xref: /linux/drivers/ata/libata-eh.c (revision a67ff6a54095e27093ea501fb143fefe51a536c2)
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/export.h>
38 #include <linux/pci.h>
39 #include <scsi/scsi.h>
40 #include <scsi/scsi_host.h>
41 #include <scsi/scsi_eh.h>
42 #include <scsi/scsi_device.h>
43 #include <scsi/scsi_cmnd.h>
44 #include <scsi/scsi_dbg.h>
45 #include "../scsi/scsi_transport_api.h"
46 
47 #include <linux/libata.h>
48 
49 #include "libata.h"
50 
51 enum {
52 	/* speed down verdicts */
53 	ATA_EH_SPDN_NCQ_OFF		= (1 << 0),
54 	ATA_EH_SPDN_SPEED_DOWN		= (1 << 1),
55 	ATA_EH_SPDN_FALLBACK_TO_PIO	= (1 << 2),
56 	ATA_EH_SPDN_KEEP_ERRORS		= (1 << 3),
57 
58 	/* error flags */
59 	ATA_EFLAG_IS_IO			= (1 << 0),
60 	ATA_EFLAG_DUBIOUS_XFER		= (1 << 1),
61 	ATA_EFLAG_OLD_ER                = (1 << 31),
62 
63 	/* error categories */
64 	ATA_ECAT_NONE			= 0,
65 	ATA_ECAT_ATA_BUS		= 1,
66 	ATA_ECAT_TOUT_HSM		= 2,
67 	ATA_ECAT_UNK_DEV		= 3,
68 	ATA_ECAT_DUBIOUS_NONE		= 4,
69 	ATA_ECAT_DUBIOUS_ATA_BUS	= 5,
70 	ATA_ECAT_DUBIOUS_TOUT_HSM	= 6,
71 	ATA_ECAT_DUBIOUS_UNK_DEV	= 7,
72 	ATA_ECAT_NR			= 8,
73 
74 	ATA_EH_CMD_DFL_TIMEOUT		=  5000,
75 
76 	/* always put at least this amount of time between resets */
77 	ATA_EH_RESET_COOL_DOWN		=  5000,
78 
79 	/* Waiting in ->prereset can never be reliable.  It's
80 	 * sometimes nice to wait there but it can't be depended upon;
81 	 * otherwise, we wouldn't be resetting.  Just give it enough
82 	 * time for most drives to spin up.
83 	 */
84 	ATA_EH_PRERESET_TIMEOUT		= 10000,
85 	ATA_EH_FASTDRAIN_INTERVAL	=  3000,
86 
87 	ATA_EH_UA_TRIES			= 5,
88 
89 	/* probe speed down parameters, see ata_eh_schedule_probe() */
90 	ATA_EH_PROBE_TRIAL_INTERVAL	= 60000,	/* 1 min */
91 	ATA_EH_PROBE_TRIALS		= 2,
92 };
93 
94 /* The following table determines how we sequence resets.  Each entry
95  * represents timeout for that try.  The first try can be soft or
96  * hardreset.  All others are hardreset if available.  In most cases
97  * the first reset w/ 10sec timeout should succeed.  Following entries
98  * are mostly for error handling, hotplug and retarded devices.
99  */
100 static const unsigned long ata_eh_reset_timeouts[] = {
101 	10000,	/* most drives spin up by 10sec */
102 	10000,	/* > 99% working drives spin up before 20sec */
103 	35000,	/* give > 30 secs of idleness for retarded devices */
104 	 5000,	/* and sweet one last chance */
105 	ULONG_MAX, /* > 1 min has elapsed, give up */
106 };
107 
108 static const unsigned long ata_eh_identify_timeouts[] = {
109 	 5000,	/* covers > 99% of successes and not too boring on failures */
110 	10000,  /* combined time till here is enough even for media access */
111 	30000,	/* for true idiots */
112 	ULONG_MAX,
113 };
114 
115 static const unsigned long ata_eh_flush_timeouts[] = {
116 	15000,	/* be generous with flush */
117 	15000,  /* ditto */
118 	30000,	/* and even more generous */
119 	ULONG_MAX,
120 };
121 
122 static const unsigned long ata_eh_other_timeouts[] = {
123 	 5000,	/* same rationale as identify timeout */
124 	10000,	/* ditto */
125 	/* but no merciful 30sec for other commands, it just isn't worth it */
126 	ULONG_MAX,
127 };
128 
129 struct ata_eh_cmd_timeout_ent {
130 	const u8		*commands;
131 	const unsigned long	*timeouts;
132 };
133 
134 /* The following table determines timeouts to use for EH internal
135  * commands.  Each table entry is a command class and matches the
136  * commands the entry applies to and the timeout table to use.
137  *
138  * On the retry after a command timed out, the next timeout value from
139  * the table is used.  If the table doesn't contain further entries,
140  * the last value is used.
141  *
142  * ehc->cmd_timeout_idx keeps track of which timeout to use per
143  * command class, so if SET_FEATURES times out on the first try, the
144  * next try will use the second timeout value only for that class.
145  */
146 #define CMDS(cmds...)	(const u8 []){ cmds, 0 }
147 static const struct ata_eh_cmd_timeout_ent
148 ata_eh_cmd_timeout_table[ATA_EH_CMD_TIMEOUT_TABLE_SIZE] = {
149 	{ .commands = CMDS(ATA_CMD_ID_ATA, ATA_CMD_ID_ATAPI),
150 	  .timeouts = ata_eh_identify_timeouts, },
151 	{ .commands = CMDS(ATA_CMD_READ_NATIVE_MAX, ATA_CMD_READ_NATIVE_MAX_EXT),
152 	  .timeouts = ata_eh_other_timeouts, },
153 	{ .commands = CMDS(ATA_CMD_SET_MAX, ATA_CMD_SET_MAX_EXT),
154 	  .timeouts = ata_eh_other_timeouts, },
155 	{ .commands = CMDS(ATA_CMD_SET_FEATURES),
156 	  .timeouts = ata_eh_other_timeouts, },
157 	{ .commands = CMDS(ATA_CMD_INIT_DEV_PARAMS),
158 	  .timeouts = ata_eh_other_timeouts, },
159 	{ .commands = CMDS(ATA_CMD_FLUSH, ATA_CMD_FLUSH_EXT),
160 	  .timeouts = ata_eh_flush_timeouts },
161 };
162 #undef CMDS
163 
164 static void __ata_port_freeze(struct ata_port *ap);
165 #ifdef CONFIG_PM
166 static void ata_eh_handle_port_suspend(struct ata_port *ap);
167 static void ata_eh_handle_port_resume(struct ata_port *ap);
168 #else /* CONFIG_PM */
169 static void ata_eh_handle_port_suspend(struct ata_port *ap)
170 { }
171 
172 static void ata_eh_handle_port_resume(struct ata_port *ap)
173 { }
174 #endif /* CONFIG_PM */
175 
176 static void __ata_ehi_pushv_desc(struct ata_eh_info *ehi, const char *fmt,
177 				 va_list args)
178 {
179 	ehi->desc_len += vscnprintf(ehi->desc + ehi->desc_len,
180 				     ATA_EH_DESC_LEN - ehi->desc_len,
181 				     fmt, args);
182 }
183 
184 /**
185  *	__ata_ehi_push_desc - push error description without adding separator
186  *	@ehi: target EHI
187  *	@fmt: printf format string
188  *
189  *	Format string according to @fmt and append it to @ehi->desc.
190  *
191  *	LOCKING:
192  *	spin_lock_irqsave(host lock)
193  */
194 void __ata_ehi_push_desc(struct ata_eh_info *ehi, const char *fmt, ...)
195 {
196 	va_list args;
197 
198 	va_start(args, fmt);
199 	__ata_ehi_pushv_desc(ehi, fmt, args);
200 	va_end(args);
201 }
202 
203 /**
204  *	ata_ehi_push_desc - push error description with separator
205  *	@ehi: target EHI
206  *	@fmt: printf format string
207  *
208  *	Format string according to @fmt and append it to @ehi->desc.
209  *	If @ehi->desc is not empty, ", " is added in-between.
210  *
211  *	LOCKING:
212  *	spin_lock_irqsave(host lock)
213  */
214 void ata_ehi_push_desc(struct ata_eh_info *ehi, const char *fmt, ...)
215 {
216 	va_list args;
217 
218 	if (ehi->desc_len)
219 		__ata_ehi_push_desc(ehi, ", ");
220 
221 	va_start(args, fmt);
222 	__ata_ehi_pushv_desc(ehi, fmt, args);
223 	va_end(args);
224 }
225 
226 /**
227  *	ata_ehi_clear_desc - clean error description
228  *	@ehi: target EHI
229  *
230  *	Clear @ehi->desc.
231  *
232  *	LOCKING:
233  *	spin_lock_irqsave(host lock)
234  */
235 void ata_ehi_clear_desc(struct ata_eh_info *ehi)
236 {
237 	ehi->desc[0] = '\0';
238 	ehi->desc_len = 0;
239 }
240 
241 /**
242  *	ata_port_desc - append port description
243  *	@ap: target ATA port
244  *	@fmt: printf format string
245  *
246  *	Format string according to @fmt and append it to port
247  *	description.  If port description is not empty, " " is added
248  *	in-between.  This function is to be used while initializing
249  *	ata_host.  The description is printed on host registration.
250  *
251  *	LOCKING:
252  *	None.
253  */
254 void ata_port_desc(struct ata_port *ap, const char *fmt, ...)
255 {
256 	va_list args;
257 
258 	WARN_ON(!(ap->pflags & ATA_PFLAG_INITIALIZING));
259 
260 	if (ap->link.eh_info.desc_len)
261 		__ata_ehi_push_desc(&ap->link.eh_info, " ");
262 
263 	va_start(args, fmt);
264 	__ata_ehi_pushv_desc(&ap->link.eh_info, fmt, args);
265 	va_end(args);
266 }
267 
268 #ifdef CONFIG_PCI
269 
270 /**
271  *	ata_port_pbar_desc - append PCI BAR description
272  *	@ap: target ATA port
273  *	@bar: target PCI BAR
274  *	@offset: offset into PCI BAR
275  *	@name: name of the area
276  *
277  *	If @offset is negative, this function formats a string which
278  *	contains the name, address, size and type of the BAR and
279  *	appends it to the port description.  If @offset is zero or
280  *	positive, only name and offsetted address is appended.
281  *
282  *	LOCKING:
283  *	None.
284  */
285 void ata_port_pbar_desc(struct ata_port *ap, int bar, ssize_t offset,
286 			const char *name)
287 {
288 	struct pci_dev *pdev = to_pci_dev(ap->host->dev);
289 	char *type = "";
290 	unsigned long long start, len;
291 
292 	if (pci_resource_flags(pdev, bar) & IORESOURCE_MEM)
293 		type = "m";
294 	else if (pci_resource_flags(pdev, bar) & IORESOURCE_IO)
295 		type = "i";
296 
297 	start = (unsigned long long)pci_resource_start(pdev, bar);
298 	len = (unsigned long long)pci_resource_len(pdev, bar);
299 
300 	if (offset < 0)
301 		ata_port_desc(ap, "%s %s%llu@0x%llx", name, type, len, start);
302 	else
303 		ata_port_desc(ap, "%s 0x%llx", name,
304 				start + (unsigned long long)offset);
305 }
306 
307 #endif /* CONFIG_PCI */
308 
309 static int ata_lookup_timeout_table(u8 cmd)
310 {
311 	int i;
312 
313 	for (i = 0; i < ATA_EH_CMD_TIMEOUT_TABLE_SIZE; i++) {
314 		const u8 *cur;
315 
316 		for (cur = ata_eh_cmd_timeout_table[i].commands; *cur; cur++)
317 			if (*cur == cmd)
318 				return i;
319 	}
320 
321 	return -1;
322 }
323 
324 /**
325  *	ata_internal_cmd_timeout - determine timeout for an internal command
326  *	@dev: target device
327  *	@cmd: internal command to be issued
328  *
329  *	Determine timeout for internal command @cmd for @dev.
330  *
331  *	LOCKING:
332  *	EH context.
333  *
334  *	RETURNS:
335  *	Determined timeout.
336  */
337 unsigned long ata_internal_cmd_timeout(struct ata_device *dev, u8 cmd)
338 {
339 	struct ata_eh_context *ehc = &dev->link->eh_context;
340 	int ent = ata_lookup_timeout_table(cmd);
341 	int idx;
342 
343 	if (ent < 0)
344 		return ATA_EH_CMD_DFL_TIMEOUT;
345 
346 	idx = ehc->cmd_timeout_idx[dev->devno][ent];
347 	return ata_eh_cmd_timeout_table[ent].timeouts[idx];
348 }
349 
350 /**
351  *	ata_internal_cmd_timed_out - notification for internal command timeout
352  *	@dev: target device
353  *	@cmd: internal command which timed out
354  *
355  *	Notify EH that internal command @cmd for @dev timed out.  This
356  *	function should be called only for commands whose timeouts are
357  *	determined using ata_internal_cmd_timeout().
358  *
359  *	LOCKING:
360  *	EH context.
361  */
362 void ata_internal_cmd_timed_out(struct ata_device *dev, u8 cmd)
363 {
364 	struct ata_eh_context *ehc = &dev->link->eh_context;
365 	int ent = ata_lookup_timeout_table(cmd);
366 	int idx;
367 
368 	if (ent < 0)
369 		return;
370 
371 	idx = ehc->cmd_timeout_idx[dev->devno][ent];
372 	if (ata_eh_cmd_timeout_table[ent].timeouts[idx + 1] != ULONG_MAX)
373 		ehc->cmd_timeout_idx[dev->devno][ent]++;
374 }
375 
376 static void ata_ering_record(struct ata_ering *ering, unsigned int eflags,
377 			     unsigned int err_mask)
378 {
379 	struct ata_ering_entry *ent;
380 
381 	WARN_ON(!err_mask);
382 
383 	ering->cursor++;
384 	ering->cursor %= ATA_ERING_SIZE;
385 
386 	ent = &ering->ring[ering->cursor];
387 	ent->eflags = eflags;
388 	ent->err_mask = err_mask;
389 	ent->timestamp = get_jiffies_64();
390 }
391 
392 static struct ata_ering_entry *ata_ering_top(struct ata_ering *ering)
393 {
394 	struct ata_ering_entry *ent = &ering->ring[ering->cursor];
395 
396 	if (ent->err_mask)
397 		return ent;
398 	return NULL;
399 }
400 
401 int ata_ering_map(struct ata_ering *ering,
402 		  int (*map_fn)(struct ata_ering_entry *, void *),
403 		  void *arg)
404 {
405 	int idx, rc = 0;
406 	struct ata_ering_entry *ent;
407 
408 	idx = ering->cursor;
409 	do {
410 		ent = &ering->ring[idx];
411 		if (!ent->err_mask)
412 			break;
413 		rc = map_fn(ent, arg);
414 		if (rc)
415 			break;
416 		idx = (idx - 1 + ATA_ERING_SIZE) % ATA_ERING_SIZE;
417 	} while (idx != ering->cursor);
418 
419 	return rc;
420 }
421 
422 int ata_ering_clear_cb(struct ata_ering_entry *ent, void *void_arg)
423 {
424 	ent->eflags |= ATA_EFLAG_OLD_ER;
425 	return 0;
426 }
427 
428 static void ata_ering_clear(struct ata_ering *ering)
429 {
430 	ata_ering_map(ering, ata_ering_clear_cb, NULL);
431 }
432 
433 static unsigned int ata_eh_dev_action(struct ata_device *dev)
434 {
435 	struct ata_eh_context *ehc = &dev->link->eh_context;
436 
437 	return ehc->i.action | ehc->i.dev_action[dev->devno];
438 }
439 
440 static void ata_eh_clear_action(struct ata_link *link, struct ata_device *dev,
441 				struct ata_eh_info *ehi, unsigned int action)
442 {
443 	struct ata_device *tdev;
444 
445 	if (!dev) {
446 		ehi->action &= ~action;
447 		ata_for_each_dev(tdev, link, ALL)
448 			ehi->dev_action[tdev->devno] &= ~action;
449 	} else {
450 		/* doesn't make sense for port-wide EH actions */
451 		WARN_ON(!(action & ATA_EH_PERDEV_MASK));
452 
453 		/* break ehi->action into ehi->dev_action */
454 		if (ehi->action & action) {
455 			ata_for_each_dev(tdev, link, ALL)
456 				ehi->dev_action[tdev->devno] |=
457 					ehi->action & action;
458 			ehi->action &= ~action;
459 		}
460 
461 		/* turn off the specified per-dev action */
462 		ehi->dev_action[dev->devno] &= ~action;
463 	}
464 }
465 
466 /**
467  *	ata_eh_acquire - acquire EH ownership
468  *	@ap: ATA port to acquire EH ownership for
469  *
470  *	Acquire EH ownership for @ap.  This is the basic exclusion
471  *	mechanism for ports sharing a host.  Only one port hanging off
472  *	the same host can claim the ownership of EH.
473  *
474  *	LOCKING:
475  *	EH context.
476  */
477 void ata_eh_acquire(struct ata_port *ap)
478 {
479 	mutex_lock(&ap->host->eh_mutex);
480 	WARN_ON_ONCE(ap->host->eh_owner);
481 	ap->host->eh_owner = current;
482 }
483 
484 /**
485  *	ata_eh_release - release EH ownership
486  *	@ap: ATA port to release EH ownership for
487  *
488  *	Release EH ownership for @ap if the caller.  The caller must
489  *	have acquired EH ownership using ata_eh_acquire() previously.
490  *
491  *	LOCKING:
492  *	EH context.
493  */
494 void ata_eh_release(struct ata_port *ap)
495 {
496 	WARN_ON_ONCE(ap->host->eh_owner != current);
497 	ap->host->eh_owner = NULL;
498 	mutex_unlock(&ap->host->eh_mutex);
499 }
500 
501 /**
502  *	ata_scsi_timed_out - SCSI layer time out callback
503  *	@cmd: timed out SCSI command
504  *
505  *	Handles SCSI layer timeout.  We race with normal completion of
506  *	the qc for @cmd.  If the qc is already gone, we lose and let
507  *	the scsi command finish (EH_HANDLED).  Otherwise, the qc has
508  *	timed out and EH should be invoked.  Prevent ata_qc_complete()
509  *	from finishing it by setting EH_SCHEDULED and return
510  *	EH_NOT_HANDLED.
511  *
512  *	TODO: kill this function once old EH is gone.
513  *
514  *	LOCKING:
515  *	Called from timer context
516  *
517  *	RETURNS:
518  *	EH_HANDLED or EH_NOT_HANDLED
519  */
520 enum blk_eh_timer_return ata_scsi_timed_out(struct scsi_cmnd *cmd)
521 {
522 	struct Scsi_Host *host = cmd->device->host;
523 	struct ata_port *ap = ata_shost_to_port(host);
524 	unsigned long flags;
525 	struct ata_queued_cmd *qc;
526 	enum blk_eh_timer_return ret;
527 
528 	DPRINTK("ENTER\n");
529 
530 	if (ap->ops->error_handler) {
531 		ret = BLK_EH_NOT_HANDLED;
532 		goto out;
533 	}
534 
535 	ret = BLK_EH_HANDLED;
536 	spin_lock_irqsave(ap->lock, flags);
537 	qc = ata_qc_from_tag(ap, ap->link.active_tag);
538 	if (qc) {
539 		WARN_ON(qc->scsicmd != cmd);
540 		qc->flags |= ATA_QCFLAG_EH_SCHEDULED;
541 		qc->err_mask |= AC_ERR_TIMEOUT;
542 		ret = BLK_EH_NOT_HANDLED;
543 	}
544 	spin_unlock_irqrestore(ap->lock, flags);
545 
546  out:
547 	DPRINTK("EXIT, ret=%d\n", ret);
548 	return ret;
549 }
550 
551 static void ata_eh_unload(struct ata_port *ap)
552 {
553 	struct ata_link *link;
554 	struct ata_device *dev;
555 	unsigned long flags;
556 
557 	/* Restore SControl IPM and SPD for the next driver and
558 	 * disable attached devices.
559 	 */
560 	ata_for_each_link(link, ap, PMP_FIRST) {
561 		sata_scr_write(link, SCR_CONTROL, link->saved_scontrol & 0xff0);
562 		ata_for_each_dev(dev, link, ALL)
563 			ata_dev_disable(dev);
564 	}
565 
566 	/* freeze and set UNLOADED */
567 	spin_lock_irqsave(ap->lock, flags);
568 
569 	ata_port_freeze(ap);			/* won't be thawed */
570 	ap->pflags &= ~ATA_PFLAG_EH_PENDING;	/* clear pending from freeze */
571 	ap->pflags |= ATA_PFLAG_UNLOADED;
572 
573 	spin_unlock_irqrestore(ap->lock, flags);
574 }
575 
576 /**
577  *	ata_scsi_error - SCSI layer error handler callback
578  *	@host: SCSI host on which error occurred
579  *
580  *	Handles SCSI-layer-thrown error events.
