Merge tag 'isci-for-3.5' into misc

isci update for 3.5

1/ Rework remote-node-context (RNC) handling for proper management of
   the silicon state machine in error handling and hot-plug conditions.
   Further details below, suffice to say if the RNC is mismanaged the
   silicon state machines may lock up.

2/ Refactor the initialization code to be reused for suspend/resume support

3/ Miscellaneous bug fixes to address discovery issues and hardware
   compatibility.

RNC rework details from Jeff Skirvin:

In the controller, devices as they appear on a SAS domain (or
direct-attached SATA devices) are represented by memory structures known
as "Remote Node Contexts" (RNCs).  These structures are transferred from
main memory to the controller using a set of register commands; these
commands include setting up the context ("posting"), removing the
context ("invalidating"), and commands to control the scheduling of
commands and connections to that remote device ("suspensions" and
"resumptions").  There is a similar path to control RNC scheduling from
the protocol engine, which interprets the results of command and data
transmission and reception.

In general, the controller chooses among non-suspended RNCs to find one
that has work requiring scheduling the transmission of command and data
frames to a target.  Likewise, when a target tries to return data back
to the initiator, the state of the RNC is used by the controller to
determine how to treat the incoming request. As an example, if the RNC
is in the state "TX/RX Suspended", incoming SSP connection requests from
the target will be rejected by the controller hardware.  When an RNC is
"TX Suspended", it will not be selected by the controller hardware to
start outgoing command or data operations (with certain priority-based
exceptions).

As mentioned above, there are two sources for management of the RNC
states: commands from driver software, and the result of transmission
and reception conditions of commands and data signaled by the controller
hardware.  As an example of the latter, if an outgoing SSP command ends
with a OPEN_REJECT(BAD_DESTINATION) status, the RNC state will
transition to the "TX Suspended" state, and this is signaled by the
controller hardware in the status to the completion of the pending
command as well as signaled in a controller hardware event.  Examples of
the former are included in the patch changelogs.

Driver software is required to suspend the RNC in a "TX/RX Suspended"
condition before any outstanding commands can be terminated.  Failure to
guarantee this can lead to a complete hardware hang condition.  Earlier
versions of the driver software did not guarantee that an RNC was
correctly managed before I/O termination, and so operated in an unsafe
way.

Further, the driver performed unnecessary contortions to preserve the
remote device command state and so was more complicated than it needed
to be.  A simplifying driver assumption is that once an I/O has entered
the error handler path without having completed in the target, the
requirement on the driver is that all use of the sas_task must end.
Beyond that, recovery of operation is dependent on libsas and other
components to reset, rediscover and reconfigure the device before normal
operation can restart.  In the driver, this simplifying assumption meant
that the RNC management could be reduced to entry into the suspended
state, terminating the targeted I/O request, and resuming the RNC as
needed for device-specific management such as an SSP Abort Task or LUN
Reset Management request.

1 files changed, 289 insertions, 104 deletions

diff --git a/drivers/scsi/isci/remote_node_context.c b/drivers/scsi/isci/remote_node_context.c
index 3a9463481f38..1910100638a2 100644
--- a/drivers/scsi/isci/remote_node_context.c
+++ b/drivers/scsi/isci/remote_node_context.c
@@ -52,7 +52,7 @@
  * (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"
@@ -90,6 +90,15 @@ bool sci_remote_node_context_is_ready(
 	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 &&
@@ -131,7 +140,7 @@ static void sci_remote_node_context_construct_buffer(struct sci_remote_node_cont
 
 	rnc->ssp.arbitration_wait_time = 0;
 
