xref: /linux/drivers/ata/libata-pmp.c (revision 759e8756da00aa115d504a18155b1d1ee1cc12e8)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * libata-pmp.c - libata port multiplier support
4  *
5  * Copyright (c) 2007  SUSE Linux Products GmbH
6  * Copyright (c) 2007  Tejun Heo <teheo@suse.de>
7  */
8 
9 #include <linux/kernel.h>
10 #include <linux/export.h>
11 #include <linux/libata.h>
12 #include <linux/slab.h>
13 #include "libata.h"
14 #include "libata-transport.h"
15 
16 const struct ata_port_operations sata_pmp_port_ops = {
17 	.inherits		= &sata_port_ops,
18 	.pmp_reset.prereset	= ata_std_prereset,
19 	.pmp_reset.hardreset	= sata_std_hardreset,
20 	.pmp_reset.postreset	= ata_std_postreset,
21 	.error_handler		= sata_pmp_error_handler,
22 };
23 
24 /**
25  *	sata_pmp_read - read PMP register
26  *	@link: link to read PMP register for
27  *	@reg: register to read
28  *	@r_val: resulting value
29  *
30  *	Read PMP register.
31  *
32  *	LOCKING:
33  *	Kernel thread context (may sleep).
34  *
35  *	RETURNS:
36  *	0 on success, AC_ERR_* mask on failure.
37  */
38 static unsigned int sata_pmp_read(struct ata_link *link, int reg, u32 *r_val)
39 {
40 	struct ata_port *ap = link->ap;
41 	struct ata_device *pmp_dev = ap->link.device;
42 	struct ata_taskfile tf;
43 	unsigned int err_mask;
44 
45 	ata_tf_init(pmp_dev, &tf);
46 	tf.command = ATA_CMD_PMP_READ;
47 	tf.protocol = ATA_PROT_NODATA;
48 	tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE | ATA_TFLAG_LBA48;
49 	tf.feature = reg;
50 	tf.device = link->pmp;
51 
52 	err_mask = ata_exec_internal(pmp_dev, &tf, NULL, DMA_NONE, NULL, 0,
53 				     SATA_PMP_RW_TIMEOUT);
54 	if (err_mask)
55 		return err_mask;
56 
57 	*r_val = tf.nsect | tf.lbal << 8 | tf.lbam << 16 | tf.lbah << 24;
58 	return 0;
59 }
60 
61 /**
62  *	sata_pmp_write - write PMP register
63  *	@link: link to write PMP register for
64  *	@reg: register to write
65  *	@val: value to write
66  *
67  *	Write PMP register.
68  *
69  *	LOCKING:
70  *	Kernel thread context (may sleep).
71  *
72  *	RETURNS:
73  *	0 on success, AC_ERR_* mask on failure.
74  */
75 static unsigned int sata_pmp_write(struct ata_link *link, int reg, u32 val)
76 {
77 	struct ata_port *ap = link->ap;
78 	struct ata_device *pmp_dev = ap->link.device;
79 	struct ata_taskfile tf;
80 
81 	ata_tf_init(pmp_dev, &tf);
82 	tf.command = ATA_CMD_PMP_WRITE;
83 	tf.protocol = ATA_PROT_NODATA;
84 	tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE | ATA_TFLAG_LBA48;
85 	tf.feature = reg;
86 	tf.device = link->pmp;
87 	tf.nsect = val & 0xff;
88 	tf.lbal = (val >> 8) & 0xff;
89 	tf.lbam = (val >> 16) & 0xff;
90 	tf.lbah = (val >> 24) & 0xff;
91 
92 	return ata_exec_internal(pmp_dev, &tf, NULL, DMA_NONE, NULL, 0,
93 				 SATA_PMP_RW_TIMEOUT);
94 }
95 
96 /**
97  *	sata_pmp_qc_defer_cmd_switch - qc_defer for command switching PMP
98  *	@qc: ATA command in question
99  *
100  *	A host which has command switching PMP support cannot issue
101  *	commands to multiple links simultaneously.
102  *
103  *	LOCKING:
104  *	spin_lock_irqsave(host lock)
105  *
106  *	RETURNS:
107  *	ATA_DEFER_* if deferring is needed, 0 otherwise.
108  */
109 int sata_pmp_qc_defer_cmd_switch(struct ata_queued_cmd *qc)
110 {
111 	struct ata_link *link = qc->dev->link;
112 	struct ata_port *ap = link->ap;
113 	int ret;
114 
115 	if (ap->excl_link == NULL || ap->excl_link == link) {
116 		if (ap->nr_active_links == 0 || ata_link_active(link)) {
117 			qc->flags |= ATA_QCFLAG_CLEAR_EXCL;
118 			ret = ata_std_qc_defer(qc);
119 			if (ret == ATA_DEFER_LINK)
120 				return ATA_DEFER_LINK_EXCL;
121 			return ret;
122 		}
123 
124 		/*
125 		 * Note: ap->excl_link contains the link that is next in line,
126 		 * i.e. implicit round robin. If there is only one link
127 		 * dispatching, ap->excl_link will be left unclaimed, allowing
128 		 * other links to set ap->excl_link, ensuring that the currently
129 		 * active link cannot queue any more.
