sas(
        struct isci_host *isci_host,
        struct isci_remote_device *isci_device,
        u8 *lun)
{
        struct isci_tmf tmf;
        int ret = TMF_RESP_FUNC_FAILED;

        dev_dbg(&isci_host->pdev->dev,
                "%s: isci_host = %p, isci_device = %p\n",
                __func__, isci_host, isci_device);
        /* Send the LUN reset to the target.  By the time the call returns,
         * the TMF has fully exected in the target (in which case the return
         * value is "TMF_RESP_FUNC_COMPLETE", or the request timed-out (or
         * was otherwise unable to be executed ("TMF_RESP_FUNC_FAILED").
         */
        isci_task_build_tmf(&tmf, isci_tmf_ssp_lun_reset, NULL, NULL);

        #define ISCI_LU_RESET_TIMEOUT_MS 2000 /* 2 second timeout. */
        ret = isci_task_execute_tmf(isci_host, isci_device, &tmf, ISCI_LU_RESET_TIMEOUT_MS);

        if (ret == TMF_RESP_FUNC_COMPLETE)
                dev_dbg(&isci_host->pdev->dev,
                        "%s: %p: TMF_LU_RESET passed\n",
                        __func__, isci_device);
        else
                dev_dbg(&isci_host->pdev->dev,
                        "%s: %p: TMF_LU_RESET failed (%x)\n",
                        __func__, isci_device, ret);

        return ret;
}

static int isci_task_send_lu_reset_sata(struct isci_host *ihost,
                                 struct isci_remote_device *idev, u8 *lun)
{
        int ret = TMF_RESP_FUNC_FAILED;
        struct isci_tmf tmf;

        /* Send the soft reset to the target */
        #define ISCI_SRST_TIMEOUT_MS 25000 /* 25 second timeout. */
        isci_task_build_tmf(&tmf, isci_tmf_sata_srst_high, NULL, NULL);

        ret = isci_task_execute_tmf(ihost, idev, &tmf, ISCI_SRST_TIMEOUT_MS);

        if (ret != TMF_RESP_FUNC_COMPLETE) {
                dev_dbg(&ihost->pdev->dev,
                         "%s: Assert SRST failed (%p) = %x",
                         __func__, idev, ret);

                /* Return the failure so that the LUN reset is escalated
                 * to a target reset.
                 */
        }
        return ret;
}

/**
 * isci_task_lu_reset() - This function is one of the SAS Domain Template
 *    functions. This is one of the Task Management functoins called by libsas,
 *    to reset the given lun. Note the assumption that while this call is
 *    executing, no I/O will be sent by the host to the device.
 * @lun: This parameter specifies the lun to be reset.
 *
 * status, zero indicates success.
 */
int isci_task_lu_reset(struct domain_device *domain_device, u8 *lun)
{
        struct isci_host *isci_host = dev_to_ihost(domain_device);
        struct isci_remote_device *isci_device;
        unsigned long flags;
        int ret;

        spin_lock_irqsave(&isci_host->scic_lock, flags);
        isci_device = isci_lookup_device(domain_device);
        spin_unlock_irqrestore(&isci_host->scic_lock, flags);

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

        if (isci_device)
                set_bit(IDEV_EH, &isci_device->flags);

        /* If there is a device reset pending on any request in the
         * device's list, fail this LUN reset request in order to
         * escalate to the device reset.
         */
        if (!isci_device ||
            isci_device_is_reset_pending(isci_host, isci_device)) {
                dev_dbg(&isci_host->pdev->dev,
                         "%s: No dev (%p), or "
                         "RESET PENDING: domain_device=%p\n",
                         __func__, isci_device, domain_device);
                ret = TMF_RESP_FUNC_FAILED;
                goto out;
        }

        /* Send the task management part of the reset. */
        if (sas_protocol_ata(domain_device->tproto)) {
                ret = isci_task_send_lu_reset_sata(isci_host, isci_device, lun);
        } else
                ret = isci_task_send_lu_reset_sas(isci_host, isci_device, lun);

