xref: /linux/drivers/ata/libata-eh.c (revision 367b8112fe2ea5c39a7bb4d263dcdd9b612fae18)
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 			/* set last reset timestamp to some time in the past */
615 			ehc->last_reset = jiffies - 60 * HZ;
616 		}
617 
618 		ap->pflags |= ATA_PFLAG_EH_IN_PROGRESS;
619 		ap->pflags &= ~ATA_PFLAG_EH_PENDING;
620 		ap->excl_link = NULL;	/* don't maintain exclusion over EH */
621 
622 		spin_unlock_irqrestore(ap->lock, flags);
623 
624 		/* invoke EH, skip if unloading or suspended */
625 		if (!(ap->pflags & (ATA_PFLAG_UNLOADING | ATA_PFLAG_SUSPENDED)))
626 			ap->ops->error_handler(ap);
627 		else
628 			ata_eh_finish(ap);
629 
630 		/* process port suspend request */
631 		ata_eh_handle_port_suspend(ap);
632 
633 		/* Exception might have happend after ->error_handler
634 		 * recovered the port but before this point.  Repeat
635 		 * EH in such case.
636 		 */
637 		spin_lock_irqsave(ap->lock, flags);
638 
639 		if (ap->pflags & ATA_PFLAG_EH_PENDING) {
640 			if (--ap->eh_tries) {
641 				spin_unlock_irqrestore(ap->lock, flags);
642 				goto repeat;
643 			}
644 			ata_port_printk(ap, KERN_ERR, "EH pending after %d "
645 					"tries, giving up\n", ATA_EH_MAX_TRIES);
646 			ap->pflags &= ~ATA_PFLAG_EH_PENDING;
647 		}
648 
649 		/* this run is complete, make sure EH info is clear */
650 		__ata_port_for_each_link(link, ap)
651 			memset(&link->eh_info, 0, sizeof(link->eh_info));
652 
653 		/* Clear host_eh_scheduled while holding ap->lock such
654 		 * that if exception occurs after this point but
655 		 * before EH completion, SCSI midlayer will
656 		 * re-initiate EH.
657 		 */
658 		host->host_eh_scheduled = 0;
659 
660 		spin_unlock_irqrestore(ap->lock, flags);
661 	} else {
662 		WARN_ON(ata_qc_from_tag(ap, ap->link.active_tag) == NULL);
663 		ap->ops->eng_timeout(ap);
664 	}
665 
666 	/* finish or retry handled scmd's and clean up */
667 	WARN_ON(host->host_failed || !list_empty(&host->eh_cmd_q));
668 
669 	scsi_eh_flush_done_q(&ap->eh_done_q);
670 
671 	/* clean up */
672 	spin_lock_irqsave(ap->lock, flags);
673 
674 	if (ap->pflags & ATA_PFLAG_LOADING)
675 		ap->pflags &= ~ATA_PFLAG_LOADING;
676 	else if (ap->pflags & ATA_PFLAG_SCSI_HOTPLUG)
677 		queue_delayed_work(ata_aux_wq, &ap->hotplug_task, 0);
678 
679 	if (ap->pflags & ATA_PFLAG_RECOVERED)
680 		ata_port_printk(ap, KERN_INFO, "EH complete\n");
681 
682 	ap->pflags &= ~(ATA_PFLAG_SCSI_HOTPLUG | ATA_PFLAG_RECOVERED);
683 
684 	/* tell wait_eh that we're done */
685 	ap->pflags &= ~ATA_PFLAG_EH_IN_PROGRESS;
686 	wake_up_all(&ap->eh_wait_q);
687 
688 	spin_unlock_irqrestore(ap->lock, flags);
689 
690 	DPRINTK("EXIT\n");
691 }
692 
693 /**
694  *	ata_port_wait_eh - Wait for the currently pending EH to complete
695  *	@ap: Port to wait EH for
696  *
697  *	Wait until the currently pending EH is complete.
698  *
699  *	LOCKING:
700  *	Kernel thread context (may sleep).
701  */
702 void ata_port_wait_eh(struct ata_port *ap)
703 {
704 	unsigned long flags;
705 	DEFINE_WAIT(wait);
706 
707  retry:
708 	spin_lock_irqsave(ap->lock, flags);
709 
710 	while (ap->pflags & (ATA_PFLAG_EH_PENDING | ATA_PFLAG_EH_IN_PROGRESS)) {
711 		prepare_to_wait(&ap->eh_wait_q, &wait, TASK_UNINTERRUPTIBLE);
712 		spin_unlock_irqrestore(ap->lock, flags);
713 		schedule();
714 		spin_lock_irqsave(ap->lock, flags);
715 	}
716 	finish_wait(&ap->eh_wait_q, &wait);
717 
718 	spin_unlock_irqrestore(ap->lock, flags);
719 
720 	/* make sure SCSI EH is complete */
721 	if (scsi_host_in_recovery(ap->scsi_host)) {
722 		msleep(10);
723 		goto retry;
724 	}
725 }
726 
727 static int ata_eh_nr_in_flight(struct ata_port *ap)
728 {
729 	unsigned int tag;
730 	int nr = 0;
731 
732 	/* count only non-internal commands */
733 	for (tag = 0; tag < ATA_MAX_QUEUE - 1; tag++)
734 		if (ata_qc_from_tag(ap, tag))
735 			nr++;
736 
737 	return nr;
738 }
739 
740 void ata_eh_fastdrain_timerfn(unsigned long arg)
741 {
742 	struct ata_port *ap = (void *)arg;
743 	unsigned long flags;
744 	int cnt;
745 
746 	spin_lock_irqsave(ap->lock, flags);
747 
748 	cnt = ata_eh_nr_in_flight(ap);
749 
750 	/* are we done? */
751 	if (!cnt)
752 		goto out_unlock;
753 
754 	if (cnt == ap->fastdrain_cnt) {
755 		unsigned int tag;
756 
757 		/* No progress during the last interval, tag all
758 		 * in-flight qcs as timed out and freeze the port.
759 		 */
760 		for (tag = 0; tag < ATA_MAX_QUEUE - 1; tag++) {
761 			struct ata_queued_cmd *qc = ata_qc_from_tag(ap, tag);
762 			if (qc)
763 				qc->err_mask |= AC_ERR_TIMEOUT;
764 		}
765 
766 		ata_port_freeze(ap);
767 	} else {
768 		/* some qcs have finished, give it another chance */
769 		ap->fastdrain_cnt = cnt;
770 		ap->fastdrain_timer.expires =
771 			ata_deadline(jiffies, ATA_EH_FASTDRAIN_INTERVAL);
772 		add_timer(&ap->fastdrain_timer);
773 	}
774 
775  out_unlock:
776 	spin_unlock_irqrestore(ap->lock, flags);
777 }
778 
779 /**
780  *	ata_eh_set_pending - set ATA_PFLAG_EH_PENDING and activate fast drain
781  *	@ap: target ATA port
782  *	@fastdrain: activate fast drain
783  *
784  *	Set ATA_PFLAG_EH_PENDING and activate fast drain if @fastdrain
785  *	is non-zero and EH wasn't pending before.  Fast drain ensures
786  *	that EH kicks in in timely manner.
787  *
788  *	LOCKING:
789  *	spin_lock_irqsave(host lock)
790  */
791 static void ata_eh_set_pending(struct ata_port *ap, int fastdrain)
792 {
793 	int cnt;
794 
795 	/* already scheduled? */
796 	if (ap->pflags & ATA_PFLAG_EH_PENDING)
797 		return;
798 
799 	ap->pflags |= ATA_PFLAG_EH_PENDING;
800 
801 	if (!fastdrain)
802 		return;
803 
804 	/* do we have in-flight qcs? */
805 	cnt = ata_eh_nr_in_flight(ap);
806 	if (!cnt)
807 		return;
808 
809 	/* activate fast drain */
810 	ap->fastdrain_cnt = cnt;
811 	ap->fastdrain_timer.expires =
812 		ata_deadline(jiffies, ATA_EH_FASTDRAIN_INTERVAL);
813 	add_timer(&ap->fastdrain_timer);
814 }
815 
816 /**
817  *	ata_qc_schedule_eh - schedule qc for error handling
818  *	@qc: command to schedule error handling for
819  *
820  *	Schedule error handling for @qc.  EH will kick in as soon as
821  *	other commands are drained.
822  *
823  *	LOCKING:
824  *	spin_lock_irqsave(host lock)
825  */
826 void ata_qc_schedule_eh(struct ata_queued_cmd *qc)
827 {
828 	struct ata_port *ap = qc->ap;
829 
830 	WARN_ON(!ap->ops->error_handler);
831 
832 	qc->flags |= ATA_QCFLAG_FAILED;
833 	ata_eh_set_pending(ap, 1);
834 
835 	/* The following will fail if timeout has already expired.
836 	 * ata_scsi_error() takes care of such scmds on EH entry.
837 	 * Note that ATA_QCFLAG_FAILED is unconditionally set after
838 	 * this function completes.
839 	 */
840 	blk_abort_request(qc->scsicmd->request);
841 }
842 
843 /**
844  *	ata_port_schedule_eh - schedule error handling without a qc
845  *	@ap: ATA port to schedule EH for
846  *
847  *	Schedule error handling for @ap.  EH will kick in as soon as
848  *	all commands are drained.
849  *
850  *	LOCKING:
851  *	spin_lock_irqsave(host lock)
852  */
853 void ata_port_schedule_eh(struct ata_port *ap)
854 {
855 	WARN_ON(!ap->ops->error_handler);
856 
857 	if (ap->pflags & ATA_PFLAG_INITIALIZING)
858 		return;
859 
860 	ata_eh_set_pending(ap, 1);
861 	scsi_schedule_eh(ap->scsi_host);
862 
863 	DPRINTK("port EH scheduled\n");
864 }
865 
866 static int ata_do_link_abort(struct ata_port *ap, struct ata_link *link)
867 {
868 	int tag, nr_aborted = 0;
869 
870 	WARN_ON(!ap->ops->error_handler);
871 
872 	/* we're gonna abort all commands, no need for fast drain */
873 	ata_eh_set_pending(ap, 0);
874 
875 	for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
876 		struct ata_queued_cmd *qc = ata_qc_from_tag(ap, tag);
877 
878 		if (qc && (!link || qc->dev->link == link)) {
879 			qc->flags |= ATA_QCFLAG_FAILED;
880 			ata_qc_complete(qc);
881 			nr_aborted++;
882 		}
883 	}
884 
885 	if (!nr_aborted)
886 		ata_port_schedule_eh(ap);
887 
888 	return nr_aborted;
889 }
890 
891 /**
892  *	ata_link_abort - abort all qc's on the link
893  *	@link: ATA link to abort qc's for
894  *
895  *	Abort all active qc's active on @link and schedule EH.
896  *
897  *	LOCKING:
898  *	spin_lock_irqsave(host lock)
899  *
900  *	RETURNS:
901  *	Number of aborted qc's.
902  */
903 int ata_link_abort(struct ata_link *link)
904 {
905 	return ata_do_link_abort(link->ap, link);
906 }
907 
908 /**
909  *	ata_port_abort - abort all qc's on the port
910  *	@ap: ATA port to abort qc's for
911  *
912  *	Abort all active qc's of @ap and schedule EH.
913  *
914  *	LOCKING:
915  *	spin_lock_irqsave(host_set lock)
916  *
917  *	RETURNS:
918  *	Number of aborted qc's.
919  */
920 int ata_port_abort(struct ata_port *ap)
921 {
922 	return ata_do_link_abort(ap, NULL);
923 }
924 
925 /**
926  *	__ata_port_freeze - freeze port
927  *	@ap: ATA port to freeze
928  *
929  *	This function is called when HSM violation or some other
930  *	condition disrupts normal operation of the port.  Frozen port
931  *	is not allowed to perform any operation until the port is
932  *	thawed, which usually follows a successful reset.
933  *
934  *	ap->ops->freeze() callback can be used for freezing the port
935  *	hardware-wise (e.g. mask interrupt and stop DMA engine).  If a
936  *	port cannot be frozen hardware-wise, the interrupt handler
937  *	must ack and clear interrupts unconditionally while the port
938  *	is frozen.
939  *
940  *	LOCKING:
941  *	spin_lock_irqsave(host lock)
942  */
943 static void __ata_port_freeze(struct ata_port *ap)
944 {
945 	WARN_ON(!ap->ops->error_handler);
946 
947 	if (ap->ops->freeze)
948 		ap->ops->freeze(ap);
949 
950 	ap->pflags |= ATA_PFLAG_FROZEN;
951 
952 	DPRINTK("ata%u port frozen\n", ap->print_id);
953 }
954 
955 /**
956  *	ata_port_freeze - abort & freeze port
957  *	@ap: ATA port to freeze
958  *
959  *	Abort and freeze @ap.
960  *
961  *	LOCKING:
962  *	spin_lock_irqsave(host lock)
963  *
964  *	RETURNS:
965  *	Number of aborted commands.
966  */
967 int ata_port_freeze(struct ata_port *ap)
968 {
969 	int nr_aborted;
970 
971 	WARN_ON(!ap->ops->error_handler);
972 
973 	nr_aborted = ata_port_abort(ap);
974 	__ata_port_freeze(ap);
975 
976 	return nr_aborted;
977 }
978 
979 /**
980  *	sata_async_notification - SATA async notification handler
981  *	@ap: ATA port where async notification is received
982  *
983  *	Handler to be called when async notification via SDB FIS is
984  *	received.  This function schedules EH if necessary.
985  *
986  *	LOCKING:
987  *	spin_lock_irqsave(host lock)
988  *
989  *	RETURNS:
990  *	1 if EH is scheduled, 0 otherwise.
991  */
992 int sata_async_notification(struct ata_port *ap)
993 {
994 	u32 sntf;
995 	int rc;
996 
997 	if (!(ap->flags & ATA_FLAG_AN))
998 		return 0;
999 
1000 	rc = sata_scr_read(&ap->link, SCR_NOTIFICATION, &sntf);
1001 	if (rc == 0)
1002 		sata_scr_write(&ap->link, SCR_NOTIFICATION, sntf);
1003 
1004 	if (!sata_pmp_attached(ap) || rc) {
1005 		/* PMP is not attached or SNTF is not available */
1006 		if (!sata_pmp_attached(ap)) {
1007 			/* PMP is not attached.  Check whether ATAPI
1008 			 * AN is configured.  If so, notify media
1009 			 * change.
