xref: /openbmc/linux/drivers/ata/libata-pmp.c (revision 9a29f5fc)
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_prereset		= ata_std_prereset,
19 	.pmp_hardreset		= sata_std_hardreset,
20 	.pmp_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 
114 	if (ap->excl_link == NULL || ap->excl_link == link) {
115 		if (ap->nr_active_links == 0 || ata_link_active(link)) {
116 			qc->flags |= ATA_QCFLAG_CLEAR_EXCL;
117 			return ata_std_qc_defer(qc);
118 		}
119 
120 		ap->excl_link = link;
121 	}
122 
123 	return ATA_DEFER_PORT;
124 }
125 
126 /**
127  *	sata_pmp_scr_read - read PSCR
128  *	@link: ATA link to read PSCR for
129  *	@reg: PSCR to read
130  *	@r_val: resulting value
131  *
132  *	Read PSCR @reg into @r_val for @link, to be called from
133  *	ata_scr_read().
134  *
135  *	LOCKING:
136  *	Kernel thread context (may sleep).
137  *
138  *	RETURNS:
139  *	0 on success, -errno on failure.
140  */
141 int sata_pmp_scr_read(struct ata_link *link, int reg, u32 *r_val)
142 {
143 	unsigned int err_mask;
144 
145 	if (reg > SATA_PMP_PSCR_CONTROL)
146 		return -EINVAL;
147 
148 	err_mask = sata_pmp_read(link, reg, r_val);
149 	if (err_mask) {
150 		ata_link_warn(link, "failed to read SCR %d (Emask=0x%x)\n",
151 			      reg, err_mask);
152 		return -EIO;
153 	}
154 	return 0;
155 }
156 
157 /**
158  *	sata_pmp_scr_write - write PSCR
159  *	@link: ATA link to write PSCR for
160  *	@reg: PSCR to write
161  *	@val: value to be written
162  *
163  *	Write @val to PSCR @reg for @link, to be called from
164  *	ata_scr_write() and ata_scr_write_flush().
165  *
166  *	LOCKING:
167  *	Kernel thread context (may sleep).
168  *
169  *	RETURNS:
170  *	0 on success, -errno on failure.
171  */
172 int sata_pmp_scr_write(struct ata_link *link, int reg, u32 val)
173 {
174 	unsigned int err_mask;
175 
176 	if (reg > SATA_PMP_PSCR_CONTROL)
177 		return -EINVAL;
178 
179 	err_mask = sata_pmp_write(link, reg, val);
180 	if (err_mask) {
181 		ata_link_warn(link, "failed to write SCR %d (Emask=0x%x)\n",
182 			      reg, err_mask);
183 		return -EIO;
184 	}
185 	return 0;
186 }
187 
188 /**
189  *	sata_pmp_set_lpm - configure LPM for a PMP link
190  *	@link: PMP link to configure LPM for
191  *	@policy: target LPM policy
192  *	@hints: LPM hints
193  *
194  *	Configure LPM for @link.  This function will contain any PMP
195  *	specific workarounds if necessary.
196  *
197  *	LOCKING:
198  *	EH context.
199  *
200  *	RETURNS:
201  *	0 on success, -errno on failure.
202  */
203 int sata_pmp_set_lpm(struct ata_link *link, enum ata_lpm_policy policy,
204 		     unsigned hints)
205 {
206 	return sata_link_scr_lpm(link, policy, true);
207 }
208 
209 /**
210  *	sata_pmp_read_gscr - read GSCR block of SATA PMP
211  *	@dev: PMP device
212  *	@gscr: buffer to read GSCR block into
213  *
214  *	Read selected PMP GSCRs from the PMP at @dev.  This will serve
215  *	as configuration and identification info for the PMP.
216  *
217  *	LOCKING:
218  *	Kernel thread context (may sleep).
219  *
220  *	RETURNS:
221  *	0 on success, -errno on failure.
