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path: root/drivers/scsi/isci/remote_node_context.c
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Diffstat (limited to 'drivers/scsi/isci/remote_node_context.c')
-rw-r--r--drivers/scsi/isci/remote_node_context.c627
1 files changed, 627 insertions, 0 deletions
diff --git a/drivers/scsi/isci/remote_node_context.c b/drivers/scsi/isci/remote_node_context.c
new file mode 100644
index 000000000000..748e8339d1ec
--- /dev/null
+++ b/drivers/scsi/isci/remote_node_context.c
@@ -0,0 +1,627 @@
+/*
+ * 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 "host.h"
+#include "isci.h"
+#include "remote_device.h"
+#include "remote_node_context.h"
+#include "scu_event_codes.h"
+#include "scu_task_context.h"
+
+
+/**
+ *
+ * @sci_rnc: The RNC for which the is posted request is being made.
+ *
+ * This method will return true if the RNC is not in the initial state.  In all
+ * other states the RNC is considered active and this will return true. The
+ * destroy request of the state machine drives the RNC back to the initial
+ * state.  If the state machine changes then this routine will also have to be
+ * changed. bool true if the state machine is not in the initial state false if
+ * the state machine is in the initial state
+ */
+
+/**
+ *
+ * @sci_rnc: The state of the remote node context object to check.
+ *
+ * This method will return true if the remote node context is in a READY state
+ * otherwise it will return false bool true if the remote node context is in
+ * the ready state. false if the remote node context is not in the ready state.
+ */
+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;
+}
+
+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->dev_type == SATA_DEV || (dev->tproto & SAS_PROTOCOL_STP)) {
+		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;
+}
+
+/**
+ *
+ * @sci_rnc:
+ * @callback:
+ * @callback_parameter:
+ *
+ * This method will setup the remote node context object so it will transition
+ * to its ready state.  If the remote node context is already setup to
+ * transition to its final state then this function does nothing. none
+ */
+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)
+{
+	if (sci_rnc->destination_state != SCIC_SDS_REMOTE_NODE_DESTINATION_STATE_FINAL) {
+		sci_rnc->destination_state = SCIC_SDS_REMOTE_NODE_DESTINATION_STATE_READY;
+		sci_rnc->user_callback     = callback;
+		sci_rnc->user_cookie       = callback_parameter;
+	}
+}
+
+static void sci_remote_node_context_setup_to_destory(
+	struct sci_remote_node_context *sci_rnc,
+	scics_sds_remote_node_context_callback callback,
+	void *callback_parameter)
+{
+	sci_rnc->destination_state = SCIC_SDS_REMOTE_NODE_DESTINATION_STATE_FINAL;
+	sci_rnc->user_callback     = callback;
+	sci_rnc->user_cookie       = callback_parameter;
+}
+
+/**
+ *
+ *
+ * This method just calls the user callback function and then resets the
+ * callback.
+ */
+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)
+{
+	if (rnc->destination_state == SCIC_SDS_REMOTE_NODE_DESTINATION_STATE_READY)
+		sci_remote_node_context_resume(rnc, rnc->user_callback,
+						    rnc->user_cookie);
+}
+
+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 (!idev->is_direct_attached &&
+	    (dev->dev_type == SATA_DEV || (dev->tproto & SAS_PROTOCOL_STP))) {
+		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 (idev->is_direct_attached)
+			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);
+
+	/* 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 = SCIC_SDS_REMOTE_NODE_DESTINATION_STATE_UNSPECIFIED;
+		sci_remote_node_context_notify_user(rnc);
+	}
+}
+
+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);
+
+	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->dev_type == SATA_DEV || (dev->tproto & SAS_PROTOCOL_STP)) &&
+	    idev->is_direct_attached)
+		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);
+
+	rnc->destination_state = SCIC_SDS_REMOTE_NODE_DESTINATION_STATE_UNSPECIFIED;
+
+	if (rnc->user_callback)
+		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);
+
+	sci_remote_node_context_continue_state_transitions(rnc);
+}
+
+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] = { },
+};
+
+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 = SCIC_SDS_REMOTE_NODE_DESTINATION_STATE_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;
+
+	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 == SCIC_SDS_REMOTE_NODE_DESTINATION_STATE_FINAL)
+				state = SCI_RNC_INITIAL;
+			else
+				state = SCI_RNC_POSTING;
