xref: /linux/drivers/ata/libata-eh.c (revision 6feb348783767e3f38d7612e6551ee8b580ac4e9)
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/blkdev.h>
37 #include <linux/pci.h>
38 #include <scsi/scsi.h>
39 #include <scsi/scsi_host.h>
40 #include <scsi/scsi_eh.h>
41 #include <scsi/scsi_device.h>
42 #include <scsi/scsi_cmnd.h>
43 #include "../scsi/scsi_transport_api.h"
44 
45 #include <linux/libata.h>
46 
47 #include "libata.h"
48 
49 enum {
50 	/* speed down verdicts */
51 	ATA_EH_SPDN_NCQ_OFF		= (1 << 0),
52 	ATA_EH_SPDN_SPEED_DOWN		= (1 << 1),
53 	ATA_EH_SPDN_FALLBACK_TO_PIO	= (1 << 2),
54 	ATA_EH_SPDN_KEEP_ERRORS		= (1 << 3),
55 
56 	/* error flags */
57 	ATA_EFLAG_IS_IO			= (1 << 0),
58 	ATA_EFLAG_DUBIOUS_XFER		= (1 << 1),
59 
60 	/* error categories */
61 	ATA_ECAT_NONE			= 0,
62 	ATA_ECAT_ATA_BUS		= 1,
63 	ATA_ECAT_TOUT_HSM		= 2,
64 	ATA_ECAT_UNK_DEV		= 3,
65 	ATA_ECAT_DUBIOUS_NONE		= 4,
66 	ATA_ECAT_DUBIOUS_ATA_BUS	= 5,
67 	ATA_ECAT_DUBIOUS_TOUT_HSM	= 6,
68 	ATA_ECAT_DUBIOUS_UNK_DEV	= 7,
69 	ATA_ECAT_NR			= 8,
70 
71 	ATA_EH_CMD_DFL_TIMEOUT		=  5000,
72 
73 	/* always put at least this amount of time between resets */
74 	ATA_EH_RESET_COOL_DOWN		=  5000,
75 
76 	/* Waiting in ->prereset can never be reliable.  It's
77 	 * sometimes nice to wait there but it can't be depended upon;
78 	 * otherwise, we wouldn't be resetting.  Just give it enough
79 	 * time for most drives to spin up.
80 	 */
81 	ATA_EH_PRERESET_TIMEOUT		= 10000,
82 	ATA_EH_FASTDRAIN_INTERVAL	=  3000,
83 
84 	ATA_EH_UA_TRIES			= 5,
85 };
86 
87 /* The following table determines how we sequence resets.  Each entry
88  * represents timeout for that try.  The first try can be soft or
89  * hardreset.  All others are hardreset if available.  In most cases
90  * the first reset w/ 10sec timeout should succeed.  Following entries
91  * are mostly for error handling, hotplug and retarded devices.
92  */
93 static const unsigned long ata_eh_reset_timeouts[] = {
94 	10000,	/* most drives spin up by 10sec */
95 	10000,	/* > 99% working drives spin up before 20sec */
96 	35000,	/* give > 30 secs of idleness for retarded devices */
97 	 5000,	/* and sweet one last chance */
98 	ULONG_MAX, /* > 1 min has elapsed, give up */
99 };
100 
101 static const unsigned long ata_eh_identify_timeouts[] = {
102 	 5000,	/* covers > 99% of successes and not too boring on failures */
103 	10000,  /* combined time till here is enough even for media access */
104 	30000,	/* for true idiots */
105 	ULONG_MAX,
106 };
107 
108 static const unsigned long ata_eh_other_timeouts[] = {
109 	 5000,	/* same rationale as identify timeout */
110 	10000,	/* ditto */
111 	/* but no merciful 30sec for other commands, it just isn't worth it */
112 	ULONG_MAX,
113 };
114 
115 struct ata_eh_cmd_timeout_ent {
116 	const u8		*commands;
117 	const unsigned long	*timeouts;
118 };
119 
120 /* The following table determines timeouts to use for EH internal
121  * commands.  Each table entry is a command class and matches the
122  * commands the entry applies to and the timeout table to use.
123  *
124  * On the retry after a command timed out, the next timeout value from
125  * the table is used.  If the table doesn't contain further entries,
126  * the last value is used.
127  *
128  * ehc->cmd_timeout_idx keeps track of which timeout to use per
129  * command class, so if SET_FEATURES times out on the first try, the
130  * next try will use the second timeout value only for that class.
131  */
132 #define CMDS(cmds...)	(const u8 []){ cmds, 0 }
133 static const struct ata_eh_cmd_timeout_ent
134 ata_eh_cmd_timeout_table[ATA_EH_CMD_TIMEOUT_TABLE_SIZE] = {
135 	{ .commands = CMDS(ATA_CMD_ID_ATA, ATA_CMD_ID_ATAPI),
136 	  .timeouts = ata_eh_identify_timeouts, },
137 	{ .commands = CMDS(ATA_CMD_READ_NATIVE_MAX, ATA_CMD_READ_NATIVE_MAX_EXT),
138 	  .timeouts = ata_eh_other_timeouts, },
139 	{ .commands = CMDS(ATA_CMD_SET_MAX, ATA_CMD_SET_MAX_EXT),
140 	  .timeouts = ata_eh_other_timeouts, },
141 	{ .commands = CMDS(ATA_CMD_SET_FEATURES),
142 	  .timeouts = ata_eh_other_timeouts, },
143 	{ .commands = CMDS(ATA_CMD_INIT_DEV_PARAMS),
144 	  .timeouts = ata_eh_other_timeouts, },
145 };
146 #undef CMDS
147 
148 static void __ata_port_freeze(struct ata_port *ap);
149 #ifdef CONFIG_PM
150 static void ata_eh_handle_port_suspend(struct ata_port *ap);
151 static void ata_eh_handle_port_resume(struct ata_port *ap);
152 #else /* CONFIG_PM */
153 static void ata_eh_handle_port_suspend(struct ata_port *ap)
154 { }
155 
156 static void ata_eh_handle_port_resume(struct ata_port *ap)
157 { }
158 #endif /* CONFIG_PM */
159 
160 static void __ata_ehi_pushv_desc(struct ata_eh_info *ehi, const char *fmt,
161 				 va_list args)
162 {
163 	ehi->desc_len += vscnprintf(ehi->desc + ehi->desc_len,
164 				     ATA_EH_DESC_LEN - ehi->desc_len,
165 				     fmt, args);
166 }
167 
168 /**
169  *	__ata_ehi_push_desc - push error description without adding separator
170  *	@ehi: target EHI
171  *	@fmt: printf format string
172  *
173  *	Format string according to @fmt and append it to @ehi->desc.
174  *
175  *	LOCKING:
176  *	spin_lock_irqsave(host lock)
177  */
178 void __ata_ehi_push_desc(struct ata_eh_info *ehi, const char *fmt, ...)
179 {
180 	va_list args;
181 
182 	va_start(args, fmt);
183 	__ata_ehi_pushv_desc(ehi, fmt, args);
184 	va_end(args);
185 }
186 
187 /**
188  *	ata_ehi_push_desc - push error description with separator
189  *	@ehi: target EHI
190  *	@fmt: printf format string
191  *
192  *	Format string according to @fmt and append it to @ehi->desc.
193  *	If @ehi->desc is not empty, ", " is added in-between.
194  *
195  *	LOCKING:
196  *	spin_lock_irqsave(host lock)
197  */
198 void ata_ehi_push_desc(struct ata_eh_info *ehi, const char *fmt, ...)
199 {
200 	va_list args;
201 
202 	if (ehi->desc_len)
203 		__ata_ehi_push_desc(ehi, ", ");
204 
205 	va_start(args, fmt);
206 	__ata_ehi_pushv_desc(ehi, fmt, args);
207 	va_end(args);
208 }
209 
210 /**
211  *	ata_ehi_clear_desc - clean error description
212  *	@ehi: target EHI
213  *
214  *	Clear @ehi->desc.
215  *
216  *	LOCKING:
217  *	spin_lock_irqsave(host lock)
218  */
219 void ata_ehi_clear_desc(struct ata_eh_info *ehi)
220 {
221 	ehi->desc[0] = '\0';
222 	ehi->desc_len = 0;
223 }
224 
225 /**
226  *	ata_port_desc - append port description
227  *	@ap: target ATA port
228  *	@fmt: printf format string
229  *
230  *	Format string according to @fmt and append it to port
231  *	description.  If port description is not empty, " " is added
232  *	in-between.  This function is to be used while initializing
233  *	ata_host.  The description is printed on host registration.
234  *
235  *	LOCKING:
236  *	None.
237  */
238 void ata_port_desc(struct ata_port *ap, const char *fmt, ...)
239 {
240 	va_list args;
241 
242 	WARN_ON(!(ap->pflags & ATA_PFLAG_INITIALIZING));
243 
244 	if (ap->link.eh_info.desc_len)
245 		__ata_ehi_push_desc(&ap->link.eh_info, " ");
246 
247 	va_start(args, fmt);
248 	__ata_ehi_pushv_desc(&ap->link.eh_info, fmt, args);
249 	va_end(args);
250 }
251 
252 #ifdef CONFIG_PCI
253 
254 /**
255  *	ata_port_pbar_desc - append PCI BAR description
256  *	@ap: target ATA port
257  *	@bar: target PCI BAR
258  *	@offset: offset into PCI BAR
259  *	@name: name of the area
260  *
261  *	If @offset is negative, this function formats a string which
262  *	contains the name, address, size and type of the BAR and
263  *	appends it to the port description.  If @offset is zero or
264  *	positive, only name and offsetted address is appended.
265  *
266  *	LOCKING:
267  *	None.
268  */
269 void ata_port_pbar_desc(struct ata_port *ap, int bar, ssize_t offset,
270 			const char *name)
271 {
272 	struct pci_dev *pdev = to_pci_dev(ap->host->dev);
273 	char *type = "";
274 	unsigned long long start, len;
275 
276 	if (pci_resource_flags(pdev, bar) & IORESOURCE_MEM)
277 		type = "m";
278 	else if (pci_resource_flags(pdev, bar) & IORESOURCE_IO)
279 		type = "i";
280 
281 	start = (unsigned long long)pci_resource_start(pdev, bar);
282 	len = (unsigned long long)pci_resource_len(pdev, bar);
283 
284 	if (offset < 0)
285 		ata_port_desc(ap, "%s %s%llu@0x%llx", name, type, len, start);
286 	else
287 		ata_port_desc(ap, "%s 0x%llx", name,
288 				start + (unsigned long long)offset);
289 }
290 
291 #endif /* CONFIG_PCI */
292 
293 static int ata_lookup_timeout_table(u8 cmd)
294 {
295 	int i;
296 
297 	for (i = 0; i < ATA_EH_CMD_TIMEOUT_TABLE_SIZE; i++) {
298 		const u8 *cur;
299 
300 		for (cur = ata_eh_cmd_timeout_table[i].commands; *cur; cur++)
301 			if (*cur == cmd)
302 				return i;
303 	}
304 
305 	return -1;
306 }
307 
308 /**
309  *	ata_internal_cmd_timeout - determine timeout for an internal command
310  *	@dev: target device
311  *	@cmd: internal command to be issued
312  *
313  *	Determine timeout for internal command @cmd for @dev.
314  *
315  *	LOCKING:
316  *	EH context.
317  *
318  *	RETURNS:
319  *	Determined timeout.
320  */
321 unsigned long ata_internal_cmd_timeout(struct ata_device *dev, u8 cmd)
322 {
323 	struct ata_eh_context *ehc = &dev->link->eh_context;
324 	int ent = ata_lookup_timeout_table(cmd);
325 	int idx;
326 
327 	if (ent < 0)
328 		return ATA_EH_CMD_DFL_TIMEOUT;
329 
330 	idx = ehc->cmd_timeout_idx[dev->devno][ent];
331 	return ata_eh_cmd_timeout_table[ent].timeouts[idx];
332 }
333 
334 /**
335  *	ata_internal_cmd_timed_out - notification for internal command timeout
336  *	@dev: target device
337  *	@cmd: internal command which timed out
338  *
339  *	Notify EH that internal command @cmd for @dev timed out.  This
340  *	function should be called only for commands whose timeouts are
341  *	determined using ata_internal_cmd_timeout().
342  *
343  *	LOCKING:
344  *	EH context.
345  */
346 void ata_internal_cmd_timed_out(struct ata_device *dev, u8 cmd)
347 {
348 	struct ata_eh_context *ehc = &dev->link->eh_context;
349 	int ent = ata_lookup_timeout_table(cmd);
350 	int idx;
351 
352 	if (ent < 0)
353 		return;
354 
355 	idx = ehc->cmd_timeout_idx[dev->devno][ent];
356 	if (ata_eh_cmd_timeout_table[ent].timeouts[idx + 1] != ULONG_MAX)
357 		ehc->cmd_timeout_idx[dev->devno][ent]++;
358 }
359 
360 static void ata_ering_record(struct ata_ering *ering, unsigned int eflags,
361 			     unsigned int err_mask)
362 {
363 	struct ata_ering_entry *ent;
364 
365 	WARN_ON(!err_mask);
366 
367 	ering->cursor++;
368 	ering->cursor %= ATA_ERING_SIZE;
369 
370 	ent = &ering->ring[ering->cursor];
371 	ent->eflags = eflags;
372 	ent->err_mask = err_mask;
373 	ent->timestamp = get_jiffies_64();
374 }
375 
376 static struct ata_ering_entry *ata_ering_top(struct ata_ering *ering)
377 {
378 	struct ata_ering_entry *ent = &ering->ring[ering->cursor];
379 
380 	if (ent->err_mask)
381 		return ent;
382 	return NULL;
383 }
384 
385 static void ata_ering_clear(struct ata_ering *ering)
386 {
387 	memset(ering, 0, sizeof(*ering));
388 }
389 
390 static int ata_ering_map(struct ata_ering *ering,
391 			 int (*map_fn)(struct ata_ering_entry *, void *),
392 			 void *arg)
393 {
394 	int idx, rc = 0;
395 	struct ata_ering_entry *ent;
396 
397 	idx = ering->cursor;
398 	do {
399 		ent = &ering->ring[idx];
400 		if (!ent->err_mask)
401 			break;
402 		rc = map_fn(ent, arg);
403 		if (rc)
404 			break;
405 		idx = (idx - 1 + ATA_ERING_SIZE) % ATA_ERING_SIZE;
406 	} while (idx != ering->cursor);
407 
408 	return rc;
409 }
410 
411 static unsigned int ata_eh_dev_action(struct ata_device *dev)
412 {
413 	struct ata_eh_context *ehc = &dev->link->eh_context;
414 
415 	return ehc->i.action | ehc->i.dev_action[dev->devno];
416 }
417 
418 static void ata_eh_clear_action(struct ata_link *link, struct ata_device *dev,
419 				struct ata_eh_info *ehi, unsigned int action)
420 {
421 	struct ata_device *tdev;
422 
423 	if (!dev) {
424 		ehi->action &= ~action;
425 		ata_link_for_each_dev(tdev, link)
426 			ehi->dev_action[tdev->devno] &= ~action;
427 	} else {
428 		/* doesn't make sense for port-wide EH actions */
429 		WARN_ON(!(action & ATA_EH_PERDEV_MASK));
430 
431 		/* break ehi->action into ehi->dev_action */
432 		if (ehi->action & action) {
433 			ata_link_for_each_dev(tdev, link)
434 				ehi->dev_action[tdev->devno] |=
435 					ehi->action & action;
436 			ehi->action &= ~action;
437 		}
438 
439 		/* turn off the specified per-dev action */
440 		ehi->dev_action[dev->devno] &= ~action;
441 	}
442 }
443 
444 /**
445  *	ata_scsi_timed_out - SCSI layer time out callback
446  *	@cmd: timed out SCSI command
447  *
448  *	Handles SCSI layer timeout.  We race with normal completion of
449  *	the qc for @cmd.  If the qc is already gone, we lose and let
450  *	the scsi command finish (EH_HANDLED).  Otherwise, the qc has
451  *	timed out and EH should be invoked.  Prevent ata_qc_complete()
452  *	from finishing it by setting EH_SCHEDULED and return
453  *	EH_NOT_HANDLED.
454  *
455  *	TODO: kill this function once old EH is gone.
456  *
457  *	LOCKING:
458  *	Called from timer context
459  *
460  *	RETURNS:
461  *	EH_HANDLED or EH_NOT_HANDLED
462  */
463 enum blk_eh_timer_return ata_scsi_timed_out(struct scsi_cmnd *cmd)
464 {
465 	struct Scsi_Host *host = cmd->device->host;
466 	struct ata_port *ap = ata_shost_to_port(host);
467 	unsigned long flags;
468 	struct ata_queued_cmd *qc;
469 	enum blk_eh_timer_return ret;
470 
471 	DPRINTK("ENTER\n");
472 
473 	if (ap->ops->error_handler) {
474 		ret = BLK_EH_NOT_HANDLED;
475 		goto out;
476 	}
477 
478 	ret = BLK_EH_HANDLED;
479 	spin_lock_irqsave(ap->lock, flags);
480 	qc = ata_qc_from_tag(ap, ap->link.active_tag);
481 	if (qc) {
482 		WARN_ON(qc->scsicmd != cmd);
483 		qc->flags |= ATA_QCFLAG_EH_SCHEDULED;
484 		qc->err_mask |= AC_ERR_TIMEOUT;
485 		ret = BLK_EH_NOT_HANDLED;
486 	}
487 	spin_unlock_irqrestore(ap->lock, flags);
488 
489  out:
490 	DPRINTK("EXIT, ret=%d\n", ret);
491 	return ret;
492 }
493 
494 /**
495  *	ata_scsi_error - SCSI layer error handler callback
496  *	@host: SCSI host on which error occurred
497  *
498  *	Handles SCSI-layer-thrown error events.
