remote_node_context.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_ata.h>
#include "host.h"
#include "isci.h"
#include "remote_device.h"
#include "remote_node_context.h"
#include "scu_event_codes.h"
#include "scu_task_context.h"

#undef C
#define C(a) (#a)
const char *rnc_state_name(enum scis_sds_remote_node_context_states state)
{
    static const char * const strings[] = RNC_STATES;

    return strings[state];
}
#undef C

bool sci_remote_node_context_is_ready(
    struct sci_remote_node_context *sci_rnc)
{
    u32 current_state = sci_rnc->sm.current_state_id;

    if (current_state == SCI_RNC_READY) {
        return true;
    }

    return false;
}

bool sci_remote_node_context_is_suspended(struct sci_remote_node_context *sci_rnc)
{
    u32 current_state = sci_rnc->sm.current_state_id;

    if (current_state == SCI_RNC_TX_RX_SUSPENDED)
        return true;
    return false;
}

static union scu_remote_node_context *sci_rnc_by_id(struct isci_host *ihost, u16 id)
{
    if (id < ihost->remote_node_entries &&
        ihost->device_table[id])
        return &ihost->remote_node_context_table[id];

    return NULL;
}

static void sci_remote_node_context_construct_buffer(struct sci_remote_node_context *sci_rnc)
{
    struct isci_remote_device *idev = rnc_to_dev(sci_rnc);
    struct domain_device *dev = idev->domain_dev;
    int rni = sci_rnc->remote_node_index;
    union scu_remote_node_context *rnc;
    struct isci_host *ihost;
    __le64 sas_addr;

    ihost = idev->owning_port->owning_controller;
    rnc = sci_rnc_by_id(ihost, rni);

    memset(rnc, 0, sizeof(union scu_remote_node_context)
        * sci_remote_device_node_count(idev));

    rnc->ssp.remote_node_index = rni;
    rnc->ssp.remote_node_port_width = idev->device_port_width;
    rnc->ssp.logical_port_index = idev->owning_port->physical_port_index;

    /* sas address is __be64, context ram format is __le64 */
    sas_addr = cpu_to_le64(SAS_ADDR(dev->sas_addr));
    rnc->ssp.remote_sas_address_hi = upper_32_bits(sas_addr);
    rnc->ssp.remote_sas_address_lo = lower_32_bits(sas_addr);

    rnc->ssp.nexus_loss_timer_enable = true;
    rnc->ssp.check_bit               = false;
    rnc->ssp.is_valid                = false;
    rnc->ssp.is_remote_node_context  = true;
    rnc->ssp.function_number         = 0;

    rnc->ssp.arbitration_wait_time = 0;

    if (dev_is_sata(dev)) {
        rnc->ssp.connection_occupancy_timeout =
            ihost->user_parameters.stp_max_occupancy_timeout;
        rnc->ssp.connection_inactivity_timeout =
            ihost->user_parameters.stp_inactivity_timeout;
    } else {
        rnc->ssp.connection_occupancy_timeout  =
            ihost->user_parameters.ssp_max_occupancy_timeout;
        rnc->ssp.connection_inactivity_timeout =
            ihost->user_parameters.ssp_inactivity_timeout;
    }

    rnc->ssp.initial_arbitration_wait_time = 0;

    /* Open Address Frame Parameters */
    rnc->ssp.oaf_connection_rate = idev->connection_rate;
    rnc->ssp.oaf_features = 0;
    rnc->ssp.oaf_source_zone_group = 0;
    rnc->ssp.oaf_more_compatibility_features = 0;
}
static void sci_remote_node_context_setup_to_resume(
    struct sci_remote_node_context *sci_rnc,
    scics_sds_remote_node_context_callback callback,
    void *callback_parameter,
    enum sci_remote_node_context_destination_state dest_param)
{
    if (sci_rnc->destination_state != RNC_DEST_FINAL) {
        sci_rnc->destination_state = dest_param;
        if (callback != NULL) {
            sci_rnc->user_callback = callback;
            sci_rnc->user_cookie   = callback_parameter;
        }
    }
}