581  *
582  *	LOCKING:
583  *	Inherited from SCSI layer (none, can sleep)
584  *
585  *	RETURNS:
586  *	Zero.
587  */
588 void ata_scsi_error(struct Scsi_Host *host)
589 {
590 	struct ata_port *ap = ata_shost_to_port(host);
591 	unsigned long flags;
592 	LIST_HEAD(eh_work_q);
593 
594 	DPRINTK("ENTER\n");
595 
596 	spin_lock_irqsave(host->host_lock, flags);
597 	list_splice_init(&host->eh_cmd_q, &eh_work_q);
598 	spin_unlock_irqrestore(host->host_lock, flags);
599 
600 	ata_scsi_cmd_error_handler(host, ap, &eh_work_q);
601 
602 	/* If we timed raced normal completion and there is nothing to
603 	   recover nr_timedout == 0 why exactly are we doing error recovery ? */
604 	ata_scsi_port_error_handler(host, ap);
605 
606 	/* finish or retry handled scmd's and clean up */
607 	WARN_ON(host->host_failed || !list_empty(&eh_work_q));
608 
609 	DPRINTK("EXIT\n");
610 }
611 
612 /**
613  * ata_scsi_cmd_error_handler - error callback for a list of commands
614  * @host:	scsi host containing the port
615  * @ap:		ATA port within the host
616  * @eh_work_q:	list of commands to process
617  *
618  * process the given list of commands and return those finished to the
619  * ap->eh_done_q.  This function is the first part of the libata error
620  * handler which processes a given list of failed commands.
621  */
622 void ata_scsi_cmd_error_handler(struct Scsi_Host *host, struct ata_port *ap,
623 				struct list_head *eh_work_q)
624 {
625 	int i;
626 	unsigned long flags;
627 
628 	/* make sure sff pio task is not running */
629 	ata_sff_flush_pio_task(ap);
630 
631 	/* synchronize with host lock and sort out timeouts */
632 
633 	/* For new EH, all qcs are finished in one of three ways -
634 	 * normal completion, error completion, and SCSI timeout.
635 	 * Both completions can race against SCSI timeout.  When normal
636 	 * completion wins, the qc never reaches EH.  When error
637 	 * completion wins, the qc has ATA_QCFLAG_FAILED set.
638 	 *
639 	 * When SCSI timeout wins, things are a bit more complex.
640 	 * Normal or error completion can occur after the timeout but
641 	 * before this point.  In such cases, both types of
642 	 * completions are honored.  A scmd is determined to have
643 	 * timed out iff its associated qc is active and not failed.
644 	 */
645 	if (ap->ops->error_handler) {
646 		struct scsi_cmnd *scmd, *tmp;
647 		int nr_timedout = 0;
648 
649 		spin_lock_irqsave(ap->lock, flags);
650 
651 		/* This must occur under the ap->lock as we don't want
652 		   a polled recovery to race the real interrupt handler
653 
654 		   The lost_interrupt handler checks for any completed but
655 		   non-notified command and completes much like an IRQ handler.
656 
657 		   We then fall into the error recovery code which will treat
658 		   this as if normal completion won the race */
659 
660 		if (ap->ops->lost_interrupt)
661 			ap->ops->lost_interrupt(ap);
662 
663 		list_for_each_entry_safe(scmd, tmp, eh_work_q, eh_entry) {
664 			struct ata_queued_cmd *qc;
665 
666 			for (i = 0; i < ATA_MAX_QUEUE; i++) {
667 				qc = __ata_qc_from_tag(ap, i);
668 				if (qc->flags & ATA_QCFLAG_ACTIVE &&
669 				    qc->scsicmd == scmd)
670 					break;
671 			}
672 
673 			if (i < ATA_MAX_QUEUE) {
674 				/* the scmd has an associated qc */
675 				if (!(qc->flags & ATA_QCFLAG_FAILED)) {
676 					/* which hasn't failed yet, timeout */
677 					qc->err_mask |= AC_ERR_TIMEOUT;
678 					qc->flags |= ATA_QCFLAG_FAILED;
679 					nr_timedout++;
680 				}
681 			} else {
682 				/* Normal completion occurred after
683 				 * SCSI timeout but before this point.
684 				 * Successfully complete it.
685 				 */
686 				scmd->retries = scmd->allowed;
687 				scsi_eh_finish_cmd(scmd, &ap->eh_done_q);
688 			}
689 		}
690 
691 		/* If we have timed out qcs.  They belong to EH from
692 		 * this point but the state of the controller is
693 		 * unknown.  Freeze the port to make sure the IRQ
694 		 * handler doesn't diddle with those qcs.  This must
695 		 * be done atomically w.r.t. setting QCFLAG_FAILED.
696 		 */
697 		if (nr_timedout)
698 			__ata_port_freeze(ap);
699 
700 		spin_unlock_irqrestore(ap->lock, flags);
701 
702 		/* initialize eh_tries */
703 		ap->eh_tries = ATA_EH_MAX_TRIES;
704 	} else
705 		spin_unlock_wait(ap->lock);
706 
707 }
708 EXPORT_SYMBOL(ata_scsi_cmd_error_handler);
709 
710 /**
711  * ata_scsi_port_error_handler - recover the port after the commands
712  * @host:	SCSI host containing the port
713  * @ap:		the ATA port
714  *
715  * Handle the recovery of the port @ap after all the commands
716  * have been recovered.
717  */
718 void ata_scsi_port_error_handler(struct Scsi_Host *host, struct ata_port *ap)
719 {
720 	unsigned long flags;
721 
722 	/* invoke error handler */
723 	if (ap->ops->error_handler) {
724 		struct ata_link *link;
725 
726 		/* acquire EH ownership */
727 		ata_eh_acquire(ap);
728  repeat:
729 		/* kill fast drain timer */
730 		del_timer_sync(&ap->fastdrain_timer);
731 
732 		/* process port resume request */
733 		ata_eh_handle_port_resume(ap);
734 
735 		/* fetch & clear EH info */
736 		spin_lock_irqsave(ap->lock, flags);
737 
738 		ata_for_each_link(link, ap, HOST_FIRST) {
739 			struct ata_eh_context *ehc = &link->eh_context;
740 			struct ata_device *dev;
741 
742 			memset(&link->eh_context, 0, sizeof(link->eh_context));
743 			link->eh_context.i = link->eh_info;
744 			memset(&link->eh_info, 0, sizeof(link->eh_info));
745 
746 			ata_for_each_dev(dev, link, ENABLED) {
747 				int devno = dev->devno;
748 
749 				ehc->saved_xfer_mode[devno] = dev->xfer_mode;
750 				if (ata_ncq_enabled(dev))
751 					ehc->saved_ncq_enabled |= 1 << devno;
752 			}
753 		}
754 
755 		ap->pflags |= ATA_PFLAG_EH_IN_PROGRESS;
756 		ap->pflags &= ~ATA_PFLAG_EH_PENDING;
757 		ap->excl_link = NULL;	/* don't maintain exclusion over EH */
758 
759 		spin_unlock_irqrestore(ap->lock, flags);
760 
761 		/* invoke EH, skip if unloading or suspended */
762 		if (!(ap->pflags & (ATA_PFLAG_UNLOADING | ATA_PFLAG_SUSPENDED)))
763 			ap->ops->error_handler(ap);
764 		else {
765 			/* if unloading, commence suicide */
766 			if ((ap->pflags & ATA_PFLAG_UNLOADING) &&
767 			    !(ap->pflags & ATA_PFLAG_UNLOADED))
768 				ata_eh_unload(ap);
769 			ata_eh_finish(ap);
770 		}
771 
772 		/* process port suspend request */
773 		ata_eh_handle_port_suspend(ap);
774 
775 		/* Exception might have happened after ->error_handler
776 		 * recovered the port but before this point.  Repeat
777 		 * EH in such case.
778 		 */
779 		spin_lock_irqsave(ap->lock, flags);
780 
781 		if (ap->pflags & ATA_PFLAG_EH_PENDING) {
782 			if (--ap->eh_tries) {
783 				spin_unlock_irqrestore(ap->lock, flags);
784 				goto repeat;
785 			}
786 			ata_port_err(ap,
787 				     "EH pending after %d tries, giving up\n",
788 				     ATA_EH_MAX_TRIES);
789 			ap->pflags &= ~ATA_PFLAG_EH_PENDING;
790 		}
791 
792 		/* this run is complete, make sure EH info is clear */
793 		ata_for_each_link(link, ap, HOST_FIRST)
794 			memset(&link->eh_info, 0, sizeof(link->eh_info));
795 
796 		/* Clear host_eh_scheduled while holding ap->lock such
797 		 * that if exception occurs after this point but
798 		 * before EH completion, SCSI midlayer will
799 		 * re-initiate EH.
800 		 */
801 		host->host_eh_scheduled = 0;
802 
803 		spin_unlock_irqrestore(ap->lock, flags);
804 		ata_eh_release(ap);
805 	} else {
806 		WARN_ON(ata_qc_from_tag(ap, ap->link.active_tag) == NULL);
807 		ap->ops->eng_timeout(ap);
808 	}
809 
810 	scsi_eh_flush_done_q(&ap->eh_done_q);
811 
812 	/* clean up */
813 	spin_lock_irqsave(ap->lock, flags);
814 
815 	if (ap->pflags & ATA_PFLAG_LOADING)
816 		ap->pflags &= ~ATA_PFLAG_LOADING;
817 	else if (ap->pflags & ATA_PFLAG_SCSI_HOTPLUG)
818 		schedule_delayed_work(&ap->hotplug_task, 0);
819 
820 	if (ap->pflags & ATA_PFLAG_RECOVERED)
821 		ata_port_info(ap, "EH complete\n");
822 
823 	ap->pflags &= ~(ATA_PFLAG_SCSI_HOTPLUG | ATA_PFLAG_RECOVERED);
824 
825 	/* tell wait_eh that we're done */
826 	ap->pflags &= ~ATA_PFLAG_EH_IN_PROGRESS;
827 	wake_up_all(&ap->eh_wait_q);
828 
829 	spin_unlock_irqrestore(ap->lock, flags);
830 }
831 EXPORT_SYMBOL_GPL(ata_scsi_port_error_handler);
832 
833 /**
834  *	ata_port_wait_eh - Wait for the currently pending EH to complete
835  *	@ap: Port to wait EH for
836  *
837  *	Wait until the currently pending EH is complete.
838  *
839  *	LOCKING:
840  *	Kernel thread context (may sleep).
841  */
842 void ata_port_wait_eh(struct ata_port *ap)
843 {
844 	unsigned long flags;
845 	DEFINE_WAIT(wait);
846 
847  retry:
848 	spin_lock_irqsave(ap->lock, flags);
849 
850 	while (ap->pflags & (ATA_PFLAG_EH_PENDING | ATA_PFLAG_EH_IN_PROGRESS)) {
851 		prepare_to_wait(&ap->eh_wait_q, &wait, TASK_UNINTERRUPTIBLE);
852 		spin_unlock_irqrestore(ap->lock, flags);
853 		schedule();
854 		spin_lock_irqsave(ap->lock, flags);
855 	}
856 	finish_wait(&ap->eh_wait_q, &wait);
857 
858 	spin_unlock_irqrestore(ap->lock, flags);
859 
860 	/* make sure SCSI EH is complete */
861 	if (scsi_host_in_recovery(ap->scsi_host)) {
862 		ata_msleep(ap, 10);
863 		goto retry;
864 	}
865 }
866 
867 static int ata_eh_nr_in_flight(struct ata_port *ap)
868 {
869 	unsigned int tag;
870 	int nr = 0;
871 
872 	/* count only non-internal commands */
873 	for (tag = 0; tag < ATA_MAX_QUEUE - 1; tag++)
874 		if (ata_qc_from_tag(ap, tag))
875 			nr++;
876 
877 	return nr;
878 }
879 
880 void ata_eh_fastdrain_timerfn(unsigned long arg)
881 {
882 	struct ata_port *ap = (void *)arg;
883 	unsigned long flags;
884 	int cnt;
885 
886 	spin_lock_irqsave(ap->lock, flags);
887 
888 	cnt = ata_eh_nr_in_flight(ap);
889 
890 	/* are we done? */
891 	if (!cnt)
892 		goto out_unlock;
893 
894 	if (cnt == ap->fastdrain_cnt) {
895 		unsigned int tag;
896 
897 		/* No progress during the last interval, tag all
898 		 * in-flight qcs as timed out and freeze the port.
899 		 */
900 		for (tag = 0; tag < ATA_MAX_QUEUE - 1; tag++) {
901 			struct ata_queued_cmd *qc = ata_qc_from_tag(ap, tag);
902 			if (qc)
903 				qc->err_mask |= AC_ERR_TIMEOUT;
904 		}
905 
906 		ata_port_freeze(ap);
907 	} else {
908 		/* some qcs have finished, give it another chance */
909 		ap->fastdrain_cnt = cnt;
910 		ap->fastdrain_timer.expires =
911 			ata_deadline(jiffies, ATA_EH_FASTDRAIN_INTERVAL);
912 		add_timer(&ap->fastdrain_timer);
913 	}
914 
915  out_unlock:
916 	spin_unlock_irqrestore(ap->lock, flags);
917 }
918 
919 /**
920  *	ata_eh_set_pending - set ATA_PFLAG_EH_PENDING and activate fast drain
921  *	@ap: target ATA port
922  *	@fastdrain: activate fast drain
923  *
924  *	Set ATA_PFLAG_EH_PENDING and activate fast drain if @fastdrain
925  *	is non-zero and EH wasn't pending before.  Fast drain ensures
926  *	that EH kicks in in timely manner.
927  *
928  *	LOCKING:
929  *	spin_lock_irqsave(host lock)
930  */
931 static void ata_eh_set_pending(struct ata_port *ap, int fastdrain)
932 {
933 	int cnt;
934 
935 	/* already scheduled? */
936 	if (ap->pflags & ATA_PFLAG_EH_PENDING)
937 		return;
938 
939 	ap->pflags |= ATA_PFLAG_EH_PENDING;
940 
941 	if (!fastdrain)
942 		return;
943 
944 	/* do we have in-flight qcs? */
945 	cnt = ata_eh_nr_in_flight(ap);
946 	if (!cnt)
947 		return;
948 
949 	/* activate fast drain */
950 	ap->fastdrain_cnt = cnt;
951 	ap->fastdrain_timer.expires =
952 		ata_deadline(jiffies, ATA_EH_FASTDRAIN_INTERVAL);
953 	add_timer(&ap->fastdrain_timer);
954 }
955 
956 /**
957  *	ata_qc_schedule_eh - schedule qc for error handling
958  *	@qc: command to schedule error handling for
959  *
960  *	Schedule error handling for @qc.  EH will kick in as soon as
961  *	other commands are drained.
962  *
963  *	LOCKING:
964  *	spin_lock_irqsave(host lock)
965  */
966 void ata_qc_schedule_eh(struct ata_queued_cmd *qc)
967 {
968 	struct ata_port *ap = qc->ap;
969 	struct request_queue *q = qc->scsicmd->device->request_queue;
970 	unsigned long flags;
971 
972 	WARN_ON(!ap->ops->error_handler);
973 
974 	qc->flags |= ATA_QCFLAG_FAILED;
975 	ata_eh_set_pending(ap, 1);
976 
977 	/* The following will fail if timeout has already expired.
978 	 * ata_scsi_error() takes care of such scmds on EH entry.
979 	 * Note that ATA_QCFLAG_FAILED is unconditionally set after
980 	 * this function completes.
981 	 */
982 	spin_lock_irqsave(q->queue_lock, flags);
983 	blk_abort_request(qc->scsicmd->request);
984 	spin_unlock_irqrestore(q->queue_lock, flags);
985 }
986 
987 /**
988  *	ata_port_schedule_eh - schedule error handling without a qc
989  *	@ap: ATA port to schedule EH for
990  *
991  *	Schedule error handling for @ap.  EH will kick in as soon as
992  *	all commands are drained.
993  *
994  *	LOCKING:
995  *	spin_lock_irqsave(host lock)
996  */
997 void ata_port_schedule_eh(struct ata_port *ap)
998 {
999 	WARN_ON(!ap->ops->error_handler);
1000 
1001 	if (ap->pflags & ATA_PFLAG_INITIALIZING)
1002 		return;
1003 
1004 	ata_eh_set_pending(ap, 1);
1005 	scsi_schedule_eh(ap->scsi_host);
1006 
1007 	DPRINTK("port EH scheduled\n");
1008 }
1009 
1010 static int ata_do_link_abort(struct ata_port *ap, struct ata_link *link)
1011 {
1012 	int tag, nr_aborted = 0;
1013 
1014 	WARN_ON(!ap->ops->error_handler);
1015 
1016 	/* we're gonna abort all commands, no need for fast drain */
1017 	ata_eh_set_pending(ap, 0);
1018 
1019 	for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
1020 		struct ata_queued_cmd *qc = ata_qc_from_tag(ap, tag);
1021 
1022 		if (qc && (!link || qc->dev->link == link)) {
1023 			qc->flags |= ATA_QCFLAG_FAILED;
1024 			ata_qc_complete(qc);
1025 			nr_aborted++;
1026 		}
1027 	}
1028 
1029 	if (!nr_aborted)
1030 		ata_port_schedule_eh(ap);
1031 
1032 	return nr_aborted;
1033 }
1034 
1035 /**
1036  *	ata_link_abort - abort all qc's on the link
1037  *	@link: ATA link to abort qc's for
1038  *
1039  *	Abort all active qc's active on @link and schedule EH.
1040  *
1041  *	LOCKING:
1042  *	spin_lock_irqsave(host lock)
1043  *
1044  *	RETURNS:
1045  *	Number of aborted qc's.
1046  */
1047 int ata_link_abort(struct ata_link *link)
1048 {
1049 	return ata_do_link_abort(link->ap, link);
1050 }
1051 
1052 /**
1053  *	ata_port_abort - abort all qc's on the port
1054  *	@ap: ATA port to abort qc's for
1055  *
1056  *	Abort all active qc's of @ap and schedule EH.
1057  *
1058  *	LOCKING:
1059  *	spin_lock_irqsave(host_set lock)
1060  *
1061  *	RETURNS:
1062  *	Number of aborted qc's.
1063  */
1064 int ata_port_abort(struct ata_port *ap)
1065 {
1066 	return ata_do_link_abort(ap, NULL);
1067 }
1068 
1069 /**
1070  *	__ata_port_freeze - freeze port
1071  *	@ap: ATA port to freeze
1072  *
1073  *	This function is called when HSM violation or some other
1074  *	condition disrupts normal operation of the port.  Frozen port
1075  *	is not allowed to perform any operation until the port is
1076  *	thawed, which usually follows a successful reset.
1077  *
1078  *	ap->ops->freeze() callback can be used for freezing the port
1079  *	hardware-wise (e.g. mask interrupt and stop DMA engine).  If a
1080  *	port cannot be frozen hardware-wise, the interrupt handler
1081  *	must ack and clear interrupts unconditionally while the port
1082  *	is frozen.
1083  *
1084  *	LOCKING:
1085  *	spin_lock_irqsave(host lock)
1086  */
1087 static void __ata_port_freeze(struct ata_port *ap)
1088 {
1089 	WARN_ON(!ap->ops->error_handler);
1090 
1091 	if (ap->ops->freeze)
1092 		ap->ops->freeze(ap);
1093 
1094 	ap->pflags |= ATA_PFLAG_FROZEN;
1095 
1096 	DPRINTK("ata%u port frozen\n", ap->print_id);
1097 }
1098 
1099 /**
1100  *	ata_port_freeze - abort & freeze port
1101  *	@ap: ATA port to freeze
1102  *
1103  *	Abort and freeze @ap.  The freeze operation must be called
1104  *	first, because some hardware requires special operations
1105  *	before the taskfile registers are accessible.
1106  *
1107  *	LOCKING:
1108  *	spin_lock_irqsave(host lock)
1109  *
1110  *	RETURNS:
1111  *	Number of aborted commands.
1112  */
1113 int ata_port_freeze(struct ata_port *ap)
1114 {
1115 	int nr_aborted;
1116 
1117 	WARN_ON(!ap->ops->error_handler);
1118 
1119 	__ata_port_freeze(ap);
1120 	nr_aborted = ata_port_abort(ap);
1121 
1122 	return nr_aborted;
1123 }
1124 
1125 /**
1126  *	sata_async_notification - SATA async notification handler
1127  *	@ap: ATA port where async notification is received
1128  *
1129  *	Handler to be called when async notification via SDB FIS is
1130  *	received.  This function schedules EH if necessary.
1131  *
1132  *	LOCKING:
1133  *	spin_lock_irqsave(host lock)
1134  *
1135  *	RETURNS:
1136  *	1 if EH is scheduled, 0 otherwise.