499  *
500  *	LOCKING:
501  *	Inherited from SCSI layer (none, can sleep)
502  *
503  *	RETURNS:
504  *	Zero.
505  */
506 void ata_scsi_error(struct Scsi_Host *host)
507 {
508 	struct ata_port *ap = ata_shost_to_port(host);
509 	int i;
510 	unsigned long flags;
511 
512 	DPRINTK("ENTER\n");
513 
514 	/* synchronize with port task */
515 	ata_port_flush_task(ap);
516 
517 	/* synchronize with host lock and sort out timeouts */
518 
519 	/* For new EH, all qcs are finished in one of three ways -
520 	 * normal completion, error completion, and SCSI timeout.
521 	 * Both cmpletions can race against SCSI timeout.  When normal
522 	 * completion wins, the qc never reaches EH.  When error
523 	 * completion wins, the qc has ATA_QCFLAG_FAILED set.
524 	 *
525 	 * When SCSI timeout wins, things are a bit more complex.
526 	 * Normal or error completion can occur after the timeout but
527 	 * before this point.  In such cases, both types of
528 	 * completions are honored.  A scmd is determined to have
529 	 * timed out iff its associated qc is active and not failed.
530 	 */
531 	if (ap->ops->error_handler) {
532 		struct scsi_cmnd *scmd, *tmp;
533 		int nr_timedout = 0;
534 
535 		spin_lock_irqsave(ap->lock, flags);
536 
537 		list_for_each_entry_safe(scmd, tmp, &host->eh_cmd_q, eh_entry) {
538 			struct ata_queued_cmd *qc;
539 
540 			for (i = 0; i < ATA_MAX_QUEUE; i++) {
541 				qc = __ata_qc_from_tag(ap, i);
542 				if (qc->flags & ATA_QCFLAG_ACTIVE &&
543 				    qc->scsicmd == scmd)
544 					break;
545 			}
546 
547 			if (i < ATA_MAX_QUEUE) {
548 				/* the scmd has an associated qc */
549 				if (!(qc->flags & ATA_QCFLAG_FAILED)) {
550 					/* which hasn't failed yet, timeout */
551 					qc->err_mask |= AC_ERR_TIMEOUT;
552 					qc->flags |= ATA_QCFLAG_FAILED;
553 					nr_timedout++;
554 				}
555 			} else {
556 				/* Normal completion occurred after
557 				 * SCSI timeout but before this point.
558 				 * Successfully complete it.
559 				 */
560 				scmd->retries = scmd->allowed;
561 				scsi_eh_finish_cmd(scmd, &ap->eh_done_q);
562 			}
563 		}
564 
565 		/* If we have timed out qcs.  They belong to EH from
566 		 * this point but the state of the controller is
567 		 * unknown.  Freeze the port to make sure the IRQ
568 		 * handler doesn't diddle with those qcs.  This must
569 		 * be done atomically w.r.t. setting QCFLAG_FAILED.
570 		 */
571 		if (nr_timedout)
572 			__ata_port_freeze(ap);
573 
574 		spin_unlock_irqrestore(ap->lock, flags);
575 
576 		/* initialize eh_tries */
577 		ap->eh_tries = ATA_EH_MAX_TRIES;
578 	} else
579 		spin_unlock_wait(ap->lock);
580 
581  repeat:
582 	/* invoke error handler */
583 	if (ap->ops->error_handler) {
584 		struct ata_link *link;
585 
586 		/* kill fast drain timer */
587 		del_timer_sync(&ap->fastdrain_timer);
588 
589 		/* process port resume request */
590 		ata_eh_handle_port_resume(ap);
591 
592 		/* fetch & clear EH info */
593 		spin_lock_irqsave(ap->lock, flags);
594 
595 		__ata_port_for_each_link(link, ap) {
596 			struct ata_eh_context *ehc = &link->eh_context;
597 			struct ata_device *dev;
598 
599 			memset(&link->eh_context, 0, sizeof(link->eh_context));
600 			link->eh_context.i = link->eh_info;
601 			memset(&link->eh_info, 0, sizeof(link->eh_info));
602 
603 			ata_link_for_each_dev(dev, link) {
604 				int devno = dev->devno;
605 
606 				if (!ata_dev_enabled(dev))
607 					continue;
608 
609 				ehc->saved_xfer_mode[devno] = dev->xfer_mode;
610 				if (ata_ncq_enabled(dev))
611 					ehc->saved_ncq_enabled |= 1 << devno;
612 			}
613 		}
614 
615 		ap->pflags |= ATA_PFLAG_EH_IN_PROGRESS;
616 		ap->pflags &= ~ATA_PFLAG_EH_PENDING;
617 		ap->excl_link = NULL;	/* don't maintain exclusion over EH */
618 
619 		spin_unlock_irqrestore(ap->lock, flags);
620 
621 		/* invoke EH, skip if unloading or suspended */
622 		if (!(ap->pflags & (ATA_PFLAG_UNLOADING | ATA_PFLAG_SUSPENDED)))
623 			ap->ops->error_handler(ap);
624 		else
625 			ata_eh_finish(ap);
626 
627 		/* process port suspend request */
628 		ata_eh_handle_port_suspend(ap);
629 
630 		/* Exception might have happend after ->error_handler
631 		 * recovered the port but before this point.  Repeat
632 		 * EH in such case.
633 		 */
634 		spin_lock_irqsave(ap->lock, flags);
635 
636 		if (ap->pflags & ATA_PFLAG_EH_PENDING) {
637 			if (--ap->eh_tries) {
638 				spin_unlock_irqrestore(ap->lock, flags);
639 				goto repeat;
640 			}
641 			ata_port_printk(ap, KERN_ERR, "EH pending after %d "
642 					"tries, giving up\n", ATA_EH_MAX_TRIES);
643 			ap->pflags &= ~ATA_PFLAG_EH_PENDING;
644 		}
645 
646 		/* this run is complete, make sure EH info is clear */
647 		__ata_port_for_each_link(link, ap)
648 			memset(&link->eh_info, 0, sizeof(link->eh_info));
649 
650 		/* Clear host_eh_scheduled while holding ap->lock such
651 		 * that if exception occurs after this point but
652 		 * before EH completion, SCSI midlayer will
653 		 * re-initiate EH.
654 		 */
655 		host->host_eh_scheduled = 0;
656 
657 		spin_unlock_irqrestore(ap->lock, flags);
658 	} else {
659 		WARN_ON(ata_qc_from_tag(ap, ap->link.active_tag) == NULL);
660 		ap->ops->eng_timeout(ap);
661 	}
662 
663 	/* finish or retry handled scmd's and clean up */
664 	WARN_ON(host->host_failed || !list_empty(&host->eh_cmd_q));
665 
666 	scsi_eh_flush_done_q(&ap->eh_done_q);
667 
668 	/* clean up */
669 	spin_lock_irqsave(ap->lock, flags);
670 
671 	if (ap->pflags & ATA_PFLAG_LOADING)
672 		ap->pflags &= ~ATA_PFLAG_LOADING;
673 	else if (ap->pflags & ATA_PFLAG_SCSI_HOTPLUG)
674 		queue_delayed_work(ata_aux_wq, &ap->hotplug_task, 0);
675 
676 	if (ap->pflags & ATA_PFLAG_RECOVERED)
677 		ata_port_printk(ap, KERN_INFO, "EH complete\n");
678 
679 	ap->pflags &= ~(ATA_PFLAG_SCSI_HOTPLUG | ATA_PFLAG_RECOVERED);
680 
681 	/* tell wait_eh that we're done */
682 	ap->pflags &= ~ATA_PFLAG_EH_IN_PROGRESS;
683 	wake_up_all(&ap->eh_wait_q);
684 
685 	spin_unlock_irqrestore(ap->lock, flags);
686 
687 	DPRINTK("EXIT\n");
688 }
689 
690 /**
691  *	ata_port_wait_eh - Wait for the currently pending EH to complete
692  *	@ap: Port to wait EH for
693  *
694  *	Wait until the currently pending EH is complete.
695  *
696  *	LOCKING:
697  *	Kernel thread context (may sleep).
698  */
699 void ata_port_wait_eh(struct ata_port *ap)
700 {
701 	unsigned long flags;
702 	DEFINE_WAIT(wait);
703 
704  retry:
705 	spin_lock_irqsave(ap->lock, flags);
706 
707 	while (ap->pflags & (ATA_PFLAG_EH_PENDING | ATA_PFLAG_EH_IN_PROGRESS)) {
708 		prepare_to_wait(&ap->eh_wait_q, &wait, TASK_UNINTERRUPTIBLE);
709 		spin_unlock_irqrestore(ap->lock, flags);
710 		schedule();
711 		spin_lock_irqsave(ap->lock, flags);
712 	}
713 	finish_wait(&ap->eh_wait_q, &wait);
714 
715 	spin_unlock_irqrestore(ap->lock, flags);
716 
717 	/* make sure SCSI EH is complete */
718 	if (scsi_host_in_recovery(ap->scsi_host)) {
719 		msleep(10);
720 		goto retry;
721 	}
722 }
723 
724 static int ata_eh_nr_in_flight(struct ata_port *ap)
725 {
726 	unsigned int tag;
727 	int nr = 0;
728 
729 	/* count only non-internal commands */
730 	for (tag = 0; tag < ATA_MAX_QUEUE - 1; tag++)
731 		if (ata_qc_from_tag(ap, tag))
732 			nr++;
733 
734 	return nr;
735 }
736 
737 void ata_eh_fastdrain_timerfn(unsigned long arg)
738 {
739 	struct ata_port *ap = (void *)arg;
740 	unsigned long flags;
741 	int cnt;
742 
743 	spin_lock_irqsave(ap->lock, flags);
744 
745 	cnt = ata_eh_nr_in_flight(ap);
746 
747 	/* are we done? */
748 	if (!cnt)
749 		goto out_unlock;
750 
751 	if (cnt == ap->fastdrain_cnt) {
752 		unsigned int tag;
753 
754 		/* No progress during the last interval, tag all
755 		 * in-flight qcs as timed out and freeze the port.
756 		 */
757 		for (tag = 0; tag < ATA_MAX_QUEUE - 1; tag++) {
758 			struct ata_queued_cmd *qc = ata_qc_from_tag(ap, tag);
759 			if (qc)
760 				qc->err_mask |= AC_ERR_TIMEOUT;
761 		}
762 
763 		ata_port_freeze(ap);
764 	} else {
765 		/* some qcs have finished, give it another chance */
766 		ap->fastdrain_cnt = cnt;
767 		ap->fastdrain_timer.expires =
768 			ata_deadline(jiffies, ATA_EH_FASTDRAIN_INTERVAL);
769 		add_timer(&ap->fastdrain_timer);
770 	}
771 
772  out_unlock:
773 	spin_unlock_irqrestore(ap->lock, flags);
774 }
775 
776 /**
777  *	ata_eh_set_pending - set ATA_PFLAG_EH_PENDING and activate fast drain
778  *	@ap: target ATA port
779  *	@fastdrain: activate fast drain
780  *
781  *	Set ATA_PFLAG_EH_PENDING and activate fast drain if @fastdrain
782  *	is non-zero and EH wasn't pending before.  Fast drain ensures
783  *	that EH kicks in in timely manner.
784  *
785  *	LOCKING:
786  *	spin_lock_irqsave(host lock)
787  */
788 static void ata_eh_set_pending(struct ata_port *ap, int fastdrain)
789 {
790 	int cnt;
791 
792 	/* already scheduled? */
793 	if (ap->pflags & ATA_PFLAG_EH_PENDING)
794 		return;
795 
796 	ap->pflags |= ATA_PFLAG_EH_PENDING;
797 
798 	if (!fastdrain)
799 		return;
800 
801 	/* do we have in-flight qcs? */
802 	cnt = ata_eh_nr_in_flight(ap);
803 	if (!cnt)
804 		return;
805 
806 	/* activate fast drain */
807 	ap->fastdrain_cnt = cnt;
808 	ap->fastdrain_timer.expires =
809 		ata_deadline(jiffies, ATA_EH_FASTDRAIN_INTERVAL);
810 	add_timer(&ap->fastdrain_timer);
811 }
812 
813 /**
814  *	ata_qc_schedule_eh - schedule qc for error handling
815  *	@qc: command to schedule error handling for
816  *
817  *	Schedule error handling for @qc.  EH will kick in as soon as
818  *	other commands are drained.
819  *
820  *	LOCKING:
821  *	spin_lock_irqsave(host lock)
822  */
823 void ata_qc_schedule_eh(struct ata_queued_cmd *qc)
824 {
825 	struct ata_port *ap = qc->ap;
826 
827 	WARN_ON(!ap->ops->error_handler);
828 
829 	qc->flags |= ATA_QCFLAG_FAILED;
830 	ata_eh_set_pending(ap, 1);
831 
832 	/* The following will fail if timeout has already expired.
833 	 * ata_scsi_error() takes care of such scmds on EH entry.
834 	 * Note that ATA_QCFLAG_FAILED is unconditionally set after
835 	 * this function completes.
836 	 */
837 	blk_abort_request(qc->scsicmd->request);
838 }
839 
840 /**
841  *	ata_port_schedule_eh - schedule error handling without a qc
842  *	@ap: ATA port to schedule EH for
843  *
844  *	Schedule error handling for @ap.  EH will kick in as soon as
845  *	all commands are drained.
846  *
847  *	LOCKING:
848  *	spin_lock_irqsave(host lock)
849  */
850 void ata_port_schedule_eh(struct ata_port *ap)
851 {
852 	WARN_ON(!ap->ops->error_handler);
853 
854 	if (ap->pflags & ATA_PFLAG_INITIALIZING)
855 		return;
856 
857 	ata_eh_set_pending(ap, 1);
858 	scsi_schedule_eh(ap->scsi_host);
859 
860 	DPRINTK("port EH scheduled\n");
861 }
862 
863 static int ata_do_link_abort(struct ata_port *ap, struct ata_link *link)
864 {
865 	int tag, nr_aborted = 0;
866 
867 	WARN_ON(!ap->ops->error_handler);
868 
869 	/* we're gonna abort all commands, no need for fast drain */
870 	ata_eh_set_pending(ap, 0);
871 
872 	for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
873 		struct ata_queued_cmd *qc = ata_qc_from_tag(ap, tag);
874 
875 		if (qc && (!link || qc->dev->link == link)) {
876 			qc->flags |= ATA_QCFLAG_FAILED;
877 			ata_qc_complete(qc);
878 			nr_aborted++;
879 		}
880 	}
881 
882 	if (!nr_aborted)
883 		ata_port_schedule_eh(ap);
884 
885 	return nr_aborted;
886 }
887 
888 /**
889  *	ata_link_abort - abort all qc's on the link
890  *	@link: ATA link to abort qc's for
891  *
892  *	Abort all active qc's active on @link and schedule EH.
893  *
894  *	LOCKING:
895  *	spin_lock_irqsave(host lock)
896  *
897  *	RETURNS:
898  *	Number of aborted qc's.
899  */
900 int ata_link_abort(struct ata_link *link)
901 {
902 	return ata_do_link_abort(link->ap, link);
903 }
904 
905 /**
906  *	ata_port_abort - abort all qc's on the port
907  *	@ap: ATA port to abort qc's for
908  *
909  *	Abort all active qc's of @ap and schedule EH.
910  *
911  *	LOCKING:
912  *	spin_lock_irqsave(host_set lock)
913  *
914  *	RETURNS:
915  *	Number of aborted qc's.
916  */
917 int ata_port_abort(struct ata_port *ap)
918 {
919 	return ata_do_link_abort(ap, NULL);
920 }
921 
922 /**
923  *	__ata_port_freeze - freeze port
924  *	@ap: ATA port to freeze
925  *
926  *	This function is called when HSM violation or some other
927  *	condition disrupts normal operation of the port.  Frozen port
928  *	is not allowed to perform any operation until the port is
929  *	thawed, which usually follows a successful reset.
930  *
931  *	ap->ops->freeze() callback can be used for freezing the port
932  *	hardware-wise (e.g. mask interrupt and stop DMA engine).  If a
933  *	port cannot be frozen hardware-wise, the interrupt handler
934  *	must ack and clear interrupts unconditionally while the port
935  *	is frozen.