static void sci_remote_node_context_setup_to_destroy(
    struct sci_remote_node_context *sci_rnc,
    scics_sds_remote_node_context_callback callback,
    void *callback_parameter)
{
    struct isci_host *ihost = idev_to_ihost(rnc_to_dev(sci_rnc));

    sci_rnc->destination_state = RNC_DEST_FINAL;
    sci_rnc->user_callback     = callback;
    sci_rnc->user_cookie       = callback_parameter;

    wake_up(&ihost->eventq);
}

static void sci_remote_node_context_notify_user(
    struct sci_remote_node_context *rnc)
{
    if (rnc->user_callback != NULL) {
        (*rnc->user_callback)(rnc->user_cookie);

        rnc->user_callback = NULL;
        rnc->user_cookie = NULL;
    }
}

static void sci_remote_node_context_continue_state_transitions(struct sci_remote_node_context *rnc)
{
    switch (rnc->destination_state) {
    case RNC_DEST_READY:
    case RNC_DEST_SUSPENDED_RESUME:
        rnc->destination_state = RNC_DEST_READY;
        /* Fall through... */
    case RNC_DEST_FINAL:
        sci_remote_node_context_resume(rnc, rnc->user_callback,
                           rnc->user_cookie);
        break;
    default:
        rnc->destination_state = RNC_DEST_UNSPECIFIED;
        break;
    }
}

static void sci_remote_node_context_validate_context_buffer(struct sci_remote_node_context *sci_rnc)
{
    union scu_remote_node_context *rnc_buffer;
    struct isci_remote_device *idev = rnc_to_dev(sci_rnc);
    struct domain_device *dev = idev->domain_dev;
    struct isci_host *ihost = idev->owning_port->owning_controller;

    rnc_buffer = sci_rnc_by_id(ihost, sci_rnc->remote_node_index);

    rnc_buffer->ssp.is_valid = true;

    if (dev_is_sata(dev) && dev->parent) {
        sci_remote_device_post_request(idev, SCU_CONTEXT_COMMAND_POST_RNC_96);
    } else {
        sci_remote_device_post_request(idev, SCU_CONTEXT_COMMAND_POST_RNC_32);

        if (!dev->parent)
            sci_port_setup_transports(idev->owning_port,
                          sci_rnc->remote_node_index);
    }
}

static void sci_remote_node_context_invalidate_context_buffer(struct sci_remote_node_context *sci_rnc)
{
    union scu_remote_node_context *rnc_buffer;
    struct isci_remote_device *idev = rnc_to_dev(sci_rnc);
    struct isci_host *ihost = idev->owning_port->owning_controller;

    rnc_buffer = sci_rnc_by_id(ihost, sci_rnc->remote_node_index);

    rnc_buffer->ssp.is_valid = false;

    sci_remote_device_post_request(rnc_to_dev(sci_rnc),
                       SCU_CONTEXT_COMMAND_POST_RNC_INVALIDATE);
}

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

    /* Check to see if we have gotten back to the initial state because
     * someone requested to destroy the remote node context object.
     */
    if (sm->previous_state_id == SCI_RNC_INVALIDATING) {
        rnc->destination_state = RNC_DEST_UNSPECIFIED;
        sci_remote_node_context_notify_user(rnc);

        smp_wmb();
        wake_up(&ihost->eventq);
    }
}

static void sci_remote_node_context_posting_state_enter(struct sci_base_state_machine *sm)
{
    struct sci_remote_node_context *sci_rnc = container_of(sm, typeof(*sci_rnc), sm);

    sci_remote_node_context_validate_context_buffer(sci_rnc);
}

static void sci_remote_node_context_invalidating_state_enter(struct sci_base_state_machine *sm)
{
    struct sci_remote_node_context *rnc = container_of(sm, typeof(*rnc), sm);

    /* Terminate all outstanding requests. */
    sci_remote_device_terminate_requests(rnc_to_dev(rnc));
    sci_remote_node_context_invalidate_context_buffer(rnc);
}

static void sci_remote_node_context_resuming_state_enter(struct sci_base_state_machine *sm)
{
    struct sci_remote_node_context *rnc = container_of(sm, typeof(*rnc), sm);
    struct isci_remote_device *idev;
    struct domain_device *dev;

    idev = rnc_to_dev(rnc);
    dev = idev->domain_dev;