130 		 */
131 		ap->excl_link = link;
132 	}
133 
134 	return ATA_DEFER_PORT;
135 }
136 
137 /**
138  *	sata_pmp_scr_read - read PSCR
139  *	@link: ATA link to read PSCR for
140  *	@reg: PSCR to read
141  *	@r_val: resulting value
142  *
143  *	Read PSCR @reg into @r_val for @link, to be called from
144  *	ata_scr_read().
145  *
146  *	LOCKING:
147  *	Kernel thread context (may sleep).
148  *
149  *	RETURNS:
150  *	0 on success, -errno on failure.
151  */
152 int sata_pmp_scr_read(struct ata_link *link, int reg, u32 *r_val)
153 {
154 	unsigned int err_mask;
155 
156 	if (reg > SATA_PMP_PSCR_CONTROL)
157 		return -EINVAL;
158 
159 	err_mask = sata_pmp_read(link, reg, r_val);
160 	if (err_mask) {
161 		ata_link_warn(link, "failed to read SCR %d (Emask=0x%x)\n",
162 			      reg, err_mask);
163 		return -EIO;
164 	}
165 	return 0;
166 }
167 
168 /**
169  *	sata_pmp_scr_write - write PSCR
170  *	@link: ATA link to write PSCR for
171  *	@reg: PSCR to write
172  *	@val: value to be written
173  *
174  *	Write @val to PSCR @reg for @link, to be called from
175  *	ata_scr_write() and ata_scr_write_flush().
176  *
177  *	LOCKING:
178  *	Kernel thread context (may sleep).
179  *
180  *	RETURNS:
181  *	0 on success, -errno on failure.
182  */
183 int sata_pmp_scr_write(struct ata_link *link, int reg, u32 val)
184 {
185 	unsigned int err_mask;
186 
187 	if (reg > SATA_PMP_PSCR_CONTROL)
188 		return -EINVAL;
189 
190 	err_mask = sata_pmp_write(link, reg, val);
191 	if (err_mask) {
192 		ata_link_warn(link, "failed to write SCR %d (Emask=0x%x)\n",
193 			      reg, err_mask);
194 		return -EIO;
195 	}
196 	return 0;
197 }
198 
199 /**
200  *	sata_pmp_set_lpm - configure LPM for a PMP link
201  *	@link: PMP link to configure LPM for
202  *	@policy: target LPM policy
203  *	@hints: LPM hints
204  *
205  *	Configure LPM for @link.  This function will contain any PMP
206  *	specific workarounds if necessary.
207  *
208  *	LOCKING:
209  *	EH context.
210  *
211  *	RETURNS:
212  *	0 on success, -errno on failure.
213  */
214 int sata_pmp_set_lpm(struct ata_link *link, enum ata_lpm_policy policy,
215 		     unsigned hints)
216 {
217 	return sata_link_scr_lpm(link, policy, true);
218 }
219 
220 /**
221  *	sata_pmp_read_gscr - read GSCR block of SATA PMP
222  *	@dev: PMP device
223  *	@gscr: buffer to read GSCR block into
224  *
225  *	Read selected PMP GSCRs from the PMP at @dev.  This will serve
226  *	as configuration and identification info for the PMP.
227  *
228  *	LOCKING:
229  *	Kernel thread context (may sleep).
230  *
231  *	RETURNS:
232  *	0 on success, -errno on failure.
233  */
234 static int sata_pmp_read_gscr(struct ata_device *dev, u32 *gscr)
235 {
236 	static const int gscr_to_read[] = { 0, 1, 2, 32, 33, 64, 96 };
237 	int i;
238 
239 	for (i = 0; i < ARRAY_SIZE(gscr_to_read); i++) {
240 		int reg = gscr_to_read[i];
241 		unsigned int err_mask;
242 
243 		err_mask = sata_pmp_read(dev->link, reg, &gscr[reg]);
244 		if (err_mask) {
245 			ata_dev_err(dev, "failed to read PMP GSCR[%d] (Emask=0x%x)\n",
246 				    reg, err_mask);
247 			return -EIO;
248 		}
249 	}
250 
251 	return 0;
252 }
253 
254 static const char *sata_pmp_spec_rev_str(const u32 *gscr)
255 {
256 	u32 rev = gscr[SATA_PMP_GSCR_REV];
257 
258 	if (rev & (1 << 3))
259 		return "1.2";
260 	if (rev & (1 << 2))
261 		return "1.1";
262 	if (rev & (1 << 1))
263 		return "1.0";
264 	return "<unknown>";
265 }
266 
267 #define PMP_GSCR_SII_POL 129
268 
269 static int sata_pmp_configure(struct ata_device *dev, int print_info)
270 {
271 	struct ata_port *ap = dev->link->ap;
272 	u32 *gscr = dev->gscr;
273 	u16 vendor = sata_pmp_gscr_vendor(gscr);
274 	u16 devid = sata_pmp_gscr_devid(gscr);
275 	unsigned int err_mask = 0;
276 	const char *reason;
277 	int nr_ports, rc;
278 
279 	nr_ports = sata_pmp_gscr_ports(gscr);
280 
281 	if (nr_ports <= 0 || nr_ports > SATA_PMP_MAX_PORTS) {
282 		rc = -EINVAL;
283 		reason = "invalid nr_ports";
284 		goto fail;
285 	}
286 
287 	if ((ap->flags & ATA_FLAG_AN) &&
288 	    (gscr[SATA_PMP_GSCR_FEAT] & SATA_PMP_FEAT_NOTIFY))
289 		dev->flags |= ATA_DFLAG_AN;
290 
291 	/* monitor SERR_PHYRDY_CHG on fan-out ports */
292 	err_mask = sata_pmp_write(dev->link, SATA_PMP_GSCR_ERROR_EN,
293 				  SERR_PHYRDY_CHG);
294 	if (err_mask) {
295 		rc = -EIO;
296 		reason = "failed to write GSCR_ERROR_EN";
297 		goto fail;
298 	}
299 
300 	/* Disable sending Early R_OK.