        /* If the LUN reset worked, all the I/O can now be terminated. */
        if (ret == TMF_RESP_FUNC_COMPLETE)
                /* Terminate all I/O now. */
                isci_terminate_pending_requests(isci_host,
                                                isci_device);

 out:
        isci_put_device(isci_device);
        return ret;
}


/*       int (*lldd_clear_nexus_port)(struct asd_sas_port *); */
int isci_task_clear_nexus_port(struct asd_sas_port *port)
{
        return TMF_RESP_FUNC_FAILED;
}



int isci_task_clear_nexus_ha(struct sas_ha_struct *ha)
{
        return TMF_RESP_FUNC_FAILED;
}

/* Task Management Functions. Must be called from process context.       */

/**
 * isci_abort_task_process_cb() - This is a helper function for the abort task
 *    TMF command.  It manages the request state with respect to the successful
 *    transmission / completion of the abort task request.
 * @cb_state: This parameter specifies when this function was called - after
 *    the TMF request has been started and after it has timed-out.
 * @tmf: This parameter specifies the TMF in progress.
 *
 *
 */
static void isci_abort_task_process_cb(
        enum isci_tmf_cb_state cb_state,
        struct isci_tmf *tmf,
        void *cb_data)
{
        struct isci_request *old_request;

        old_request = (struct isci_request *)cb_data;

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

        switch (cb_state) {

        case isci_tmf_started:
                /* The TMF has been started.  Nothing to do here, since the
                 * request state was already set to "aborted" by the abort
                 * task function.
                 */
                if ((old_request->status != aborted)
                        && (old_request->status != completed))
                        dev_dbg(&old_request->isci_host->pdev->dev,
                                "%s: Bad request status (%d): tmf=%p, old_request=%p\n",
                                __func__, old_request->status, tmf, old_request);
                break;

        case isci_tmf_timed_out:

                /* Set the task's state to "aborting", since the abort task
                 * function thread set it to "aborted" (above) in anticipation
                 * of the task management request working correctly.  Since the
                 * timeout has now fired, the TMF request failed.  We set the
                 * state such that the request completion will indicate the
                 * device is no longer present.
                 */
                isci_request_change_state(old_request, aborting);
                break;

        default:
                dev_dbg(&old_request->isci_host->pdev->dev,
                        "%s: Bad cb_state (%d): tmf=%p, old_request=%p\n",
                        __func__, cb_state, tmf, old_request);
                break;
        }
}

/**
 * isci_task_abort_task() - This function is one of the SAS Domain Template
 *    functions. This function is called by libsas to abort a specified task.
 * @task: This parameter specifies the SAS task to abort.
 *
 * status, zero indicates success.
 */
int isci_task_abort_task(struct sas_task *task)
{
        struct isci_host *isci_host = dev_to_ihost(task->dev);
        DECLARE_COMPLETION_ONSTACK(aborted_io_completion);
        struct isci_request       *old_request = NULL;
        enum isci_request_status  old_state;
        struct isci_remote_device *isci_device = NULL;
        struct isci_tmf           tmf;
        int                       ret = TMF_RESP_FUNC_FAILED;
        unsigned long             flags;
        bool                      any_dev_reset = false;

        /* Get the isci_request reference from the task.  Note that
         * this check does not depend on the pending request list
         * in the device, because tasks driving resets may land here
         * after completion in the core.
         */
        spin_lock_irqsave(&isci_host->scic_lock, flags);
        spin_lock(&task->task_state_lock);

        old_request = task->lldd_task;

        /* If task is already done, the request isn't valid */
        if (!(task->task_state_flags & SAS_TASK_STATE_DONE) &&
            (task->task_state_flags & SAS_TASK_AT_INITIATOR) &&
            old_request)
                isci_device = isci_lookup_device(task->dev);

        spin_unlock(&task->task_state_lock);
        spin_unlock_irqrestore(&isci_host->scic_lock, flags);

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

        if (!isci_device || !old_request)
                goto out;

        set_bit(IDEV_EH, &isci_device->flags);

        /* This version of the driver will fail abort requests for
         * SATA/STP.  Failing the abort request this way will cause the
         * SCSI error handler thread to escalate to LUN reset
         */
        if (sas_protocol_ata(task->task_proto)) {
                dev_dbg(&isci_host->pdev->dev,
                            " task %p is for a STP/SATA device;"
                            " returning TMF_RESP_FUNC_FAILED\n"
                            " to cause a LUN reset...\n", task);
                goto out;
        }