1137  */
1138 int sata_async_notification(struct ata_port *ap)
1139 {
1140 	u32 sntf;
1141 	int rc;
1142 
1143 	if (!(ap->flags & ATA_FLAG_AN))
1144 		return 0;
1145 
1146 	rc = sata_scr_read(&ap->link, SCR_NOTIFICATION, &sntf);
1147 	if (rc == 0)
1148 		sata_scr_write(&ap->link, SCR_NOTIFICATION, sntf);
1149 
1150 	if (!sata_pmp_attached(ap) || rc) {
1151 		/* PMP is not attached or SNTF is not available */
1152 		if (!sata_pmp_attached(ap)) {
1153 			/* PMP is not attached.  Check whether ATAPI
1154 			 * AN is configured.  If so, notify media
1155 			 * change.
1156 			 */
1157 			struct ata_device *dev = ap->link.device;
1158 
1159 			if ((dev->class == ATA_DEV_ATAPI) &&
1160 			    (dev->flags & ATA_DFLAG_AN))
1161 				ata_scsi_media_change_notify(dev);
1162 			return 0;
1163 		} else {
1164 			/* PMP is attached but SNTF is not available.
1165 			 * ATAPI async media change notification is
1166 			 * not used.  The PMP must be reporting PHY
1167 			 * status change, schedule EH.
1168 			 */
1169 			ata_port_schedule_eh(ap);
1170 			return 1;
1171 		}
1172 	} else {
1173 		/* PMP is attached and SNTF is available */
1174 		struct ata_link *link;
1175 
1176 		/* check and notify ATAPI AN */
1177 		ata_for_each_link(link, ap, EDGE) {
1178 			if (!(sntf & (1 << link->pmp)))
1179 				continue;
1180 
1181 			if ((link->device->class == ATA_DEV_ATAPI) &&
1182 			    (link->device->flags & ATA_DFLAG_AN))
1183 				ata_scsi_media_change_notify(link->device);
1184 		}
1185 
1186 		/* If PMP is reporting that PHY status of some
1187 		 * downstream ports has changed, schedule EH.
1188 		 */
1189 		if (sntf & (1 << SATA_PMP_CTRL_PORT)) {
1190 			ata_port_schedule_eh(ap);
1191 			return 1;
1192 		}
1193 
1194 		return 0;
1195 	}
1196 }
1197 
1198 /**
1199  *	ata_eh_freeze_port - EH helper to freeze port
1200  *	@ap: ATA port to freeze
1201  *
1202  *	Freeze @ap.
1203  *
1204  *	LOCKING:
1205  *	None.
1206  */
1207 void ata_eh_freeze_port(struct ata_port *ap)
1208 {
1209 	unsigned long flags;
1210 
1211 	if (!ap->ops->error_handler)
1212 		return;
1213 
1214 	spin_lock_irqsave(ap->lock, flags);
1215 	__ata_port_freeze(ap);
1216 	spin_unlock_irqrestore(ap->lock, flags);
1217 }
1218 
1219 /**
1220  *	ata_port_thaw_port - EH helper to thaw port
1221  *	@ap: ATA port to thaw
1222  *
1223  *	Thaw frozen port @ap.
1224  *
1225  *	LOCKING:
1226  *	None.
1227  */
1228 void ata_eh_thaw_port(struct ata_port *ap)
1229 {
1230 	unsigned long flags;
1231 
1232 	if (!ap->ops->error_handler)
1233 		return;
1234 
1235 	spin_lock_irqsave(ap->lock, flags);
1236 
1237 	ap->pflags &= ~ATA_PFLAG_FROZEN;
1238 
1239 	if (ap->ops->thaw)
1240 		ap->ops->thaw(ap);
1241 
1242 	spin_unlock_irqrestore(ap->lock, flags);
1243 
1244 	DPRINTK("ata%u port thawed\n", ap->print_id);
1245 }
1246 
1247 static void ata_eh_scsidone(struct scsi_cmnd *scmd)
1248 {
1249 	/* nada */
1250 }
1251 
1252 static void __ata_eh_qc_complete(struct ata_queued_cmd *qc)
1253 {
1254 	struct ata_port *ap = qc->ap;
1255 	struct scsi_cmnd *scmd = qc->scsicmd;
1256 	unsigned long flags;
1257 
1258 	spin_lock_irqsave(ap->lock, flags);
1259 	qc->scsidone = ata_eh_scsidone;
1260 	__ata_qc_complete(qc);
1261 	WARN_ON(ata_tag_valid(qc->tag));
1262 	spin_unlock_irqrestore(ap->lock, flags);
1263 
1264 	scsi_eh_finish_cmd(scmd, &ap->eh_done_q);
1265 }
1266 
1267 /**
1268  *	ata_eh_qc_complete - Complete an active ATA command from EH
1269  *	@qc: Command to complete
1270  *
1271  *	Indicate to the mid and upper layers that an ATA command has
1272  *	completed.  To be used from EH.
1273  */
1274 void ata_eh_qc_complete(struct ata_queued_cmd *qc)
1275 {
1276 	struct scsi_cmnd *scmd = qc->scsicmd;
1277 	scmd->retries = scmd->allowed;
1278 	__ata_eh_qc_complete(qc);
1279 }
1280 
1281 /**
1282  *	ata_eh_qc_retry - Tell midlayer to retry an ATA command after EH
1283  *	@qc: Command to retry
1284  *
1285  *	Indicate to the mid and upper layers that an ATA command
1286  *	should be retried.  To be used from EH.
1287  *
1288  *	SCSI midlayer limits the number of retries to scmd->allowed.
1289  *	scmd->retries is decremented for commands which get retried
1290  *	due to unrelated failures (qc->err_mask is zero).
1291  */
1292 void ata_eh_qc_retry(struct ata_queued_cmd *qc)
1293 {
1294 	struct scsi_cmnd *scmd = qc->scsicmd;
1295 	if (!qc->err_mask && scmd->retries)
1296 		scmd->retries--;
1297 	__ata_eh_qc_complete(qc);
1298 }
1299 
1300 /**
1301  *	ata_dev_disable - disable ATA device
1302  *	@dev: ATA device to disable
1303  *
1304  *	Disable @dev.
1305  *
1306  *	Locking:
1307  *	EH context.
1308  */
1309 void ata_dev_disable(struct ata_device *dev)
1310 {
1311 	if (!ata_dev_enabled(dev))
1312 		return;
1313 
1314 	if (ata_msg_drv(dev->link->ap))
1315 		ata_dev_warn(dev, "disabled\n");
1316 	ata_acpi_on_disable(dev);
1317 	ata_down_xfermask_limit(dev, ATA_DNXFER_FORCE_PIO0 | ATA_DNXFER_QUIET);
1318 	dev->class++;
1319 
1320 	/* From now till the next successful probe, ering is used to
1321 	 * track probe failures.  Clear accumulated device error info.
1322 	 */
1323 	ata_ering_clear(&dev->ering);
1324 }
1325 
1326 /**
1327  *	ata_eh_detach_dev - detach ATA device
1328  *	@dev: ATA device to detach
1329  *
1330  *	Detach @dev.
1331  *
1332  *	LOCKING:
1333  *	None.
1334  */
1335 void ata_eh_detach_dev(struct ata_device *dev)
1336 {
1337 	struct ata_link *link = dev->link;
1338 	struct ata_port *ap = link->ap;
1339 	struct ata_eh_context *ehc = &link->eh_context;
1340 	unsigned long flags;
1341 
1342 	ata_dev_disable(dev);
1343 
1344 	spin_lock_irqsave(ap->lock, flags);
1345 
1346 	dev->flags &= ~ATA_DFLAG_DETACH;
1347 
1348 	if (ata_scsi_offline_dev(dev)) {
1349 		dev->flags |= ATA_DFLAG_DETACHED;
1350 		ap->pflags |= ATA_PFLAG_SCSI_HOTPLUG;
1351 	}
1352 
1353 	/* clear per-dev EH info */
1354 	ata_eh_clear_action(link, dev, &link->eh_info, ATA_EH_PERDEV_MASK);
1355 	ata_eh_clear_action(link, dev, &link->eh_context.i, ATA_EH_PERDEV_MASK);
1356 	ehc->saved_xfer_mode[dev->devno] = 0;
1357 	ehc->saved_ncq_enabled &= ~(1 << dev->devno);
1358 
1359 	spin_unlock_irqrestore(ap->lock, flags);
1360 }
1361 
1362 /**
1363  *	ata_eh_about_to_do - about to perform eh_action
1364  *	@link: target ATA link
1365  *	@dev: target ATA dev for per-dev action (can be NULL)
1366  *	@action: action about to be performed
1367  *
1368  *	Called just before performing EH actions to clear related bits
1369  *	in @link->eh_info such that eh actions are not unnecessarily
1370  *	repeated.
1371  *
1372  *	LOCKING:
1373  *	None.
1374  */
1375 void ata_eh_about_to_do(struct ata_link *link, struct ata_device *dev,
1376 			unsigned int action)
1377 {
1378 	struct ata_port *ap = link->ap;
1379 	struct ata_eh_info *ehi = &link->eh_info;
1380 	struct ata_eh_context *ehc = &link->eh_context;
1381 	unsigned long flags;
1382 
1383 	spin_lock_irqsave(ap->lock, flags);
1384 
1385 	ata_eh_clear_action(link, dev, ehi, action);
1386 
1387 	/* About to take EH action, set RECOVERED.  Ignore actions on
1388 	 * slave links as master will do them again.
1389 	 */
1390 	if (!(ehc->i.flags & ATA_EHI_QUIET) && link != ap->slave_link)
1391 		ap->pflags |= ATA_PFLAG_RECOVERED;
1392 
1393 	spin_unlock_irqrestore(ap->lock, flags);
1394 }
1395 
1396 /**
1397  *	ata_eh_done - EH action complete
1398 *	@ap: target ATA port
1399  *	@dev: target ATA dev for per-dev action (can be NULL)
1400  *	@action: action just completed
1401  *
1402  *	Called right after performing EH actions to clear related bits
1403  *	in @link->eh_context.
1404  *
1405  *	LOCKING:
1406  *	None.
1407  */
1408 void ata_eh_done(struct ata_link *link, struct ata_device *dev,
1409 		 unsigned int action)
1410 {
1411 	struct ata_eh_context *ehc = &link->eh_context;
1412 
1413 	ata_eh_clear_action(link, dev, &ehc->i, action);
1414 }
1415 
1416 /**
1417  *	ata_err_string - convert err_mask to descriptive string
1418  *	@err_mask: error mask to convert to string
1419  *
1420  *	Convert @err_mask to descriptive string.  Errors are
1421  *	prioritized according to severity and only the most severe
1422  *	error is reported.
1423  *
1424  *	LOCKING:
1425  *	None.
1426  *
1427  *	RETURNS:
1428  *	Descriptive string for @err_mask
1429  */
1430 static const char *ata_err_string(unsigned int err_mask)
1431 {
1432 	if (err_mask & AC_ERR_HOST_BUS)
1433 		return "host bus error";
1434 	if (err_mask & AC_ERR_ATA_BUS)
1435 		return "ATA bus error";
1436 	if (err_mask & AC_ERR_TIMEOUT)
1437 		return "timeout";
1438 	if (err_mask & AC_ERR_HSM)
1439 		return "HSM violation";
1440 	if (err_mask & AC_ERR_SYSTEM)
1441 		return "internal error";
1442 	if (err_mask & AC_ERR_MEDIA)
1443 		return "media error";
1444 	if (err_mask & AC_ERR_INVALID)
1445 		return "invalid argument";
1446 	if (err_mask & AC_ERR_DEV)
1447 		return "device error";
1448 	return "unknown error";
1449 }
1450 
1451 /**
1452  *	ata_read_log_page - read a specific log page
1453  *	@dev: target device
1454  *	@page: page to read
1455  *	@buf: buffer to store read page
1456  *	@sectors: number of sectors to read
1457  *
1458  *	Read log page using READ_LOG_EXT command.
1459  *
1460  *	LOCKING:
1461  *	Kernel thread context (may sleep).
1462  *
1463  *	RETURNS:
1464  *	0 on success, AC_ERR_* mask otherwise.
1465  */
1466 static unsigned int ata_read_log_page(struct ata_device *dev,
1467 				      u8 page, void *buf, unsigned int sectors)
1468 {
1469 	struct ata_taskfile tf;
1470 	unsigned int err_mask;
1471 
1472 	DPRINTK("read log page - page %d\n", page);
1473 
1474 	ata_tf_init(dev, &tf);
1475 	tf.command = ATA_CMD_READ_LOG_EXT;
1476 	tf.lbal = page;
1477 	tf.nsect = sectors;
1478 	tf.hob_nsect = sectors >> 8;
1479 	tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_LBA48 | ATA_TFLAG_DEVICE;
1480 	tf.protocol = ATA_PROT_PIO;
1481 
1482 	err_mask = ata_exec_internal(dev, &tf, NULL, DMA_FROM_DEVICE,
1483 				     buf, sectors * ATA_SECT_SIZE, 0);
1484 
1485 	DPRINTK("EXIT, err_mask=%x\n", err_mask);
1486 	return err_mask;
1487 }
1488 
1489 /**
1490  *	ata_eh_read_log_10h - Read log page 10h for NCQ error details
1491  *	@dev: Device to read log page 10h from
1492  *	@tag: Resulting tag of the failed command
1493  *	@tf: Resulting taskfile registers of the failed command
1494  *
1495  *	Read log page 10h to obtain NCQ error details and clear error
1496  *	condition.
1497  *
1498  *	LOCKING:
1499  *	Kernel thread context (may sleep).
1500  *
1501  *	RETURNS:
1502  *	0 on success, -errno otherwise.
1503  */
1504 static int ata_eh_read_log_10h(struct ata_device *dev,
1505 			       int *tag, struct ata_taskfile *tf)
1506 {
1507 	u8 *buf = dev->link->ap->sector_buf;
1508 	unsigned int err_mask;
1509 	u8 csum;
1510 	int i;
1511 
1512 	err_mask = ata_read_log_page(dev, ATA_LOG_SATA_NCQ, buf, 1);
1513 	if (err_mask)
1514 		return -EIO;
1515 
1516 	csum = 0;
1517 	for (i = 0; i < ATA_SECT_SIZE; i++)
1518 		csum += buf[i];
1519 	if (csum)
1520 		ata_dev_warn(dev, "invalid checksum 0x%x on log page 10h\n",
1521 			     csum);
1522 
1523 	if (buf[0] & 0x80)
1524 		return -ENOENT;
1525 
1526 	*tag = buf[0] & 0x1f;
1527 
1528 	tf->command = buf[2];
1529 	tf->feature = buf[3];
1530 	tf->lbal = buf[4];
1531 	tf->lbam = buf[5];
1532 	tf->lbah = buf[6];
1533 	tf->device = buf[7];
1534 	tf->hob_lbal = buf[8];
1535 	tf->hob_lbam = buf[9];
1536 	tf->hob_lbah = buf[10];
1537 	tf->nsect = buf[12];
1538 	tf->hob_nsect = buf[13];
1539 
1540 	return 0;
1541 }
1542 
1543 /**
1544  *	atapi_eh_tur - perform ATAPI TEST_UNIT_READY
1545  *	@dev: target ATAPI device
1546  *	@r_sense_key: out parameter for sense_key
1547  *
1548  *	Perform ATAPI TEST_UNIT_READY.
1549  *
1550  *	LOCKING:
1551  *	EH context (may sleep).
1552  *
1553  *	RETURNS:
1554  *	0 on success, AC_ERR_* mask on failure.
1555  */
1556 static unsigned int atapi_eh_tur(struct ata_device *dev, u8 *r_sense_key)
1557 {
1558 	u8 cdb[ATAPI_CDB_LEN] = { TEST_UNIT_READY, 0, 0, 0, 0, 0 };
1559 	struct ata_taskfile tf;
1560 	unsigned int err_mask;
1561 
1562 	ata_tf_init(dev, &tf);
1563 
1564 	tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
1565 	tf.command = ATA_CMD_PACKET;
1566 	tf.protocol = ATAPI_PROT_NODATA;
1567 
1568 	err_mask = ata_exec_internal(dev, &tf, cdb, DMA_NONE, NULL, 0, 0);
1569 	if (err_mask == AC_ERR_DEV)
1570 		*r_sense_key = tf.feature >> 4;
1571 	return err_mask;
1572 }
1573 
1574 /**
1575  *	atapi_eh_request_sense - perform ATAPI REQUEST_SENSE
1576  *	@dev: device to perform REQUEST_SENSE to
1577  *	@sense_buf: result sense data buffer (SCSI_SENSE_BUFFERSIZE bytes long)
1578  *	@dfl_sense_key: default sense key to use
1579  *
1580  *	Perform ATAPI REQUEST_SENSE after the device reported CHECK
1581  *	SENSE.  This function is EH helper.
1582  *
1583  *	LOCKING:
1584  *	Kernel thread context (may sleep).
1585  *
1586  *	RETURNS:
1587  *	0 on success, AC_ERR_* mask on failure
1588  */
1589 static unsigned int atapi_eh_request_sense(struct ata_device *dev,
1590 					   u8 *sense_buf, u8 dfl_sense_key)
1591 {
1592 	u8 cdb[ATAPI_CDB_LEN] =
1593 		{ REQUEST_SENSE, 0, 0, 0, SCSI_SENSE_BUFFERSIZE, 0 };
1594 	struct ata_port *ap = dev->link->ap;
1595 	struct ata_taskfile tf;
1596 
1597 	DPRINTK("ATAPI request sense\n");
1598 
1599 	/* FIXME: is this needed? */
1600 	memset(sense_buf, 0, SCSI_SENSE_BUFFERSIZE);
1601 
1602 	/* initialize sense_buf with the error register,
1603 	 * for the case where they are -not- overwritten
1604 	 */
1605 	sense_buf[0] = 0x70;
1606 	sense_buf[2] = dfl_sense_key;
1607 
1608 	/* some devices time out if garbage left in tf */
1609 	ata_tf_init(dev, &tf);
1610 
1611 	tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
1612 	tf.command = ATA_CMD_PACKET;
1613 
1614 	/* is it pointless to prefer PIO for "safety reasons"? */
1615 	if (ap->flags & ATA_FLAG_PIO_DMA) {
1616 		tf.protocol = ATAPI_PROT_DMA;
1617 		tf.feature |= ATAPI_PKT_DMA;
1618 	} else {
1619 		tf.protocol = ATAPI_PROT_PIO;
1620 		tf.lbam = SCSI_SENSE_BUFFERSIZE;
1621 		tf.lbah = 0;
1622 	}
1623 
1624 	return ata_exec_internal(dev, &tf, cdb, DMA_FROM_DEVICE,
1625 				 sense_buf, SCSI_SENSE_BUFFERSIZE, 0);
1626 }
1627 
1628 /**
1629  *	ata_eh_analyze_serror - analyze SError for a failed port
1630  *	@link: ATA link to analyze SError for
1631  *
1632  *	Analyze SError if available and further determine cause of
1633  *	failure.
1634  *
1635  *	LOCKING:
1636  *	None.
1637  */
1638 static void ata_eh_analyze_serror(struct ata_link *link)
1639 {
1640 	struct ata_eh_context *ehc = &link->eh_context;
1641 	u32 serror = ehc->i.serror;
1642 	unsigned int err_mask = 0, action = 0;
1643 	u32 hotplug_mask;
1644 
1645 	if (serror & (SERR_PERSISTENT | SERR_DATA)) {
1646 		err_mask |= AC_ERR_ATA_BUS;
1647 		action |= ATA_EH_RESET;
1648 	}
1649 	if (serror & SERR_PROTOCOL) {
1650 		err_mask |= AC_ERR_HSM;
1651 		action |= ATA_EH_RESET;
1652 	}
1653 	if (serror & SERR_INTERNAL) {
1654 		err_mask |= AC_ERR_SYSTEM;
1655 		action |= ATA_EH_RESET;
1656 	}
1657 
1658 	/* Determine whether a hotplug event has occurred.  Both
1659 	 * SError.N/X are considered hotplug events for enabled or
1660 	 * host links.  For disabled PMP links, only N bit is
1661 	 * considered as X bit is left at 1 for link plugging.
1662 	 */
1663 	if (link->lpm_policy > ATA_LPM_MAX_POWER)
1664 		hotplug_mask = 0;	/* hotplug doesn't work w/ LPM */
1665 	else if (!(link->flags & ATA_LFLAG_DISABLED) || ata_is_host_link(link))
1666 		hotplug_mask = SERR_PHYRDY_CHG | SERR_DEV_XCHG;
1667 	else
1668 		hotplug_mask = SERR_PHYRDY_CHG;
1669 
1670 	if (serror & hotplug_mask)
1671 		ata_ehi_hotplugged(&ehc->i);
1672 
1673 	ehc->i.err_mask |= err_mask;
1674 	ehc->i.action |= action;
1675 }
1676 
1677 /**
1678  *	ata_eh_analyze_ncq_error - analyze NCQ error
1679  *	@link: ATA link to analyze NCQ error for
1680  *
1681  *	Read log page 10h, determine the offending qc and acquire
1682  *	error status TF.  For NCQ device errors, all LLDDs have to do
1683  *	is setting AC_ERR_DEV in ehi->err_mask.  This function takes
1684  *	care of the rest.
1685  *
1686  *	LOCKING:
1687  *	Kernel thread context (may sleep).
