xref: /openbmc/linux/drivers/ata/libata-eh.c (revision d8af0eb6046c56e7238171ca420622541db24926)
1 /*
2  *  libata-eh.c - libata error handling
3  *
4  *  Maintained by:  Jeff Garzik <jgarzik@pobox.com>
5  *    		    Please ALWAYS copy linux-ide@vger.kernel.org
6  *		    on emails.
7  *
8  *  Copyright 2006 Tejun Heo <htejun@gmail.com>
9  *
10  *
11  *  This program is free software; you can redistribute it and/or
12  *  modify it under the terms of the GNU General Public License as
13  *  published by the Free Software Foundation; either version 2, or
14  *  (at your option) any later version.
15  *
16  *  This program is distributed in the hope that it will be useful,
17  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
18  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
19  *  General Public License for more details.
20  *
21  *  You should have received a copy of the GNU General Public License
22  *  along with this program; see the file COPYING.  If not, write to
23  *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139,
24  *  USA.
25  *
26  *
27  *  libata documentation is available via 'make {ps|pdf}docs',
28  *  as Documentation/DocBook/libata.*
29  *
30  *  Hardware documentation available from http://www.t13.org/ and
31  *  http://www.sata-io.org/
32  *
33  */
34 
35 #include <linux/kernel.h>
36 #include <linux/pci.h>
37 #include <scsi/scsi.h>
38 #include <scsi/scsi_host.h>
39 #include <scsi/scsi_eh.h>
40 #include <scsi/scsi_device.h>
41 #include <scsi/scsi_cmnd.h>
42 #include "../scsi/scsi_transport_api.h"
43 
44 #include <linux/libata.h>
45 
46 #include "libata.h"
47 
48 enum {
49 	/* speed down verdicts */
50 	ATA_EH_SPDN_NCQ_OFF		= (1 << 0),
51 	ATA_EH_SPDN_SPEED_DOWN		= (1 << 1),
52 	ATA_EH_SPDN_FALLBACK_TO_PIO	= (1 << 2),
53 	ATA_EH_SPDN_KEEP_ERRORS		= (1 << 3),
54 
55 	/* error flags */
56 	ATA_EFLAG_IS_IO			= (1 << 0),
57 	ATA_EFLAG_DUBIOUS_XFER		= (1 << 1),
58 
59 	/* error categories */
60 	ATA_ECAT_NONE			= 0,
61 	ATA_ECAT_ATA_BUS		= 1,
62 	ATA_ECAT_TOUT_HSM		= 2,
63 	ATA_ECAT_UNK_DEV		= 3,
64 	ATA_ECAT_DUBIOUS_NONE		= 4,
65 	ATA_ECAT_DUBIOUS_ATA_BUS	= 5,
66 	ATA_ECAT_DUBIOUS_TOUT_HSM	= 6,
67 	ATA_ECAT_DUBIOUS_UNK_DEV	= 7,
68 	ATA_ECAT_NR			= 8,
69 
70 	/* always put at least this amount of time between resets */
71 	ATA_EH_RESET_COOL_DOWN		=  5000,
72 
73 	/* Waiting in ->prereset can never be reliable.  It's
74 	 * sometimes nice to wait there but it can't be depended upon;
75 	 * otherwise, we wouldn't be resetting.  Just give it enough
76 	 * time for most drives to spin up.
77 	 */
78 	ATA_EH_PRERESET_TIMEOUT		= 10000,
79 	ATA_EH_FASTDRAIN_INTERVAL	=  3000,
80 };
81 
82 /* The following table determines how we sequence resets.  Each entry
83  * represents timeout for that try.  The first try can be soft or
84  * hardreset.  All others are hardreset if available.  In most cases
85  * the first reset w/ 10sec timeout should succeed.  Following entries
86  * are mostly for error handling, hotplug and retarded devices.
87  */
88 static const unsigned long ata_eh_reset_timeouts[] = {
89 	10000,	/* most drives spin up by 10sec */
90 	10000,	/* > 99% working drives spin up before 20sec */
91 	35000,	/* give > 30 secs of idleness for retarded devices */
92 	 5000,	/* and sweet one last chance */
93 	ULONG_MAX, /* > 1 min has elapsed, give up */
94 };
95 
96 static void __ata_port_freeze(struct ata_port *ap);
97 #ifdef CONFIG_PM
98 static void ata_eh_handle_port_suspend(struct ata_port *ap);
99 static void ata_eh_handle_port_resume(struct ata_port *ap);
100 #else /* CONFIG_PM */
101 static void ata_eh_handle_port_suspend(struct ata_port *ap)
102 { }
103 
104 static void ata_eh_handle_port_resume(struct ata_port *ap)
105 { }
106 #endif /* CONFIG_PM */
107 
108 static void __ata_ehi_pushv_desc(struct ata_eh_info *ehi, const char *fmt,
109 				 va_list args)
110 {
111 	ehi->desc_len += vscnprintf(ehi->desc + ehi->desc_len,
112 				     ATA_EH_DESC_LEN - ehi->desc_len,
113 				     fmt, args);
114 }
115 
116 /**
117  *	__ata_ehi_push_desc - push error description without adding separator
118  *	@ehi: target EHI
119  *	@fmt: printf format string
120  *
121  *	Format string according to @fmt and append it to @ehi->desc.
122  *
123  *	LOCKING:
124  *	spin_lock_irqsave(host lock)
125  */
126 void __ata_ehi_push_desc(struct ata_eh_info *ehi, const char *fmt, ...)
127 {
128 	va_list args;
129 
130 	va_start(args, fmt);
131 	__ata_ehi_pushv_desc(ehi, fmt, args);
132 	va_end(args);
133 }
134 
135 /**
136  *	ata_ehi_push_desc - push error description with separator
137  *	@ehi: target EHI
138  *	@fmt: printf format string
139  *
140  *	Format string according to @fmt and append it to @ehi->desc.
141  *	If @ehi->desc is not empty, ", " is added in-between.
142  *
143  *	LOCKING:
144  *	spin_lock_irqsave(host lock)
145  */
146 void ata_ehi_push_desc(struct ata_eh_info *ehi, const char *fmt, ...)
147 {
148 	va_list args;
149 
150 	if (ehi->desc_len)
151 		__ata_ehi_push_desc(ehi, ", ");
152 
153 	va_start(args, fmt);
154 	__ata_ehi_pushv_desc(ehi, fmt, args);
155 	va_end(args);
156 }
157 
158 /**
159  *	ata_ehi_clear_desc - clean error description
160  *	@ehi: target EHI
161  *
162  *	Clear @ehi->desc.
163  *
164  *	LOCKING:
165  *	spin_lock_irqsave(host lock)
166  */
167 void ata_ehi_clear_desc(struct ata_eh_info *ehi)
168 {
169 	ehi->desc[0] = '\0';
170 	ehi->desc_len = 0;
171 }
172 
173 /**
174  *	ata_port_desc - append port description
175  *	@ap: target ATA port
176  *	@fmt: printf format string
177  *
178  *	Format string according to @fmt and append it to port
179  *	description.  If port description is not empty, " " is added
180  *	in-between.  This function is to be used while initializing
181  *	ata_host.  The description is printed on host registration.
182  *
183  *	LOCKING:
184  *	None.
185  */
186 void ata_port_desc(struct ata_port *ap, const char *fmt, ...)
187 {
188 	va_list args;
189 
190 	WARN_ON(!(ap->pflags & ATA_PFLAG_INITIALIZING));
191 
192 	if (ap->link.eh_info.desc_len)
193 		__ata_ehi_push_desc(&ap->link.eh_info, " ");
194 
195 	va_start(args, fmt);
196 	__ata_ehi_pushv_desc(&ap->link.eh_info, fmt, args);
197 	va_end(args);
198 }
199 
200 #ifdef CONFIG_PCI
201 
202 /**
203  *	ata_port_pbar_desc - append PCI BAR description
204  *	@ap: target ATA port
205  *	@bar: target PCI BAR
206  *	@offset: offset into PCI BAR
207  *	@name: name of the area
208  *
209  *	If @offset is negative, this function formats a string which
210  *	contains the name, address, size and type of the BAR and
211  *	appends it to the port description.  If @offset is zero or
212  *	positive, only name and offsetted address is appended.
213  *
214  *	LOCKING:
215  *	None.
216  */
217 void ata_port_pbar_desc(struct ata_port *ap, int bar, ssize_t offset,
218 			const char *name)
219 {
220 	struct pci_dev *pdev = to_pci_dev(ap->host->dev);
221 	char *type = "";
222 	unsigned long long start, len;
223 
224 	if (pci_resource_flags(pdev, bar) & IORESOURCE_MEM)
225 		type = "m";
226 	else if (pci_resource_flags(pdev, bar) & IORESOURCE_IO)
227 		type = "i";
228 
229 	start = (unsigned long long)pci_resource_start(pdev, bar);
230 	len = (unsigned long long)pci_resource_len(pdev, bar);
231 
232 	if (offset < 0)
233 		ata_port_desc(ap, "%s %s%llu@0x%llx", name, type, len, start);
234 	else
235 		ata_port_desc(ap, "%s 0x%llx", name,
236 				start + (unsigned long long)offset);
237 }
238 
239 #endif /* CONFIG_PCI */
240 
241 static void ata_ering_record(struct ata_ering *ering, unsigned int eflags,
242 			     unsigned int err_mask)
243 {
244 	struct ata_ering_entry *ent;
245 
246 	WARN_ON(!err_mask);
247 
248 	ering->cursor++;
249 	ering->cursor %= ATA_ERING_SIZE;
250 
251 	ent = &ering->ring[ering->cursor];
252 	ent->eflags = eflags;
253 	ent->err_mask = err_mask;
254 	ent->timestamp = get_jiffies_64();
255 }
256 
257 static struct ata_ering_entry *ata_ering_top(struct ata_ering *ering)
258 {
259 	struct ata_ering_entry *ent = &ering->ring[ering->cursor];
260 
261 	if (ent->err_mask)
262 		return ent;
263 	return NULL;
264 }
265 
266 static void ata_ering_clear(struct ata_ering *ering)
267 {
268 	memset(ering, 0, sizeof(*ering));
269 }
270 
271 static int ata_ering_map(struct ata_ering *ering,
272 			 int (*map_fn)(struct ata_ering_entry *, void *),
273 			 void *arg)
274 {
275 	int idx, rc = 0;
276 	struct ata_ering_entry *ent;
277 
278 	idx = ering->cursor;
279 	do {
280 		ent = &ering->ring[idx];
281 		if (!ent->err_mask)
282 			break;
283 		rc = map_fn(ent, arg);
284 		if (rc)
285 			break;
286 		idx = (idx - 1 + ATA_ERING_SIZE) % ATA_ERING_SIZE;
287 	} while (idx != ering->cursor);
288 
289 	return rc;
290 }
291 
292 static unsigned int ata_eh_dev_action(struct ata_device *dev)
293 {
294 	struct ata_eh_context *ehc = &dev->link->eh_context;
295 
296 	return ehc->i.action | ehc->i.dev_action[dev->devno];
297 }
298 
299 static void ata_eh_clear_action(struct ata_link *link, struct ata_device *dev,
300 				struct ata_eh_info *ehi, unsigned int action)
301 {
302 	struct ata_device *tdev;
303 
304 	if (!dev) {
305 		ehi->action &= ~action;
306 		ata_link_for_each_dev(tdev, link)
307 			ehi->dev_action[tdev->devno] &= ~action;
308 	} else {
309 		/* doesn't make sense for port-wide EH actions */
310 		WARN_ON(!(action & ATA_EH_PERDEV_MASK));
311 
312 		/* break ehi->action into ehi->dev_action */
313 		if (ehi->action & action) {
314 			ata_link_for_each_dev(tdev, link)
315 				ehi->dev_action[tdev->devno] |=
316 					ehi->action & action;
317 			ehi->action &= ~action;
318 		}
319 
320 		/* turn off the specified per-dev action */
321 		ehi->dev_action[dev->devno] &= ~action;
322 	}
323 }
324 
325 /**
326  *	ata_scsi_timed_out - SCSI layer time out callback
327  *	@cmd: timed out SCSI command
328  *
329  *	Handles SCSI layer timeout.  We race with normal completion of
330  *	the qc for @cmd.  If the qc is already gone, we lose and let
331  *	the scsi command finish (EH_HANDLED).  Otherwise, the qc has
332  *	timed out and EH should be invoked.  Prevent ata_qc_complete()
333  *	from finishing it by setting EH_SCHEDULED and return
334  *	EH_NOT_HANDLED.
335  *
336  *	TODO: kill this function once old EH is gone.
337  *
338  *	LOCKING:
339  *	Called from timer context
340  *
341  *	RETURNS:
342  *	EH_HANDLED or EH_NOT_HANDLED
343  */
344 enum scsi_eh_timer_return ata_scsi_timed_out(struct scsi_cmnd *cmd)
345 {
346 	struct Scsi_Host *host = cmd->device->host;
347 	struct ata_port *ap = ata_shost_to_port(host);
348 	unsigned long flags;
349 	struct ata_queued_cmd *qc;
350 	enum scsi_eh_timer_return ret;
351 
352 	DPRINTK("ENTER\n");
353 
354 	if (ap->ops->error_handler) {
355 		ret = EH_NOT_HANDLED;
356 		goto out;
357 	}
358 
359 	ret = EH_HANDLED;
360 	spin_lock_irqsave(ap->lock, flags);
361 	qc = ata_qc_from_tag(ap, ap->link.active_tag);
362 	if (qc) {
363 		WARN_ON(qc->scsicmd != cmd);
364 		qc->flags |= ATA_QCFLAG_EH_SCHEDULED;
365 		qc->err_mask |= AC_ERR_TIMEOUT;
366 		ret = EH_NOT_HANDLED;
367 	}
368 	spin_unlock_irqrestore(ap->lock, flags);
369 
370  out:
371 	DPRINTK("EXIT, ret=%d\n", ret);
372 	return ret;
373 }
374 
375 /**
376  *	ata_scsi_error - SCSI layer error handler callback
377  *	@host: SCSI host on which error occurred
378  *
379  *	Handles SCSI-layer-thrown error events.
380  *
381  *	LOCKING:
382  *	Inherited from SCSI layer (none, can sleep)
383  *
384  *	RETURNS:
385  *	Zero.
386  */
387 void ata_scsi_error(struct Scsi_Host *host)
388 {
389 	struct ata_port *ap = ata_shost_to_port(host);
390 	int i;
391 	unsigned long flags;
392 
393 	DPRINTK("ENTER\n");
394 
395 	/* synchronize with port task */
396 	ata_port_flush_task(ap);
397 
398 	/* synchronize with host lock and sort out timeouts */
399 
400 	/* For new EH, all qcs are finished in one of three ways -
401 	 * normal completion, error completion, and SCSI timeout.
402 	 * Both cmpletions can race against SCSI timeout.  When normal
403 	 * completion wins, the qc never reaches EH.  When error
404 	 * completion wins, the qc has ATA_QCFLAG_FAILED set.