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

        any_dev_reset = isci_device_is_reset_pending(isci_host, isci_device);

        spin_lock_irqsave(&task->task_state_lock, flags);

        any_dev_reset = any_dev_reset || (task->task_state_flags & SAS_TASK_NEED_DEV_RESET);

        /* If the extraction of the request reference from the task
         * failed, then the request has been completed (or if there is a
         * pending reset then this abort request function must be failed
         * in order to escalate to the target reset).
         */
        if ((old_request == NULL) || any_dev_reset) {

                /* If the device reset task flag is set, fail the task
                 * management request.  Otherwise, the original request
                 * has completed.
                 */
                if (any_dev_reset) {

                        /* Turn off the task's DONE to make sure this
                         * task is escalated to a target reset.
                         */
                        task->task_state_flags &= ~SAS_TASK_STATE_DONE;

                        /* Make the reset happen as soon as possible. */
                        task->task_state_flags |= SAS_TASK_NEED_DEV_RESET;

                        spin_unlock_irqrestore(&task->task_state_lock, flags);

                        /* Fail the task management request in order to
                         * escalate to the target reset.
                         */
                        ret = TMF_RESP_FUNC_FAILED;

                        dev_dbg(&isci_host->pdev->dev,
                                "%s: Failing task abort in order to "
                                "escalate to target reset because\n"
                                "SAS_TASK_NEED_DEV_RESET is set for "
                                "task %p on dev %p\n",
                                __func__, task, isci_device);


                } else {
                        /* The request has already completed and there
                         * is nothing to do here other than to set the task
                         * done bit, and indicate that the task abort function
                         * was sucessful.
                         */
                        isci_set_task_doneflags(task);

                        spin_unlock_irqrestore(&task->task_state_lock, flags);

                        ret = TMF_RESP_FUNC_COMPLETE;

                        dev_dbg(&isci_host->pdev->dev,
                                "%s: abort task not needed for %p\n",
                                __func__, task);
                }
                goto out;
        } else {
                spin_unlock_irqrestore(&task->task_state_lock, flags);
        }

        spin_lock_irqsave(&isci_host->scic_lock, flags);

        /* Check the request status and change to "aborted" if currently
         * "starting"; if true then set the I/O kernel completion
         * struct that will be triggered when the request completes.
         */
        old_state = isci_task_validate_request_to_abort(
                                old_request, isci_host, isci_device,
                                &aborted_io_completion);
        if ((old_state != started) &&
            (old_state != completed) &&
            (old_state != aborting)) {

                spin_unlock_irqrestore(&isci_host->scic_lock, flags);

                /* The request was already being handled by someone else (because
                * they got to set the state away from started).
                */
                dev_dbg(&isci_host->pdev->dev,
                        "%s:  device = %p; old_request %p already being aborted\n",
                        __func__,
                        isci_device, old_request);
                ret = TMF_RESP_FUNC_COMPLETE;
                goto out;
        }
        if (task->task_proto == SAS_PROTOCOL_SMP ||
            test_bit(IREQ_COMPLETE_IN_TARGET, &old_request->flags)) {

                spin_unlock_irqrestore(&isci_host->scic_lock, flags);

                dev_dbg(&isci_host->pdev->dev,
                        "%s: SMP request (%d)"
                        " or complete_in_target (%d), thus no TMF\n",
                        __func__, (task->task_proto == SAS_PROTOCOL_SMP),
                        test_bit(IREQ_COMPLETE_IN_TARGET, &old_request->flags));

                /* Set the state on the task. */
                isci_task_all_done(task);

                ret = TMF_RESP_FUNC_COMPLETE;

                /* Stopping and SMP devices are not sent a TMF, and are not
                 * reset, but the outstanding I/O request is terminated below.
                 */
        } else {
                /* Fill in the tmf stucture */
                isci_task_build_abort_task_tmf(&tmf, isci_tmf_ssp_task_abort,
                                               isci_abort_task_process_cb,
                                               old_request);

                spin_unlock_irqrestore(&isci_host->scic_lock, flags);