1010 			 */
1011 			struct ata_device *dev = ap->link.device;
1012 
1013 			if ((dev->class == ATA_DEV_ATAPI) &&
1014 			    (dev->flags & ATA_DFLAG_AN))
1015 				ata_scsi_media_change_notify(dev);
1016 			return 0;
1017 		} else {
1018 			/* PMP is attached but SNTF is not available.
1019 			 * ATAPI async media change notification is
1020 			 * not used.  The PMP must be reporting PHY
1021 			 * status change, schedule EH.
1022 			 */
1023 			ata_port_schedule_eh(ap);
1024 			return 1;
1025 		}
1026 	} else {
1027 		/* PMP is attached and SNTF is available */
1028 		struct ata_link *link;
1029 
1030 		/* check and notify ATAPI AN */
1031 		ata_port_for_each_link(link, ap) {
1032 			if (!(sntf & (1 << link->pmp)))
1033 				continue;
1034 
1035 			if ((link->device->class == ATA_DEV_ATAPI) &&
1036 			    (link->device->flags & ATA_DFLAG_AN))
1037 				ata_scsi_media_change_notify(link->device);
1038 		}
1039 
1040 		/* If PMP is reporting that PHY status of some
1041 		 * downstream ports has changed, schedule EH.
1042 		 */
1043 		if (sntf & (1 << SATA_PMP_CTRL_PORT)) {
1044 			ata_port_schedule_eh(ap);
1045 			return 1;
1046 		}
1047 
1048 		return 0;
1049 	}
1050 }
1051 
1052 /**
1053  *	ata_eh_freeze_port - EH helper to freeze port
1054  *	@ap: ATA port to freeze
1055  *
1056  *	Freeze @ap.
1057  *
1058  *	LOCKING:
1059  *	None.
1060  */
1061 void ata_eh_freeze_port(struct ata_port *ap)
1062 {
1063 	unsigned long flags;
1064 
1065 	if (!ap->ops->error_handler)
1066 		return;
1067 
1068 	spin_lock_irqsave(ap->lock, flags);
1069 	__ata_port_freeze(ap);
1070 	spin_unlock_irqrestore(ap->lock, flags);
1071 }
1072 
1073 /**
1074  *	ata_port_thaw_port - EH helper to thaw port
1075  *	@ap: ATA port to thaw
1076  *
1077  *	Thaw frozen port @ap.
1078  *
1079  *	LOCKING:
1080  *	None.
1081  */
1082 void ata_eh_thaw_port(struct ata_port *ap)
1083 {
1084 	unsigned long flags;
1085 
1086 	if (!ap->ops->error_handler)
1087 		return;
1088 
1089 	spin_lock_irqsave(ap->lock, flags);
1090 
1091 	ap->pflags &= ~ATA_PFLAG_FROZEN;
1092 
1093 	if (ap->ops->thaw)
1094 		ap->ops->thaw(ap);
1095 
1096 	spin_unlock_irqrestore(ap->lock, flags);
1097 
1098 	DPRINTK("ata%u port thawed\n", ap->print_id);
1099 }
1100 
1101 static void ata_eh_scsidone(struct scsi_cmnd *scmd)
1102 {
1103 	/* nada */
1104 }
1105 
1106 static void __ata_eh_qc_complete(struct ata_queued_cmd *qc)
1107 {
1108 	struct ata_port *ap = qc->ap;
1109 	struct scsi_cmnd *scmd = qc->scsicmd;
1110 	unsigned long flags;
1111 
1112 	spin_lock_irqsave(ap->lock, flags);
1113 	qc->scsidone = ata_eh_scsidone;
1114 	__ata_qc_complete(qc);
1115 	WARN_ON(ata_tag_valid(qc->tag));
1116 	spin_unlock_irqrestore(ap->lock, flags);
1117 
1118 	scsi_eh_finish_cmd(scmd, &ap->eh_done_q);
1119 }
1120 
1121 /**
1122  *	ata_eh_qc_complete - Complete an active ATA command from EH
1123  *	@qc: Command to complete
1124  *
1125  *	Indicate to the mid and upper layers that an ATA command has
1126  *	completed.  To be used from EH.
1127  */
1128 void ata_eh_qc_complete(struct ata_queued_cmd *qc)
1129 {
1130 	struct scsi_cmnd *scmd = qc->scsicmd;
1131 	scmd->retries = scmd->allowed;
1132 	__ata_eh_qc_complete(qc);
1133 }
1134 
1135 /**
1136  *	ata_eh_qc_retry - Tell midlayer to retry an ATA command after EH
1137  *	@qc: Command to retry
1138  *
1139  *	Indicate to the mid and upper layers that an ATA command
1140  *	should be retried.  To be used from EH.
1141  *
1142  *	SCSI midlayer limits the number of retries to scmd->allowed.
1143  *	scmd->retries is decremented for commands which get retried
1144  *	due to unrelated failures (qc->err_mask is zero).
1145  */
1146 void ata_eh_qc_retry(struct ata_queued_cmd *qc)
1147 {
1148 	struct scsi_cmnd *scmd = qc->scsicmd;
1149 	if (!qc->err_mask && scmd->retries)
1150 		scmd->retries--;
1151 	__ata_eh_qc_complete(qc);
1152 }
1153 
1154 /**
1155  *	ata_eh_detach_dev - detach ATA device
1156  *	@dev: ATA device to detach
1157  *
1158  *	Detach @dev.
1159  *
1160  *	LOCKING:
1161  *	None.
1162  */
1163 void ata_eh_detach_dev(struct ata_device *dev)
1164 {
1165 	struct ata_link *link = dev->link;
1166 	struct ata_port *ap = link->ap;
1167 	struct ata_eh_context *ehc = &link->eh_context;
1168 	unsigned long flags;
1169 
1170 	ata_dev_disable(dev);
1171 
1172 	spin_lock_irqsave(ap->lock, flags);
1173 
1174 	dev->flags &= ~ATA_DFLAG_DETACH;
1175 
1176 	if (ata_scsi_offline_dev(dev)) {
1177 		dev->flags |= ATA_DFLAG_DETACHED;
1178 		ap->pflags |= ATA_PFLAG_SCSI_HOTPLUG;
1179 	}
1180 
1181 	/* clear per-dev EH info */
1182 	ata_eh_clear_action(link, dev, &link->eh_info, ATA_EH_PERDEV_MASK);
1183 	ata_eh_clear_action(link, dev, &link->eh_context.i, ATA_EH_PERDEV_MASK);
1184 	ehc->saved_xfer_mode[dev->devno] = 0;
1185 	ehc->saved_ncq_enabled &= ~(1 << dev->devno);
1186 
1187 	spin_unlock_irqrestore(ap->lock, flags);
1188 }
1189 
1190 /**
1191  *	ata_eh_about_to_do - about to perform eh_action
1192  *	@link: target ATA link
1193  *	@dev: target ATA dev for per-dev action (can be NULL)
1194  *	@action: action about to be performed
1195  *
1196  *	Called just before performing EH actions to clear related bits
1197  *	in @link->eh_info such that eh actions are not unnecessarily
1198  *	repeated.
1199  *
1200  *	LOCKING:
1201  *	None.
1202  */
1203 void ata_eh_about_to_do(struct ata_link *link, struct ata_device *dev,
1204 			unsigned int action)
1205 {
1206 	struct ata_port *ap = link->ap;
1207 	struct ata_eh_info *ehi = &link->eh_info;
1208 	struct ata_eh_context *ehc = &link->eh_context;
1209 	unsigned long flags;
1210 
1211 	spin_lock_irqsave(ap->lock, flags);
1212 
1213 	ata_eh_clear_action(link, dev, ehi, action);
1214 
1215 	/* About to take EH action, set RECOVERED.  Ignore actions on
1216 	 * slave links as master will do them again.
1217 	 */
1218 	if (!(ehc->i.flags & ATA_EHI_QUIET) && link != ap->slave_link)
1219 		ap->pflags |= ATA_PFLAG_RECOVERED;
1220 
1221 	spin_unlock_irqrestore(ap->lock, flags);
1222 }
1223 
1224 /**
1225  *	ata_eh_done - EH action complete
1226 *	@ap: target ATA port
1227  *	@dev: target ATA dev for per-dev action (can be NULL)
1228  *	@action: action just completed
1229  *
1230  *	Called right after performing EH actions to clear related bits
1231  *	in @link->eh_context.
1232  *
1233  *	LOCKING:
1234  *	None.
1235  */
1236 void ata_eh_done(struct ata_link *link, struct ata_device *dev,
1237 		 unsigned int action)
1238 {
1239 	struct ata_eh_context *ehc = &link->eh_context;
1240 
1241 	ata_eh_clear_action(link, dev, &ehc->i, action);
1242 }
1243 
1244 /**
1245  *	ata_err_string - convert err_mask to descriptive string
1246  *	@err_mask: error mask to convert to string
1247  *
1248  *	Convert @err_mask to descriptive string.  Errors are
1249  *	prioritized according to severity and only the most severe
1250  *	error is reported.
1251  *
1252  *	LOCKING:
1253  *	None.
1254  *
1255  *	RETURNS:
1256  *	Descriptive string for @err_mask
1257  */
1258 static const char *ata_err_string(unsigned int err_mask)
1259 {
1260 	if (err_mask & AC_ERR_HOST_BUS)
1261 		return "host bus error";
1262 	if (err_mask & AC_ERR_ATA_BUS)
1263 		return "ATA bus error";
1264 	if (err_mask & AC_ERR_TIMEOUT)
1265 		return "timeout";
1266 	if (err_mask & AC_ERR_HSM)
1267 		return "HSM violation";
1268 	if (err_mask & AC_ERR_SYSTEM)
1269 		return "internal error";
1270 	if (err_mask & AC_ERR_MEDIA)
1271 		return "media error";
1272 	if (err_mask & AC_ERR_INVALID)
1273 		return "invalid argument";
1274 	if (err_mask & AC_ERR_DEV)
1275 		return "device error";
1276 	return "unknown error";
1277 }
1278 
1279 /**
1280  *	ata_read_log_page - read a specific log page
1281  *	@dev: target device
1282  *	@page: page to read
1283  *	@buf: buffer to store read page
1284  *	@sectors: number of sectors to read
1285  *
1286  *	Read log page using READ_LOG_EXT command.
1287  *
1288  *	LOCKING:
1289  *	Kernel thread context (may sleep).
1290  *
1291  *	RETURNS:
1292  *	0 on success, AC_ERR_* mask otherwise.
1293  */
1294 static unsigned int ata_read_log_page(struct ata_device *dev,
1295 				      u8 page, void *buf, unsigned int sectors)
1296 {
1297 	struct ata_taskfile tf;
1298 	unsigned int err_mask;
1299 
1300 	DPRINTK("read log page - page %d\n", page);
1301 
1302 	ata_tf_init(dev, &tf);
1303 	tf.command = ATA_CMD_READ_LOG_EXT;
1304 	tf.lbal = page;
1305 	tf.nsect = sectors;
1306 	tf.hob_nsect = sectors >> 8;
1307 	tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_LBA48 | ATA_TFLAG_DEVICE;
1308 	tf.protocol = ATA_PROT_PIO;
1309 
1310 	err_mask = ata_exec_internal(dev, &tf, NULL, DMA_FROM_DEVICE,
1311 				     buf, sectors * ATA_SECT_SIZE, 0);
1312 
1313 	DPRINTK("EXIT, err_mask=%x\n", err_mask);
1314 	return err_mask;
1315 }
1316 
1317 /**
1318  *	ata_eh_read_log_10h - Read log page 10h for NCQ error details
1319  *	@dev: Device to read log page 10h from
1320  *	@tag: Resulting tag of the failed command
1321  *	@tf: Resulting taskfile registers of the failed command
1322  *
1323  *	Read log page 10h to obtain NCQ error details and clear error
1324  *	condition.
1325  *
1326  *	LOCKING:
1327  *	Kernel thread context (may sleep).
1328  *
1329  *	RETURNS:
1330  *	0 on success, -errno otherwise.
1331  */
1332 static int ata_eh_read_log_10h(struct ata_device *dev,
1333 			       int *tag, struct ata_taskfile *tf)
1334 {
1335 	u8 *buf = dev->link->ap->sector_buf;
1336 	unsigned int err_mask;
1337 	u8 csum;
1338 	int i;
1339 
1340 	err_mask = ata_read_log_page(dev, ATA_LOG_SATA_NCQ, buf, 1);
1341 	if (err_mask)
1342 		return -EIO;
1343 
1344 	csum = 0;
1345 	for (i = 0; i < ATA_SECT_SIZE; i++)
1346 		csum += buf[i];
1347 	if (csum)
1348 		ata_dev_printk(dev, KERN_WARNING,
1349 			       "invalid checksum 0x%x on log page 10h\n", csum);
1350 
1351 	if (buf[0] & 0x80)
1352 		return -ENOENT;
1353 
1354 	*tag = buf[0] & 0x1f;
1355 
1356 	tf->command = buf[2];
1357 	tf->feature = buf[3];
1358 	tf->lbal = buf[4];
1359 	tf->lbam = buf[5];
1360 	tf->lbah = buf[6];
1361 	tf->device = buf[7];
1362 	tf->hob_lbal = buf[8];
1363 	tf->hob_lbam = buf[9];
1364 	tf->hob_lbah = buf[10];
1365 	tf->nsect = buf[12];
1366 	tf->hob_nsect = buf[13];
1367 
1368 	return 0;
1369 }
1370 
1371 /**
1372  *	atapi_eh_tur - perform ATAPI TEST_UNIT_READY
1373  *	@dev: target ATAPI device
1374  *	@r_sense_key: out parameter for sense_key
1375  *
1376  *	Perform ATAPI TEST_UNIT_READY.
1377  *
1378  *	LOCKING:
1379  *	EH context (may sleep).
1380  *
1381  *	RETURNS:
1382  *	0 on success, AC_ERR_* mask on failure.