1688  */
1689 void ata_eh_analyze_ncq_error(struct ata_link *link)
1690 {
1691 	struct ata_port *ap = link->ap;
1692 	struct ata_eh_context *ehc = &link->eh_context;
1693 	struct ata_device *dev = link->device;
1694 	struct ata_queued_cmd *qc;
1695 	struct ata_taskfile tf;
1696 	int tag, rc;
1697 
1698 	/* if frozen, we can't do much */
1699 	if (ap->pflags & ATA_PFLAG_FROZEN)
1700 		return;
1701 
1702 	/* is it NCQ device error? */
1703 	if (!link->sactive || !(ehc->i.err_mask & AC_ERR_DEV))
1704 		return;
1705 
1706 	/* has LLDD analyzed already? */
1707 	for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
1708 		qc = __ata_qc_from_tag(ap, tag);
1709 
1710 		if (!(qc->flags & ATA_QCFLAG_FAILED))
1711 			continue;
1712 
1713 		if (qc->err_mask)
1714 			return;
1715 	}
1716 
1717 	/* okay, this error is ours */
1718 	memset(&tf, 0, sizeof(tf));
1719 	rc = ata_eh_read_log_10h(dev, &tag, &tf);
1720 	if (rc) {
1721 		ata_link_err(link, "failed to read log page 10h (errno=%d)\n",
1722 			     rc);
1723 		return;
1724 	}
1725 
1726 	if (!(link->sactive & (1 << tag))) {
1727 		ata_link_err(link, "log page 10h reported inactive tag %d\n",
1728 			     tag);
1729 		return;
1730 	}
1731 
1732 	/* we've got the perpetrator, condemn it */
1733 	qc = __ata_qc_from_tag(ap, tag);
1734 	memcpy(&qc->result_tf, &tf, sizeof(tf));
1735 	qc->result_tf.flags = ATA_TFLAG_ISADDR | ATA_TFLAG_LBA | ATA_TFLAG_LBA48;
1736 	qc->err_mask |= AC_ERR_DEV | AC_ERR_NCQ;
1737 	ehc->i.err_mask &= ~AC_ERR_DEV;
1738 }
1739 
1740 /**
1741  *	ata_eh_analyze_tf - analyze taskfile of a failed qc
1742  *	@qc: qc to analyze
1743  *	@tf: Taskfile registers to analyze
1744  *
1745  *	Analyze taskfile of @qc and further determine cause of
1746  *	failure.  This function also requests ATAPI sense data if
1747  *	available.
1748  *
1749  *	LOCKING:
1750  *	Kernel thread context (may sleep).
1751  *
1752  *	RETURNS:
1753  *	Determined recovery action
1754  */
1755 static unsigned int ata_eh_analyze_tf(struct ata_queued_cmd *qc,
1756 				      const struct ata_taskfile *tf)
1757 {
1758 	unsigned int tmp, action = 0;
1759 	u8 stat = tf->command, err = tf->feature;
1760 
1761 	if ((stat & (ATA_BUSY | ATA_DRQ | ATA_DRDY)) != ATA_DRDY) {
1762 		qc->err_mask |= AC_ERR_HSM;
1763 		return ATA_EH_RESET;
1764 	}
1765 
1766 	if (stat & (ATA_ERR | ATA_DF))
1767 		qc->err_mask |= AC_ERR_DEV;
1768 	else
1769 		return 0;
1770 
1771 	switch (qc->dev->class) {
1772 	case ATA_DEV_ATA:
1773 		if (err & ATA_ICRC)
1774 			qc->err_mask |= AC_ERR_ATA_BUS;
1775 		if (err & ATA_UNC)
1776 			qc->err_mask |= AC_ERR_MEDIA;
1777 		if (err & ATA_IDNF)
1778 			qc->err_mask |= AC_ERR_INVALID;
1779 		break;
1780 
1781 	case ATA_DEV_ATAPI:
1782 		if (!(qc->ap->pflags & ATA_PFLAG_FROZEN)) {
1783 			tmp = atapi_eh_request_sense(qc->dev,
1784 						qc->scsicmd->sense_buffer,
1785 						qc->result_tf.feature >> 4);
1786 			if (!tmp) {
1787 				/* ATA_QCFLAG_SENSE_VALID is used to
1788 				 * tell atapi_qc_complete() that sense
1789 				 * data is already valid.
1790 				 *
1791 				 * TODO: interpret sense data and set
1792 				 * appropriate err_mask.
1793 				 */
1794 				qc->flags |= ATA_QCFLAG_SENSE_VALID;
1795 			} else
1796 				qc->err_mask |= tmp;
1797 		}
1798 	}
1799 
1800 	if (qc->err_mask & (AC_ERR_HSM | AC_ERR_TIMEOUT | AC_ERR_ATA_BUS))
1801 		action |= ATA_EH_RESET;
1802 
1803 	return action;
1804 }
1805 
1806 static int ata_eh_categorize_error(unsigned int eflags, unsigned int err_mask,
1807 				   int *xfer_ok)
1808 {
1809 	int base = 0;
1810 
1811 	if (!(eflags & ATA_EFLAG_DUBIOUS_XFER))
1812 		*xfer_ok = 1;
1813 
1814 	if (!*xfer_ok)
1815 		base = ATA_ECAT_DUBIOUS_NONE;
1816 
1817 	if (err_mask & AC_ERR_ATA_BUS)
1818 		return base + ATA_ECAT_ATA_BUS;
1819 
1820 	if (err_mask & AC_ERR_TIMEOUT)
1821 		return base + ATA_ECAT_TOUT_HSM;
1822 
1823 	if (eflags & ATA_EFLAG_IS_IO) {
1824 		if (err_mask & AC_ERR_HSM)
1825 			return base + ATA_ECAT_TOUT_HSM;
1826 		if ((err_mask &
1827 		     (AC_ERR_DEV|AC_ERR_MEDIA|AC_ERR_INVALID)) == AC_ERR_DEV)
1828 			return base + ATA_ECAT_UNK_DEV;
1829 	}
1830 
1831 	return 0;
1832 }
1833 
1834 struct speed_down_verdict_arg {
1835 	u64 since;
1836 	int xfer_ok;
1837 	int nr_errors[ATA_ECAT_NR];
1838 };
1839 
1840 static int speed_down_verdict_cb(struct ata_ering_entry *ent, void *void_arg)
1841 {
1842 	struct speed_down_verdict_arg *arg = void_arg;
1843 	int cat;
1844 
1845 	if ((ent->eflags & ATA_EFLAG_OLD_ER) || (ent->timestamp < arg->since))
1846 		return -1;
1847 
1848 	cat = ata_eh_categorize_error(ent->eflags, ent->err_mask,
1849 				      &arg->xfer_ok);
1850 	arg->nr_errors[cat]++;
1851 
1852 	return 0;
1853 }
1854 
1855 /**
1856  *	ata_eh_speed_down_verdict - Determine speed down verdict
1857  *	@dev: Device of interest
1858  *
1859  *	This function examines error ring of @dev and determines
1860  *	whether NCQ needs to be turned off, transfer speed should be
1861  *	stepped down, or falling back to PIO is necessary.
1862  *
1863  *	ECAT_ATA_BUS	: ATA_BUS error for any command
1864  *
1865  *	ECAT_TOUT_HSM	: TIMEOUT for any command or HSM violation for
1866  *			  IO commands
1867  *
1868  *	ECAT_UNK_DEV	: Unknown DEV error for IO commands
1869  *
1870  *	ECAT_DUBIOUS_*	: Identical to above three but occurred while
1871  *			  data transfer hasn't been verified.
1872  *
1873  *	Verdicts are
1874  *
1875  *	NCQ_OFF		: Turn off NCQ.
1876  *
1877  *	SPEED_DOWN	: Speed down transfer speed but don't fall back
1878  *			  to PIO.
1879  *
1880  *	FALLBACK_TO_PIO	: Fall back to PIO.
1881  *
1882  *	Even if multiple verdicts are returned, only one action is
1883  *	taken per error.  An action triggered by non-DUBIOUS errors
1884  *	clears ering, while one triggered by DUBIOUS_* errors doesn't.
1885  *	This is to expedite speed down decisions right after device is
1886  *	initially configured.
1887  *
1888  *	The followings are speed down rules.  #1 and #2 deal with
1889  *	DUBIOUS errors.
1890  *
1891  *	1. If more than one DUBIOUS_ATA_BUS or DUBIOUS_TOUT_HSM errors
1892  *	   occurred during last 5 mins, SPEED_DOWN and FALLBACK_TO_PIO.
1893  *
1894  *	2. If more than one DUBIOUS_TOUT_HSM or DUBIOUS_UNK_DEV errors
1895  *	   occurred during last 5 mins, NCQ_OFF.
1896  *
1897  *	3. If more than 8 ATA_BUS, TOUT_HSM or UNK_DEV errors
1898  *	   occurred during last 5 mins, FALLBACK_TO_PIO
1899  *
1900  *	4. If more than 3 TOUT_HSM or UNK_DEV errors occurred
1901  *	   during last 10 mins, NCQ_OFF.
1902  *
1903  *	5. If more than 3 ATA_BUS or TOUT_HSM errors, or more than 6
1904  *	   UNK_DEV errors occurred during last 10 mins, SPEED_DOWN.
1905  *
1906  *	LOCKING:
1907  *	Inherited from caller.
1908  *
1909  *	RETURNS:
1910  *	OR of ATA_EH_SPDN_* flags.
1911  */
1912 static unsigned int ata_eh_speed_down_verdict(struct ata_device *dev)
1913 {
1914 	const u64 j5mins = 5LLU * 60 * HZ, j10mins = 10LLU * 60 * HZ;
1915 	u64 j64 = get_jiffies_64();
1916 	struct speed_down_verdict_arg arg;
1917 	unsigned int verdict = 0;
1918 
1919 	/* scan past 5 mins of error history */
1920 	memset(&arg, 0, sizeof(arg));
1921 	arg.since = j64 - min(j64, j5mins);
1922 	ata_ering_map(&dev->ering, speed_down_verdict_cb, &arg);
1923 
1924 	if (arg.nr_errors[ATA_ECAT_DUBIOUS_ATA_BUS] +
1925 	    arg.nr_errors[ATA_ECAT_DUBIOUS_TOUT_HSM] > 1)
1926 		verdict |= ATA_EH_SPDN_SPEED_DOWN |
1927 			ATA_EH_SPDN_FALLBACK_TO_PIO | ATA_EH_SPDN_KEEP_ERRORS;
1928 
1929 	if (arg.nr_errors[ATA_ECAT_DUBIOUS_TOUT_HSM] +
1930 	    arg.nr_errors[ATA_ECAT_DUBIOUS_UNK_DEV] > 1)
1931 		verdict |= ATA_EH_SPDN_NCQ_OFF | ATA_EH_SPDN_KEEP_ERRORS;
1932 
1933 	if (arg.nr_errors[ATA_ECAT_ATA_BUS] +
1934 	    arg.nr_errors[ATA_ECAT_TOUT_HSM] +
1935 	    arg.nr_errors[ATA_ECAT_UNK_DEV] > 6)
1936 		verdict |= ATA_EH_SPDN_FALLBACK_TO_PIO;
1937 
1938 	/* scan past 10 mins of error history */
1939 	memset(&arg, 0, sizeof(arg));
1940 	arg.since = j64 - min(j64, j10mins);
1941 	ata_ering_map(&dev->ering, speed_down_verdict_cb, &arg);
1942 
1943 	if (arg.nr_errors[ATA_ECAT_TOUT_HSM] +
1944 	    arg.nr_errors[ATA_ECAT_UNK_DEV] > 3)
1945 		verdict |= ATA_EH_SPDN_NCQ_OFF;
1946 
1947 	if (arg.nr_errors[ATA_ECAT_ATA_BUS] +
1948 	    arg.nr_errors[ATA_ECAT_TOUT_HSM] > 3 ||
1949 	    arg.nr_errors[ATA_ECAT_UNK_DEV] > 6)
1950 		verdict |= ATA_EH_SPDN_SPEED_DOWN;
1951 
1952 	return verdict;
1953 }
1954 
1955 /**
1956  *	ata_eh_speed_down - record error and speed down if necessary
1957  *	@dev: Failed device
1958  *	@eflags: mask of ATA_EFLAG_* flags
1959  *	@err_mask: err_mask of the error
1960  *
1961  *	Record error and examine error history to determine whether
1962  *	adjusting transmission speed is necessary.  It also sets
1963  *	transmission limits appropriately if such adjustment is
1964  *	necessary.
1965  *
1966  *	LOCKING:
1967  *	Kernel thread context (may sleep).
1968  *
1969  *	RETURNS:
1970  *	Determined recovery action.
1971  */
1972 static unsigned int ata_eh_speed_down(struct ata_device *dev,
1973 				unsigned int eflags, unsigned int err_mask)
1974 {
1975 	struct ata_link *link = ata_dev_phys_link(dev);
1976 	int xfer_ok = 0;
1977 	unsigned int verdict;
1978 	unsigned int action = 0;
1979 
1980 	/* don't bother if Cat-0 error */
1981 	if (ata_eh_categorize_error(eflags, err_mask, &xfer_ok) == 0)
1982 		return 0;
1983 
1984 	/* record error and determine whether speed down is necessary */
1985 	ata_ering_record(&dev->ering, eflags, err_mask);
1986 	verdict = ata_eh_speed_down_verdict(dev);
1987 
1988 	/* turn off NCQ? */
1989 	if ((verdict & ATA_EH_SPDN_NCQ_OFF) &&
1990 	    (dev->flags & (ATA_DFLAG_PIO | ATA_DFLAG_NCQ |
1991 			   ATA_DFLAG_NCQ_OFF)) == ATA_DFLAG_NCQ) {
1992 		dev->flags |= ATA_DFLAG_NCQ_OFF;
1993 		ata_dev_warn(dev, "NCQ disabled due to excessive errors\n");
1994 		goto done;
1995 	}
1996 
1997 	/* speed down? */
1998 	if (verdict & ATA_EH_SPDN_SPEED_DOWN) {
1999 		/* speed down SATA link speed if possible */
2000 		if (sata_down_spd_limit(link, 0) == 0) {
2001 			action |= ATA_EH_RESET;
2002 			goto done;
2003 		}
2004 
2005 		/* lower transfer mode */
2006 		if (dev->spdn_cnt < 2) {
2007 			static const int dma_dnxfer_sel[] =
2008 				{ ATA_DNXFER_DMA, ATA_DNXFER_40C };
2009 			static const int pio_dnxfer_sel[] =
2010 				{ ATA_DNXFER_PIO, ATA_DNXFER_FORCE_PIO0 };
2011 			int sel;
2012 
2013 			if (dev->xfer_shift != ATA_SHIFT_PIO)
2014 				sel = dma_dnxfer_sel[dev->spdn_cnt];
2015 			else
2016 				sel = pio_dnxfer_sel[dev->spdn_cnt];
2017 
2018 			dev->spdn_cnt++;
2019 
2020 			if (ata_down_xfermask_limit(dev, sel) == 0) {
2021 				action |= ATA_EH_RESET;
2022 				goto done;
2023 			}
2024 		}
2025 	}
2026 
2027 	/* Fall back to PIO?  Slowing down to PIO is meaningless for
2028 	 * SATA ATA devices.  Consider it only for PATA and SATAPI.
2029 	 */
2030 	if ((verdict & ATA_EH_SPDN_FALLBACK_TO_PIO) && (dev->spdn_cnt >= 2) &&
2031 	    (link->ap->cbl != ATA_CBL_SATA || dev->class == ATA_DEV_ATAPI) &&
2032 	    (dev->xfer_shift != ATA_SHIFT_PIO)) {
2033 		if (ata_down_xfermask_limit(dev, ATA_DNXFER_FORCE_PIO) == 0) {
2034 			dev->spdn_cnt = 0;
2035 			action |= ATA_EH_RESET;
2036 			goto done;
2037 		}
2038 	}
2039 
2040 	return 0;
2041  done:
2042 	/* device has been slowed down, blow error history */
2043 	if (!(verdict & ATA_EH_SPDN_KEEP_ERRORS))
2044 		ata_ering_clear(&dev->ering);
2045 	return action;
2046 }
2047 
2048 /**
2049  *	ata_eh_link_autopsy - analyze error and determine recovery action
2050  *	@link: host link to perform autopsy on
2051  *
2052  *	Analyze why @link failed and determine which recovery actions
2053  *	are needed.  This function also sets more detailed AC_ERR_*
2054  *	values and fills sense data for ATAPI CHECK SENSE.
2055  *
2056  *	LOCKING:
2057  *	Kernel thread context (may sleep).
2058  */
2059 static void ata_eh_link_autopsy(struct ata_link *link)
2060 {
2061 	struct ata_port *ap = link->ap;
2062 	struct ata_eh_context *ehc = &link->eh_context;
2063 	struct ata_device *dev;
2064 	unsigned int all_err_mask = 0, eflags = 0;
2065 	int tag;
2066 	u32 serror;
2067 	int rc;
2068 
2069 	DPRINTK("ENTER\n");
2070 
2071 	if (ehc->i.flags & ATA_EHI_NO_AUTOPSY)
2072 		return;
2073 
2074 	/* obtain and analyze SError */
2075 	rc = sata_scr_read(link, SCR_ERROR, &serror);
2076 	if (rc == 0) {
2077 		ehc->i.serror |= serror;
2078 		ata_eh_analyze_serror(link);
2079 	} else if (rc != -EOPNOTSUPP) {
2080 		/* SError read failed, force reset and probing */
2081 		ehc->i.probe_mask |= ATA_ALL_DEVICES;
2082 		ehc->i.action |= ATA_EH_RESET;
2083 		ehc->i.err_mask |= AC_ERR_OTHER;
2084 	}
2085 
2086 	/* analyze NCQ failure */
2087 	ata_eh_analyze_ncq_error(link);
2088 
2089 	/* any real error trumps AC_ERR_OTHER */
2090 	if (ehc->i.err_mask & ~AC_ERR_OTHER)
2091 		ehc->i.err_mask &= ~AC_ERR_OTHER;
2092 
2093 	all_err_mask |= ehc->i.err_mask;
2094 
2095 	for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
2096 		struct ata_queued_cmd *qc = __ata_qc_from_tag(ap, tag);
2097 
2098 		if (!(qc->flags & ATA_QCFLAG_FAILED) ||
2099 		    ata_dev_phys_link(qc->dev) != link)
2100 			continue;
2101 
2102 		/* inherit upper level err_mask */
2103 		qc->err_mask |= ehc->i.err_mask;
2104 
2105 		/* analyze TF */
2106 		ehc->i.action |= ata_eh_analyze_tf(qc, &qc->result_tf);
2107 
2108 		/* DEV errors are probably spurious in case of ATA_BUS error */
2109 		if (qc->err_mask & AC_ERR_ATA_BUS)
2110 			qc->err_mask &= ~(AC_ERR_DEV | AC_ERR_MEDIA |
2111 					  AC_ERR_INVALID);
2112 
2113 		/* any real error trumps unknown error */
2114 		if (qc->err_mask & ~AC_ERR_OTHER)
2115 			qc->err_mask &= ~AC_ERR_OTHER;
2116 
2117 		/* SENSE_VALID trumps dev/unknown error and revalidation */
2118 		if (qc->flags & ATA_QCFLAG_SENSE_VALID)
2119 			qc->err_mask &= ~(AC_ERR_DEV | AC_ERR_OTHER);
2120 
2121 		/* determine whether the command is worth retrying */
2122 		if (qc->flags & ATA_QCFLAG_IO ||
2123 		    (!(qc->err_mask & AC_ERR_INVALID) &&
2124 		     qc->err_mask != AC_ERR_DEV))
2125 			qc->flags |= ATA_QCFLAG_RETRY;
2126 
2127 		/* accumulate error info */
2128 		ehc->i.dev = qc->dev;
2129 		all_err_mask |= qc->err_mask;
2130 		if (qc->flags & ATA_QCFLAG_IO)
2131 			eflags |= ATA_EFLAG_IS_IO;
2132 	}
2133 
2134 	/* enforce default EH actions */
2135 	if (ap->pflags & ATA_PFLAG_FROZEN ||
2136 	    all_err_mask & (AC_ERR_HSM | AC_ERR_TIMEOUT))
2137 		ehc->i.action |= ATA_EH_RESET;
2138 	else if (((eflags & ATA_EFLAG_IS_IO) && all_err_mask) ||
2139 		 (!(eflags & ATA_EFLAG_IS_IO) && (all_err_mask & ~AC_ERR_DEV)))
2140 		ehc->i.action |= ATA_EH_REVALIDATE;
2141 
2142 	/* If we have offending qcs and the associated failed device,
2143 	 * perform per-dev EH action only on the offending device.