                #define ISCI_ABORT_TASK_TIMEOUT_MS 500 /* half second timeout. */
                ret = isci_task_execute_tmf(isci_host, isci_device, &tmf,
                                            ISCI_ABORT_TASK_TIMEOUT_MS);

                if (ret != TMF_RESP_FUNC_COMPLETE)
                        dev_dbg(&isci_host->pdev->dev,
                                "%s: isci_task_send_tmf failed\n",
                                __func__);
        }
        if (ret == TMF_RESP_FUNC_COMPLETE) {
                set_bit(IREQ_COMPLETE_IN_TARGET, &old_request->flags);

                /* Clean up the request on our side, and wait for the aborted
                 * I/O to complete.
                 */
                isci_terminate_request_core(isci_host, isci_device, old_request);
        }

        /* Make sure we do not leave a reference to aborted_io_completion */
        old_request->io_request_completion = NULL;
 out:
        isci_put_device(isci_device);
        return ret;
}

/**
 * isci_task_abort_task_set() - This function is one of the SAS Domain Template
 *    functions. This is one of the Task Management functoins called by libsas,
 *    to abort all task for the given lun.
 * @d_device: This parameter specifies the domain device associated with this
 *    request.
 * @lun: This parameter specifies the lun associated with this request.
 *
 * status, zero indicates success.
 */
int isci_task_abort_task_set(
        struct domain_device *d_device,
        u8 *lun)
{
        return TMF_RESP_FUNC_FAILED;
}


/**
 * isci_task_clear_aca() - This function is one of the SAS Domain Template
 *    functions. This is one of the Task Management functoins called by libsas.
 * @d_device: This parameter specifies the domain device associated with this
 *    request.
 * @lun: This parameter specifies the lun        associated with this request.
 *
 * status, zero indicates success.
 */
int isci_task_clear_aca(
        struct domain_device *d_device,
        u8 *lun)
{
        return TMF_RESP_FUNC_FAILED;
}



/**
 * isci_task_clear_task_set() - This function is one of the SAS Domain Template
 *    functions. This is one of the Task Management functoins called by libsas.
 * @d_device: This parameter specifies the domain device associated with this
 *    request.
 * @lun: This parameter specifies the lun        associated with this request.
 *
 * status, zero indicates success.
 */
int isci_task_clear_task_set(
        struct domain_device *d_device,
        u8 *lun)
{
        return TMF_RESP_FUNC_FAILED;
}


/**
 * isci_task_query_task() - This function is implemented to cause libsas to
 *    correctly escalate the failed abort to a LUN or target reset (this is
 *    because sas_scsi_find_task libsas function does not correctly interpret
 *    all return codes from the abort task call).  When TMF_RESP_FUNC_SUCC is
 *    returned, libsas turns this into a LUN reset; when FUNC_FAILED is
 *    returned, libsas will turn this into a target reset
 * @task: This parameter specifies the sas task being queried.
 * @lun: This parameter specifies the lun associated with this request.
 *
 * status, zero indicates success.
 */
int isci_task_query_task(
        struct sas_task *task)
{
        /* See if there is a pending device reset for this device. */
        if (task->task_state_flags & SAS_TASK_NEED_DEV_RESET)
                return TMF_RESP_FUNC_FAILED;
        else
                return TMF_RESP_FUNC_SUCC;
}

/*
 * isci_task_request_complete() - This function is called by the sci core when
 *    an task request completes.
 * @ihost: This parameter specifies the ISCI host object
 * @ireq: This parameter is the completed isci_request object.
 * @completion_status: This parameter specifies the completion status from the
 *    sci core.
 *
 * none.
 */
void
isci_task_request_complete(struct isci_host *ihost,
                           struct isci_request *ireq,
                           enum sci_task_status completion_status)
{
        struct isci_tmf *tmf = isci_request_access_tmf(ireq);
        struct completion *tmf_complete;

        dev_dbg(&ihost->pdev->dev,
                "%s: request = %p, status=%d\n",
                __func__, ireq, completion_status);

        isci_request_change_state(ireq, completed);

        tmf->status = completion_status;
        set_bit(IREQ_COMPLETE_IN_TARGET, &ireq->flags);

        if (tmf->proto == SAS_PROTOCOL_SSP) {
                memcpy(&tmf->resp.resp_iu,
                       &ireq->ssp.rsp,
                       SSP_RESP_IU_MAX_SIZE);
        } else if (tmf->proto == SAS_PROTOCOL_SATA) {
                memcpy(&tmf->resp.d2h_fis,
                       &ireq->stp.rsp,
                       sizeof(struct dev_to_host_fis));
        }