405 	 *
406 	 * When SCSI timeout wins, things are a bit more complex.
407 	 * Normal or error completion can occur after the timeout but
408 	 * before this point.  In such cases, both types of
409 	 * completions are honored.  A scmd is determined to have
410 	 * timed out iff its associated qc is active and not failed.
411 	 */
412 	if (ap->ops->error_handler) {
413 		struct scsi_cmnd *scmd, *tmp;
414 		int nr_timedout = 0;
415 
416 		spin_lock_irqsave(ap->lock, flags);
417 
418 		list_for_each_entry_safe(scmd, tmp, &host->eh_cmd_q, eh_entry) {
419 			struct ata_queued_cmd *qc;
420 
421 			for (i = 0; i < ATA_MAX_QUEUE; i++) {
422 				qc = __ata_qc_from_tag(ap, i);
423 				if (qc->flags & ATA_QCFLAG_ACTIVE &&
424 				    qc->scsicmd == scmd)
425 					break;
426 			}
427 
428 			if (i < ATA_MAX_QUEUE) {
429 				/* the scmd has an associated qc */
430 				if (!(qc->flags & ATA_QCFLAG_FAILED)) {
431 					/* which hasn't failed yet, timeout */
432 					qc->err_mask |= AC_ERR_TIMEOUT;
433 					qc->flags |= ATA_QCFLAG_FAILED;
434 					nr_timedout++;
435 				}
436 			} else {
437 				/* Normal completion occurred after
438 				 * SCSI timeout but before this point.
439 				 * Successfully complete it.
440 				 */
441 				scmd->retries = scmd->allowed;
442 				scsi_eh_finish_cmd(scmd, &ap->eh_done_q);
443 			}
444 		}
445 
446 		/* If we have timed out qcs.  They belong to EH from
447 		 * this point but the state of the controller is
448 		 * unknown.  Freeze the port to make sure the IRQ
449 		 * handler doesn't diddle with those qcs.  This must
450 		 * be done atomically w.r.t. setting QCFLAG_FAILED.
451 		 */
452 		if (nr_timedout)
453 			__ata_port_freeze(ap);
454 
455 		spin_unlock_irqrestore(ap->lock, flags);
456 
457 		/* initialize eh_tries */
458 		ap->eh_tries = ATA_EH_MAX_TRIES;
459 	} else
460 		spin_unlock_wait(ap->lock);
461 
462  repeat:
463 	/* invoke error handler */
464 	if (ap->ops->error_handler) {
465 		struct ata_link *link;
466 
467 		/* kill fast drain timer */
468 		del_timer_sync(&ap->fastdrain_timer);
469 
470 		/* process port resume request */
471 		ata_eh_handle_port_resume(ap);
472 
473 		/* fetch & clear EH info */
474 		spin_lock_irqsave(ap->lock, flags);
475 
476 		__ata_port_for_each_link(link, ap) {
477 			struct ata_eh_context *ehc = &link->eh_context;
478 			struct ata_device *dev;
479 
480 			memset(&link->eh_context, 0, sizeof(link->eh_context));
481 			link->eh_context.i = link->eh_info;
482 			memset(&link->eh_info, 0, sizeof(link->eh_info));
483 
484 			ata_link_for_each_dev(dev, link) {
485 				int devno = dev->devno;
486 
487 				ehc->saved_xfer_mode[devno] = dev->xfer_mode;
488 				if (ata_ncq_enabled(dev))
489 					ehc->saved_ncq_enabled |= 1 << devno;
490 			}
491 
492 			/* set last reset timestamp to some time in the past */
493 			ehc->last_reset = jiffies - 60 * HZ;
494 		}
495 
496 		ap->pflags |= ATA_PFLAG_EH_IN_PROGRESS;
497 		ap->pflags &= ~ATA_PFLAG_EH_PENDING;
498 		ap->excl_link = NULL;	/* don't maintain exclusion over EH */
499 
500 		spin_unlock_irqrestore(ap->lock, flags);
501 
502 		/* invoke EH, skip if unloading or suspended */
503 		if (!(ap->pflags & (ATA_PFLAG_UNLOADING | ATA_PFLAG_SUSPENDED)))
504 			ap->ops->error_handler(ap);
505 		else
506 			ata_eh_finish(ap);
507 
508 		/* process port suspend request */
509 		ata_eh_handle_port_suspend(ap);
510 
511 		/* Exception might have happend after ->error_handler
512 		 * recovered the port but before this point.  Repeat
513 		 * EH in such case.
514 		 */
515 		spin_lock_irqsave(ap->lock, flags);
516 
517 		if (ap->pflags & ATA_PFLAG_EH_PENDING) {
518 			if (--ap->eh_tries) {
519 				spin_unlock_irqrestore(ap->lock, flags);
520 				goto repeat;
521 			}
522 			ata_port_printk(ap, KERN_ERR, "EH pending after %d "
523 					"tries, giving up\n", ATA_EH_MAX_TRIES);
524 			ap->pflags &= ~ATA_PFLAG_EH_PENDING;
525 		}
526 
527 		/* this run is complete, make sure EH info is clear */
528 		__ata_port_for_each_link(link, ap)
529 			memset(&link->eh_info, 0, sizeof(link->eh_info));
530 
531 		/* Clear host_eh_scheduled while holding ap->lock such
532 		 * that if exception occurs after this point but
533 		 * before EH completion, SCSI midlayer will
534 		 * re-initiate EH.
535 		 */
536 		host->host_eh_scheduled = 0;
537 
538 		spin_unlock_irqrestore(ap->lock, flags);
539 	} else {
540 		WARN_ON(ata_qc_from_tag(ap, ap->link.active_tag) == NULL);
541 		ap->ops->eng_timeout(ap);
542 	}
543 
544 	/* finish or retry handled scmd's and clean up */
545 	WARN_ON(host->host_failed || !list_empty(&host->eh_cmd_q));
546 
547 	scsi_eh_flush_done_q(&ap->eh_done_q);
548 
549 	/* clean up */
550 	spin_lock_irqsave(ap->lock, flags);
551 
552 	if (ap->pflags & ATA_PFLAG_LOADING)
553 		ap->pflags &= ~ATA_PFLAG_LOADING;
554 	else if (ap->pflags & ATA_PFLAG_SCSI_HOTPLUG)
555 		queue_delayed_work(ata_aux_wq, &ap->hotplug_task, 0);
556 
557 	if (ap->pflags & ATA_PFLAG_RECOVERED)
558 		ata_port_printk(ap, KERN_INFO, "EH complete\n");
559 
560 	ap->pflags &= ~(ATA_PFLAG_SCSI_HOTPLUG | ATA_PFLAG_RECOVERED);
561 
562 	/* tell wait_eh that we're done */
563 	ap->pflags &= ~ATA_PFLAG_EH_IN_PROGRESS;
564 	wake_up_all(&ap->eh_wait_q);
565 
566 	spin_unlock_irqrestore(ap->lock, flags);
567 
568 	DPRINTK("EXIT\n");
569 }
570 
571 /**
572  *	ata_port_wait_eh - Wait for the currently pending EH to complete
573  *	@ap: Port to wait EH for
574  *
575  *	Wait until the currently pending EH is complete.
576  *
577  *	LOCKING:
578  *	Kernel thread context (may sleep).
579  */
580 void ata_port_wait_eh(struct ata_port *ap)
581 {
582 	unsigned long flags;
583 	DEFINE_WAIT(wait);
584 
585  retry:
586 	spin_lock_irqsave(ap->lock, flags);
587 
588 	while (ap->pflags & (ATA_PFLAG_EH_PENDING | ATA_PFLAG_EH_IN_PROGRESS)) {
589 		prepare_to_wait(&ap->eh_wait_q, &wait, TASK_UNINTERRUPTIBLE);
590 		spin_unlock_irqrestore(ap->lock, flags);
591 		schedule();
592 		spin_lock_irqsave(ap->lock, flags);
593 	}
594 	finish_wait(&ap->eh_wait_q, &wait);
595 
596 	spin_unlock_irqrestore(ap->lock, flags);
597 
598 	/* make sure SCSI EH is complete */
599 	if (scsi_host_in_recovery(ap->scsi_host)) {
600 		msleep(10);
601 		goto retry;
602 	}
603 }
604 
605 static int ata_eh_nr_in_flight(struct ata_port *ap)
606 {
607 	unsigned int tag;
608 	int nr = 0;
609 
610 	/* count only non-internal commands */
611 	for (tag = 0; tag < ATA_MAX_QUEUE - 1; tag++)
612 		if (ata_qc_from_tag(ap, tag))
613 			nr++;
614 
615 	return nr;
616 }
617 
618 void ata_eh_fastdrain_timerfn(unsigned long arg)
619 {
620 	struct ata_port *ap = (void *)arg;
621 	unsigned long flags;
622 	int cnt;
623 
624 	spin_lock_irqsave(ap->lock, flags);
625 
626 	cnt = ata_eh_nr_in_flight(ap);
627 
628 	/* are we done? */
629 	if (!cnt)
630 		goto out_unlock;
631 
632 	if (cnt == ap->fastdrain_cnt) {
633 		unsigned int tag;
634 
635 		/* No progress during the last interval, tag all
636 		 * in-flight qcs as timed out and freeze the port.
637 		 */
638 		for (tag = 0; tag < ATA_MAX_QUEUE - 1; tag++) {
639 			struct ata_queued_cmd *qc = ata_qc_from_tag(ap, tag);
640 			if (qc)
641 				qc->err_mask |= AC_ERR_TIMEOUT;
642 		}
643 
644 		ata_port_freeze(ap);
645 	} else {
646 		/* some qcs have finished, give it another chance */
647 		ap->fastdrain_cnt = cnt;
648 		ap->fastdrain_timer.expires =
649 			ata_deadline(jiffies, ATA_EH_FASTDRAIN_INTERVAL);
650 		add_timer(&ap->fastdrain_timer);
651 	}
652 
653  out_unlock:
654 	spin_unlock_irqrestore(ap->lock, flags);
655 }
656 
657 /**
658  *	ata_eh_set_pending - set ATA_PFLAG_EH_PENDING and activate fast drain
659  *	@ap: target ATA port
660  *	@fastdrain: activate fast drain
661  *
662  *	Set ATA_PFLAG_EH_PENDING and activate fast drain if @fastdrain
663  *	is non-zero and EH wasn't pending before.  Fast drain ensures
664  *	that EH kicks in in timely manner.
665  *
666  *	LOCKING:
667  *	spin_lock_irqsave(host lock)
668  */
669 static void ata_eh_set_pending(struct ata_port *ap, int fastdrain)
670 {
671 	int cnt;
672 
673 	/* already scheduled? */
674 	if (ap->pflags & ATA_PFLAG_EH_PENDING)
675 		return;
676 
677 	ap->pflags |= ATA_PFLAG_EH_PENDING;
678 
679 	if (!fastdrain)
680 		return;
681 
682 	/* do we have in-flight qcs? */
683 	cnt = ata_eh_nr_in_flight(ap);
684 	if (!cnt)
685 		return;
686 
687 	/* activate fast drain */
688 	ap->fastdrain_cnt = cnt;
689 	ap->fastdrain_timer.expires =
690 		ata_deadline(jiffies, ATA_EH_FASTDRAIN_INTERVAL);
691 	add_timer(&ap->fastdrain_timer);
692 }
693 
694 /**
695  *	ata_qc_schedule_eh - schedule qc for error handling
696  *	@qc: command to schedule error handling for
697  *
698  *	Schedule error handling for @qc.  EH will kick in as soon as
699  *	other commands are drained.
700  *
701  *	LOCKING:
702  *	spin_lock_irqsave(host lock)
703  */
704 void ata_qc_schedule_eh(struct ata_queued_cmd *qc)
705 {
706 	struct ata_port *ap = qc->ap;
707 
708 	WARN_ON(!ap->ops->error_handler);
709 
710 	qc->flags |= ATA_QCFLAG_FAILED;
711 	ata_eh_set_pending(ap, 1);
712 
713 	/* The following will fail if timeout has already expired.
714 	 * ata_scsi_error() takes care of such scmds on EH entry.
715 	 * Note that ATA_QCFLAG_FAILED is unconditionally set after
716 	 * this function completes.
717 	 */
718 	scsi_req_abort_cmd(qc->scsicmd);
719 }
720 
721 /**
722  *	ata_port_schedule_eh - schedule error handling without a qc
723  *	@ap: ATA port to schedule EH for
724  *
725  *	Schedule error handling for @ap.  EH will kick in as soon as
726  *	all commands are drained.
727  *
728  *	LOCKING:
729  *	spin_lock_irqsave(host lock)
730  */
731 void ata_port_schedule_eh(struct ata_port *ap)
732 {
733 	WARN_ON(!ap->ops->error_handler);
734 
735 	if (ap->pflags & ATA_PFLAG_INITIALIZING)
736 		return;
737 
738 	ata_eh_set_pending(ap, 1);
739 	scsi_schedule_eh(ap->scsi_host);
740 
741 	DPRINTK("port EH scheduled\n");
742 }
743 
744 static int ata_do_link_abort(struct ata_port *ap, struct ata_link *link)
745 {
746 	int tag, nr_aborted = 0;
747 
748 	WARN_ON(!ap->ops->error_handler);
749 
750 	/* we're gonna abort all commands, no need for fast drain */
751 	ata_eh_set_pending(ap, 0);
752 
753 	for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
754 		struct ata_queued_cmd *qc = ata_qc_from_tag(ap, tag);
755 
756 		if (qc && (!link || qc->dev->link == link)) {
757 			qc->flags |= ATA_QCFLAG_FAILED;
758 			ata_qc_complete(qc);
759 			nr_aborted++;
760 		}
761 	}
762 
763 	if (!nr_aborted)
764 		ata_port_schedule_eh(ap);
765 
766 	return nr_aborted;
767 }
768 
769 /**
770  *	ata_link_abort - abort all qc's on the link
771  *	@link: ATA link to abort qc's for
772  *
773  *	Abort all active qc's active on @link and schedule EH.
774  *
775  *	LOCKING:
776  *	spin_lock_irqsave(host lock)
777  *
778  *	RETURNS:
779  *	Number of aborted qc's.
780  */
781 int ata_link_abort(struct ata_link *link)
782 {
783 	return ata_do_link_abort(link->ap, link);
784 }
785 
786 /**
787  *	ata_port_abort - abort all qc's on the port
788  *	@ap: ATA port to abort qc's for
789  *
790  *	Abort all active qc's of @ap and schedule EH.
791  *
792  *	LOCKING:
793  *	spin_lock_irqsave(host_set lock)
794  *
795  *	RETURNS:
796  *	Number of aborted qc's.
797  */
798 int ata_port_abort(struct ata_port *ap)
799 {
800 	return ata_do_link_abort(ap, NULL);
801 }
802 
803 /**
804  *	__ata_port_freeze - freeze port
805  *	@ap: ATA port to freeze
806  *
807  *	This function is called when HSM violation or some other
808  *	condition disrupts normal operation of the port.  Frozen port
809  *	is not allowed to perform any operation until the port is
810  *	thawed, which usually follows a successful reset.