936  *
937  *	LOCKING:
938  *	spin_lock_irqsave(host lock)
939  */
940 static void __ata_port_freeze(struct ata_port *ap)
941 {
942 	WARN_ON(!ap->ops->error_handler);
943 
944 	if (ap->ops->freeze)
945 		ap->ops->freeze(ap);
946 
947 	ap->pflags |= ATA_PFLAG_FROZEN;
948 
949 	DPRINTK("ata%u port frozen\n", ap->print_id);
950 }
951 
952 /**
953  *	ata_port_freeze - abort & freeze port
954  *	@ap: ATA port to freeze
955  *
956  *	Abort and freeze @ap.
957  *
958  *	LOCKING:
959  *	spin_lock_irqsave(host lock)
960  *
961  *	RETURNS:
962  *	Number of aborted commands.
963  */
964 int ata_port_freeze(struct ata_port *ap)
965 {
966 	int nr_aborted;
967 
968 	WARN_ON(!ap->ops->error_handler);
969 
970 	nr_aborted = ata_port_abort(ap);
971 	__ata_port_freeze(ap);
972 
973 	return nr_aborted;
974 }
975 
976 /**
977  *	sata_async_notification - SATA async notification handler
978  *	@ap: ATA port where async notification is received
979  *
980  *	Handler to be called when async notification via SDB FIS is
981  *	received.  This function schedules EH if necessary.
982  *
983  *	LOCKING:
984  *	spin_lock_irqsave(host lock)
985  *
986  *	RETURNS:
987  *	1 if EH is scheduled, 0 otherwise.
988  */
989 int sata_async_notification(struct ata_port *ap)
990 {
991 	u32 sntf;
992 	int rc;
993 
994 	if (!(ap->flags & ATA_FLAG_AN))
995 		return 0;
996 
997 	rc = sata_scr_read(&ap->link, SCR_NOTIFICATION, &sntf);
998 	if (rc == 0)
999 		sata_scr_write(&ap->link, SCR_NOTIFICATION, sntf);
1000 
1001 	if (!sata_pmp_attached(ap) || rc) {
1002 		/* PMP is not attached or SNTF is not available */
1003 		if (!sata_pmp_attached(ap)) {
1004 			/* PMP is not attached.  Check whether ATAPI
1005 			 * AN is configured.  If so, notify media
1006 			 * change.
1007 			 */
1008 			struct ata_device *dev = ap->link.device;
1009 
1010 			if ((dev->class == ATA_DEV_ATAPI) &&
1011 			    (dev->flags & ATA_DFLAG_AN))
1012 				ata_scsi_media_change_notify(dev);
1013 			return 0;
1014 		} else {
1015 			/* PMP is attached but SNTF is not available.
1016 			 * ATAPI async media change notification is
1017 			 * not used.  The PMP must be reporting PHY
1018 			 * status change, schedule EH.
1019 			 */
1020 			ata_port_schedule_eh(ap);
1021 			return 1;
1022 		}
1023 	} else {
1024 		/* PMP is attached and SNTF is available */
1025 		struct ata_link *link;
1026 
1027 		/* check and notify ATAPI AN */
1028 		ata_port_for_each_link(link, ap) {
1029 			if (!(sntf & (1 << link->pmp)))
1030 				continue;
1031 
1032 			if ((link->device->class == ATA_DEV_ATAPI) &&
1033 			    (link->device->flags & ATA_DFLAG_AN))
1034 				ata_scsi_media_change_notify(link->device);
1035 		}
1036 
1037 		/* If PMP is reporting that PHY status of some
1038 		 * downstream ports has changed, schedule EH.
1039 		 */
1040 		if (sntf & (1 << SATA_PMP_CTRL_PORT)) {
1041 			ata_port_schedule_eh(ap);
1042 			return 1;
1043 		}
1044 
1045 		return 0;
1046 	}
1047 }
1048 
1049 /**
1050  *	ata_eh_freeze_port - EH helper to freeze port
1051  *	@ap: ATA port to freeze
1052  *
1053  *	Freeze @ap.
1054  *
1055  *	LOCKING:
1056  *	None.
1057  */
1058 void ata_eh_freeze_port(struct ata_port *ap)
1059 {
1060 	unsigned long flags;
1061 
1062 	if (!ap->ops->error_handler)
1063 		return;
1064 
1065 	spin_lock_irqsave(ap->lock, flags);
1066 	__ata_port_freeze(ap);
1067 	spin_unlock_irqrestore(ap->lock, flags);
1068 }
1069 
1070 /**
1071  *	ata_port_thaw_port - EH helper to thaw port
1072  *	@ap: ATA port to thaw
1073  *
1074  *	Thaw frozen port @ap.
1075  *
1076  *	LOCKING:
1077  *	None.
1078  */
1079 void ata_eh_thaw_port(struct ata_port *ap)
1080 {
1081 	unsigned long flags;
1082 
1083 	if (!ap->ops->error_handler)
1084 		return;
1085 
1086 	spin_lock_irqsave(ap->lock, flags);
1087 
1088 	ap->pflags &= ~ATA_PFLAG_FROZEN;
1089 
1090 	if (ap->ops->thaw)
1091 		ap->ops->thaw(ap);
1092 
1093 	spin_unlock_irqrestore(ap->lock, flags);
1094 
1095 	DPRINTK("ata%u port thawed\n", ap->print_id);
1096 }
1097 
1098 static void ata_eh_scsidone(struct scsi_cmnd *scmd)
1099 {
1100 	/* nada */
1101 }
1102 
1103 static void __ata_eh_qc_complete(struct ata_queued_cmd *qc)
1104 {
1105 	struct ata_port *ap = qc->ap;
1106 	struct scsi_cmnd *scmd = qc->scsicmd;
1107 	unsigned long flags;
1108 
1109 	spin_lock_irqsave(ap->lock, flags);
1110 	qc->scsidone = ata_eh_scsidone;
1111 	__ata_qc_complete(qc);
1112 	WARN_ON(ata_tag_valid(qc->tag));
1113 	spin_unlock_irqrestore(ap->lock, flags);
1114 
1115 	scsi_eh_finish_cmd(scmd, &ap->eh_done_q);
1116 }
1117 
1118 /**
1119  *	ata_eh_qc_complete - Complete an active ATA command from EH
1120  *	@qc: Command to complete
1121  *
1122  *	Indicate to the mid and upper layers that an ATA command has
1123  *	completed.  To be used from EH.
1124  */
1125 void ata_eh_qc_complete(struct ata_queued_cmd *qc)
1126 {
1127 	struct scsi_cmnd *scmd = qc->scsicmd;
1128 	scmd->retries = scmd->allowed;
1129 	__ata_eh_qc_complete(qc);
1130 }
1131 
1132 /**
1133  *	ata_eh_qc_retry - Tell midlayer to retry an ATA command after EH
1134  *	@qc: Command to retry
1135  *
1136  *	Indicate to the mid and upper layers that an ATA command
1137  *	should be retried.  To be used from EH.
1138  *
1139  *	SCSI midlayer limits the number of retries to scmd->allowed.
1140  *	scmd->retries is decremented for commands which get retried
1141  *	due to unrelated failures (qc->err_mask is zero).
1142  */
1143 void ata_eh_qc_retry(struct ata_queued_cmd *qc)
1144 {
1145 	struct scsi_cmnd *scmd = qc->scsicmd;
1146 	if (!qc->err_mask && scmd->retries)
1147 		scmd->retries--;
1148 	__ata_eh_qc_complete(qc);
1149 }
1150 
1151 /**
1152  *	ata_eh_detach_dev - detach ATA device
1153  *	@dev: ATA device to detach
1154  *
1155  *	Detach @dev.
1156  *
1157  *	LOCKING:
1158  *	None.
1159  */
1160 void ata_eh_detach_dev(struct ata_device *dev)
1161 {
1162 	struct ata_link *link = dev->link;
1163 	struct ata_port *ap = link->ap;
1164 	struct ata_eh_context *ehc = &link->eh_context;
1165 	unsigned long flags;
1166 
1167 	ata_dev_disable(dev);
1168 
1169 	spin_lock_irqsave(ap->lock, flags);
1170 
1171 	dev->flags &= ~ATA_DFLAG_DETACH;
1172 
1173 	if (ata_scsi_offline_dev(dev)) {
1174 		dev->flags |= ATA_DFLAG_DETACHED;
1175 		ap->pflags |= ATA_PFLAG_SCSI_HOTPLUG;
1176 	}
1177 
1178 	/* clear per-dev EH info */
1179 	ata_eh_clear_action(link, dev, &link->eh_info, ATA_EH_PERDEV_MASK);
1180 	ata_eh_clear_action(link, dev, &link->eh_context.i, ATA_EH_PERDEV_MASK);
1181 	ehc->saved_xfer_mode[dev->devno] = 0;
1182 	ehc->saved_ncq_enabled &= ~(1 << dev->devno);
1183 
1184 	spin_unlock_irqrestore(ap->lock, flags);
1185 }
1186 
1187 /**
1188  *	ata_eh_about_to_do - about to perform eh_action
1189  *	@link: target ATA link
1190  *	@dev: target ATA dev for per-dev action (can be NULL)
1191  *	@action: action about to be performed
1192  *
1193  *	Called just before performing EH actions to clear related bits
1194  *	in @link->eh_info such that eh actions are not unnecessarily
1195  *	repeated.
1196  *
1197  *	LOCKING:
1198  *	None.
1199  */
1200 void ata_eh_about_to_do(struct ata_link *link, struct ata_device *dev,
1201 			unsigned int action)
1202 {
1203 	struct ata_port *ap = link->ap;
1204 	struct ata_eh_info *ehi = &link->eh_info;
1205 	struct ata_eh_context *ehc = &link->eh_context;
1206 	unsigned long flags;
1207 
1208 	spin_lock_irqsave(ap->lock, flags);
1209 
1210 	ata_eh_clear_action(link, dev, ehi, action);
1211 
1212 	/* About to take EH action, set RECOVERED.  Ignore actions on
1213 	 * slave links as master will do them again.
1214 	 */
1215 	if (!(ehc->i.flags & ATA_EHI_QUIET) && link != ap->slave_link)
1216 		ap->pflags |= ATA_PFLAG_RECOVERED;
1217 
1218 	spin_unlock_irqrestore(ap->lock, flags);
1219 }
1220 
1221 /**
1222  *	ata_eh_done - EH action complete
1223 *	@ap: target ATA port
1224  *	@dev: target ATA dev for per-dev action (can be NULL)
1225  *	@action: action just completed
1226  *
1227  *	Called right after performing EH actions to clear related bits
1228  *	in @link->eh_context.
1229  *
1230  *	LOCKING:
1231  *	None.
1232  */
1233 void ata_eh_done(struct ata_link *link, struct ata_device *dev,
1234 		 unsigned int action)
1235 {
1236 	struct ata_eh_context *ehc = &link->eh_context;
1237 
1238 	ata_eh_clear_action(link, dev, &ehc->i, action);
1239 }
1240 
1241 /**
1242  *	ata_err_string - convert err_mask to descriptive string
1243  *	@err_mask: error mask to convert to string
1244  *
1245  *	Convert @err_mask to descriptive string.  Errors are
1246  *	prioritized according to severity and only the most severe
1247  *	error is reported.
1248  *
1249  *	LOCKING:
1250  *	None.
1251  *
1252  *	RETURNS:
1253  *	Descriptive string for @err_mask
1254  */
1255 static const char *ata_err_string(unsigned int err_mask)
1256 {
1257 	if (err_mask & AC_ERR_HOST_BUS)
1258 		return "host bus error";
1259 	if (err_mask & AC_ERR_ATA_BUS)
1260 		return "ATA bus error";
1261 	if (err_mask & AC_ERR_TIMEOUT)
1262 		return "timeout";
1263 	if (err_mask & AC_ERR_HSM)
1264 		return "HSM violation";
1265 	if (err_mask & AC_ERR_SYSTEM)
1266 		return "internal error";
1267 	if (err_mask & AC_ERR_MEDIA)
1268 		return "media error";
1269 	if (err_mask & AC_ERR_INVALID)
1270 		return "invalid argument";
1271 	if (err_mask & AC_ERR_DEV)
1272 		return "device error";
1273 	return "unknown error";
1274 }
1275 
1276 /**
1277  *	ata_read_log_page - read a specific log page
1278  *	@dev: target device
1279  *	@page: page to read
1280  *	@buf: buffer to store read page
1281  *	@sectors: number of sectors to read
1282  *
1283  *	Read log page using READ_LOG_EXT command.
1284  *
1285  *	LOCKING:
1286  *	Kernel thread context (may sleep).
1287  *
1288  *	RETURNS:
1289  *	0 on success, AC_ERR_* mask otherwise.
1290  */
1291 static unsigned int ata_read_log_page(struct ata_device *dev,
1292 				      u8 page, void *buf, unsigned int sectors)
1293 {
1294 	struct ata_taskfile tf;
1295 	unsigned int err_mask;
1296 
1297 	DPRINTK("read log page - page %d\n", page);
1298 
1299 	ata_tf_init(dev, &tf);
1300 	tf.command = ATA_CMD_READ_LOG_EXT;
1301 	tf.lbal = page;
1302 	tf.nsect = sectors;
1303 	tf.hob_nsect = sectors >> 8;
1304 	tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_LBA48 | ATA_TFLAG_DEVICE;
1305 	tf.protocol = ATA_PROT_PIO;
1306 
1307 	err_mask = ata_exec_internal(dev, &tf, NULL, DMA_FROM_DEVICE,
1308 				     buf, sectors * ATA_SECT_SIZE, 0);
1309 
1310 	DPRINTK("EXIT, err_mask=%x\n", err_mask);
1311 	return err_mask;
1312 }
1313 
1314 /**
1315  *	ata_eh_read_log_10h - Read log page 10h for NCQ error details
1316  *	@dev: Device to read log page 10h from
1317  *	@tag: Resulting tag of the failed command
1318  *	@tf: Resulting taskfile registers of the failed command
1319  *
1320  *	Read log page 10h to obtain NCQ error details and clear error
1321  *	condition.
1322  *
1323  *	LOCKING:
1324  *	Kernel thread context (may sleep).
1325  *
1326  *	RETURNS:
1327  *	0 on success, -errno otherwise.
1328  */
1329 static int ata_eh_read_log_10h(struct ata_device *dev,
1330 			       int *tag, struct ata_taskfile *tf)
1331 {
1332 	u8 *buf = dev->link->ap->sector_buf;
1333 	unsigned int err_mask;
1334 	u8 csum;
1335 	int i;
1336 
1337 	err_mask = ata_read_log_page(dev, ATA_LOG_SATA_NCQ, buf, 1);
1338 	if (err_mask)
1339 		return -EIO;
1340 
1341 	csum = 0;
1342 	for (i = 0; i < ATA_SECT_SIZE; i++)
1343 		csum += buf[i];
1344 	if (csum)
1345 		ata_dev_printk(dev, KERN_WARNING,
1346 			       "invalid checksum 0x%x on log page 10h\n", csum);
1347 
1348 	if (buf[0] & 0x80)
1349 		return -ENOENT;
1350 
1351 	*tag = buf[0] & 0x1f;
1352 
1353 	tf->command = buf[2];
1354 	tf->feature = buf[3];
1355 	tf->lbal = buf[4];
1356 	tf->lbam = buf[5];
1357 	tf->lbah = buf[6];
1358 	tf->device = buf[7];
1359 	tf->hob_lbal = buf[8];
1360 	tf->hob_lbam = buf[9];
1361 	tf->hob_lbah = buf[10];
1362 	tf->nsect = buf[12];
1363 	tf->hob_nsect = buf[13];
1364 
1365 	return 0;
1366 }
1367 
1368 /**
1369  *	atapi_eh_tur - perform ATAPI TEST_UNIT_READY
1370  *	@dev: target ATAPI device
1371  *	@r_sense_key: out parameter for sense_key
1372  *
1373  *	Perform ATAPI TEST_UNIT_READY.
1374  *
1375  *	LOCKING:
1376  *	EH context (may sleep).
1377  *
1378  *	RETURNS:
1379  *	0 on success, AC_ERR_* mask on failure.
1380  */
1381 static unsigned int atapi_eh_tur(struct ata_device *dev, u8 *r_sense_key)
1382 {
1383 	u8 cdb[ATAPI_CDB_LEN] = { TEST_UNIT_READY, 0, 0, 0, 0, 0 };
1384 	struct ata_taskfile tf;
1385 	unsigned int err_mask;
1386 
1387 	ata_tf_init(dev, &tf);
1388 
1389 	tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
1390 	tf.command = ATA_CMD_PACKET;
1391 	tf.protocol = ATAPI_PROT_NODATA;
1392 
1393 	err_mask = ata_exec_internal(dev, &tf, cdb, DMA_NONE, NULL, 0, 0);
1394 	if (err_mask == AC_ERR_DEV)
1395 		*r_sense_key = tf.feature >> 4;
1396 	return err_mask;
1397 }
1398 
1399 /**
1400  *	atapi_eh_request_sense - perform ATAPI REQUEST_SENSE
1401  *	@dev: device to perform REQUEST_SENSE to
1402  *	@sense_buf: result sense data buffer (SCSI_SENSE_BUFFERSIZE bytes long)
1403  *	@dfl_sense_key: default sense key to use
1404  *
1405  *	Perform ATAPI REQUEST_SENSE after the device reported CHECK
1406  *	SENSE.  This function is EH helper.
1407  *
1408  *	LOCKING:
1409  *	Kernel thread context (may sleep).