        /* PRINT_TMF( ((struct isci_tmf *)request->task)); */
        tmf_complete = tmf->complete;

        sci_controller_complete_io(ihost, ireq->target_device, ireq);
        /* set the 'terminated' flag handle to make sure it cannot be terminated
         *  or completed again.
         */
        set_bit(IREQ_TERMINATED, &ireq->flags);

        isci_request_change_state(ireq, unallocated);
        list_del_init(&ireq->dev_node);

        /* The task management part completes last. */
        complete(tmf_complete);
}

static void isci_smp_task_timedout(unsigned long _task)
{
        struct sas_task *task = (void *) _task;
        unsigned long flags;

        spin_lock_irqsave(&task->task_state_lock, flags);
        if (!(task->task_state_flags & SAS_TASK_STATE_DONE))
                task->task_state_flags |= SAS_TASK_STATE_ABORTED;
        spin_unlock_irqrestore(&task->task_state_lock, flags);

        complete(&task->completion);
}

static void isci_smp_task_done(struct sas_task *task)
{
        if (!del_timer(&task->timer))
                return;
        complete(&task->completion);
}

static struct sas_task *isci_alloc_task(void)
{
        struct sas_task *task = kzalloc(sizeof(*task), GFP_KERNEL);

        if (task) {
                INIT_LIST_HEAD(&task->list);
                spin_lock_init(&task->task_state_lock);
                task->task_state_flags = SAS_TASK_STATE_PENDING;
                init_timer(&task->timer);
                init_completion(&task->completion);
        }

        return task;
}

static void isci_free_task(struct isci_host *ihost, struct sas_task  *task)
{
        if (task) {
                BUG_ON(!list_empty(&task->list));
                kfree(task);
        }
}

static int isci_smp_execute_task(struct isci_host *ihost,
                                 struct domain_device *dev, void *req,
                                 int req_size, void *resp, int resp_size)
{
        int res, retry;
        struct sas_task *task = NULL;

        for (retry = 0; retry < 3; retry++) {
                task = isci_alloc_task();
                if (!task)
                        return -ENOMEM;

                task->dev = dev;
                task->task_proto = dev->tproto;
                sg_init_one(&task->smp_task.smp_req, req, req_size);
                sg_init_one(&task->smp_task.smp_resp, resp, resp_size);

                task->task_done = isci_smp_task_done;

                task->timer.data = (unsigned long) task;
                task->timer.function = isci_smp_task_timedout;
                task->timer.expires = jiffies + 10*HZ;
                add_timer(&task->timer);

                res = isci_task_execute_task(task, 1, GFP_KERNEL);

                if (res) {
                        del_timer(&task->timer);
                        dev_dbg(&ihost->pdev->dev,
                                "%s: executing SMP task failed:%d\n",
                                __func__, res);
                        goto ex_err;
                }

                wait_for_completion(&task->completion);
                res = -ECOMM;
                if ((task->task_state_flags & SAS_TASK_STATE_ABORTED)) {
                        dev_dbg(&ihost->pdev->dev,
                                "%s: smp task timed out or aborted\n",
                                __func__);
                        isci_task_abort_task(task);
                        if (!(task->task_state_flags & SAS_TASK_STATE_DONE)) {
                                dev_dbg(&ihost->pdev->dev,
                                        "%s: SMP task aborted and not done\n",
                                        __func__);
                                goto ex_err;
                        }
                }
                if (task->task_status.resp == SAS_TASK_COMPLETE &&
                    task->task_status.stat == SAM_STAT_GOOD) {
                        res = 0;
                        break;
                }
                if (task->task_status.resp == SAS_TASK_COMPLETE &&
                      task->task_status.stat == SAS_DATA_UNDERRUN) {
                        /* no error, but return the number of bytes of
                        * underrun */
                        res = task->task_status.residual;
                        break;
                }
                if (task->task_status.resp == SAS_TASK_COMPLETE &&
                      task->task_status.stat == SAS_DATA_OVERRUN) {
                        res = -EMSGSIZE;
                        break;
                } else {
                        dev_dbg(&ihost->pdev->dev,
                                "%s: task to dev %016llx response: 0x%x "
                                "status 0x%x\n", __func__,
                                SAS_ADDR(dev->sas_addr),
                                task->task_status.resp,
                                task->task_status.stat);
                        isci_free_task(ihost, task);
                        task = NULL;
                }
        }
ex_err:
        BUG_ON(retry == 3 && task != NULL);
        isci_free_task(ihost, task);
        return res;
}