811  *
812  *	ap->ops->freeze() callback can be used for freezing the port
813  *	hardware-wise (e.g. mask interrupt and stop DMA engine).  If a
814  *	port cannot be frozen hardware-wise, the interrupt handler
815  *	must ack and clear interrupts unconditionally while the port
816  *	is frozen.
817  *
818  *	LOCKING:
819  *	spin_lock_irqsave(host lock)
820  */
821 static void __ata_port_freeze(struct ata_port *ap)
822 {
823 	WARN_ON(!ap->ops->error_handler);
824 
825 	if (ap->ops->freeze)
826 		ap->ops->freeze(ap);
827 
828 	ap->pflags |= ATA_PFLAG_FROZEN;
829 
830 	DPRINTK("ata%u port frozen\n", ap->print_id);
831 }
832 
833 /**
834  *	ata_port_freeze - abort & freeze port
835  *	@ap: ATA port to freeze
836  *
837  *	Abort and freeze @ap.
838  *
839  *	LOCKING:
840  *	spin_lock_irqsave(host lock)
841  *
842  *	RETURNS:
843  *	Number of aborted commands.
844  */
845 int ata_port_freeze(struct ata_port *ap)
846 {
847 	int nr_aborted;
848 
849 	WARN_ON(!ap->ops->error_handler);
850 
851 	nr_aborted = ata_port_abort(ap);
852 	__ata_port_freeze(ap);
853 
854 	return nr_aborted;
855 }
856 
857 /**
858  *	sata_async_notification - SATA async notification handler
859  *	@ap: ATA port where async notification is received
860  *
861  *	Handler to be called when async notification via SDB FIS is
862  *	received.  This function schedules EH if necessary.
863  *
864  *	LOCKING:
865  *	spin_lock_irqsave(host lock)
866  *
867  *	RETURNS:
868  *	1 if EH is scheduled, 0 otherwise.
869  */
870 int sata_async_notification(struct ata_port *ap)
871 {
872 	u32 sntf;
873 	int rc;
874 
875 	if (!(ap->flags & ATA_FLAG_AN))
876 		return 0;
877 
878 	rc = sata_scr_read(&ap->link, SCR_NOTIFICATION, &sntf);
879 	if (rc == 0)
880 		sata_scr_write(&ap->link, SCR_NOTIFICATION, sntf);
881 
882 	if (!sata_pmp_attached(ap) || rc) {
883 		/* PMP is not attached or SNTF is not available */
884 		if (!sata_pmp_attached(ap)) {
885 			/* PMP is not attached.  Check whether ATAPI
886 			 * AN is configured.  If so, notify media
887 			 * change.
888 			 */
889 			struct ata_device *dev = ap->link.device;
890 
891 			if ((dev->class == ATA_DEV_ATAPI) &&
892 			    (dev->flags & ATA_DFLAG_AN))
893 				ata_scsi_media_change_notify(dev);
894 			return 0;
895 		} else {
896 			/* PMP is attached but SNTF is not available.
897 			 * ATAPI async media change notification is
898 			 * not used.  The PMP must be reporting PHY
899 			 * status change, schedule EH.
900 			 */
901 			ata_port_schedule_eh(ap);
902 			return 1;
903 		}
904 	} else {
905 		/* PMP is attached and SNTF is available */
906 		struct ata_link *link;
907 
908 		/* check and notify ATAPI AN */
909 		ata_port_for_each_link(link, ap) {
910 			if (!(sntf & (1 << link->pmp)))
911 				continue;
912 
913 			if ((link->device->class == ATA_DEV_ATAPI) &&
914 			    (link->device->flags & ATA_DFLAG_AN))
915 				ata_scsi_media_change_notify(link->device);
916 		}
917 
918 		/* If PMP is reporting that PHY status of some
919 		 * downstream ports has changed, schedule EH.
920 		 */
921 		if (sntf & (1 << SATA_PMP_CTRL_PORT)) {
922 			ata_port_schedule_eh(ap);
923 			return 1;
924 		}
925 
926 		return 0;
927 	}
928 }
929 
930 /**
931  *	ata_eh_freeze_port - EH helper to freeze port
932  *	@ap: ATA port to freeze
933  *
934  *	Freeze @ap.
935  *
936  *	LOCKING:
937  *	None.
938  */
939 void ata_eh_freeze_port(struct ata_port *ap)
940 {
941 	unsigned long flags;
942 
943 	if (!ap->ops->error_handler)
944 		return;
945 
946 	spin_lock_irqsave(ap->lock, flags);
947 	__ata_port_freeze(ap);
948 	spin_unlock_irqrestore(ap->lock, flags);
949 }
950 
951 /**
952  *	ata_port_thaw_port - EH helper to thaw port
953  *	@ap: ATA port to thaw
954  *
955  *	Thaw frozen port @ap.
956  *
957  *	LOCKING:
958  *	None.
959  */
960 void ata_eh_thaw_port(struct ata_port *ap)
961 {
962 	unsigned long flags;
963 
964 	if (!ap->ops->error_handler)
965 		return;
966 
967 	spin_lock_irqsave(ap->lock, flags);
968 
969 	ap->pflags &= ~ATA_PFLAG_FROZEN;
970 
971 	if (ap->ops->thaw)
972 		ap->ops->thaw(ap);
973 
974 	spin_unlock_irqrestore(ap->lock, flags);
975 
976 	DPRINTK("ata%u port thawed\n", ap->print_id);
977 }
978 
979 static void ata_eh_scsidone(struct scsi_cmnd *scmd)
980 {
981 	/* nada */
982 }
983 
984 static void __ata_eh_qc_complete(struct ata_queued_cmd *qc)
985 {
986 	struct ata_port *ap = qc->ap;
987 	struct scsi_cmnd *scmd = qc->scsicmd;
988 	unsigned long flags;
989 
990 	spin_lock_irqsave(ap->lock, flags);
991 	qc->scsidone = ata_eh_scsidone;
992 	__ata_qc_complete(qc);
993 	WARN_ON(ata_tag_valid(qc->tag));
994 	spin_unlock_irqrestore(ap->lock, flags);
995 
996 	scsi_eh_finish_cmd(scmd, &ap->eh_done_q);
997 }
998 
999 /**
1000  *	ata_eh_qc_complete - Complete an active ATA command from EH
1001  *	@qc: Command to complete
1002  *
1003  *	Indicate to the mid and upper layers that an ATA command has
1004  *	completed.  To be used from EH.
1005  */
1006 void ata_eh_qc_complete(struct ata_queued_cmd *qc)
1007 {
1008 	struct scsi_cmnd *scmd = qc->scsicmd;
1009 	scmd->retries = scmd->allowed;
1010 	__ata_eh_qc_complete(qc);
1011 }
1012 
1013 /**
1014  *	ata_eh_qc_retry - Tell midlayer to retry an ATA command after EH
1015  *	@qc: Command to retry
1016  *
1017  *	Indicate to the mid and upper layers that an ATA command
1018  *	should be retried.  To be used from EH.
1019  *
1020  *	SCSI midlayer limits the number of retries to scmd->allowed.
1021  *	scmd->retries is decremented for commands which get retried
1022  *	due to unrelated failures (qc->err_mask is zero).
1023  */
1024 void ata_eh_qc_retry(struct ata_queued_cmd *qc)
1025 {
1026 	struct scsi_cmnd *scmd = qc->scsicmd;
1027 	if (!qc->err_mask && scmd->retries)
1028 		scmd->retries--;
1029 	__ata_eh_qc_complete(qc);
1030 }
1031 
1032 /**
1033  *	ata_eh_detach_dev - detach ATA device
1034  *	@dev: ATA device to detach
1035  *
1036  *	Detach @dev.
1037  *
1038  *	LOCKING:
1039  *	None.
1040  */
1041 void ata_eh_detach_dev(struct ata_device *dev)
1042 {
1043 	struct ata_link *link = dev->link;
1044 	struct ata_port *ap = link->ap;
1045 	unsigned long flags;
1046 
1047 	ata_dev_disable(dev);
1048 
1049 	spin_lock_irqsave(ap->lock, flags);
1050 
1051 	dev->flags &= ~ATA_DFLAG_DETACH;
1052 
1053 	if (ata_scsi_offline_dev(dev)) {
1054 		dev->flags |= ATA_DFLAG_DETACHED;
1055 		ap->pflags |= ATA_PFLAG_SCSI_HOTPLUG;
1056 	}
1057 
1058 	/* clear per-dev EH actions */
1059 	ata_eh_clear_action(link, dev, &link->eh_info, ATA_EH_PERDEV_MASK);
1060 	ata_eh_clear_action(link, dev, &link->eh_context.i, ATA_EH_PERDEV_MASK);
1061 
1062 	spin_unlock_irqrestore(ap->lock, flags);
1063 }
1064 
1065 /**
1066  *	ata_eh_about_to_do - about to perform eh_action
1067  *	@link: target ATA link
1068  *	@dev: target ATA dev for per-dev action (can be NULL)
1069  *	@action: action about to be performed
1070  *
1071  *	Called just before performing EH actions to clear related bits
1072  *	in @link->eh_info such that eh actions are not unnecessarily
1073  *	repeated.
1074  *
1075  *	LOCKING:
1076  *	None.
1077  */
1078 void ata_eh_about_to_do(struct ata_link *link, struct ata_device *dev,
1079 			unsigned int action)
1080 {
1081 	struct ata_port *ap = link->ap;
1082 	struct ata_eh_info *ehi = &link->eh_info;
1083 	struct ata_eh_context *ehc = &link->eh_context;
1084 	unsigned long flags;
1085 
1086 	spin_lock_irqsave(ap->lock, flags);
1087 
1088 	ata_eh_clear_action(link, dev, ehi, action);
1089 
1090 	if (!(ehc->i.flags & ATA_EHI_QUIET))
1091 		ap->pflags |= ATA_PFLAG_RECOVERED;
1092 
1093 	spin_unlock_irqrestore(ap->lock, flags);
1094 }
1095 
1096 /**
1097  *	ata_eh_done - EH action complete
1098 *	@ap: target ATA port
1099  *	@dev: target ATA dev for per-dev action (can be NULL)
1100  *	@action: action just completed
1101  *
1102  *	Called right after performing EH actions to clear related bits
1103  *	in @link->eh_context.
1104  *
1105  *	LOCKING:
1106  *	None.
1107  */
1108 void ata_eh_done(struct ata_link *link, struct ata_device *dev,
1109 		 unsigned int action)
1110 {
1111 	struct ata_eh_context *ehc = &link->eh_context;
1112 
1113 	ata_eh_clear_action(link, dev, &ehc->i, action);
1114 }
1115 
1116 /**
1117  *	ata_err_string - convert err_mask to descriptive string
1118  *	@err_mask: error mask to convert to string
1119  *
1120  *	Convert @err_mask to descriptive string.  Errors are
1121  *	prioritized according to severity and only the most severe
1122  *	error is reported.
1123  *
1124  *	LOCKING:
1125  *	None.
1126  *
1127  *	RETURNS:
1128  *	Descriptive string for @err_mask
1129  */
1130 static const char *ata_err_string(unsigned int err_mask)
1131 {
1132 	if (err_mask & AC_ERR_HOST_BUS)
1133 		return "host bus error";
1134 	if (err_mask & AC_ERR_ATA_BUS)
1135 		return "ATA bus error";
1136 	if (err_mask & AC_ERR_TIMEOUT)
1137 		return "timeout";
1138 	if (err_mask & AC_ERR_HSM)
1139 		return "HSM violation";
1140 	if (err_mask & AC_ERR_SYSTEM)
1141 		return "internal error";
1142 	if (err_mask & AC_ERR_MEDIA)
1143 		return "media error";
1144 	if (err_mask & AC_ERR_INVALID)
1145 		return "invalid argument";
1146 	if (err_mask & AC_ERR_DEV)
1147 		return "device error";
1148 	return "unknown error";
1149 }
1150 
1151 /**
1152  *	ata_read_log_page - read a specific log page
1153  *	@dev: target device
1154  *	@page: page to read
1155  *	@buf: buffer to store read page
1156  *	@sectors: number of sectors to read
1157  *
1158  *	Read log page using READ_LOG_EXT command.
1159  *
1160  *	LOCKING:
1161  *	Kernel thread context (may sleep).
1162  *
1163  *	RETURNS:
1164  *	0 on success, AC_ERR_* mask otherwise.
1165  */
1166 static unsigned int ata_read_log_page(struct ata_device *dev,
1167 				      u8 page, void *buf, unsigned int sectors)
1168 {
1169 	struct ata_taskfile tf;
1170 	unsigned int err_mask;
1171 
1172 	DPRINTK("read log page - page %d\n", page);
1173 
1174 	ata_tf_init(dev, &tf);
1175 	tf.command = ATA_CMD_READ_LOG_EXT;
1176 	tf.lbal = page;
1177 	tf.nsect = sectors;
1178 	tf.hob_nsect = sectors >> 8;
1179 	tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_LBA48 | ATA_TFLAG_DEVICE;
1180 	tf.protocol = ATA_PROT_PIO;
1181 
1182 	err_mask = ata_exec_internal(dev, &tf, NULL, DMA_FROM_DEVICE,
1183 				     buf, sectors * ATA_SECT_SIZE, 0);
1184 
1185 	DPRINTK("EXIT, err_mask=%x\n", err_mask);
1186 	return err_mask;
1187 }
1188 
1189 /**
1190  *	ata_eh_read_log_10h - Read log page 10h for NCQ error details
1191  *	@dev: Device to read log page 10h from
1192  *	@tag: Resulting tag of the failed command
1193  *	@tf: Resulting taskfile registers of the failed command
1194  *
1195  *	Read log page 10h to obtain NCQ error details and clear error
1196  *	condition.
1197  *
1198  *	LOCKING:
1199  *	Kernel thread context (may sleep).
1200  *
1201  *	RETURNS:
1202  *	0 on success, -errno otherwise.