222  */
223 static int sata_pmp_read_gscr(struct ata_device *dev, u32 *gscr)
224 {
225 	static const int gscr_to_read[] = { 0, 1, 2, 32, 33, 64, 96 };
226 	int i;
227 
228 	for (i = 0; i < ARRAY_SIZE(gscr_to_read); i++) {
229 		int reg = gscr_to_read[i];
230 		unsigned int err_mask;
231 
232 		err_mask = sata_pmp_read(dev->link, reg, &gscr[reg]);
233 		if (err_mask) {
234 			ata_dev_err(dev, "failed to read PMP GSCR[%d] (Emask=0x%x)\n",
235 				    reg, err_mask);
236 			return -EIO;
237 		}
238 	}
239 
240 	return 0;
241 }
242 
243 static const char *sata_pmp_spec_rev_str(const u32 *gscr)
244 {
245 	u32 rev = gscr[SATA_PMP_GSCR_REV];
246 
247 	if (rev & (1 << 3))
248 		return "1.2";
249 	if (rev & (1 << 2))
250 		return "1.1";
251 	if (rev & (1 << 1))
252 		return "1.0";
253 	return "<unknown>";
254 }
255 
256 #define PMP_GSCR_SII_POL 129
257 
258 static int sata_pmp_configure(struct ata_device *dev, int print_info)
259 {
260 	struct ata_port *ap = dev->link->ap;
261 	u32 *gscr = dev->gscr;
262 	u16 vendor = sata_pmp_gscr_vendor(gscr);
263 	u16 devid = sata_pmp_gscr_devid(gscr);
264 	unsigned int err_mask = 0;
265 	const char *reason;
266 	int nr_ports, rc;
267 
268 	nr_ports = sata_pmp_gscr_ports(gscr);
269 
270 	if (nr_ports <= 0 || nr_ports > SATA_PMP_MAX_PORTS) {
271 		rc = -EINVAL;
272 		reason = "invalid nr_ports";
273 		goto fail;
274 	}
275 
276 	if ((ap->flags & ATA_FLAG_AN) &&
277 	    (gscr[SATA_PMP_GSCR_FEAT] & SATA_PMP_FEAT_NOTIFY))
278 		dev->flags |= ATA_DFLAG_AN;
279 
280 	/* monitor SERR_PHYRDY_CHG on fan-out ports */
281 	err_mask = sata_pmp_write(dev->link, SATA_PMP_GSCR_ERROR_EN,
282 				  SERR_PHYRDY_CHG);
283 	if (err_mask) {
284 		rc = -EIO;
285 		reason = "failed to write GSCR_ERROR_EN";
286 		goto fail;
287 	}
288 
289 	/* Disable sending Early R_OK.
290 	 * With "cached read" HDD testing and multiple ports busy on a SATA
291 	 * host controller, 3x26 PMP will very rarely drop a deferred
292 	 * R_OK that was intended for the host. Symptom will be all
293 	 * 5 drives under test will timeout, get reset, and recover.
294 	 */
295 	if (vendor == 0x1095 && (devid == 0x3726 || devid == 0x3826)) {
296 		u32 reg;
297 
298 		err_mask = sata_pmp_read(&ap->link, PMP_GSCR_SII_POL, &reg);
299 		if (err_mask) {
300 			rc = -EIO;
301 			reason = "failed to read Sil3x26 Private Register";
302 			goto fail;
303 		}
304 		reg &= ~0x1;
305 		err_mask = sata_pmp_write(&ap->link, PMP_GSCR_SII_POL, reg);
306 		if (err_mask) {
307 			rc = -EIO;
308 			reason = "failed to write Sil3x26 Private Register";
309 			goto fail;
310 		}
311 	}
312 
313 	if (print_info) {
314 		ata_dev_info(dev, "Port Multiplier %s, "
315 			     "0x%04x:0x%04x r%d, %d ports, feat 0x%x/0x%x\n",
316 			     sata_pmp_spec_rev_str(gscr), vendor, devid,
317 			     sata_pmp_gscr_rev(gscr),
318 			     nr_ports, gscr[SATA_PMP_GSCR_FEAT_EN],
319 			     gscr[SATA_PMP_GSCR_FEAT]);
320 
321 		if (!(dev->flags & ATA_DFLAG_AN))
322 			ata_dev_info(dev,
323 				"Asynchronous notification not supported, "
324 				"hotplug won't work on fan-out ports. Use warm-plug instead.\n");
325 	}
326 
327 	return 0;
328 
329  fail:
330 	ata_dev_err(dev,
331 		    "failed to configure Port Multiplier (%s, Emask=0x%x)\n",
332 		    reason, err_mask);
333 	return rc;
334 }
335 
336 static int sata_pmp_init_links (struct ata_port *ap, int nr_ports)
337 {
338 	struct ata_link *pmp_link = ap->pmp_link;
339 	int i, err;
340 
341 	if (!pmp_link) {
342 		pmp_link = kcalloc(SATA_PMP_MAX_PORTS, sizeof(pmp_link[0]),
343 				   GFP_NOIO);
344 		if (!pmp_link)
345 			return -ENOMEM;
346 
347 		for (i = 0; i < SATA_PMP_MAX_PORTS; i++)
348 			ata_link_init(ap, &pmp_link[i], i);
349 
350 		ap->pmp_link = pmp_link;
351 
352 		for (i = 0; i < SATA_PMP_MAX_PORTS; i++) {
353 			err = ata_tlink_add(&pmp_link[i]);
354 			if (err) {
355 				goto err_tlink;
356 			}
357 		}
358 	}
359 
360 	for (i = 0; i < nr_ports; i++) {
361 		struct ata_link *link = &pmp_link[i];
362 		struct ata_eh_context *ehc = &link->eh_context;
363 
364 		link->flags = 0;
365 		ehc->i.probe_mask |= ATA_ALL_DEVICES;
366 		ehc->i.action |= ATA_EH_RESET;
367 	}
368 
369 	return 0;
370   err_tlink:
371 	while (--i >= 0)
372 		ata_tlink_delete(&pmp_link[i]);
373 	kfree(pmp_link);
374 	ap->pmp_link = NULL;
375 	return err;
376 }
377 
378 static void sata_pmp_quirks(struct ata_port *ap)
379 {
380 	u32 *gscr = ap->link.device->gscr;
381 	u16 vendor = sata_pmp_gscr_vendor(gscr);
382 	u16 devid = sata_pmp_gscr_devid(gscr);
383 	struct ata_link *link;
384 
385 	if (vendor == 0x1095 && (devid == 0x3726 || devid == 0x3826)) {
386 		/* sil3x26 quirks */
387 		ata_for_each_link(link, ap, EDGE) {
388 			/* link reports offline after LPM */
389 			link->flags |= ATA_LFLAG_NO_LPM;
390 
391 			/*
392 			 * Class code report is unreliable and SRST times
393 			 * out under certain configurations.