#define DISCOVER_REQ_SIZE  16
#define DISCOVER_RESP_SIZE 56

int isci_smp_get_phy_attached_dev_type(struct isci_host *ihost,
                                       struct domain_device *dev,
                                       int phy_id, int *adt)
{
        struct smp_resp *disc_resp;
        u8 *disc_req;
        int res;

        disc_resp = kzalloc(DISCOVER_RESP_SIZE, GFP_KERNEL);
        if (!disc_resp)
                return -ENOMEM;

        disc_req = kzalloc(DISCOVER_REQ_SIZE, GFP_KERNEL);
        if (disc_req) {
                disc_req[0] = SMP_REQUEST;
                disc_req[1] = SMP_DISCOVER;
                disc_req[9] = phy_id;
        } else {
                kfree(disc_resp);
                return -ENOMEM;
        }
        res = isci_smp_execute_task(ihost, dev, disc_req, DISCOVER_REQ_SIZE,
                                    disc_resp, DISCOVER_RESP_SIZE);
        if (!res) {
                if (disc_resp->result != SMP_RESP_FUNC_ACC)
                        res = disc_resp->result;
                else
                        *adt = disc_resp->disc.attached_dev_type;
        }
        kfree(disc_req);
        kfree(disc_resp);

        return res;
}

static void isci_wait_for_smp_phy_reset(struct isci_remote_device *idev, int phy_num)
{
        struct domain_device *dev = idev->domain_dev;
        struct isci_port *iport = idev->isci_port;
        struct isci_host *ihost = iport->isci_host;
        int res, iteration = 0, attached_device_type;
        #define STP_WAIT_MSECS 25000
        unsigned long tmo = msecs_to_jiffies(STP_WAIT_MSECS);
        unsigned long deadline = jiffies + tmo;
        enum {
                SMP_PHYWAIT_PHYDOWN,
                SMP_PHYWAIT_PHYUP,
                SMP_PHYWAIT_DONE
        } phy_state = SMP_PHYWAIT_PHYDOWN;

        /* While there is time, wait for the phy to go away and come back */
        while (time_is_after_jiffies(deadline) && phy_state != SMP_PHYWAIT_DONE) {
                int event = atomic_read(&iport->event);

                ++iteration;

                tmo = wait_event_timeout(ihost->eventq,
                                         event != atomic_read(&iport->event) ||
                                         !test_bit(IPORT_BCN_BLOCKED, &iport->flags),
                                         tmo);
                /* link down, stop polling */
                if (!test_bit(IPORT_BCN_BLOCKED, &iport->flags))
                        break;

                dev_dbg(&ihost->pdev->dev,
                        "%s: iport %p, iteration %d,"
                        " phase %d: time_remaining %lu, bcns = %d\n",
                        __func__, iport, iteration, phy_state,
                        tmo, test_bit(IPORT_BCN_PENDING, &iport->flags));

                res = isci_smp_get_phy_attached_dev_type(ihost, dev, phy_num,
                                                         &attached_device_type);
                tmo = deadline - jiffies;

                if (res) {
                        dev_dbg(&ihost->pdev->dev,
                                 "%s: iteration %d, phase %d:"
                                 " SMP error=%d, time_remaining=%lu\n",
                                 __func__, iteration, phy_state, res, tmo);
                        break;
                }
                dev_dbg(&ihost->pdev->dev,
                        "%s: iport %p, iteration %d,"
                        " phase %d: time_remaining %lu, bcns = %d, "
                        "attdevtype = %x\n",
                        __func__, iport, iteration, phy_state,
                        tmo, test_bit(IPORT_BCN_PENDING, &iport->flags),
                        attached_device_type);

                switch (phy_state) {
                case SMP_PHYWAIT_PHYDOWN:
                        /* Has the device gone away? */
                        if (!attached_device_type)
                                phy_state = SMP_PHYWAIT_PHYUP;

