1 /*
2  * This file is provided under a dual BSD/GPLv2 license.  When using or
3  * redistributing this file, you may do so under either license.
4  *
5  * GPL LICENSE SUMMARY
6  *
7  * Copyright(c) 2008 - 2011 Intel Corporation. All rights reserved.
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of version 2 of the GNU General Public License as
11  * published by the Free Software Foundation.
12  *
13  * This program is distributed in the hope that it will be useful, but
14  * WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16  * General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
21  * The full GNU General Public License is included in this distribution
22  * in the file called LICENSE.GPL.
23  *
24  * BSD LICENSE
25  *
26  * Copyright(c) 2008 - 2011 Intel Corporation. All rights reserved.
27  * All rights reserved.
28  *
29  * Redistribution and use in source and binary forms, with or without
30  * modification, are permitted provided that the following conditions
31  * are met:
32  *
33  *   * Redistributions of source code must retain the above copyright
34  *     notice, this list of conditions and the following disclaimer.
35  *   * Redistributions in binary form must reproduce the above copyright
36  *     notice, this list of conditions and the following disclaimer in
37  *     the documentation and/or other materials provided with the
38  *     distribution.
39  *   * Neither the name of Intel Corporation nor the names of its
40  *     contributors may be used to endorse or promote products derived
41  *     from this software without specific prior written permission.
42  *
43  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
44  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
45  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
46  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
47  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
48  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
49  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
50  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
51  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
52  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
53  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
54  */
55 
56 #include "host.h"
57 #include "isci.h"
58 #include "remote_device.h"
59 #include "remote_node_context.h"
60 #include "scu_event_codes.h"
61 #include "scu_task_context.h"
62 
63 
64 /**
65  *
66  * @sci_rnc: The RNC for which the is posted request is being made.
67  *
68  * This method will return true if the RNC is not in the initial state.  In all
69  * other states the RNC is considered active and this will return true. The
70  * destroy request of the state machine drives the RNC back to the initial
71  * state.  If the state machine changes then this routine will also have to be
72  * changed. bool true if the state machine is not in the initial state false if
73  * the state machine is in the initial state
74  */
75 
76 /**
77  *
78  * @sci_rnc: The state of the remote node context object to check.
79  *
80  * This method will return true if the remote node context is in a READY state
81  * otherwise it will return false bool true if the remote node context is in
82  * the ready state. false if the remote node context is not in the ready state.
83  */
84 bool sci_remote_node_context_is_ready(
85 	struct sci_remote_node_context *sci_rnc)
86 {
87 	u32 current_state = sci_rnc->sm.current_state_id;
88 
89 	if (current_state == SCI_RNC_READY) {
90 		return true;
91 	}
92 
93 	return false;
94 }
95 