-	if (dev->dev_type == SATA_DEV || (dev->tproto & SAS_PROTOCOL_STP)) {
+	if (dev_is_sata(dev)) {
 		rnc->ssp.connection_occupancy_timeout =
 			ihost->user_parameters.stp_max_occupancy_timeout;
 		rnc->ssp.connection_inactivity_timeout =
@@ -151,7 +160,6 @@ static void sci_remote_node_context_construct_buffer(struct sci_remote_node_cont
 	rnc->ssp.oaf_source_zone_group = 0;
 	rnc->ssp.oaf_more_compatibility_features = 0;
 }
-
 /**
  *
  * @sci_rnc:
@@ -165,23 +173,30 @@ static void sci_remote_node_context_construct_buffer(struct sci_remote_node_cont
 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)
+	void *callback_parameter,
+	enum sci_remote_node_context_destination_state dest_param)
 {
-	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;
+	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_destory(
+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)
 {
-	sci_rnc->destination_state = SCIC_SDS_REMOTE_NODE_DESTINATION_STATE_FINAL;
+	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);
 }
 
 /**
@@ -203,9 +218,19 @@ static void sci_remote_node_context_notify_user(
 
 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)
+	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);
+					       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)
@@ -219,13 +244,12 @@ static void sci_remote_node_context_validate_context_buffer(struct sci_remote_no
 
 	rnc_buffer->ssp.is_valid = true;
 
-	if (!idev->is_direct_attached &&
-	    (dev->dev_type == SATA_DEV || (dev->tproto & SAS_PROTOCOL_STP))) {
+	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 (idev->is_direct_attached)
+		if (!dev->parent)
 			sci_port_setup_transports(idev->owning_port,
 						  sci_rnc->remote_node_index);
 	}
@@ -248,13 +272,18 @@ static void sci_remote_node_context_invalidate_context_buffer(struct sci_remote_
 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 = SCIC_SDS_REMOTE_NODE_DESTINATION_STATE_UNSPECIFIED;
+		rnc->destination_state = RNC_DEST_UNSPECIFIED;
 		sci_remote_node_context_notify_user(rnc);
+
+		smp_wmb();
+		wake_up(&ihost->eventq);
 	}
 }
 
@@ -269,6 +298,8 @@ static void sci_remote_node_context_invalidating_state_enter(struct sci_base_sta
 {
 	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);
 }
 
@@ -287,10 +318,8 @@ static void sci_remote_node_context_resuming_state_enter(struct sci_base_state_m
 	 * 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);
+	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);
 }
@@ -298,10 +327,22 @@ static void sci_remote_node_context_resuming_state_enter(struct sci_base_state_m
 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;
 
-	rnc->destination_state = SCIC_SDS_REMOTE_NODE_DESTINATION_STATE_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 (rnc->user_callback)
+		if (dest_select == RNC_DEST_SUSPENDED_RESUME)
+			tell_user = 0;  /* Wait until ready again. */
+	}
+	if (tell_user)
 		sci_remote_node_context_notify_user(rnc);
 }
 
@@ -315,10 +356,34 @@ static void sci_remote_node_context_tx_suspended_state_enter(struct sci_base_sta
 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,
@@ -341,7 +406,9 @@ static const struct sci_base_state sci_remote_node_context_state_table[] = {
 	[SCI_RNC_TX_RX_SUSPENDED] = {
 		.enter_state = sci_remote_node_context_tx_rx_suspended_state_enter,
 	},
-	[SCI_RNC_AWAIT_SUSPENSION] = { },
+	[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,
@@ -350,7 +417,7 @@ void sci_remote_node_context_construct(struct sci_remote_node_context *rnc,
 	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;
+	rnc->destination_state = RNC_DEST_UNSPECIFIED;
 
 	sci_init_sm(&rnc->sm, sci_remote_node_context_state_table, SCI_RNC_INITIAL);
 }
@@ -359,6 +426,7 @@ enum sci_status sci_remote_node_context_event_handler(struct sci_remote_node_con
 							   u32 event_code)
 {
 	enum scis_sds_remote_node_context_states state;
+	u32 next_state;
 