+			sci_change_state(&sci_rnc->sm, 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_dbg(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_dbg(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->suspension_code = scu_get_event_specifier(event_code);
+			break;
+		case SCU_EVENT_TL_RNC_SUSPEND_TX_RX:
+			sci_change_state(&sci_rnc->sm, SCI_RNC_TX_RX_SUSPENDED);
+			sci_rnc->suspension_code = scu_get_event_specifier(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:
+			sci_change_state(&sci_rnc->sm, SCI_RNC_TX_SUSPENDED);
+			sci_rnc->suspension_code = scu_get_event_specifier(event_code);
+			break;
+		case SCU_EVENT_TL_RNC_SUSPEND_TX_RX:
+			sci_change_state(&sci_rnc->sm, SCI_RNC_TX_RX_SUSPENDED);
+			sci_rnc->suspension_code = scu_get_event_specifier(event_code);
+			break;
+		default:
+			goto out;
+		}
+		break;
+	default:
+		dev_warn(scirdev_to_dev(rnc_to_dev(sci_rnc)),
+			 "%s: invalid state %d\n", __func__, state);
+		return SCI_FAILURE_INVALID_STATE;
+	}
+	return SCI_SUCCESS;
+
+ out:
+	dev_warn(scirdev_to_dev(rnc_to_dev(sci_rnc)),
+		 "%s: code: %#x state: %d\n", __func__, event_code, 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_destory(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:
+	case SCI_RNC_AWAIT_SUSPENSION:
+		sci_remote_node_context_setup_to_destory(sci_rnc, cb_fn, cb_p);
+		sci_change_state(&sci_rnc->sm, SCI_RNC_INVALIDATING);
+		return SCI_SUCCESS;
+	case SCI_RNC_INITIAL:
+		dev_warn(scirdev_to_dev(rnc_to_dev(sci_rnc)),
+			 "%s: invalid state %d\n", __func__, 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 %d\n", __func__, state);
+		return SCI_FAILURE_INVALID_STATE;
+	}
+}
+
+enum sci_status sci_remote_node_context_suspend(struct sci_remote_node_context *sci_rnc,
+						     u32 suspend_type,
+						     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;
+	if (state != SCI_RNC_READY) {
+		dev_warn(scirdev_to_dev(rnc_to_dev(sci_rnc)),
+			 "%s: invalid state %d\n", __func__, state);
+		return SCI_FAILURE_INVALID_STATE;
+	}
+
+	sci_rnc->user_callback   = cb_fn;
+	sci_rnc->user_cookie     = cb_p;
+	sci_rnc->suspension_code = suspend_type;
+
+	if (suspend_type == SCI_SOFTWARE_SUSPENSION) {
+		sci_remote_device_post_request(rnc_to_dev(sci_rnc),
+						    SCU_CONTEXT_COMMAND_POST_RNC_SUSPEND_TX);
+	}
+
+	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;
+
+	state = sci_rnc->sm.current_state_id;
+	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);
+		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:
+		if (sci_rnc->destination_state != SCIC_SDS_REMOTE_NODE_DESTINATION_STATE_READY)
+			return SCI_FAILURE_INVALID_STATE;
+
+		sci_rnc->user_callback = cb_fn;
+		sci_rnc->user_cookie   = cb_p;
+		return SCI_SUCCESS;
+	case SCI_RNC_TX_SUSPENDED: {
+		struct isci_remote_device *idev = rnc_to_dev(sci_rnc);
+		struct domain_device *dev = idev->domain_dev;
+
+		sci_remote_node_context_setup_to_resume(sci_rnc, cb_fn, cb_p);
+
+		/* TODO: consider adding a resume action of NONE, INVALIDATE, WRITE_TLCR */
+		if (dev->dev_type == SAS_END_DEV || dev_is_expander(dev))
+			sci_change_state(&sci_rnc->sm, SCI_RNC_RESUMING);
+		else if (dev->dev_type == SATA_DEV || (dev->tproto & SAS_PROTOCOL_STP)) {
+			if (idev->is_direct_attached) {
+				/* @todo Fix this since I am being silly in writing to the STPTLDARNI register. */
+				sci_change_state(&sci_rnc->sm, SCI_RNC_RESUMING);
+			} else {
+				sci_change_state(&sci_rnc->sm, SCI_RNC_INVALIDATING);
+			}
+		} else
+			return SCI_FAILURE;
+		return SCI_SUCCESS;
+	}
+	case SCI_RNC_TX_RX_SUSPENDED:
+		sci_remote_node_context_setup_to_resume(sci_rnc, cb_fn, cb_p);
+		sci_change_state(&sci_rnc->sm, SCI_RNC_RESUMING);
+		return SCI_FAILURE_INVALID_STATE;
+	case SCI_RNC_AWAIT_SUSPENSION:
+		sci_remote_node_context_setup_to_resume(sci_rnc, cb_fn, cb_p);
+		return SCI_SUCCESS;
+	default:
+		dev_warn(scirdev_to_dev(rnc_to_dev(sci_rnc)),
+			 "%s: invalid state %d\n", __func__, 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 %d\n", __func__, state);
+		return SCI_FAILURE_REMOTE_DEVICE_RESET_REQUIRED;
+	default:
+		break;
+	}
+	dev_dbg(scirdev_to_dev(rnc_to_dev(sci_rnc)),
+		"%s: requested to start IO while still resuming, %d\n",
+		__func__, 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)
+{
+	enum scis_sds_remote_node_context_states state;
+
+	state = sci_rnc->sm.current_state_id;
+	switch (state) {
+	case SCI_RNC_RESUMING:
+	case SCI_RNC_READY:
+	case SCI_RNC_AWAIT_SUSPENSION:
+		return SCI_SUCCESS;
+	case SCI_RNC_TX_SUSPENDED:
+	case SCI_RNC_TX_RX_SUSPENDED:
+		sci_remote_node_context_resume(sci_rnc, NULL, NULL);
+		return SCI_SUCCESS;
+	default:
+		dev_warn(scirdev_to_dev(rnc_to_dev(sci_rnc)),
+			 "%s: invalid state %d\n", __func__, state);
+		return SCI_FAILURE_INVALID_STATE;
+	}
+}