96 static union scu_remote_node_context *sci_rnc_by_id(struct isci_host *ihost, u16 id)
97 {
98 	if (id < ihost->remote_node_entries &&
99 	    ihost->device_table[id])
100 		return &ihost->remote_node_context_table[id];
101 
102 	return NULL;
103 }
104 
105 static void sci_remote_node_context_construct_buffer(struct sci_remote_node_context *sci_rnc)
106 {
107 	struct isci_remote_device *idev = rnc_to_dev(sci_rnc);
108 	struct domain_device *dev = idev->domain_dev;
109 	int rni = sci_rnc->remote_node_index;
110 	union scu_remote_node_context *rnc;
111 	struct isci_host *ihost;
112 	__le64 sas_addr;
113 
114 	ihost = idev->owning_port->owning_controller;
115 	rnc = sci_rnc_by_id(ihost, rni);
116 
117 	memset(rnc, 0, sizeof(union scu_remote_node_context)
118 		* sci_remote_device_node_count(idev));
119 
120 	rnc->ssp.remote_node_index = rni;
121 	rnc->ssp.remote_node_port_width = idev->device_port_width;
122 	rnc->ssp.logical_port_index = idev->owning_port->physical_port_index;
123 
124 	/* sas address is __be64, context ram format is __le64 */
125 	sas_addr = cpu_to_le64(SAS_ADDR(dev->sas_addr));
126 	rnc->ssp.remote_sas_address_hi = upper_32_bits(sas_addr);
127 	rnc->ssp.remote_sas_address_lo = lower_32_bits(sas_addr);
128 
129 	rnc->ssp.nexus_loss_timer_enable = true;
130 	rnc->ssp.check_bit               = false;
131 	rnc->ssp.is_valid                = false;
132 	rnc->ssp.is_remote_node_context  = true;
133 	rnc->ssp.function_number         = 0;
134 
135 	rnc->ssp.arbitration_wait_time = 0;
136 
137 	if (dev->dev_type == SATA_DEV || (dev->tproto & SAS_PROTOCOL_STP)) {
138 		rnc->ssp.connection_occupancy_timeout =
139 			ihost->user_parameters.stp_max_occupancy_timeout;
140 		rnc->ssp.connection_inactivity_timeout =
141 			ihost->user_parameters.stp_inactivity_timeout;
142 	} else {
143 		rnc->ssp.connection_occupancy_timeout  =
144 			ihost->user_parameters.ssp_max_occupancy_timeout;
145 		rnc->ssp.connection_inactivity_timeout =
146 			ihost->user_parameters.ssp_inactivity_timeout;
147 	}
148 
149 	rnc->ssp.initial_arbitration_wait_time = 0;
150 
151 	/* Open Address Frame Parameters */
152 	rnc->ssp.oaf_connection_rate = idev->connection_rate;
153 	rnc->ssp.oaf_features = 0;
154 	rnc->ssp.oaf_source_zone_group = 0;
155 	rnc->ssp.oaf_more_compatibility_features = 0;
156 }
157 
158 /**
159  *
160  * @sci_rnc:
161  * @callback:
162  * @callback_parameter:
163  *
164  * This method will setup the remote node context object so it will transition
165  * to its ready state.  If the remote node context is already setup to
166  * transition to its final state then this function does nothing. none
167  */
168 static void sci_remote_node_context_setup_to_resume(
169 	struct sci_remote_node_context *sci_rnc,
170 	scics_sds_remote_node_context_callback callback,
171 	void *callback_parameter)
172 {
173 	if (sci_rnc->destination_state != SCIC_SDS_REMOTE_NODE_DESTINATION_STATE_FINAL) {
174 		sci_rnc->destination_state = SCIC_SDS_REMOTE_NODE_DESTINATION_STATE_READY;
175 		sci_rnc->user_callback     = callback;
176 		sci_rnc->user_cookie       = callback_parameter;
177 	}
178 }
179 
180 static void sci_remote_node_context_setup_to_destory(
181 	struct sci_remote_node_context *sci_rnc,
182 	scics_sds_remote_node_context_callback callback,
183 	void *callback_parameter)
184 {
185 	sci_rnc->destination_state = SCIC_SDS_REMOTE_NODE_DESTINATION_STATE_FINAL;
186 	sci_rnc->user_callback     = callback;
187 	sci_rnc->user_cookie       = callback_parameter;
188 }
189 
190 /**
191  *
192  *
193  * This method just calls the user callback function and then resets the
194  * callback.