394 			 */
395 			if (link->pmp < 5)
396 				link->flags |= ATA_LFLAG_NO_SRST |
397 					       ATA_LFLAG_ASSUME_ATA;
398 
399 			/* port 5 is for SEMB device and it doesn't like SRST */
400 			if (link->pmp == 5)
401 				link->flags |= ATA_LFLAG_NO_SRST |
402 					       ATA_LFLAG_ASSUME_SEMB;
403 		}
404 	} else if (vendor == 0x1095 && devid == 0x4723) {
405 		/*
406 		 * sil4723 quirks
407 		 *
408 		 * Link reports offline after LPM.  Class code report is
409 		 * unreliable.  SIMG PMPs never got SRST reliable and the
410 		 * config device at port 2 locks up on SRST.
411 		 */
412 		ata_for_each_link(link, ap, EDGE)
413 			link->flags |= ATA_LFLAG_NO_LPM |
414 				       ATA_LFLAG_NO_SRST |
415 				       ATA_LFLAG_ASSUME_ATA;
416 	} else if (vendor == 0x1095 && devid == 0x4726) {
417 		/* sil4726 quirks */
418 		ata_for_each_link(link, ap, EDGE) {
419 			/* link reports offline after LPM */
420 			link->flags |= ATA_LFLAG_NO_LPM;
421 
422 			/* Class code report is unreliable and SRST
423 			 * times out under certain configurations.
424 			 * Config device can be at port 0 or 5 and
425 			 * locks up on SRST.
426 			 */
427 			if (link->pmp <= 5)
428 				link->flags |= ATA_LFLAG_NO_SRST |
429 					       ATA_LFLAG_ASSUME_ATA;
430 
431 			/* Port 6 is for SEMB device which doesn't
432 			 * like SRST either.
433 			 */
434 			if (link->pmp == 6)
435 				link->flags |= ATA_LFLAG_NO_SRST |
436 					       ATA_LFLAG_ASSUME_SEMB;
437 		}
438 	} else if (vendor == 0x1095 && (devid == 0x5723 || devid == 0x5733 ||
439 					devid == 0x5734 || devid == 0x5744)) {
440 		/* sil5723/5744 quirks */
441 
442 		/* sil5723/5744 has either two or three downstream
443 		 * ports depending on operation mode.  The last port
444 		 * is empty if any actual IO device is available or
445 		 * occupied by a pseudo configuration device
446 		 * otherwise.  Don't try hard to recover it.
447 		 */
448 		ap->pmp_link[ap->nr_pmp_links - 1].flags |= ATA_LFLAG_NO_RETRY;
449 	} else if (vendor == 0x197b && (devid == 0x2352 || devid == 0x0325)) {
450 		/*
451 		 * 0x2352: found in Thermaltake BlackX Duet, jmicron JMB350?
452 		 * 0x0325: jmicron JMB394.
453 		 */
454 		ata_for_each_link(link, ap, EDGE) {
455 			/* SRST breaks detection and disks get misclassified
456 			 * LPM disabled to avoid potential problems
457 			 */
458 			link->flags |= ATA_LFLAG_NO_LPM |
459 				       ATA_LFLAG_NO_SRST |
460 				       ATA_LFLAG_ASSUME_ATA;
461 		}
462 	} else if (vendor == 0x11ab && devid == 0x4140) {
463 		/* Marvell 4140 quirks */
464 		ata_for_each_link(link, ap, EDGE) {
465 			/* port 4 is for SEMB device and it doesn't like SRST */
466 			if (link->pmp == 4)
467 				link->flags |= ATA_LFLAG_DISABLED;
468 		}
469 	}
470 }
471 
472 /**
473  *	sata_pmp_attach - attach a SATA PMP device
474  *	@dev: SATA PMP device to attach
475  *
476  *	Configure and attach SATA PMP device @dev.  This function is
477  *	also responsible for allocating and initializing PMP links.