    /*
     * For direct attached SATA devices we need to clear the TLCR
     * NCQ to TCi tag mapping on the phy and in cases where we
     * resume because of a target reset we also need to update
     * the STPTLDARNI register with the RNi of the device
     */
    if (dev_is_sata(dev) && !dev->parent)
        sci_port_setup_transports(idev->owning_port, rnc->remote_node_index);

    sci_remote_device_post_request(idev, SCU_CONTEXT_COMMAND_POST_RNC_RESUME);
}

static void sci_remote_node_context_ready_state_enter(struct sci_base_state_machine *sm)
{
    struct sci_remote_node_context *rnc = container_of(sm, typeof(*rnc), sm);
    enum sci_remote_node_context_destination_state dest_select;
    int tell_user = 1;

    dest_select = rnc->destination_state;
    rnc->destination_state = RNC_DEST_UNSPECIFIED;

    if ((dest_select == RNC_DEST_SUSPENDED) ||
        (dest_select == RNC_DEST_SUSPENDED_RESUME)) {
        sci_remote_node_context_suspend(
            rnc, rnc->suspend_reason,
            SCI_SOFTWARE_SUSPEND_EXPECTED_EVENT);

        if (dest_select == RNC_DEST_SUSPENDED_RESUME)
            tell_user = 0;  /* Wait until ready again. */
    }
    if (tell_user)
        sci_remote_node_context_notify_user(rnc);
}

static void sci_remote_node_context_tx_suspended_state_enter(struct sci_base_state_machine *sm)
{
    struct sci_remote_node_context *rnc = container_of(sm, typeof(*rnc), sm);

    sci_remote_node_context_continue_state_transitions(rnc);
}

static void sci_remote_node_context_tx_rx_suspended_state_enter(struct sci_base_state_machine *sm)
{
    struct sci_remote_node_context *rnc = container_of(sm, typeof(*rnc), sm);
    struct isci_remote_device *idev = rnc_to_dev(rnc);
    struct isci_host *ihost = idev->owning_port->owning_controller;
    u32 new_count = rnc->suspend_count + 1;

    if (new_count == 0)
        rnc->suspend_count = 1;
    else
        rnc->suspend_count = new_count;
    smp_wmb();

    /* Terminate outstanding requests pending abort. */
    sci_remote_device_abort_requests_pending_abort(idev);

    wake_up(&ihost->eventq);
    sci_remote_node_context_continue_state_transitions(rnc);
}

static void sci_remote_node_context_await_suspend_state_exit(
    struct sci_base_state_machine *sm)
{
    struct sci_remote_node_context *rnc
        = container_of(sm, typeof(*rnc), sm);
    struct isci_remote_device *idev = rnc_to_dev(rnc);

    if (dev_is_sata(idev->domain_dev))
        isci_dev_set_hang_detection_timeout(idev, 0);
}

static const struct sci_base_state sci_remote_node_context_state_table[] = {
    [SCI_RNC_INITIAL] = {
        .enter_state = sci_remote_node_context_initial_state_enter,
    },
    [SCI_RNC_POSTING] = {
        .enter_state = sci_remote_node_context_posting_state_enter,
    },
    [SCI_RNC_INVALIDATING] = {
        .enter_state = sci_remote_node_context_invalidating_state_enter,
    },
    [SCI_RNC_RESUMING] = {
        .enter_state = sci_remote_node_context_resuming_state_enter,
    },
    [SCI_RNC_READY] = {
        .enter_state = sci_remote_node_context_ready_state_enter,
    },
    [SCI_RNC_TX_SUSPENDED] = {
        .enter_state = sci_remote_node_context_tx_suspended_state_enter,
    },
    [SCI_RNC_TX_RX_SUSPENDED] = {
        .enter_state = sci_remote_node_context_tx_rx_suspended_state_enter,
    },
    [SCI_RNC_AWAIT_SUSPENSION] = {
        .exit_state = sci_remote_node_context_await_suspend_state_exit,
    },
};

void sci_remote_node_context_construct(struct sci_remote_node_context *rnc,
                        u16 remote_node_index)
{
    memset(rnc, 0, sizeof(struct sci_remote_node_context));