301 	 * With "cached read" HDD testing and multiple ports busy on a SATA
302 	 * host controller, 3x26 PMP will very rarely drop a deferred
303 	 * R_OK that was intended for the host. Symptom will be all
304 	 * 5 drives under test will timeout, get reset, and recover.
305 	 */
306 	if (vendor == 0x1095 && (devid == 0x3726 || devid == 0x3826)) {
307 		u32 reg;
308 
309 		err_mask = sata_pmp_read(&ap->link, PMP_GSCR_SII_POL, &reg);
310 		if (err_mask) {
311 			rc = -EIO;
312 			reason = "failed to read Sil3x26 Private Register";
313 			goto fail;
314 		}
315 		reg &= ~0x1;
316 		err_mask = sata_pmp_write(&ap->link, PMP_GSCR_SII_POL, reg);
317 		if (err_mask) {
318 			rc = -EIO;
319 			reason = "failed to write Sil3x26 Private Register";
320 			goto fail;
321 		}
322 	}
323 
324 	if (print_info) {
325 		ata_dev_info(dev, "Port Multiplier %s, "
326 			     "0x%04x:0x%04x r%d, %d ports, feat 0x%x/0x%x\n",
327 			     sata_pmp_spec_rev_str(gscr), vendor, devid,
328 			     sata_pmp_gscr_rev(gscr),
329 			     nr_ports, gscr[SATA_PMP_GSCR_FEAT_EN],
330 			     gscr[SATA_PMP_GSCR_FEAT]);
331 
332 		if (!(dev->flags & ATA_DFLAG_AN))
333 			ata_dev_info(dev,
334 				"Asynchronous notification not supported, "
335 				"hotplug won't work on fan-out ports. Use warm-plug instead.\n");
336 	}
337 
338 	return 0;
339 
340  fail:
341 	ata_dev_err(dev,
342 		    "failed to configure Port Multiplier (%s, Emask=0x%x)\n",
343 		    reason, err_mask);
344 	return rc;
345 }
346 
347 static int sata_pmp_init_links (struct ata_port *ap, int nr_ports)
348 {
349 	struct ata_link *pmp_link = ap->pmp_link;
350 	int i, err;
351 
352 	if (!pmp_link) {
353 		pmp_link = kzalloc_objs(pmp_link[0], SATA_PMP_MAX_PORTS,
354 					GFP_NOIO);
355 		if (!pmp_link)
356 			return -ENOMEM;
357 
358 		for (i = 0; i < SATA_PMP_MAX_PORTS; i++)
359 			ata_link_init(ap, &pmp_link[i], i);
360 
361 		ap->pmp_link = pmp_link;
362 
363 		for (i = 0; i < SATA_PMP_MAX_PORTS; i++) {
364 			err = ata_tlink_add(&pmp_link[i]);
365 			if (err) {
366 				goto err_tlink;
367 			}
368 		}
369 	}
370 
371 	for (i = 0; i < nr_ports; i++) {
372 		struct ata_link *link = &pmp_link[i];
373 		struct ata_eh_context *ehc = &link->eh_context;
374 
375 		link->flags = 0;
376 		ehc->i.probe_mask |= ATA_ALL_DEVICES;
377 		ehc->i.action |= ATA_EH_RESET;
378 	}
379 
380 	return 0;
381   err_tlink:
382 	while (--i >= 0)
383 		ata_tlink_delete(&pmp_link[i]);
384 	kfree(pmp_link);
385 	ap->pmp_link = NULL;
386 	return err;
387 }
388 
389 static void sata_pmp_quirks(struct ata_port *ap)
390 {
391 	u32 *gscr = ap->link.device->gscr;
392 	u16 vendor = sata_pmp_gscr_vendor(gscr);
393 	u16 devid = sata_pmp_gscr_devid(gscr);
394 	struct ata_link *link;
395 
396 	if (vendor == 0x1095 && (devid == 0x3726 || devid == 0x3826)) {
397 		/* sil3x26 quirks */
398 		ata_for_each_link(link, ap, EDGE) {
399 			/* link reports offline after LPM */
400 			link->flags |= ATA_LFLAG_NO_LPM;
401 
402 			/*
403 			 * Class code report is unreliable and SRST times
404 			 * out under certain configurations.
405 			 */
406 			if (link->pmp < 5)
407 				link->flags |= ATA_LFLAG_NO_SRST |
408 					       ATA_LFLAG_ASSUME_ATA;
409 
410 			/* port 5 is for SEMB device and it doesn't like SRST */
411 			if (link->pmp == 5)
412 				link->flags |= ATA_LFLAG_NO_SRST |
413 					       ATA_LFLAG_ASSUME_SEMB;
414 		}
415 	} else if (vendor == 0x1095 && devid == 0x4723) {
416 		/*
417 		 * sil4723 quirks
418 		 *
419 		 * Link reports offline after LPM.  Class code report is
420 		 * unreliable.  SIMG PMPs never got SRST reliable and the
421 		 * config device at port 2 locks up on SRST.