478  *
479  *	LOCKING:
480  *	Kernel thread context (may sleep).
481  *
482  *	RETURNS:
483  *	0 on success, -errno on failure.
484  */
485 int sata_pmp_attach(struct ata_device *dev)
486 {
487 	struct ata_link *link = dev->link;
488 	struct ata_port *ap = link->ap;
489 	unsigned long flags;
490 	struct ata_link *tlink;
491 	int rc;
492 
493 	/* is it hanging off the right place? */
494 	if (!sata_pmp_supported(ap)) {
495 		ata_dev_err(dev, "host does not support Port Multiplier\n");
496 		return -EINVAL;
497 	}
498 
499 	if (!ata_is_host_link(link)) {
500 		ata_dev_err(dev, "Port Multipliers cannot be nested\n");
501 		return -EINVAL;
502 	}
503 
504 	if (dev->devno) {
505 		ata_dev_err(dev, "Port Multiplier must be the first device\n");
506 		return -EINVAL;
507 	}
508 
509 	WARN_ON(link->pmp != 0);
510 	link->pmp = SATA_PMP_CTRL_PORT;
511 
512 	/* read GSCR block */
513 	rc = sata_pmp_read_gscr(dev, dev->gscr);
514 	if (rc)
515 		goto fail;
516 
517 	/* config PMP */
518 	rc = sata_pmp_configure(dev, 1);
519 	if (rc)
520 		goto fail;
521 
522 	rc = sata_pmp_init_links(ap, sata_pmp_gscr_ports(dev->gscr));
523 	if (rc) {
524 		ata_dev_info(dev, "failed to initialize PMP links\n");
525 		goto fail;
526 	}
527 
528 	/* attach it */
529 	spin_lock_irqsave(ap->lock, flags);
530 	WARN_ON(ap->nr_pmp_links);
531 	ap->nr_pmp_links = sata_pmp_gscr_ports(dev->gscr);
532 	spin_unlock_irqrestore(ap->lock, flags);
533 
534 	sata_pmp_quirks(ap);
535 
536 	if (ap->ops->pmp_attach)
537 		ap->ops->pmp_attach(ap);
538 
539 	ata_for_each_link(tlink, ap, EDGE)
540 		sata_link_init_spd(tlink);
541 
542 	return 0;
543 
544  fail:
545 	link->pmp = 0;
546 	return rc;
547 }
548 
549 /**
550  *	sata_pmp_detach - detach a SATA PMP device
551  *	@dev: SATA PMP device to detach
552  *
553  *	Detach SATA PMP device @dev.  This function is also
554  *	responsible for deconfiguring PMP links.
555  *
556  *	LOCKING:
557  *	Kernel thread context (may sleep).
558  */
559 static void sata_pmp_detach(struct ata_device *dev)
560 {
561 	struct ata_link *link = dev->link;
562 	struct ata_port *ap = link->ap;
563 	struct ata_link *tlink;
564 	unsigned long flags;
565 
566 	ata_dev_info(dev, "Port Multiplier detaching\n");
567 
568 	WARN_ON(!ata_is_host_link(link) || dev->devno ||
569 		link->pmp != SATA_PMP_CTRL_PORT);
570 
571 	if (ap->ops->pmp_detach)
572 		ap->ops->pmp_detach(ap);
573 
574 	ata_for_each_link(tlink, ap, EDGE)
575 		ata_eh_detach_dev(tlink->device);
576 
577 	spin_lock_irqsave(ap->lock, flags);
578 	ap->nr_pmp_links = 0;
579 	link->pmp = 0;
580 	spin_unlock_irqrestore(ap->lock, flags);
581 }
582 
583 /**
584  *	sata_pmp_same_pmp - does new GSCR matches the configured PMP?
585  *	@dev: PMP device to compare against
586  *	@new_gscr: GSCR block of the new device
587  *
588  *	Compare @new_gscr against @dev and determine whether @dev is
589  *	the PMP described by @new_gscr.
590  *
591  *	LOCKING:
592  *	None.
593  *
594  *	RETURNS:
595  *	1 if @dev matches @new_gscr, 0 otherwise.