    rnc->remote_node_index = remote_node_index;
    rnc->destination_state = RNC_DEST_UNSPECIFIED;

    sci_init_sm(&rnc->sm, sci_remote_node_context_state_table, SCI_RNC_INITIAL);
}

enum sci_status sci_remote_node_context_event_handler(struct sci_remote_node_context *sci_rnc,
                               u32 event_code)
{
    enum scis_sds_remote_node_context_states state;
    u32 next_state;

    state = sci_rnc->sm.current_state_id;
    switch (state) {
    case SCI_RNC_POSTING:
        switch (scu_get_event_code(event_code)) {
        case SCU_EVENT_POST_RNC_COMPLETE:
            sci_change_state(&sci_rnc->sm, SCI_RNC_READY);
            break;
        default:
            goto out;
        }
        break;
    case SCI_RNC_INVALIDATING:
        if (scu_get_event_code(event_code) == SCU_EVENT_POST_RNC_INVALIDATE_COMPLETE) {
            if (sci_rnc->destination_state == RNC_DEST_FINAL)
                next_state = SCI_RNC_INITIAL;
            else
                next_state = SCI_RNC_POSTING;
            sci_change_state(&sci_rnc->sm, next_state);
        } else {
            switch (scu_get_event_type(event_code)) {
            case SCU_EVENT_TYPE_RNC_SUSPEND_TX:
            case SCU_EVENT_TYPE_RNC_SUSPEND_TX_RX:
                /* We really dont care if the hardware is going to suspend
                 * the device since it's being invalidated anyway */
                dev_warn(scirdev_to_dev(rnc_to_dev(sci_rnc)),
                    "%s: SCIC Remote Node Context 0x%p was "
                    "suspeneded by hardware while being "
                    "invalidated.\n", __func__, sci_rnc);
                break;
            default:
                goto out;
            }
        }
        break;
    case SCI_RNC_RESUMING:
        if (scu_get_event_code(event_code) == SCU_EVENT_POST_RCN_RELEASE) {
            sci_change_state(&sci_rnc->sm, SCI_RNC_READY);
        } else {
            switch (scu_get_event_type(event_code)) {
            case SCU_EVENT_TYPE_RNC_SUSPEND_TX:
            case SCU_EVENT_TYPE_RNC_SUSPEND_TX_RX:
                /* We really dont care if the hardware is going to suspend
                 * the device since it's being resumed anyway */
                dev_warn(scirdev_to_dev(rnc_to_dev(sci_rnc)),
                    "%s: SCIC Remote Node Context 0x%p was "
                    "suspeneded by hardware while being resumed.\n",
                    __func__, sci_rnc);
                break;
            default:
                goto out;
            }
        }
        break;
    case SCI_RNC_READY:
        switch (scu_get_event_type(event_code)) {
        case SCU_EVENT_TL_RNC_SUSPEND_TX:
            sci_change_state(&sci_rnc->sm, SCI_RNC_TX_SUSPENDED);
            sci_rnc->suspend_type = scu_get_event_type(event_code);
            break;
        case SCU_EVENT_TL_RNC_SUSPEND_TX_RX:
            sci_change_state(&sci_rnc->sm, SCI_RNC_TX_RX_SUSPENDED);
            sci_rnc->suspend_type = scu_get_event_type(event_code);
            break;
        default:
            goto out;
        }
        break;
    case SCI_RNC_AWAIT_SUSPENSION:
        switch (scu_get_event_type(event_code)) {
        case SCU_EVENT_TL_RNC_SUSPEND_TX:
            next_state = SCI_RNC_TX_SUSPENDED;
            break;
        case SCU_EVENT_TL_RNC_SUSPEND_TX_RX:
            next_state = SCI_RNC_TX_RX_SUSPENDED;
            break;
        default:
            goto out;
        }
        if (sci_rnc->suspend_type == scu_get_event_type(event_code))
            sci_change_state(&sci_rnc->sm, next_state);
        break;
    default:
        dev_warn(scirdev_to_dev(rnc_to_dev(sci_rnc)),
             "%s: invalid state: %s\n", __func__,
             rnc_state_name(state));
        return SCI_FAILURE_INVALID_STATE;
    }
    return SCI_SUCCESS;

 out:
    dev_warn(scirdev_to_dev(rnc_to_dev(sci_rnc)),
         "%s: code: %#x state: %s\n", __func__, event_code,
         rnc_state_name(state));
    return SCI_FAILURE;