1383  */
1384 static unsigned int atapi_eh_tur(struct ata_device *dev, u8 *r_sense_key)
1385 {
1386 	u8 cdb[ATAPI_CDB_LEN] = { TEST_UNIT_READY, 0, 0, 0, 0, 0 };
1387 	struct ata_taskfile tf;
1388 	unsigned int err_mask;
1389 
1390 	ata_tf_init(dev, &tf);
1391 
1392 	tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
1393 	tf.command = ATA_CMD_PACKET;
1394 	tf.protocol = ATAPI_PROT_NODATA;
1395 
1396 	err_mask = ata_exec_internal(dev, &tf, cdb, DMA_NONE, NULL, 0, 0);
1397 	if (err_mask == AC_ERR_DEV)
1398 		*r_sense_key = tf.feature >> 4;
1399 	return err_mask;
1400 }
1401 
1402 /**
1403  *	atapi_eh_request_sense - perform ATAPI REQUEST_SENSE
1404  *	@dev: device to perform REQUEST_SENSE to
1405  *	@sense_buf: result sense data buffer (SCSI_SENSE_BUFFERSIZE bytes long)
1406  *	@dfl_sense_key: default sense key to use
1407  *
1408  *	Perform ATAPI REQUEST_SENSE after the device reported CHECK
1409  *	SENSE.  This function is EH helper.
1410  *
1411  *	LOCKING:
1412  *	Kernel thread context (may sleep).
1413  *
1414  *	RETURNS:
1415  *	0 on success, AC_ERR_* mask on failure
1416  */
1417 static unsigned int atapi_eh_request_sense(struct ata_device *dev,
1418 					   u8 *sense_buf, u8 dfl_sense_key)
1419 {
1420 	u8 cdb[ATAPI_CDB_LEN] =
1421 		{ REQUEST_SENSE, 0, 0, 0, SCSI_SENSE_BUFFERSIZE, 0 };
1422 	struct ata_port *ap = dev->link->ap;
1423 	struct ata_taskfile tf;
1424 
1425 	DPRINTK("ATAPI request sense\n");
1426 
1427 	/* FIXME: is this needed? */
1428 	memset(sense_buf, 0, SCSI_SENSE_BUFFERSIZE);
1429 
1430 	/* initialize sense_buf with the error register,
1431 	 * for the case where they are -not- overwritten
1432 	 */
1433 	sense_buf[0] = 0x70;
1434 	sense_buf[2] = dfl_sense_key;
1435 
1436 	/* some devices time out if garbage left in tf */
1437 	ata_tf_init(dev, &tf);
1438 
1439 	tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
1440 	tf.command = ATA_CMD_PACKET;
1441 
1442 	/* is it pointless to prefer PIO for "safety reasons"? */
1443 	if (ap->flags & ATA_FLAG_PIO_DMA) {
1444 		tf.protocol = ATAPI_PROT_DMA;
1445 		tf.feature |= ATAPI_PKT_DMA;
1446 	} else {
1447 		tf.protocol = ATAPI_PROT_PIO;
1448 		tf.lbam = SCSI_SENSE_BUFFERSIZE;
1449 		tf.lbah = 0;
1450 	}
1451 
1452 	return ata_exec_internal(dev, &tf, cdb, DMA_FROM_DEVICE,
1453 				 sense_buf, SCSI_SENSE_BUFFERSIZE, 0);
1454 }
1455 
1456 /**
1457  *	ata_eh_analyze_serror - analyze SError for a failed port
1458  *	@link: ATA link to analyze SError for
1459  *
1460  *	Analyze SError if available and further determine cause of
1461  *	failure.
1462  *
1463  *	LOCKING:
1464  *	None.
1465  */
1466 static void ata_eh_analyze_serror(struct ata_link *link)
1467 {
1468 	struct ata_eh_context *ehc = &link->eh_context;
1469 	u32 serror = ehc->i.serror;
1470 	unsigned int err_mask = 0, action = 0;
1471 	u32 hotplug_mask;
1472 
1473 	if (serror & (SERR_PERSISTENT | SERR_DATA)) {
1474 		err_mask |= AC_ERR_ATA_BUS;
1475 		action |= ATA_EH_RESET;
1476 	}
1477 	if (serror & SERR_PROTOCOL) {
1478 		err_mask |= AC_ERR_HSM;
1479 		action |= ATA_EH_RESET;
1480 	}
1481 	if (serror & SERR_INTERNAL) {
1482 		err_mask |= AC_ERR_SYSTEM;
1483 		action |= ATA_EH_RESET;
1484 	}
1485 
1486 	/* Determine whether a hotplug event has occurred.  Both
1487 	 * SError.N/X are considered hotplug events for enabled or
1488 	 * host links.  For disabled PMP links, only N bit is
1489 	 * considered as X bit is left at 1 for link plugging.
1490 	 */
1491 	hotplug_mask = 0;
1492 
1493 	if (!(link->flags & ATA_LFLAG_DISABLED) || ata_is_host_link(link))
1494 		hotplug_mask = SERR_PHYRDY_CHG | SERR_DEV_XCHG;
1495 	else
1496 		hotplug_mask = SERR_PHYRDY_CHG;
1497 
1498 	if (serror & hotplug_mask)
1499 		ata_ehi_hotplugged(&ehc->i);
1500 
1501 	ehc->i.err_mask |= err_mask;
1502 	ehc->i.action |= action;
1503 }
1504 
1505 /**
1506  *	ata_eh_analyze_ncq_error - analyze NCQ error
1507  *	@link: ATA link to analyze NCQ error for
1508  *
1509  *	Read log page 10h, determine the offending qc and acquire
1510  *	error status TF.  For NCQ device errors, all LLDDs have to do
1511  *	is setting AC_ERR_DEV in ehi->err_mask.  This function takes
1512  *	care of the rest.
1513  *
1514  *	LOCKING:
1515  *	Kernel thread context (may sleep).
1516  */
1517 void ata_eh_analyze_ncq_error(struct ata_link *link)
1518 {
1519 	struct ata_port *ap = link->ap;
1520 	struct ata_eh_context *ehc = &link->eh_context;
1521 	struct ata_device *dev = link->device;
1522 	struct ata_queued_cmd *qc;
1523 	struct ata_taskfile tf;
1524 	int tag, rc;
1525 
1526 	/* if frozen, we can't do much */
1527 	if (ap->pflags & ATA_PFLAG_FROZEN)
1528 		return;
1529 
1530 	/* is it NCQ device error? */
1531 	if (!link->sactive || !(ehc->i.err_mask & AC_ERR_DEV))
1532 		return;
1533 
1534 	/* has LLDD analyzed already? */
1535 	for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
1536 		qc = __ata_qc_from_tag(ap, tag);
1537 
1538 		if (!(qc->flags & ATA_QCFLAG_FAILED))
1539 			continue;
1540 
1541 		if (qc->err_mask)
1542 			return;
1543 	}
1544 
1545 	/* okay, this error is ours */
1546 	rc = ata_eh_read_log_10h(dev, &tag, &tf);
1547 	if (rc) {
1548 		ata_link_printk(link, KERN_ERR, "failed to read log page 10h "
1549 				"(errno=%d)\n", rc);
1550 		return;
1551 	}
1552 
1553 	if (!(link->sactive & (1 << tag))) {
1554 		ata_link_printk(link, KERN_ERR, "log page 10h reported "
1555 				"inactive tag %d\n", tag);
1556 		return;
1557 	}
1558 
1559 	/* we've got the perpetrator, condemn it */
1560 	qc = __ata_qc_from_tag(ap, tag);
1561 	memcpy(&qc->result_tf, &tf, sizeof(tf));
1562 	qc->result_tf.flags = ATA_TFLAG_ISADDR | ATA_TFLAG_LBA | ATA_TFLAG_LBA48;
1563 	qc->err_mask |= AC_ERR_DEV | AC_ERR_NCQ;
1564 	ehc->i.err_mask &= ~AC_ERR_DEV;
1565 }
1566 
1567 /**
1568  *	ata_eh_analyze_tf - analyze taskfile of a failed qc
1569  *	@qc: qc to analyze
1570  *	@tf: Taskfile registers to analyze
1571  *
1572  *	Analyze taskfile of @qc and further determine cause of
1573  *	failure.  This function also requests ATAPI sense data if
1574  *	avaliable.
1575  *
1576  *	LOCKING:
1577  *	Kernel thread context (may sleep).
1578  *
1579  *	RETURNS:
1580  *	Determined recovery action
1581  */
1582 static unsigned int ata_eh_analyze_tf(struct ata_queued_cmd *qc,
1583 				      const struct ata_taskfile *tf)
1584 {
1585 	unsigned int tmp, action = 0;
1586 	u8 stat = tf->command, err = tf->feature;
1587 
1588 	if ((stat & (ATA_BUSY | ATA_DRQ | ATA_DRDY)) != ATA_DRDY) {
1589 		qc->err_mask |= AC_ERR_HSM;
1590 		return ATA_EH_RESET;
1591 	}
1592 
1593 	if (stat & (ATA_ERR | ATA_DF))
1594 		qc->err_mask |= AC_ERR_DEV;
1595 	else
1596 		return 0;
1597 
1598 	switch (qc->dev->class) {
1599 	case ATA_DEV_ATA:
1600 		if (err & ATA_ICRC)
1601 			qc->err_mask |= AC_ERR_ATA_BUS;
1602 		if (err & ATA_UNC)
1603 			qc->err_mask |= AC_ERR_MEDIA;
1604 		if (err & ATA_IDNF)
1605 			qc->err_mask |= AC_ERR_INVALID;
1606 		break;
1607 
1608 	case ATA_DEV_ATAPI:
1609 		if (!(qc->ap->pflags & ATA_PFLAG_FROZEN)) {
1610 			tmp = atapi_eh_request_sense(qc->dev,
1611 						qc->scsicmd->sense_buffer,
1612 						qc->result_tf.feature >> 4);
1613 			if (!tmp) {
1614 				/* ATA_QCFLAG_SENSE_VALID is used to
1615 				 * tell atapi_qc_complete() that sense
1616 				 * data is already valid.
1617 				 *
1618 				 * TODO: interpret sense data and set
1619 				 * appropriate err_mask.
1620 				 */
1621 				qc->flags |= ATA_QCFLAG_SENSE_VALID;
1622 			} else
1623 				qc->err_mask |= tmp;
1624 		}
1625 	}
1626 
1627 	if (qc->err_mask & (AC_ERR_HSM | AC_ERR_TIMEOUT | AC_ERR_ATA_BUS))
1628 		action |= ATA_EH_RESET;
1629 
1630 	return action;
1631 }
1632 
1633 static int ata_eh_categorize_error(unsigned int eflags, unsigned int err_mask,
1634 				   int *xfer_ok)
1635 {
1636 	int base = 0;
1637 
1638 	if (!(eflags & ATA_EFLAG_DUBIOUS_XFER))
1639 		*xfer_ok = 1;
1640 
1641 	if (!*xfer_ok)
1642 		base = ATA_ECAT_DUBIOUS_NONE;
1643 
1644 	if (err_mask & AC_ERR_ATA_BUS)
1645 		return base + ATA_ECAT_ATA_BUS;
1646 
1647 	if (err_mask & AC_ERR_TIMEOUT)
1648 		return base + ATA_ECAT_TOUT_HSM;
1649 
1650 	if (eflags & ATA_EFLAG_IS_IO) {
1651 		if (err_mask & AC_ERR_HSM)
1652 			return base + ATA_ECAT_TOUT_HSM;
1653 		if ((err_mask &
1654 		     (AC_ERR_DEV|AC_ERR_MEDIA|AC_ERR_INVALID)) == AC_ERR_DEV)
1655 			return base + ATA_ECAT_UNK_DEV;
1656 	}
1657 
1658 	return 0;
1659 }
1660 
1661 struct speed_down_verdict_arg {
1662 	u64 since;
1663 	int xfer_ok;
1664 	int nr_errors[ATA_ECAT_NR];
1665 };
1666 
1667 static int speed_down_verdict_cb(struct ata_ering_entry *ent, void *void_arg)
1668 {
1669 	struct speed_down_verdict_arg *arg = void_arg;
1670 	int cat;
1671 
1672 	if (ent->timestamp < arg->since)
1673 		return -1;
1674 
1675 	cat = ata_eh_categorize_error(ent->eflags, ent->err_mask,
1676 				      &arg->xfer_ok);
1677 	arg->nr_errors[cat]++;
1678 
1679 	return 0;
1680 }
1681 
1682 /**
1683  *	ata_eh_speed_down_verdict - Determine speed down verdict
1684  *	@dev: Device of interest
1685  *
1686  *	This function examines error ring of @dev and determines
1687  *	whether NCQ needs to be turned off, transfer speed should be
1688  *	stepped down, or falling back to PIO is necessary.
1689  *
1690  *	ECAT_ATA_BUS	: ATA_BUS error for any command
1691  *
1692  *	ECAT_TOUT_HSM	: TIMEOUT for any command or HSM violation for
1693  *			  IO commands
1694  *
1695  *	ECAT_UNK_DEV	: Unknown DEV error for IO commands
1696  *
1697  *	ECAT_DUBIOUS_*	: Identical to above three but occurred while
1698  *			  data transfer hasn't been verified.
1699  *
1700  *	Verdicts are
1701  *
1702  *	NCQ_OFF		: Turn off NCQ.
1703  *
1704  *	SPEED_DOWN	: Speed down transfer speed but don't fall back
1705  *			  to PIO.
1706  *
1707  *	FALLBACK_TO_PIO	: Fall back to PIO.
1708  *
1709  *	Even if multiple verdicts are returned, only one action is
1710  *	taken per error.  An action triggered by non-DUBIOUS errors
1711  *	clears ering, while one triggered by DUBIOUS_* errors doesn't.
1712  *	This is to expedite speed down decisions right after device is
1713  *	initially configured.
1714  *
1715  *	The followings are speed down rules.  #1 and #2 deal with
1716  *	DUBIOUS errors.
1717  *
1718  *	1. If more than one DUBIOUS_ATA_BUS or DUBIOUS_TOUT_HSM errors
1719  *	   occurred during last 5 mins, SPEED_DOWN and FALLBACK_TO_PIO.
1720  *
1721  *	2. If more than one DUBIOUS_TOUT_HSM or DUBIOUS_UNK_DEV errors
1722  *	   occurred during last 5 mins, NCQ_OFF.
1723  *
1724  *	3. If more than 8 ATA_BUS, TOUT_HSM or UNK_DEV errors
1725  *	   ocurred during last 5 mins, FALLBACK_TO_PIO
1726  *
1727  *	4. If more than 3 TOUT_HSM or UNK_DEV errors occurred
1728  *	   during last 10 mins, NCQ_OFF.
1729  *
1730  *	5. If more than 3 ATA_BUS or TOUT_HSM errors, or more than 6
1731  *	   UNK_DEV errors occurred during last 10 mins, SPEED_DOWN.