596  */
597 static int sata_pmp_same_pmp(struct ata_device *dev, const u32 *new_gscr)
598 {
599 	const u32 *old_gscr = dev->gscr;
600 	u16 old_vendor, new_vendor, old_devid, new_devid;
601 	int old_nr_ports, new_nr_ports;
602 
603 	old_vendor = sata_pmp_gscr_vendor(old_gscr);
604 	new_vendor = sata_pmp_gscr_vendor(new_gscr);
605 	old_devid = sata_pmp_gscr_devid(old_gscr);
606 	new_devid = sata_pmp_gscr_devid(new_gscr);
607 	old_nr_ports = sata_pmp_gscr_ports(old_gscr);
608 	new_nr_ports = sata_pmp_gscr_ports(new_gscr);
609 
610 	if (old_vendor != new_vendor) {
611 		ata_dev_info(dev,
612 			     "Port Multiplier vendor mismatch '0x%x' != '0x%x'\n",
613 			     old_vendor, new_vendor);
614 		return 0;
615 	}
616 
617 	if (old_devid != new_devid) {
618 		ata_dev_info(dev,
619 			     "Port Multiplier device ID mismatch '0x%x' != '0x%x'\n",
620 			     old_devid, new_devid);
621 		return 0;
622 	}
623 
624 	if (old_nr_ports != new_nr_ports) {
625 		ata_dev_info(dev,
626 			     "Port Multiplier nr_ports mismatch '0x%x' != '0x%x'\n",
627 			     old_nr_ports, new_nr_ports);
628 		return 0;
629 	}
630 
631 	return 1;
632 }
633 
634 /**
635  *	sata_pmp_revalidate - revalidate SATA PMP
636  *	@dev: PMP device to revalidate
637  *	@new_class: new class code
638  *
639  *	Re-read GSCR block and make sure @dev is still attached to the
640  *	port and properly configured.
641  *
642  *	LOCKING:
643  *	Kernel thread context (may sleep).
644  *
645  *	RETURNS:
646  *	0 on success, -errno otherwise.
647  */
648 static int sata_pmp_revalidate(struct ata_device *dev, unsigned int new_class)
649 {
650 	struct ata_link *link = dev->link;
651 	struct ata_port *ap = link->ap;
652 	u32 *gscr = (void *)ap->sector_buf;
653 	int rc;
654 
655 	ata_eh_about_to_do(link, NULL, ATA_EH_REVALIDATE);
656 
657 	if (!ata_dev_enabled(dev)) {
658 		rc = -ENODEV;
659 		goto fail;
660 	}
661 
662 	/* wrong class? */
663 	if (ata_class_enabled(new_class) && new_class != ATA_DEV_PMP) {
664 		rc = -ENODEV;
665 		goto fail;
666 	}
667 
668 	/* read GSCR */
669 	rc = sata_pmp_read_gscr(dev, gscr);
670 	if (rc)
671 		goto fail;
672 
673 	/* is the pmp still there? */
674 	if (!sata_pmp_same_pmp(dev, gscr)) {
675 		rc = -ENODEV;
676 		goto fail;
677 	}
678 
679 	memcpy(dev->gscr, gscr, sizeof(gscr[0]) * SATA_PMP_GSCR_DWORDS);
680 
681 	rc = sata_pmp_configure(dev, 0);
682 	if (rc)
683 		goto fail;
684 
685 	ata_eh_done(link, NULL, ATA_EH_REVALIDATE);
686 
687 	return 0;
688 
689  fail:
690 	ata_dev_err(dev, "PMP revalidation failed (errno=%d)\n", rc);
691 	return rc;
692 }
693 
694 /**
695  *	sata_pmp_revalidate_quick - revalidate SATA PMP quickly
696  *	@dev: PMP device to revalidate
697  *
698  *	Make sure the attached PMP is accessible.
699  *
700  *	LOCKING:
701  *	Kernel thread context (may sleep).
702  *
703  *	RETURNS:
704  *	0 on success, -errno otherwise.
705  */
706 static int sata_pmp_revalidate_quick(struct ata_device *dev)
707 {
708 	unsigned int err_mask;
709 	u32 prod_id;
710 
711 	err_mask = sata_pmp_read(dev->link, SATA_PMP_GSCR_PROD_ID, &prod_id);
712 	if (err_mask) {
713 		ata_dev_err(dev,
714 			    "failed to read PMP product ID (Emask=0x%x)\n",
715 			    err_mask);
716 		return -EIO;
717 	}
718 
719 	if (prod_id != dev->gscr[SATA_PMP_GSCR_PROD_ID]) {
720 		ata_dev_err(dev, "PMP product ID mismatch\n");
721 		/* something weird is going on, request full PMP recovery */
722 		return -EIO;
723 	}
724 
725 	return 0;
726 }
727 
728 /**
729  *	sata_pmp_eh_recover_pmp - recover PMP
730  *	@ap: ATA port PMP is attached to
731  *	@prereset: prereset method (can be NULL)
732  *	@softreset: softreset method
733  *	@hardreset: hardreset method
734  *	@postreset: postreset method (can be NULL)
735  *
736  *	Recover PMP attached to @ap.  Recovery procedure is somewhat
737  *	similar to that of ata_eh_recover() except that reset should
738  *	always be performed in hard->soft sequence and recovery
739  *	failure results in PMP detachment.