1410  *
1411  *	RETURNS:
1412  *	0 on success, AC_ERR_* mask on failure
1413  */
1414 static unsigned int atapi_eh_request_sense(struct ata_device *dev,
1415 					   u8 *sense_buf, u8 dfl_sense_key)
1416 {
1417 	u8 cdb[ATAPI_CDB_LEN] =
1418 		{ REQUEST_SENSE, 0, 0, 0, SCSI_SENSE_BUFFERSIZE, 0 };
1419 	struct ata_port *ap = dev->link->ap;
1420 	struct ata_taskfile tf;
1421 
1422 	DPRINTK("ATAPI request sense\n");
1423 
1424 	/* FIXME: is this needed? */
1425 	memset(sense_buf, 0, SCSI_SENSE_BUFFERSIZE);
1426 
1427 	/* initialize sense_buf with the error register,
1428 	 * for the case where they are -not- overwritten
1429 	 */
1430 	sense_buf[0] = 0x70;
1431 	sense_buf[2] = dfl_sense_key;
1432 
1433 	/* some devices time out if garbage left in tf */
1434 	ata_tf_init(dev, &tf);
1435 
1436 	tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
1437 	tf.command = ATA_CMD_PACKET;
1438 
1439 	/* is it pointless to prefer PIO for "safety reasons"? */
1440 	if (ap->flags & ATA_FLAG_PIO_DMA) {
1441 		tf.protocol = ATAPI_PROT_DMA;
1442 		tf.feature |= ATAPI_PKT_DMA;
1443 	} else {
1444 		tf.protocol = ATAPI_PROT_PIO;
1445 		tf.lbam = SCSI_SENSE_BUFFERSIZE;
1446 		tf.lbah = 0;
1447 	}
1448 
1449 	return ata_exec_internal(dev, &tf, cdb, DMA_FROM_DEVICE,
1450 				 sense_buf, SCSI_SENSE_BUFFERSIZE, 0);
1451 }
1452 
1453 /**
1454  *	ata_eh_analyze_serror - analyze SError for a failed port
1455  *	@link: ATA link to analyze SError for
1456  *
1457  *	Analyze SError if available and further determine cause of
1458  *	failure.
1459  *
1460  *	LOCKING:
1461  *	None.
1462  */
1463 static void ata_eh_analyze_serror(struct ata_link *link)
1464 {
1465 	struct ata_eh_context *ehc = &link->eh_context;
1466 	u32 serror = ehc->i.serror;
1467 	unsigned int err_mask = 0, action = 0;
1468 	u32 hotplug_mask;
1469 
1470 	if (serror & (SERR_PERSISTENT | SERR_DATA)) {
1471 		err_mask |= AC_ERR_ATA_BUS;
1472 		action |= ATA_EH_RESET;
1473 	}
1474 	if (serror & SERR_PROTOCOL) {
1475 		err_mask |= AC_ERR_HSM;
1476 		action |= ATA_EH_RESET;
1477 	}
1478 	if (serror & SERR_INTERNAL) {
1479 		err_mask |= AC_ERR_SYSTEM;
1480 		action |= ATA_EH_RESET;
1481 	}
1482 
1483 	/* Determine whether a hotplug event has occurred.  Both
1484 	 * SError.N/X are considered hotplug events for enabled or
1485 	 * host links.  For disabled PMP links, only N bit is
1486 	 * considered as X bit is left at 1 for link plugging.
1487 	 */
1488 	hotplug_mask = 0;
1489 
1490 	if (!(link->flags & ATA_LFLAG_DISABLED) || ata_is_host_link(link))
1491 		hotplug_mask = SERR_PHYRDY_CHG | SERR_DEV_XCHG;
1492 	else
1493 		hotplug_mask = SERR_PHYRDY_CHG;
1494 
1495 	if (serror & hotplug_mask)
1496 		ata_ehi_hotplugged(&ehc->i);
1497 
1498 	ehc->i.err_mask |= err_mask;
1499 	ehc->i.action |= action;
1500 }
1501 
1502 /**
1503  *	ata_eh_analyze_ncq_error - analyze NCQ error
1504  *	@link: ATA link to analyze NCQ error for
1505  *
1506  *	Read log page 10h, determine the offending qc and acquire
1507  *	error status TF.  For NCQ device errors, all LLDDs have to do
1508  *	is setting AC_ERR_DEV in ehi->err_mask.  This function takes
1509  *	care of the rest.
1510  *
1511  *	LOCKING:
1512  *	Kernel thread context (may sleep).
1513  */
1514 void ata_eh_analyze_ncq_error(struct ata_link *link)
1515 {
1516 	struct ata_port *ap = link->ap;
1517 	struct ata_eh_context *ehc = &link->eh_context;
1518 	struct ata_device *dev = link->device;
1519 	struct ata_queued_cmd *qc;
1520 	struct ata_taskfile tf;
1521 	int tag, rc;
1522 
1523 	/* if frozen, we can't do much */
1524 	if (ap->pflags & ATA_PFLAG_FROZEN)
1525 		return;
1526 
1527 	/* is it NCQ device error? */
1528 	if (!link->sactive || !(ehc->i.err_mask & AC_ERR_DEV))
1529 		return;
1530 
1531 	/* has LLDD analyzed already? */
1532 	for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
1533 		qc = __ata_qc_from_tag(ap, tag);
1534 
1535 		if (!(qc->flags & ATA_QCFLAG_FAILED))
1536 			continue;
1537 
1538 		if (qc->err_mask)
1539 			return;
1540 	}
1541 
1542 	/* okay, this error is ours */
1543 	rc = ata_eh_read_log_10h(dev, &tag, &tf);
1544 	if (rc) {
1545 		ata_link_printk(link, KERN_ERR, "failed to read log page 10h "
1546 				"(errno=%d)\n", rc);
1547 		return;
1548 	}
1549 
1550 	if (!(link->sactive & (1 << tag))) {
1551 		ata_link_printk(link, KERN_ERR, "log page 10h reported "
1552 				"inactive tag %d\n", tag);
1553 		return;
1554 	}
1555 
1556 	/* we've got the perpetrator, condemn it */
1557 	qc = __ata_qc_from_tag(ap, tag);
1558 	memcpy(&qc->result_tf, &tf, sizeof(tf));
1559 	qc->result_tf.flags = ATA_TFLAG_ISADDR | ATA_TFLAG_LBA | ATA_TFLAG_LBA48;
1560 	qc->err_mask |= AC_ERR_DEV | AC_ERR_NCQ;
1561 	ehc->i.err_mask &= ~AC_ERR_DEV;
1562 }
1563 
1564 /**
1565  *	ata_eh_analyze_tf - analyze taskfile of a failed qc
1566  *	@qc: qc to analyze
1567  *	@tf: Taskfile registers to analyze
1568  *
1569  *	Analyze taskfile of @qc and further determine cause of
1570  *	failure.  This function also requests ATAPI sense data if
1571  *	avaliable.
1572  *
1573  *	LOCKING:
1574  *	Kernel thread context (may sleep).
1575  *
1576  *	RETURNS:
1577  *	Determined recovery action
1578  */
1579 static unsigned int ata_eh_analyze_tf(struct ata_queued_cmd *qc,
1580 				      const struct ata_taskfile *tf)
1581 {
1582 	unsigned int tmp, action = 0;
1583 	u8 stat = tf->command, err = tf->feature;
1584 
1585 	if ((stat & (ATA_BUSY | ATA_DRQ | ATA_DRDY)) != ATA_DRDY) {
1586 		qc->err_mask |= AC_ERR_HSM;
1587 		return ATA_EH_RESET;
1588 	}
1589 
1590 	if (stat & (ATA_ERR | ATA_DF))
1591 		qc->err_mask |= AC_ERR_DEV;
1592 	else
1593 		return 0;
1594 
1595 	switch (qc->dev->class) {
1596 	case ATA_DEV_ATA:
1597 		if (err & ATA_ICRC)
1598 			qc->err_mask |= AC_ERR_ATA_BUS;
1599 		if (err & ATA_UNC)
1600 			qc->err_mask |= AC_ERR_MEDIA;
1601 		if (err & ATA_IDNF)
1602 			qc->err_mask |= AC_ERR_INVALID;
1603 		break;
1604 
1605 	case ATA_DEV_ATAPI:
1606 		if (!(qc->ap->pflags & ATA_PFLAG_FROZEN)) {
1607 			tmp = atapi_eh_request_sense(qc->dev,
1608 						qc->scsicmd->sense_buffer,
1609 						qc->result_tf.feature >> 4);
1610 			if (!tmp) {
1611 				/* ATA_QCFLAG_SENSE_VALID is used to
1612 				 * tell atapi_qc_complete() that sense
1613 				 * data is already valid.
1614 				 *
1615 				 * TODO: interpret sense data and set
1616 				 * appropriate err_mask.
1617 				 */
1618 				qc->flags |= ATA_QCFLAG_SENSE_VALID;
1619 			} else
1620 				qc->err_mask |= tmp;
1621 		}
1622 	}
1623 
1624 	if (qc->err_mask & (AC_ERR_HSM | AC_ERR_TIMEOUT | AC_ERR_ATA_BUS))
1625 		action |= ATA_EH_RESET;
1626 
1627 	return action;
1628 }
1629 
1630 static int ata_eh_categorize_error(unsigned int eflags, unsigned int err_mask,
1631 				   int *xfer_ok)
1632 {
1633 	int base = 0;
1634 
1635 	if (!(eflags & ATA_EFLAG_DUBIOUS_XFER))
1636 		*xfer_ok = 1;
1637 
1638 	if (!*xfer_ok)
1639 		base = ATA_ECAT_DUBIOUS_NONE;
1640 
1641 	if (err_mask & AC_ERR_ATA_BUS)
1642 		return base + ATA_ECAT_ATA_BUS;
1643 
1644 	if (err_mask & AC_ERR_TIMEOUT)
1645 		return base + ATA_ECAT_TOUT_HSM;
1646 
1647 	if (eflags & ATA_EFLAG_IS_IO) {
1648 		if (err_mask & AC_ERR_HSM)
1649 			return base + ATA_ECAT_TOUT_HSM;
1650 		if ((err_mask &
1651 		     (AC_ERR_DEV|AC_ERR_MEDIA|AC_ERR_INVALID)) == AC_ERR_DEV)
1652 			return base + ATA_ECAT_UNK_DEV;
1653 	}
1654 
1655 	return 0;
1656 }
1657 
1658 struct speed_down_verdict_arg {
1659 	u64 since;
1660 	int xfer_ok;
1661 	int nr_errors[ATA_ECAT_NR];
1662 };
1663 
1664 static int speed_down_verdict_cb(struct ata_ering_entry *ent, void *void_arg)
1665 {
1666 	struct speed_down_verdict_arg *arg = void_arg;
1667 	int cat;
1668 
1669 	if (ent->timestamp < arg->since)
1670 		return -1;
1671 
1672 	cat = ata_eh_categorize_error(ent->eflags, ent->err_mask,
1673 				      &arg->xfer_ok);
1674 	arg->nr_errors[cat]++;
1675 
1676 	return 0;
1677 }
1678 
1679 /**
1680  *	ata_eh_speed_down_verdict - Determine speed down verdict
1681  *	@dev: Device of interest
1682  *
1683  *	This function examines error ring of @dev and determines
1684  *	whether NCQ needs to be turned off, transfer speed should be
1685  *	stepped down, or falling back to PIO is necessary.
1686  *
1687  *	ECAT_ATA_BUS	: ATA_BUS error for any command
1688  *
1689  *	ECAT_TOUT_HSM	: TIMEOUT for any command or HSM violation for
1690  *			  IO commands
1691  *
1692  *	ECAT_UNK_DEV	: Unknown DEV error for IO commands
1693  *
1694  *	ECAT_DUBIOUS_*	: Identical to above three but occurred while
1695  *			  data transfer hasn't been verified.
1696  *
1697  *	Verdicts are
1698  *
1699  *	NCQ_OFF		: Turn off NCQ.
1700  *
1701  *	SPEED_DOWN	: Speed down transfer speed but don't fall back
1702  *			  to PIO.
1703  *
1704  *	FALLBACK_TO_PIO	: Fall back to PIO.
1705  *
1706  *	Even if multiple verdicts are returned, only one action is
1707  *	taken per error.  An action triggered by non-DUBIOUS errors
1708  *	clears ering, while one triggered by DUBIOUS_* errors doesn't.
1709  *	This is to expedite speed down decisions right after device is
1710  *	initially configured.
1711  *
1712  *	The followings are speed down rules.  #1 and #2 deal with
1713  *	DUBIOUS errors.
1714  *
1715  *	1. If more than one DUBIOUS_ATA_BUS or DUBIOUS_TOUT_HSM errors
1716  *	   occurred during last 5 mins, SPEED_DOWN and FALLBACK_TO_PIO.
1717  *
1718  *	2. If more than one DUBIOUS_TOUT_HSM or DUBIOUS_UNK_DEV errors
1719  *	   occurred during last 5 mins, NCQ_OFF.
1720  *
1721  *	3. If more than 8 ATA_BUS, TOUT_HSM or UNK_DEV errors
1722  *	   ocurred during last 5 mins, FALLBACK_TO_PIO
1723  *
1724  *	4. If more than 3 TOUT_HSM or UNK_DEV errors occurred
1725  *	   during last 10 mins, NCQ_OFF.
1726  *
1727  *	5. If more than 3 ATA_BUS or TOUT_HSM errors, or more than 6
1728  *	   UNK_DEV errors occurred during last 10 mins, SPEED_DOWN.
1729  *
1730  *	LOCKING:
1731  *	Inherited from caller.
1732  *
1733  *	RETURNS:
1734  *	OR of ATA_EH_SPDN_* flags.
1735  */
1736 static unsigned int ata_eh_speed_down_verdict(struct ata_device *dev)
1737 {
1738 	const u64 j5mins = 5LLU * 60 * HZ, j10mins = 10LLU * 60 * HZ;
1739 	u64 j64 = get_jiffies_64();
1740 	struct speed_down_verdict_arg arg;
1741 	unsigned int verdict = 0;
1742 
1743 	/* scan past 5 mins of error history */
1744 	memset(&arg, 0, sizeof(arg));
1745 	arg.since = j64 - min(j64, j5mins);
1746 	ata_ering_map(&dev->ering, speed_down_verdict_cb, &arg);
1747 
1748 	if (arg.nr_errors[ATA_ECAT_DUBIOUS_ATA_BUS] +
1749 	    arg.nr_errors[ATA_ECAT_DUBIOUS_TOUT_HSM] > 1)
1750 		verdict |= ATA_EH_SPDN_SPEED_DOWN |
1751 			ATA_EH_SPDN_FALLBACK_TO_PIO | ATA_EH_SPDN_KEEP_ERRORS;
1752 
1753 	if (arg.nr_errors[ATA_ECAT_DUBIOUS_TOUT_HSM] +
1754 	    arg.nr_errors[ATA_ECAT_DUBIOUS_UNK_DEV] > 1)
1755 		verdict |= ATA_EH_SPDN_NCQ_OFF | ATA_EH_SPDN_KEEP_ERRORS;
1756 
1757 	if (arg.nr_errors[ATA_ECAT_ATA_BUS] +
1758 	    arg.nr_errors[ATA_ECAT_TOUT_HSM] +
1759 	    arg.nr_errors[ATA_ECAT_UNK_DEV] > 6)
1760 		verdict |= ATA_EH_SPDN_FALLBACK_TO_PIO;
1761 
1762 	/* scan past 10 mins of error history */
1763 	memset(&arg, 0, sizeof(arg));
1764 	arg.since = j64 - min(j64, j10mins);
1765 	ata_ering_map(&dev->ering, speed_down_verdict_cb, &arg);
1766 
1767 	if (arg.nr_errors[ATA_ECAT_TOUT_HSM] +
1768 	    arg.nr_errors[ATA_ECAT_UNK_DEV] > 3)
1769 		verdict |= ATA_EH_SPDN_NCQ_OFF;
1770 
1771 	if (arg.nr_errors[ATA_ECAT_ATA_BUS] +
1772 	    arg.nr_errors[ATA_ECAT_TOUT_HSM] > 3 ||
1773 	    arg.nr_errors[ATA_ECAT_UNK_DEV] > 6)
1774 		verdict |= ATA_EH_SPDN_SPEED_DOWN;
1775 
1776 	return verdict;
1777 }
1778 
1779 /**
1780  *	ata_eh_speed_down - record error and speed down if necessary
1781  *	@dev: Failed device
1782  *	@eflags: mask of ATA_EFLAG_* flags
1783  *	@err_mask: err_mask of the error
1784  *
1785  *	Record error and examine error history to determine whether
1786  *	adjusting transmission speed is necessary.  It also sets
1787  *	transmission limits appropriately if such adjustment is
1788  *	necessary.
1789  *
1790  *	LOCKING:
1791  *	Kernel thread context (may sleep).
1792  *
1793  *	RETURNS:
1794  *	Determined recovery action.