1732  *
1733  *	LOCKING:
1734  *	Inherited from caller.
1735  *
1736  *	RETURNS:
1737  *	OR of ATA_EH_SPDN_* flags.
1738  */
1739 static unsigned int ata_eh_speed_down_verdict(struct ata_device *dev)
1740 {
1741 	const u64 j5mins = 5LLU * 60 * HZ, j10mins = 10LLU * 60 * HZ;
1742 	u64 j64 = get_jiffies_64();
1743 	struct speed_down_verdict_arg arg;
1744 	unsigned int verdict = 0;
1745 
1746 	/* scan past 5 mins of error history */
1747 	memset(&arg, 0, sizeof(arg));
1748 	arg.since = j64 - min(j64, j5mins);
1749 	ata_ering_map(&dev->ering, speed_down_verdict_cb, &arg);
1750 
1751 	if (arg.nr_errors[ATA_ECAT_DUBIOUS_ATA_BUS] +
1752 	    arg.nr_errors[ATA_ECAT_DUBIOUS_TOUT_HSM] > 1)
1753 		verdict |= ATA_EH_SPDN_SPEED_DOWN |
1754 			ATA_EH_SPDN_FALLBACK_TO_PIO | ATA_EH_SPDN_KEEP_ERRORS;
1755 
1756 	if (arg.nr_errors[ATA_ECAT_DUBIOUS_TOUT_HSM] +
1757 	    arg.nr_errors[ATA_ECAT_DUBIOUS_UNK_DEV] > 1)
1758 		verdict |= ATA_EH_SPDN_NCQ_OFF | ATA_EH_SPDN_KEEP_ERRORS;
1759 
1760 	if (arg.nr_errors[ATA_ECAT_ATA_BUS] +
1761 	    arg.nr_errors[ATA_ECAT_TOUT_HSM] +
1762 	    arg.nr_errors[ATA_ECAT_UNK_DEV] > 6)
1763 		verdict |= ATA_EH_SPDN_FALLBACK_TO_PIO;
1764 
1765 	/* scan past 10 mins of error history */
1766 	memset(&arg, 0, sizeof(arg));
1767 	arg.since = j64 - min(j64, j10mins);
1768 	ata_ering_map(&dev->ering, speed_down_verdict_cb, &arg);
1769 
1770 	if (arg.nr_errors[ATA_ECAT_TOUT_HSM] +
1771 	    arg.nr_errors[ATA_ECAT_UNK_DEV] > 3)
1772 		verdict |= ATA_EH_SPDN_NCQ_OFF;
1773 
1774 	if (arg.nr_errors[ATA_ECAT_ATA_BUS] +
1775 	    arg.nr_errors[ATA_ECAT_TOUT_HSM] > 3 ||
1776 	    arg.nr_errors[ATA_ECAT_UNK_DEV] > 6)
1777 		verdict |= ATA_EH_SPDN_SPEED_DOWN;
1778 
1779 	return verdict;
1780 }
1781 
1782 /**
1783  *	ata_eh_speed_down - record error and speed down if necessary
1784  *	@dev: Failed device
1785  *	@eflags: mask of ATA_EFLAG_* flags
1786  *	@err_mask: err_mask of the error
1787  *
1788  *	Record error and examine error history to determine whether
1789  *	adjusting transmission speed is necessary.  It also sets
1790  *	transmission limits appropriately if such adjustment is
1791  *	necessary.
1792  *
1793  *	LOCKING:
1794  *	Kernel thread context (may sleep).
1795  *
1796  *	RETURNS:
1797  *	Determined recovery action.
1798  */
1799 static unsigned int ata_eh_speed_down(struct ata_device *dev,
1800 				unsigned int eflags, unsigned int err_mask)
1801 {
1802 	struct ata_link *link = ata_dev_phys_link(dev);
1803 	int xfer_ok = 0;
1804 	unsigned int verdict;
1805 	unsigned int action = 0;
1806 
1807 	/* don't bother if Cat-0 error */
1808 	if (ata_eh_categorize_error(eflags, err_mask, &xfer_ok) == 0)
1809 		return 0;
1810 
1811 	/* record error and determine whether speed down is necessary */
1812 	ata_ering_record(&dev->ering, eflags, err_mask);
1813 	verdict = ata_eh_speed_down_verdict(dev);
1814 
1815 	/* turn off NCQ? */
1816 	if ((verdict & ATA_EH_SPDN_NCQ_OFF) &&
1817 	    (dev->flags & (ATA_DFLAG_PIO | ATA_DFLAG_NCQ |
1818 			   ATA_DFLAG_NCQ_OFF)) == ATA_DFLAG_NCQ) {
1819 		dev->flags |= ATA_DFLAG_NCQ_OFF;
1820 		ata_dev_printk(dev, KERN_WARNING,
1821 			       "NCQ disabled due to excessive errors\n");
1822 		goto done;
1823 	}
1824 
1825 	/* speed down? */
1826 	if (verdict & ATA_EH_SPDN_SPEED_DOWN) {
1827 		/* speed down SATA link speed if possible */
1828 		if (sata_down_spd_limit(link) == 0) {
1829 			action |= ATA_EH_RESET;
1830 			goto done;
1831 		}
1832 
1833 		/* lower transfer mode */
1834 		if (dev->spdn_cnt < 2) {
1835 			static const int dma_dnxfer_sel[] =
1836 				{ ATA_DNXFER_DMA, ATA_DNXFER_40C };
1837 			static const int pio_dnxfer_sel[] =
1838 				{ ATA_DNXFER_PIO, ATA_DNXFER_FORCE_PIO0 };
1839 			int sel;
1840 
1841 			if (dev->xfer_shift != ATA_SHIFT_PIO)
1842 				sel = dma_dnxfer_sel[dev->spdn_cnt];
1843 			else
1844 				sel = pio_dnxfer_sel[dev->spdn_cnt];
1845 
1846 			dev->spdn_cnt++;
1847 
1848 			if (ata_down_xfermask_limit(dev, sel) == 0) {
1849 				action |= ATA_EH_RESET;
1850 				goto done;
1851 			}
1852 		}
1853 	}
1854 
1855 	/* Fall back to PIO?  Slowing down to PIO is meaningless for
1856 	 * SATA ATA devices.  Consider it only for PATA and SATAPI.
1857 	 */
1858 	if ((verdict & ATA_EH_SPDN_FALLBACK_TO_PIO) && (dev->spdn_cnt >= 2) &&
1859 	    (link->ap->cbl != ATA_CBL_SATA || dev->class == ATA_DEV_ATAPI) &&
1860 	    (dev->xfer_shift != ATA_SHIFT_PIO)) {
1861 		if (ata_down_xfermask_limit(dev, ATA_DNXFER_FORCE_PIO) == 0) {
1862 			dev->spdn_cnt = 0;
1863 			action |= ATA_EH_RESET;
1864 			goto done;
1865 		}
1866 	}
1867 
1868 	return 0;
1869  done:
1870 	/* device has been slowed down, blow error history */
1871 	if (!(verdict & ATA_EH_SPDN_KEEP_ERRORS))
1872 		ata_ering_clear(&dev->ering);
1873 	return action;
1874 }
1875 
1876 /**
1877  *	ata_eh_link_autopsy - analyze error and determine recovery action
1878  *	@link: host link to perform autopsy on
1879  *
1880  *	Analyze why @link failed and determine which recovery actions
1881  *	are needed.  This function also sets more detailed AC_ERR_*
1882  *	values and fills sense data for ATAPI CHECK SENSE.
1883  *
1884  *	LOCKING:
1885  *	Kernel thread context (may sleep).
1886  */
1887 static void ata_eh_link_autopsy(struct ata_link *link)
1888 {
1889 	struct ata_port *ap = link->ap;
1890 	struct ata_eh_context *ehc = &link->eh_context;
1891 	struct ata_device *dev;
1892 	unsigned int all_err_mask = 0, eflags = 0;
1893 	int tag;
1894 	u32 serror;
1895 	int rc;
1896 
1897 	DPRINTK("ENTER\n");
1898 
1899 	if (ehc->i.flags & ATA_EHI_NO_AUTOPSY)
1900 		return;
1901 
1902 	/* obtain and analyze SError */
1903 	rc = sata_scr_read(link, SCR_ERROR, &serror);
1904 	if (rc == 0) {
1905 		ehc->i.serror |= serror;
1906 		ata_eh_analyze_serror(link);
1907 	} else if (rc != -EOPNOTSUPP) {
1908 		/* SError read failed, force reset and probing */
1909 		ehc->i.probe_mask |= ATA_ALL_DEVICES;
1910 		ehc->i.action |= ATA_EH_RESET;
1911 		ehc->i.err_mask |= AC_ERR_OTHER;
1912 	}
1913 
1914 	/* analyze NCQ failure */
1915 	ata_eh_analyze_ncq_error(link);
1916 
1917 	/* any real error trumps AC_ERR_OTHER */
1918 	if (ehc->i.err_mask & ~AC_ERR_OTHER)
1919 		ehc->i.err_mask &= ~AC_ERR_OTHER;
1920 
1921 	all_err_mask |= ehc->i.err_mask;
1922 
1923 	for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
1924 		struct ata_queued_cmd *qc = __ata_qc_from_tag(ap, tag);
1925 
1926 		if (!(qc->flags & ATA_QCFLAG_FAILED) ||
1927 		    ata_dev_phys_link(qc->dev) != link)
1928 			continue;
1929 
1930 		/* inherit upper level err_mask */
1931 		qc->err_mask |= ehc->i.err_mask;
1932 
1933 		/* analyze TF */
1934 		ehc->i.action |= ata_eh_analyze_tf(qc, &qc->result_tf);
1935 
1936 		/* DEV errors are probably spurious in case of ATA_BUS error */
1937 		if (qc->err_mask & AC_ERR_ATA_BUS)
1938 			qc->err_mask &= ~(AC_ERR_DEV | AC_ERR_MEDIA |
1939 					  AC_ERR_INVALID);
1940 
1941 		/* any real error trumps unknown error */
1942 		if (qc->err_mask & ~AC_ERR_OTHER)
1943 			qc->err_mask &= ~AC_ERR_OTHER;
1944 
1945 		/* SENSE_VALID trumps dev/unknown error and revalidation */
1946 		if (qc->flags & ATA_QCFLAG_SENSE_VALID)
1947 			qc->err_mask &= ~(AC_ERR_DEV | AC_ERR_OTHER);
1948 
1949 		/* determine whether the command is worth retrying */
1950 		if (!(qc->err_mask & AC_ERR_INVALID) &&
1951 		    ((qc->flags & ATA_QCFLAG_IO) || qc->err_mask != AC_ERR_DEV))
1952 			qc->flags |= ATA_QCFLAG_RETRY;
1953 
1954 		/* accumulate error info */
1955 		ehc->i.dev = qc->dev;
1956 		all_err_mask |= qc->err_mask;
1957 		if (qc->flags & ATA_QCFLAG_IO)
1958 			eflags |= ATA_EFLAG_IS_IO;
1959 	}
1960 
1961 	/* enforce default EH actions */
1962 	if (ap->pflags & ATA_PFLAG_FROZEN ||
1963 	    all_err_mask & (AC_ERR_HSM | AC_ERR_TIMEOUT))
1964 		ehc->i.action |= ATA_EH_RESET;
1965 	else if (((eflags & ATA_EFLAG_IS_IO) && all_err_mask) ||
1966 		 (!(eflags & ATA_EFLAG_IS_IO) && (all_err_mask & ~AC_ERR_DEV)))
1967 		ehc->i.action |= ATA_EH_REVALIDATE;
1968 
1969 	/* If we have offending qcs and the associated failed device,
1970 	 * perform per-dev EH action only on the offending device.
1971 	 */
1972 	if (ehc->i.dev) {
1973 		ehc->i.dev_action[ehc->i.dev->devno] |=
1974 			ehc->i.action & ATA_EH_PERDEV_MASK;
1975 		ehc->i.action &= ~ATA_EH_PERDEV_MASK;
1976 	}
1977 
1978 	/* propagate timeout to host link */
1979 	if ((all_err_mask & AC_ERR_TIMEOUT) && !ata_is_host_link(link))
1980 		ap->link.eh_context.i.err_mask |= AC_ERR_TIMEOUT;
1981 
1982 	/* record error and consider speeding down */
1983 	dev = ehc->i.dev;
1984 	if (!dev && ((ata_link_max_devices(link) == 1 &&
1985 		      ata_dev_enabled(link->device))))
1986 	    dev = link->device;
1987 
1988 	if (dev) {
1989 		if (dev->flags & ATA_DFLAG_DUBIOUS_XFER)
1990 			eflags |= ATA_EFLAG_DUBIOUS_XFER;
1991 		ehc->i.action |= ata_eh_speed_down(dev, eflags, all_err_mask);
1992 	}
1993 
1994 	DPRINTK("EXIT\n");
1995 }
1996 
1997 /**
1998  *	ata_eh_autopsy - analyze error and determine recovery action
1999  *	@ap: host port to perform autopsy on
2000  *
2001  *	Analyze all links of @ap and determine why they failed and
2002  *	which recovery actions are needed.
2003  *
2004  *	LOCKING:
2005  *	Kernel thread context (may sleep).
2006  */
2007 void ata_eh_autopsy(struct ata_port *ap)
2008 {
2009 	struct ata_link *link;
2010 
2011 	ata_port_for_each_link(link, ap)
2012 		ata_eh_link_autopsy(link);
2013 
2014 	/* Handle the frigging slave link.  Autopsy is done similarly
2015 	 * but actions and flags are transferred over to the master
2016 	 * link and handled from there.
2017 	 */
2018 	if (ap->slave_link) {
2019 		struct ata_eh_context *mehc = &ap->link.eh_context;
2020 		struct ata_eh_context *sehc = &ap->slave_link->eh_context;
2021 
2022 		/* transfer control flags from master to slave */
2023 		sehc->i.flags |= mehc->i.flags & ATA_EHI_TO_SLAVE_MASK;
2024 
2025 		/* perform autopsy on the slave link */
2026 		ata_eh_link_autopsy(ap->slave_link);
2027 
2028 		/* transfer actions from slave to master and clear slave */
2029 		ata_eh_about_to_do(ap->slave_link, NULL, ATA_EH_ALL_ACTIONS);
2030 		mehc->i.action		|= sehc->i.action;
2031 		mehc->i.dev_action[1]	|= sehc->i.dev_action[1];
2032 		mehc->i.flags		|= sehc->i.flags;
2033 		ata_eh_done(ap->slave_link, NULL, ATA_EH_ALL_ACTIONS);
2034 	}
2035 
2036 	/* Autopsy of fanout ports can affect host link autopsy.