740  *
741  *	LOCKING:
742  *	Kernel thread context (may sleep).
743  *
744  *	RETURNS:
745  *	0 on success, -errno on failure.
746  */
747 static int sata_pmp_eh_recover_pmp(struct ata_port *ap,
748 		ata_prereset_fn_t prereset, ata_reset_fn_t softreset,
749 		ata_reset_fn_t hardreset, ata_postreset_fn_t postreset)
750 {
751 	struct ata_link *link = &ap->link;
752 	struct ata_eh_context *ehc = &link->eh_context;
753 	struct ata_device *dev = link->device;
754 	int tries = ATA_EH_PMP_TRIES;
755 	int detach = 0, rc = 0;
756 	int reval_failed = 0;
757 
758 	if (dev->flags & ATA_DFLAG_DETACH) {
759 		detach = 1;
760 		rc = -ENODEV;
761 		goto fail;
762 	}
763 
764  retry:
765 	ehc->classes[0] = ATA_DEV_UNKNOWN;
766 
767 	if (ehc->i.action & ATA_EH_RESET) {
768 		struct ata_link *tlink;
769 
770 		/* reset */
771 		rc = ata_eh_reset(link, 0, prereset, softreset, hardreset,
772 				  postreset);
773 		if (rc) {
774 			ata_link_err(link, "failed to reset PMP, giving up\n");
775 			goto fail;
776 		}
777 
778 		/* PMP is reset, SErrors cannot be trusted, scan all */
779 		ata_for_each_link(tlink, ap, EDGE) {
780 			struct ata_eh_context *ehc = &tlink->eh_context;
781 
782 			ehc->i.probe_mask |= ATA_ALL_DEVICES;
783 			ehc->i.action |= ATA_EH_RESET;
784 		}
785 	}
786 
787 	/* If revalidation is requested, revalidate and reconfigure;
788 	 * otherwise, do quick revalidation.
789 	 */
790 	if (ehc->i.action & ATA_EH_REVALIDATE)
791 		rc = sata_pmp_revalidate(dev, ehc->classes[0]);
792 	else
793 		rc = sata_pmp_revalidate_quick(dev);
794 
795 	if (rc) {
796 		tries--;
797 
798 		if (rc == -ENODEV) {
799 			ehc->i.probe_mask |= ATA_ALL_DEVICES;
800 			detach = 1;
801 			/* give it just two more chances */
802 			tries = min(tries, 2);
803 		}
804 
805 		if (tries) {
806 			/* consecutive revalidation failures? speed down */
807 			if (reval_failed)
808 				sata_down_spd_limit(link, 0);
809 			else
810 				reval_failed = 1;
811 
812 			ehc->i.action |= ATA_EH_RESET;
813 			goto retry;
814 		} else {
815 			ata_dev_err(dev,
816 				    "failed to recover PMP after %d tries, giving up\n",
817 				    ATA_EH_PMP_TRIES);
818 			goto fail;
819 		}
820 	}
821 
822 	/* okay, PMP resurrected */
823 	ehc->i.flags = 0;
824 
825 	return 0;
826 
827  fail:
828 	sata_pmp_detach(dev);
829 	if (detach)
830 		ata_eh_detach_dev(dev);
831 	else
832 		ata_dev_disable(dev);
833 
834 	return rc;
835 }
836 
837 static int sata_pmp_eh_handle_disabled_links(struct ata_port *ap)
838 {
839 	struct ata_link *link;
840 	unsigned long flags;
841 	int rc;
842 
843 	spin_lock_irqsave(ap->lock, flags);
844 
845 	ata_for_each_link(link, ap, EDGE) {
846 		if (!(link->flags & ATA_LFLAG_DISABLED))
847 			continue;
848 
849 		spin_unlock_irqrestore(ap->lock, flags);
850 
851 		/* Some PMPs require hardreset sequence to get
852 		 * SError.N working.