                        break;

                case SMP_PHYWAIT_PHYUP:
                        /* Has the device come back? */
                        if (attached_device_type)
                                phy_state = SMP_PHYWAIT_DONE;
                        break;

                case SMP_PHYWAIT_DONE:
                        break;
                }

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

static int isci_reset_device(struct isci_host *ihost,
                             struct isci_remote_device *idev)
{
        struct sas_phy *phy = sas_find_local_phy(idev->domain_dev);
        struct isci_port *iport = idev->isci_port;
        enum sci_status status;
        unsigned long flags;
        int rc;

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

        spin_lock_irqsave(&ihost->scic_lock, flags);
        status = sci_remote_device_reset(idev);
        if (status != SCI_SUCCESS) {
                spin_unlock_irqrestore(&ihost->scic_lock, flags);

                dev_dbg(&ihost->pdev->dev,
                         "%s: sci_remote_device_reset(%p) returned %d!\n",
                         __func__, idev, status);

                return TMF_RESP_FUNC_FAILED;
        }
        spin_unlock_irqrestore(&ihost->scic_lock, flags);

        /* Make sure all pending requests are able to be fully terminated. */
        isci_device_clear_reset_pending(ihost, idev);

        /* If this is a device on an expander, disable BCN processing. */
        if (!scsi_is_sas_phy_local(phy))
                set_bit(IPORT_BCN_BLOCKED, &iport->flags);

        rc = sas_phy_reset(phy, true);

        /* Terminate in-progress I/O now. */
        isci_remote_device_nuke_requests(ihost, idev);

        /* Since all pending TCs have been cleaned, resume the RNC. */
        spin_lock_irqsave(&ihost->scic_lock, flags);
        status = sci_remote_device_reset_complete(idev);
        spin_unlock_irqrestore(&ihost->scic_lock, flags);

        /* If this is a device on an expander, bring the phy back up. */
        if (!scsi_is_sas_phy_local(phy)) {
                /* A phy reset will cause the device to go away then reappear.
                 * Since libsas will take action on incoming BCNs (eg. remove
                 * a device going through an SMP phy-control driven reset),
                 * we need to wait until the phy comes back up before letting
                 * discovery proceed in libsas.
                 */
                isci_wait_for_smp_phy_reset(idev, phy->number);

                spin_lock_irqsave(&ihost->scic_lock, flags);
                isci_port_bcn_enable(ihost, idev->isci_port);
                spin_unlock_irqrestore(&ihost->scic_lock, flags);
        }

        if (status != SCI_SUCCESS) {
                dev_dbg(&ihost->pdev->dev,
                         "%s: sci_remote_device_reset_complete(%p) "
                         "returned %d!\n", __func__, idev, status);
        }

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

        return rc;
}

int isci_task_I_T_nexus_reset(struct domain_device *dev)
{
        struct isci_host *ihost = dev_to_ihost(dev);
        struct isci_remote_device *idev;
        unsigned long flags;
        int ret;

        spin_lock_irqsave(&ihost->scic_lock, flags);
        idev = isci_lookup_device(dev);
        spin_unlock_irqrestore(&ihost->scic_lock, flags);

        if (!idev || !test_bit(IDEV_EH, &idev->flags)) {
                ret = TMF_RESP_FUNC_COMPLETE;
                goto out;
        }

        ret = isci_reset_device(ihost, idev);
 out:
        isci_put_device(idev);
        return ret;
}

int isci_bus_reset_handler(struct scsi_cmnd *cmd)
{
        struct domain_device *dev = sdev_to_domain_dev(cmd->device);
        struct isci_host *ihost = dev_to_ihost(dev);
        struct isci_remote_device *idev;
        unsigned long flags;
        int ret;

        spin_lock_irqsave(&ihost->scic_lock, flags);
        idev = isci_lookup_device(dev);
        spin_unlock_irqrestore(&ihost->scic_lock, flags);

        if (!idev) {
                ret = TMF_RESP_FUNC_COMPLETE;
                goto out;
        }

        ret = isci_reset_device(ihost, idev);
 out:
        isci_put_device(idev);
        return ret;
}