1203  */
1204 static int ata_eh_read_log_10h(struct ata_device *dev,
1205 			       int *tag, struct ata_taskfile *tf)
1206 {
1207 	u8 *buf = dev->link->ap->sector_buf;
1208 	unsigned int err_mask;
1209 	u8 csum;
1210 	int i;
1211 
1212 	err_mask = ata_read_log_page(dev, ATA_LOG_SATA_NCQ, buf, 1);
1213 	if (err_mask)
1214 		return -EIO;
1215 
1216 	csum = 0;
1217 	for (i = 0; i < ATA_SECT_SIZE; i++)
1218 		csum += buf[i];
1219 	if (csum)
1220 		ata_dev_printk(dev, KERN_WARNING,
1221 			       "invalid checksum 0x%x on log page 10h\n", csum);
1222 
1223 	if (buf[0] & 0x80)
1224 		return -ENOENT;
1225 
1226 	*tag = buf[0] & 0x1f;
1227 
1228 	tf->command = buf[2];
1229 	tf->feature = buf[3];
1230 	tf->lbal = buf[4];
1231 	tf->lbam = buf[5];
1232 	tf->lbah = buf[6];
1233 	tf->device = buf[7];
1234 	tf->hob_lbal = buf[8];
1235 	tf->hob_lbam = buf[9];
1236 	tf->hob_lbah = buf[10];
1237 	tf->nsect = buf[12];
1238 	tf->hob_nsect = buf[13];
1239 
1240 	return 0;
1241 }
1242 
1243 /**
1244  *	atapi_eh_request_sense - perform ATAPI REQUEST_SENSE
1245  *	@dev: device to perform REQUEST_SENSE to
1246  *	@sense_buf: result sense data buffer (SCSI_SENSE_BUFFERSIZE bytes long)
1247  *
1248  *	Perform ATAPI REQUEST_SENSE after the device reported CHECK
1249  *	SENSE.  This function is EH helper.
1250  *
1251  *	LOCKING:
1252  *	Kernel thread context (may sleep).
1253  *
1254  *	RETURNS:
1255  *	0 on success, AC_ERR_* mask on failure
1256  */
1257 static unsigned int atapi_eh_request_sense(struct ata_queued_cmd *qc)
1258 {
1259 	struct ata_device *dev = qc->dev;
1260 	unsigned char *sense_buf = qc->scsicmd->sense_buffer;
1261 	struct ata_port *ap = dev->link->ap;
1262 	struct ata_taskfile tf;
1263 	u8 cdb[ATAPI_CDB_LEN];
1264 
1265 	DPRINTK("ATAPI request sense\n");
1266 
1267 	/* FIXME: is this needed? */
1268 	memset(sense_buf, 0, SCSI_SENSE_BUFFERSIZE);
1269 
1270 	/* initialize sense_buf with the error register,
1271 	 * for the case where they are -not- overwritten
1272 	 */
1273 	sense_buf[0] = 0x70;
1274 	sense_buf[2] = qc->result_tf.feature >> 4;
1275 
1276 	/* some devices time out if garbage left in tf */
1277 	ata_tf_init(dev, &tf);
1278 
1279 	memset(cdb, 0, ATAPI_CDB_LEN);
1280 	cdb[0] = REQUEST_SENSE;
1281 	cdb[4] = SCSI_SENSE_BUFFERSIZE;
1282 
1283 	tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
1284 	tf.command = ATA_CMD_PACKET;
1285 
1286 	/* is it pointless to prefer PIO for "safety reasons"? */
1287 	if (ap->flags & ATA_FLAG_PIO_DMA) {
1288 		tf.protocol = ATAPI_PROT_DMA;
1289 		tf.feature |= ATAPI_PKT_DMA;
1290 	} else {
1291 		tf.protocol = ATAPI_PROT_PIO;
1292 		tf.lbam = SCSI_SENSE_BUFFERSIZE;
1293 		tf.lbah = 0;
1294 	}
1295 
1296 	return ata_exec_internal(dev, &tf, cdb, DMA_FROM_DEVICE,
1297 				 sense_buf, SCSI_SENSE_BUFFERSIZE, 0);
1298 }
1299 
1300 /**
1301  *	ata_eh_analyze_serror - analyze SError for a failed port
1302  *	@link: ATA link to analyze SError for
1303  *
1304  *	Analyze SError if available and further determine cause of
1305  *	failure.
1306  *
1307  *	LOCKING:
1308  *	None.
1309  */
1310 static void ata_eh_analyze_serror(struct ata_link *link)
1311 {
1312 	struct ata_eh_context *ehc = &link->eh_context;
1313 	u32 serror = ehc->i.serror;
1314 	unsigned int err_mask = 0, action = 0;
1315 	u32 hotplug_mask;
1316 
1317 	if (serror & (SERR_PERSISTENT | SERR_DATA)) {
1318 		err_mask |= AC_ERR_ATA_BUS;
1319 		action |= ATA_EH_RESET;
1320 	}
1321 	if (serror & SERR_PROTOCOL) {
1322 		err_mask |= AC_ERR_HSM;
1323 		action |= ATA_EH_RESET;
1324 	}
1325 	if (serror & SERR_INTERNAL) {
1326 		err_mask |= AC_ERR_SYSTEM;
1327 		action |= ATA_EH_RESET;
1328 	}
1329 
1330 	/* Determine whether a hotplug event has occurred.  Both
1331 	 * SError.N/X are considered hotplug events for enabled or
1332 	 * host links.  For disabled PMP links, only N bit is
1333 	 * considered as X bit is left at 1 for link plugging.
1334 	 */
1335 	hotplug_mask = 0;
1336 
1337 	if (!(link->flags & ATA_LFLAG_DISABLED) || ata_is_host_link(link))
1338 		hotplug_mask = SERR_PHYRDY_CHG | SERR_DEV_XCHG;
1339 	else
1340 		hotplug_mask = SERR_PHYRDY_CHG;
1341 
1342 	if (serror & hotplug_mask)
1343 		ata_ehi_hotplugged(&ehc->i);
1344 
1345 	ehc->i.err_mask |= err_mask;
1346 	ehc->i.action |= action;
1347 }
1348 
1349 /**
1350  *	ata_eh_analyze_ncq_error - analyze NCQ error
1351  *	@link: ATA link to analyze NCQ error for
1352  *
1353  *	Read log page 10h, determine the offending qc and acquire
1354  *	error status TF.  For NCQ device errors, all LLDDs have to do
1355  *	is setting AC_ERR_DEV in ehi->err_mask.  This function takes
1356  *	care of the rest.
1357  *
1358  *	LOCKING:
1359  *	Kernel thread context (may sleep).
1360  */
1361 void ata_eh_analyze_ncq_error(struct ata_link *link)
1362 {
1363 	struct ata_port *ap = link->ap;
1364 	struct ata_eh_context *ehc = &link->eh_context;
1365 	struct ata_device *dev = link->device;
1366 	struct ata_queued_cmd *qc;
1367 	struct ata_taskfile tf;
1368 	int tag, rc;
1369 
1370 	/* if frozen, we can't do much */
1371 	if (ap->pflags & ATA_PFLAG_FROZEN)
1372 		return;
1373 
1374 	/* is it NCQ device error? */
1375 	if (!link->sactive || !(ehc->i.err_mask & AC_ERR_DEV))
1376 		return;
1377 
1378 	/* has LLDD analyzed already? */
1379 	for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
1380 		qc = __ata_qc_from_tag(ap, tag);
1381 
1382 		if (!(qc->flags & ATA_QCFLAG_FAILED))
1383 			continue;
1384 
1385 		if (qc->err_mask)
1386 			return;
1387 	}
1388 
1389 	/* okay, this error is ours */
1390 	rc = ata_eh_read_log_10h(dev, &tag, &tf);
1391 	if (rc) {
1392 		ata_link_printk(link, KERN_ERR, "failed to read log page 10h "
1393 				"(errno=%d)\n", rc);
1394 		return;
1395 	}
1396 
1397 	if (!(link->sactive & (1 << tag))) {
1398 		ata_link_printk(link, KERN_ERR, "log page 10h reported "
1399 				"inactive tag %d\n", tag);
1400 		return;
1401 	}
1402 
1403 	/* we've got the perpetrator, condemn it */
1404 	qc = __ata_qc_from_tag(ap, tag);
1405 	memcpy(&qc->result_tf, &tf, sizeof(tf));
1406 	qc->result_tf.flags = ATA_TFLAG_ISADDR | ATA_TFLAG_LBA | ATA_TFLAG_LBA48;
1407 	qc->err_mask |= AC_ERR_DEV | AC_ERR_NCQ;
1408 	ehc->i.err_mask &= ~AC_ERR_DEV;
1409 }
1410 
1411 /**
1412  *	ata_eh_analyze_tf - analyze taskfile of a failed qc
1413  *	@qc: qc to analyze
1414  *	@tf: Taskfile registers to analyze
1415  *
1416  *	Analyze taskfile of @qc and further determine cause of
1417  *	failure.  This function also requests ATAPI sense data if
1418  *	avaliable.
1419  *
1420  *	LOCKING:
1421  *	Kernel thread context (may sleep).
1422  *
1423  *	RETURNS:
1424  *	Determined recovery action
1425  */
1426 static unsigned int ata_eh_analyze_tf(struct ata_queued_cmd *qc,
1427 				      const struct ata_taskfile *tf)
1428 {
1429 	unsigned int tmp, action = 0;
1430 	u8 stat = tf->command, err = tf->feature;
1431 
1432 	if ((stat & (ATA_BUSY | ATA_DRQ | ATA_DRDY)) != ATA_DRDY) {
1433 		qc->err_mask |= AC_ERR_HSM;
1434 		return ATA_EH_RESET;
1435 	}
1436 
1437 	if (stat & (ATA_ERR | ATA_DF))
1438 		qc->err_mask |= AC_ERR_DEV;
1439 	else
1440 		return 0;
1441 
1442 	switch (qc->dev->class) {
1443 	case ATA_DEV_ATA:
1444 		if (err & ATA_ICRC)
1445 			qc->err_mask |= AC_ERR_ATA_BUS;
1446 		if (err & ATA_UNC)
1447 			qc->err_mask |= AC_ERR_MEDIA;
1448 		if (err & ATA_IDNF)
1449 			qc->err_mask |= AC_ERR_INVALID;
1450 		break;
1451 
1452 	case ATA_DEV_ATAPI:
1453 		if (!(qc->ap->pflags & ATA_PFLAG_FROZEN)) {
1454 			tmp = atapi_eh_request_sense(qc);
1455 			if (!tmp) {
1456 				/* ATA_QCFLAG_SENSE_VALID is used to
1457 				 * tell atapi_qc_complete() that sense
1458 				 * data is already valid.
1459 				 *
1460 				 * TODO: interpret sense data and set
1461 				 * appropriate err_mask.
1462 				 */
1463 				qc->flags |= ATA_QCFLAG_SENSE_VALID;
1464 			} else
1465 				qc->err_mask |= tmp;
1466 		}
1467 	}
1468 
1469 	if (qc->err_mask & (AC_ERR_HSM | AC_ERR_TIMEOUT | AC_ERR_ATA_BUS))
1470 		action |= ATA_EH_RESET;
1471 
1472 	return action;
1473 }
1474 
1475 static int ata_eh_categorize_error(unsigned int eflags, unsigned int err_mask,
1476 				   int *xfer_ok)
1477 {
1478 	int base = 0;
1479 
1480 	if (!(eflags & ATA_EFLAG_DUBIOUS_XFER))
1481 		*xfer_ok = 1;
1482 
1483 	if (!*xfer_ok)
1484 		base = ATA_ECAT_DUBIOUS_NONE;
1485 
1486 	if (err_mask & AC_ERR_ATA_BUS)
1487 		return base + ATA_ECAT_ATA_BUS;
1488 
1489 	if (err_mask & AC_ERR_TIMEOUT)
1490 		return base + ATA_ECAT_TOUT_HSM;
1491 
1492 	if (eflags & ATA_EFLAG_IS_IO) {
1493 		if (err_mask & AC_ERR_HSM)
1494 			return base + ATA_ECAT_TOUT_HSM;
1495 		if ((err_mask &
1496 		     (AC_ERR_DEV|AC_ERR_MEDIA|AC_ERR_INVALID)) == AC_ERR_DEV)
1497 			return base + ATA_ECAT_UNK_DEV;
1498 	}
1499 
1500 	return 0;
1501 }
1502 
1503 struct speed_down_verdict_arg {
1504 	u64 since;
1505 	int xfer_ok;
1506 	int nr_errors[ATA_ECAT_NR];
1507 };
1508 
1509 static int speed_down_verdict_cb(struct ata_ering_entry *ent, void *void_arg)
1510 {
1511 	struct speed_down_verdict_arg *arg = void_arg;
1512 	int cat;
1513 
1514 	if (ent->timestamp < arg->since)
1515 		return -1;
1516 
1517 	cat = ata_eh_categorize_error(ent->eflags, ent->err_mask,
1518 				      &arg->xfer_ok);
1519 	arg->nr_errors[cat]++;
1520 
1521 	return 0;
1522 }
1523 
1524 /**
1525  *	ata_eh_speed_down_verdict - Determine speed down verdict
1526  *	@dev: Device of interest
1527  *
1528  *	This function examines error ring of @dev and determines
1529  *	whether NCQ needs to be turned off, transfer speed should be
1530  *	stepped down, or falling back to PIO is necessary.
1531  *
1532  *	ECAT_ATA_BUS	: ATA_BUS error for any command
1533  *
1534  *	ECAT_TOUT_HSM	: TIMEOUT for any command or HSM violation for
1535  *			  IO commands
1536  *
1537  *	ECAT_UNK_DEV	: Unknown DEV error for IO commands
1538  *
1539  *	ECAT_DUBIOUS_*	: Identical to above three but occurred while
1540  *			  data transfer hasn't been verified.
1541  *
1542  *	Verdicts are
1543  *
1544  *	NCQ_OFF		: Turn off NCQ.
1545  *
1546  *	SPEED_DOWN	: Speed down transfer speed but don't fall back
1547  *			  to PIO.
1548  *
1549  *	FALLBACK_TO_PIO	: Fall back to PIO.
1550  *
1551  *	Even if multiple verdicts are returned, only one action is
1552  *	taken per error.  An action triggered by non-DUBIOUS errors
1553  *	clears ering, while one triggered by DUBIOUS_* errors doesn't.
1554  *	This is to expedite speed down decisions right after device is
1555  *	initially configured.
1556  *
1557  *	The followings are speed down rules.  #1 and #2 deal with
1558  *	DUBIOUS errors.
1559  *
1560  *	1. If more than one DUBIOUS_ATA_BUS or DUBIOUS_TOUT_HSM errors
1561  *	   occurred during last 5 mins, SPEED_DOWN and FALLBACK_TO_PIO.
1562  *
1563  *	2. If more than one DUBIOUS_TOUT_HSM or DUBIOUS_UNK_DEV errors
1564  *	   occurred during last 5 mins, NCQ_OFF.
1565  *
1566  *	3. If more than 8 ATA_BUS, TOUT_HSM or UNK_DEV errors
1567  *	   ocurred during last 5 mins, FALLBACK_TO_PIO
1568  *
1569  *	4. If more than 3 TOUT_HSM or UNK_DEV errors occurred
1570  *	   during last 10 mins, NCQ_OFF.
1571  *
1572  *	5. If more than 3 ATA_BUS or TOUT_HSM errors, or more than 6
1573  *	   UNK_DEV errors occurred during last 10 mins, SPEED_DOWN.
1574  *
1575  *	LOCKING:
1576  *	Inherited from caller.
1577  *
1578  *	RETURNS:
1579  *	OR of ATA_EH_SPDN_* flags.