2037 	 * Perform host link autopsy last.
2038 	 */
2039 	if (sata_pmp_attached(ap))
2040 		ata_eh_link_autopsy(&ap->link);
2041 }
2042 
2043 /**
2044  *	ata_eh_link_report - report error handling to user
2045  *	@link: ATA link EH is going on
2046  *
2047  *	Report EH to user.
2048  *
2049  *	LOCKING:
2050  *	None.
2051  */
2052 static void ata_eh_link_report(struct ata_link *link)
2053 {
2054 	struct ata_port *ap = link->ap;
2055 	struct ata_eh_context *ehc = &link->eh_context;
2056 	const char *frozen, *desc;
2057 	char tries_buf[6];
2058 	int tag, nr_failed = 0;
2059 
2060 	if (ehc->i.flags & ATA_EHI_QUIET)
2061 		return;
2062 
2063 	desc = NULL;
2064 	if (ehc->i.desc[0] != '\0')
2065 		desc = ehc->i.desc;
2066 
2067 	for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
2068 		struct ata_queued_cmd *qc = __ata_qc_from_tag(ap, tag);
2069 
2070 		if (!(qc->flags & ATA_QCFLAG_FAILED) ||
2071 		    ata_dev_phys_link(qc->dev) != link ||
2072 		    ((qc->flags & ATA_QCFLAG_QUIET) &&
2073 		     qc->err_mask == AC_ERR_DEV))
2074 			continue;
2075 		if (qc->flags & ATA_QCFLAG_SENSE_VALID && !qc->err_mask)
2076 			continue;
2077 
2078 		nr_failed++;
2079 	}
2080 
2081 	if (!nr_failed && !ehc->i.err_mask)
2082 		return;
2083 
2084 	frozen = "";
2085 	if (ap->pflags & ATA_PFLAG_FROZEN)
2086 		frozen = " frozen";
2087 
2088 	memset(tries_buf, 0, sizeof(tries_buf));
2089 	if (ap->eh_tries < ATA_EH_MAX_TRIES)
2090 		snprintf(tries_buf, sizeof(tries_buf) - 1, " t%d",
2091 			 ap->eh_tries);
2092 
2093 	if (ehc->i.dev) {
2094 		ata_dev_printk(ehc->i.dev, KERN_ERR, "exception Emask 0x%x "
2095 			       "SAct 0x%x SErr 0x%x action 0x%x%s%s\n",
2096 			       ehc->i.err_mask, link->sactive, ehc->i.serror,
2097 			       ehc->i.action, frozen, tries_buf);
2098 		if (desc)
2099 			ata_dev_printk(ehc->i.dev, KERN_ERR, "%s\n", desc);
2100 	} else {
2101 		ata_link_printk(link, KERN_ERR, "exception Emask 0x%x "
2102 				"SAct 0x%x SErr 0x%x action 0x%x%s%s\n",
2103 				ehc->i.err_mask, link->sactive, ehc->i.serror,
2104 				ehc->i.action, frozen, tries_buf);
2105 		if (desc)
2106 			ata_link_printk(link, KERN_ERR, "%s\n", desc);
2107 	}
2108 
2109 	if (ehc->i.serror)
2110 		ata_link_printk(link, KERN_ERR,
2111 		  "SError: { %s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s}\n",
2112 		  ehc->i.serror & SERR_DATA_RECOVERED ? "RecovData " : "",
2113 		  ehc->i.serror & SERR_COMM_RECOVERED ? "RecovComm " : "",
2114 		  ehc->i.serror & SERR_DATA ? "UnrecovData " : "",
2115 		  ehc->i.serror & SERR_PERSISTENT ? "Persist " : "",
2116 		  ehc->i.serror & SERR_PROTOCOL ? "Proto " : "",
2117 		  ehc->i.serror & SERR_INTERNAL ? "HostInt " : "",
2118 		  ehc->i.serror & SERR_PHYRDY_CHG ? "PHYRdyChg " : "",
2119 		  ehc->i.serror & SERR_PHY_INT_ERR ? "PHYInt " : "",
2120 		  ehc->i.serror & SERR_COMM_WAKE ? "CommWake " : "",
2121 		  ehc->i.serror & SERR_10B_8B_ERR ? "10B8B " : "",
2122 		  ehc->i.serror & SERR_DISPARITY ? "Dispar " : "",
2123 		  ehc->i.serror & SERR_CRC ? "BadCRC " : "",
2124 		  ehc->i.serror & SERR_HANDSHAKE ? "Handshk " : "",
2125 		  ehc->i.serror & SERR_LINK_SEQ_ERR ? "LinkSeq " : "",
2126 		  ehc->i.serror & SERR_TRANS_ST_ERROR ? "TrStaTrns " : "",
2127 		  ehc->i.serror & SERR_UNRECOG_FIS ? "UnrecFIS " : "",
2128 		  ehc->i.serror & SERR_DEV_XCHG ? "DevExch " : "");
2129 
2130 	for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
2131 		struct ata_queued_cmd *qc = __ata_qc_from_tag(ap, tag);
2132 		struct ata_taskfile *cmd = &qc->tf, *res = &qc->result_tf;
2133 		const u8 *cdb = qc->cdb;
2134 		char data_buf[20] = "";
2135 		char cdb_buf[70] = "";
2136 
2137 		if (!(qc->flags & ATA_QCFLAG_FAILED) ||
2138 		    ata_dev_phys_link(qc->dev) != link || !qc->err_mask)
2139 			continue;
2140 
2141 		if (qc->dma_dir != DMA_NONE) {
2142 			static const char *dma_str[] = {
2143 				[DMA_BIDIRECTIONAL]	= "bidi",
2144 				[DMA_TO_DEVICE]		= "out",
2145 				[DMA_FROM_DEVICE]	= "in",
2146 			};
2147 			static const char *prot_str[] = {
2148 				[ATA_PROT_PIO]		= "pio",
2149 				[ATA_PROT_DMA]		= "dma",
2150 				[ATA_PROT_NCQ]		= "ncq",
2151 				[ATAPI_PROT_PIO]	= "pio",
2152 				[ATAPI_PROT_DMA]	= "dma",
2153 			};
2154 
2155 			snprintf(data_buf, sizeof(data_buf), " %s %u %s",
2156 				 prot_str[qc->tf.protocol], qc->nbytes,
2157 				 dma_str[qc->dma_dir]);
2158 		}
2159 
2160 		if (ata_is_atapi(qc->tf.protocol))
2161 			snprintf(cdb_buf, sizeof(cdb_buf),
2162 				 "cdb %02x %02x %02x %02x %02x %02x %02x %02x  "
2163 				 "%02x %02x %02x %02x %02x %02x %02x %02x\n         ",
2164 				 cdb[0], cdb[1], cdb[2], cdb[3],
2165 				 cdb[4], cdb[5], cdb[6], cdb[7],
2166 				 cdb[8], cdb[9], cdb[10], cdb[11],
2167 				 cdb[12], cdb[13], cdb[14], cdb[15]);
2168 
2169 		ata_dev_printk(qc->dev, KERN_ERR,
2170 			"cmd %02x/%02x:%02x:%02x:%02x:%02x/%02x:%02x:%02x:%02x:%02x/%02x "
2171 			"tag %d%s\n         %s"
2172 			"res %02x/%02x:%02x:%02x:%02x:%02x/%02x:%02x:%02x:%02x:%02x/%02x "
2173 			"Emask 0x%x (%s)%s\n",
2174 			cmd->command, cmd->feature, cmd->nsect,
2175 			cmd->lbal, cmd->lbam, cmd->lbah,
2176 			cmd->hob_feature, cmd->hob_nsect,
2177 			cmd->hob_lbal, cmd->hob_lbam, cmd->hob_lbah,
2178 			cmd->device, qc->tag, data_buf, cdb_buf,
2179 			res->command, res->feature, res->nsect,
2180 			res->lbal, res->lbam, res->lbah,
2181 			res->hob_feature, res->hob_nsect,
2182 			res->hob_lbal, res->hob_lbam, res->hob_lbah,
2183 			res->device, qc->err_mask, ata_err_string(qc->err_mask),
2184 			qc->err_mask & AC_ERR_NCQ ? " <F>" : "");
2185 
2186 		if (res->command & (ATA_BUSY | ATA_DRDY | ATA_DF | ATA_DRQ |
2187 				    ATA_ERR)) {
2188 			if (res->command & ATA_BUSY)
2189 				ata_dev_printk(qc->dev, KERN_ERR,
2190 				  "status: { Busy }\n");
2191 			else
2192 				ata_dev_printk(qc->dev, KERN_ERR,
2193 				  "status: { %s%s%s%s}\n",
2194 				  res->command & ATA_DRDY ? "DRDY " : "",
2195 				  res->command & ATA_DF ? "DF " : "",
2196 				  res->command & ATA_DRQ ? "DRQ " : "",
2197 				  res->command & ATA_ERR ? "ERR " : "");
2198 		}
2199 
2200 		if (cmd->command != ATA_CMD_PACKET &&
2201 		    (res->feature & (ATA_ICRC | ATA_UNC | ATA_IDNF |
2202 				     ATA_ABORTED)))
2203 			ata_dev_printk(qc->dev, KERN_ERR,
2204 			  "error: { %s%s%s%s}\n",
2205 			  res->feature & ATA_ICRC ? "ICRC " : "",
2206 			  res->feature & ATA_UNC ? "UNC " : "",
2207 			  res->feature & ATA_IDNF ? "IDNF " : "",
2208 			  res->feature & ATA_ABORTED ? "ABRT " : "");
2209 	}
2210 }
2211 
2212 /**
2213  *	ata_eh_report - report error handling to user
2214  *	@ap: ATA port to report EH about
2215  *
2216  *	Report EH to user.
2217  *
2218  *	LOCKING:
2219  *	None.
2220  */
2221 void ata_eh_report(struct ata_port *ap)
2222 {
2223 	struct ata_link *link;
2224 
2225 	__ata_port_for_each_link(link, ap)
2226 		ata_eh_link_report(link);
2227 }
2228 
2229 static int ata_do_reset(struct ata_link *link, ata_reset_fn_t reset,
2230 			unsigned int *classes, unsigned long deadline,
2231 			bool clear_classes)
2232 {
2233 	struct ata_device *dev;
2234 
2235 	if (clear_classes)
2236 		ata_link_for_each_dev(dev, link)
2237 			classes[dev->devno] = ATA_DEV_UNKNOWN;
2238 
2239 	return reset(link, classes, deadline);
2240 }
2241 
2242 static int ata_eh_followup_srst_needed(struct ata_link *link,
2243 				       int rc, const unsigned int *classes)
2244 {
2245 	if ((link->flags & ATA_LFLAG_NO_SRST) || ata_link_offline(link))
2246 		return 0;
2247 	if (rc == -EAGAIN)
2248 		return 1;
2249 	if (sata_pmp_supported(link->ap) && ata_is_host_link(link))
2250 		return 1;
2251 	return 0;
2252 }
2253 
2254 int ata_eh_reset(struct ata_link *link, int classify,
2255 		 ata_prereset_fn_t prereset, ata_reset_fn_t softreset,
2256 		 ata_reset_fn_t hardreset, ata_postreset_fn_t postreset)
2257 {
2258 	struct ata_port *ap = link->ap;
2259 	struct ata_link *slave = ap->slave_link;
2260 	struct ata_eh_context *ehc = &link->eh_context;
2261 	struct ata_eh_context *sehc = &slave->eh_context;
2262 	unsigned int *classes = ehc->classes;
2263 	unsigned int lflags = link->flags;
2264 	int verbose = !(ehc->i.flags & ATA_EHI_QUIET);
2265 	int max_tries = 0, try = 0;
2266 	struct ata_link *failed_link;
2267 	struct ata_device *dev;
2268 	unsigned long deadline, now;
2269 	ata_reset_fn_t reset;
2270 	unsigned long flags;
2271 	u32 sstatus;
2272 	int nr_unknown, rc;
2273 
2274 	/*
2275 	 * Prepare to reset
2276 	 */
2277 	while (ata_eh_reset_timeouts[max_tries] != ULONG_MAX)
2278 		max_tries++;
2279 	if (link->flags & ATA_LFLAG_NO_HRST)
2280 		hardreset = NULL;
2281 	if (link->flags & ATA_LFLAG_NO_SRST)
2282 		softreset = NULL;
2283 
2284 	now = jiffies;
2285 	deadline = ata_deadline(ehc->last_reset, ATA_EH_RESET_COOL_DOWN);
2286 	if (time_before(now, deadline))
2287 		schedule_timeout_uninterruptible(deadline - now);
2288 
2289 	spin_lock_irqsave(ap->lock, flags);
2290 	ap->pflags |= ATA_PFLAG_RESETTING;
2291 	spin_unlock_irqrestore(ap->lock, flags);
2292 
2293 	ata_eh_about_to_do(link, NULL, ATA_EH_RESET);
2294 	ehc->last_reset = jiffies;
2295 
2296 	ata_link_for_each_dev(dev, link) {
2297 		/* If we issue an SRST then an ATA drive (not ATAPI)
2298 		 * may change configuration and be in PIO0 timing. If
2299 		 * we do a hard reset (or are coming from power on)
2300 		 * this is true for ATA or ATAPI. Until we've set a
2301 		 * suitable controller mode we should not touch the
2302 		 * bus as we may be talking too fast.
2303 		 */
2304 		dev->pio_mode = XFER_PIO_0;
2305 
2306 		/* If the controller has a pio mode setup function
2307 		 * then use it to set the chipset to rights. Don't
2308 		 * touch the DMA setup as that will be dealt with when
2309 		 * configuring devices.