}

enum sci_status sci_remote_node_context_destruct(struct sci_remote_node_context *sci_rnc,
                              scics_sds_remote_node_context_callback cb_fn,
                              void *cb_p)
{
    enum scis_sds_remote_node_context_states state;

    state = sci_rnc->sm.current_state_id;
    switch (state) {
    case SCI_RNC_INVALIDATING:
        sci_remote_node_context_setup_to_destroy(sci_rnc, cb_fn, cb_p);
        return SCI_SUCCESS;
    case SCI_RNC_POSTING:
    case SCI_RNC_RESUMING:
    case SCI_RNC_READY:
    case SCI_RNC_TX_SUSPENDED:
    case SCI_RNC_TX_RX_SUSPENDED:
        sci_remote_node_context_setup_to_destroy(sci_rnc, cb_fn, cb_p);
        sci_change_state(&sci_rnc->sm, SCI_RNC_INVALIDATING);
        return SCI_SUCCESS;
    case SCI_RNC_AWAIT_SUSPENSION:
        sci_remote_node_context_setup_to_destroy(sci_rnc, cb_fn, cb_p);
        return SCI_SUCCESS;
    case SCI_RNC_INITIAL:
        dev_warn(scirdev_to_dev(rnc_to_dev(sci_rnc)),
             "%s: invalid state: %s\n", __func__,
             rnc_state_name(state));
        /* We have decided that the destruct request on the remote node context
         * can not fail since it is either in the initial/destroyed state or is
         * can be destroyed.
         */
        return SCI_SUCCESS;
    default:
        dev_warn(scirdev_to_dev(rnc_to_dev(sci_rnc)),
             "%s: invalid state %s\n", __func__,
             rnc_state_name(state));
        return SCI_FAILURE_INVALID_STATE;
    }
}

enum sci_status sci_remote_node_context_suspend(
            struct sci_remote_node_context *sci_rnc,
            enum sci_remote_node_suspension_reasons suspend_reason,
            u32 suspend_type)
{
    enum scis_sds_remote_node_context_states state
        = sci_rnc->sm.current_state_id;
    struct isci_remote_device *idev = rnc_to_dev(sci_rnc);
    enum sci_status status = SCI_FAILURE_INVALID_STATE;
    enum sci_remote_node_context_destination_state dest_param =
        RNC_DEST_UNSPECIFIED;

    dev_dbg(scirdev_to_dev(idev),
        "%s: current state %s, current suspend_type %x dest state %d,"
            " arg suspend_reason %d, arg suspend_type %x",
        __func__, rnc_state_name(state), sci_rnc->suspend_type,
        sci_rnc->destination_state, suspend_reason,
        suspend_type);

    /* Disable automatic state continuations if explicitly suspending. */
    if ((suspend_reason == SCI_HW_SUSPEND) ||
        (sci_rnc->destination_state == RNC_DEST_FINAL))
        dest_param = sci_rnc->destination_state;

    switch (state) {
    case SCI_RNC_READY:
        break;
    case SCI_RNC_INVALIDATING:
        if (sci_rnc->destination_state == RNC_DEST_FINAL) {
            dev_warn(scirdev_to_dev(idev),
                 "%s: already destroying %p\n",
                 __func__, sci_rnc);
            return SCI_FAILURE_INVALID_STATE;
        }
        /* Fall through and handle like SCI_RNC_POSTING */
    case SCI_RNC_RESUMING:
        /* Fall through and handle like SCI_RNC_POSTING */
    case SCI_RNC_POSTING:
        /* Set the destination state to AWAIT - this signals the
         * entry into the SCI_RNC_READY state that a suspension
         * needs to be done immediately.
         */
        if (sci_rnc->destination_state != RNC_DEST_FINAL)
            sci_rnc->destination_state = RNC_DEST_SUSPENDED;
        sci_rnc->suspend_type = suspend_type;
        sci_rnc->suspend_reason = suspend_reason;
        return SCI_SUCCESS;