1795  */
1796 static unsigned int ata_eh_speed_down(struct ata_device *dev,
1797 				unsigned int eflags, unsigned int err_mask)
1798 {
1799 	struct ata_link *link = ata_dev_phys_link(dev);
1800 	int xfer_ok = 0;
1801 	unsigned int verdict;
1802 	unsigned int action = 0;
1803 
1804 	/* don't bother if Cat-0 error */
1805 	if (ata_eh_categorize_error(eflags, err_mask, &xfer_ok) == 0)
1806 		return 0;
1807 
1808 	/* record error and determine whether speed down is necessary */
1809 	ata_ering_record(&dev->ering, eflags, err_mask);
1810 	verdict = ata_eh_speed_down_verdict(dev);
1811 
1812 	/* turn off NCQ? */
1813 	if ((verdict & ATA_EH_SPDN_NCQ_OFF) &&
1814 	    (dev->flags & (ATA_DFLAG_PIO | ATA_DFLAG_NCQ |
1815 			   ATA_DFLAG_NCQ_OFF)) == ATA_DFLAG_NCQ) {
1816 		dev->flags |= ATA_DFLAG_NCQ_OFF;
1817 		ata_dev_printk(dev, KERN_WARNING,
1818 			       "NCQ disabled due to excessive errors\n");
1819 		goto done;
1820 	}
1821 
1822 	/* speed down? */
1823 	if (verdict & ATA_EH_SPDN_SPEED_DOWN) {
1824 		/* speed down SATA link speed if possible */
1825 		if (sata_down_spd_limit(link) == 0) {
1826 			action |= ATA_EH_RESET;
1827 			goto done;
1828 		}
1829 
1830 		/* lower transfer mode */
1831 		if (dev->spdn_cnt < 2) {
1832 			static const int dma_dnxfer_sel[] =
1833 				{ ATA_DNXFER_DMA, ATA_DNXFER_40C };
1834 			static const int pio_dnxfer_sel[] =
1835 				{ ATA_DNXFER_PIO, ATA_DNXFER_FORCE_PIO0 };
1836 			int sel;
1837 
1838 			if (dev->xfer_shift != ATA_SHIFT_PIO)
1839 				sel = dma_dnxfer_sel[dev->spdn_cnt];
1840 			else
1841 				sel = pio_dnxfer_sel[dev->spdn_cnt];
1842 
1843 			dev->spdn_cnt++;
1844 
1845 			if (ata_down_xfermask_limit(dev, sel) == 0) {
1846 				action |= ATA_EH_RESET;
1847 				goto done;
1848 			}
1849 		}
1850 	}
1851 
1852 	/* Fall back to PIO?  Slowing down to PIO is meaningless for
1853 	 * SATA ATA devices.  Consider it only for PATA and SATAPI.
1854 	 */
1855 	if ((verdict & ATA_EH_SPDN_FALLBACK_TO_PIO) && (dev->spdn_cnt >= 2) &&
1856 	    (link->ap->cbl != ATA_CBL_SATA || dev->class == ATA_DEV_ATAPI) &&
1857 	    (dev->xfer_shift != ATA_SHIFT_PIO)) {
1858 		if (ata_down_xfermask_limit(dev, ATA_DNXFER_FORCE_PIO) == 0) {
1859 			dev->spdn_cnt = 0;
1860 			action |= ATA_EH_RESET;
1861 			goto done;
1862 		}
1863 	}
1864 
1865 	return 0;
1866  done:
1867 	/* device has been slowed down, blow error history */
1868 	if (!(verdict & ATA_EH_SPDN_KEEP_ERRORS))
1869 		ata_ering_clear(&dev->ering);
1870 	return action;
1871 }
1872 
1873 /**
1874  *	ata_eh_link_autopsy - analyze error and determine recovery action
1875  *	@link: host link to perform autopsy on
1876  *
1877  *	Analyze why @link failed and determine which recovery actions
1878  *	are needed.  This function also sets more detailed AC_ERR_*
1879  *	values and fills sense data for ATAPI CHECK SENSE.
1880  *
1881  *	LOCKING:
1882  *	Kernel thread context (may sleep).
1883  */
1884 static void ata_eh_link_autopsy(struct ata_link *link)
1885 {
1886 	struct ata_port *ap = link->ap;
1887 	struct ata_eh_context *ehc = &link->eh_context;
1888 	struct ata_device *dev;
1889 	unsigned int all_err_mask = 0, eflags = 0;
1890 	int tag;
1891 	u32 serror;
1892 	int rc;
1893 
1894 	DPRINTK("ENTER\n");
1895 
1896 	if (ehc->i.flags & ATA_EHI_NO_AUTOPSY)
1897 		return;
1898 
1899 	/* obtain and analyze SError */
1900 	rc = sata_scr_read(link, SCR_ERROR, &serror);
1901 	if (rc == 0) {
1902 		ehc->i.serror |= serror;
1903 		ata_eh_analyze_serror(link);
1904 	} else if (rc != -EOPNOTSUPP) {
1905 		/* SError read failed, force reset and probing */
1906 		ehc->i.probe_mask |= ATA_ALL_DEVICES;
1907 		ehc->i.action |= ATA_EH_RESET;
1908 		ehc->i.err_mask |= AC_ERR_OTHER;
1909 	}
1910 
1911 	/* analyze NCQ failure */
1912 	ata_eh_analyze_ncq_error(link);
1913 
1914 	/* any real error trumps AC_ERR_OTHER */
1915 	if (ehc->i.err_mask & ~AC_ERR_OTHER)
1916 		ehc->i.err_mask &= ~AC_ERR_OTHER;
1917 
1918 	all_err_mask |= ehc->i.err_mask;
1919 
1920 	for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
1921 		struct ata_queued_cmd *qc = __ata_qc_from_tag(ap, tag);
1922 
1923 		if (!(qc->flags & ATA_QCFLAG_FAILED) ||
1924 		    ata_dev_phys_link(qc->dev) != link)
1925 			continue;
1926 
1927 		/* inherit upper level err_mask */
1928 		qc->err_mask |= ehc->i.err_mask;
1929 
1930 		/* analyze TF */
1931 		ehc->i.action |= ata_eh_analyze_tf(qc, &qc->result_tf);
1932 
1933 		/* DEV errors are probably spurious in case of ATA_BUS error */
1934 		if (qc->err_mask & AC_ERR_ATA_BUS)
1935 			qc->err_mask &= ~(AC_ERR_DEV | AC_ERR_MEDIA |
1936 					  AC_ERR_INVALID);
1937 
1938 		/* any real error trumps unknown error */
1939 		if (qc->err_mask & ~AC_ERR_OTHER)
1940 			qc->err_mask &= ~AC_ERR_OTHER;
1941 
1942 		/* SENSE_VALID trumps dev/unknown error and revalidation */
1943 		if (qc->flags & ATA_QCFLAG_SENSE_VALID)
1944 			qc->err_mask &= ~(AC_ERR_DEV | AC_ERR_OTHER);
1945 
1946 		/* determine whether the command is worth retrying */
1947 		if (!(qc->err_mask & AC_ERR_INVALID) &&
1948 		    ((qc->flags & ATA_QCFLAG_IO) || qc->err_mask != AC_ERR_DEV))
1949 			qc->flags |= ATA_QCFLAG_RETRY;
1950 
1951 		/* accumulate error info */
1952 		ehc->i.dev = qc->dev;
1953 		all_err_mask |= qc->err_mask;
1954 		if (qc->flags & ATA_QCFLAG_IO)
1955 			eflags |= ATA_EFLAG_IS_IO;
1956 	}
1957 
1958 	/* enforce default EH actions */
1959 	if (ap->pflags & ATA_PFLAG_FROZEN ||
1960 	    all_err_mask & (AC_ERR_HSM | AC_ERR_TIMEOUT))
1961 		ehc->i.action |= ATA_EH_RESET;
1962 	else if (((eflags & ATA_EFLAG_IS_IO) && all_err_mask) ||
1963 		 (!(eflags & ATA_EFLAG_IS_IO) && (all_err_mask & ~AC_ERR_DEV)))
1964 		ehc->i.action |= ATA_EH_REVALIDATE;
1965 
1966 	/* If we have offending qcs and the associated failed device,
1967 	 * perform per-dev EH action only on the offending device.
1968 	 */
1969 	if (ehc->i.dev) {
1970 		ehc->i.dev_action[ehc->i.dev->devno] |=
1971 			ehc->i.action & ATA_EH_PERDEV_MASK;
1972 		ehc->i.action &= ~ATA_EH_PERDEV_MASK;
1973 	}
1974 
1975 	/* propagate timeout to host link */
1976 	if ((all_err_mask & AC_ERR_TIMEOUT) && !ata_is_host_link(link))
1977 		ap->link.eh_context.i.err_mask |= AC_ERR_TIMEOUT;
1978 
1979 	/* record error and consider speeding down */
1980 	dev = ehc->i.dev;
1981 	if (!dev && ((ata_link_max_devices(link) == 1 &&
1982 		      ata_dev_enabled(link->device))))
1983 	    dev = link->device;
1984 
1985 	if (dev) {
1986 		if (dev->flags & ATA_DFLAG_DUBIOUS_XFER)
1987 			eflags |= ATA_EFLAG_DUBIOUS_XFER;
1988 		ehc->i.action |= ata_eh_speed_down(dev, eflags, all_err_mask);
1989 	}
1990 
1991 	DPRINTK("EXIT\n");
1992 }
1993 
1994 /**
1995  *	ata_eh_autopsy - analyze error and determine recovery action
1996  *	@ap: host port to perform autopsy on
1997  *
1998  *	Analyze all links of @ap and determine why they failed and
1999  *	which recovery actions are needed.
2000  *
2001  *	LOCKING:
2002  *	Kernel thread context (may sleep).
2003  */
2004 void ata_eh_autopsy(struct ata_port *ap)
2005 {
2006 	struct ata_link *link;
2007 
2008 	ata_port_for_each_link(link, ap)
2009 		ata_eh_link_autopsy(link);
2010 
2011 	/* Handle the frigging slave link.  Autopsy is done similarly
2012 	 * but actions and flags are transferred over to the master
2013 	 * link and handled from there.
2014 	 */
2015 	if (ap->slave_link) {
2016 		struct ata_eh_context *mehc = &ap->link.eh_context;
2017 		struct ata_eh_context *sehc = &ap->slave_link->eh_context;
2018 
2019 		/* transfer control flags from master to slave */
2020 		sehc->i.flags |= mehc->i.flags & ATA_EHI_TO_SLAVE_MASK;
2021 
2022 		/* perform autopsy on the slave link */
2023 		ata_eh_link_autopsy(ap->slave_link);
2024 
2025 		/* transfer actions from slave to master and clear slave */
2026 		ata_eh_about_to_do(ap->slave_link, NULL, ATA_EH_ALL_ACTIONS);
2027 		mehc->i.action		|= sehc->i.action;
2028 		mehc->i.dev_action[1]	|= sehc->i.dev_action[1];
2029 		mehc->i.flags		|= sehc->i.flags;
2030 		ata_eh_done(ap->slave_link, NULL, ATA_EH_ALL_ACTIONS);
2031 	}
2032 
2033 	/* Autopsy of fanout ports can affect host link autopsy.
2034 	 * Perform host link autopsy last.
2035 	 */
2036 	if (sata_pmp_attached(ap))
2037 		ata_eh_link_autopsy(&ap->link);
2038 }
2039 
2040 /**
2041  *	ata_eh_link_report - report error handling to user
2042  *	@link: ATA link EH is going on
2043  *
2044  *	Report EH to user.
2045  *
2046  *	LOCKING:
2047  *	None.
2048  */
2049 static void ata_eh_link_report(struct ata_link *link)
2050 {
2051 	struct ata_port *ap = link->ap;
2052 	struct ata_eh_context *ehc = &link->eh_context;
2053 	const char *frozen, *desc;
2054 	char tries_buf[6];
2055 	int tag, nr_failed = 0;
2056 
2057 	if (ehc->i.flags & ATA_EHI_QUIET)
2058 		return;
2059 
2060 	desc = NULL;
2061 	if (ehc->i.desc[0] != '\0')
2062 		desc = ehc->i.desc;
2063 
2064 	for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
2065 		struct ata_queued_cmd *qc = __ata_qc_from_tag(ap, tag);
2066 
2067 		if (!(qc->flags & ATA_QCFLAG_FAILED) ||
2068 		    ata_dev_phys_link(qc->dev) != link ||
2069 		    ((qc->flags & ATA_QCFLAG_QUIET) &&
2070 		     qc->err_mask == AC_ERR_DEV))
2071 			continue;
2072 		if (qc->flags & ATA_QCFLAG_SENSE_VALID && !qc->err_mask)
2073 			continue;
2074 
2075 		nr_failed++;
2076 	}
2077 
2078 	if (!nr_failed && !ehc->i.err_mask)
2079 		return;
2080 
2081 	frozen = "";
2082 	if (ap->pflags & ATA_PFLAG_FROZEN)
2083 		frozen = " frozen";
2084 
2085 	memset(tries_buf, 0, sizeof(tries_buf));
2086 	if (ap->eh_tries < ATA_EH_MAX_TRIES)
2087 		snprintf(tries_buf, sizeof(tries_buf) - 1, " t%d",
2088 			 ap->eh_tries);
2089 
2090 	if (ehc->i.dev) {
2091 		ata_dev_printk(ehc->i.dev, KERN_ERR, "exception Emask 0x%x "
2092 			       "SAct 0x%x SErr 0x%x action 0x%x%s%s\n",
2093 			       ehc->i.err_mask, link->sactive, ehc->i.serror,
2094 			       ehc->i.action, frozen, tries_buf);
2095 		if (desc)
2096 			ata_dev_printk(ehc->i.dev, KERN_ERR, "%s\n", desc);
2097 	} else {
2098 		ata_link_printk(link, KERN_ERR, "exception Emask 0x%x "
2099 				"SAct 0x%x SErr 0x%x action 0x%x%s%s\n",
2100 				ehc->i.err_mask, link->sactive, ehc->i.serror,
2101 				ehc->i.action, frozen, tries_buf);
2102 		if (desc)
2103 			ata_link_printk(link, KERN_ERR, "%s\n", desc);
2104 	}
2105 
2106 	if (ehc->i.serror)
2107 		ata_link_printk(link, KERN_ERR,
2108 		  "SError: { %s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s}\n",
2109 		  ehc->i.serror & SERR_DATA_RECOVERED ? "RecovData " : "",
2110 		  ehc->i.serror & SERR_COMM_RECOVERED ? "RecovComm " : "",
2111 		  ehc->i.serror & SERR_DATA ? "UnrecovData " : "",
2112 		  ehc->i.serror & SERR_PERSISTENT ? "Persist " : "",
2113 		  ehc->i.serror & SERR_PROTOCOL ? "Proto " : "",
2114 		  ehc->i.serror & SERR_INTERNAL ? "HostInt " : "",
2115 		  ehc->i.serror & SERR_PHYRDY_CHG ? "PHYRdyChg " : "",
2116 		  ehc->i.serror & SERR_PHY_INT_ERR ? "PHYInt " : "",
2117 		  ehc->i.serror & SERR_COMM_WAKE ? "CommWake " : "",
2118 		  ehc->i.serror & SERR_10B_8B_ERR ? "10B8B " : "",
2119 		  ehc->i.serror & SERR_DISPARITY ? "Dispar " : "",
2120 		  ehc->i.serror & SERR_CRC ? "BadCRC " : "",
2121 		  ehc->i.serror & SERR_HANDSHAKE ? "Handshk " : "",
2122 		  ehc->i.serror & SERR_LINK_SEQ_ERR ? "LinkSeq " : "",
2123 		  ehc->i.serror & SERR_TRANS_ST_ERROR ? "TrStaTrns " : "",
2124 		  ehc->i.serror & SERR_UNRECOG_FIS ? "UnrecFIS " : "",
2125 		  ehc->i.serror & SERR_DEV_XCHG ? "DevExch " : "");
2126 
2127 	for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
2128 		struct ata_queued_cmd *qc = __ata_qc_from_tag(ap, tag);
2129 		struct ata_taskfile *cmd = &qc->tf, *res = &qc->result_tf;
2130 		const u8 *cdb = qc->cdb;
2131 		char data_buf[20] = "";
2132 		char cdb_buf[70] = "";
2133 
2134 		if (!(qc->flags & ATA_QCFLAG_FAILED) ||
2135 		    ata_dev_phys_link(qc->dev) != link || !qc->err_mask)
2136 			continue;
2137 
2138 		if (qc->dma_dir != DMA_NONE) {
2139 			static const char *dma_str[] = {
2140 				[DMA_BIDIRECTIONAL]	= "bidi",
2141 				[DMA_TO_DEVICE]		= "out",
2142 				[DMA_FROM_DEVICE]	= "in",
2143 			};
2144 			static const char *prot_str[] = {
2145 				[ATA_PROT_PIO]		= "pio",
2146 				[ATA_PROT_DMA]		= "dma",
2147 				[ATA_PROT_NCQ]		= "ncq",
2148 				[ATAPI_PROT_PIO]	= "pio",
2149 				[ATAPI_PROT_DMA]	= "dma",
2150 			};
2151 
2152 			snprintf(data_buf, sizeof(data_buf), " %s %u %s",
2153 				 prot_str[qc->tf.protocol], qc->nbytes,
2154 				 dma_str[qc->dma_dir]);
2155 		}
2156 
2157 		if (ata_is_atapi(qc->tf.protocol))
2158 			snprintf(cdb_buf, sizeof(cdb_buf),
2159 				 "cdb %02x %02x %02x %02x %02x %02x %02x %02x  "
2160 				 "%02x %02x %02x %02x %02x %02x %02x %02x\n         ",
2161 				 cdb[0], cdb[1], cdb[2], cdb[3],
2162 				 cdb[4], cdb[5], cdb[6], cdb[7],
2163 				 cdb[8], cdb[9], cdb[10], cdb[11],
2164 				 cdb[12], cdb[13], cdb[14], cdb[15]);
2165 
2166 		ata_dev_printk(qc->dev, KERN_ERR,
2167 			"cmd %02x/%02x:%02x:%02x:%02x:%02x/%02x:%02x:%02x:%02x:%02x/%02x "
2168 			"tag %d%s\n         %s"
2169 			"res %02x/%02x:%02x:%02x:%02x:%02x/%02x:%02x:%02x:%02x:%02x/%02x "
2170 			"Emask 0x%x (%s)%s\n",
2171 			cmd->command, cmd->feature, cmd->nsect,
2172 			cmd->lbal, cmd->lbam, cmd->lbah,
2173 			cmd->hob_feature, cmd->hob_nsect,
2174 			cmd->hob_lbal, cmd->hob_lbam, cmd->hob_lbah,
2175 			cmd->device, qc->tag, data_buf, cdb_buf,
2176 			res->command, res->feature, res->nsect,
2177 			res->lbal, res->lbam, res->lbah,
2178 			res->hob_feature, res->hob_nsect,
2179 			res->hob_lbal, res->hob_lbam, res->hob_lbah,
2180 			res->device, qc->err_mask, ata_err_string(qc->err_mask),
2181 			qc->err_mask & AC_ERR_NCQ ? " <F>" : "");
2182 
2183 		if (res->command & (ATA_BUSY | ATA_DRDY | ATA_DF | ATA_DRQ |
2184 				    ATA_ERR)) {
2185 			if (res->command & ATA_BUSY)
2186 				ata_dev_printk(qc->dev, KERN_ERR,
2187 				  "status: { Busy }\n");
2188 			else
2189 				ata_dev_printk(qc->dev, KERN_ERR,
2190 				  "status: { %s%s%s%s}\n",
2191 				  res->command & ATA_DRDY ? "DRDY " : "",
2192 				  res->command & ATA_DF ? "DF " : "",
2193 				  res->command & ATA_DRQ ? "DRQ " : "",
2194 				  res->command & ATA_ERR ? "ERR " : "");
2195 		}
2196 
2197 		if (cmd->command != ATA_CMD_PACKET &&
2198 		    (res->feature & (ATA_ICRC | ATA_UNC | ATA_IDNF |
2199 				     ATA_ABORTED)))
2200 			ata_dev_printk(qc->dev, KERN_ERR,
2201 			  "error: { %s%s%s%s}\n",
2202 			  res->feature & ATA_ICRC ? "ICRC " : "",
2203 			  res->feature & ATA_UNC ? "UNC " : "",
2204 			  res->feature & ATA_IDNF ? "IDNF " : "",
2205 			  res->feature & ATA_ABORTED ? "ABRT " : "");
2206 	}
2207 }
2208 
2209 /**
2210  *	ata_eh_report - report error handling to user
2211  *	@ap: ATA port to report EH about
2212  *
2213  *	Report EH to user.