2144 	 */
2145 	if (ehc->i.dev) {
2146 		ehc->i.dev_action[ehc->i.dev->devno] |=
2147 			ehc->i.action & ATA_EH_PERDEV_MASK;
2148 		ehc->i.action &= ~ATA_EH_PERDEV_MASK;
2149 	}
2150 
2151 	/* propagate timeout to host link */
2152 	if ((all_err_mask & AC_ERR_TIMEOUT) && !ata_is_host_link(link))
2153 		ap->link.eh_context.i.err_mask |= AC_ERR_TIMEOUT;
2154 
2155 	/* record error and consider speeding down */
2156 	dev = ehc->i.dev;
2157 	if (!dev && ((ata_link_max_devices(link) == 1 &&
2158 		      ata_dev_enabled(link->device))))
2159 	    dev = link->device;
2160 
2161 	if (dev) {
2162 		if (dev->flags & ATA_DFLAG_DUBIOUS_XFER)
2163 			eflags |= ATA_EFLAG_DUBIOUS_XFER;
2164 		ehc->i.action |= ata_eh_speed_down(dev, eflags, all_err_mask);
2165 	}
2166 
2167 	DPRINTK("EXIT\n");
2168 }
2169 
2170 /**
2171  *	ata_eh_autopsy - analyze error and determine recovery action
2172  *	@ap: host port to perform autopsy on
2173  *
2174  *	Analyze all links of @ap and determine why they failed and
2175  *	which recovery actions are needed.
2176  *
2177  *	LOCKING:
2178  *	Kernel thread context (may sleep).
2179  */
2180 void ata_eh_autopsy(struct ata_port *ap)
2181 {
2182 	struct ata_link *link;
2183 
2184 	ata_for_each_link(link, ap, EDGE)
2185 		ata_eh_link_autopsy(link);
2186 
2187 	/* Handle the frigging slave link.  Autopsy is done similarly
2188 	 * but actions and flags are transferred over to the master
2189 	 * link and handled from there.
2190 	 */
2191 	if (ap->slave_link) {
2192 		struct ata_eh_context *mehc = &ap->link.eh_context;
2193 		struct ata_eh_context *sehc = &ap->slave_link->eh_context;
2194 
2195 		/* transfer control flags from master to slave */
2196 		sehc->i.flags |= mehc->i.flags & ATA_EHI_TO_SLAVE_MASK;
2197 
2198 		/* perform autopsy on the slave link */
2199 		ata_eh_link_autopsy(ap->slave_link);
2200 
2201 		/* transfer actions from slave to master and clear slave */
2202 		ata_eh_about_to_do(ap->slave_link, NULL, ATA_EH_ALL_ACTIONS);
2203 		mehc->i.action		|= sehc->i.action;
2204 		mehc->i.dev_action[1]	|= sehc->i.dev_action[1];
2205 		mehc->i.flags		|= sehc->i.flags;
2206 		ata_eh_done(ap->slave_link, NULL, ATA_EH_ALL_ACTIONS);
2207 	}
2208 
2209 	/* Autopsy of fanout ports can affect host link autopsy.
2210 	 * Perform host link autopsy last.
2211 	 */
2212 	if (sata_pmp_attached(ap))
2213 		ata_eh_link_autopsy(&ap->link);
2214 }
2215 
2216 /**
2217  *	ata_get_cmd_descript - get description for ATA command
2218  *	@command: ATA command code to get description for
2219  *
2220  *	Return a textual description of the given command, or NULL if the
2221  *	command is not known.
2222  *
2223  *	LOCKING:
2224  *	None
2225  */
2226 const char *ata_get_cmd_descript(u8 command)
2227 {
2228 #ifdef CONFIG_ATA_VERBOSE_ERROR
2229 	static const struct
2230 	{
2231 		u8 command;
2232 		const char *text;
2233 	} cmd_descr[] = {
2234 		{ ATA_CMD_DEV_RESET,		"DEVICE RESET" },
2235 		{ ATA_CMD_CHK_POWER, 		"CHECK POWER MODE" },
2236 		{ ATA_CMD_STANDBY, 		"STANDBY" },
2237 		{ ATA_CMD_IDLE, 		"IDLE" },
2238 		{ ATA_CMD_EDD, 			"EXECUTE DEVICE DIAGNOSTIC" },
2239 		{ ATA_CMD_DOWNLOAD_MICRO,   	"DOWNLOAD MICROCODE" },
2240 		{ ATA_CMD_NOP,			"NOP" },
2241 		{ ATA_CMD_FLUSH, 		"FLUSH CACHE" },
2242 		{ ATA_CMD_FLUSH_EXT, 		"FLUSH CACHE EXT" },
2243 		{ ATA_CMD_ID_ATA,  		"IDENTIFY DEVICE" },
2244 		{ ATA_CMD_ID_ATAPI, 		"IDENTIFY PACKET DEVICE" },
2245 		{ ATA_CMD_SERVICE, 		"SERVICE" },
2246 		{ ATA_CMD_READ, 		"READ DMA" },
2247 		{ ATA_CMD_READ_EXT, 		"READ DMA EXT" },
2248 		{ ATA_CMD_READ_QUEUED, 		"READ DMA QUEUED" },
2249 		{ ATA_CMD_READ_STREAM_EXT, 	"READ STREAM EXT" },
2250 		{ ATA_CMD_READ_STREAM_DMA_EXT,  "READ STREAM DMA EXT" },
2251 		{ ATA_CMD_WRITE, 		"WRITE DMA" },
2252 		{ ATA_CMD_WRITE_EXT, 		"WRITE DMA EXT" },
2253 		{ ATA_CMD_WRITE_QUEUED, 	"WRITE DMA QUEUED EXT" },
2254 		{ ATA_CMD_WRITE_STREAM_EXT, 	"WRITE STREAM EXT" },
2255 		{ ATA_CMD_WRITE_STREAM_DMA_EXT, "WRITE STREAM DMA EXT" },
2256 		{ ATA_CMD_WRITE_FUA_EXT,	"WRITE DMA FUA EXT" },
2257 		{ ATA_CMD_WRITE_QUEUED_FUA_EXT, "WRITE DMA QUEUED FUA EXT" },
2258 		{ ATA_CMD_FPDMA_READ,		"READ FPDMA QUEUED" },
2259 		{ ATA_CMD_FPDMA_WRITE,		"WRITE FPDMA QUEUED" },
2260 		{ ATA_CMD_PIO_READ,		"READ SECTOR(S)" },
2261 		{ ATA_CMD_PIO_READ_EXT,		"READ SECTOR(S) EXT" },
2262 		{ ATA_CMD_PIO_WRITE,		"WRITE SECTOR(S)" },
2263 		{ ATA_CMD_PIO_WRITE_EXT,	"WRITE SECTOR(S) EXT" },
2264 		{ ATA_CMD_READ_MULTI,		"READ MULTIPLE" },
2265 		{ ATA_CMD_READ_MULTI_EXT,	"READ MULTIPLE EXT" },
2266 		{ ATA_CMD_WRITE_MULTI,		"WRITE MULTIPLE" },
2267 		{ ATA_CMD_WRITE_MULTI_EXT,	"WRITE MULTIPLE EXT" },
2268 		{ ATA_CMD_WRITE_MULTI_FUA_EXT, 	"WRITE MULTIPLE FUA EXT" },
2269 		{ ATA_CMD_SET_FEATURES,		"SET FEATURES" },
2270 		{ ATA_CMD_SET_MULTI,		"SET MULTIPLE MODE" },
2271 		{ ATA_CMD_VERIFY,		"READ VERIFY SECTOR(S)" },
2272 		{ ATA_CMD_VERIFY_EXT,		"READ VERIFY SECTOR(S) EXT" },
2273 		{ ATA_CMD_WRITE_UNCORR_EXT,	"WRITE UNCORRECTABLE EXT" },
2274 		{ ATA_CMD_STANDBYNOW1,		"STANDBY IMMEDIATE" },
2275 		{ ATA_CMD_IDLEIMMEDIATE,	"IDLE IMMEDIATE" },
2276 		{ ATA_CMD_SLEEP,		"SLEEP" },
2277 		{ ATA_CMD_INIT_DEV_PARAMS,	"INITIALIZE DEVICE PARAMETERS" },
2278 		{ ATA_CMD_READ_NATIVE_MAX,	"READ NATIVE MAX ADDRESS" },
2279 		{ ATA_CMD_READ_NATIVE_MAX_EXT,	"READ NATIVE MAX ADDRESS EXT" },
2280 		{ ATA_CMD_SET_MAX,		"SET MAX ADDRESS" },
2281 		{ ATA_CMD_SET_MAX_EXT,		"SET MAX ADDRESS EXT" },
2282 		{ ATA_CMD_READ_LOG_EXT,		"READ LOG EXT" },
2283 		{ ATA_CMD_WRITE_LOG_EXT,	"WRITE LOG EXT" },
2284 		{ ATA_CMD_READ_LOG_DMA_EXT,	"READ LOG DMA EXT" },
2285 		{ ATA_CMD_WRITE_LOG_DMA_EXT, 	"WRITE LOG DMA EXT" },
2286 		{ ATA_CMD_TRUSTED_RCV,		"TRUSTED RECEIVE" },
2287 		{ ATA_CMD_TRUSTED_RCV_DMA, 	"TRUSTED RECEIVE DMA" },
2288 		{ ATA_CMD_TRUSTED_SND,		"TRUSTED SEND" },
2289 		{ ATA_CMD_TRUSTED_SND_DMA, 	"TRUSTED SEND DMA" },
2290 		{ ATA_CMD_PMP_READ,		"READ BUFFER" },
2291 		{ ATA_CMD_PMP_WRITE,		"WRITE BUFFER" },
2292 		{ ATA_CMD_CONF_OVERLAY,		"DEVICE CONFIGURATION OVERLAY" },
2293 		{ ATA_CMD_SEC_SET_PASS,		"SECURITY SET PASSWORD" },
2294 		{ ATA_CMD_SEC_UNLOCK,		"SECURITY UNLOCK" },
2295 		{ ATA_CMD_SEC_ERASE_PREP,	"SECURITY ERASE PREPARE" },
2296 		{ ATA_CMD_SEC_ERASE_UNIT,	"SECURITY ERASE UNIT" },
2297 		{ ATA_CMD_SEC_FREEZE_LOCK,	"SECURITY FREEZE LOCK" },
2298 		{ ATA_CMD_SEC_DISABLE_PASS,	"SECURITY DISABLE PASSWORD" },
2299 		{ ATA_CMD_CONFIG_STREAM,	"CONFIGURE STREAM" },
2300 		{ ATA_CMD_SMART,		"SMART" },
2301 		{ ATA_CMD_MEDIA_LOCK,		"DOOR LOCK" },
2302 		{ ATA_CMD_MEDIA_UNLOCK,		"DOOR UNLOCK" },
2303 		{ ATA_CMD_DSM,			"DATA SET MANAGEMENT" },
2304 		{ ATA_CMD_CHK_MED_CRD_TYP, 	"CHECK MEDIA CARD TYPE" },
2305 		{ ATA_CMD_CFA_REQ_EXT_ERR, 	"CFA REQUEST EXTENDED ERROR" },
2306 		{ ATA_CMD_CFA_WRITE_NE,		"CFA WRITE SECTORS WITHOUT ERASE" },
2307 		{ ATA_CMD_CFA_TRANS_SECT,	"CFA TRANSLATE SECTOR" },
2308 		{ ATA_CMD_CFA_ERASE,		"CFA ERASE SECTORS" },
2309 		{ ATA_CMD_CFA_WRITE_MULT_NE, 	"CFA WRITE MULTIPLE WITHOUT ERASE" },
2310 		{ ATA_CMD_READ_LONG,		"READ LONG (with retries)" },
2311 		{ ATA_CMD_READ_LONG_ONCE,	"READ LONG (without retries)" },
2312 		{ ATA_CMD_WRITE_LONG,		"WRITE LONG (with retries)" },
2313 		{ ATA_CMD_WRITE_LONG_ONCE,	"WRITE LONG (without retries)" },
2314 		{ ATA_CMD_RESTORE,		"RECALIBRATE" },
2315 		{ 0,				NULL } /* terminate list */
2316 	};
2317 
2318 	unsigned int i;
2319 	for (i = 0; cmd_descr[i].text; i++)
2320 		if (cmd_descr[i].command == command)
2321 			return cmd_descr[i].text;
2322 #endif
2323 
2324 	return NULL;
2325 }
2326 
2327 /**
2328  *	ata_eh_link_report - report error handling to user
2329  *	@link: ATA link EH is going on
2330  *
2331  *	Report EH to user.
2332  *
2333  *	LOCKING:
2334  *	None.
2335  */
2336 static void ata_eh_link_report(struct ata_link *link)
2337 {
2338 	struct ata_port *ap = link->ap;
2339 	struct ata_eh_context *ehc = &link->eh_context;
2340 	const char *frozen, *desc;
2341 	char tries_buf[6];
2342 	int tag, nr_failed = 0;
2343 
2344 	if (ehc->i.flags & ATA_EHI_QUIET)
2345 		return;
2346 
2347 	desc = NULL;
2348 	if (ehc->i.desc[0] != '\0')
2349 		desc = ehc->i.desc;
2350 
2351 	for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
2352 		struct ata_queued_cmd *qc = __ata_qc_from_tag(ap, tag);
2353 
2354 		if (!(qc->flags & ATA_QCFLAG_FAILED) ||
2355 		    ata_dev_phys_link(qc->dev) != link ||
2356 		    ((qc->flags & ATA_QCFLAG_QUIET) &&
2357 		     qc->err_mask == AC_ERR_DEV))
2358 			continue;
2359 		if (qc->flags & ATA_QCFLAG_SENSE_VALID && !qc->err_mask)
2360 			continue;
2361 
2362 		nr_failed++;
2363 	}
2364 
2365 	if (!nr_failed && !ehc->i.err_mask)
2366 		return;
2367 
2368 	frozen = "";
2369 	if (ap->pflags & ATA_PFLAG_FROZEN)
2370 		frozen = " frozen";
2371 
2372 	memset(tries_buf, 0, sizeof(tries_buf));
2373 	if (ap->eh_tries < ATA_EH_MAX_TRIES)
2374 		snprintf(tries_buf, sizeof(tries_buf) - 1, " t%d",
2375 			 ap->eh_tries);
2376 
2377 	if (ehc->i.dev) {
2378 		ata_dev_err(ehc->i.dev, "exception Emask 0x%x "
2379 			    "SAct 0x%x SErr 0x%x action 0x%x%s%s\n",
2380 			    ehc->i.err_mask, link->sactive, ehc->i.serror,
2381 			    ehc->i.action, frozen, tries_buf);
2382 		if (desc)
2383 			ata_dev_err(ehc->i.dev, "%s\n", desc);
2384 	} else {
2385 		ata_link_err(link, "exception Emask 0x%x "
2386 			     "SAct 0x%x SErr 0x%x action 0x%x%s%s\n",
2387 			     ehc->i.err_mask, link->sactive, ehc->i.serror,
2388 			     ehc->i.action, frozen, tries_buf);
2389 		if (desc)
2390 			ata_link_err(link, "%s\n", desc);
2391 	}
2392 
2393 #ifdef CONFIG_ATA_VERBOSE_ERROR
2394 	if (ehc->i.serror)
2395 		ata_link_err(link,
2396 		  "SError: { %s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s}\n",
2397 		  ehc->i.serror & SERR_DATA_RECOVERED ? "RecovData " : "",
2398 		  ehc->i.serror & SERR_COMM_RECOVERED ? "RecovComm " : "",
2399 		  ehc->i.serror & SERR_DATA ? "UnrecovData " : "",
2400 		  ehc->i.serror & SERR_PERSISTENT ? "Persist " : "",
2401 		  ehc->i.serror & SERR_PROTOCOL ? "Proto " : "",
2402 		  ehc->i.serror & SERR_INTERNAL ? "HostInt " : "",
2403 		  ehc->i.serror & SERR_PHYRDY_CHG ? "PHYRdyChg " : "",
2404 		  ehc->i.serror & SERR_PHY_INT_ERR ? "PHYInt " : "",
2405 		  ehc->i.serror & SERR_COMM_WAKE ? "CommWake " : "",
2406 		  ehc->i.serror & SERR_10B_8B_ERR ? "10B8B " : "",
2407 		  ehc->i.serror & SERR_DISPARITY ? "Dispar " : "",
2408 		  ehc->i.serror & SERR_CRC ? "BadCRC " : "",
2409 		  ehc->i.serror & SERR_HANDSHAKE ? "Handshk " : "",
2410 		  ehc->i.serror & SERR_LINK_SEQ_ERR ? "LinkSeq " : "",
2411 		  ehc->i.serror & SERR_TRANS_ST_ERROR ? "TrStaTrns " : "",
2412 		  ehc->i.serror & SERR_UNRECOG_FIS ? "UnrecFIS " : "",
2413 		  ehc->i.serror & SERR_DEV_XCHG ? "DevExch " : "");
2414 #endif
2415 
2416 	for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
2417 		struct ata_queued_cmd *qc = __ata_qc_from_tag(ap, tag);
2418 		struct ata_taskfile *cmd = &qc->tf, *res = &qc->result_tf;
2419 		const u8 *cdb = qc->cdb;
2420 		char data_buf[20] = "";
2421 		char cdb_buf[70] = "";
2422 
2423 		if (!(qc->flags & ATA_QCFLAG_FAILED) ||
2424 		    ata_dev_phys_link(qc->dev) != link || !qc->err_mask)
2425 			continue;
2426 
2427 		if (qc->dma_dir != DMA_NONE) {
2428 			static const char *dma_str[] = {
2429 				[DMA_BIDIRECTIONAL]	= "bidi",
2430 				[DMA_TO_DEVICE]		= "out",
2431 				[DMA_FROM_DEVICE]	= "in",
2432 			};
2433 			static const char *prot_str[] = {
2434 				[ATA_PROT_PIO]		= "pio",
2435 				[ATA_PROT_DMA]		= "dma",
2436 				[ATA_PROT_NCQ]		= "ncq",
2437 				[ATAPI_PROT_PIO]	= "pio",
2438 				[ATAPI_PROT_DMA]	= "dma",
2439 			};
2440 
2441 			snprintf(data_buf, sizeof(data_buf), " %s %u %s",
2442 				 prot_str[qc->tf.protocol], qc->nbytes,
2443 				 dma_str[qc->dma_dir]);
2444 		}
2445 
2446 		if (ata_is_atapi(qc->tf.protocol)) {
2447 			if (qc->scsicmd)
2448 				scsi_print_command(qc->scsicmd);
2449 			else
2450 				snprintf(cdb_buf, sizeof(cdb_buf),
2451 				 "cdb %02x %02x %02x %02x %02x %02x %02x %02x  "
2452 				 "%02x %02x %02x %02x %02x %02x %02x %02x\n         ",
2453 				 cdb[0], cdb[1], cdb[2], cdb[3],
2454 				 cdb[4], cdb[5], cdb[6], cdb[7],
2455 				 cdb[8], cdb[9], cdb[10], cdb[11],
2456 				 cdb[12], cdb[13], cdb[14], cdb[15]);
2457 		} else {
2458 			const char *descr = ata_get_cmd_descript(cmd->command);
2459 			if (descr)
2460 				ata_dev_err(qc->dev, "failed command: %s\n",
2461 					    descr);
2462 		}
2463 
2464 		ata_dev_err(qc->dev,
2465 			"cmd %02x/%02x:%02x:%02x:%02x:%02x/%02x:%02x:%02x:%02x:%02x/%02x "
2466 			"tag %d%s\n         %s"
2467 			"res %02x/%02x:%02x:%02x:%02x:%02x/%02x:%02x:%02x:%02x:%02x/%02x "
2468 			"Emask 0x%x (%s)%s\n",
2469 			cmd->command, cmd->feature, cmd->nsect,
2470 			cmd->lbal, cmd->lbam, cmd->lbah,
2471 			cmd->hob_feature, cmd->hob_nsect,
2472 			cmd->hob_lbal, cmd->hob_lbam, cmd->hob_lbah,
2473 			cmd->device, qc->tag, data_buf, cdb_buf,
2474 			res->command, res->feature, res->nsect,
2475 			res->lbal, res->lbam, res->lbah,
2476 			res->hob_feature, res->hob_nsect,
2477 			res->hob_lbal, res->hob_lbam, res->hob_lbah,
2478 			res->device, qc->err_mask, ata_err_string(qc->err_mask),
2479 			qc->err_mask & AC_ERR_NCQ ? " <F>" : "");
2480 
2481 #ifdef CONFIG_ATA_VERBOSE_ERROR
2482 		if (res->command & (ATA_BUSY | ATA_DRDY | ATA_DF | ATA_DRQ |
2483 				    ATA_ERR)) {
2484 			if (res->command & ATA_BUSY)
2485 				ata_dev_err(qc->dev, "status: { Busy }\n");
2486 			else
2487 				ata_dev_err(qc->dev, "status: { %s%s%s%s}\n",
2488 				  res->command & ATA_DRDY ? "DRDY " : "",
2489 				  res->command & ATA_DF ? "DF " : "",
2490 				  res->command & ATA_DRQ ? "DRQ " : "",
2491 				  res->command & ATA_ERR ? "ERR " : "");
2492 		}
2493 
2494 		if (cmd->command != ATA_CMD_PACKET &&
2495 		    (res->feature & (ATA_ICRC | ATA_UNC | ATA_IDNF |
2496 				     ATA_ABORTED)))
2497 			ata_dev_err(qc->dev, "error: { %s%s%s%s}\n",
2498 			  res->feature & ATA_ICRC ? "ICRC " : "",
2499 			  res->feature & ATA_UNC ? "UNC " : "",
2500 			  res->feature & ATA_IDNF ? "IDNF " : "",
2501 			  res->feature & ATA_ABORTED ? "ABRT " : "");
2502 #endif
2503 	}
2504 }
2505 
2506 /**
2507  *	ata_eh_report - report error handling to user
2508  *	@ap: ATA port to report EH about
2509  *
2510  *	Report EH to user.