    case SCI_RNC_TX_SUSPENDED:
        if (suspend_type == SCU_EVENT_TL_RNC_SUSPEND_TX)
            status = SCI_SUCCESS;
        break;
    case SCI_RNC_TX_RX_SUSPENDED:
        if (suspend_type == SCU_EVENT_TL_RNC_SUSPEND_TX_RX)
            status = SCI_SUCCESS;
        break;
    case SCI_RNC_AWAIT_SUSPENSION:
        if ((sci_rnc->suspend_type == SCU_EVENT_TL_RNC_SUSPEND_TX_RX)
            || (suspend_type == sci_rnc->suspend_type))
            return SCI_SUCCESS;
        break;
    default:
        dev_warn(scirdev_to_dev(rnc_to_dev(sci_rnc)),
             "%s: invalid state %s\n", __func__,
             rnc_state_name(state));
        return SCI_FAILURE_INVALID_STATE;
    }
    sci_rnc->destination_state = dest_param;
    sci_rnc->suspend_type = suspend_type;
    sci_rnc->suspend_reason = suspend_reason;

    if (status == SCI_SUCCESS) { /* Already in the destination state? */
        struct isci_host *ihost = idev->owning_port->owning_controller;

        wake_up_all(&ihost->eventq); /* Let observers look. */
        return SCI_SUCCESS;
    }
    if ((suspend_reason == SCI_SW_SUSPEND_NORMAL) ||
        (suspend_reason == SCI_SW_SUSPEND_LINKHANG_DETECT)) {

        if (suspend_reason == SCI_SW_SUSPEND_LINKHANG_DETECT)
            isci_dev_set_hang_detection_timeout(idev, 0x00000001);

        sci_remote_device_post_request(
            idev, SCI_SOFTWARE_SUSPEND_CMD);
    }
    if (state != SCI_RNC_AWAIT_SUSPENSION)
        sci_change_state(&sci_rnc->sm, SCI_RNC_AWAIT_SUSPENSION);

    return SCI_SUCCESS;
}

enum sci_status sci_remote_node_context_resume(struct sci_remote_node_context *sci_rnc,
                            scics_sds_remote_node_context_callback cb_fn,
                            void *cb_p)
{
    enum scis_sds_remote_node_context_states state;
    struct isci_remote_device *idev = rnc_to_dev(sci_rnc);

    state = sci_rnc->sm.current_state_id;
    dev_dbg(scirdev_to_dev(idev),
        "%s: state %s, cb_fn = %p, cb_p = %p; dest_state = %d; "
            "dev resume path %s\n",
        __func__, rnc_state_name(state), cb_fn, cb_p,
        sci_rnc->destination_state,
        test_bit(IDEV_ABORT_PATH_ACTIVE, &idev->flags)
            ? "<abort active>" : "<normal>");

    switch (state) {
    case SCI_RNC_INITIAL:
        if (sci_rnc->remote_node_index == SCIC_SDS_REMOTE_NODE_CONTEXT_INVALID_INDEX)
            return SCI_FAILURE_INVALID_STATE;

        sci_remote_node_context_setup_to_resume(sci_rnc, cb_fn, cb_p,
                            RNC_DEST_READY);
        if (!test_bit(IDEV_ABORT_PATH_ACTIVE, &idev->flags)) {
            sci_remote_node_context_construct_buffer(sci_rnc);
            sci_change_state(&sci_rnc->sm, SCI_RNC_POSTING);
        }
        return SCI_SUCCESS;

    case SCI_RNC_POSTING:
    case SCI_RNC_INVALIDATING:
    case SCI_RNC_RESUMING:
        /* We are still waiting to post when a resume was
         * requested.
         */
        switch (sci_rnc->destination_state) {
        case RNC_DEST_SUSPENDED:
        case RNC_DEST_SUSPENDED_RESUME:
            /* Previously waiting to suspend after posting.
             * Now continue onto resumption.
             */
            sci_remote_node_context_setup_to_resume(
                sci_rnc, cb_fn, cb_p,
                RNC_DEST_SUSPENDED_RESUME);
            break;
        default:
            sci_remote_node_context_setup_to_resume(
                sci_rnc, cb_fn, cb_p,
                RNC_DEST_READY);
            break;
        }
        return SCI_SUCCESS;