195  */
196 static void sci_remote_node_context_notify_user(
197 	struct sci_remote_node_context *rnc)
198 {
199 	if (rnc->user_callback != NULL) {
200 		(*rnc->user_callback)(rnc->user_cookie);
201 
202 		rnc->user_callback = NULL;
203 		rnc->user_cookie = NULL;
204 	}
205 }
206 
207 static void sci_remote_node_context_continue_state_transitions(struct sci_remote_node_context *rnc)
208 {
209 	if (rnc->destination_state == SCIC_SDS_REMOTE_NODE_DESTINATION_STATE_READY)
210 		sci_remote_node_context_resume(rnc, rnc->user_callback,
211 						    rnc->user_cookie);
212 }
213 
214 static void sci_remote_node_context_validate_context_buffer(struct sci_remote_node_context *sci_rnc)
215 {
216 	union scu_remote_node_context *rnc_buffer;
217 	struct isci_remote_device *idev = rnc_to_dev(sci_rnc);
218 	struct domain_device *dev = idev->domain_dev;
219 	struct isci_host *ihost = idev->owning_port->owning_controller;
220 
221 	rnc_buffer = sci_rnc_by_id(ihost, sci_rnc->remote_node_index);
222 
223 	rnc_buffer->ssp.is_valid = true;
224 
225 	if (!idev->is_direct_attached &&
226 	    (dev->dev_type == SATA_DEV || (dev->tproto & SAS_PROTOCOL_STP))) {
227 		sci_remote_device_post_request(idev, SCU_CONTEXT_COMMAND_POST_RNC_96);
228 	} else {
229 		sci_remote_device_post_request(idev, SCU_CONTEXT_COMMAND_POST_RNC_32);
230 
231 		if (idev->is_direct_attached)
232 			sci_port_setup_transports(idev->owning_port,
233 						  sci_rnc->remote_node_index);
234 	}
235 }
236 
237 static void sci_remote_node_context_invalidate_context_buffer(struct sci_remote_node_context *sci_rnc)
238 {
239 	union scu_remote_node_context *rnc_buffer;
240 	struct isci_remote_device *idev = rnc_to_dev(sci_rnc);
241 	struct isci_host *ihost = idev->owning_port->owning_controller;
242 
243 	rnc_buffer = sci_rnc_by_id(ihost, sci_rnc->remote_node_index);
244 
245 	rnc_buffer->ssp.is_valid = false;
246 
247 	sci_remote_device_post_request(rnc_to_dev(sci_rnc),
248 				       SCU_CONTEXT_COMMAND_POST_RNC_INVALIDATE);
249 }
250 
251 static void sci_remote_node_context_initial_state_enter(struct sci_base_state_machine *sm)
252 {
253 	struct sci_remote_node_context *rnc = container_of(sm, typeof(*rnc), sm);
254 
255 	/* Check to see if we have gotten back to the initial state because
256 	 * someone requested to destroy the remote node context object.
257 	 */
258 	if (sm->previous_state_id == SCI_RNC_INVALIDATING) {
259 		rnc->destination_state = SCIC_SDS_REMOTE_NODE_DESTINATION_STATE_UNSPECIFIED;
260 		sci_remote_node_context_notify_user(rnc);
261 	}
262 }
263 
264 static void sci_remote_node_context_posting_state_enter(struct sci_base_state_machine *sm)
265 {
266 	struct sci_remote_node_context *sci_rnc = container_of(sm, typeof(*sci_rnc), sm);
267 
268 	sci_remote_node_context_validate_context_buffer(sci_rnc);
269 }
270 
271 static void sci_remote_node_context_invalidating_state_enter(struct sci_base_state_machine *sm)
272 {
273 	struct sci_remote_node_context *rnc = container_of(sm, typeof(*rnc), sm);
274 
275 	sci_remote_node_context_invalidate_context_buffer(rnc);
276 }
277 
278 static void sci_remote_node_context_resuming_state_enter(struct sci_base_state_machine *sm)
279 {
280 	struct sci_remote_node_context *rnc = container_of(sm, typeof(*rnc), sm);
281 	struct isci_remote_device *idev;
282 	struct domain_device *dev;
283 
284 	idev = rnc_to_dev(rnc);
285 	dev = idev->domain_dev;
286 
287 	/*
288 	 * For direct attached SATA devices we need to clear the TLCR
289 	 * NCQ to TCi tag mapping on the phy and in cases where we