1580  */
1581 static unsigned int ata_eh_speed_down_verdict(struct ata_device *dev)
1582 {
1583 	const u64 j5mins = 5LLU * 60 * HZ, j10mins = 10LLU * 60 * HZ;
1584 	u64 j64 = get_jiffies_64();
1585 	struct speed_down_verdict_arg arg;
1586 	unsigned int verdict = 0;
1587 
1588 	/* scan past 5 mins of error history */
1589 	memset(&arg, 0, sizeof(arg));
1590 	arg.since = j64 - min(j64, j5mins);
1591 	ata_ering_map(&dev->ering, speed_down_verdict_cb, &arg);
1592 
1593 	if (arg.nr_errors[ATA_ECAT_DUBIOUS_ATA_BUS] +
1594 	    arg.nr_errors[ATA_ECAT_DUBIOUS_TOUT_HSM] > 1)
1595 		verdict |= ATA_EH_SPDN_SPEED_DOWN |
1596 			ATA_EH_SPDN_FALLBACK_TO_PIO | ATA_EH_SPDN_KEEP_ERRORS;
1597 
1598 	if (arg.nr_errors[ATA_ECAT_DUBIOUS_TOUT_HSM] +
1599 	    arg.nr_errors[ATA_ECAT_DUBIOUS_UNK_DEV] > 1)
1600 		verdict |= ATA_EH_SPDN_NCQ_OFF | ATA_EH_SPDN_KEEP_ERRORS;
1601 
1602 	if (arg.nr_errors[ATA_ECAT_ATA_BUS] +
1603 	    arg.nr_errors[ATA_ECAT_TOUT_HSM] +
1604 	    arg.nr_errors[ATA_ECAT_UNK_DEV] > 6)
1605 		verdict |= ATA_EH_SPDN_FALLBACK_TO_PIO;
1606 
1607 	/* scan past 10 mins of error history */
1608 	memset(&arg, 0, sizeof(arg));
1609 	arg.since = j64 - min(j64, j10mins);
1610 	ata_ering_map(&dev->ering, speed_down_verdict_cb, &arg);
1611 
1612 	if (arg.nr_errors[ATA_ECAT_TOUT_HSM] +
1613 	    arg.nr_errors[ATA_ECAT_UNK_DEV] > 3)
1614 		verdict |= ATA_EH_SPDN_NCQ_OFF;
1615 
1616 	if (arg.nr_errors[ATA_ECAT_ATA_BUS] +
1617 	    arg.nr_errors[ATA_ECAT_TOUT_HSM] > 3 ||
1618 	    arg.nr_errors[ATA_ECAT_UNK_DEV] > 6)
1619 		verdict |= ATA_EH_SPDN_SPEED_DOWN;
1620 
1621 	return verdict;
1622 }
1623 
1624 /**
1625  *	ata_eh_speed_down - record error and speed down if necessary
1626  *	@dev: Failed device
1627  *	@eflags: mask of ATA_EFLAG_* flags
1628  *	@err_mask: err_mask of the error
1629  *
1630  *	Record error and examine error history to determine whether
1631  *	adjusting transmission speed is necessary.  It also sets
1632  *	transmission limits appropriately if such adjustment is
1633  *	necessary.
1634  *
1635  *	LOCKING:
1636  *	Kernel thread context (may sleep).
1637  *
1638  *	RETURNS:
1639  *	Determined recovery action.
1640  */
1641 static unsigned int ata_eh_speed_down(struct ata_device *dev,
1642 				unsigned int eflags, unsigned int err_mask)
1643 {
1644 	struct ata_link *link = dev->link;
1645 	int xfer_ok = 0;
1646 	unsigned int verdict;
1647 	unsigned int action = 0;
1648 
1649 	/* don't bother if Cat-0 error */
1650 	if (ata_eh_categorize_error(eflags, err_mask, &xfer_ok) == 0)
1651 		return 0;
1652 
1653 	/* record error and determine whether speed down is necessary */
1654 	ata_ering_record(&dev->ering, eflags, err_mask);
1655 	verdict = ata_eh_speed_down_verdict(dev);
1656 
1657 	/* turn off NCQ? */
1658 	if ((verdict & ATA_EH_SPDN_NCQ_OFF) &&
1659 	    (dev->flags & (ATA_DFLAG_PIO | ATA_DFLAG_NCQ |
1660 			   ATA_DFLAG_NCQ_OFF)) == ATA_DFLAG_NCQ) {
1661 		dev->flags |= ATA_DFLAG_NCQ_OFF;
1662 		ata_dev_printk(dev, KERN_WARNING,
1663 			       "NCQ disabled due to excessive errors\n");
1664 		goto done;
1665 	}
1666 
1667 	/* speed down? */
1668 	if (verdict & ATA_EH_SPDN_SPEED_DOWN) {
1669 		/* speed down SATA link speed if possible */
1670 		if (sata_down_spd_limit(link) == 0) {
1671 			action |= ATA_EH_RESET;
1672 			goto done;
1673 		}
1674 
1675 		/* lower transfer mode */
1676 		if (dev->spdn_cnt < 2) {
1677 			static const int dma_dnxfer_sel[] =
1678 				{ ATA_DNXFER_DMA, ATA_DNXFER_40C };
1679 			static const int pio_dnxfer_sel[] =
1680 				{ ATA_DNXFER_PIO, ATA_DNXFER_FORCE_PIO0 };
1681 			int sel;
1682 
1683 			if (dev->xfer_shift != ATA_SHIFT_PIO)
1684 				sel = dma_dnxfer_sel[dev->spdn_cnt];
1685 			else
1686 				sel = pio_dnxfer_sel[dev->spdn_cnt];
1687 
1688 			dev->spdn_cnt++;
1689 
1690 			if (ata_down_xfermask_limit(dev, sel) == 0) {
1691 				action |= ATA_EH_RESET;
1692 				goto done;
1693 			}
1694 		}
1695 	}
1696 
1697 	/* Fall back to PIO?  Slowing down to PIO is meaningless for
1698 	 * SATA ATA devices.  Consider it only for PATA and SATAPI.
1699 	 */
1700 	if ((verdict & ATA_EH_SPDN_FALLBACK_TO_PIO) && (dev->spdn_cnt >= 2) &&
1701 	    (link->ap->cbl != ATA_CBL_SATA || dev->class == ATA_DEV_ATAPI) &&
1702 	    (dev->xfer_shift != ATA_SHIFT_PIO)) {
1703 		if (ata_down_xfermask_limit(dev, ATA_DNXFER_FORCE_PIO) == 0) {
1704 			dev->spdn_cnt = 0;
1705 			action |= ATA_EH_RESET;
1706 			goto done;
1707 		}
1708 	}
1709 
1710 	return 0;
1711  done:
1712 	/* device has been slowed down, blow error history */
1713 	if (!(verdict & ATA_EH_SPDN_KEEP_ERRORS))
1714 		ata_ering_clear(&dev->ering);
1715 	return action;
1716 }
1717 
1718 /**
1719  *	ata_eh_link_autopsy - analyze error and determine recovery action
1720  *	@link: host link to perform autopsy on
1721  *
1722  *	Analyze why @link failed and determine which recovery actions
1723  *	are needed.  This function also sets more detailed AC_ERR_*
1724  *	values and fills sense data for ATAPI CHECK SENSE.
1725  *
1726  *	LOCKING:
1727  *	Kernel thread context (may sleep).
1728  */
1729 static void ata_eh_link_autopsy(struct ata_link *link)
1730 {
1731 	struct ata_port *ap = link->ap;
1732 	struct ata_eh_context *ehc = &link->eh_context;
1733 	struct ata_device *dev;
1734 	unsigned int all_err_mask = 0, eflags = 0;
1735 	int tag;
1736 	u32 serror;
1737 	int rc;
1738 
1739 	DPRINTK("ENTER\n");
1740 
1741 	if (ehc->i.flags & ATA_EHI_NO_AUTOPSY)
1742 		return;
1743 
1744 	/* obtain and analyze SError */
1745 	rc = sata_scr_read(link, SCR_ERROR, &serror);
1746 	if (rc == 0) {
1747 		ehc->i.serror |= serror;
1748 		ata_eh_analyze_serror(link);
1749 	} else if (rc != -EOPNOTSUPP) {
1750 		/* SError read failed, force reset and probing */
1751 		ehc->i.probe_mask |= ATA_ALL_DEVICES;
1752 		ehc->i.action |= ATA_EH_RESET;
1753 		ehc->i.err_mask |= AC_ERR_OTHER;
1754 	}
1755 
1756 	/* analyze NCQ failure */
1757 	ata_eh_analyze_ncq_error(link);
1758 
1759 	/* any real error trumps AC_ERR_OTHER */
1760 	if (ehc->i.err_mask & ~AC_ERR_OTHER)
1761 		ehc->i.err_mask &= ~AC_ERR_OTHER;
1762 
1763 	all_err_mask |= ehc->i.err_mask;
1764 
1765 	for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
1766 		struct ata_queued_cmd *qc = __ata_qc_from_tag(ap, tag);
1767 
1768 		if (!(qc->flags & ATA_QCFLAG_FAILED) || qc->dev->link != link)
1769 			continue;
1770 
1771 		/* inherit upper level err_mask */
1772 		qc->err_mask |= ehc->i.err_mask;
1773 
1774 		/* analyze TF */
1775 		ehc->i.action |= ata_eh_analyze_tf(qc, &qc->result_tf);
1776 
1777 		/* DEV errors are probably spurious in case of ATA_BUS error */
1778 		if (qc->err_mask & AC_ERR_ATA_BUS)
1779 			qc->err_mask &= ~(AC_ERR_DEV | AC_ERR_MEDIA |
1780 					  AC_ERR_INVALID);
1781 
1782 		/* any real error trumps unknown error */
1783 		if (qc->err_mask & ~AC_ERR_OTHER)
1784 			qc->err_mask &= ~AC_ERR_OTHER;
1785 
1786 		/* SENSE_VALID trumps dev/unknown error and revalidation */
1787 		if (qc->flags & ATA_QCFLAG_SENSE_VALID)
1788 			qc->err_mask &= ~(AC_ERR_DEV | AC_ERR_OTHER);
1789 
1790 		/* determine whether the command is worth retrying */
1791 		if (!(qc->err_mask & AC_ERR_INVALID) &&
1792 		    ((qc->flags & ATA_QCFLAG_IO) || qc->err_mask != AC_ERR_DEV))
1793 			qc->flags |= ATA_QCFLAG_RETRY;
1794 
1795 		/* accumulate error info */
1796 		ehc->i.dev = qc->dev;
1797 		all_err_mask |= qc->err_mask;
1798 		if (qc->flags & ATA_QCFLAG_IO)
1799 			eflags |= ATA_EFLAG_IS_IO;
1800 	}
1801 
1802 	/* enforce default EH actions */
1803 	if (ap->pflags & ATA_PFLAG_FROZEN ||
1804 	    all_err_mask & (AC_ERR_HSM | AC_ERR_TIMEOUT))
1805 		ehc->i.action |= ATA_EH_RESET;
1806 	else if (((eflags & ATA_EFLAG_IS_IO) && all_err_mask) ||
1807 		 (!(eflags & ATA_EFLAG_IS_IO) && (all_err_mask & ~AC_ERR_DEV)))
1808 		ehc->i.action |= ATA_EH_REVALIDATE;
1809 
1810 	/* If we have offending qcs and the associated failed device,
1811 	 * perform per-dev EH action only on the offending device.
1812 	 */
1813 	if (ehc->i.dev) {
1814 		ehc->i.dev_action[ehc->i.dev->devno] |=
1815 			ehc->i.action & ATA_EH_PERDEV_MASK;
1816 		ehc->i.action &= ~ATA_EH_PERDEV_MASK;
1817 	}
1818 
1819 	/* propagate timeout to host link */
1820 	if ((all_err_mask & AC_ERR_TIMEOUT) && !ata_is_host_link(link))
1821 		ap->link.eh_context.i.err_mask |= AC_ERR_TIMEOUT;
1822 
1823 	/* record error and consider speeding down */
1824 	dev = ehc->i.dev;
1825 	if (!dev && ((ata_link_max_devices(link) == 1 &&
1826 		      ata_dev_enabled(link->device))))
1827 	    dev = link->device;
1828 
1829 	if (dev) {
1830 		if (dev->flags & ATA_DFLAG_DUBIOUS_XFER)
1831 			eflags |= ATA_EFLAG_DUBIOUS_XFER;
1832 		ehc->i.action |= ata_eh_speed_down(dev, eflags, all_err_mask);
1833 	}
1834 
1835 	DPRINTK("EXIT\n");
1836 }
1837 
1838 /**
1839  *	ata_eh_autopsy - analyze error and determine recovery action
1840  *	@ap: host port to perform autopsy on
1841  *
1842  *	Analyze all links of @ap and determine why they failed and
1843  *	which recovery actions are needed.
1844  *
1845  *	LOCKING:
1846  *	Kernel thread context (may sleep).
1847  */
1848 void ata_eh_autopsy(struct ata_port *ap)
1849 {
1850 	struct ata_link *link;
1851 
1852 	ata_port_for_each_link(link, ap)
1853 		ata_eh_link_autopsy(link);
1854 
1855 	/* Autopsy of fanout ports can affect host link autopsy.
1856 	 * Perform host link autopsy last.
1857 	 */
1858 	if (sata_pmp_attached(ap))
1859 		ata_eh_link_autopsy(&ap->link);
1860 }
1861 
1862 /**
1863  *	ata_eh_link_report - report error handling to user
1864  *	@link: ATA link EH is going on
1865  *
1866  *	Report EH to user.
1867  *
1868  *	LOCKING:
1869  *	None.