853 		 */
854 		sata_link_hardreset(link, sata_deb_timing_normal,
855 				ata_deadline(jiffies, ATA_TMOUT_INTERNAL_QUICK),
856 				NULL, NULL);
857 
858 		/* unconditionally clear SError.N */
859 		rc = sata_scr_write(link, SCR_ERROR, SERR_PHYRDY_CHG);
860 		if (rc) {
861 			ata_link_err(link,
862 				     "failed to clear SError.N (errno=%d)\n",
863 				     rc);
864 			return rc;
865 		}
866 
867 		spin_lock_irqsave(ap->lock, flags);
868 	}
869 
870 	spin_unlock_irqrestore(ap->lock, flags);
871 
872 	return 0;
873 }
874 
875 static int sata_pmp_handle_link_fail(struct ata_link *link, int *link_tries)
876 {
877 	struct ata_port *ap = link->ap;
878 	unsigned long flags;
879 
880 	if (link_tries[link->pmp] && --link_tries[link->pmp])
881 		return 1;
882 
883 	/* disable this link */
884 	if (!(link->flags & ATA_LFLAG_DISABLED)) {
885 		ata_link_warn(link,
886 			"failed to recover link after %d tries, disabling\n",
887 			ATA_EH_PMP_LINK_TRIES);
888 
889 		spin_lock_irqsave(ap->lock, flags);
890 		link->flags |= ATA_LFLAG_DISABLED;
891 		spin_unlock_irqrestore(ap->lock, flags);
892 	}
893 
894 	ata_dev_disable(link->device);
895 	link->eh_context.i.action = 0;
896 
897 	return 0;
898 }
899 
900 /**
901  *	sata_pmp_eh_recover - recover PMP-enabled port
902  *	@ap: ATA port to recover
903  *
904  *	Drive EH recovery operation for PMP enabled port @ap.  This
905  *	function recovers host and PMP ports with proper retrials and
906  *	fallbacks.  Actual recovery operations are performed using
907  *	ata_eh_recover() and sata_pmp_eh_recover_pmp().
908  *
909  *	LOCKING:
910  *	Kernel thread context (may sleep).
911  *
912  *	RETURNS:
913  *	0 on success, -errno on failure.
914  */
915 static int sata_pmp_eh_recover(struct ata_port *ap)
916 {
917 	struct ata_port_operations *ops = ap->ops;
918 	int pmp_tries, link_tries[SATA_PMP_MAX_PORTS];
919 	struct ata_link *pmp_link = &ap->link;
920 	struct ata_device *pmp_dev = pmp_link->device;
921 	struct ata_eh_context *pmp_ehc = &pmp_link->eh_context;
922 	u32 *gscr = pmp_dev->gscr;
923 	struct ata_link *link;
924 	struct ata_device *dev;
925 	unsigned int err_mask;
926 	u32 gscr_error, sntf;
927 	int cnt, rc;
928 
929 	pmp_tries = ATA_EH_PMP_TRIES;
930 	ata_for_each_link(link, ap, EDGE)
931 		link_tries[link->pmp] = ATA_EH_PMP_LINK_TRIES;
932 
933  retry:
934 	/* PMP attached? */
935 	if (!sata_pmp_attached(ap)) {
936 		rc = ata_eh_recover(ap, ops->prereset, ops->softreset,
937 				    ops->hardreset, ops->postreset, NULL);
938 		if (rc) {
939 			ata_for_each_dev(dev, &ap->link, ALL)
940 				ata_dev_disable(dev);
941 			return rc;
942 		}
943 
944 		if (pmp_dev->class != ATA_DEV_PMP)
945 			return 0;
946 
947 		/* new PMP online */
948 		ata_for_each_link(link, ap, EDGE)
949 			link_tries[link->pmp] = ATA_EH_PMP_LINK_TRIES;
950 
951 		/* fall through */
952 	}
953 
954 	/* recover pmp */
955 	rc = sata_pmp_eh_recover_pmp(ap, ops->prereset, ops->softreset,
956 				     ops->hardreset, ops->postreset);
957 	if (rc)
958 		goto pmp_fail;
959 
960 	/* PHY event notification can disturb reset and other recovery
961 	 * operations.  Turn it off.
962 	 */
963 	if (gscr[SATA_PMP_GSCR_FEAT_EN] & SATA_PMP_FEAT_NOTIFY) {
964 		gscr[SATA_PMP_GSCR_FEAT_EN] &= ~SATA_PMP_FEAT_NOTIFY;
965 
966 		err_mask = sata_pmp_write(pmp_link, SATA_PMP_GSCR_FEAT_EN,
967 					  gscr[SATA_PMP_GSCR_FEAT_EN]);
968 		if (err_mask) {
969 			ata_link_warn(pmp_link,
970 				"failed to disable NOTIFY (err_mask=0x%x)\n",
971 				err_mask);
972 			goto pmp_fail;
973 		}
974 	}
975 
976 	/* handle disabled links */
977 	rc = sata_pmp_eh_handle_disabled_links(ap);
978 	if (rc)
979 		goto pmp_fail;
980 
981 	/* recover links */
982 	rc = ata_eh_recover(ap, ops->pmp_prereset, ops->pmp_softreset,
983 			    ops->pmp_hardreset, ops->pmp_postreset, &link);
984 	if (rc)
985 		goto link_fail;
986 
987 	/* clear SNotification */
988 	rc = sata_scr_read(&ap->link, SCR_NOTIFICATION, &sntf);
989 	if (rc == 0)
990 		sata_scr_write(&ap->link, SCR_NOTIFICATION, sntf);
991 
992 	/*
993 	 * If LPM is active on any fan-out port, hotplug wouldn't
994 	 * work.  Return w/ PHY event notification disabled.