290 	 * resume because of a target reset we also need to update
291 	 * the STPTLDARNI register with the RNi of the device
292 	 */
293 	if ((dev->dev_type == SATA_DEV || (dev->tproto & SAS_PROTOCOL_STP)) &&
294 	    idev->is_direct_attached)
295 		sci_port_setup_transports(idev->owning_port,
296 					       rnc->remote_node_index);
297 
298 	sci_remote_device_post_request(idev, SCU_CONTEXT_COMMAND_POST_RNC_RESUME);
299 }
300 
301 static void sci_remote_node_context_ready_state_enter(struct sci_base_state_machine *sm)
302 {
303 	struct sci_remote_node_context *rnc = container_of(sm, typeof(*rnc), sm);
304 
305 	rnc->destination_state = SCIC_SDS_REMOTE_NODE_DESTINATION_STATE_UNSPECIFIED;
306 
307 	if (rnc->user_callback)
308 		sci_remote_node_context_notify_user(rnc);
309 }
310 
311 static void sci_remote_node_context_tx_suspended_state_enter(struct sci_base_state_machine *sm)
312 {
313 	struct sci_remote_node_context *rnc = container_of(sm, typeof(*rnc), sm);
314 
315 	sci_remote_node_context_continue_state_transitions(rnc);
316 }
317 
318 static void sci_remote_node_context_tx_rx_suspended_state_enter(struct sci_base_state_machine *sm)
319 {
320 	struct sci_remote_node_context *rnc = container_of(sm, typeof(*rnc), sm);
321 
322 	sci_remote_node_context_continue_state_transitions(rnc);
323 }
324 
325 static const struct sci_base_state sci_remote_node_context_state_table[] = {
326 	[SCI_RNC_INITIAL] = {
327 		.enter_state = sci_remote_node_context_initial_state_enter,
328 	},
329 	[SCI_RNC_POSTING] = {
330 		.enter_state = sci_remote_node_context_posting_state_enter,
331 	},
332 	[SCI_RNC_INVALIDATING] = {
333 		.enter_state = sci_remote_node_context_invalidating_state_enter,
334 	},
335 	[SCI_RNC_RESUMING] = {
336 		.enter_state = sci_remote_node_context_resuming_state_enter,
337 	},
338 	[SCI_RNC_READY] = {
339 		.enter_state = sci_remote_node_context_ready_state_enter,
340 	},
341 	[SCI_RNC_TX_SUSPENDED] = {
342 		.enter_state = sci_remote_node_context_tx_suspended_state_enter,
343 	},
344 	[SCI_RNC_TX_RX_SUSPENDED] = {
345 		.enter_state = sci_remote_node_context_tx_rx_suspended_state_enter,
346 	},
347 	[SCI_RNC_AWAIT_SUSPENSION] = { },
348 };
349 
350 void sci_remote_node_context_construct(struct sci_remote_node_context *rnc,
351 					    u16 remote_node_index)
352 {
353 	memset(rnc, 0, sizeof(struct sci_remote_node_context));
354 
355 	rnc->remote_node_index = remote_node_index;
356 	rnc->destination_state = SCIC_SDS_REMOTE_NODE_DESTINATION_STATE_UNSPECIFIED;
357 
358 	sci_init_sm(&rnc->sm, sci_remote_node_context_state_table, SCI_RNC_INITIAL);
359 }
360 
361 enum sci_status sci_remote_node_context_event_handler(struct sci_remote_node_context *sci_rnc,
362 							   u32 event_code)
363 {
364 	enum scis_sds_remote_node_context_states state;
365 
366 	state = sci_rnc->sm.current_state_id;
367 	switch (state) {
368 	case SCI_RNC_POSTING:
369 		switch (scu_get_event_code(event_code)) {
370 		case SCU_EVENT_POST_RNC_COMPLETE:
371 			sci_change_state(&sci_rnc->sm, SCI_RNC_READY);
372 			break;
373 		default:
374 			goto out;
375 		}
376 		break;
377 	case SCI_RNC_INVALIDATING:
378 		if (scu_get_event_code(event_code) == SCU_EVENT_POST_RNC_INVALIDATE_COMPLETE) {
379 			if (sci_rnc->destination_state == SCIC_SDS_REMOTE_NODE_DESTINATION_STATE_FINAL)
380 				state = SCI_RNC_INITIAL;
381 			else
382 				state = SCI_RNC_POSTING;
383 			sci_change_state(&sci_rnc->sm, state);
384 		} else {
385 			switch (scu_get_event_type(event_code)) {
386 			case SCU_EVENT_TYPE_RNC_SUSPEND_TX:
387 			case SCU_EVENT_TYPE_RNC_SUSPEND_TX_RX:
388 				/* We really dont care if the hardware is going to suspend
389 				 * the device since it's being invalidated anyway */
390 				dev_dbg(scirdev_to_dev(rnc_to_dev(sci_rnc)),
391 					"%s: SCIC Remote Node Context 0x%p was "
392 					"suspeneded by hardware while being "
393 					"invalidated.\n", __func__, sci_rnc);
394 				break;
395 			default:
396 				goto out;
397 			}
398 		}
399 		break;
400 	case SCI_RNC_RESUMING:
401 		if (scu_get_event_code(event_code) == SCU_EVENT_POST_RCN_RELEASE) {
402 			sci_change_state(&sci_rnc->sm, SCI_RNC_READY);
403 		} else {
404 			switch (scu_get_event_type(event_code)) {
405 			case SCU_EVENT_TYPE_RNC_SUSPEND_TX:
406 			case SCU_EVENT_TYPE_RNC_SUSPEND_TX_RX:
407 				/* We really dont care if the hardware is going to suspend
408 				 * the device since it's being resumed anyway */
409 				dev_dbg(scirdev_to_dev(rnc_to_dev(sci_rnc)),
410 					"%s: SCIC Remote Node Context 0x%p was "
411 					"suspeneded by hardware while being resumed.\n",
412 					__func__, sci_rnc);
413 				break;
414 			default:
415 				goto out;
416 			}
417 		}
418 		break;
419 	case SCI_RNC_READY:
420 		switch (scu_get_event_type(event_code)) {
421 		case SCU_EVENT_TL_RNC_SUSPEND_TX:
422 			sci_change_state(&sci_rnc->sm, SCI_RNC_TX_SUSPENDED);
423 			sci_rnc->suspension_code = scu_get_event_specifier(event_code);
424 			break;
425 		case SCU_EVENT_TL_RNC_SUSPEND_TX_RX:
426 			sci_change_state(&sci_rnc->sm, SCI_RNC_TX_RX_SUSPENDED);
427 			sci_rnc->suspension_code = scu_get_event_specifier(event_code);
428 			break;
429 		default:
430 			goto out;
431 		}
432 		break;
433 	case SCI_RNC_AWAIT_SUSPENSION:
434 		switch (scu_get_event_type(event_code)) {
435 		case SCU_EVENT_TL_RNC_SUSPEND_TX:
436 			sci_change_state(&sci_rnc->sm, SCI_RNC_TX_SUSPENDED);
437 			sci_rnc->suspension_code = scu_get_event_specifier(event_code);
438 			break;
439 		case SCU_EVENT_TL_RNC_SUSPEND_TX_RX:
440 			sci_change_state(&sci_rnc->sm, SCI_RNC_TX_RX_SUSPENDED);
441 			sci_rnc->suspension_code = scu_get_event_specifier(event_code);
442 			break;
443 		default:
444 			goto out;
445 		}
446 		break;
447 	default:
448 		dev_warn(scirdev_to_dev(rnc_to_dev(sci_rnc)),
449 			 "%s: invalid state %d\n", __func__, state);
450 		return SCI_FAILURE_INVALID_STATE;
451 	}
452 	return SCI_SUCCESS;
453 
454  out:
455 	dev_warn(scirdev_to_dev(rnc_to_dev(sci_rnc)),
456 		 "%s: code: %#x state: %d\n", __func__, event_code, state);
457 	return SCI_FAILURE;
458 
459 }
460 
461 enum sci_status sci_remote_node_context_destruct(struct sci_remote_node_context *sci_rnc,
462 						      scics_sds_remote_node_context_callback cb_fn,
463 						      void *cb_p)
464 {
465 	enum scis_sds_remote_node_context_states state;
466 
467 	state = sci_rnc->sm.current_state_id;
468 	switch (state) {
469 	case SCI_RNC_INVALIDATING:
470 		sci_remote_node_context_setup_to_destory(sci_rnc, cb_fn, cb_p);
471 		return SCI_SUCCESS;
472 	case SCI_RNC_POSTING:
473 	case SCI_RNC_RESUMING:
474 	case SCI_RNC_READY:
475 	case SCI_RNC_TX_SUSPENDED:
476 	case SCI_RNC_TX_RX_SUSPENDED:
477 	case SCI_RNC_AWAIT_SUSPENSION:
478 		sci_remote_node_context_setup_to_destory(sci_rnc, cb_fn, cb_p);
479 		sci_change_state(&sci_rnc->sm, SCI_RNC_INVALIDATING);
480 		return SCI_SUCCESS;
481 	case SCI_RNC_INITIAL:
482 		dev_warn(scirdev_to_dev(rnc_to_dev(sci_rnc)),
483 			 "%s: invalid state %d\n", __func__, state);
484 		/* We have decided that the destruct request on the remote node context
485 		 * can not fail since it is either in the initial/destroyed state or is
486 		 * can be destroyed.