2214  *
2215  *	LOCKING:
2216  *	None.
2217  */
2218 void ata_eh_report(struct ata_port *ap)
2219 {
2220 	struct ata_link *link;
2221 
2222 	__ata_port_for_each_link(link, ap)
2223 		ata_eh_link_report(link);
2224 }
2225 
2226 static int ata_do_reset(struct ata_link *link, ata_reset_fn_t reset,
2227 			unsigned int *classes, unsigned long deadline,
2228 			bool clear_classes)
2229 {
2230 	struct ata_device *dev;
2231 
2232 	if (clear_classes)
2233 		ata_link_for_each_dev(dev, link)
2234 			classes[dev->devno] = ATA_DEV_UNKNOWN;
2235 
2236 	return reset(link, classes, deadline);
2237 }
2238 
2239 static int ata_eh_followup_srst_needed(struct ata_link *link,
2240 				       int rc, const unsigned int *classes)
2241 {
2242 	if ((link->flags & ATA_LFLAG_NO_SRST) || ata_link_offline(link))
2243 		return 0;
2244 	if (rc == -EAGAIN)
2245 		return 1;
2246 	if (sata_pmp_supported(link->ap) && ata_is_host_link(link))
2247 		return 1;
2248 	return 0;
2249 }
2250 
2251 int ata_eh_reset(struct ata_link *link, int classify,
2252 		 ata_prereset_fn_t prereset, ata_reset_fn_t softreset,
2253 		 ata_reset_fn_t hardreset, ata_postreset_fn_t postreset)
2254 {
2255 	struct ata_port *ap = link->ap;
2256 	struct ata_link *slave = ap->slave_link;
2257 	struct ata_eh_context *ehc = &link->eh_context;
2258 	struct ata_eh_context *sehc = &slave->eh_context;
2259 	unsigned int *classes = ehc->classes;
2260 	unsigned int lflags = link->flags;
2261 	int verbose = !(ehc->i.flags & ATA_EHI_QUIET);
2262 	int max_tries = 0, try = 0;
2263 	struct ata_link *failed_link;
2264 	struct ata_device *dev;
2265 	unsigned long deadline, now;
2266 	ata_reset_fn_t reset;
2267 	unsigned long flags;
2268 	u32 sstatus;
2269 	int nr_unknown, rc;
2270 
2271 	/*
2272 	 * Prepare to reset
2273 	 */
2274 	while (ata_eh_reset_timeouts[max_tries] != ULONG_MAX)
2275 		max_tries++;
2276 	if (link->flags & ATA_LFLAG_NO_HRST)
2277 		hardreset = NULL;
2278 	if (link->flags & ATA_LFLAG_NO_SRST)
2279 		softreset = NULL;
2280 
2281 	/* make sure each reset attemp is at least COOL_DOWN apart */
2282 	if (ehc->i.flags & ATA_EHI_DID_RESET) {
2283 		now = jiffies;
2284 		WARN_ON(time_after(ehc->last_reset, now));
2285 		deadline = ata_deadline(ehc->last_reset,
2286 					ATA_EH_RESET_COOL_DOWN);
2287 		if (time_before(now, deadline))
2288 			schedule_timeout_uninterruptible(deadline - now);
2289 	}
2290 
2291 	spin_lock_irqsave(ap->lock, flags);
2292 	ap->pflags |= ATA_PFLAG_RESETTING;
2293 	spin_unlock_irqrestore(ap->lock, flags);
2294 
2295 	ata_eh_about_to_do(link, NULL, ATA_EH_RESET);
2296 
2297 	ata_link_for_each_dev(dev, link) {
2298 		/* If we issue an SRST then an ATA drive (not ATAPI)
2299 		 * may change configuration and be in PIO0 timing. If
2300 		 * we do a hard reset (or are coming from power on)
2301 		 * this is true for ATA or ATAPI. Until we've set a
2302 		 * suitable controller mode we should not touch the
2303 		 * bus as we may be talking too fast.
2304 		 */
2305 		dev->pio_mode = XFER_PIO_0;
2306 
2307 		/* If the controller has a pio mode setup function
2308 		 * then use it to set the chipset to rights. Don't
2309 		 * touch the DMA setup as that will be dealt with when
2310 		 * configuring devices.
2311 		 */
2312 		if (ap->ops->set_piomode)
2313 			ap->ops->set_piomode(ap, dev);
2314 	}
2315 
2316 	/* prefer hardreset */
2317 	reset = NULL;
2318 	ehc->i.action &= ~ATA_EH_RESET;
2319 	if (hardreset) {
2320 		reset = hardreset;
2321 		ehc->i.action |= ATA_EH_HARDRESET;
2322 	} else if (softreset) {
2323 		reset = softreset;
2324 		ehc->i.action |= ATA_EH_SOFTRESET;
2325 	}
2326 
2327 	if (prereset) {
2328 		unsigned long deadline = ata_deadline(jiffies,
2329 						      ATA_EH_PRERESET_TIMEOUT);
2330 
2331 		if (slave) {
2332 			sehc->i.action &= ~ATA_EH_RESET;
2333 			sehc->i.action |= ehc->i.action;
2334 		}
2335 
2336 		rc = prereset(link, deadline);
2337 
2338 		/* If present, do prereset on slave link too.  Reset
2339 		 * is skipped iff both master and slave links report
2340 		 * -ENOENT or clear ATA_EH_RESET.
2341 		 */
2342 		if (slave && (rc == 0 || rc == -ENOENT)) {
2343 			int tmp;
2344 
2345 			tmp = prereset(slave, deadline);
2346 			if (tmp != -ENOENT)
2347 				rc = tmp;
2348 
2349 			ehc->i.action |= sehc->i.action;
2350 		}
2351 
2352 		if (rc) {
2353 			if (rc == -ENOENT) {
2354 				ata_link_printk(link, KERN_DEBUG,
2355 						"port disabled. ignoring.\n");
2356 				ehc->i.action &= ~ATA_EH_RESET;
2357 
2358 				ata_link_for_each_dev(dev, link)
2359 					classes[dev->devno] = ATA_DEV_NONE;
2360 
2361 				rc = 0;
2362 			} else
2363 				ata_link_printk(link, KERN_ERR,
2364 					"prereset failed (errno=%d)\n", rc);
2365 			goto out;
2366 		}
2367 
2368 		/* prereset() might have cleared ATA_EH_RESET.  If so,
2369 		 * bang classes and return.
2370 		 */
2371 		if (reset && !(ehc->i.action & ATA_EH_RESET)) {
2372 			ata_link_for_each_dev(dev, link)
2373 				classes[dev->devno] = ATA_DEV_NONE;
2374 			rc = 0;
2375 			goto out;
2376 		}
2377 	}
2378 
2379  retry:
2380 	/*
2381 	 * Perform reset
2382 	 */
2383 	if (ata_is_host_link(link))
2384 		ata_eh_freeze_port(ap);
2385 
2386 	deadline = ata_deadline(jiffies, ata_eh_reset_timeouts[try++]);
2387 
2388 	if (reset) {
2389 		if (verbose)
2390 			ata_link_printk(link, KERN_INFO, "%s resetting link\n",
2391 					reset == softreset ? "soft" : "hard");
2392 
2393 		/* mark that this EH session started with reset */
2394 		ehc->last_reset = jiffies;
2395 		if (reset == hardreset)
2396 			ehc->i.flags |= ATA_EHI_DID_HARDRESET;
2397 		else
2398 			ehc->i.flags |= ATA_EHI_DID_SOFTRESET;
2399 
2400 		rc = ata_do_reset(link, reset, classes, deadline, true);
2401 		if (rc && rc != -EAGAIN) {
2402 			failed_link = link;
2403 			goto fail;
2404 		}
2405 
2406 		/* hardreset slave link if existent */
2407 		if (slave && reset == hardreset) {
2408 			int tmp;
2409 
2410 			if (verbose)
2411 				ata_link_printk(slave, KERN_INFO,
2412 						"hard resetting link\n");
2413 
2414 			ata_eh_about_to_do(slave, NULL, ATA_EH_RESET);
2415 			tmp = ata_do_reset(slave, reset, classes, deadline,
2416 					   false);
2417 			switch (tmp) {
2418 			case -EAGAIN:
2419 				rc = -EAGAIN;
2420 			case 0:
2421 				break;
2422 			default:
2423 				failed_link = slave;
2424 				rc = tmp;
2425 				goto fail;
2426 			}
2427 		}
2428 
2429 		/* perform follow-up SRST if necessary */
2430 		if (reset == hardreset &&
2431 		    ata_eh_followup_srst_needed(link, rc, classes)) {
2432 			reset = softreset;
2433 
2434 			if (!reset) {
2435 				ata_link_printk(link, KERN_ERR,
2436 						"follow-up softreset required "
2437 						"but no softreset avaliable\n");
2438 				failed_link = link;
2439 				rc = -EINVAL;
2440 				goto fail;
2441 			}
2442 
2443 			ata_eh_about_to_do(link, NULL, ATA_EH_RESET);
2444 			rc = ata_do_reset(link, reset, classes, deadline, true);
2445 		}
2446 	} else {
2447 		if (verbose)
2448 			ata_link_printk(link, KERN_INFO, "no reset method "
2449 					"available, skipping reset\n");
2450 		if (!(lflags & ATA_LFLAG_ASSUME_CLASS))
2451 			lflags |= ATA_LFLAG_ASSUME_ATA;
2452 	}
2453 
2454 	/*
2455 	 * Post-reset processing
2456 	 */
2457 	ata_link_for_each_dev(dev, link) {
2458 		/* After the reset, the device state is PIO 0 and the
2459 		 * controller state is undefined.  Reset also wakes up
2460 		 * drives from sleeping mode.
2461 		 */
2462 		dev->pio_mode = XFER_PIO_0;
2463 		dev->flags &= ~ATA_DFLAG_SLEEPING;
2464 
2465 		if (!ata_phys_link_offline(ata_dev_phys_link(dev))) {
2466 			/* apply class override */
2467 			if (lflags & ATA_LFLAG_ASSUME_ATA)
2468 				classes[dev->devno] = ATA_DEV_ATA;
2469 			else if (lflags & ATA_LFLAG_ASSUME_SEMB)
2470 				classes[dev->devno] = ATA_DEV_SEMB_UNSUP;
2471 		} else
2472 			classes[dev->devno] = ATA_DEV_NONE;
2473 	}
2474 
2475 	/* record current link speed */
2476 	if (sata_scr_read(link, SCR_STATUS, &sstatus) == 0)
2477 		link->sata_spd = (sstatus >> 4) & 0xf;
2478 	if (slave && sata_scr_read(slave, SCR_STATUS, &sstatus) == 0)
2479 		slave->sata_spd = (sstatus >> 4) & 0xf;
2480 
2481 	/* thaw the port */
2482 	if (ata_is_host_link(link))
2483 		ata_eh_thaw_port(ap);
2484 
2485 	/* postreset() should clear hardware SError.  Although SError
2486 	 * is cleared during link resume, clearing SError here is
2487 	 * necessary as some PHYs raise hotplug events after SRST.
2488 	 * This introduces race condition where hotplug occurs between
2489 	 * reset and here.  This race is mediated by cross checking
2490 	 * link onlineness and classification result later.
2491 	 */
2492 	if (postreset) {
2493 		postreset(link, classes);
2494 		if (slave)
2495 			postreset(slave, classes);
2496 	}
2497 
2498 	/* clear cached SError */
2499 	spin_lock_irqsave(link->ap->lock, flags);
2500 	link->eh_info.serror = 0;
2501 	if (slave)
2502 		slave->eh_info.serror = 0;
2503 	spin_unlock_irqrestore(link->ap->lock, flags);
2504 
2505 	/* Make sure onlineness and classification result correspond.
2506 	 * Hotplug could have happened during reset and some
2507 	 * controllers fail to wait while a drive is spinning up after
2508 	 * being hotplugged causing misdetection.  By cross checking
2509 	 * link onlineness and classification result, those conditions
2510 	 * can be reliably detected and retried.