422 		 */
423 		ata_for_each_link(link, ap, EDGE)
424 			link->flags |= ATA_LFLAG_NO_LPM |
425 				       ATA_LFLAG_NO_SRST |
426 				       ATA_LFLAG_ASSUME_ATA;
427 	} else if (vendor == 0x1095 && devid == 0x4726) {
428 		/* sil4726 quirks */
429 		ata_for_each_link(link, ap, EDGE) {
430 			/* link reports offline after LPM */
431 			link->flags |= ATA_LFLAG_NO_LPM;
432 
433 			/* Class code report is unreliable and SRST
434 			 * times out under certain configurations.
435 			 * Config device can be at port 0 or 5 and
436 			 * locks up on SRST.
437 			 */
438 			if (link->pmp <= 5)
439 				link->flags |= ATA_LFLAG_NO_SRST |
440 					       ATA_LFLAG_ASSUME_ATA;
441 
442 			/* Port 6 is for SEMB device which doesn't
443 			 * like SRST either.
444 			 */
445 			if (link->pmp == 6)
446 				link->flags |= ATA_LFLAG_NO_SRST |
447 					       ATA_LFLAG_ASSUME_SEMB;
448 		}
449 	} else if (vendor == 0x1095 && (devid == 0x5723 || devid == 0x5733 ||
450 					devid == 0x5734 || devid == 0x5744)) {
451 		/* sil5723/5744 quirks */
452 
453 		/* sil5723/5744 has either two or three downstream
454 		 * ports depending on operation mode.  The last port
455 		 * is empty if any actual IO device is available or
456 		 * occupied by a pseudo configuration device
457 		 * otherwise.  Don't try hard to recover it.
458 		 */
459 		ap->pmp_link[ap->nr_pmp_links - 1].flags |= ATA_LFLAG_NO_RETRY;
460 	} else if (vendor == 0x197b && (devid == 0x2352 || devid == 0x0325)) {
461 		/*
462 		 * 0x2352: found in Thermaltake BlackX Duet, jmicron JMB350?
463 		 * 0x0325: jmicron JMB394.
464 		 */
465 		ata_for_each_link(link, ap, EDGE) {
466 			/* SRST breaks detection and disks get misclassified
467 			 * LPM disabled to avoid potential problems
468 			 */
469 			link->flags |= ATA_LFLAG_NO_LPM |
470 				       ATA_LFLAG_NO_SRST |
471 				       ATA_LFLAG_ASSUME_ATA;
472 		}
473 	} else if (vendor == 0x11ab && devid == 0x4140) {
474 		/* Marvell 4140 quirks */
475 		ata_for_each_link(link, ap, EDGE) {
476 			/* port 4 is for SEMB device and it doesn't like SRST */
477 			if (link->pmp == 4)
478 				link->flags |= ATA_LFLAG_DISABLED;
479 		}
480 	}
481 }
482 
483 /**
484  *	sata_pmp_attach - attach a SATA PMP device
485  *	@dev: SATA PMP device to attach
486  *
487  *	Configure and attach SATA PMP device @dev.  This function is
488  *	also responsible for allocating and initializing PMP links.
489  *
490  *	LOCKING:
491  *	Kernel thread context (may sleep).
492  *
493  *	RETURNS:
494  *	0 on success, -errno on failure.
495  */
496 int sata_pmp_attach(struct ata_device *dev)
497 {
498 	struct ata_link *link = dev->link;
499 	struct ata_port *ap = link->ap;
500 	unsigned long flags;
501 	struct ata_link *tlink;
502 	int rc;
503 
504 	/* is it hanging off the right place? */
505 	if (!sata_pmp_supported(ap)) {
506 		ata_dev_err(dev, "host does not support Port Multiplier\n");
507 		return -EINVAL;
508 	}
509 
510 	if (!ata_is_host_link(link)) {
511 		ata_dev_err(dev, "Port Multipliers cannot be nested\n");
512 		return -EINVAL;
513 	}
514 
515 	if (dev->devno) {
516 		ata_dev_err(dev, "Port Multiplier must be the first device\n");
517 		return -EINVAL;
518 	}
519 
520 	WARN_ON(link->pmp != 0);
521 	link->pmp = SATA_PMP_CTRL_PORT;
522 
523 	/* read GSCR block */
524 	rc = sata_pmp_read_gscr(dev, dev->gscr);
525 	if (rc)
526 		goto fail;
527 
528 	/* config PMP */
529 	rc = sata_pmp_configure(dev, 1);
530 	if (rc)
531 		goto fail;
532 
533 	rc = sata_pmp_init_links(ap, sata_pmp_gscr_ports(dev->gscr));
534 	if (rc) {
535 		ata_dev_info(dev, "failed to initialize PMP links\n");
536 		goto fail;
537 	}
538 
539 	/* attach it */
540 	spin_lock_irqsave(ap->lock, flags);
541 	WARN_ON(ap->nr_pmp_links);
542 	ap->nr_pmp_links = sata_pmp_gscr_ports(dev->gscr);
543 	spin_unlock_irqrestore(ap->lock, flags);
544 
545 	sata_pmp_quirks(ap);
546 
547 	if (ap->ops->pmp_attach)
548 		ap->ops->pmp_attach(ap);
549 
550 	ata_for_each_link(tlink, ap, EDGE)
551 		sata_link_init_spd(tlink);
552 
553 	return 0;
554 
555  fail:
556 	link->pmp = 0;
557 	return rc;
558 }
559 
560 /**
561  *	sata_pmp_detach - detach a SATA PMP device
562  *	@dev: SATA PMP device to detach
563  *
564  *	Detach SATA PMP device @dev.  This function is also
565  *	responsible for deconfiguring PMP links.