1870  */
1871 static void ata_eh_link_report(struct ata_link *link)
1872 {
1873 	struct ata_port *ap = link->ap;
1874 	struct ata_eh_context *ehc = &link->eh_context;
1875 	const char *frozen, *desc;
1876 	char tries_buf[6];
1877 	int tag, nr_failed = 0;
1878 
1879 	if (ehc->i.flags & ATA_EHI_QUIET)
1880 		return;
1881 
1882 	desc = NULL;
1883 	if (ehc->i.desc[0] != '\0')
1884 		desc = ehc->i.desc;
1885 
1886 	for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
1887 		struct ata_queued_cmd *qc = __ata_qc_from_tag(ap, tag);
1888 
1889 		if (!(qc->flags & ATA_QCFLAG_FAILED) || qc->dev->link != link ||
1890 		    ((qc->flags & ATA_QCFLAG_QUIET) &&
1891 		     qc->err_mask == AC_ERR_DEV))
1892 			continue;
1893 		if (qc->flags & ATA_QCFLAG_SENSE_VALID && !qc->err_mask)
1894 			continue;
1895 
1896 		nr_failed++;
1897 	}
1898 
1899 	if (!nr_failed && !ehc->i.err_mask)
1900 		return;
1901 
1902 	frozen = "";
1903 	if (ap->pflags & ATA_PFLAG_FROZEN)
1904 		frozen = " frozen";
1905 
1906 	memset(tries_buf, 0, sizeof(tries_buf));
1907 	if (ap->eh_tries < ATA_EH_MAX_TRIES)
1908 		snprintf(tries_buf, sizeof(tries_buf) - 1, " t%d",
1909 			 ap->eh_tries);
1910 
1911 	if (ehc->i.dev) {
1912 		ata_dev_printk(ehc->i.dev, KERN_ERR, "exception Emask 0x%x "
1913 			       "SAct 0x%x SErr 0x%x action 0x%x%s%s\n",
1914 			       ehc->i.err_mask, link->sactive, ehc->i.serror,
1915 			       ehc->i.action, frozen, tries_buf);
1916 		if (desc)
1917 			ata_dev_printk(ehc->i.dev, KERN_ERR, "%s\n", desc);
1918 	} else {
1919 		ata_link_printk(link, KERN_ERR, "exception Emask 0x%x "
1920 				"SAct 0x%x SErr 0x%x action 0x%x%s%s\n",
1921 				ehc->i.err_mask, link->sactive, ehc->i.serror,
1922 				ehc->i.action, frozen, tries_buf);
1923 		if (desc)
1924 			ata_link_printk(link, KERN_ERR, "%s\n", desc);
1925 	}
1926 
1927 	if (ehc->i.serror)
1928 		ata_port_printk(ap, KERN_ERR,
1929 		  "SError: { %s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s}\n",
1930 		  ehc->i.serror & SERR_DATA_RECOVERED ? "RecovData " : "",
1931 		  ehc->i.serror & SERR_COMM_RECOVERED ? "RecovComm " : "",
1932 		  ehc->i.serror & SERR_DATA ? "UnrecovData " : "",
1933 		  ehc->i.serror & SERR_PERSISTENT ? "Persist " : "",
1934 		  ehc->i.serror & SERR_PROTOCOL ? "Proto " : "",
1935 		  ehc->i.serror & SERR_INTERNAL ? "HostInt " : "",
1936 		  ehc->i.serror & SERR_PHYRDY_CHG ? "PHYRdyChg " : "",
1937 		  ehc->i.serror & SERR_PHY_INT_ERR ? "PHYInt " : "",
1938 		  ehc->i.serror & SERR_COMM_WAKE ? "CommWake " : "",
1939 		  ehc->i.serror & SERR_10B_8B_ERR ? "10B8B " : "",
1940 		  ehc->i.serror & SERR_DISPARITY ? "Dispar " : "",
1941 		  ehc->i.serror & SERR_CRC ? "BadCRC " : "",
1942 		  ehc->i.serror & SERR_HANDSHAKE ? "Handshk " : "",
1943 		  ehc->i.serror & SERR_LINK_SEQ_ERR ? "LinkSeq " : "",
1944 		  ehc->i.serror & SERR_TRANS_ST_ERROR ? "TrStaTrns " : "",
1945 		  ehc->i.serror & SERR_UNRECOG_FIS ? "UnrecFIS " : "",
1946 		  ehc->i.serror & SERR_DEV_XCHG ? "DevExch " : "");
1947 
1948 	for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
1949 		struct ata_queued_cmd *qc = __ata_qc_from_tag(ap, tag);
1950 		struct ata_taskfile *cmd = &qc->tf, *res = &qc->result_tf;
1951 		const u8 *cdb = qc->cdb;
1952 		char data_buf[20] = "";
1953 		char cdb_buf[70] = "";
1954 
1955 		if (!(qc->flags & ATA_QCFLAG_FAILED) ||
1956 		    qc->dev->link != link || !qc->err_mask)
1957 			continue;
1958 
1959 		if (qc->dma_dir != DMA_NONE) {
1960 			static const char *dma_str[] = {
1961 				[DMA_BIDIRECTIONAL]	= "bidi",
1962 				[DMA_TO_DEVICE]		= "out",
1963 				[DMA_FROM_DEVICE]	= "in",
1964 			};
1965 			static const char *prot_str[] = {
1966 				[ATA_PROT_PIO]		= "pio",
1967 				[ATA_PROT_DMA]		= "dma",
1968 				[ATA_PROT_NCQ]		= "ncq",
1969 				[ATAPI_PROT_PIO]	= "pio",
1970 				[ATAPI_PROT_DMA]	= "dma",
1971 			};
1972 
1973 			snprintf(data_buf, sizeof(data_buf), " %s %u %s",
1974 				 prot_str[qc->tf.protocol], qc->nbytes,
1975 				 dma_str[qc->dma_dir]);
1976 		}
1977 
1978 		if (ata_is_atapi(qc->tf.protocol))
1979 			snprintf(cdb_buf, sizeof(cdb_buf),
1980 				 "cdb %02x %02x %02x %02x %02x %02x %02x %02x  "
1981 				 "%02x %02x %02x %02x %02x %02x %02x %02x\n         ",
1982 				 cdb[0], cdb[1], cdb[2], cdb[3],
1983 				 cdb[4], cdb[5], cdb[6], cdb[7],
1984 				 cdb[8], cdb[9], cdb[10], cdb[11],
1985 				 cdb[12], cdb[13], cdb[14], cdb[15]);
1986 
1987 		ata_dev_printk(qc->dev, KERN_ERR,
1988 			"cmd %02x/%02x:%02x:%02x:%02x:%02x/%02x:%02x:%02x:%02x:%02x/%02x "
1989 			"tag %d%s\n         %s"
1990 			"res %02x/%02x:%02x:%02x:%02x:%02x/%02x:%02x:%02x:%02x:%02x/%02x "
1991 			"Emask 0x%x (%s)%s\n",
1992 			cmd->command, cmd->feature, cmd->nsect,
1993 			cmd->lbal, cmd->lbam, cmd->lbah,
1994 			cmd->hob_feature, cmd->hob_nsect,
1995 			cmd->hob_lbal, cmd->hob_lbam, cmd->hob_lbah,
1996 			cmd->device, qc->tag, data_buf, cdb_buf,
1997 			res->command, res->feature, res->nsect,
1998 			res->lbal, res->lbam, res->lbah,
1999 			res->hob_feature, res->hob_nsect,
2000 			res->hob_lbal, res->hob_lbam, res->hob_lbah,
2001 			res->device, qc->err_mask, ata_err_string(qc->err_mask),
2002 			qc->err_mask & AC_ERR_NCQ ? " <F>" : "");
2003 
2004 		if (res->command & (ATA_BUSY | ATA_DRDY | ATA_DF | ATA_DRQ |
2005 				    ATA_ERR)) {
2006 			if (res->command & ATA_BUSY)
2007 				ata_dev_printk(qc->dev, KERN_ERR,
2008 				  "status: { Busy }\n");
2009 			else
2010 				ata_dev_printk(qc->dev, KERN_ERR,
2011 				  "status: { %s%s%s%s}\n",
2012 				  res->command & ATA_DRDY ? "DRDY " : "",
2013 				  res->command & ATA_DF ? "DF " : "",
2014 				  res->command & ATA_DRQ ? "DRQ " : "",
2015 				  res->command & ATA_ERR ? "ERR " : "");
2016 		}
2017 
2018 		if (cmd->command != ATA_CMD_PACKET &&
2019 		    (res->feature & (ATA_ICRC | ATA_UNC | ATA_IDNF |
2020 				     ATA_ABORTED)))
2021 			ata_dev_printk(qc->dev, KERN_ERR,
2022 			  "error: { %s%s%s%s}\n",
2023 			  res->feature & ATA_ICRC ? "ICRC " : "",
2024 			  res->feature & ATA_UNC ? "UNC " : "",
2025 			  res->feature & ATA_IDNF ? "IDNF " : "",
2026 			  res->feature & ATA_ABORTED ? "ABRT " : "");
2027 	}
2028 }
2029 
2030 /**
2031  *	ata_eh_report - report error handling to user
2032  *	@ap: ATA port to report EH about
2033  *
2034  *	Report EH to user.
2035  *
2036  *	LOCKING:
2037  *	None.
2038  */
2039 void ata_eh_report(struct ata_port *ap)
2040 {
2041 	struct ata_link *link;
2042 
2043 	__ata_port_for_each_link(link, ap)
2044 		ata_eh_link_report(link);
2045 }
2046 
2047 static int ata_do_reset(struct ata_link *link, ata_reset_fn_t reset,
2048 			unsigned int *classes, unsigned long deadline)
2049 {
2050 	struct ata_device *dev;
2051 
2052 	ata_link_for_each_dev(dev, link)
2053 		classes[dev->devno] = ATA_DEV_UNKNOWN;
2054 
2055 	return reset(link, classes, deadline);
2056 }
2057 
2058 static int ata_eh_followup_srst_needed(struct ata_link *link,
2059 				       int rc, int classify,
2060 				       const unsigned int *classes)
2061 {
2062 	if ((link->flags & ATA_LFLAG_NO_SRST) || ata_link_offline(link))
2063 		return 0;
2064 	if (rc == -EAGAIN) {
2065 		if (classify)
2066 			return 1;
2067 		rc = 0;
2068 	}
2069 	if (rc != 0)
2070 		return 0;
2071 	if (sata_pmp_supported(link->ap) && ata_is_host_link(link))
2072 		return 1;
2073 	return 0;
2074 }
2075 
2076 int ata_eh_reset(struct ata_link *link, int classify,
2077 		 ata_prereset_fn_t prereset, ata_reset_fn_t softreset,
2078 		 ata_reset_fn_t hardreset, ata_postreset_fn_t postreset)
2079 {
2080 	struct ata_port *ap = link->ap;
2081 	struct ata_eh_context *ehc = &link->eh_context;
2082 	unsigned int *classes = ehc->classes;
2083 	unsigned int lflags = link->flags;
2084 	int verbose = !(ehc->i.flags & ATA_EHI_QUIET);
2085 	int max_tries = 0, try = 0;
2086 	struct ata_device *dev;
2087 	unsigned long deadline, now;
2088 	ata_reset_fn_t reset;
2089 	unsigned long flags;
2090 	u32 sstatus;
2091 	int nr_known, rc;
2092 
2093 	/*
2094 	 * Prepare to reset
2095 	 */
2096 	while (ata_eh_reset_timeouts[max_tries] != ULONG_MAX)
2097 		max_tries++;
2098 
2099 	now = jiffies;
2100 	deadline = ata_deadline(ehc->last_reset, ATA_EH_RESET_COOL_DOWN);
2101 	if (time_before(now, deadline))
2102 		schedule_timeout_uninterruptible(deadline - now);
2103 
2104 	spin_lock_irqsave(ap->lock, flags);
2105 	ap->pflags |= ATA_PFLAG_RESETTING;
2106 	spin_unlock_irqrestore(ap->lock, flags);
2107 
2108 	ata_eh_about_to_do(link, NULL, ATA_EH_RESET);
2109 	ehc->last_reset = jiffies;
2110 
2111 	ata_link_for_each_dev(dev, link) {
2112 		/* If we issue an SRST then an ATA drive (not ATAPI)
2113 		 * may change configuration and be in PIO0 timing. If
2114 		 * we do a hard reset (or are coming from power on)
2115 		 * this is true for ATA or ATAPI. Until we've set a
2116 		 * suitable controller mode we should not touch the
2117 		 * bus as we may be talking too fast.
2118 		 */
2119 		dev->pio_mode = XFER_PIO_0;
2120 
2121 		/* If the controller has a pio mode setup function
2122 		 * then use it to set the chipset to rights. Don't
2123 		 * touch the DMA setup as that will be dealt with when
2124 		 * configuring devices.
2125 		 */
2126 		if (ap->ops->set_piomode)
2127 			ap->ops->set_piomode(ap, dev);
2128 	}
2129 
2130 	/* prefer hardreset */
2131 	reset = NULL;
2132 	ehc->i.action &= ~ATA_EH_RESET;
2133 	if (hardreset) {
2134 		reset = hardreset;
2135 		ehc->i.action = ATA_EH_HARDRESET;
2136 	} else if (softreset) {
2137 		reset = softreset;
2138 		ehc->i.action = ATA_EH_SOFTRESET;
2139 	}
2140 
2141 	if (prereset) {
2142 		rc = prereset(link,
2143 			      ata_deadline(jiffies, ATA_EH_PRERESET_TIMEOUT));
2144 		if (rc) {
2145 			if (rc == -ENOENT) {
2146 				ata_link_printk(link, KERN_DEBUG,
2147 						"port disabled. ignoring.\n");
2148 				ehc->i.action &= ~ATA_EH_RESET;
2149 
2150 				ata_link_for_each_dev(dev, link)
2151 					classes[dev->devno] = ATA_DEV_NONE;
2152 
2153 				rc = 0;
2154 			} else
2155 				ata_link_printk(link, KERN_ERR,
2156 					"prereset failed (errno=%d)\n", rc);
2157 			goto out;
2158 		}
2159 
2160 		/* prereset() might have cleared ATA_EH_RESET.  If so,
2161 		 * bang classes and return.
2162 		 */
2163 		if (reset && !(ehc->i.action & ATA_EH_RESET)) {
2164 			ata_link_for_each_dev(dev, link)
2165 				classes[dev->devno] = ATA_DEV_NONE;
2166 			rc = 0;
2167 			goto out;
2168 		}
2169 	}
2170 
2171  retry:
2172 	/*
2173 	 * Perform reset
2174 	 */
2175 	ehc->last_reset = jiffies;
2176 	if (ata_is_host_link(link))
2177 		ata_eh_freeze_port(ap);
2178 
2179 	deadline = ata_deadline(jiffies, ata_eh_reset_timeouts[try++]);
2180 
2181 	if (reset) {
2182 		if (verbose)
2183 			ata_link_printk(link, KERN_INFO, "%s resetting link\n",
2184 					reset == softreset ? "soft" : "hard");
2185 
2186 		/* mark that this EH session started with reset */
2187 		if (reset == hardreset)
2188 			ehc->i.flags |= ATA_EHI_DID_HARDRESET;
2189 		else
2190 			ehc->i.flags |= ATA_EHI_DID_SOFTRESET;
2191 
2192 		rc = ata_do_reset(link, reset, classes, deadline);
2193 
2194 		if (reset == hardreset &&
2195 		    ata_eh_followup_srst_needed(link, rc, classify, classes)) {
2196 			/* okay, let's do follow-up softreset */
2197 			reset = softreset;
2198 
2199 			if (!reset) {
2200 				ata_link_printk(link, KERN_ERR,
2201 						"follow-up softreset required "
2202 						"but no softreset avaliable\n");
2203 				rc = -EINVAL;
2204 				goto fail;
2205 			}
2206 
2207 			ata_eh_about_to_do(link, NULL, ATA_EH_RESET);
2208 			rc = ata_do_reset(link, reset, classes, deadline);
2209 		}
2210 
2211 		/* -EAGAIN can happen if we skipped followup SRST */
2212 		if (rc && rc != -EAGAIN)
2213 			goto fail;
2214 	} else {
2215 		if (verbose)
2216 			ata_link_printk(link, KERN_INFO, "no reset method "
2217 					"available, skipping reset\n");
2218 		if (!(lflags & ATA_LFLAG_ASSUME_CLASS))
2219 			lflags |= ATA_LFLAG_ASSUME_ATA;
2220 	}
2221 
2222 	/*
2223 	 * Post-reset processing
2224 	 */
2225 	ata_link_for_each_dev(dev, link) {
2226 		/* After the reset, the device state is PIO 0 and the
2227 		 * controller state is undefined.  Reset also wakes up
2228 		 * drives from sleeping mode.