995 	 */
996 	ata_for_each_link(link, ap, EDGE)
997 		if (link->lpm_policy > ATA_LPM_MAX_POWER)
998 			return 0;
999 
1000 	/*
1001 	 * Connection status might have changed while resetting other
1002 	 * links, enable notification and check SATA_PMP_GSCR_ERROR
1003 	 * before returning.
1004 	 */
1005 
1006 	/* enable notification */
1007 	if (pmp_dev->flags & ATA_DFLAG_AN) {
1008 		gscr[SATA_PMP_GSCR_FEAT_EN] |= SATA_PMP_FEAT_NOTIFY;
1009 
1010 		err_mask = sata_pmp_write(pmp_link, SATA_PMP_GSCR_FEAT_EN,
1011 					  gscr[SATA_PMP_GSCR_FEAT_EN]);
1012 		if (err_mask) {
1013 			ata_dev_err(pmp_dev,
1014 				    "failed to write PMP_FEAT_EN (Emask=0x%x)\n",
1015 				    err_mask);
1016 			rc = -EIO;
1017 			goto pmp_fail;
1018 		}
1019 	}
1020 
1021 	/* check GSCR_ERROR */
1022 	err_mask = sata_pmp_read(pmp_link, SATA_PMP_GSCR_ERROR, &gscr_error);
1023 	if (err_mask) {
1024 		ata_dev_err(pmp_dev,
1025 			    "failed to read PMP_GSCR_ERROR (Emask=0x%x)\n",
1026 			    err_mask);
1027 		rc = -EIO;
1028 		goto pmp_fail;
1029 	}
1030 
1031 	cnt = 0;
1032 	ata_for_each_link(link, ap, EDGE) {
1033 		if (!(gscr_error & (1 << link->pmp)))
1034 			continue;
1035 
1036 		if (sata_pmp_handle_link_fail(link, link_tries)) {
1037 			ata_ehi_hotplugged(&link->eh_context.i);
1038 			cnt++;
1039 		} else {
1040 			ata_link_warn(link,
1041 				"PHY status changed but maxed out on retries, giving up\n");
1042 			ata_link_warn(link,
1043 				"Manually issue scan to resume this link\n");
1044 		}
1045 	}
1046 
1047 	if (cnt) {
1048 		ata_port_info(ap,
1049 			"PMP SError.N set for some ports, repeating recovery\n");
1050 		goto retry;
1051 	}
1052 
1053 	return 0;
1054 
1055  link_fail:
1056 	if (sata_pmp_handle_link_fail(link, link_tries)) {
1057 		pmp_ehc->i.action |= ATA_EH_RESET;
1058 		goto retry;
1059 	}
1060 
1061 	/* fall through */
1062  pmp_fail:
1063 	/* Control always ends up here after detaching PMP.  Shut up
1064 	 * and return if we're unloading.
1065 	 */
1066 	if (ap->pflags & ATA_PFLAG_UNLOADING)
1067 		return rc;
1068 
1069 	if (!sata_pmp_attached(ap))
1070 		goto retry;
1071 
1072 	if (--pmp_tries) {
1073 		pmp_ehc->i.action |= ATA_EH_RESET;
1074 		goto retry;
1075 	}
1076 
1077 	ata_port_err(ap, "failed to recover PMP after %d tries, giving up\n",
1078 		     ATA_EH_PMP_TRIES);
1079 	sata_pmp_detach(pmp_dev);
1080 	ata_dev_disable(pmp_dev);
1081 
1082 	return rc;
1083 }
1084 
1085 /**
1086  *	sata_pmp_error_handler - do standard error handling for PMP-enabled host
1087  *	@ap: host port to handle error for
1088  *
1089  *	Perform standard error handling sequence for PMP-enabled host
1090  *	@ap.
1091  *
1092  *	LOCKING:
1093  *	Kernel thread context (may sleep).
1094  */
1095 void sata_pmp_error_handler(struct ata_port *ap)
1096 {
1097 	ata_eh_autopsy(ap);
1098 	ata_eh_report(ap);
1099 	sata_pmp_eh_recover(ap);
1100 	ata_eh_finish(ap);
1101 }
1102 
1103 EXPORT_SYMBOL_GPL(sata_pmp_port_ops);
1104 EXPORT_SYMBOL_GPL(sata_pmp_qc_defer_cmd_switch);
1105 EXPORT_SYMBOL_GPL(sata_pmp_error_handler);
1106