566  *
567  *	LOCKING:
568  *	Kernel thread context (may sleep).
569  */
570 static void sata_pmp_detach(struct ata_device *dev)
571 {
572 	struct ata_link *link = dev->link;
573 	struct ata_port *ap = link->ap;
574 	struct ata_link *tlink;
575 	unsigned long flags;
576 
577 	ata_dev_info(dev, "Port Multiplier detaching\n");
578 
579 	WARN_ON(!ata_is_host_link(link) || dev->devno ||
580 		link->pmp != SATA_PMP_CTRL_PORT);
581 
582 	if (ap->ops->pmp_detach)
583 		ap->ops->pmp_detach(ap);
584 
585 	ata_for_each_link(tlink, ap, EDGE) {
586 		WARN_ON(tlink->deferred_qc);
587 		cancel_work_sync(&tlink->deferred_qc_work);
588 		ata_eh_detach_dev(tlink->device);
589 	}
590 
591 	spin_lock_irqsave(ap->lock, flags);
592 	ap->nr_pmp_links = 0;
593 	link->pmp = 0;
594 	spin_unlock_irqrestore(ap->lock, flags);
595 }
596 
597 /**
598  *	sata_pmp_same_pmp - does new GSCR matches the configured PMP?
599  *	@dev: PMP device to compare against
600  *	@new_gscr: GSCR block of the new device
601  *
602  *	Compare @new_gscr against @dev and determine whether @dev is
603  *	the PMP described by @new_gscr.
604  *
605  *	LOCKING:
606  *	None.
607  *
608  *	RETURNS:
609  *	1 if @dev matches @new_gscr, 0 otherwise.
610  */
611 static int sata_pmp_same_pmp(struct ata_device *dev, const u32 *new_gscr)
612 {
613 	const u32 *old_gscr = dev->gscr;
614 	u16 old_vendor, new_vendor, old_devid, new_devid;
615 	int old_nr_ports, new_nr_ports;
616 
617 	old_vendor = sata_pmp_gscr_vendor(old_gscr);
618 	new_vendor = sata_pmp_gscr_vendor(new_gscr);
619 	old_devid = sata_pmp_gscr_devid(old_gscr);
620 	new_devid = sata_pmp_gscr_devid(new_gscr);
621 	old_nr_ports = sata_pmp_gscr_ports(old_gscr);
622 	new_nr_ports = sata_pmp_gscr_ports(new_gscr);
623 
624 	if (old_vendor != new_vendor) {
625 		ata_dev_info(dev,
626 			     "Port Multiplier vendor mismatch '0x%x' != '0x%x'\n",
627 			     old_vendor, new_vendor);
628 		return 0;
629 	}
630 
631 	if (old_devid != new_devid) {
632 		ata_dev_info(dev,
633 			     "Port Multiplier device ID mismatch '0x%x' != '0x%x'\n",
634 			     old_devid, new_devid);
635 		return 0;
636 	}
637 
638 	if (old_nr_ports != new_nr_ports) {
639 		ata_dev_info(dev,
640 			     "Port Multiplier nr_ports mismatch '0x%x' != '0x%x'\n",
641 			     old_nr_ports, new_nr_ports);
642 		return 0;
643 	}
644 
645 	return 1;
646 }
647 
648 /**
649  *	sata_pmp_revalidate - revalidate SATA PMP
650  *	@dev: PMP device to revalidate
651  *	@new_class: new class code
652  *
653  *	Re-read GSCR block and make sure @dev is still attached to the
654  *	port and properly configured.
655  *
656  *	LOCKING:
657  *	Kernel thread context (may sleep).
658  *
659  *	RETURNS:
660  *	0 on success, -errno otherwise.
661  */
662 static int sata_pmp_revalidate(struct ata_device *dev, unsigned int new_class)
663 {
664 	struct ata_link *link = dev->link;
665 	u32 *gscr = (void *)dev->sector_buf;
666 	int rc;
667 
668 	ata_eh_about_to_do(link, NULL, ATA_EH_REVALIDATE);
669 
670 	if (!ata_dev_enabled(dev)) {
671 		rc = -ENODEV;
672 		goto fail;
673 	}
674 
675 	/* wrong class? */
676 	if (ata_class_enabled(new_class) && new_class != ATA_DEV_PMP) {
677 		rc = -ENODEV;
678 		goto fail;
679 	}
680 
681 	/* read GSCR */
682 	rc = sata_pmp_read_gscr(dev, gscr);
683 	if (rc)
684 		goto fail;
685 
686 	/* is the pmp still there? */
687 	if (!sata_pmp_same_pmp(dev, gscr)) {
688 		rc = -ENODEV;
689 		goto fail;
690 	}
691 
692 	memcpy(dev->gscr, gscr, sizeof(gscr[0]) * SATA_PMP_GSCR_DWORDS);
693 
694 	rc = sata_pmp_configure(dev, 0);
695 	if (rc)
696 		goto fail;
697 
698 	ata_eh_done(link, NULL, ATA_EH_REVALIDATE);
699 
700 	return 0;
701 
702  fail:
703 	ata_dev_err(dev, "PMP revalidation failed (errno=%d)\n", rc);
704 	return rc;
705 }
706 
707 /**
708  *	sata_pmp_revalidate_quick - revalidate SATA PMP quickly
709  *	@dev: PMP device to revalidate
710  *
711  *	Make sure the attached PMP is accessible.