2229 		 */
2230 		dev->pio_mode = XFER_PIO_0;
2231 		dev->flags &= ~ATA_DFLAG_SLEEPING;
2232 
2233 		if (ata_link_offline(link))
2234 			continue;
2235 
2236 		/* apply class override */
2237 		if (lflags & ATA_LFLAG_ASSUME_ATA)
2238 			classes[dev->devno] = ATA_DEV_ATA;
2239 		else if (lflags & ATA_LFLAG_ASSUME_SEMB)
2240 			classes[dev->devno] = ATA_DEV_SEMB_UNSUP; /* not yet */
2241 	}
2242 
2243 	/* record current link speed */
2244 	if (sata_scr_read(link, SCR_STATUS, &sstatus) == 0)
2245 		link->sata_spd = (sstatus >> 4) & 0xf;
2246 
2247 	/* thaw the port */
2248 	if (ata_is_host_link(link))
2249 		ata_eh_thaw_port(ap);
2250 
2251 	/* postreset() should clear hardware SError.  Although SError
2252 	 * is cleared during link resume, clearing SError here is
2253 	 * necessary as some PHYs raise hotplug events after SRST.
2254 	 * This introduces race condition where hotplug occurs between
2255 	 * reset and here.  This race is mediated by cross checking
2256 	 * link onlineness and classification result later.
2257 	 */
2258 	if (postreset)
2259 		postreset(link, classes);
2260 
2261 	/* clear cached SError */
2262 	spin_lock_irqsave(link->ap->lock, flags);
2263 	link->eh_info.serror = 0;
2264 	spin_unlock_irqrestore(link->ap->lock, flags);
2265 
2266 	/* Make sure onlineness and classification result correspond.
2267 	 * Hotplug could have happened during reset and some
2268 	 * controllers fail to wait while a drive is spinning up after
2269 	 * being hotplugged causing misdetection.  By cross checking
2270 	 * link onlineness and classification result, those conditions
2271 	 * can be reliably detected and retried.
2272 	 */
2273 	nr_known = 0;
2274 	ata_link_for_each_dev(dev, link) {
2275 		/* convert all ATA_DEV_UNKNOWN to ATA_DEV_NONE */
2276 		if (classes[dev->devno] == ATA_DEV_UNKNOWN)
2277 			classes[dev->devno] = ATA_DEV_NONE;
2278 		else
2279 			nr_known++;
2280 	}
2281 
2282 	if (classify && !nr_known && ata_link_online(link)) {
2283 		if (try < max_tries) {
2284 			ata_link_printk(link, KERN_WARNING, "link online but "
2285 				       "device misclassified, retrying\n");
2286 			rc = -EAGAIN;
2287 			goto fail;
2288 		}
2289 		ata_link_printk(link, KERN_WARNING,
2290 			       "link online but device misclassified, "
2291 			       "device detection might fail\n");
2292 	}
2293 
2294 	/* reset successful, schedule revalidation */
2295 	ata_eh_done(link, NULL, ATA_EH_RESET);
2296 	ehc->last_reset = jiffies;
2297 	ehc->i.action |= ATA_EH_REVALIDATE;
2298 
2299 	rc = 0;
2300  out:
2301 	/* clear hotplug flag */
2302 	ehc->i.flags &= ~ATA_EHI_HOTPLUGGED;
2303 
2304 	spin_lock_irqsave(ap->lock, flags);
2305 	ap->pflags &= ~ATA_PFLAG_RESETTING;
2306 	spin_unlock_irqrestore(ap->lock, flags);
2307 
2308 	return rc;
2309 
2310  fail:
2311 	/* if SCR isn't accessible on a fan-out port, PMP needs to be reset */
2312 	if (!ata_is_host_link(link) &&
2313 	    sata_scr_read(link, SCR_STATUS, &sstatus))
2314 		rc = -ERESTART;
2315 
2316 	if (rc == -ERESTART || try >= max_tries)
2317 		goto out;
2318 
2319 	now = jiffies;
2320 	if (time_before(now, deadline)) {
2321 		unsigned long delta = deadline - now;
2322 
2323 		ata_link_printk(link, KERN_WARNING,
2324 			"reset failed (errno=%d), retrying in %u secs\n",
2325 			rc, DIV_ROUND_UP(jiffies_to_msecs(delta), 1000));
2326 
2327 		while (delta)
2328 			delta = schedule_timeout_uninterruptible(delta);
2329 	}
2330 
2331 	if (rc == -EPIPE || try == max_tries - 1)
2332 		sata_down_spd_limit(link);
2333 	if (hardreset)
2334 		reset = hardreset;
2335 	goto retry;
2336 }
2337 
2338 static int ata_eh_revalidate_and_attach(struct ata_link *link,
2339 					struct ata_device **r_failed_dev)
2340 {
2341 	struct ata_port *ap = link->ap;
2342 	struct ata_eh_context *ehc = &link->eh_context;
2343 	struct ata_device *dev;
2344 	unsigned int new_mask = 0;
2345 	unsigned long flags;
2346 	int rc = 0;
2347 
2348 	DPRINTK("ENTER\n");
2349 
2350 	/* For PATA drive side cable detection to work, IDENTIFY must
2351 	 * be done backwards such that PDIAG- is released by the slave
2352 	 * device before the master device is identified.
2353 	 */
2354 	ata_link_for_each_dev_reverse(dev, link) {
2355 		unsigned int action = ata_eh_dev_action(dev);
2356 		unsigned int readid_flags = 0;
2357 
2358 		if (ehc->i.flags & ATA_EHI_DID_RESET)
2359 			readid_flags |= ATA_READID_POSTRESET;
2360 
2361 		if ((action & ATA_EH_REVALIDATE) && ata_dev_enabled(dev)) {
2362 			WARN_ON(dev->class == ATA_DEV_PMP);
2363 
2364 			if (ata_link_offline(link)) {
2365 				rc = -EIO;
2366 				goto err;
2367 			}
2368 
2369 			ata_eh_about_to_do(link, dev, ATA_EH_REVALIDATE);
2370 			rc = ata_dev_revalidate(dev, ehc->classes[dev->devno],
2371 						readid_flags);
2372 			if (rc)
2373 				goto err;
2374 
2375 			ata_eh_done(link, dev, ATA_EH_REVALIDATE);
2376 
2377 			/* Configuration may have changed, reconfigure
2378 			 * transfer mode.
2379 			 */
2380 			ehc->i.flags |= ATA_EHI_SETMODE;
2381 
2382 			/* schedule the scsi_rescan_device() here */
2383 			queue_work(ata_aux_wq, &(ap->scsi_rescan_task));
2384 		} else if (dev->class == ATA_DEV_UNKNOWN &&
2385 			   ehc->tries[dev->devno] &&
2386 			   ata_class_enabled(ehc->classes[dev->devno])) {
2387 			dev->class = ehc->classes[dev->devno];
2388 
2389 			if (dev->class == ATA_DEV_PMP)
2390 				rc = sata_pmp_attach(dev);
2391 			else
2392 				rc = ata_dev_read_id(dev, &dev->class,
2393 						     readid_flags, dev->id);
2394 			switch (rc) {
2395 			case 0:
2396 				new_mask |= 1 << dev->devno;
2397 				break;
2398 			case -ENOENT:
2399 				/* IDENTIFY was issued to non-existent
2400 				 * device.  No need to reset.  Just
2401 				 * thaw and kill the device.
2402 				 */
2403 				ata_eh_thaw_port(ap);
2404 				dev->class = ATA_DEV_UNKNOWN;
2405 				break;
2406 			default:
2407 				dev->class = ATA_DEV_UNKNOWN;
2408 				goto err;
2409 			}
2410 		}
2411 	}
2412 
2413 	/* PDIAG- should have been released, ask cable type if post-reset */
2414 	if ((ehc->i.flags & ATA_EHI_DID_RESET) && ata_is_host_link(link)) {
2415 		if (ap->ops->cable_detect)
2416 			ap->cbl = ap->ops->cable_detect(ap);
2417 		ata_force_cbl(ap);
2418 	}
2419 
2420 	/* Configure new devices forward such that user doesn't see
2421 	 * device detection messages backwards.
2422 	 */
2423 	ata_link_for_each_dev(dev, link) {
2424 		if (!(new_mask & (1 << dev->devno)) ||
2425 		    dev->class == ATA_DEV_PMP)
2426 			continue;
2427 
2428 		ehc->i.flags |= ATA_EHI_PRINTINFO;
2429 		rc = ata_dev_configure(dev);
2430 		ehc->i.flags &= ~ATA_EHI_PRINTINFO;
2431 		if (rc)
2432 			goto err;
2433 
2434 		spin_lock_irqsave(ap->lock, flags);
2435 		ap->pflags |= ATA_PFLAG_SCSI_HOTPLUG;
2436 		spin_unlock_irqrestore(ap->lock, flags);
2437 
2438 		/* new device discovered, configure xfermode */
2439 		ehc->i.flags |= ATA_EHI_SETMODE;
2440 	}
2441 
2442 	return 0;
2443 
2444  err:
2445 	*r_failed_dev = dev;
2446 	DPRINTK("EXIT rc=%d\n", rc);
2447 	return rc;
2448 }
2449 
2450 /**
2451  *	ata_set_mode - Program timings and issue SET FEATURES - XFER
2452  *	@link: link on which timings will be programmed
2453  *	@r_failed_dev: out paramter for failed device
2454  *
2455  *	Set ATA device disk transfer mode (PIO3, UDMA6, etc.).  If
2456  *	ata_set_mode() fails, pointer to the failing device is
2457  *	returned in @r_failed_dev.
2458  *
2459  *	LOCKING:
2460  *	PCI/etc. bus probe sem.
2461  *
2462  *	RETURNS:
2463  *	0 on success, negative errno otherwise
2464  */
2465 int ata_set_mode(struct ata_link *link, struct ata_device **r_failed_dev)
2466 {
2467 	struct ata_port *ap = link->ap;
2468 	struct ata_device *dev;
2469 	int rc;
2470 
2471 	/* if data transfer is verified, clear DUBIOUS_XFER on ering top */
2472 	ata_link_for_each_dev(dev, link) {
2473 		if (!(dev->flags & ATA_DFLAG_DUBIOUS_XFER)) {
2474 			struct ata_ering_entry *ent;
2475 
2476 			ent = ata_ering_top(&dev->ering);
2477 			if (ent)
2478 				ent->eflags &= ~ATA_EFLAG_DUBIOUS_XFER;
2479 		}
2480 	}
2481 
2482 	/* has private set_mode? */
2483 	if (ap->ops->set_mode)
2484 		rc = ap->ops->set_mode(link, r_failed_dev);
2485 	else
2486 		rc = ata_do_set_mode(link, r_failed_dev);
2487 
2488 	/* if transfer mode has changed, set DUBIOUS_XFER on device */
2489 	ata_link_for_each_dev(dev, link) {
2490 		struct ata_eh_context *ehc = &link->eh_context;
2491 		u8 saved_xfer_mode = ehc->saved_xfer_mode[dev->devno];
2492 		u8 saved_ncq = !!(ehc->saved_ncq_enabled & (1 << dev->devno));
2493 
2494 		if (dev->xfer_mode != saved_xfer_mode ||
2495 		    ata_ncq_enabled(dev) != saved_ncq)
2496 			dev->flags |= ATA_DFLAG_DUBIOUS_XFER;
2497 	}
2498 
2499 	return rc;
2500 }
2501 
2502 static int ata_link_nr_enabled(struct ata_link *link)
2503 {
2504 	struct ata_device *dev;
2505 	int cnt = 0;
2506 
2507 	ata_link_for_each_dev(dev, link)
2508 		if (ata_dev_enabled(dev))
2509 			cnt++;
2510 	return cnt;
2511 }
2512 
2513 static int ata_link_nr_vacant(struct ata_link *link)
2514 {
2515 	struct ata_device *dev;
2516 	int cnt = 0;
2517 
2518 	ata_link_for_each_dev(dev, link)
2519 		if (dev->class == ATA_DEV_UNKNOWN)
2520 			cnt++;
2521 	return cnt;
2522 }
2523 
2524 static int ata_eh_skip_recovery(struct ata_link *link)
2525 {
2526 	struct ata_port *ap = link->ap;
2527 	struct ata_eh_context *ehc = &link->eh_context;
2528 	struct ata_device *dev;
2529 
2530 	/* skip disabled links */
2531 	if (link->flags & ATA_LFLAG_DISABLED)
2532 		return 1;
2533 
2534 	/* thaw frozen port and recover failed devices */
2535 	if ((ap->pflags & ATA_PFLAG_FROZEN) || ata_link_nr_enabled(link))
2536 		return 0;
2537 
2538 	/* reset at least once if reset is requested */
2539 	if ((ehc->i.action & ATA_EH_RESET) &&
2540 	    !(ehc->i.flags & ATA_EHI_DID_RESET))
2541 		return 0;
2542 
2543 	/* skip if class codes for all vacant slots are ATA_DEV_NONE */
2544 	ata_link_for_each_dev(dev, link) {
2545 		if (dev->class == ATA_DEV_UNKNOWN &&
2546 		    ehc->classes[dev->devno] != ATA_DEV_NONE)
2547 			return 0;
2548 	}
2549 
2550 	return 1;
2551 }
2552 
2553 static int ata_eh_schedule_probe(struct ata_device *dev)
2554 {
2555 	struct ata_eh_context *ehc = &dev->link->eh_context;
2556 
2557 	if (!(ehc->i.probe_mask & (1 << dev->devno)) ||
2558 	    (ehc->did_probe_mask & (1 << dev->devno)))
2559 		return 0;
2560 
2561 	ata_eh_detach_dev(dev);
2562 	ata_dev_init(dev);
2563 	ehc->did_probe_mask |= (1 << dev->devno);
2564 	ehc->i.action |= ATA_EH_RESET;
2565 	ehc->saved_xfer_mode[dev->devno] = 0;
2566 	ehc->saved_ncq_enabled &= ~(1 << dev->devno);
2567 
2568 	return 1;
2569 }
2570 
2571 static int ata_eh_handle_dev_fail(struct ata_device *dev, int err)
2572 {
2573 	struct ata_eh_context *ehc = &dev->link->eh_context;
2574 
2575 	ehc->tries[dev->devno]--;
2576 
2577 	switch (err) {
2578 	case -ENODEV:
2579 		/* device missing or wrong IDENTIFY data, schedule probing */
2580 		ehc->i.probe_mask |= (1 << dev->devno);
2581 	case -EINVAL:
2582 		/* give it just one more chance */
2583 		ehc->tries[dev->devno] = min(ehc->tries[dev->devno], 1);
2584 	case -EIO:
2585 		if (ehc->tries[dev->devno] == 1 && dev->pio_mode > XFER_PIO_0) {
2586 			/* This is the last chance, better to slow
2587 			 * down than lose it.
