xref: /openbmc/linux/drivers/ata/libata-pmp.c (revision a1e58bbd)
1 /*
2  * libata-pmp.c - libata port multiplier support
3  *
4  * Copyright (c) 2007  SUSE Linux Products GmbH
5  * Copyright (c) 2007  Tejun Heo <teheo@suse.de>
6  *
7  * This file is released under the GPLv2.
8  */
9 
10 #include <linux/kernel.h>
11 #include <linux/libata.h>
12 #include "libata.h"
13 
14 /**
15  *	sata_pmp_read - read PMP register
16  *	@link: link to read PMP register for
17  *	@reg: register to read
18  *	@r_val: resulting value
19  *
20  *	Read PMP register.
21  *
22  *	LOCKING:
23  *	Kernel thread context (may sleep).
24  *
25  *	RETURNS:
26  *	0 on success, AC_ERR_* mask on failure.
27  */
28 static unsigned int sata_pmp_read(struct ata_link *link, int reg, u32 *r_val)
29 {
30 	struct ata_port *ap = link->ap;
31 	struct ata_device *pmp_dev = ap->link.device;
32 	struct ata_taskfile tf;
33 	unsigned int err_mask;
34 
35 	ata_tf_init(pmp_dev, &tf);
36 	tf.command = ATA_CMD_PMP_READ;
37 	tf.protocol = ATA_PROT_NODATA;
38 	tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE | ATA_TFLAG_LBA48;
39 	tf.feature = reg;
40 	tf.device = link->pmp;
41 
42 	err_mask = ata_exec_internal(pmp_dev, &tf, NULL, DMA_NONE, NULL, 0,
43 				     SATA_PMP_SCR_TIMEOUT);
44 	if (err_mask)
45 		return err_mask;
46 
47 	*r_val = tf.nsect | tf.lbal << 8 | tf.lbam << 16 | tf.lbah << 24;
48 	return 0;
49 }
50 
51 /**
52  *	sata_pmp_write - write PMP register
53  *	@link: link to write PMP register for
54  *	@reg: register to write
55  *	@r_val: value to write
56  *
57  *	Write PMP register.
58  *
59  *	LOCKING:
60  *	Kernel thread context (may sleep).
61  *
62  *	RETURNS:
63  *	0 on success, AC_ERR_* mask on failure.
64  */
65 static unsigned int sata_pmp_write(struct ata_link *link, int reg, u32 val)
66 {
67 	struct ata_port *ap = link->ap;
68 	struct ata_device *pmp_dev = ap->link.device;
69 	struct ata_taskfile tf;
70 
71 	ata_tf_init(pmp_dev, &tf);
72 	tf.command = ATA_CMD_PMP_WRITE;
73 	tf.protocol = ATA_PROT_NODATA;
74 	tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE | ATA_TFLAG_LBA48;
75 	tf.feature = reg;
76 	tf.device = link->pmp;
77 	tf.nsect = val & 0xff;
78 	tf.lbal = (val >> 8) & 0xff;
79 	tf.lbam = (val >> 16) & 0xff;
80 	tf.lbah = (val >> 24) & 0xff;
81 
82 	return ata_exec_internal(pmp_dev, &tf, NULL, DMA_NONE, NULL, 0,
83 				 SATA_PMP_SCR_TIMEOUT);
84 }
85 
86 /**
87  *	sata_pmp_qc_defer_cmd_switch - qc_defer for command switching PMP
88  *	@qc: ATA command in question
89  *
90  *	A host which has command switching PMP support cannot issue
91  *	commands to multiple links simultaneously.
92  *
93  *	LOCKING:
94  *	spin_lock_irqsave(host lock)
95  *
96  *	RETURNS:
97  *	ATA_DEFER_* if deferring is needed, 0 otherwise.
98  */
99 int sata_pmp_qc_defer_cmd_switch(struct ata_queued_cmd *qc)
100 {
101 	struct ata_link *link = qc->dev->link;
102 	struct ata_port *ap = link->ap;
103 
104 	if (ap->excl_link == NULL || ap->excl_link == link) {
105 		if (ap->nr_active_links == 0 || ata_link_active(link)) {
106 			qc->flags |= ATA_QCFLAG_CLEAR_EXCL;
107 			return ata_std_qc_defer(qc);
108 		}
109 
110 		ap->excl_link = link;
111 	}
112 
113 	return ATA_DEFER_PORT;
114 }
115 
116 /**
117  *	sata_pmp_scr_read - read PSCR
118  *	@link: ATA link to read PSCR for
119  *	@reg: PSCR to read
120  *	@r_val: resulting value
121  *
122  *	Read PSCR @reg into @r_val for @link, to be called from
123  *	ata_scr_read().
124  *
125  *	LOCKING:
126  *	Kernel thread context (may sleep).
127  *
128  *	RETURNS:
129  *	0 on success, -errno on failure.