712  *
713  *	LOCKING:
714  *	Kernel thread context (may sleep).
715  *
716  *	RETURNS:
717  *	0 on success, -errno otherwise.
718  */
719 static int sata_pmp_revalidate_quick(struct ata_device *dev)
720 {
721 	unsigned int err_mask;
722 	u32 prod_id;
723 
724 	err_mask = sata_pmp_read(dev->link, SATA_PMP_GSCR_PROD_ID, &prod_id);
725 	if (err_mask) {
726 		ata_dev_err(dev,
727 			    "failed to read PMP product ID (Emask=0x%x)\n",
728 			    err_mask);
729 		return -EIO;
730 	}
731 
732 	if (prod_id != dev->gscr[SATA_PMP_GSCR_PROD_ID]) {
733 		ata_dev_err(dev, "PMP product ID mismatch\n");
734 		/* something weird is going on, request full PMP recovery */
735 		return -EIO;
736 	}
737 
738 	return 0;
739 }
740 
741 /**
742  *	sata_pmp_eh_recover_pmp - recover PMP
743  *	@ap: ATA port PMP is attached to
744  *	@reset_ops: The set of reset operations to use
745  *
746  *	Recover PMP attached to @ap.  Recovery procedure is somewhat
747  *	similar to that of ata_eh_recover() except that reset should
748  *	always be performed in hard->soft sequence and recovery
749  *	failure results in PMP detachment.
750  *
751  *	LOCKING:
752  *	Kernel thread context (may sleep).
753  *
754  *	RETURNS:
755  *	0 on success, -errno on failure.
756  */
757 static int sata_pmp_eh_recover_pmp(struct ata_port *ap,
758 				   struct ata_reset_operations *reset_ops)
759 {
760 	struct ata_link *link = &ap->link;
761 	struct ata_eh_context *ehc = &link->eh_context;
762 	struct ata_device *dev = link->device;
763 	int tries = ATA_EH_PMP_TRIES;
764 	int detach = 0, rc = 0;
765 	int reval_failed = 0;
766 
767 	if (dev->flags & ATA_DFLAG_DETACH) {
768 		detach = 1;
769 		rc = -ENODEV;
770 		goto fail;
771 	}
772 
773  retry:
774 	ehc->classes[0] = ATA_DEV_UNKNOWN;
775 
776 	if (ehc->i.action & ATA_EH_RESET) {
777 		struct ata_link *tlink;
778 
779 		/* reset */
780 		rc = ata_eh_reset(link, 0, reset_ops);
781 		if (rc) {
782 			ata_link_err(link, "failed to reset PMP, giving up\n");
783 			goto fail;
784 		}
785 
786 		/* PMP is reset, SErrors cannot be trusted, scan all */
787 		ata_for_each_link(tlink, ap, EDGE) {
788 			struct ata_eh_context *ehc = &tlink->eh_context;
789 
790 			ehc->i.probe_mask |= ATA_ALL_DEVICES;
791 			ehc->i.action |= ATA_EH_RESET;
792 		}
793 	}
794 
795 	/* If revalidation is requested, revalidate and reconfigure;
796 	 * otherwise, do quick revalidation.
797 	 */
798 	if (ehc->i.action & ATA_EH_REVALIDATE)
799 		rc = sata_pmp_revalidate(dev, ehc->classes[0]);
800 	else
801 		rc = sata_pmp_revalidate_quick(dev);
802 
803 	if (rc) {
804 		tries--;
805 
806 		if (rc == -ENODEV) {
807 			ehc->i.probe_mask |= ATA_ALL_DEVICES;
808 			detach = 1;
809 			/* give it just two more chances */
810 			tries = min(tries, 2);
811 		}
812 
813 		if (tries) {
814 			/* consecutive revalidation failures? speed down */
815 			if (reval_failed)
816 				sata_down_spd_limit(link, 0);
817 			else
818 				reval_failed = 1;
819 
820 			ehc->i.action |= ATA_EH_RESET;
821 			goto retry;
822 		} else {
823 			ata_dev_err(dev,
824 				    "failed to recover PMP after %d tries, giving up\n",
825 				    ATA_EH_PMP_TRIES);
826 			goto fail;
827 		}
828 	}
829 
830 	/* okay, PMP resurrected */
831 	ehc->i.flags = 0;
832 
833 	return 0;
834 
835  fail:
836 	sata_pmp_detach(dev);
837 	if (detach)
838 		ata_eh_detach_dev(dev);
839 	else
840 		ata_dev_disable(dev);
841 
842 	return rc;
843 }
844 
845 static int sata_pmp_eh_handle_disabled_links(struct ata_port *ap)
846 {
847 	struct ata_link *link;
848 	unsigned long flags;
849 	int rc;
850 
851 	spin_lock_irqsave(ap->lock, flags);
852 
853 	ata_for_each_link(link, ap, EDGE) {
854 		if (!(link->flags & ATA_LFLAG_DISABLED))
855 			continue;
856 
857 		spin_unlock_irqrestore(ap->lock, flags);
858 
859 		/* Some PMPs require hardreset sequence to get
860 		 * SError.N working.