    case SCI_RNC_TX_SUSPENDED:
    case SCI_RNC_TX_RX_SUSPENDED:
        {
            struct domain_device *dev = idev->domain_dev;
            /* If this is an expander attached SATA device we must
             * invalidate and repost the RNC since this is the only
             * way to clear the TCi to NCQ tag mapping table for
             * the RNi. All other device types we can just resume.
             */
            sci_remote_node_context_setup_to_resume(
                sci_rnc, cb_fn, cb_p, RNC_DEST_READY);

            if (!test_bit(IDEV_ABORT_PATH_ACTIVE, &idev->flags)) {
                if ((dev_is_sata(dev) && dev->parent) ||
                    (sci_rnc->destination_state == RNC_DEST_FINAL))
                    sci_change_state(&sci_rnc->sm,
                             SCI_RNC_INVALIDATING);
                else
                    sci_change_state(&sci_rnc->sm,
                             SCI_RNC_RESUMING);
            }
        }
        return SCI_SUCCESS;

    case SCI_RNC_AWAIT_SUSPENSION:
        sci_remote_node_context_setup_to_resume(
            sci_rnc, cb_fn, cb_p, RNC_DEST_SUSPENDED_RESUME);
        return SCI_SUCCESS;
    default:
        dev_warn(scirdev_to_dev(rnc_to_dev(sci_rnc)),
             "%s: invalid state %s\n", __func__,
             rnc_state_name(state));
        return SCI_FAILURE_INVALID_STATE;
    }
}

enum sci_status sci_remote_node_context_start_io(struct sci_remote_node_context *sci_rnc,
                                 struct isci_request *ireq)
{
    enum scis_sds_remote_node_context_states state;

    state = sci_rnc->sm.current_state_id;

    switch (state) {
    case SCI_RNC_READY:
        return SCI_SUCCESS;
    case SCI_RNC_TX_SUSPENDED:
    case SCI_RNC_TX_RX_SUSPENDED:
    case SCI_RNC_AWAIT_SUSPENSION:
        dev_warn(scirdev_to_dev(rnc_to_dev(sci_rnc)),
             "%s: invalid state %s\n", __func__,
             rnc_state_name(state));
        return SCI_FAILURE_REMOTE_DEVICE_RESET_REQUIRED;
    default:
        dev_dbg(scirdev_to_dev(rnc_to_dev(sci_rnc)),
            "%s: invalid state %s\n", __func__,
            rnc_state_name(state));
        return SCI_FAILURE_INVALID_STATE;
    }
}

enum sci_status sci_remote_node_context_start_task(
    struct sci_remote_node_context *sci_rnc,
    struct isci_request *ireq,
    scics_sds_remote_node_context_callback cb_fn,
    void *cb_p)
{
    enum sci_status status = sci_remote_node_context_resume(sci_rnc,
                                cb_fn, cb_p);
    if (status != SCI_SUCCESS)
        dev_warn(scirdev_to_dev(rnc_to_dev(sci_rnc)),
            "%s: resume failed: %d\n", __func__, status);
    return status;
}

int sci_remote_node_context_is_safe_to_abort(
    struct sci_remote_node_context *sci_rnc)
{
    enum scis_sds_remote_node_context_states state;

    state = sci_rnc->sm.current_state_id;
    switch (state) {
    case SCI_RNC_INVALIDATING:
    case SCI_RNC_TX_RX_SUSPENDED:
        return 1;
    case SCI_RNC_POSTING:
    case SCI_RNC_RESUMING:
    case SCI_RNC_READY:
    case SCI_RNC_TX_SUSPENDED:
    case SCI_RNC_AWAIT_SUSPENSION:
    case SCI_RNC_INITIAL:
        return 0;
    default:
        dev_warn(scirdev_to_dev(rnc_to_dev(sci_rnc)),
             "%s: invalid state %d\n", __func__, state);
        return 0;
    }
}