2310 		 */
2311 		if (ap->ops->set_piomode)
2312 			ap->ops->set_piomode(ap, dev);
2313 	}
2314 
2315 	/* prefer hardreset */
2316 	reset = NULL;
2317 	ehc->i.action &= ~ATA_EH_RESET;
2318 	if (hardreset) {
2319 		reset = hardreset;
2320 		ehc->i.action |= ATA_EH_HARDRESET;
2321 	} else if (softreset) {
2322 		reset = softreset;
2323 		ehc->i.action |= ATA_EH_SOFTRESET;
2324 	}
2325 
2326 	if (prereset) {
2327 		unsigned long deadline = ata_deadline(jiffies,
2328 						      ATA_EH_PRERESET_TIMEOUT);
2329 
2330 		if (slave) {
2331 			sehc->i.action &= ~ATA_EH_RESET;
2332 			sehc->i.action |= ehc->i.action;
2333 		}
2334 
2335 		rc = prereset(link, deadline);
2336 
2337 		/* If present, do prereset on slave link too.  Reset
2338 		 * is skipped iff both master and slave links report
2339 		 * -ENOENT or clear ATA_EH_RESET.
2340 		 */
2341 		if (slave && (rc == 0 || rc == -ENOENT)) {
2342 			int tmp;
2343 
2344 			tmp = prereset(slave, deadline);
2345 			if (tmp != -ENOENT)
2346 				rc = tmp;
2347 
2348 			ehc->i.action |= sehc->i.action;
2349 		}
2350 
2351 		if (rc) {
2352 			if (rc == -ENOENT) {
2353 				ata_link_printk(link, KERN_DEBUG,
2354 						"port disabled. ignoring.\n");
2355 				ehc->i.action &= ~ATA_EH_RESET;
2356 
2357 				ata_link_for_each_dev(dev, link)
2358 					classes[dev->devno] = ATA_DEV_NONE;
2359 
2360 				rc = 0;
2361 			} else
2362 				ata_link_printk(link, KERN_ERR,
2363 					"prereset failed (errno=%d)\n", rc);
2364 			goto out;
2365 		}
2366 
2367 		/* prereset() might have cleared ATA_EH_RESET.  If so,
2368 		 * bang classes and return.
2369 		 */
2370 		if (reset && !(ehc->i.action & ATA_EH_RESET)) {
2371 			ata_link_for_each_dev(dev, link)
2372 				classes[dev->devno] = ATA_DEV_NONE;
2373 			rc = 0;
2374 			goto out;
2375 		}
2376 	}
2377 
2378  retry:
2379 	/*
2380 	 * Perform reset
2381 	 */
2382 	ehc->last_reset = jiffies;
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 		if (reset == hardreset)
2395 			ehc->i.flags |= ATA_EHI_DID_HARDRESET;
2396 		else
2397 			ehc->i.flags |= ATA_EHI_DID_SOFTRESET;
2398 
2399 		rc = ata_do_reset(link, reset, classes, deadline, true);
2400 		if (rc && rc != -EAGAIN) {
2401 			failed_link = link;
2402 			goto fail;
2403 		}
2404 
2405 		/* hardreset slave link if existent */
2406 		if (slave && reset == hardreset) {
2407 			int tmp;
2408 
2409 			if (verbose)
2410 				ata_link_printk(slave, KERN_INFO,
2411 						"hard resetting link\n");
2412 
2413 			ata_eh_about_to_do(slave, NULL, ATA_EH_RESET);
2414 			tmp = ata_do_reset(slave, reset, classes, deadline,
2415 					   false);
2416 			switch (tmp) {
2417 			case -EAGAIN:
2418 				rc = -EAGAIN;
2419 			case 0:
2420 				break;
2421 			default:
2422 				failed_link = slave;
2423 				rc = tmp;
2424 				goto fail;
2425 			}
2426 		}
2427 
2428 		/* perform follow-up SRST if necessary */
2429 		if (reset == hardreset &&
2430 		    ata_eh_followup_srst_needed(link, rc, classes)) {
2431 			reset = softreset;
2432 
2433 			if (!reset) {
2434 				ata_link_printk(link, KERN_ERR,
2435 						"follow-up softreset required "
2436 						"but no softreset avaliable\n");
2437 				failed_link = link;
2438 				rc = -EINVAL;
2439 				goto fail;
2440 			}
2441 
2442 			ata_eh_about_to_do(link, NULL, ATA_EH_RESET);
2443 			rc = ata_do_reset(link, reset, classes, deadline, true);
2444 		}
2445 	} else {
2446 		if (verbose)
2447 			ata_link_printk(link, KERN_INFO, "no reset method "
2448 					"available, skipping reset\n");
2449 		if (!(lflags & ATA_LFLAG_ASSUME_CLASS))
2450 			lflags |= ATA_LFLAG_ASSUME_ATA;
2451 	}
2452 
2453 	/*
2454 	 * Post-reset processing
2455 	 */
2456 	ata_link_for_each_dev(dev, link) {
2457 		/* After the reset, the device state is PIO 0 and the
2458 		 * controller state is undefined.  Reset also wakes up
2459 		 * drives from sleeping mode.
2460 		 */
2461 		dev->pio_mode = XFER_PIO_0;
2462 		dev->flags &= ~ATA_DFLAG_SLEEPING;
2463 
2464 		if (!ata_phys_link_offline(ata_dev_phys_link(dev))) {
2465 			/* apply class override */
2466 			if (lflags & ATA_LFLAG_ASSUME_ATA)
2467 				classes[dev->devno] = ATA_DEV_ATA;
2468 			else if (lflags & ATA_LFLAG_ASSUME_SEMB)
2469 				classes[dev->devno] = ATA_DEV_SEMB_UNSUP;
2470 		} else
2471 			classes[dev->devno] = ATA_DEV_NONE;
2472 	}
2473 
2474 	/* record current link speed */
2475 	if (sata_scr_read(link, SCR_STATUS, &sstatus) == 0)
2476 		link->sata_spd = (sstatus >> 4) & 0xf;
2477 	if (slave && sata_scr_read(slave, SCR_STATUS, &sstatus) == 0)
2478 		slave->sata_spd = (sstatus >> 4) & 0xf;
2479 
2480 	/* thaw the port */
2481 	if (ata_is_host_link(link))
2482 		ata_eh_thaw_port(ap);
2483 
2484 	/* postreset() should clear hardware SError.  Although SError
2485 	 * is cleared during link resume, clearing SError here is
2486 	 * necessary as some PHYs raise hotplug events after SRST.
2487 	 * This introduces race condition where hotplug occurs between
2488 	 * reset and here.  This race is mediated by cross checking
2489 	 * link onlineness and classification result later.
2490 	 */
2491 	if (postreset) {
2492 		postreset(link, classes);
2493 		if (slave)
2494 			postreset(slave, classes);
2495 	}
2496 
2497 	/* clear cached SError */
2498 	spin_lock_irqsave(link->ap->lock, flags);
2499 	link->eh_info.serror = 0;
2500 	if (slave)
2501 		slave->eh_info.serror = 0;
2502 	spin_unlock_irqrestore(link->ap->lock, flags);
2503 
2504 	/* Make sure onlineness and classification result correspond.
2505 	 * Hotplug could have happened during reset and some
2506 	 * controllers fail to wait while a drive is spinning up after
2507 	 * being hotplugged causing misdetection.  By cross checking
2508 	 * link onlineness and classification result, those conditions
2509 	 * can be reliably detected and retried.
2510 	 */
2511 	nr_unknown = 0;
2512 	ata_link_for_each_dev(dev, link) {
2513 		/* convert all ATA_DEV_UNKNOWN to ATA_DEV_NONE */
2514 		if (classes[dev->devno] == ATA_DEV_UNKNOWN) {
2515 			classes[dev->devno] = ATA_DEV_NONE;
2516 			if (ata_phys_link_online(ata_dev_phys_link(dev)))
2517 				nr_unknown++;
2518 		}
2519 	}
2520 
2521 	if (classify && nr_unknown) {
2522 		if (try < max_tries) {
2523 			ata_link_printk(link, KERN_WARNING, "link online but "
2524 				       "device misclassified, retrying\n");
2525 			failed_link = link;
2526 			rc = -EAGAIN;
2527 			goto fail;
2528 		}
2529 		ata_link_printk(link, KERN_WARNING,
2530 			       "link online but device misclassified, "
2531 			       "device detection might fail\n");
2532 	}
2533 
2534 	/* reset successful, schedule revalidation */
2535 	ata_eh_done(link, NULL, ATA_EH_RESET);
2536 	if (slave)
2537 		ata_eh_done(slave, NULL, ATA_EH_RESET);
2538 	ehc->last_reset = jiffies;
2539 	ehc->i.action |= ATA_EH_REVALIDATE;
2540 
2541 	rc = 0;
2542  out:
2543 	/* clear hotplug flag */
2544 	ehc->i.flags &= ~ATA_EHI_HOTPLUGGED;
2545 	if (slave)
2546 		sehc->i.flags &= ~ATA_EHI_HOTPLUGGED;
2547 
2548 	spin_lock_irqsave(ap->lock, flags);
2549 	ap->pflags &= ~ATA_PFLAG_RESETTING;
2550 	spin_unlock_irqrestore(ap->lock, flags);
2551 
2552 	return rc;
2553 
2554  fail:
2555 	/* if SCR isn't accessible on a fan-out port, PMP needs to be reset */
2556 	if (!ata_is_host_link(link) &&
2557 	    sata_scr_read(link, SCR_STATUS, &sstatus))
2558 		rc = -ERESTART;
2559 
2560 	if (rc == -ERESTART || try >= max_tries)
2561 		goto out;
2562 
2563 	now = jiffies;
2564 	if (time_before(now, deadline)) {
2565 		unsigned long delta = deadline - now;
2566 
2567 		ata_link_printk(failed_link, KERN_WARNING,
2568 			"reset failed (errno=%d), retrying in %u secs\n",
2569 			rc, DIV_ROUND_UP(jiffies_to_msecs(delta), 1000));
2570 
2571 		while (delta)
2572 			delta = schedule_timeout_uninterruptible(delta);
2573 	}
2574 
2575 	if (try == max_tries - 1) {
2576 		sata_down_spd_limit(link);
2577 		if (slave)
2578 			sata_down_spd_limit(slave);
2579 	} else if (rc == -EPIPE)
2580 		sata_down_spd_limit(failed_link);
2581 
2582 	if (hardreset)
2583 		reset = hardreset;
2584 	goto retry;
2585 }
2586 
2587 static inline void ata_eh_pull_park_action(struct ata_port *ap)
2588 {
2589 	struct ata_link *link;
2590 	struct ata_device *dev;
2591 	unsigned long flags;
2592 
2593 	/*
2594 	 * This function can be thought of as an extended version of
2595 	 * ata_eh_about_to_do() specially crafted to accommodate the
2596 	 * requirements of ATA_EH_PARK handling. Since the EH thread
2597 	 * does not leave the do {} while () loop in ata_eh_recover as
2598 	 * long as the timeout for a park request to *one* device on
2599 	 * the port has not expired, and since we still want to pick
2600 	 * up park requests to other devices on the same port or
2601 	 * timeout updates for the same device, we have to pull
2602 	 * ATA_EH_PARK actions from eh_info into eh_context.i
2603 	 * ourselves at the beginning of each pass over the loop.
2604 	 *
2605 	 * Additionally, all write accesses to &ap->park_req_pending
2606 	 * through INIT_COMPLETION() (see below) or complete_all()
2607 	 * (see ata_scsi_park_store()) are protected by the host lock.
2608 	 * As a result we have that park_req_pending.done is zero on
2609 	 * exit from this function, i.e. when ATA_EH_PARK actions for
2610 	 * *all* devices on port ap have been pulled into the
2611 	 * respective eh_context structs. If, and only if,
2612 	 * park_req_pending.done is non-zero by the time we reach
2613 	 * wait_for_completion_timeout(), another ATA_EH_PARK action
2614 	 * has been scheduled for at least one of the devices on port
2615 	 * ap and we have to cycle over the do {} while () loop in
2616 	 * ata_eh_recover() again.
2617 	 */
2618 
2619 	spin_lock_irqsave(ap->lock, flags);
2620 	INIT_COMPLETION(ap->park_req_pending);
2621 	ata_port_for_each_link(link, ap) {
2622 		ata_link_for_each_dev(dev, link) {
2623 			struct ata_eh_info *ehi = &link->eh_info;
2624 
2625 			link->eh_context.i.dev_action[dev->devno] |=
2626 				ehi->dev_action[dev->devno] & ATA_EH_PARK;
2627 			ata_eh_clear_action(link, dev, ehi, ATA_EH_PARK);
2628 		}
2629 	}
2630 	spin_unlock_irqrestore(ap->lock, flags);
2631 }
2632 
2633 static void ata_eh_park_issue_cmd(struct ata_device *dev, int park)
2634 {
2635 	struct ata_eh_context *ehc = &dev->link->eh_context;
2636 	struct ata_taskfile tf;
2637 	unsigned int err_mask;
2638 
2639 	ata_tf_init(dev, &tf);
2640 	if (park) {
2641 		ehc->unloaded_mask |= 1 << dev->devno;
2642 		tf.command = ATA_CMD_IDLEIMMEDIATE;
2643 		tf.feature = 0x44;
2644 		tf.lbal = 0x4c;
2645 		tf.lbam = 0x4e;
2646 		tf.lbah = 0x55;
2647 	} else {
2648 		ehc->unloaded_mask &= ~(1 << dev->devno);
2649 		tf.command = ATA_CMD_CHK_POWER;
2650 	}
2651 
2652 	tf.flags |= ATA_TFLAG_DEVICE | ATA_TFLAG_ISADDR;
2653 	tf.protocol |= ATA_PROT_NODATA;
2654 	err_mask = ata_exec_internal(dev, &tf, NULL, DMA_NONE, NULL, 0, 0);
2655 	if (park && (err_mask || tf.lbal != 0xc4)) {
2656 		ata_dev_printk(dev, KERN_ERR, "head unload failed!\n");
2657 		ehc->unloaded_mask &= ~(1 << dev->devno);
2658 	}
2659 }
2660 
2661 static int ata_eh_revalidate_and_attach(struct ata_link *link,
2662 					struct ata_device **r_failed_dev)
2663 {
2664 	struct ata_port *ap = link->ap;
2665 	struct ata_eh_context *ehc = &link->eh_context;
2666 	struct ata_device *dev;
2667 	unsigned int new_mask = 0;
2668 	unsigned long flags;
2669 	int rc = 0;
2670 
2671 	DPRINTK("ENTER\n");
2672 
2673 	/* For PATA drive side cable detection to work, IDENTIFY must
2674 	 * be done backwards such that PDIAG- is released by the slave
2675 	 * device before the master device is identified.