861 		 */
862 		sata_link_hardreset(link, sata_deb_timing_normal,
863 				ata_deadline(jiffies, ATA_TMOUT_INTERNAL_QUICK),
864 				NULL, NULL);
865 
866 		/* unconditionally clear SError.N */
867 		rc = sata_scr_write(link, SCR_ERROR, SERR_PHYRDY_CHG);
868 		if (rc) {
869 			ata_link_err(link,
870 				     "failed to clear SError.N (errno=%d)\n",
871 				     rc);
872 			return rc;
873 		}
874 
875 		spin_lock_irqsave(ap->lock, flags);
876 	}
877 
878 	spin_unlock_irqrestore(ap->lock, flags);
879 
880 	return 0;
881 }
882 
883 static int sata_pmp_handle_link_fail(struct ata_link *link, int *link_tries)
884 {
885 	struct ata_port *ap = link->ap;
886 	unsigned long flags;
887 
888 	if (link_tries[link->pmp] && --link_tries[link->pmp])
889 		return 1;
890 
891 	/* disable this link */
892 	if (!(link->flags & ATA_LFLAG_DISABLED)) {
893 		ata_link_warn(link,
894 			"failed to recover link after %d tries, disabling\n",
895 			ATA_EH_PMP_LINK_TRIES);
896 
897 		spin_lock_irqsave(ap->lock, flags);
898 		link->flags |= ATA_LFLAG_DISABLED;
899 		spin_unlock_irqrestore(ap->lock, flags);
900 	}
901 
902 	ata_dev_disable(link->device);
903 	link->eh_context.i.action = 0;
904 
905 	return 0;
906 }
907 
908 /**
909  *	sata_pmp_eh_recover - recover PMP-enabled port
910  *	@ap: ATA port to recover
911  *
912  *	Drive EH recovery operation for PMP enabled port @ap.  This
913  *	function recovers host and PMP ports with proper retrials and
914  *	fallbacks.  Actual recovery operations are performed using
915  *	ata_eh_recover() and sata_pmp_eh_recover_pmp().
916  *
917  *	LOCKING:
918  *	Kernel thread context (may sleep).
919  *
920  *	RETURNS:
921  *	0 on success, -errno on failure.
922  */
923 static int sata_pmp_eh_recover(struct ata_port *ap)
924 {
925 	struct ata_port_operations *ops = ap->ops;
926 	int pmp_tries, link_tries[SATA_PMP_MAX_PORTS];
927 	struct ata_link *pmp_link = &ap->link;
928 	struct ata_device *pmp_dev = pmp_link->device;
929 	struct ata_eh_context *pmp_ehc = &pmp_link->eh_context;
930 	u32 *gscr = pmp_dev->gscr;
931 	struct ata_link *link;
932 	struct ata_device *dev;
933 	unsigned int err_mask;
934 	u32 gscr_error, sntf;
935 	int cnt, rc;
936 
937 	pmp_tries = ATA_EH_PMP_TRIES;
938 	ata_for_each_link(link, ap, EDGE)
939 		link_tries[link->pmp] = ATA_EH_PMP_LINK_TRIES;
940 
941  retry:
942 	/* PMP attached? */
943 	if (!sata_pmp_attached(ap)) {
944 		rc = ata_eh_recover(ap, &ops->reset, NULL);
945 		if (rc) {
946 			ata_for_each_dev(dev, &ap->link, ALL)
947 				ata_dev_disable(dev);
948 			return rc;
949 		}
950 
951 		if (pmp_dev->class != ATA_DEV_PMP)
952 			return 0;
953 
954 		/* new PMP online */
955 		ata_for_each_link(link, ap, EDGE)
956 			link_tries[link->pmp] = ATA_EH_PMP_LINK_TRIES;
957 
958 		/* fall through */
959 	}
960 
961 	/* recover pmp */
962 	rc = sata_pmp_eh_recover_pmp(ap, &ops->reset);
963 	if (rc)
964 		goto pmp_fail;
965 
966 	/* PHY event notification can disturb reset and other recovery
967 	 * operations.  Turn it off.