487 		 */
488 		return SCI_SUCCESS;
489 	default:
490 		dev_warn(scirdev_to_dev(rnc_to_dev(sci_rnc)),
491 			 "%s: invalid state %d\n", __func__, state);
492 		return SCI_FAILURE_INVALID_STATE;
493 	}
494 }
495 
496 enum sci_status sci_remote_node_context_suspend(struct sci_remote_node_context *sci_rnc,
497 						     u32 suspend_type,
498 						     scics_sds_remote_node_context_callback cb_fn,
499 						     void *cb_p)
500 {
501 	enum scis_sds_remote_node_context_states state;
502 
503 	state = sci_rnc->sm.current_state_id;
504 	if (state != SCI_RNC_READY) {
505 		dev_warn(scirdev_to_dev(rnc_to_dev(sci_rnc)),
506 			 "%s: invalid state %d\n", __func__, state);
507 		return SCI_FAILURE_INVALID_STATE;
508 	}
509 
510 	sci_rnc->user_callback   = cb_fn;
511 	sci_rnc->user_cookie     = cb_p;
512 	sci_rnc->suspension_code = suspend_type;
513 
514 	if (suspend_type == SCI_SOFTWARE_SUSPENSION) {
515 		sci_remote_device_post_request(rnc_to_dev(sci_rnc),
516 						    SCU_CONTEXT_COMMAND_POST_RNC_SUSPEND_TX);
517 	}
518 
519 	sci_change_state(&sci_rnc->sm, SCI_RNC_AWAIT_SUSPENSION);
520 	return SCI_SUCCESS;
521 }
522 
523 enum sci_status sci_remote_node_context_resume(struct sci_remote_node_context *sci_rnc,
524 						    scics_sds_remote_node_context_callback cb_fn,
525 						    void *cb_p)
526 {
527 	enum scis_sds_remote_node_context_states state;
528 
529 	state = sci_rnc->sm.current_state_id;
530 	switch (state) {
531 	case SCI_RNC_INITIAL:
532 		if (sci_rnc->remote_node_index == SCIC_SDS_REMOTE_NODE_CONTEXT_INVALID_INDEX)
533 			return SCI_FAILURE_INVALID_STATE;
534 
535 		sci_remote_node_context_setup_to_resume(sci_rnc, cb_fn, cb_p);
536 		sci_remote_node_context_construct_buffer(sci_rnc);
537 		sci_change_state(&sci_rnc->sm, SCI_RNC_POSTING);
538 		return SCI_SUCCESS;
539 	case SCI_RNC_POSTING:
540 	case SCI_RNC_INVALIDATING:
541 	case SCI_RNC_RESUMING:
542 		if (sci_rnc->destination_state != SCIC_SDS_REMOTE_NODE_DESTINATION_STATE_READY)
543 			return SCI_FAILURE_INVALID_STATE;
544 
545 		sci_rnc->user_callback = cb_fn;
546 		sci_rnc->user_cookie   = cb_p;
547 		return SCI_SUCCESS;
548 	case SCI_RNC_TX_SUSPENDED: {
549 		struct isci_remote_device *idev = rnc_to_dev(sci_rnc);
550 		struct domain_device *dev = idev->domain_dev;
551 
552 		sci_remote_node_context_setup_to_resume(sci_rnc, cb_fn, cb_p);
553 
554 		/* TODO: consider adding a resume action of NONE, INVALIDATE, WRITE_TLCR */
555 		if (dev->dev_type == SAS_END_DEV || dev_is_expander(dev))