2676 	 */
2677 	ata_link_for_each_dev_reverse(dev, link) {
2678 		unsigned int action = ata_eh_dev_action(dev);
2679 		unsigned int readid_flags = 0;
2680 
2681 		if (ehc->i.flags & ATA_EHI_DID_RESET)
2682 			readid_flags |= ATA_READID_POSTRESET;
2683 
2684 		if ((action & ATA_EH_REVALIDATE) && ata_dev_enabled(dev)) {
2685 			WARN_ON(dev->class == ATA_DEV_PMP);
2686 
2687 			if (ata_phys_link_offline(ata_dev_phys_link(dev))) {
2688 				rc = -EIO;
2689 				goto err;
2690 			}
2691 
2692 			ata_eh_about_to_do(link, dev, ATA_EH_REVALIDATE);
2693 			rc = ata_dev_revalidate(dev, ehc->classes[dev->devno],
2694 						readid_flags);
2695 			if (rc)
2696 				goto err;
2697 
2698 			ata_eh_done(link, dev, ATA_EH_REVALIDATE);
2699 
2700 			/* Configuration may have changed, reconfigure
2701 			 * transfer mode.
2702 			 */
2703 			ehc->i.flags |= ATA_EHI_SETMODE;
2704 
2705 			/* schedule the scsi_rescan_device() here */
2706 			queue_work(ata_aux_wq, &(ap->scsi_rescan_task));
2707 		} else if (dev->class == ATA_DEV_UNKNOWN &&
2708 			   ehc->tries[dev->devno] &&
2709 			   ata_class_enabled(ehc->classes[dev->devno])) {
2710 			dev->class = ehc->classes[dev->devno];
2711 
2712 			if (dev->class == ATA_DEV_PMP)
2713 				rc = sata_pmp_attach(dev);
2714 			else
2715 				rc = ata_dev_read_id(dev, &dev->class,
2716 						     readid_flags, dev->id);
2717 			switch (rc) {
2718 			case 0:
2719 				new_mask |= 1 << dev->devno;
2720 				break;
2721 			case -ENOENT:
2722 				/* IDENTIFY was issued to non-existent
2723 				 * device.  No need to reset.  Just
2724 				 * thaw and kill the device.
2725 				 */
2726 				ata_eh_thaw_port(ap);
2727 				dev->class = ATA_DEV_UNKNOWN;
2728 				break;
2729 			default:
2730 				dev->class = ATA_DEV_UNKNOWN;
2731 				goto err;
2732 			}
2733 		}
2734 	}
2735 
2736 	/* PDIAG- should have been released, ask cable type if post-reset */
2737 	if ((ehc->i.flags & ATA_EHI_DID_RESET) && ata_is_host_link(link)) {
2738 		if (ap->ops->cable_detect)
2739 			ap->cbl = ap->ops->cable_detect(ap);
2740 		ata_force_cbl(ap);
2741 	}
2742 
2743 	/* Configure new devices forward such that user doesn't see
2744 	 * device detection messages backwards.
2745 	 */
2746 	ata_link_for_each_dev(dev, link) {
2747 		if (!(new_mask & (1 << dev->devno)) ||
2748 		    dev->class == ATA_DEV_PMP)
2749 			continue;
2750 
2751 		ehc->i.flags |= ATA_EHI_PRINTINFO;
2752 		rc = ata_dev_configure(dev);
2753 		ehc->i.flags &= ~ATA_EHI_PRINTINFO;
2754 		if (rc)
2755 			goto err;
2756 
2757 		spin_lock_irqsave(ap->lock, flags);
2758 		ap->pflags |= ATA_PFLAG_SCSI_HOTPLUG;
2759 		spin_unlock_irqrestore(ap->lock, flags);
2760 
2761 		/* new device discovered, configure xfermode */
2762 		ehc->i.flags |= ATA_EHI_SETMODE;
2763 	}
2764 
2765 	return 0;
2766 
2767  err:
2768 	*r_failed_dev = dev;
2769 	DPRINTK("EXIT rc=%d\n", rc);
2770 	return rc;
2771 }
2772 
2773 /**
2774  *	ata_set_mode - Program timings and issue SET FEATURES - XFER
2775  *	@link: link on which timings will be programmed
2776  *	@r_failed_dev: out paramter for failed device
2777  *
2778  *	Set ATA device disk transfer mode (PIO3, UDMA6, etc.).  If
2779  *	ata_set_mode() fails, pointer to the failing device is
2780  *	returned in @r_failed_dev.
2781  *
2782  *	LOCKING:
2783  *	PCI/etc. bus probe sem.
2784  *
2785  *	RETURNS:
2786  *	0 on success, negative errno otherwise
2787  */
2788 int ata_set_mode(struct ata_link *link, struct ata_device **r_failed_dev)
2789 {
2790 	struct ata_port *ap = link->ap;
2791 	struct ata_device *dev;
2792 	int rc;
2793 
2794 	/* if data transfer is verified, clear DUBIOUS_XFER on ering top */
2795 	ata_link_for_each_dev(dev, link) {
2796 		if (!ata_dev_enabled(dev))
2797 			continue;
2798 
2799 		if (!(dev->flags & ATA_DFLAG_DUBIOUS_XFER)) {
2800 			struct ata_ering_entry *ent;
2801 
2802 			ent = ata_ering_top(&dev->ering);
2803 			if (ent)
2804 				ent->eflags &= ~ATA_EFLAG_DUBIOUS_XFER;
2805 		}
2806 	}
2807 
2808 	/* has private set_mode? */
2809 	if (ap->ops->set_mode)
2810 		rc = ap->ops->set_mode(link, r_failed_dev);
2811 	else
2812 		rc = ata_do_set_mode(link, r_failed_dev);
2813 
2814 	/* if transfer mode has changed, set DUBIOUS_XFER on device */
2815 	ata_link_for_each_dev(dev, link) {
2816 		struct ata_eh_context *ehc = &link->eh_context;
2817 		u8 saved_xfer_mode = ehc->saved_xfer_mode[dev->devno];
2818 		u8 saved_ncq = !!(ehc->saved_ncq_enabled & (1 << dev->devno));
2819 
2820 		if (!ata_dev_enabled(dev))
2821 			continue;
2822 
2823 		if (dev->xfer_mode != saved_xfer_mode ||
2824 		    ata_ncq_enabled(dev) != saved_ncq)
2825 			dev->flags |= ATA_DFLAG_DUBIOUS_XFER;
2826 	}
2827 
2828 	return rc;
2829 }
2830 
2831 /**
2832  *	atapi_eh_clear_ua - Clear ATAPI UNIT ATTENTION after reset
2833  *	@dev: ATAPI device to clear UA for
2834  *
2835  *	Resets and other operations can make an ATAPI device raise
2836  *	UNIT ATTENTION which causes the next operation to fail.  This
2837  *	function clears UA.
2838  *
2839  *	LOCKING:
2840  *	EH context (may sleep).
2841  *
2842  *	RETURNS:
2843  *	0 on success, -errno on failure.
2844  */
2845 static int atapi_eh_clear_ua(struct ata_device *dev)
2846 {
2847 	int i;
2848 
2849 	for (i = 0; i < ATA_EH_UA_TRIES; i++) {
2850 		u8 sense_buffer[SCSI_SENSE_BUFFERSIZE];
2851 		u8 sense_key = 0;
2852 		unsigned int err_mask;
2853 
2854 		err_mask = atapi_eh_tur(dev, &sense_key);
2855 		if (err_mask != 0 && err_mask != AC_ERR_DEV) {
2856 			ata_dev_printk(dev, KERN_WARNING, "TEST_UNIT_READY "
2857 				"failed (err_mask=0x%x)\n", err_mask);
2858 			return -EIO;
2859 		}
2860 
2861 		if (!err_mask || sense_key != UNIT_ATTENTION)
2862 			return 0;
2863 
2864 		err_mask = atapi_eh_request_sense(dev, sense_buffer, sense_key);
2865 		if (err_mask) {
2866 			ata_dev_printk(dev, KERN_WARNING, "failed to clear "
2867 				"UNIT ATTENTION (err_mask=0x%x)\n", err_mask);
2868 			return -EIO;
2869 		}
2870 	}
2871 
2872 	ata_dev_printk(dev, KERN_WARNING,
2873 		"UNIT ATTENTION persists after %d tries\n", ATA_EH_UA_TRIES);
2874 
2875 	return 0;
2876 }
2877 
2878 static int ata_link_nr_enabled(struct ata_link *link)
2879 {
2880 	struct ata_device *dev;
2881 	int cnt = 0;
2882 
2883 	ata_link_for_each_dev(dev, link)
2884 		if (ata_dev_enabled(dev))
2885 			cnt++;
2886 	return cnt;
2887 }
2888 
2889 static int ata_link_nr_vacant(struct ata_link *link)
2890 {
2891 	struct ata_device *dev;
2892 	int cnt = 0;
2893 
2894 	ata_link_for_each_dev(dev, link)
2895 		if (dev->class == ATA_DEV_UNKNOWN)
2896 			cnt++;
2897 	return cnt;
2898 }
2899 
2900 static int ata_eh_skip_recovery(struct ata_link *link)
2901 {
2902 	struct ata_port *ap = link->ap;
2903 	struct ata_eh_context *ehc = &link->eh_context;
2904 	struct ata_device *dev;
2905 
2906 	/* skip disabled links */
2907 	if (link->flags & ATA_LFLAG_DISABLED)
2908 		return 1;
2909 
2910 	/* thaw frozen port and recover failed devices */
2911 	if ((ap->pflags & ATA_PFLAG_FROZEN) || ata_link_nr_enabled(link))
2912 		return 0;
2913 
2914 	/* reset at least once if reset is requested */
2915 	if ((ehc->i.action & ATA_EH_RESET) &&
2916 	    !(ehc->i.flags & ATA_EHI_DID_RESET))
2917 		return 0;
2918 
2919 	/* skip if class codes for all vacant slots are ATA_DEV_NONE */
2920 	ata_link_for_each_dev(dev, link) {
2921 		if (dev->class == ATA_DEV_UNKNOWN &&
2922 		    ehc->classes[dev->devno] != ATA_DEV_NONE)
2923 			return 0;
2924 	}
2925 
2926 	return 1;
2927 }
2928 
2929 static int ata_eh_schedule_probe(struct ata_device *dev)
2930 {
2931 	struct ata_eh_context *ehc = &dev->link->eh_context;
2932 
2933 	if (!(ehc->i.probe_mask & (1 << dev->devno)) ||
2934 	    (ehc->did_probe_mask & (1 << dev->devno)))
2935 		return 0;
2936 
2937 	ata_eh_detach_dev(dev);
2938 	ata_dev_init(dev);
2939 	ehc->did_probe_mask |= (1 << dev->devno);
2940 	ehc->i.action |= ATA_EH_RESET;
2941 	ehc->saved_xfer_mode[dev->devno] = 0;
2942 	ehc->saved_ncq_enabled &= ~(1 << dev->devno);
2943 
2944 	return 1;
2945 }
2946 
2947 static int ata_eh_handle_dev_fail(struct ata_device *dev, int err)
2948 {
2949 	struct ata_eh_context *ehc = &dev->link->eh_context;
2950 
2951 	ehc->tries[dev->devno]--;
2952 
2953 	switch (err) {
2954 	case -ENODEV:
2955 		/* device missing or wrong IDENTIFY data, schedule probing */
2956 		ehc->i.probe_mask |= (1 << dev->devno);
2957 	case -EINVAL:
2958 		/* give it just one more chance */
2959 		ehc->tries[dev->devno] = min(ehc->tries[dev->devno], 1);
2960 	case -EIO:
2961 		if (ehc->tries[dev->devno] == 1 && dev->pio_mode > XFER_PIO_0) {
2962 			/* This is the last chance, better to slow
2963 			 * down than lose it.
2964 			 */
2965 			sata_down_spd_limit(ata_dev_phys_link(dev));
2966 			ata_down_xfermask_limit(dev, ATA_DNXFER_PIO);
2967 		}
2968 	}
2969 
2970 	if (ata_dev_enabled(dev) && !ehc->tries[dev->devno]) {
2971 		/* disable device if it has used up all its chances */
2972 		ata_dev_disable(dev);
2973 
2974 		/* detach if offline */
2975 		if (ata_phys_link_offline(ata_dev_phys_link(dev)))
2976 			ata_eh_detach_dev(dev);
2977 
2978 		/* schedule probe if necessary */
2979 		if (ata_eh_schedule_probe(dev)) {
2980 			ehc->tries[dev->devno] = ATA_EH_DEV_TRIES;
2981 			memset(ehc->cmd_timeout_idx[dev->devno], 0,
2982 			       sizeof(ehc->cmd_timeout_idx[dev->devno]));
2983 		}
2984 
2985 		return 1;
2986 	} else {
2987 		ehc->i.action |= ATA_EH_RESET;
2988 		return 0;
2989 	}
2990 }
2991 
2992 /**
2993  *	ata_eh_recover - recover host port after error
2994  *	@ap: host port to recover
2995  *	@prereset: prereset method (can be NULL)
2996  *	@softreset: softreset method (can be NULL)
2997  *	@hardreset: hardreset method (can be NULL)
2998  *	@postreset: postreset method (can be NULL)
2999  *	@r_failed_link: out parameter for failed link
3000  *
3001  *	This is the alpha and omega, eum and yang, heart and soul of
3002  *	libata exception handling.  On entry, actions required to
3003  *	recover each link and hotplug requests are recorded in the
3004  *	link's eh_context.  This function executes all the operations
3005  *	with appropriate retrials and fallbacks to resurrect failed
3006  *	devices, detach goners and greet newcomers.
3007  *
3008  *	LOCKING:
3009  *	Kernel thread context (may sleep).
3010  *
3011  *	RETURNS:
3012  *	0 on success, -errno on failure.