968 	 */
969 	if (gscr[SATA_PMP_GSCR_FEAT_EN] & SATA_PMP_FEAT_NOTIFY) {
970 		gscr[SATA_PMP_GSCR_FEAT_EN] &= ~SATA_PMP_FEAT_NOTIFY;
971 
972 		err_mask = sata_pmp_write(pmp_link, SATA_PMP_GSCR_FEAT_EN,
973 					  gscr[SATA_PMP_GSCR_FEAT_EN]);
974 		if (err_mask) {
975 			ata_link_warn(pmp_link,
976 				"failed to disable NOTIFY (err_mask=0x%x)\n",
977 				err_mask);
978 			goto pmp_fail;
979 		}
980 	}
981 
982 	/* handle disabled links */
983 	rc = sata_pmp_eh_handle_disabled_links(ap);
984 	if (rc)
985 		goto pmp_fail;
986 
987 	/* recover links */
988 	rc = ata_eh_recover(ap, &ops->pmp_reset, &link);
989 	if (rc)
990 		goto link_fail;
991 
992 	/* clear SNotification */
993 	rc = sata_scr_read(&ap->link, SCR_NOTIFICATION, &sntf);
994 	if (rc == 0)
995 		sata_scr_write(&ap->link, SCR_NOTIFICATION, sntf);
996 
997 	/*
998 	 * If LPM is active on any fan-out port, hotplug wouldn't
999 	 * work.  Return w/ PHY event notification disabled.
1000 	 */
1001 	ata_for_each_link(link, ap, EDGE)
1002 		if (link->lpm_policy > ATA_LPM_MAX_POWER)
1003 			return 0;
1004 
1005 	/*
1006 	 * Connection status might have changed while resetting other
1007 	 * links, enable notification and check SATA_PMP_GSCR_ERROR
1008 	 * before returning.
1009 	 */
1010 
1011 	/* enable notification */
1012 	if (pmp_dev->flags & ATA_DFLAG_AN) {
1013 		gscr[SATA_PMP_GSCR_FEAT_EN] |= SATA_PMP_FEAT_NOTIFY;
1014 
1015 		err_mask = sata_pmp_write(pmp_link, SATA_PMP_GSCR_FEAT_EN,
1016 					  gscr[SATA_PMP_GSCR_FEAT_EN]);
1017 		if (err_mask) {
1018 			ata_dev_err(pmp_dev,
1019 				    "failed to write PMP_FEAT_EN (Emask=0x%x)\n",
1020 				    err_mask);
1021 			rc = -EIO;
1022 			goto pmp_fail;
1023 		}
1024 	}
1025 
1026 	/* check GSCR_ERROR */
1027 	err_mask = sata_pmp_read(pmp_link, SATA_PMP_GSCR_ERROR, &gscr_error);
1028 	if (err_mask) {
1029 		ata_dev_err(pmp_dev,
1030 			    "failed to read PMP_GSCR_ERROR (Emask=0x%x)\n",
1031 			    err_mask);
1032 		rc = -EIO;
1033 		goto pmp_fail;
1034 	}
1035 
1036 	cnt = 0;
1037 	ata_for_each_link(link, ap, EDGE) {
1038 		if (!(gscr_error & (1 << link->pmp)))
1039 			continue;
1040 
1041 		if (sata_pmp_handle_link_fail(link, link_tries)) {
1042 			ata_ehi_hotplugged(&link->eh_context.i);
1043 			cnt++;
1044 		} else {
1045 			ata_link_warn(link,
1046 				"PHY status changed but maxed out on retries, giving up\n");
1047 			ata_link_warn(link,
1048 				"Manually issue scan to resume this link\n");
1049 		}
1050 	}
1051 
1052 	if (cnt) {
1053 		ata_port_info(ap,
1054 			"PMP SError.N set for some ports, repeating recovery\n");
1055 		goto retry;
1056 	}
1057 
1058 	return 0;
1059 
1060  link_fail:
1061 	if (sata_pmp_handle_link_fail(link, link_tries)) {
1062 		pmp_ehc->i.action |= ATA_EH_RESET;
1063 		goto retry;
1064 	}
1065 
1066 	/* fall through */
1067  pmp_fail:
1068 	/* Control always ends up here after detaching PMP.  Shut up
1069 	 * and return if we're unloading.
1070 	 */
1071 	if (ap->pflags & ATA_PFLAG_UNLOADING)
1072 		return rc;
1073 
1074 	if (!sata_pmp_attached(ap))
1075 		goto retry;
1076 
1077 	if (--pmp_tries) {
1078 		pmp_ehc->i.action |= ATA_EH_RESET;
1079 		goto retry;
1080 	}
1081 
1082 	ata_port_err(ap, "failed to recover PMP after %d tries, giving up\n",
1083 		     ATA_EH_PMP_TRIES);
1084 	sata_pmp_detach(pmp_dev);
1085 	ata_dev_disable(pmp_dev);
1086 
1087 	return rc;
1088 }
1089 
1090 /**
1091  *	sata_pmp_error_handler - do standard error handling for PMP-enabled host
1092  *	@ap: host port to handle error for
1093  *
1094  *	Perform standard error handling sequence for PMP-enabled host
1095  *	@ap.
1096  *
1097  *	LOCKING:
1098  *	Kernel thread context (may sleep).
1099  */
1100 void sata_pmp_error_handler(struct ata_port *ap)
1101 {
1102 	ata_eh_autopsy(ap);
1103 	ata_eh_report(ap);
1104 	sata_pmp_eh_recover(ap);
1105 	ata_eh_finish(ap);
1106 }
1107 
1108 EXPORT_SYMBOL_GPL(sata_pmp_port_ops);
1109 EXPORT_SYMBOL_GPL(sata_pmp_qc_defer_cmd_switch);
1110 EXPORT_SYMBOL_GPL(sata_pmp_error_handler);
1111