 	state = sci_rnc->sm.current_state_id;
 	switch (state) {
@@ -373,18 +441,18 @@ enum sci_status sci_remote_node_context_event_handler(struct sci_remote_node_con
 		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;
+			if (sci_rnc->destination_state == RNC_DEST_FINAL)
+				next_state = SCI_RNC_INITIAL;
 			else
-				state = SCI_RNC_POSTING;
-			sci_change_state(&sci_rnc->sm, state);
+				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_dbg(scirdev_to_dev(rnc_to_dev(sci_rnc)),
+				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);
@@ -403,7 +471,7 @@ enum sci_status sci_remote_node_context_event_handler(struct sci_remote_node_con
 			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)),
+				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);
@@ -417,11 +485,11 @@ enum sci_status sci_remote_node_context_event_handler(struct sci_remote_node_con
 		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);
+			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->suspension_code = scu_get_event_specifier(event_code);
+			sci_rnc->suspend_type = scu_get_event_type(event_code);
 			break;
 		default:
 			goto out;
@@ -430,27 +498,29 @@ enum sci_status sci_remote_node_context_event_handler(struct sci_remote_node_con
 	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);
+			next_state = SCI_RNC_TX_SUSPENDED;
 			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);
+			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 %d\n", __func__, state);
+			 "%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: %d\n", __func__, event_code, state);
+		 "%s: code: %#x state: %s\n", __func__, event_code,
+		 rnc_state_name(state));
 	return SCI_FAILURE;
 
 }
@@ -464,20 +534,23 @@ enum sci_status sci_remote_node_context_destruct(struct sci_remote_node_context
 	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);
+		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:
-	case SCI_RNC_AWAIT_SUSPENSION:
-		sci_remote_node_context_setup_to_destory(sci_rnc, cb_fn, cb_p);
+		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 %d\n", __func__, state);
+			 "%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.
@@ -485,35 +558,101 @@ enum sci_status sci_remote_node_context_destruct(struct sci_remote_node_context
 		return SCI_SUCCESS;
 	default:
 		dev_warn(scirdev_to_dev(rnc_to_dev(sci_rnc)),
-			 "%s: invalid state %d\n", __func__, state);
+			 "%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,
-						     u32 suspend_type,
-						     scics_sds_remote_node_context_callback cb_fn,
-						     void *cb_p)
+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;
+	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;
 
-	state = sci_rnc->sm.current_state_id;
-	if (state != SCI_RNC_READY) {
+	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 %d\n", __func__, state);
+			 "%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)) {
 
-	sci_rnc->user_callback   = cb_fn;
-	sci_rnc->user_cookie     = cb_p;
-	sci_rnc->suspension_code = suspend_type;
+		if (suspend_reason == SCI_SW_SUSPEND_LINKHANG_DETECT)
+			isci_dev_set_hang_detection_timeout(idev, 0x00000001);
 
-	if (suspend_type == SCI_SOFTWARE_SUSPENSION) {
-		sci_remote_device_post_request(rnc_to_dev(sci_rnc),
-						    SCU_CONTEXT_COMMAND_POST_RNC_SUSPEND_TX);
+		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);
 
-	sci_change_state(&sci_rnc->sm, SCI_RNC_AWAIT_SUSPENSION);
 	return SCI_SUCCESS;
 }
 
@@ -522,56 +661,86 @@ enum sci_status sci_remote_node_context_resume(struct sci_remote_node_context *s
 						    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);
-		sci_remote_node_context_construct_buffer(sci_rnc);
-		sci_change_state(&sci_rnc->sm, SCI_RNC_POSTING);
+		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:
-		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;
+		/* 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: {
-		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);
+
+	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);
 			}
-		} 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);
+		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 %d\n", __func__, state);
+			 "%s: invalid state %s\n", __func__,
+			 rnc_state_name(state));
 		return SCI_FAILURE_INVALID_STATE;
 	}
 }
@@ -590,35 +759,51 @@ enum sci_status sci_remote_node_context_start_io(struct sci_remote_node_context
 	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);
+			 "%s: invalid state %s\n", __func__,
+			 rnc_state_name(state));
 		return SCI_FAILURE_REMOTE_DEVICE_RESET_REQUIRED;
 	default:
-		break;
+		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;
 	}
-	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 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_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;
+	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 SCI_FAILURE_INVALID_STATE;
+		return 0;
 	}
 }