2511  *
2512  *	LOCKING:
2513  *	None.
2514  */
2515 void ata_eh_report(struct ata_port *ap)
2516 {
2517 	struct ata_link *link;
2518 
2519 	ata_for_each_link(link, ap, HOST_FIRST)
2520 		ata_eh_link_report(link);
2521 }
2522 
2523 static int ata_do_reset(struct ata_link *link, ata_reset_fn_t reset,
2524 			unsigned int *classes, unsigned long deadline,
2525 			bool clear_classes)
2526 {
2527 	struct ata_device *dev;
2528 
2529 	if (clear_classes)
2530 		ata_for_each_dev(dev, link, ALL)
2531 			classes[dev->devno] = ATA_DEV_UNKNOWN;
2532 
2533 	return reset(link, classes, deadline);
2534 }
2535 
2536 static int ata_eh_followup_srst_needed(struct ata_link *link, int rc)
2537 {
2538 	if ((link->flags & ATA_LFLAG_NO_SRST) || ata_link_offline(link))
2539 		return 0;
2540 	if (rc == -EAGAIN)
2541 		return 1;
2542 	if (sata_pmp_supported(link->ap) && ata_is_host_link(link))
2543 		return 1;
2544 	return 0;
2545 }
2546 
2547 int ata_eh_reset(struct ata_link *link, int classify,
2548 		 ata_prereset_fn_t prereset, ata_reset_fn_t softreset,
2549 		 ata_reset_fn_t hardreset, ata_postreset_fn_t postreset)
2550 {
2551 	struct ata_port *ap = link->ap;
2552 	struct ata_link *slave = ap->slave_link;
2553 	struct ata_eh_context *ehc = &link->eh_context;
2554 	struct ata_eh_context *sehc = slave ? &slave->eh_context : NULL;
2555 	unsigned int *classes = ehc->classes;
2556 	unsigned int lflags = link->flags;
2557 	int verbose = !(ehc->i.flags & ATA_EHI_QUIET);
2558 	int max_tries = 0, try = 0;
2559 	struct ata_link *failed_link;
2560 	struct ata_device *dev;
2561 	unsigned long deadline, now;
2562 	ata_reset_fn_t reset;
2563 	unsigned long flags;
2564 	u32 sstatus;
2565 	int nr_unknown, rc;
2566 
2567 	/*
2568 	 * Prepare to reset
2569 	 */
2570 	while (ata_eh_reset_timeouts[max_tries] != ULONG_MAX)
2571 		max_tries++;
2572 	if (link->flags & ATA_LFLAG_NO_HRST)
2573 		hardreset = NULL;
2574 	if (link->flags & ATA_LFLAG_NO_SRST)
2575 		softreset = NULL;
2576 
2577 	/* make sure each reset attempt is at least COOL_DOWN apart */
2578 	if (ehc->i.flags & ATA_EHI_DID_RESET) {
2579 		now = jiffies;
2580 		WARN_ON(time_after(ehc->last_reset, now));
2581 		deadline = ata_deadline(ehc->last_reset,
2582 					ATA_EH_RESET_COOL_DOWN);
2583 		if (time_before(now, deadline))
2584 			schedule_timeout_uninterruptible(deadline - now);
2585 	}
2586 
2587 	spin_lock_irqsave(ap->lock, flags);
2588 	ap->pflags |= ATA_PFLAG_RESETTING;
2589 	spin_unlock_irqrestore(ap->lock, flags);
2590 
2591 	ata_eh_about_to_do(link, NULL, ATA_EH_RESET);
2592 
2593 	ata_for_each_dev(dev, link, ALL) {
2594 		/* If we issue an SRST then an ATA drive (not ATAPI)
2595 		 * may change configuration and be in PIO0 timing. If
2596 		 * we do a hard reset (or are coming from power on)
2597 		 * this is true for ATA or ATAPI. Until we've set a
2598 		 * suitable controller mode we should not touch the
2599 		 * bus as we may be talking too fast.
2600 		 */
2601 		dev->pio_mode = XFER_PIO_0;
2602 
2603 		/* If the controller has a pio mode setup function
2604 		 * then use it to set the chipset to rights. Don't
2605 		 * touch the DMA setup as that will be dealt with when
2606 		 * configuring devices.
2607 		 */
2608 		if (ap->ops->set_piomode)
2609 			ap->ops->set_piomode(ap, dev);
2610 	}
2611 
2612 	/* prefer hardreset */
2613 	reset = NULL;
2614 	ehc->i.action &= ~ATA_EH_RESET;
2615 	if (hardreset) {
2616 		reset = hardreset;
2617 		ehc->i.action |= ATA_EH_HARDRESET;
2618 	} else if (softreset) {
2619 		reset = softreset;
2620 		ehc->i.action |= ATA_EH_SOFTRESET;
2621 	}
2622 
2623 	if (prereset) {
2624 		unsigned long deadline = ata_deadline(jiffies,
2625 						      ATA_EH_PRERESET_TIMEOUT);
2626 
2627 		if (slave) {
2628 			sehc->i.action &= ~ATA_EH_RESET;
2629 			sehc->i.action |= ehc->i.action;
2630 		}
2631 
2632 		rc = prereset(link, deadline);
2633 
2634 		/* If present, do prereset on slave link too.  Reset
2635 		 * is skipped iff both master and slave links report
2636 		 * -ENOENT or clear ATA_EH_RESET.
2637 		 */
2638 		if (slave && (rc == 0 || rc == -ENOENT)) {
2639 			int tmp;
2640 
2641 			tmp = prereset(slave, deadline);
2642 			if (tmp != -ENOENT)
2643 				rc = tmp;
2644 
2645 			ehc->i.action |= sehc->i.action;
2646 		}
2647 
2648 		if (rc) {
2649 			if (rc == -ENOENT) {
2650 				ata_link_dbg(link, "port disabled--ignoring\n");
2651 				ehc->i.action &= ~ATA_EH_RESET;
2652 
2653 				ata_for_each_dev(dev, link, ALL)
2654 					classes[dev->devno] = ATA_DEV_NONE;
2655 
2656 				rc = 0;
2657 			} else
2658 				ata_link_err(link,
2659 					     "prereset failed (errno=%d)\n",
2660 					     rc);
2661 			goto out;
2662 		}
2663 
2664 		/* prereset() might have cleared ATA_EH_RESET.  If so,
2665 		 * bang classes, thaw and return.
2666 		 */
2667 		if (reset && !(ehc->i.action & ATA_EH_RESET)) {
2668 			ata_for_each_dev(dev, link, ALL)
2669 				classes[dev->devno] = ATA_DEV_NONE;
2670 			if ((ap->pflags & ATA_PFLAG_FROZEN) &&
2671 			    ata_is_host_link(link))
2672 				ata_eh_thaw_port(ap);
2673 			rc = 0;
2674 			goto out;
2675 		}
2676 	}
2677 
2678  retry:
2679 	/*
2680 	 * Perform reset
2681 	 */
2682 	if (ata_is_host_link(link))
2683 		ata_eh_freeze_port(ap);
2684 
2685 	deadline = ata_deadline(jiffies, ata_eh_reset_timeouts[try++]);
2686 
2687 	if (reset) {
2688 		if (verbose)
2689 			ata_link_info(link, "%s resetting link\n",
2690 				      reset == softreset ? "soft" : "hard");
2691 
2692 		/* mark that this EH session started with reset */
2693 		ehc->last_reset = jiffies;
2694 		if (reset == hardreset)
2695 			ehc->i.flags |= ATA_EHI_DID_HARDRESET;
2696 		else
2697 			ehc->i.flags |= ATA_EHI_DID_SOFTRESET;
2698 
2699 		rc = ata_do_reset(link, reset, classes, deadline, true);
2700 		if (rc && rc != -EAGAIN) {
2701 			failed_link = link;
2702 			goto fail;
2703 		}
2704 
2705 		/* hardreset slave link if existent */
2706 		if (slave && reset == hardreset) {
2707 			int tmp;
2708 
2709 			if (verbose)
2710 				ata_link_info(slave, "hard resetting link\n");
2711 
2712 			ata_eh_about_to_do(slave, NULL, ATA_EH_RESET);
2713 			tmp = ata_do_reset(slave, reset, classes, deadline,
2714 					   false);
2715 			switch (tmp) {
2716 			case -EAGAIN:
2717 				rc = -EAGAIN;
2718 			case 0:
2719 				break;
2720 			default:
2721 				failed_link = slave;
2722 				rc = tmp;
2723 				goto fail;
2724 			}
2725 		}
2726 
2727 		/* perform follow-up SRST if necessary */
2728 		if (reset == hardreset &&
2729 		    ata_eh_followup_srst_needed(link, rc)) {
2730 			reset = softreset;
2731 
2732 			if (!reset) {
2733 				ata_link_err(link,
2734 	     "follow-up softreset required but no softreset available\n");
2735 				failed_link = link;
2736 				rc = -EINVAL;
2737 				goto fail;
2738 			}
2739 
2740 			ata_eh_about_to_do(link, NULL, ATA_EH_RESET);
2741 			rc = ata_do_reset(link, reset, classes, deadline, true);
2742 			if (rc) {
2743 				failed_link = link;
2744 				goto fail;
2745 			}
2746 		}
2747 	} else {
2748 		if (verbose)
2749 			ata_link_info(link,
2750 	"no reset method available, skipping reset\n");
2751 		if (!(lflags & ATA_LFLAG_ASSUME_CLASS))
2752 			lflags |= ATA_LFLAG_ASSUME_ATA;
2753 	}
2754 
2755 	/*
2756 	 * Post-reset processing
2757 	 */
2758 	ata_for_each_dev(dev, link, ALL) {
2759 		/* After the reset, the device state is PIO 0 and the
2760 		 * controller state is undefined.  Reset also wakes up
2761 		 * drives from sleeping mode.
2762 		 */
2763 		dev->pio_mode = XFER_PIO_0;
2764 		dev->flags &= ~ATA_DFLAG_SLEEPING;
2765 
2766 		if (ata_phys_link_offline(ata_dev_phys_link(dev)))
2767 			continue;
2768 
2769 		/* apply class override */
2770 		if (lflags & ATA_LFLAG_ASSUME_ATA)
2771 			classes[dev->devno] = ATA_DEV_ATA;
2772 		else if (lflags & ATA_LFLAG_ASSUME_SEMB)
2773 			classes[dev->devno] = ATA_DEV_SEMB_UNSUP;
2774 	}
2775 
2776 	/* record current link speed */
2777 	if (sata_scr_read(link, SCR_STATUS, &sstatus) == 0)
2778 		link->sata_spd = (sstatus >> 4) & 0xf;
2779 	if (slave && sata_scr_read(slave, SCR_STATUS, &sstatus) == 0)
2780 		slave->sata_spd = (sstatus >> 4) & 0xf;
2781 
2782 	/* thaw the port */
2783 	if (ata_is_host_link(link))
2784 		ata_eh_thaw_port(ap);
2785 
2786 	/* postreset() should clear hardware SError.  Although SError
2787 	 * is cleared during link resume, clearing SError here is
2788 	 * necessary as some PHYs raise hotplug events after SRST.
2789 	 * This introduces race condition where hotplug occurs between
2790 	 * reset and here.  This race is mediated by cross checking
2791 	 * link onlineness and classification result later.
2792 	 */
2793 	if (postreset) {
2794 		postreset(link, classes);
2795 		if (slave)
2796 			postreset(slave, classes);
2797 	}
2798 
2799 	/*
2800 	 * Some controllers can't be frozen very well and may set spurious
2801 	 * error conditions during reset.  Clear accumulated error
2802 	 * information and re-thaw the port if frozen.  As reset is the
2803 	 * final recovery action and we cross check link onlineness against
2804 	 * device classification later, no hotplug event is lost by this.
2805 	 */
2806 	spin_lock_irqsave(link->ap->lock, flags);
2807 	memset(&link->eh_info, 0, sizeof(link->eh_info));
2808 	if (slave)
2809 		memset(&slave->eh_info, 0, sizeof(link->eh_info));
2810 	ap->pflags &= ~ATA_PFLAG_EH_PENDING;
2811 	spin_unlock_irqrestore(link->ap->lock, flags);
2812 
2813 	if (ap->pflags & ATA_PFLAG_FROZEN)
2814 		ata_eh_thaw_port(ap);
2815 
2816 	/*
2817 	 * Make sure onlineness and classification result correspond.
2818 	 * Hotplug could have happened during reset and some
2819 	 * controllers fail to wait while a drive is spinning up after
2820 	 * being hotplugged causing misdetection.  By cross checking
2821 	 * link on/offlineness and classification result, those
2822 	 * conditions can be reliably detected and retried.
2823 	 */
2824 	nr_unknown = 0;
2825 	ata_for_each_dev(dev, link, ALL) {
2826 		if (ata_phys_link_online(ata_dev_phys_link(dev))) {
2827 			if (classes[dev->devno] == ATA_DEV_UNKNOWN) {
2828 				ata_dev_dbg(dev, "link online but device misclassified\n");
2829 				classes[dev->devno] = ATA_DEV_NONE;
2830 				nr_unknown++;
2831 			}
2832 		} else if (ata_phys_link_offline(ata_dev_phys_link(dev))) {
2833 			if (ata_class_enabled(classes[dev->devno]))
2834 				ata_dev_dbg(dev,
2835 					    "link offline, clearing class %d to NONE\n",
2836 					    classes[dev->devno]);
2837 			classes[dev->devno] = ATA_DEV_NONE;
2838 		} else if (classes[dev->devno] == ATA_DEV_UNKNOWN) {
2839 			ata_dev_dbg(dev,
2840 				    "link status unknown, clearing UNKNOWN to NONE\n");
2841 			classes[dev->devno] = ATA_DEV_NONE;
2842 		}
2843 	}
2844 
2845 	if (classify && nr_unknown) {
2846 		if (try < max_tries) {
2847 			ata_link_warn(link,
2848 				      "link online but %d devices misclassified, retrying\n",
2849 				      nr_unknown);
2850 			failed_link = link;
2851 			rc = -EAGAIN;
2852 			goto fail;
2853 		}
2854 		ata_link_warn(link,
2855 			      "link online but %d devices misclassified, "
2856 			      "device detection might fail\n", nr_unknown);
2857 	}
2858 
2859 	/* reset successful, schedule revalidation */
2860 	ata_eh_done(link, NULL, ATA_EH_RESET);
2861 	if (slave)
2862 		ata_eh_done(slave, NULL, ATA_EH_RESET);
2863 	ehc->last_reset = jiffies;		/* update to completion time */
2864 	ehc->i.action |= ATA_EH_REVALIDATE;
2865 	link->lpm_policy = ATA_LPM_UNKNOWN;	/* reset LPM state */
2866 
2867 	rc = 0;
2868  out:
2869 	/* clear hotplug flag */
2870 	ehc->i.flags &= ~ATA_EHI_HOTPLUGGED;
2871 	if (slave)
2872 		sehc->i.flags &= ~ATA_EHI_HOTPLUGGED;
2873 
2874 	spin_lock_irqsave(ap->lock, flags);
2875 	ap->pflags &= ~ATA_PFLAG_RESETTING;
2876 	spin_unlock_irqrestore(ap->lock, flags);
2877 
2878 	return rc;
2879 
2880  fail:
2881 	/* if SCR isn't accessible on a fan-out port, PMP needs to be reset */
2882 	if (!ata_is_host_link(link) &&
2883 	    sata_scr_read(link, SCR_STATUS, &sstatus))
2884 		rc = -ERESTART;
2885 
2886 	if (rc == -ERESTART || try >= max_tries) {
2887 		/*
2888 		 * Thaw host port even if reset failed, so that the port
2889 		 * can be retried on the next phy event.  This risks
2890 		 * repeated EH runs but seems to be a better tradeoff than
2891 		 * shutting down a port after a botched hotplug attempt.
2892 		 */
2893 		if (ata_is_host_link(link))
2894 			ata_eh_thaw_port(ap);
2895 		goto out;
2896 	}
2897 
2898 	now = jiffies;
2899 	if (time_before(now, deadline)) {
2900 		unsigned long delta = deadline - now;
2901 
2902 		ata_link_warn(failed_link,
2903 			"reset failed (errno=%d), retrying in %u secs\n",
2904 			rc, DIV_ROUND_UP(jiffies_to_msecs(delta), 1000));
2905 
2906 		ata_eh_release(ap);
2907 		while (delta)
2908 			delta = schedule_timeout_uninterruptible(delta);
2909 		ata_eh_acquire(ap);
2910 	}
2911 
2912 	if (try == max_tries - 1) {
2913 		sata_down_spd_limit(link, 0);
2914 		if (slave)
2915 			sata_down_spd_limit(slave, 0);
2916 	} else if (rc == -EPIPE)
2917 		sata_down_spd_limit(failed_link, 0);
2918 
2919 	if (hardreset)
2920 		reset = hardreset;
2921 	goto retry;
2922 }
2923 
2924 static inline void ata_eh_pull_park_action(struct ata_port *ap)
2925 {
2926 	struct ata_link *link;
2927 	struct ata_device *dev;
2928 	unsigned long flags;
2929 
2930 	/*
2931 	 * This function can be thought of as an extended version of
2932 	 * ata_eh_about_to_do() specially crafted to accommodate the
2933 	 * requirements of ATA_EH_PARK handling. Since the EH thread
2934 	 * does not leave the do {} while () loop in ata_eh_recover as
2935 	 * long as the timeout for a park request to *one* device on
2936 	 * the port has not expired, and since we still want to pick
2937 	 * up park requests to other devices on the same port or
2938 	 * timeout updates for the same device, we have to pull
2939 	 * ATA_EH_PARK actions from eh_info into eh_context.i
2940 	 * ourselves at the beginning of each pass over the loop.
2941 	 *
2942 	 * Additionally, all write accesses to &ap->park_req_pending
2943 	 * through INIT_COMPLETION() (see below) or complete_all()
2944 	 * (see ata_scsi_park_store()) are protected by the host lock.
2945 	 * As a result we have that park_req_pending.done is zero on
2946 	 * exit from this function, i.e. when ATA_EH_PARK actions for
2947 	 * *all* devices on port ap have been pulled into the
2948 	 * respective eh_context structs. If, and only if,
2949 	 * park_req_pending.done is non-zero by the time we reach
2950 	 * wait_for_completion_timeout(), another ATA_EH_PARK action
2951 	 * has been scheduled for at least one of the devices on port
2952 	 * ap and we have to cycle over the do {} while () loop in
2953 	 * ata_eh_recover() again.
2954 	 */
2955 
2956 	spin_lock_irqsave(ap->lock, flags);
2957 	INIT_COMPLETION(ap->park_req_pending);
2958 	ata_for_each_link(link, ap, EDGE) {
2959 		ata_for_each_dev(dev, link, ALL) {
2960 			struct ata_eh_info *ehi = &link->eh_info;
2961 
2962 			link->eh_context.i.dev_action[dev->devno] |=
2963 				ehi->dev_action[dev->devno] & ATA_EH_PARK;
2964 			ata_eh_clear_action(link, dev, ehi, ATA_EH_PARK);
2965 		}
2966 	}
2967 	spin_unlock_irqrestore(ap->lock, flags);
2968 }
2969 
2970 static void ata_eh_park_issue_cmd(struct ata_device *dev, int park)
2971 {
2972 	struct ata_eh_context *ehc = &dev->link->eh_context;
2973 	struct ata_taskfile tf;
2974 	unsigned int err_mask;
2975 
2976 	ata_tf_init(dev, &tf);
2977 	if (park) {
2978 		ehc->unloaded_mask |= 1 << dev->devno;
2979 		tf.command = ATA_CMD_IDLEIMMEDIATE;
2980 		tf.feature = 0x44;
2981 		tf.lbal = 0x4c;
2982 		tf.lbam = 0x4e;
2983 		tf.lbah = 0x55;
2984 	} else {
2985 		ehc->unloaded_mask &= ~(1 << dev->devno);
2986 		tf.command = ATA_CMD_CHK_POWER;
2987 	}
2988 
2989 	tf.flags |= ATA_TFLAG_DEVICE | ATA_TFLAG_ISADDR;
2990 	tf.protocol |= ATA_PROT_NODATA;
2991 	err_mask = ata_exec_internal(dev, &tf, NULL, DMA_NONE, NULL, 0, 0);
2992 	if (park && (err_mask || tf.lbal != 0xc4)) {
2993 		ata_dev_err(dev, "head unload failed!\n");
2994 		ehc->unloaded_mask &= ~(1 << dev->devno);
2995 	}
2996 }
2997 
2998 static int ata_eh_revalidate_and_attach(struct ata_link *link,
2999 					struct ata_device **r_failed_dev)
3000 {
3001 	struct ata_port *ap = link->ap;
3002 	struct ata_eh_context *ehc = &link->eh_context;
3003 	struct ata_device *dev;
3004 	unsigned int new_mask = 0;
3005 	unsigned long flags;
3006 	int rc = 0;
3007 
3008 	DPRINTK("ENTER\n");
3009 
3010 	/* For PATA drive side cable detection to work, IDENTIFY must
3011 	 * be done backwards such that PDIAG- is released by the slave
3012 	 * device before the master device is identified.