2588 			 */
2589 			sata_down_spd_limit(dev->link);
2590 			ata_down_xfermask_limit(dev, ATA_DNXFER_PIO);
2591 		}
2592 	}
2593 
2594 	if (ata_dev_enabled(dev) && !ehc->tries[dev->devno]) {
2595 		/* disable device if it has used up all its chances */
2596 		ata_dev_disable(dev);
2597 
2598 		/* detach if offline */
2599 		if (ata_link_offline(dev->link))
2600 			ata_eh_detach_dev(dev);
2601 
2602 		/* schedule probe if necessary */
2603 		if (ata_eh_schedule_probe(dev))
2604 			ehc->tries[dev->devno] = ATA_EH_DEV_TRIES;
2605 
2606 		return 1;
2607 	} else {
2608 		ehc->i.action |= ATA_EH_RESET;
2609 		return 0;
2610 	}
2611 }
2612 
2613 /**
2614  *	ata_eh_recover - recover host port after error
2615  *	@ap: host port to recover
2616  *	@prereset: prereset method (can be NULL)
2617  *	@softreset: softreset method (can be NULL)
2618  *	@hardreset: hardreset method (can be NULL)
2619  *	@postreset: postreset method (can be NULL)
2620  *	@r_failed_link: out parameter for failed link
2621  *
2622  *	This is the alpha and omega, eum and yang, heart and soul of
2623  *	libata exception handling.  On entry, actions required to
2624  *	recover each link and hotplug requests are recorded in the
2625  *	link's eh_context.  This function executes all the operations
2626  *	with appropriate retrials and fallbacks to resurrect failed
2627  *	devices, detach goners and greet newcomers.
2628  *
2629  *	LOCKING:
2630  *	Kernel thread context (may sleep).
2631  *
2632  *	RETURNS:
2633  *	0 on success, -errno on failure.
2634  */
2635 int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
2636 		   ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
2637 		   ata_postreset_fn_t postreset,
2638 		   struct ata_link **r_failed_link)
2639 {
2640 	struct ata_link *link;
2641 	struct ata_device *dev;
2642 	int nr_failed_devs;
2643 	int rc;
2644 	unsigned long flags;
2645 
2646 	DPRINTK("ENTER\n");
2647 
2648 	/* prep for recovery */
2649 	ata_port_for_each_link(link, ap) {
2650 		struct ata_eh_context *ehc = &link->eh_context;
2651 
2652 		/* re-enable link? */
2653 		if (ehc->i.action & ATA_EH_ENABLE_LINK) {
2654 			ata_eh_about_to_do(link, NULL, ATA_EH_ENABLE_LINK);
2655 			spin_lock_irqsave(ap->lock, flags);
2656 			link->flags &= ~ATA_LFLAG_DISABLED;
2657 			spin_unlock_irqrestore(ap->lock, flags);
2658 			ata_eh_done(link, NULL, ATA_EH_ENABLE_LINK);
2659 		}
2660 
2661 		ata_link_for_each_dev(dev, link) {
2662 			if (link->flags & ATA_LFLAG_NO_RETRY)
2663 				ehc->tries[dev->devno] = 1;
2664 			else
2665 				ehc->tries[dev->devno] = ATA_EH_DEV_TRIES;
2666 
2667 			/* collect port action mask recorded in dev actions */
2668 			ehc->i.action |= ehc->i.dev_action[dev->devno] &
2669 					 ~ATA_EH_PERDEV_MASK;
2670 			ehc->i.dev_action[dev->devno] &= ATA_EH_PERDEV_MASK;
2671 
2672 			/* process hotplug request */
2673 			if (dev->flags & ATA_DFLAG_DETACH)
2674 				ata_eh_detach_dev(dev);
2675 
2676 			/* schedule probe if necessary */
2677 			if (!ata_dev_enabled(dev))
2678 				ata_eh_schedule_probe(dev);
2679 		}
2680 	}
2681 
2682  retry:
2683 	rc = 0;
2684 	nr_failed_devs = 0;
2685 
2686 	/* if UNLOADING, finish immediately */
2687 	if (ap->pflags & ATA_PFLAG_UNLOADING)
2688 		goto out;
2689 
2690 	/* prep for EH */
2691 	ata_port_for_each_link(link, ap) {
2692 		struct ata_eh_context *ehc = &link->eh_context;
2693 
2694 		/* skip EH if possible. */
2695 		if (ata_eh_skip_recovery(link))
2696 			ehc->i.action = 0;
2697 
2698 		ata_link_for_each_dev(dev, link)
2699 			ehc->classes[dev->devno] = ATA_DEV_UNKNOWN;
2700 	}
2701 
2702 	/* reset */
2703 	ata_port_for_each_link(link, ap) {
2704 		struct ata_eh_context *ehc = &link->eh_context;
2705 
2706 		if (!(ehc->i.action & ATA_EH_RESET))
2707 			continue;
2708 
2709 		rc = ata_eh_reset(link, ata_link_nr_vacant(link),
2710 				  prereset, softreset, hardreset, postreset);
2711 		if (rc) {
2712 			ata_link_printk(link, KERN_ERR,
2713 					"reset failed, giving up\n");
2714 			goto out;
2715 		}
2716 	}
2717 
2718 	/* the rest */
2719 	ata_port_for_each_link(link, ap) {
2720 		struct ata_eh_context *ehc = &link->eh_context;
2721 
2722 		/* revalidate existing devices and attach new ones */
2723 		rc = ata_eh_revalidate_and_attach(link, &dev);
2724 		if (rc)
2725 			goto dev_fail;
2726 
2727 		/* if PMP got attached, return, pmp EH will take care of it */
2728 		if (link->device->class == ATA_DEV_PMP) {
2729 			ehc->i.action = 0;
2730 			return 0;
2731 		}
2732 
2733 		/* configure transfer mode if necessary */
2734 		if (ehc->i.flags & ATA_EHI_SETMODE) {
2735 			rc = ata_set_mode(link, &dev);
2736 			if (rc)
2737 				goto dev_fail;
2738 			ehc->i.flags &= ~ATA_EHI_SETMODE;
2739 		}
2740 
2741 		if (ehc->i.action & ATA_EH_LPM)
2742 			ata_link_for_each_dev(dev, link)
2743 				ata_dev_enable_pm(dev, ap->pm_policy);
2744 
2745 		/* this link is okay now */
2746 		ehc->i.flags = 0;
2747 		continue;
2748 
2749 dev_fail:
2750 		nr_failed_devs++;
2751 		ata_eh_handle_dev_fail(dev, rc);
2752 
2753 		if (ap->pflags & ATA_PFLAG_FROZEN) {
2754 			/* PMP reset requires working host port.
2755 			 * Can't retry if it's frozen.
2756 			 */
2757 			if (sata_pmp_attached(ap))
2758 				goto out;
2759 			break;
2760 		}
2761 	}
2762 
2763 	if (nr_failed_devs)
2764 		goto retry;
2765 
2766  out:
2767 	if (rc && r_failed_link)
2768 		*r_failed_link = link;
2769 
2770 	DPRINTK("EXIT, rc=%d\n", rc);
2771 	return rc;
2772 }
2773 
2774 /**
2775  *	ata_eh_finish - finish up EH
2776  *	@ap: host port to finish EH for
2777  *
2778  *	Recovery is complete.  Clean up EH states and retry or finish
2779  *	failed qcs.
2780  *
2781  *	LOCKING:
2782  *	None.
2783  */
2784 void ata_eh_finish(struct ata_port *ap)
2785 {
2786 	int tag;
2787 
2788 	/* retry or finish qcs */
2789 	for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
2790 		struct ata_queued_cmd *qc = __ata_qc_from_tag(ap, tag);
2791 
2792 		if (!(qc->flags & ATA_QCFLAG_FAILED))
2793 			continue;
2794 
2795 		if (qc->err_mask) {
2796 			/* FIXME: Once EH migration is complete,
2797 			 * generate sense data in this function,
2798 			 * considering both err_mask and tf.
2799 			 */
2800 			if (qc->flags & ATA_QCFLAG_RETRY)
2801 				ata_eh_qc_retry(qc);
2802 			else
2803 				ata_eh_qc_complete(qc);
2804 		} else {
2805 			if (qc->flags & ATA_QCFLAG_SENSE_VALID) {
2806 				ata_eh_qc_complete(qc);
2807 			} else {
2808 				/* feed zero TF to sense generation */
2809 				memset(&qc->result_tf, 0, sizeof(qc->result_tf));
2810 				ata_eh_qc_retry(qc);
2811 			}
2812 		}
2813 	}
2814 
2815 	/* make sure nr_active_links is zero after EH */
2816 	WARN_ON(ap->nr_active_links);
2817 	ap->nr_active_links = 0;
2818 }
2819 
2820 /**
2821  *	ata_do_eh - do standard error handling
2822  *	@ap: host port to handle error for
2823  *
2824  *	@prereset: prereset method (can be NULL)
2825  *	@softreset: softreset method (can be NULL)
2826  *	@hardreset: hardreset method (can be NULL)
2827  *	@postreset: postreset method (can be NULL)
2828  *
2829  *	Perform standard error handling sequence.
2830  *
2831  *	LOCKING:
2832  *	Kernel thread context (may sleep).
2833  */
2834 void ata_do_eh(struct ata_port *ap, ata_prereset_fn_t prereset,
2835 	       ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
2836 	       ata_postreset_fn_t postreset)
2837 {
2838 	struct ata_device *dev;
2839 	int rc;
2840 
2841 	ata_eh_autopsy(ap);
2842 	ata_eh_report(ap);
2843 
2844 	rc = ata_eh_recover(ap, prereset, softreset, hardreset, postreset,
2845 			    NULL);
2846 	if (rc) {
2847 		ata_link_for_each_dev(dev, &ap->link)
2848 			ata_dev_disable(dev);
2849 	}
2850 
2851 	ata_eh_finish(ap);
2852 }
2853 
2854 /**
2855  *	ata_std_error_handler - standard error handler
2856  *	@ap: host port to handle error for
2857  *
2858  *	Standard error handler
2859  *
2860  *	LOCKING:
2861  *	Kernel thread context (may sleep).
2862  */
2863 void ata_std_error_handler(struct ata_port *ap)
2864 {
2865 	struct ata_port_operations *ops = ap->ops;
2866 	ata_reset_fn_t hardreset = ops->hardreset;
2867 
2868 	/* ignore built-in hardreset if SCR access is not available */
2869 	if (ata_is_builtin_hardreset(hardreset) && !sata_scr_valid(&ap->link))
2870 		hardreset = NULL;
2871 
2872 	ata_do_eh(ap, ops->prereset, ops->softreset, hardreset, ops->postreset);
2873 }
2874 
2875 #ifdef CONFIG_PM
2876 /**
2877  *	ata_eh_handle_port_suspend - perform port suspend operation
2878  *	@ap: port to suspend
2879  *
2880  *	Suspend @ap.
2881  *
2882  *	LOCKING:
2883  *	Kernel thread context (may sleep).
2884  */
2885 static void ata_eh_handle_port_suspend(struct ata_port *ap)
2886 {
2887 	unsigned long flags;
2888 	int rc = 0;
2889 
2890 	/* are we suspending? */
2891 	spin_lock_irqsave(ap->lock, flags);
2892 	if (!(ap->pflags & ATA_PFLAG_PM_PENDING) ||
2893 	    ap->pm_mesg.event == PM_EVENT_ON) {
2894 		spin_unlock_irqrestore(ap->lock, flags);
2895 		return;
2896 	}
2897 	spin_unlock_irqrestore(ap->lock, flags);
2898 
2899 	WARN_ON(ap->pflags & ATA_PFLAG_SUSPENDED);
2900 
2901 	/* tell ACPI we're suspending */
2902 	rc = ata_acpi_on_suspend(ap);
2903 	if (rc)
2904 		goto out;
2905 
2906 	/* suspend */
2907 	ata_eh_freeze_port(ap);
2908 
2909 	if (ap->ops->port_suspend)
2910 		rc = ap->ops->port_suspend(ap, ap->pm_mesg);
2911 
2912 	ata_acpi_set_state(ap, PMSG_SUSPEND);
2913  out:
2914 	/* report result */
2915 	spin_lock_irqsave(ap->lock, flags);
2916 
2917 	ap->pflags &= ~ATA_PFLAG_PM_PENDING;
2918 	if (rc == 0)
2919 		ap->pflags |= ATA_PFLAG_SUSPENDED;
2920 	else if (ap->pflags & ATA_PFLAG_FROZEN)
2921 		ata_port_schedule_eh(ap);
2922 
2923 	if (ap->pm_result) {
2924 		*ap->pm_result = rc;
2925 		ap->pm_result = NULL;
2926 	}
2927 
2928 	spin_unlock_irqrestore(ap->lock, flags);
2929 
2930 	return;
2931 }
2932 
2933 /**
2934  *	ata_eh_handle_port_resume - perform port resume operation
2935  *	@ap: port to resume
2936  *
2937  *	Resume @ap.
2938  *
2939  *	LOCKING:
2940  *	Kernel thread context (may sleep).
2941  */
2942 static void ata_eh_handle_port_resume(struct ata_port *ap)
2943 {
2944 	unsigned long flags;
2945 	int rc = 0;
2946 
2947 	/* are we resuming? */
2948 	spin_lock_irqsave(ap->lock, flags);
2949 	if (!(ap->pflags & ATA_PFLAG_PM_PENDING) ||
2950 	    ap->pm_mesg.event != PM_EVENT_ON) {
2951 		spin_unlock_irqrestore(ap->lock, flags);
2952 		return;
2953 	}
2954 	spin_unlock_irqrestore(ap->lock, flags);
2955 
2956 	WARN_ON(!(ap->pflags & ATA_PFLAG_SUSPENDED));
2957 
2958 	ata_acpi_set_state(ap, PMSG_ON);
2959 
2960 	if (ap->ops->port_resume)
2961 		rc = ap->ops->port_resume(ap);
2962 
2963 	/* tell ACPI that we're resuming */
2964 	ata_acpi_on_resume(ap);
2965 
2966 	/* report result */
2967 	spin_lock_irqsave(ap->lock, flags);
2968 	ap->pflags &= ~(ATA_PFLAG_PM_PENDING | ATA_PFLAG_SUSPENDED);
2969 	if (ap->pm_result) {
2970 		*ap->pm_result = rc;
2971 		ap->pm_result = NULL;
2972 	}
2973 	spin_unlock_irqrestore(ap->lock, flags);
2974 }
2975 #endif /* CONFIG_PM */
2976