2511 	 */
2512 	nr_unknown = 0;
2513 	ata_link_for_each_dev(dev, link) {
2514 		/* convert all ATA_DEV_UNKNOWN to ATA_DEV_NONE */
2515 		if (classes[dev->devno] == ATA_DEV_UNKNOWN) {
2516 			classes[dev->devno] = ATA_DEV_NONE;
2517 			if (ata_phys_link_online(ata_dev_phys_link(dev)))
2518 				nr_unknown++;
2519 		}
2520 	}
2521 
2522 	if (classify && nr_unknown) {
2523 		if (try < max_tries) {
2524 			ata_link_printk(link, KERN_WARNING, "link online but "
2525 				       "device misclassified, retrying\n");
2526 			failed_link = link;
2527 			rc = -EAGAIN;
2528 			goto fail;
2529 		}
2530 		ata_link_printk(link, KERN_WARNING,
2531 			       "link online but device misclassified, "
2532 			       "device detection might fail\n");
2533 	}
2534 
2535 	/* reset successful, schedule revalidation */
2536 	ata_eh_done(link, NULL, ATA_EH_RESET);
2537 	if (slave)
2538 		ata_eh_done(slave, NULL, ATA_EH_RESET);
2539 	ehc->last_reset = jiffies;	/* update to completion time */
2540 	ehc->i.action |= ATA_EH_REVALIDATE;
2541 
2542 	rc = 0;
2543  out:
2544 	/* clear hotplug flag */
2545 	ehc->i.flags &= ~ATA_EHI_HOTPLUGGED;
2546 	if (slave)
2547 		sehc->i.flags &= ~ATA_EHI_HOTPLUGGED;
2548 
2549 	spin_lock_irqsave(ap->lock, flags);
2550 	ap->pflags &= ~ATA_PFLAG_RESETTING;
2551 	spin_unlock_irqrestore(ap->lock, flags);
2552 
2553 	return rc;
2554 
2555  fail:
2556 	/* if SCR isn't accessible on a fan-out port, PMP needs to be reset */
2557 	if (!ata_is_host_link(link) &&
2558 	    sata_scr_read(link, SCR_STATUS, &sstatus))
2559 		rc = -ERESTART;
2560 
2561 	if (rc == -ERESTART || try >= max_tries)
2562 		goto out;
2563 
2564 	now = jiffies;
2565 	if (time_before(now, deadline)) {
2566 		unsigned long delta = deadline - now;
2567 
2568 		ata_link_printk(failed_link, KERN_WARNING,
2569 			"reset failed (errno=%d), retrying in %u secs\n",
2570 			rc, DIV_ROUND_UP(jiffies_to_msecs(delta), 1000));
2571 
2572 		while (delta)
2573 			delta = schedule_timeout_uninterruptible(delta);
2574 	}
2575 
2576 	if (try == max_tries - 1) {
2577 		sata_down_spd_limit(link);
2578 		if (slave)
2579 			sata_down_spd_limit(slave);
2580 	} else if (rc == -EPIPE)
2581 		sata_down_spd_limit(failed_link);
2582 
2583 	if (hardreset)
2584 		reset = hardreset;
2585 	goto retry;
2586 }
2587 
2588 static inline void ata_eh_pull_park_action(struct ata_port *ap)
2589 {
2590 	struct ata_link *link;
2591 	struct ata_device *dev;
2592 	unsigned long flags;
2593 
2594 	/*
2595 	 * This function can be thought of as an extended version of
2596 	 * ata_eh_about_to_do() specially crafted to accommodate the
2597 	 * requirements of ATA_EH_PARK handling. Since the EH thread
2598 	 * does not leave the do {} while () loop in ata_eh_recover as
2599 	 * long as the timeout for a park request to *one* device on
2600 	 * the port has not expired, and since we still want to pick
2601 	 * up park requests to other devices on the same port or
2602 	 * timeout updates for the same device, we have to pull
2603 	 * ATA_EH_PARK actions from eh_info into eh_context.i
2604 	 * ourselves at the beginning of each pass over the loop.
2605 	 *
2606 	 * Additionally, all write accesses to &ap->park_req_pending
2607 	 * through INIT_COMPLETION() (see below) or complete_all()
2608 	 * (see ata_scsi_park_store()) are protected by the host lock.
2609 	 * As a result we have that park_req_pending.done is zero on
2610 	 * exit from this function, i.e. when ATA_EH_PARK actions for
2611 	 * *all* devices on port ap have been pulled into the
2612 	 * respective eh_context structs. If, and only if,
2613 	 * park_req_pending.done is non-zero by the time we reach
2614 	 * wait_for_completion_timeout(), another ATA_EH_PARK action
2615 	 * has been scheduled for at least one of the devices on port
2616 	 * ap and we have to cycle over the do {} while () loop in
2617 	 * ata_eh_recover() again.
2618 	 */
2619 
2620 	spin_lock_irqsave(ap->lock, flags);
2621 	INIT_COMPLETION(ap->park_req_pending);
2622 	ata_port_for_each_link(link, ap) {
2623 		ata_link_for_each_dev(dev, link) {
2624 			struct ata_eh_info *ehi = &link->eh_info;
2625 
2626 			link->eh_context.i.dev_action[dev->devno] |=
2627 				ehi->dev_action[dev->devno] & ATA_EH_PARK;
2628 			ata_eh_clear_action(link, dev, ehi, ATA_EH_PARK);
2629 		}
2630 	}
2631 	spin_unlock_irqrestore(ap->lock, flags);
2632 }
2633 
2634 static void ata_eh_park_issue_cmd(struct ata_device *dev, int park)
2635 {
2636 	struct ata_eh_context *ehc = &dev->link->eh_context;
2637 	struct ata_taskfile tf;
2638 	unsigned int err_mask;
2639 
2640 	ata_tf_init(dev, &tf);
2641 	if (park) {
2642 		ehc->unloaded_mask |= 1 << dev->devno;
2643 		tf.command = ATA_CMD_IDLEIMMEDIATE;
2644 		tf.feature = 0x44;
2645 		tf.lbal = 0x4c;
2646 		tf.lbam = 0x4e;
2647 		tf.lbah = 0x55;
2648 	} else {
2649 		ehc->unloaded_mask &= ~(1 << dev->devno);
2650 		tf.command = ATA_CMD_CHK_POWER;
2651 	}
2652 
2653 	tf.flags |= ATA_TFLAG_DEVICE | ATA_TFLAG_ISADDR;
2654 	tf.protocol |= ATA_PROT_NODATA;
2655 	err_mask = ata_exec_internal(dev, &tf, NULL, DMA_NONE, NULL, 0, 0);
2656 	if (park && (err_mask || tf.lbal != 0xc4)) {
2657 		ata_dev_printk(dev, KERN_ERR, "head unload failed!\n");
2658 		ehc->unloaded_mask &= ~(1 << dev->devno);
2659 	}
2660 }
2661 
2662 static int ata_eh_revalidate_and_attach(struct ata_link *link,
2663 					struct ata_device **r_failed_dev)
2664 {
2665 	struct ata_port *ap = link->ap;
2666 	struct ata_eh_context *ehc = &link->eh_context;
2667 	struct ata_device *dev;
2668 	unsigned int new_mask = 0;
2669 	unsigned long flags;
2670 	int rc = 0;
2671 
2672 	DPRINTK("ENTER\n");
2673 
2674 	/* For PATA drive side cable detection to work, IDENTIFY must
2675 	 * be done backwards such that PDIAG- is released by the slave
2676 	 * device before the master device is identified.
2677 	 */
2678 	ata_link_for_each_dev_reverse(dev, link) {
2679 		unsigned int action = ata_eh_dev_action(dev);
2680 		unsigned int readid_flags = 0;
2681 
2682 		if (ehc->i.flags & ATA_EHI_DID_RESET)
2683 			readid_flags |= ATA_READID_POSTRESET;
2684 
2685 		if ((action & ATA_EH_REVALIDATE) && ata_dev_enabled(dev)) {
2686 			WARN_ON(dev->class == ATA_DEV_PMP);
2687 
2688 			if (ata_phys_link_offline(ata_dev_phys_link(dev))) {
2689 				rc = -EIO;
2690 				goto err;
2691 			}
2692 
2693 			ata_eh_about_to_do(link, dev, ATA_EH_REVALIDATE);
2694 			rc = ata_dev_revalidate(dev, ehc->classes[dev->devno],
2695 						readid_flags);
2696 			if (rc)
2697 				goto err;
2698 
2699 			ata_eh_done(link, dev, ATA_EH_REVALIDATE);
2700 
2701 			/* Configuration may have changed, reconfigure
2702 			 * transfer mode.
2703 			 */
2704 			ehc->i.flags |= ATA_EHI_SETMODE;
2705 
2706 			/* schedule the scsi_rescan_device() here */
2707 			queue_work(ata_aux_wq, &(ap->scsi_rescan_task));
2708 		} else if (dev->class == ATA_DEV_UNKNOWN &&
2709 			   ehc->tries[dev->devno] &&
2710 			   ata_class_enabled(ehc->classes[dev->devno])) {
2711 			dev->class = ehc->classes[dev->devno];
2712 
2713 			if (dev->class == ATA_DEV_PMP)
2714 				rc = sata_pmp_attach(dev);
2715 			else
2716 				rc = ata_dev_read_id(dev, &dev->class,
2717 						     readid_flags, dev->id);
2718 			switch (rc) {
2719 			case 0:
2720 				new_mask |= 1 << dev->devno;
2721 				break;
2722 			case -ENOENT:
2723 				/* IDENTIFY was issued to non-existent
2724 				 * device.  No need to reset.  Just
2725 				 * thaw and kill the device.
2726 				 */
2727 				ata_eh_thaw_port(ap);
2728 				dev->class = ATA_DEV_UNKNOWN;
2729 				break;
2730 			default:
2731 				dev->class = ATA_DEV_UNKNOWN;
2732 				goto err;
2733 			}
2734 		}
2735 	}
2736 
2737 	/* PDIAG- should have been released, ask cable type if post-reset */
2738 	if ((ehc->i.flags & ATA_EHI_DID_RESET) && ata_is_host_link(link)) {
2739 		if (ap->ops->cable_detect)
2740 			ap->cbl = ap->ops->cable_detect(ap);
2741 		ata_force_cbl(ap);
2742 	}
2743 
2744 	/* Configure new devices forward such that user doesn't see
2745 	 * device detection messages backwards.
2746 	 */
2747 	ata_link_for_each_dev(dev, link) {
2748 		if (!(new_mask & (1 << dev->devno)) ||
2749 		    dev->class == ATA_DEV_PMP)
2750 			continue;
2751 
2752 		ehc->i.flags |= ATA_EHI_PRINTINFO;
2753 		rc = ata_dev_configure(dev);
2754 		ehc->i.flags &= ~ATA_EHI_PRINTINFO;
2755 		if (rc)
2756 			goto err;
2757 
2758 		spin_lock_irqsave(ap->lock, flags);
2759 		ap->pflags |= ATA_PFLAG_SCSI_HOTPLUG;
2760 		spin_unlock_irqrestore(ap->lock, flags);
2761 
2762 		/* new device discovered, configure xfermode */
2763 		ehc->i.flags |= ATA_EHI_SETMODE;
2764 	}
2765 
2766 	return 0;
2767 
2768  err:
2769 	*r_failed_dev = dev;
2770 	DPRINTK("EXIT rc=%d\n", rc);
2771 	return rc;
2772 }
2773 
2774 /**
2775  *	ata_set_mode - Program timings and issue SET FEATURES - XFER
2776  *	@link: link on which timings will be programmed
2777  *	@r_failed_dev: out paramter for failed device
2778  *
2779  *	Set ATA device disk transfer mode (PIO3, UDMA6, etc.).  If
2780  *	ata_set_mode() fails, pointer to the failing device is
2781  *	returned in @r_failed_dev.
2782  *
2783  *	LOCKING:
2784  *	PCI/etc. bus probe sem.
2785  *
2786  *	RETURNS:
2787  *	0 on success, negative errno otherwise
2788  */
2789 int ata_set_mode(struct ata_link *link, struct ata_device **r_failed_dev)
2790 {
2791 	struct ata_port *ap = link->ap;
2792 	struct ata_device *dev;
2793 	int rc;
2794 
2795 	/* if data transfer is verified, clear DUBIOUS_XFER on ering top */
2796 	ata_link_for_each_dev(dev, link) {
2797 		if (!ata_dev_enabled(dev))
2798 			continue;
2799 
2800 		if (!(dev->flags & ATA_DFLAG_DUBIOUS_XFER)) {
2801 			struct ata_ering_entry *ent;
2802 
2803 			ent = ata_ering_top(&dev->ering);
2804 			if (ent)
2805 				ent->eflags &= ~ATA_EFLAG_DUBIOUS_XFER;
2806 		}
2807 	}
2808 
2809 	/* has private set_mode? */
2810 	if (ap->ops->set_mode)
2811 		rc = ap->ops->set_mode(link, r_failed_dev);
2812 	else
2813 		rc = ata_do_set_mode(link, r_failed_dev);
2814 
2815 	/* if transfer mode has changed, set DUBIOUS_XFER on device */
2816 	ata_link_for_each_dev(dev, link) {
2817 		struct ata_eh_context *ehc = &link->eh_context;
2818 		u8 saved_xfer_mode = ehc->saved_xfer_mode[dev->devno];
2819 		u8 saved_ncq = !!(ehc->saved_ncq_enabled & (1 << dev->devno));
2820 
2821 		if (!ata_dev_enabled(dev))
2822 			continue;
2823 
2824 		if (dev->xfer_mode != saved_xfer_mode ||
2825 		    ata_ncq_enabled(dev) != saved_ncq)
2826 			dev->flags |= ATA_DFLAG_DUBIOUS_XFER;
2827 	}
2828 
2829 	return rc;
2830 }
2831 
2832 /**
2833  *	atapi_eh_clear_ua - Clear ATAPI UNIT ATTENTION after reset
2834  *	@dev: ATAPI device to clear UA for
2835  *
2836  *	Resets and other operations can make an ATAPI device raise
2837  *	UNIT ATTENTION which causes the next operation to fail.  This
2838  *	function clears UA.
2839  *
2840  *	LOCKING:
2841  *	EH context (may sleep).
2842  *
2843  *	RETURNS:
2844  *	0 on success, -errno on failure.
2845  */
2846 static int atapi_eh_clear_ua(struct ata_device *dev)
2847 {
2848 	int i;
2849 
2850 	for (i = 0; i < ATA_EH_UA_TRIES; i++) {
2851 		u8 sense_buffer[SCSI_SENSE_BUFFERSIZE];
2852 		u8 sense_key = 0;
2853 		unsigned int err_mask;
2854 
2855 		err_mask = atapi_eh_tur(dev, &sense_key);
2856 		if (err_mask != 0 && err_mask != AC_ERR_DEV) {
2857 			ata_dev_printk(dev, KERN_WARNING, "TEST_UNIT_READY "
2858 				"failed (err_mask=0x%x)\n", err_mask);
2859 			return -EIO;
2860 		}
2861 
2862 		if (!err_mask || sense_key != UNIT_ATTENTION)
2863 			return 0;
2864 
2865 		err_mask = atapi_eh_request_sense(dev, sense_buffer, sense_key);
2866 		if (err_mask) {
2867 			ata_dev_printk(dev, KERN_WARNING, "failed to clear "
2868 				"UNIT ATTENTION (err_mask=0x%x)\n", err_mask);
2869 			return -EIO;
2870 		}
2871 	}
2872 
2873 	ata_dev_printk(dev, KERN_WARNING,
2874 		"UNIT ATTENTION persists after %d tries\n", ATA_EH_UA_TRIES);
2875 
2876 	return 0;
2877 }
2878 
2879 static int ata_link_nr_enabled(struct ata_link *link)
2880 {
2881 	struct ata_device *dev;
2882 	int cnt = 0;
2883 
2884 	ata_link_for_each_dev(dev, link)
2885 		if (ata_dev_enabled(dev))
2886 			cnt++;
2887 	return cnt;
2888 }
2889 
2890 static int ata_link_nr_vacant(struct ata_link *link)
2891 {
2892 	struct ata_device *dev;
2893 	int cnt = 0;
2894 
2895 	ata_link_for_each_dev(dev, link)
2896 		if (dev->class == ATA_DEV_UNKNOWN)
2897 			cnt++;
2898 	return cnt;
2899 }
2900 
2901 static int ata_eh_skip_recovery(struct ata_link *link)
2902 {
2903 	struct ata_port *ap = link->ap;
2904 	struct ata_eh_context *ehc = &link->eh_context;
2905 	struct ata_device *dev;
2906 
2907 	/* skip disabled links */
2908 	if (link->flags & ATA_LFLAG_DISABLED)
2909 		return 1;
2910 
2911 	/* thaw frozen port and recover failed devices */
2912 	if ((ap->pflags & ATA_PFLAG_FROZEN) || ata_link_nr_enabled(link))
2913 		return 0;
2914 
2915 	/* reset at least once if reset is requested */
2916 	if ((ehc->i.action & ATA_EH_RESET) &&
2917 	    !(ehc->i.flags & ATA_EHI_DID_RESET))
2918 		return 0;
2919 
2920 	/* skip if class codes for all vacant slots are ATA_DEV_NONE */
2921 	ata_link_for_each_dev(dev, link) {
2922 		if (dev->class == ATA_DEV_UNKNOWN &&
2923 		    ehc->classes[dev->devno] != ATA_DEV_NONE)
2924 			return 0;
2925 	}
2926 
2927 	return 1;
2928 }
2929 
2930 static int ata_eh_schedule_probe(struct ata_device *dev)
2931 {
2932 	struct ata_eh_context *ehc = &dev->link->eh_context;
2933 
2934 	if (!(ehc->i.probe_mask & (1 << dev->devno)) ||
2935 	    (ehc->did_probe_mask & (1 << dev->devno)))
2936 		return 0;
2937 
2938 	ata_eh_detach_dev(dev);
2939 	ata_dev_init(dev);
2940 	ehc->did_probe_mask |= (1 << dev->devno);
2941 	ehc->i.action |= ATA_EH_RESET;
2942 	ehc->saved_xfer_mode[dev->devno] = 0;
2943 	ehc->saved_ncq_enabled &= ~(1 << dev->devno);
2944 
2945 	return 1;
2946 }
2947 
2948 static int ata_eh_handle_dev_fail(struct ata_device *dev, int err)
2949 {
2950 	struct ata_eh_context *ehc = &dev->link->eh_context;
2951 
2952 	ehc->tries[dev->devno]--;
2953 
2954 	switch (err) {
2955 	case -ENODEV:
2956 		/* device missing or wrong IDENTIFY data, schedule probing */
2957 		ehc->i.probe_mask |= (1 << dev->devno);
2958 	case -EINVAL:
2959 		/* give it just one more chance */
2960 		ehc->tries[dev->devno] = min(ehc->tries[dev->devno], 1);
2961 	case -EIO:
2962 		if (ehc->tries[dev->devno] == 1 && dev->pio_mode > XFER_PIO_0) {
2963 			/* This is the last chance, better to slow
2964 			 * down than lose it.