3013  */
3014 int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
3015 		   ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
3016 		   ata_postreset_fn_t postreset,
3017 		   struct ata_link **r_failed_link)
3018 {
3019 	struct ata_link *link;
3020 	struct ata_device *dev;
3021 	int nr_failed_devs;
3022 	int rc;
3023 	unsigned long flags, deadline;
3024 
3025 	DPRINTK("ENTER\n");
3026 
3027 	/* prep for recovery */
3028 	ata_port_for_each_link(link, ap) {
3029 		struct ata_eh_context *ehc = &link->eh_context;
3030 
3031 		/* re-enable link? */
3032 		if (ehc->i.action & ATA_EH_ENABLE_LINK) {
3033 			ata_eh_about_to_do(link, NULL, ATA_EH_ENABLE_LINK);
3034 			spin_lock_irqsave(ap->lock, flags);
3035 			link->flags &= ~ATA_LFLAG_DISABLED;
3036 			spin_unlock_irqrestore(ap->lock, flags);
3037 			ata_eh_done(link, NULL, ATA_EH_ENABLE_LINK);
3038 		}
3039 
3040 		ata_link_for_each_dev(dev, link) {
3041 			if (link->flags & ATA_LFLAG_NO_RETRY)
3042 				ehc->tries[dev->devno] = 1;
3043 			else
3044 				ehc->tries[dev->devno] = ATA_EH_DEV_TRIES;
3045 
3046 			/* collect port action mask recorded in dev actions */
3047 			ehc->i.action |= ehc->i.dev_action[dev->devno] &
3048 					 ~ATA_EH_PERDEV_MASK;
3049 			ehc->i.dev_action[dev->devno] &= ATA_EH_PERDEV_MASK;
3050 
3051 			/* process hotplug request */
3052 			if (dev->flags & ATA_DFLAG_DETACH)
3053 				ata_eh_detach_dev(dev);
3054 
3055 			/* schedule probe if necessary */
3056 			if (!ata_dev_enabled(dev))
3057 				ata_eh_schedule_probe(dev);
3058 		}
3059 	}
3060 
3061  retry:
3062 	rc = 0;
3063 	nr_failed_devs = 0;
3064 
3065 	/* if UNLOADING, finish immediately */
3066 	if (ap->pflags & ATA_PFLAG_UNLOADING)
3067 		goto out;
3068 
3069 	/* prep for EH */
3070 	ata_port_for_each_link(link, ap) {
3071 		struct ata_eh_context *ehc = &link->eh_context;
3072 
3073 		/* skip EH if possible. */
3074 		if (ata_eh_skip_recovery(link))
3075 			ehc->i.action = 0;
3076 
3077 		ata_link_for_each_dev(dev, link)
3078 			ehc->classes[dev->devno] = ATA_DEV_UNKNOWN;
3079 	}
3080 
3081 	/* reset */
3082 	ata_port_for_each_link(link, ap) {
3083 		struct ata_eh_context *ehc = &link->eh_context;
3084 
3085 		if (!(ehc->i.action & ATA_EH_RESET))
3086 			continue;
3087 
3088 		rc = ata_eh_reset(link, ata_link_nr_vacant(link),
3089 				  prereset, softreset, hardreset, postreset);
3090 		if (rc) {
3091 			ata_link_printk(link, KERN_ERR,
3092 					"reset failed, giving up\n");
3093 			goto out;
3094 		}
3095 	}
3096 
3097 	do {
3098 		unsigned long now;
3099 
3100 		/*
3101 		 * clears ATA_EH_PARK in eh_info and resets
3102 		 * ap->park_req_pending
3103 		 */
3104 		ata_eh_pull_park_action(ap);
3105 
3106 		deadline = jiffies;
3107 		ata_port_for_each_link(link, ap) {
3108 			ata_link_for_each_dev(dev, link) {
3109 				struct ata_eh_context *ehc = &link->eh_context;
3110 				unsigned long tmp;
3111 
3112 				if (dev->class != ATA_DEV_ATA)
3113 					continue;
3114 				if (!(ehc->i.dev_action[dev->devno] &
3115 				      ATA_EH_PARK))
3116 					continue;
3117 				tmp = dev->unpark_deadline;
3118 				if (time_before(deadline, tmp))
3119 					deadline = tmp;
3120 				else if (time_before_eq(tmp, jiffies))
3121 					continue;
3122 				if (ehc->unloaded_mask & (1 << dev->devno))
3123 					continue;
3124 
3125 				ata_eh_park_issue_cmd(dev, 1);
3126 			}
3127 		}
3128 
3129 		now = jiffies;
3130 		if (time_before_eq(deadline, now))
3131 			break;
3132 
3133 		deadline = wait_for_completion_timeout(&ap->park_req_pending,
3134 						       deadline - now);
3135 	} while (deadline);
3136 	ata_port_for_each_link(link, ap) {
3137 		ata_link_for_each_dev(dev, link) {
3138 			if (!(link->eh_context.unloaded_mask &
3139 			      (1 << dev->devno)))
3140 				continue;
3141 
3142 			ata_eh_park_issue_cmd(dev, 0);
3143 			ata_eh_done(link, dev, ATA_EH_PARK);
3144 		}
3145 	}
3146 
3147 	/* the rest */
3148 	ata_port_for_each_link(link, ap) {
3149 		struct ata_eh_context *ehc = &link->eh_context;
3150 
3151 		/* revalidate existing devices and attach new ones */
3152 		rc = ata_eh_revalidate_and_attach(link, &dev);
3153 		if (rc)
3154 			goto dev_fail;
3155 
3156 		/* if PMP got attached, return, pmp EH will take care of it */
3157 		if (link->device->class == ATA_DEV_PMP) {
3158 			ehc->i.action = 0;
3159 			return 0;
3160 		}
3161 
3162 		/* configure transfer mode if necessary */
3163 		if (ehc->i.flags & ATA_EHI_SETMODE) {
3164 			rc = ata_set_mode(link, &dev);
3165 			if (rc)
3166 				goto dev_fail;
3167 			ehc->i.flags &= ~ATA_EHI_SETMODE;
3168 		}
3169 
3170 		/* If reset has been issued, clear UA to avoid
3171 		 * disrupting the current users of the device.
3172 		 */
3173 		if (ehc->i.flags & ATA_EHI_DID_RESET) {
3174 			ata_link_for_each_dev(dev, link) {
3175 				if (dev->class != ATA_DEV_ATAPI)
3176 					continue;
3177 				rc = atapi_eh_clear_ua(dev);
3178 				if (rc)
3179 					goto dev_fail;
3180 			}
3181 		}
3182 
3183 		/* configure link power saving */
3184 		if (ehc->i.action & ATA_EH_LPM)
3185 			ata_link_for_each_dev(dev, link)
3186 				ata_dev_enable_pm(dev, ap->pm_policy);
3187 
3188 		/* this link is okay now */
3189 		ehc->i.flags = 0;
3190 		continue;
3191 
3192 dev_fail:
3193 		nr_failed_devs++;
3194 		ata_eh_handle_dev_fail(dev, rc);
3195 
3196 		if (ap->pflags & ATA_PFLAG_FROZEN) {
3197 			/* PMP reset requires working host port.
3198 			 * Can't retry if it's frozen.
3199 			 */
3200 			if (sata_pmp_attached(ap))
3201 				goto out;
3202 			break;
3203 		}
3204 	}
3205 
3206 	if (nr_failed_devs)
3207 		goto retry;
3208 
3209  out:
3210 	if (rc && r_failed_link)
3211 		*r_failed_link = link;
3212 
3213 	DPRINTK("EXIT, rc=%d\n", rc);
3214 	return rc;
3215 }
3216 
3217 /**
3218  *	ata_eh_finish - finish up EH
3219  *	@ap: host port to finish EH for
3220  *
3221  *	Recovery is complete.  Clean up EH states and retry or finish
3222  *	failed qcs.
3223  *
3224  *	LOCKING:
3225  *	None.
3226  */
3227 void ata_eh_finish(struct ata_port *ap)
3228 {
3229 	int tag;
3230 
3231 	/* retry or finish qcs */
3232 	for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
3233 		struct ata_queued_cmd *qc = __ata_qc_from_tag(ap, tag);
3234 
3235 		if (!(qc->flags & ATA_QCFLAG_FAILED))
3236 			continue;
3237 
3238 		if (qc->err_mask) {
3239 			/* FIXME: Once EH migration is complete,
3240 			 * generate sense data in this function,
3241 			 * considering both err_mask and tf.
3242 			 */
3243 			if (qc->flags & ATA_QCFLAG_RETRY)
3244 				ata_eh_qc_retry(qc);
3245 			else
3246 				ata_eh_qc_complete(qc);
3247 		} else {
3248 			if (qc->flags & ATA_QCFLAG_SENSE_VALID) {
3249 				ata_eh_qc_complete(qc);
3250 			} else {
3251 				/* feed zero TF to sense generation */
3252 				memset(&qc->result_tf, 0, sizeof(qc->result_tf));
3253 				ata_eh_qc_retry(qc);
3254 			}
3255 		}
3256 	}
3257 
3258 	/* make sure nr_active_links is zero after EH */
3259 	WARN_ON(ap->nr_active_links);
3260 	ap->nr_active_links = 0;
3261 }
3262 
3263 /**
3264  *	ata_do_eh - do standard error handling
3265  *	@ap: host port to handle error for
3266  *
3267  *	@prereset: prereset method (can be NULL)
3268  *	@softreset: softreset method (can be NULL)
3269  *	@hardreset: hardreset method (can be NULL)
3270  *	@postreset: postreset method (can be NULL)
3271  *
3272  *	Perform standard error handling sequence.
3273  *
3274  *	LOCKING:
3275  *	Kernel thread context (may sleep).
3276  */
3277 void ata_do_eh(struct ata_port *ap, ata_prereset_fn_t prereset,
3278 	       ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
3279 	       ata_postreset_fn_t postreset)
3280 {
3281 	struct ata_device *dev;
3282 	int rc;
3283 
3284 	ata_eh_autopsy(ap);
3285 	ata_eh_report(ap);
3286 
3287 	rc = ata_eh_recover(ap, prereset, softreset, hardreset, postreset,
3288 			    NULL);
3289 	if (rc) {
3290 		ata_link_for_each_dev(dev, &ap->link)
3291 			ata_dev_disable(dev);
3292 	}
3293 
3294 	ata_eh_finish(ap);
3295 }
3296 
3297 /**
3298  *	ata_std_error_handler - standard error handler
3299  *	@ap: host port to handle error for
3300  *
3301  *	Standard error handler
3302  *
3303  *	LOCKING:
3304  *	Kernel thread context (may sleep).
3305  */
3306 void ata_std_error_handler(struct ata_port *ap)
3307 {
3308 	struct ata_port_operations *ops = ap->ops;
3309 	ata_reset_fn_t hardreset = ops->hardreset;
3310 
3311 	/* ignore built-in hardreset if SCR access is not available */
3312 	if (ata_is_builtin_hardreset(hardreset) && !sata_scr_valid(&ap->link))
3313 		hardreset = NULL;
3314 
3315 	ata_do_eh(ap, ops->prereset, ops->softreset, hardreset, ops->postreset);
3316 }
3317 
3318 #ifdef CONFIG_PM
3319 /**
3320  *	ata_eh_handle_port_suspend - perform port suspend operation
3321  *	@ap: port to suspend
3322  *
3323  *	Suspend @ap.
3324  *
3325  *	LOCKING:
3326  *	Kernel thread context (may sleep).
3327  */
3328 static void ata_eh_handle_port_suspend(struct ata_port *ap)
3329 {
3330 	unsigned long flags;
3331 	int rc = 0;
3332 
3333 	/* are we suspending? */
3334 	spin_lock_irqsave(ap->lock, flags);
3335 	if (!(ap->pflags & ATA_PFLAG_PM_PENDING) ||
3336 	    ap->pm_mesg.event == PM_EVENT_ON) {
3337 		spin_unlock_irqrestore(ap->lock, flags);
3338 		return;
3339 	}
3340 	spin_unlock_irqrestore(ap->lock, flags);
3341 
3342 	WARN_ON(ap->pflags & ATA_PFLAG_SUSPENDED);
3343 
3344 	/* tell ACPI we're suspending */
3345 	rc = ata_acpi_on_suspend(ap);
3346 	if (rc)
3347 		goto out;
3348 
3349 	/* suspend */
3350 	ata_eh_freeze_port(ap);
3351 
3352 	if (ap->ops->port_suspend)
3353 		rc = ap->ops->port_suspend(ap, ap->pm_mesg);
3354 
3355 	ata_acpi_set_state(ap, PMSG_SUSPEND);
3356  out:
3357 	/* report result */
3358 	spin_lock_irqsave(ap->lock, flags);
3359 
3360 	ap->pflags &= ~ATA_PFLAG_PM_PENDING;
3361 	if (rc == 0)
3362 		ap->pflags |= ATA_PFLAG_SUSPENDED;
3363 	else if (ap->pflags & ATA_PFLAG_FROZEN)
3364 		ata_port_schedule_eh(ap);
3365 
3366 	if (ap->pm_result) {
3367 		*ap->pm_result = rc;
3368 		ap->pm_result = NULL;
3369 	}
3370 
3371 	spin_unlock_irqrestore(ap->lock, flags);
3372 
3373 	return;
3374 }
3375 
3376 /**
3377  *	ata_eh_handle_port_resume - perform port resume operation
3378  *	@ap: port to resume
3379  *
3380  *	Resume @ap.
3381  *
3382  *	LOCKING:
3383  *	Kernel thread context (may sleep).
3384  */
3385 static void ata_eh_handle_port_resume(struct ata_port *ap)
3386 {
3387 	unsigned long flags;
3388 	int rc = 0;
3389 
3390 	/* are we resuming? */
3391 	spin_lock_irqsave(ap->lock, flags);
3392 	if (!(ap->pflags & ATA_PFLAG_PM_PENDING) ||
3393 	    ap->pm_mesg.event != PM_EVENT_ON) {
3394 		spin_unlock_irqrestore(ap->lock, flags);
3395 		return;
3396 	}
3397 	spin_unlock_irqrestore(ap->lock, flags);
3398 
3399 	WARN_ON(!(ap->pflags & ATA_PFLAG_SUSPENDED));
3400 
3401 	ata_acpi_set_state(ap, PMSG_ON);
3402 
3403 	if (ap->ops->port_resume)
3404 		rc = ap->ops->port_resume(ap);
3405 
3406 	/* tell ACPI that we're resuming */
3407 	ata_acpi_on_resume(ap);
3408 
3409 	/* report result */
3410 	spin_lock_irqsave(ap->lock, flags);
3411 	ap->pflags &= ~(ATA_PFLAG_PM_PENDING | ATA_PFLAG_SUSPENDED);
3412 	if (ap->pm_result) {
3413 		*ap->pm_result = rc;
3414 		ap->pm_result = NULL;
3415 	}
3416 	spin_unlock_irqrestore(ap->lock, flags);
3417 }
3418 #endif /* CONFIG_PM */
3419