3013 	 */
3014 	ata_for_each_dev(dev, link, ALL_REVERSE) {
3015 		unsigned int action = ata_eh_dev_action(dev);
3016 		unsigned int readid_flags = 0;
3017 
3018 		if (ehc->i.flags & ATA_EHI_DID_RESET)
3019 			readid_flags |= ATA_READID_POSTRESET;
3020 
3021 		if ((action & ATA_EH_REVALIDATE) && ata_dev_enabled(dev)) {
3022 			WARN_ON(dev->class == ATA_DEV_PMP);
3023 
3024 			if (ata_phys_link_offline(ata_dev_phys_link(dev))) {
3025 				rc = -EIO;
3026 				goto err;
3027 			}
3028 
3029 			ata_eh_about_to_do(link, dev, ATA_EH_REVALIDATE);
3030 			rc = ata_dev_revalidate(dev, ehc->classes[dev->devno],
3031 						readid_flags);
3032 			if (rc)
3033 				goto err;
3034 
3035 			ata_eh_done(link, dev, ATA_EH_REVALIDATE);
3036 
3037 			/* Configuration may have changed, reconfigure
3038 			 * transfer mode.
3039 			 */
3040 			ehc->i.flags |= ATA_EHI_SETMODE;
3041 
3042 			/* schedule the scsi_rescan_device() here */
3043 			schedule_work(&(ap->scsi_rescan_task));
3044 		} else if (dev->class == ATA_DEV_UNKNOWN &&
3045 			   ehc->tries[dev->devno] &&
3046 			   ata_class_enabled(ehc->classes[dev->devno])) {
3047 			/* Temporarily set dev->class, it will be
3048 			 * permanently set once all configurations are
3049 			 * complete.  This is necessary because new
3050 			 * device configuration is done in two
3051 			 * separate loops.
3052 			 */
3053 			dev->class = ehc->classes[dev->devno];
3054 
3055 			if (dev->class == ATA_DEV_PMP)
3056 				rc = sata_pmp_attach(dev);
3057 			else
3058 				rc = ata_dev_read_id(dev, &dev->class,
3059 						     readid_flags, dev->id);
3060 
3061 			/* read_id might have changed class, store and reset */
3062 			ehc->classes[dev->devno] = dev->class;
3063 			dev->class = ATA_DEV_UNKNOWN;
3064 
3065 			switch (rc) {
3066 			case 0:
3067 				/* clear error info accumulated during probe */
3068 				ata_ering_clear(&dev->ering);
3069 				new_mask |= 1 << dev->devno;
3070 				break;
3071 			case -ENOENT:
3072 				/* IDENTIFY was issued to non-existent
3073 				 * device.  No need to reset.  Just
3074 				 * thaw and ignore the device.
3075 				 */
3076 				ata_eh_thaw_port(ap);
3077 				break;
3078 			default:
3079 				goto err;
3080 			}
3081 		}
3082 	}
3083 
3084 	/* PDIAG- should have been released, ask cable type if post-reset */
3085 	if ((ehc->i.flags & ATA_EHI_DID_RESET) && ata_is_host_link(link)) {
3086 		if (ap->ops->cable_detect)
3087 			ap->cbl = ap->ops->cable_detect(ap);
3088 		ata_force_cbl(ap);
3089 	}
3090 
3091 	/* Configure new devices forward such that user doesn't see
3092 	 * device detection messages backwards.
3093 	 */
3094 	ata_for_each_dev(dev, link, ALL) {
3095 		if (!(new_mask & (1 << dev->devno)))
3096 			continue;
3097 
3098 		dev->class = ehc->classes[dev->devno];
3099 
3100 		if (dev->class == ATA_DEV_PMP)
3101 			continue;
3102 
3103 		ehc->i.flags |= ATA_EHI_PRINTINFO;
3104 		rc = ata_dev_configure(dev);
3105 		ehc->i.flags &= ~ATA_EHI_PRINTINFO;
3106 		if (rc) {
3107 			dev->class = ATA_DEV_UNKNOWN;
3108 			goto err;
3109 		}
3110 
3111 		spin_lock_irqsave(ap->lock, flags);
3112 		ap->pflags |= ATA_PFLAG_SCSI_HOTPLUG;
3113 		spin_unlock_irqrestore(ap->lock, flags);
3114 
3115 		/* new device discovered, configure xfermode */
3116 		ehc->i.flags |= ATA_EHI_SETMODE;
3117 	}
3118 
3119 	return 0;
3120 
3121  err:
3122 	*r_failed_dev = dev;
3123 	DPRINTK("EXIT rc=%d\n", rc);
3124 	return rc;
3125 }
3126 
3127 /**
3128  *	ata_set_mode - Program timings and issue SET FEATURES - XFER
3129  *	@link: link on which timings will be programmed
3130  *	@r_failed_dev: out parameter for failed device
3131  *
3132  *	Set ATA device disk transfer mode (PIO3, UDMA6, etc.).  If
3133  *	ata_set_mode() fails, pointer to the failing device is
3134  *	returned in @r_failed_dev.
3135  *
3136  *	LOCKING:
3137  *	PCI/etc. bus probe sem.
3138  *
3139  *	RETURNS:
3140  *	0 on success, negative errno otherwise
3141  */
3142 int ata_set_mode(struct ata_link *link, struct ata_device **r_failed_dev)
3143 {
3144 	struct ata_port *ap = link->ap;
3145 	struct ata_device *dev;
3146 	int rc;
3147 
3148 	/* if data transfer is verified, clear DUBIOUS_XFER on ering top */
3149 	ata_for_each_dev(dev, link, ENABLED) {
3150 		if (!(dev->flags & ATA_DFLAG_DUBIOUS_XFER)) {
3151 			struct ata_ering_entry *ent;
3152 
3153 			ent = ata_ering_top(&dev->ering);
3154 			if (ent)
3155 				ent->eflags &= ~ATA_EFLAG_DUBIOUS_XFER;
3156 		}
3157 	}
3158 
3159 	/* has private set_mode? */
3160 	if (ap->ops->set_mode)
3161 		rc = ap->ops->set_mode(link, r_failed_dev);
3162 	else
3163 		rc = ata_do_set_mode(link, r_failed_dev);
3164 
3165 	/* if transfer mode has changed, set DUBIOUS_XFER on device */
3166 	ata_for_each_dev(dev, link, ENABLED) {
3167 		struct ata_eh_context *ehc = &link->eh_context;
3168 		u8 saved_xfer_mode = ehc->saved_xfer_mode[dev->devno];
3169 		u8 saved_ncq = !!(ehc->saved_ncq_enabled & (1 << dev->devno));
3170 
3171 		if (dev->xfer_mode != saved_xfer_mode ||
3172 		    ata_ncq_enabled(dev) != saved_ncq)
3173 			dev->flags |= ATA_DFLAG_DUBIOUS_XFER;
3174 	}
3175 
3176 	return rc;
3177 }
3178 
3179 /**
3180  *	atapi_eh_clear_ua - Clear ATAPI UNIT ATTENTION after reset
3181  *	@dev: ATAPI device to clear UA for
3182  *
3183  *	Resets and other operations can make an ATAPI device raise
3184  *	UNIT ATTENTION which causes the next operation to fail.  This
3185  *	function clears UA.
3186  *
3187  *	LOCKING:
3188  *	EH context (may sleep).
3189  *
3190  *	RETURNS:
3191  *	0 on success, -errno on failure.
3192  */
3193 static int atapi_eh_clear_ua(struct ata_device *dev)
3194 {
3195 	int i;
3196 
3197 	for (i = 0; i < ATA_EH_UA_TRIES; i++) {
3198 		u8 *sense_buffer = dev->link->ap->sector_buf;
3199 		u8 sense_key = 0;
3200 		unsigned int err_mask;
3201 
3202 		err_mask = atapi_eh_tur(dev, &sense_key);
3203 		if (err_mask != 0 && err_mask != AC_ERR_DEV) {
3204 			ata_dev_warn(dev,
3205 				     "TEST_UNIT_READY failed (err_mask=0x%x)\n",
3206 				     err_mask);
3207 			return -EIO;
3208 		}
3209 
3210 		if (!err_mask || sense_key != UNIT_ATTENTION)
3211 			return 0;
3212 
3213 		err_mask = atapi_eh_request_sense(dev, sense_buffer, sense_key);
3214 		if (err_mask) {
3215 			ata_dev_warn(dev, "failed to clear "
3216 				"UNIT ATTENTION (err_mask=0x%x)\n", err_mask);
3217 			return -EIO;
3218 		}
3219 	}
3220 
3221 	ata_dev_warn(dev, "UNIT ATTENTION persists after %d tries\n",
3222 		     ATA_EH_UA_TRIES);
3223 
3224 	return 0;
3225 }
3226 
3227 /**
3228  *	ata_eh_maybe_retry_flush - Retry FLUSH if necessary
3229  *	@dev: ATA device which may need FLUSH retry
3230  *
3231  *	If @dev failed FLUSH, it needs to be reported upper layer
3232  *	immediately as it means that @dev failed to remap and already
3233  *	lost at least a sector and further FLUSH retrials won't make
3234  *	any difference to the lost sector.  However, if FLUSH failed
3235  *	for other reasons, for example transmission error, FLUSH needs
3236  *	to be retried.
3237  *
3238  *	This function determines whether FLUSH failure retry is
3239  *	necessary and performs it if so.
3240  *
3241  *	RETURNS:
3242  *	0 if EH can continue, -errno if EH needs to be repeated.
3243  */
3244 static int ata_eh_maybe_retry_flush(struct ata_device *dev)
3245 {
3246 	struct ata_link *link = dev->link;
3247 	struct ata_port *ap = link->ap;
3248 	struct ata_queued_cmd *qc;
3249 	struct ata_taskfile tf;
3250 	unsigned int err_mask;
3251 	int rc = 0;
3252 
3253 	/* did flush fail for this device? */
3254 	if (!ata_tag_valid(link->active_tag))
3255 		return 0;
3256 
3257 	qc = __ata_qc_from_tag(ap, link->active_tag);
3258 	if (qc->dev != dev || (qc->tf.command != ATA_CMD_FLUSH_EXT &&
3259 			       qc->tf.command != ATA_CMD_FLUSH))
3260 		return 0;
3261 
3262 	/* if the device failed it, it should be reported to upper layers */
3263 	if (qc->err_mask & AC_ERR_DEV)
3264 		return 0;
3265 
3266 	/* flush failed for some other reason, give it another shot */
3267 	ata_tf_init(dev, &tf);
3268 
3269 	tf.command = qc->tf.command;
3270 	tf.flags |= ATA_TFLAG_DEVICE;
3271 	tf.protocol = ATA_PROT_NODATA;
3272 
3273 	ata_dev_warn(dev, "retrying FLUSH 0x%x Emask 0x%x\n",
3274 		       tf.command, qc->err_mask);
3275 
3276 	err_mask = ata_exec_internal(dev, &tf, NULL, DMA_NONE, NULL, 0, 0);
3277 	if (!err_mask) {
3278 		/*
3279 		 * FLUSH is complete but there's no way to
3280 		 * successfully complete a failed command from EH.
3281 		 * Making sure retry is allowed at least once and
3282 		 * retrying it should do the trick - whatever was in
3283 		 * the cache is already on the platter and this won't
3284 		 * cause infinite loop.
3285 		 */
3286 		qc->scsicmd->allowed = max(qc->scsicmd->allowed, 1);
3287 	} else {
3288 		ata_dev_warn(dev, "FLUSH failed Emask 0x%x\n",
3289 			       err_mask);
3290 		rc = -EIO;
3291 
3292 		/* if device failed it, report it to upper layers */
3293 		if (err_mask & AC_ERR_DEV) {
3294 			qc->err_mask |= AC_ERR_DEV;
3295 			qc->result_tf = tf;
3296 			if (!(ap->pflags & ATA_PFLAG_FROZEN))
3297 				rc = 0;
3298 		}
3299 	}
3300 	return rc;
3301 }
3302 
3303 /**
3304  *	ata_eh_set_lpm - configure SATA interface power management
3305  *	@link: link to configure power management
3306  *	@policy: the link power management policy
3307  *	@r_failed_dev: out parameter for failed device
3308  *
3309  *	Enable SATA Interface power management.  This will enable
3310  *	Device Interface Power Management (DIPM) for min_power
3311  * 	policy, and then call driver specific callbacks for
3312  *	enabling Host Initiated Power management.
3313  *
3314  *	LOCKING:
3315  *	EH context.
3316  *
3317  *	RETURNS:
3318  *	0 on success, -errno on failure.
3319  */
3320 static int ata_eh_set_lpm(struct ata_link *link, enum ata_lpm_policy policy,
3321 			  struct ata_device **r_failed_dev)
3322 {
3323 	struct ata_port *ap = ata_is_host_link(link) ? link->ap : NULL;
3324 	struct ata_eh_context *ehc = &link->eh_context;
3325 	struct ata_device *dev, *link_dev = NULL, *lpm_dev = NULL;
3326 	enum ata_lpm_policy old_policy = link->lpm_policy;
3327 	bool no_dipm = link->ap->flags & ATA_FLAG_NO_DIPM;
3328 	unsigned int hints = ATA_LPM_EMPTY | ATA_LPM_HIPM;
3329 	unsigned int err_mask;
3330 	int rc;
3331 
3332 	/* if the link or host doesn't do LPM, noop */
3333 	if ((link->flags & ATA_LFLAG_NO_LPM) || (ap && !ap->ops->set_lpm))
3334 		return 0;
3335 
3336 	/*
3337 	 * DIPM is enabled only for MIN_POWER as some devices
3338 	 * misbehave when the host NACKs transition to SLUMBER.  Order
3339 	 * device and link configurations such that the host always
3340 	 * allows DIPM requests.
3341 	 */
3342 	ata_for_each_dev(dev, link, ENABLED) {
3343 		bool hipm = ata_id_has_hipm(dev->id);
3344 		bool dipm = ata_id_has_dipm(dev->id) && !no_dipm;
3345 
3346 		/* find the first enabled and LPM enabled devices */
3347 		if (!link_dev)
3348 			link_dev = dev;
3349 
3350 		if (!lpm_dev && (hipm || dipm))
3351 			lpm_dev = dev;
3352 
3353 		hints &= ~ATA_LPM_EMPTY;
3354 		if (!hipm)
3355 			hints &= ~ATA_LPM_HIPM;
3356 
3357 		/* disable DIPM before changing link config */
3358 		if (policy != ATA_LPM_MIN_POWER && dipm) {
3359 			err_mask = ata_dev_set_feature(dev,
3360 					SETFEATURES_SATA_DISABLE, SATA_DIPM);
3361 			if (err_mask && err_mask != AC_ERR_DEV) {
3362 				ata_dev_warn(dev,
3363 					     "failed to disable DIPM, Emask 0x%x\n",
3364 					     err_mask);
3365 				rc = -EIO;
3366 				goto fail;
3367 			}
3368 		}
3369 	}
3370 
3371 	if (ap) {
3372 		rc = ap->ops->set_lpm(link, policy, hints);
3373 		if (!rc && ap->slave_link)
3374 			rc = ap->ops->set_lpm(ap->slave_link, policy, hints);
3375 	} else
3376 		rc = sata_pmp_set_lpm(link, policy, hints);
3377 
3378 	/*
3379 	 * Attribute link config failure to the first (LPM) enabled
3380 	 * device on the link.
3381 	 */
3382 	if (rc) {
3383 		if (rc == -EOPNOTSUPP) {
3384 			link->flags |= ATA_LFLAG_NO_LPM;
3385 			return 0;
3386 		}
3387 		dev = lpm_dev ? lpm_dev : link_dev;
3388 		goto fail;
3389 	}
3390 
3391 	/*
3392 	 * Low level driver acked the transition.  Issue DIPM command
3393 	 * with the new policy set.
3394 	 */
3395 	link->lpm_policy = policy;
3396 	if (ap && ap->slave_link)
3397 		ap->slave_link->lpm_policy = policy;
3398 
3399 	/* host config updated, enable DIPM if transitioning to MIN_POWER */
3400 	ata_for_each_dev(dev, link, ENABLED) {
3401 		if (policy == ATA_LPM_MIN_POWER && !no_dipm &&
3402 		    ata_id_has_dipm(dev->id)) {
3403 			err_mask = ata_dev_set_feature(dev,
3404 					SETFEATURES_SATA_ENABLE, SATA_DIPM);
3405 			if (err_mask && err_mask != AC_ERR_DEV) {
3406 				ata_dev_warn(dev,
3407 					"failed to enable DIPM, Emask 0x%x\n",
3408 					err_mask);
3409 				rc = -EIO;
3410 				goto fail;
3411 			}
3412 		}
3413 	}
3414 
3415 	return 0;
3416 
3417 fail:
3418 	/* restore the old policy */
3419 	link->lpm_policy = old_policy;
3420 	if (ap && ap->slave_link)
3421 		ap->slave_link->lpm_policy = old_policy;
3422 
3423 	/* if no device or only one more chance is left, disable LPM */
3424 	if (!dev || ehc->tries[dev->devno] <= 2) {
3425 		ata_link_warn(link, "disabling LPM on the link\n");
3426 		link->flags |= ATA_LFLAG_NO_LPM;
3427 	}
3428 	if (r_failed_dev)
3429 		*r_failed_dev = dev;
3430 	return rc;
3431 }
3432 
3433 int ata_link_nr_enabled(struct ata_link *link)
3434 {
3435 	struct ata_device *dev;
3436 	int cnt = 0;
3437 
3438 	ata_for_each_dev(dev, link, ENABLED)
3439 		cnt++;
3440 	return cnt;
3441 }
3442 
3443 static int ata_link_nr_vacant(struct ata_link *link)
3444 {
3445 	struct ata_device *dev;
3446 	int cnt = 0;
3447 
3448 	ata_for_each_dev(dev, link, ALL)
3449 		if (dev->class == ATA_DEV_UNKNOWN)
3450 			cnt++;
3451 	return cnt;
3452 }
3453 
3454 static int ata_eh_skip_recovery(struct ata_link *link)
3455 {
3456 	struct ata_port *ap = link->ap;
3457 	struct ata_eh_context *ehc = &link->eh_context;
3458 	struct ata_device *dev;
3459 
3460 	/* skip disabled links */
3461 	if (link->flags & ATA_LFLAG_DISABLED)
3462 		return 1;
3463 
3464 	/* skip if explicitly requested */
3465 	if (ehc->i.flags & ATA_EHI_NO_RECOVERY)
3466 		return 1;
3467 
3468 	/* thaw frozen port and recover failed devices */
3469 	if ((ap->pflags & ATA_PFLAG_FROZEN) || ata_link_nr_enabled(link))
3470 		return 0;
3471 
3472 	/* reset at least once if reset is requested */
3473 	if ((ehc->i.action & ATA_EH_RESET) &&
3474 	    !(ehc->i.flags & ATA_EHI_DID_RESET))
3475 		return 0;
3476 
3477 	/* skip if class codes for all vacant slots are ATA_DEV_NONE */
3478 	ata_for_each_dev(dev, link, ALL) {
3479 		if (dev->class == ATA_DEV_UNKNOWN &&
3480 		    ehc->classes[dev->devno] != ATA_DEV_NONE)
3481 			return 0;
3482 	}
3483 
3484 	return 1;
3485 }
3486 
3487 static int ata_count_probe_trials_cb(struct ata_ering_entry *ent, void *void_arg)
3488 {
3489 	u64 interval = msecs_to_jiffies(ATA_EH_PROBE_TRIAL_INTERVAL);
3490 	u64 now = get_jiffies_64();
3491 	int *trials = void_arg;
3492 
3493 	if (ent->timestamp < now - min(now, interval))
3494 		return -1;
3495 
3496 	(*trials)++;
3497 	return 0;
3498 }
3499 
3500 static int ata_eh_schedule_probe(struct ata_device *dev)
3501 {
3502 	struct ata_eh_context *ehc = &dev->link->eh_context;
3503 	struct ata_link *link = ata_dev_phys_link(dev);
3504 	int trials = 0;
3505 
3506 	if (!(ehc->i.probe_mask & (1 << dev->devno)) ||
3507 	    (ehc->did_probe_mask & (1 << dev->devno)))
3508 		return 0;
3509 
3510 	ata_eh_detach_dev(dev);
3511 	ata_dev_init(dev);
3512 	ehc->did_probe_mask |= (1 << dev->devno);
3513 	ehc->i.action |= ATA_EH_RESET;
3514 	ehc->saved_xfer_mode[dev->devno] = 0;
3515 	ehc->saved_ncq_enabled &= ~(1 << dev->devno);
3516 
3517 	/* the link maybe in a deep sleep, wake it up */
3518 	if (link->lpm_policy > ATA_LPM_MAX_POWER) {
3519 		if (ata_is_host_link(link))
3520 			link->ap->ops->set_lpm(link, ATA_LPM_MAX_POWER,
3521 					       ATA_LPM_EMPTY);
3522 		else
3523 			sata_pmp_set_lpm(link, ATA_LPM_MAX_POWER,
3524 					 ATA_LPM_EMPTY);
3525 	}
3526 
3527 	/* Record and count probe trials on the ering.  The specific
3528 	 * error mask used is irrelevant.  Because a successful device
3529 	 * detection clears the ering, this count accumulates only if
3530 	 * there are consecutive failed probes.