2965 			 */
2966 			sata_down_spd_limit(ata_dev_phys_link(dev));
2967 			ata_down_xfermask_limit(dev, ATA_DNXFER_PIO);
2968 		}
2969 	}
2970 
2971 	if (ata_dev_enabled(dev) && !ehc->tries[dev->devno]) {
2972 		/* disable device if it has used up all its chances */
2973 		ata_dev_disable(dev);
2974 
2975 		/* detach if offline */
2976 		if (ata_phys_link_offline(ata_dev_phys_link(dev)))
2977 			ata_eh_detach_dev(dev);
2978 
2979 		/* schedule probe if necessary */
2980 		if (ata_eh_schedule_probe(dev)) {
2981 			ehc->tries[dev->devno] = ATA_EH_DEV_TRIES;
2982 			memset(ehc->cmd_timeout_idx[dev->devno], 0,
2983 			       sizeof(ehc->cmd_timeout_idx[dev->devno]));
2984 		}
2985 
2986 		return 1;
2987 	} else {
2988 		ehc->i.action |= ATA_EH_RESET;
2989 		return 0;
2990 	}
2991 }
2992 
2993 /**
2994  *	ata_eh_recover - recover host port after error
2995  *	@ap: host port to recover
2996  *	@prereset: prereset method (can be NULL)
2997  *	@softreset: softreset method (can be NULL)
2998  *	@hardreset: hardreset method (can be NULL)
2999  *	@postreset: postreset method (can be NULL)
3000  *	@r_failed_link: out parameter for failed link
3001  *
3002  *	This is the alpha and omega, eum and yang, heart and soul of
3003  *	libata exception handling.  On entry, actions required to
3004  *	recover each link and hotplug requests are recorded in the
3005  *	link's eh_context.  This function executes all the operations
3006  *	with appropriate retrials and fallbacks to resurrect failed
3007  *	devices, detach goners and greet newcomers.
3008  *
3009  *	LOCKING:
3010  *	Kernel thread context (may sleep).
3011  *
3012  *	RETURNS:
3013  *	0 on success, -errno on failure.
3014  */
3015 int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
3016 		   ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
3017 		   ata_postreset_fn_t postreset,
3018 		   struct ata_link **r_failed_link)
3019 {
3020 	struct ata_link *link;
3021 	struct ata_device *dev;
3022 	int nr_failed_devs;
3023 	int rc;
3024 	unsigned long flags, deadline;
3025 
3026 	DPRINTK("ENTER\n");
3027 
3028 	/* prep for recovery */
3029 	ata_port_for_each_link(link, ap) {
3030 		struct ata_eh_context *ehc = &link->eh_context;
3031 
3032 		/* re-enable link? */
3033 		if (ehc->i.action & ATA_EH_ENABLE_LINK) {
3034 			ata_eh_about_to_do(link, NULL, ATA_EH_ENABLE_LINK);
3035 			spin_lock_irqsave(ap->lock, flags);
3036 			link->flags &= ~ATA_LFLAG_DISABLED;
3037 			spin_unlock_irqrestore(ap->lock, flags);
3038 			ata_eh_done(link, NULL, ATA_EH_ENABLE_LINK);
3039 		}
3040 
3041 		ata_link_for_each_dev(dev, link) {
3042 			if (link->flags & ATA_LFLAG_NO_RETRY)
3043 				ehc->tries[dev->devno] = 1;
3044 			else
3045 				ehc->tries[dev->devno] = ATA_EH_DEV_TRIES;
3046 
3047 			/* collect port action mask recorded in dev actions */
3048 			ehc->i.action |= ehc->i.dev_action[dev->devno] &
3049 					 ~ATA_EH_PERDEV_MASK;
3050 			ehc->i.dev_action[dev->devno] &= ATA_EH_PERDEV_MASK;
3051 
3052 			/* process hotplug request */
3053 			if (dev->flags & ATA_DFLAG_DETACH)
3054 				ata_eh_detach_dev(dev);
3055 
3056 			/* schedule probe if necessary */
3057 			if (!ata_dev_enabled(dev))
3058 				ata_eh_schedule_probe(dev);
3059 		}
3060 	}
3061 
3062  retry:
3063 	rc = 0;
3064 	nr_failed_devs = 0;
3065 
3066 	/* if UNLOADING, finish immediately */
3067 	if (ap->pflags & ATA_PFLAG_UNLOADING)
3068 		goto out;
3069 
3070 	/* prep for EH */
3071 	ata_port_for_each_link(link, ap) {
3072 		struct ata_eh_context *ehc = &link->eh_context;
3073 
3074 		/* skip EH if possible. */
3075 		if (ata_eh_skip_recovery(link))
3076 			ehc->i.action = 0;
3077 
3078 		ata_link_for_each_dev(dev, link)
3079 			ehc->classes[dev->devno] = ATA_DEV_UNKNOWN;
3080 	}
3081 
3082 	/* reset */
3083 	ata_port_for_each_link(link, ap) {
3084 		struct ata_eh_context *ehc = &link->eh_context;
3085 
3086 		if (!(ehc->i.action & ATA_EH_RESET))
3087 			continue;
3088 
3089 		rc = ata_eh_reset(link, ata_link_nr_vacant(link),
3090 				  prereset, softreset, hardreset, postreset);
3091 		if (rc) {
3092 			ata_link_printk(link, KERN_ERR,
3093 					"reset failed, giving up\n");
3094 			goto out;
3095 		}
3096 	}
3097 
3098 	do {
3099 		unsigned long now;
3100 
3101 		/*
3102 		 * clears ATA_EH_PARK in eh_info and resets
3103 		 * ap->park_req_pending
3104 		 */
3105 		ata_eh_pull_park_action(ap);
3106 
3107 		deadline = jiffies;
3108 		ata_port_for_each_link(link, ap) {
3109 			ata_link_for_each_dev(dev, link) {
3110 				struct ata_eh_context *ehc = &link->eh_context;
3111 				unsigned long tmp;
3112 
3113 				if (dev->class != ATA_DEV_ATA)
3114 					continue;
3115 				if (!(ehc->i.dev_action[dev->devno] &
3116 				      ATA_EH_PARK))
3117 					continue;
3118 				tmp = dev->unpark_deadline;
3119 				if (time_before(deadline, tmp))
3120 					deadline = tmp;
3121 				else if (time_before_eq(tmp, jiffies))
3122 					continue;
3123 				if (ehc->unloaded_mask & (1 << dev->devno))
3124 					continue;
3125 
3126 				ata_eh_park_issue_cmd(dev, 1);
3127 			}
3128 		}
3129 
3130 		now = jiffies;
3131 		if (time_before_eq(deadline, now))
3132 			break;
3133 
3134 		deadline = wait_for_completion_timeout(&ap->park_req_pending,
3135 						       deadline - now);
3136 	} while (deadline);
3137 	ata_port_for_each_link(link, ap) {
3138 		ata_link_for_each_dev(dev, link) {
3139 			if (!(link->eh_context.unloaded_mask &
3140 			      (1 << dev->devno)))
3141 				continue;
3142 
3143 			ata_eh_park_issue_cmd(dev, 0);
3144 			ata_eh_done(link, dev, ATA_EH_PARK);
3145 		}
3146 	}
3147 
3148 	/* the rest */
3149 	ata_port_for_each_link(link, ap) {
3150 		struct ata_eh_context *ehc = &link->eh_context;
3151 
3152 		/* revalidate existing devices and attach new ones */
3153 		rc = ata_eh_revalidate_and_attach(link, &dev);
3154 		if (rc)
3155 			goto dev_fail;
3156 
3157 		/* if PMP got attached, return, pmp EH will take care of it */
3158 		if (link->device->class == ATA_DEV_PMP) {
3159 			ehc->i.action = 0;
3160 			return 0;
3161 		}
3162 
3163 		/* configure transfer mode if necessary */
3164 		if (ehc->i.flags & ATA_EHI_SETMODE) {
3165 			rc = ata_set_mode(link, &dev);
3166 			if (rc)
3167 				goto dev_fail;
3168 			ehc->i.flags &= ~ATA_EHI_SETMODE;
3169 		}
3170 
3171 		/* If reset has been issued, clear UA to avoid
3172 		 * disrupting the current users of the device.
3173 		 */
3174 		if (ehc->i.flags & ATA_EHI_DID_RESET) {
3175 			ata_link_for_each_dev(dev, link) {
3176 				if (dev->class != ATA_DEV_ATAPI)
3177 					continue;
3178 				rc = atapi_eh_clear_ua(dev);
3179 				if (rc)
3180 					goto dev_fail;
3181 			}
3182 		}
3183 
3184 		/* configure link power saving */
3185 		if (ehc->i.action & ATA_EH_LPM)
3186 			ata_link_for_each_dev(dev, link)
3187 				ata_dev_enable_pm(dev, ap->pm_policy);
3188 
3189 		/* this link is okay now */
3190 		ehc->i.flags = 0;
3191 		continue;
3192 
3193 dev_fail:
3194 		nr_failed_devs++;
3195 		ata_eh_handle_dev_fail(dev, rc);
3196 
3197 		if (ap->pflags & ATA_PFLAG_FROZEN) {
3198 			/* PMP reset requires working host port.
3199 			 * Can't retry if it's frozen.
3200 			 */
3201 			if (sata_pmp_attached(ap))
3202 				goto out;
3203 			break;
3204 		}
3205 	}
3206 
3207 	if (nr_failed_devs)
3208 		goto retry;
3209 
3210  out:
3211 	if (rc && r_failed_link)
3212 		*r_failed_link = link;
3213 
3214 	DPRINTK("EXIT, rc=%d\n", rc);
3215 	return rc;
3216 }
3217 
3218 /**
3219  *	ata_eh_finish - finish up EH
3220  *	@ap: host port to finish EH for
3221  *
3222  *	Recovery is complete.  Clean up EH states and retry or finish
3223  *	failed qcs.
3224  *
3225  *	LOCKING:
3226  *	None.
3227  */
3228 void ata_eh_finish(struct ata_port *ap)
3229 {
3230 	int tag;
3231 
3232 	/* retry or finish qcs */
3233 	for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
3234 		struct ata_queued_cmd *qc = __ata_qc_from_tag(ap, tag);
3235 
3236 		if (!(qc->flags & ATA_QCFLAG_FAILED))
3237 			continue;
3238 
3239 		if (qc->err_mask) {
3240 			/* FIXME: Once EH migration is complete,
3241 			 * generate sense data in this function,
3242 			 * considering both err_mask and tf.
3243 			 */
3244 			if (qc->flags & ATA_QCFLAG_RETRY)
3245 				ata_eh_qc_retry(qc);
3246 			else
3247 				ata_eh_qc_complete(qc);
3248 		} else {
3249 			if (qc->flags & ATA_QCFLAG_SENSE_VALID) {
3250 				ata_eh_qc_complete(qc);
3251 			} else {
3252 				/* feed zero TF to sense generation */
3253 				memset(&qc->result_tf, 0, sizeof(qc->result_tf));
3254 				ata_eh_qc_retry(qc);
3255 			}
3256 		}
3257 	}
3258 
3259 	/* make sure nr_active_links is zero after EH */
3260 	WARN_ON(ap->nr_active_links);
3261 	ap->nr_active_links = 0;
3262 }
3263 
3264 /**
3265  *	ata_do_eh - do standard error handling
3266  *	@ap: host port to handle error for
3267  *
3268  *	@prereset: prereset method (can be NULL)
3269  *	@softreset: softreset method (can be NULL)
3270  *	@hardreset: hardreset method (can be NULL)
3271  *	@postreset: postreset method (can be NULL)
3272  *
3273  *	Perform standard error handling sequence.
3274  *
3275  *	LOCKING:
3276  *	Kernel thread context (may sleep).
3277  */
3278 void ata_do_eh(struct ata_port *ap, ata_prereset_fn_t prereset,
3279 	       ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
3280 	       ata_postreset_fn_t postreset)
3281 {
3282 	struct ata_device *dev;
3283 	int rc;
3284 
3285 	ata_eh_autopsy(ap);
3286 	ata_eh_report(ap);
3287 
3288 	rc = ata_eh_recover(ap, prereset, softreset, hardreset, postreset,
3289 			    NULL);
3290 	if (rc) {
3291 		ata_link_for_each_dev(dev, &ap->link)
3292 			ata_dev_disable(dev);
3293 	}
3294 
3295 	ata_eh_finish(ap);
3296 }
3297 
3298 /**
3299  *	ata_std_error_handler - standard error handler
3300  *	@ap: host port to handle error for
3301  *
3302  *	Standard error handler
3303  *
3304  *	LOCKING:
3305  *	Kernel thread context (may sleep).
3306  */
3307 void ata_std_error_handler(struct ata_port *ap)
3308 {
3309 	struct ata_port_operations *ops = ap->ops;
3310 	ata_reset_fn_t hardreset = ops->hardreset;
3311 
3312 	/* ignore built-in hardreset if SCR access is not available */
3313 	if (ata_is_builtin_hardreset(hardreset) && !sata_scr_valid(&ap->link))
3314 		hardreset = NULL;
3315 
3316 	ata_do_eh(ap, ops->prereset, ops->softreset, hardreset, ops->postreset);
3317 }
3318 
3319 #ifdef CONFIG_PM
3320 /**
3321  *	ata_eh_handle_port_suspend - perform port suspend operation
3322  *	@ap: port to suspend
3323  *
3324  *	Suspend @ap.
3325  *
3326  *	LOCKING:
3327  *	Kernel thread context (may sleep).
3328  */
3329 static void ata_eh_handle_port_suspend(struct ata_port *ap)
3330 {
3331 	unsigned long flags;
3332 	int rc = 0;
3333 
3334 	/* are we suspending? */
3335 	spin_lock_irqsave(ap->lock, flags);
3336 	if (!(ap->pflags & ATA_PFLAG_PM_PENDING) ||
3337 	    ap->pm_mesg.event == PM_EVENT_ON) {
3338 		spin_unlock_irqrestore(ap->lock, flags);
3339 		return;
3340 	}
3341 	spin_unlock_irqrestore(ap->lock, flags);
3342 
3343 	WARN_ON(ap->pflags & ATA_PFLAG_SUSPENDED);
3344 
3345 	/* tell ACPI we're suspending */
3346 	rc = ata_acpi_on_suspend(ap);
3347 	if (rc)
3348 		goto out;
3349 
3350 	/* suspend */
3351 	ata_eh_freeze_port(ap);
3352 
3353 	if (ap->ops->port_suspend)
3354 		rc = ap->ops->port_suspend(ap, ap->pm_mesg);
3355 
3356 	ata_acpi_set_state(ap, PMSG_SUSPEND);
3357  out:
3358 	/* report result */
3359 	spin_lock_irqsave(ap->lock, flags);
3360 
3361 	ap->pflags &= ~ATA_PFLAG_PM_PENDING;
3362 	if (rc == 0)
3363 		ap->pflags |= ATA_PFLAG_SUSPENDED;
3364 	else if (ap->pflags & ATA_PFLAG_FROZEN)
3365 		ata_port_schedule_eh(ap);
3366 
3367 	if (ap->pm_result) {
3368 		*ap->pm_result = rc;
3369 		ap->pm_result = NULL;
3370 	}
3371 
3372 	spin_unlock_irqrestore(ap->lock, flags);
3373 
3374 	return;
3375 }
3376 
3377 /**
3378  *	ata_eh_handle_port_resume - perform port resume operation
3379  *	@ap: port to resume
3380  *
3381  *	Resume @ap.
3382  *
3383  *	LOCKING:
3384  *	Kernel thread context (may sleep).
3385  */
3386 static void ata_eh_handle_port_resume(struct ata_port *ap)
3387 {
3388 	unsigned long flags;
3389 	int rc = 0;
3390 
3391 	/* are we resuming? */
3392 	spin_lock_irqsave(ap->lock, flags);
3393 	if (!(ap->pflags & ATA_PFLAG_PM_PENDING) ||
3394 	    ap->pm_mesg.event != PM_EVENT_ON) {
3395 		spin_unlock_irqrestore(ap->lock, flags);
3396 		return;
3397 	}
3398 	spin_unlock_irqrestore(ap->lock, flags);
3399 
3400 	WARN_ON(!(ap->pflags & ATA_PFLAG_SUSPENDED));
3401 
3402 	ata_acpi_set_state(ap, PMSG_ON);
3403 
3404 	if (ap->ops->port_resume)
3405 		rc = ap->ops->port_resume(ap);
3406 
3407 	/* tell ACPI that we're resuming */
3408 	ata_acpi_on_resume(ap);
3409 
3410 	/* report result */
3411 	spin_lock_irqsave(ap->lock, flags);
3412 	ap->pflags &= ~(ATA_PFLAG_PM_PENDING | ATA_PFLAG_SUSPENDED);
3413 	if (ap->pm_result) {
3414 		*ap->pm_result = rc;
3415 		ap->pm_result = NULL;
3416 	}
3417 	spin_unlock_irqrestore(ap->lock, flags);
3418 }
3419 #endif /* CONFIG_PM */
3420