556 			sci_change_state(&sci_rnc->sm, SCI_RNC_RESUMING);
557 		else if (dev->dev_type == SATA_DEV || (dev->tproto & SAS_PROTOCOL_STP)) {
558 			if (idev->is_direct_attached) {
559 				/* @todo Fix this since I am being silly in writing to the STPTLDARNI register. */
560 				sci_change_state(&sci_rnc->sm, SCI_RNC_RESUMING);
561 			} else {
562 				sci_change_state(&sci_rnc->sm, SCI_RNC_INVALIDATING);
563 			}
564 		} else
565 			return SCI_FAILURE;
566 		return SCI_SUCCESS;
567 	}
568 	case SCI_RNC_TX_RX_SUSPENDED:
569 		sci_remote_node_context_setup_to_resume(sci_rnc, cb_fn, cb_p);
570 		sci_change_state(&sci_rnc->sm, SCI_RNC_RESUMING);
571 		return SCI_FAILURE_INVALID_STATE;
572 	case SCI_RNC_AWAIT_SUSPENSION:
573 		sci_remote_node_context_setup_to_resume(sci_rnc, cb_fn, cb_p);
574 		return SCI_SUCCESS;
575 	default:
576 		dev_warn(scirdev_to_dev(rnc_to_dev(sci_rnc)),
577 			 "%s: invalid state %d\n", __func__, state);
578 		return SCI_FAILURE_INVALID_STATE;
579 	}
580 }
581 
582 enum sci_status sci_remote_node_context_start_io(struct sci_remote_node_context *sci_rnc,
583 							     struct isci_request *ireq)
584 {
585 	enum scis_sds_remote_node_context_states state;
586 
587 	state = sci_rnc->sm.current_state_id;
588 
589 	switch (state) {
590 	case SCI_RNC_READY:
591 		return SCI_SUCCESS;
592 	case SCI_RNC_TX_SUSPENDED:
593 	case SCI_RNC_TX_RX_SUSPENDED:
594 	case SCI_RNC_AWAIT_SUSPENSION:
595 		dev_warn(scirdev_to_dev(rnc_to_dev(sci_rnc)),
596 			 "%s: invalid state %d\n", __func__, state);
597 		return SCI_FAILURE_REMOTE_DEVICE_RESET_REQUIRED;
598 	default:
599 		break;
600 	}
601 	dev_dbg(scirdev_to_dev(rnc_to_dev(sci_rnc)),
602 		"%s: requested to start IO while still resuming, %d\n",
603 		__func__, state);
604 	return SCI_FAILURE_INVALID_STATE;
605 }
606 
607 enum sci_status sci_remote_node_context_start_task(struct sci_remote_node_context *sci_rnc,
608 							struct isci_request *ireq)
609 {
610 	enum scis_sds_remote_node_context_states state;
611 
612 	state = sci_rnc->sm.current_state_id;
613 	switch (state) {
614 	case SCI_RNC_RESUMING:
615 	case SCI_RNC_READY:
616 	case SCI_RNC_AWAIT_SUSPENSION:
617 		return SCI_SUCCESS;
618 	case SCI_RNC_TX_SUSPENDED:
619 	case SCI_RNC_TX_RX_SUSPENDED:
620 		sci_remote_node_context_resume(sci_rnc, NULL, NULL);
621 		return SCI_SUCCESS;
622 	default:
623 		dev_warn(scirdev_to_dev(rnc_to_dev(sci_rnc)),
624 			 "%s: invalid state %d\n", __func__, state);
625 		return SCI_FAILURE_INVALID_STATE;
626 	}
627 }
628