3531 	 *
3532 	 * If the count is equal to or higher than ATA_EH_PROBE_TRIALS
3533 	 * in the last ATA_EH_PROBE_TRIAL_INTERVAL, link speed is
3534 	 * forced to 1.5Gbps.
3535 	 *
3536 	 * This is to work around cases where failed link speed
3537 	 * negotiation results in device misdetection leading to
3538 	 * infinite DEVXCHG or PHRDY CHG events.
3539 	 */
3540 	ata_ering_record(&dev->ering, 0, AC_ERR_OTHER);
3541 	ata_ering_map(&dev->ering, ata_count_probe_trials_cb, &trials);
3542 
3543 	if (trials > ATA_EH_PROBE_TRIALS)
3544 		sata_down_spd_limit(link, 1);
3545 
3546 	return 1;
3547 }
3548 
3549 static int ata_eh_handle_dev_fail(struct ata_device *dev, int err)
3550 {
3551 	struct ata_eh_context *ehc = &dev->link->eh_context;
3552 
3553 	/* -EAGAIN from EH routine indicates retry without prejudice.
3554 	 * The requester is responsible for ensuring forward progress.
3555 	 */
3556 	if (err != -EAGAIN)
3557 		ehc->tries[dev->devno]--;
3558 
3559 	switch (err) {
3560 	case -ENODEV:
3561 		/* device missing or wrong IDENTIFY data, schedule probing */
3562 		ehc->i.probe_mask |= (1 << dev->devno);
3563 	case -EINVAL:
3564 		/* give it just one more chance */
3565 		ehc->tries[dev->devno] = min(ehc->tries[dev->devno], 1);
3566 	case -EIO:
3567 		if (ehc->tries[dev->devno] == 1) {
3568 			/* This is the last chance, better to slow
3569 			 * down than lose it.
3570 			 */
3571 			sata_down_spd_limit(ata_dev_phys_link(dev), 0);
3572 			if (dev->pio_mode > XFER_PIO_0)
3573 				ata_down_xfermask_limit(dev, ATA_DNXFER_PIO);
3574 		}
3575 	}
3576 
3577 	if (ata_dev_enabled(dev) && !ehc->tries[dev->devno]) {
3578 		/* disable device if it has used up all its chances */
3579 		ata_dev_disable(dev);
3580 
3581 		/* detach if offline */
3582 		if (ata_phys_link_offline(ata_dev_phys_link(dev)))
3583 			ata_eh_detach_dev(dev);
3584 
3585 		/* schedule probe if necessary */
3586 		if (ata_eh_schedule_probe(dev)) {
3587 			ehc->tries[dev->devno] = ATA_EH_DEV_TRIES;
3588 			memset(ehc->cmd_timeout_idx[dev->devno], 0,
3589 			       sizeof(ehc->cmd_timeout_idx[dev->devno]));
3590 		}
3591 
3592 		return 1;
3593 	} else {
3594 		ehc->i.action |= ATA_EH_RESET;
3595 		return 0;
3596 	}
3597 }
3598 
3599 /**
3600  *	ata_eh_recover - recover host port after error
3601  *	@ap: host port to recover
3602  *	@prereset: prereset method (can be NULL)
3603  *	@softreset: softreset method (can be NULL)
3604  *	@hardreset: hardreset method (can be NULL)
3605  *	@postreset: postreset method (can be NULL)
3606  *	@r_failed_link: out parameter for failed link
3607  *
3608  *	This is the alpha and omega, eum and yang, heart and soul of
3609  *	libata exception handling.  On entry, actions required to
3610  *	recover each link and hotplug requests are recorded in the
3611  *	link's eh_context.  This function executes all the operations
3612  *	with appropriate retrials and fallbacks to resurrect failed
3613  *	devices, detach goners and greet newcomers.
3614  *
3615  *	LOCKING:
3616  *	Kernel thread context (may sleep).
3617  *
3618  *	RETURNS:
3619  *	0 on success, -errno on failure.
3620  */
3621 int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
3622 		   ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
3623 		   ata_postreset_fn_t postreset,
3624 		   struct ata_link **r_failed_link)
3625 {
3626 	struct ata_link *link;
3627 	struct ata_device *dev;
3628 	int rc, nr_fails;
3629 	unsigned long flags, deadline;
3630 
3631 	DPRINTK("ENTER\n");
3632 
3633 	/* prep for recovery */
3634 	ata_for_each_link(link, ap, EDGE) {
3635 		struct ata_eh_context *ehc = &link->eh_context;
3636 
3637 		/* re-enable link? */
3638 		if (ehc->i.action & ATA_EH_ENABLE_LINK) {
3639 			ata_eh_about_to_do(link, NULL, ATA_EH_ENABLE_LINK);
3640 			spin_lock_irqsave(ap->lock, flags);
3641 			link->flags &= ~ATA_LFLAG_DISABLED;
3642 			spin_unlock_irqrestore(ap->lock, flags);
3643 			ata_eh_done(link, NULL, ATA_EH_ENABLE_LINK);
3644 		}
3645 
3646 		ata_for_each_dev(dev, link, ALL) {
3647 			if (link->flags & ATA_LFLAG_NO_RETRY)
3648 				ehc->tries[dev->devno] = 1;
3649 			else
3650 				ehc->tries[dev->devno] = ATA_EH_DEV_TRIES;
3651 
3652 			/* collect port action mask recorded in dev actions */
3653 			ehc->i.action |= ehc->i.dev_action[dev->devno] &
3654 					 ~ATA_EH_PERDEV_MASK;
3655 			ehc->i.dev_action[dev->devno] &= ATA_EH_PERDEV_MASK;
3656 
3657 			/* process hotplug request */
3658 			if (dev->flags & ATA_DFLAG_DETACH)
3659 				ata_eh_detach_dev(dev);
3660 
3661 			/* schedule probe if necessary */
3662 			if (!ata_dev_enabled(dev))
3663 				ata_eh_schedule_probe(dev);
3664 		}
3665 	}
3666 
3667  retry:
3668 	rc = 0;
3669 
3670 	/* if UNLOADING, finish immediately */
3671 	if (ap->pflags & ATA_PFLAG_UNLOADING)
3672 		goto out;
3673 
3674 	/* prep for EH */
3675 	ata_for_each_link(link, ap, EDGE) {
3676 		struct ata_eh_context *ehc = &link->eh_context;
3677 
3678 		/* skip EH if possible. */
3679 		if (ata_eh_skip_recovery(link))
3680 			ehc->i.action = 0;
3681 
3682 		ata_for_each_dev(dev, link, ALL)
3683 			ehc->classes[dev->devno] = ATA_DEV_UNKNOWN;
3684 	}
3685 
3686 	/* reset */
3687 	ata_for_each_link(link, ap, EDGE) {
3688 		struct ata_eh_context *ehc = &link->eh_context;
3689 
3690 		if (!(ehc->i.action & ATA_EH_RESET))
3691 			continue;
3692 
3693 		rc = ata_eh_reset(link, ata_link_nr_vacant(link),
3694 				  prereset, softreset, hardreset, postreset);
3695 		if (rc) {
3696 			ata_link_err(link, "reset failed, giving up\n");
3697 			goto out;
3698 		}
3699 	}
3700 
3701 	do {
3702 		unsigned long now;
3703 
3704 		/*
3705 		 * clears ATA_EH_PARK in eh_info and resets
3706 		 * ap->park_req_pending
3707 		 */
3708 		ata_eh_pull_park_action(ap);
3709 
3710 		deadline = jiffies;
3711 		ata_for_each_link(link, ap, EDGE) {
3712 			ata_for_each_dev(dev, link, ALL) {
3713 				struct ata_eh_context *ehc = &link->eh_context;
3714 				unsigned long tmp;
3715 
3716 				if (dev->class != ATA_DEV_ATA)
3717 					continue;
3718 				if (!(ehc->i.dev_action[dev->devno] &
3719 				      ATA_EH_PARK))
3720 					continue;
3721 				tmp = dev->unpark_deadline;
3722 				if (time_before(deadline, tmp))
3723 					deadline = tmp;
3724 				else if (time_before_eq(tmp, jiffies))
3725 					continue;
3726 				if (ehc->unloaded_mask & (1 << dev->devno))
3727 					continue;
3728 
3729 				ata_eh_park_issue_cmd(dev, 1);
3730 			}
3731 		}
3732 
3733 		now = jiffies;
3734 		if (time_before_eq(deadline, now))
3735 			break;
3736 
3737 		ata_eh_release(ap);
3738 		deadline = wait_for_completion_timeout(&ap->park_req_pending,
3739 						       deadline - now);
3740 		ata_eh_acquire(ap);
3741 	} while (deadline);
3742 	ata_for_each_link(link, ap, EDGE) {
3743 		ata_for_each_dev(dev, link, ALL) {
3744 			if (!(link->eh_context.unloaded_mask &
3745 			      (1 << dev->devno)))
3746 				continue;
3747 
3748 			ata_eh_park_issue_cmd(dev, 0);
3749 			ata_eh_done(link, dev, ATA_EH_PARK);
3750 		}
3751 	}
3752 
3753 	/* the rest */
3754 	nr_fails = 0;
3755 	ata_for_each_link(link, ap, PMP_FIRST) {
3756 		struct ata_eh_context *ehc = &link->eh_context;
3757 
3758 		if (sata_pmp_attached(ap) && ata_is_host_link(link))
3759 			goto config_lpm;
3760 
3761 		/* revalidate existing devices and attach new ones */
3762 		rc = ata_eh_revalidate_and_attach(link, &dev);
3763 		if (rc)
3764 			goto rest_fail;
3765 
3766 		/* if PMP got attached, return, pmp EH will take care of it */
3767 		if (link->device->class == ATA_DEV_PMP) {
3768 			ehc->i.action = 0;
3769 			return 0;
3770 		}
3771 
3772 		/* configure transfer mode if necessary */
3773 		if (ehc->i.flags & ATA_EHI_SETMODE) {
3774 			rc = ata_set_mode(link, &dev);
3775 			if (rc)
3776 				goto rest_fail;
3777 			ehc->i.flags &= ~ATA_EHI_SETMODE;
3778 		}
3779 
3780 		/* If reset has been issued, clear UA to avoid
3781 		 * disrupting the current users of the device.
3782 		 */
3783 		if (ehc->i.flags & ATA_EHI_DID_RESET) {
3784 			ata_for_each_dev(dev, link, ALL) {
3785 				if (dev->class != ATA_DEV_ATAPI)
3786 					continue;
3787 				rc = atapi_eh_clear_ua(dev);
3788 				if (rc)
3789 					goto rest_fail;
3790 			}
3791 		}
3792 
3793 		/* retry flush if necessary */
3794 		ata_for_each_dev(dev, link, ALL) {
3795 			if (dev->class != ATA_DEV_ATA)
3796 				continue;
3797 			rc = ata_eh_maybe_retry_flush(dev);
3798 			if (rc)
3799 				goto rest_fail;
3800 		}
3801 
3802 	config_lpm:
3803 		/* configure link power saving */
3804 		if (link->lpm_policy != ap->target_lpm_policy) {
3805 			rc = ata_eh_set_lpm(link, ap->target_lpm_policy, &dev);
3806 			if (rc)
3807 				goto rest_fail;
3808 		}
3809 
3810 		/* this link is okay now */
3811 		ehc->i.flags = 0;
3812 		continue;
3813 
3814 	rest_fail:
3815 		nr_fails++;
3816 		if (dev)
3817 			ata_eh_handle_dev_fail(dev, rc);
3818 
3819 		if (ap->pflags & ATA_PFLAG_FROZEN) {
3820 			/* PMP reset requires working host port.
3821 			 * Can't retry if it's frozen.
3822 			 */
3823 			if (sata_pmp_attached(ap))
3824 				goto out;
3825 			break;
3826 		}
3827 	}
3828 
3829 	if (nr_fails)
3830 		goto retry;
3831 
3832  out:
3833 	if (rc && r_failed_link)
3834 		*r_failed_link = link;
3835 
3836 	DPRINTK("EXIT, rc=%d\n", rc);
3837 	return rc;
3838 }
3839 
3840 /**
3841  *	ata_eh_finish - finish up EH
3842  *	@ap: host port to finish EH for
3843  *
3844  *	Recovery is complete.  Clean up EH states and retry or finish
3845  *	failed qcs.
3846  *
3847  *	LOCKING:
3848  *	None.
3849  */
3850 void ata_eh_finish(struct ata_port *ap)
3851 {
3852 	int tag;
3853 
3854 	/* retry or finish qcs */
3855 	for (tag = 0; tag < ATA_MAX_QUEUE; tag++) {
3856 		struct ata_queued_cmd *qc = __ata_qc_from_tag(ap, tag);
3857 
3858 		if (!(qc->flags & ATA_QCFLAG_FAILED))
3859 			continue;
3860 
3861 		if (qc->err_mask) {
3862 			/* FIXME: Once EH migration is complete,
3863 			 * generate sense data in this function,
3864 			 * considering both err_mask and tf.
3865 			 */
3866 			if (qc->flags & ATA_QCFLAG_RETRY)
3867 				ata_eh_qc_retry(qc);
3868 			else
3869 				ata_eh_qc_complete(qc);
3870 		} else {
3871 			if (qc->flags & ATA_QCFLAG_SENSE_VALID) {
3872 				ata_eh_qc_complete(qc);
3873 			} else {
3874 				/* feed zero TF to sense generation */
3875 				memset(&qc->result_tf, 0, sizeof(qc->result_tf));
3876 				ata_eh_qc_retry(qc);
3877 			}
3878 		}
3879 	}
3880 
3881 	/* make sure nr_active_links is zero after EH */
3882 	WARN_ON(ap->nr_active_links);
3883 	ap->nr_active_links = 0;
3884 }
3885 
3886 /**
3887  *	ata_do_eh - do standard error handling
3888  *	@ap: host port to handle error for
3889  *
3890  *	@prereset: prereset method (can be NULL)
3891  *	@softreset: softreset method (can be NULL)
3892  *	@hardreset: hardreset method (can be NULL)
3893  *	@postreset: postreset method (can be NULL)
3894  *
3895  *	Perform standard error handling sequence.
3896  *
3897  *	LOCKING:
3898  *	Kernel thread context (may sleep).
3899  */
3900 void ata_do_eh(struct ata_port *ap, ata_prereset_fn_t prereset,
3901 	       ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
3902 	       ata_postreset_fn_t postreset)
3903 {
3904 	struct ata_device *dev;
3905 	int rc;
3906 
3907 	ata_eh_autopsy(ap);
3908 	ata_eh_report(ap);
3909 
3910 	rc = ata_eh_recover(ap, prereset, softreset, hardreset, postreset,
3911 			    NULL);
3912 	if (rc) {
3913 		ata_for_each_dev(dev, &ap->link, ALL)
3914 			ata_dev_disable(dev);
3915 	}
3916 
3917 	ata_eh_finish(ap);
3918 }
3919 
3920 /**
3921  *	ata_std_error_handler - standard error handler
3922  *	@ap: host port to handle error for
3923  *
3924  *	Standard error handler
3925  *
3926  *	LOCKING:
3927  *	Kernel thread context (may sleep).
3928  */
3929 void ata_std_error_handler(struct ata_port *ap)
3930 {
3931 	struct ata_port_operations *ops = ap->ops;
3932 	ata_reset_fn_t hardreset = ops->hardreset;
3933 
3934 	/* ignore built-in hardreset if SCR access is not available */
3935 	if (hardreset == sata_std_hardreset && !sata_scr_valid(&ap->link))
3936 		hardreset = NULL;
3937 
3938 	ata_do_eh(ap, ops->prereset, ops->softreset, hardreset, ops->postreset);
3939 }
3940 
3941 #ifdef CONFIG_PM
3942 /**
3943  *	ata_eh_handle_port_suspend - perform port suspend operation
3944  *	@ap: port to suspend
3945  *
3946  *	Suspend @ap.
3947  *
3948  *	LOCKING:
3949  *	Kernel thread context (may sleep).
3950  */
3951 static void ata_eh_handle_port_suspend(struct ata_port *ap)
3952 {
3953 	unsigned long flags;
3954 	int rc = 0;
3955 
3956 	/* are we suspending? */
3957 	spin_lock_irqsave(ap->lock, flags);
3958 	if (!(ap->pflags & ATA_PFLAG_PM_PENDING) ||
3959 	    ap->pm_mesg.event == PM_EVENT_ON) {
3960 		spin_unlock_irqrestore(ap->lock, flags);
3961 		return;
3962 	}
3963 	spin_unlock_irqrestore(ap->lock, flags);
3964 
3965 	WARN_ON(ap->pflags & ATA_PFLAG_SUSPENDED);
3966 
3967 	/* tell ACPI we're suspending */
3968 	rc = ata_acpi_on_suspend(ap);
3969 	if (rc)
3970 		goto out;
3971 
3972 	/* suspend */
3973 	ata_eh_freeze_port(ap);
3974 
3975 	if (ap->ops->port_suspend)
3976 		rc = ap->ops->port_suspend(ap, ap->pm_mesg);
3977 
3978 	ata_acpi_set_state(ap, PMSG_SUSPEND);
3979  out:
3980 	/* report result */
3981 	spin_lock_irqsave(ap->lock, flags);
3982 
3983 	ap->pflags &= ~ATA_PFLAG_PM_PENDING;
3984 	if (rc == 0)
3985 		ap->pflags |= ATA_PFLAG_SUSPENDED;
3986 	else if (ap->pflags & ATA_PFLAG_FROZEN)
3987 		ata_port_schedule_eh(ap);
3988 
3989 	if (ap->pm_result) {
3990 		*ap->pm_result = rc;
3991 		ap->pm_result = NULL;
3992 	}
3993 
3994 	spin_unlock_irqrestore(ap->lock, flags);
3995 
3996 	return;
3997 }
3998 
3999 /**
4000  *	ata_eh_handle_port_resume - perform port resume operation
4001  *	@ap: port to resume
4002  *
4003  *	Resume @ap.
4004  *
4005  *	LOCKING:
4006  *	Kernel thread context (may sleep).
4007  */
4008 static void ata_eh_handle_port_resume(struct ata_port *ap)
4009 {
4010 	struct ata_link *link;
4011 	struct ata_device *dev;
4012 	unsigned long flags;
4013 	int rc = 0;
4014 
4015 	/* are we resuming? */
4016 	spin_lock_irqsave(ap->lock, flags);
4017 	if (!(ap->pflags & ATA_PFLAG_PM_PENDING) ||
4018 	    ap->pm_mesg.event != PM_EVENT_ON) {
4019 		spin_unlock_irqrestore(ap->lock, flags);
4020 		return;
4021 	}
4022 	spin_unlock_irqrestore(ap->lock, flags);
4023 
4024 	WARN_ON(!(ap->pflags & ATA_PFLAG_SUSPENDED));
4025 
4026 	/*
4027 	 * Error timestamps are in jiffies which doesn't run while
4028 	 * suspended and PHY events during resume isn't too uncommon.
4029 	 * When the two are combined, it can lead to unnecessary speed
4030 	 * downs if the machine is suspended and resumed repeatedly.
4031 	 * Clear error history.
4032 	 */
4033 	ata_for_each_link(link, ap, HOST_FIRST)
4034 		ata_for_each_dev(dev, link, ALL)
4035 			ata_ering_clear(&dev->ering);
4036 
4037 	ata_acpi_set_state(ap, PMSG_ON);
4038 
4039 	if (ap->ops->port_resume)
4040 		rc = ap->ops->port_resume(ap);
4041 
4042 	/* tell ACPI that we're resuming */
4043 	ata_acpi_on_resume(ap);
4044 
4045 	/* report result */
4046 	spin_lock_irqsave(ap->lock, flags);
4047 	ap->pflags &= ~(ATA_PFLAG_PM_PENDING | ATA_PFLAG_SUSPENDED);
4048 	if (ap->pm_result) {
4049 		*ap->pm_result = rc;
4050 		ap->pm_result = NULL;
4051 	}
4052 	spin_unlock_irqrestore(ap->lock, flags);
4053 }
4054 #endif /* CONFIG_PM */
4055