130  */
131 int sata_pmp_scr_read(struct ata_link *link, int reg, u32 *r_val)
132 {
133 	unsigned int err_mask;
134 
135 	if (reg > SATA_PMP_PSCR_CONTROL)
136 		return -EINVAL;
137 
138 	err_mask = sata_pmp_read(link, reg, r_val);
139 	if (err_mask) {
140 		ata_link_printk(link, KERN_WARNING, "failed to read SCR %d "
141 				"(Emask=0x%x)\n", reg, err_mask);
142 		return -EIO;
143 	}
144 	return 0;
145 }
146 
147 /**
148  *	sata_pmp_scr_write - write PSCR
149  *	@link: ATA link to write PSCR for
150  *	@reg: PSCR to write
151  *	@val: value to be written
152  *
153  *	Write @val to PSCR @reg for @link, to be called from
154  *	ata_scr_write() and ata_scr_write_flush().
155  *
156  *	LOCKING:
157  *	Kernel thread context (may sleep).
158  *
159  *	RETURNS:
160  *	0 on success, -errno on failure.
161  */
162 int sata_pmp_scr_write(struct ata_link *link, int reg, u32 val)
163 {
164 	unsigned int err_mask;
165 
166 	if (reg > SATA_PMP_PSCR_CONTROL)
167 		return -EINVAL;
168 
169 	err_mask = sata_pmp_write(link, reg, val);
170 	if (err_mask) {
171 		ata_link_printk(link, KERN_WARNING, "failed to write SCR %d "
172 				"(Emask=0x%x)\n", reg, err_mask);
173 		return -EIO;
174 	}
175 	return 0;
176 }
177 
178 /**
179  *	sata_pmp_std_prereset - prepare PMP link for reset
180  *	@link: link to be reset
181  *	@deadline: deadline jiffies for the operation
182  *
183  *	@link is about to be reset.  Initialize it.
184  *
185  *	LOCKING:
186  *	Kernel thread context (may sleep)
187  *
188  *	RETURNS:
189  *	0 on success, -errno otherwise.
190  */
191 int sata_pmp_std_prereset(struct ata_link *link, unsigned long deadline)
192 {
193 	struct ata_eh_context *ehc = &link->eh_context;
194 	const unsigned long *timing = sata_ehc_deb_timing(ehc);
195 	int rc;
196 
197 	/* force HRST? */
198 	if (link->flags & ATA_LFLAG_NO_SRST)
199 		ehc->i.action |= ATA_EH_HARDRESET;
200 
201 	/* handle link resume */
202 	if ((ehc->i.flags & ATA_EHI_RESUME_LINK) &&
203 	    (link->flags & ATA_LFLAG_HRST_TO_RESUME))
204 		ehc->i.action |= ATA_EH_HARDRESET;
205 
206 	/* if we're about to do hardreset, nothing more to do */
207 	if (ehc->i.action & ATA_EH_HARDRESET)
208 		return 0;
209 
210 	/* resume link */
211 	rc = sata_link_resume(link, timing, deadline);
212 	if (rc) {
213 		/* phy resume failed */
214 		ata_link_printk(link, KERN_WARNING, "failed to resume link "
215 				"for reset (errno=%d)\n", rc);
216 		return rc;
217 	}
218 
219 	/* clear SError bits including .X which blocks the port when set */
220 	rc = sata_scr_write(link, SCR_ERROR, 0xffffffff);
221 	if (rc) {
222 		ata_link_printk(link, KERN_ERR,
223 				"failed to clear SError (errno=%d)\n", rc);
224 		return rc;
225 	}
226 
227 	return 0;
228 }
229 
230 /**
231  *	sata_pmp_std_hardreset - standard hardreset method for PMP link
232  *	@link: link to be reset
233  *	@class: resulting class of attached device
234  *	@deadline: deadline jiffies for the operation
235  *
236  *	Hardreset PMP port @link.  Note that this function doesn't
237  *	wait for BSY clearance.  There simply isn't a generic way to
238  *	wait the event.  Instead, this function return -EAGAIN thus
239  *	telling libata-EH to followup with softreset.
240  *
241  *	LOCKING:
242  *	Kernel thread context (may sleep)
243  *
244  *	RETURNS:
245  *	0 on success, -errno otherwise.
246  */
247 int sata_pmp_std_hardreset(struct ata_link *link, unsigned int *class,
248 			   unsigned long deadline)
249 {
250 	const unsigned long *timing = sata_ehc_deb_timing(&link->eh_context);
251 	u32 tmp;
252 	int rc;
253 
254 	DPRINTK("ENTER\n");
255 
256 	/* do hardreset */
257 	rc = sata_link_hardreset(link, timing, deadline);
258 	if (rc) {
259 		ata_link_printk(link, KERN_ERR,
260 				"COMRESET failed (errno=%d)\n", rc);
261 		goto out;
262 	}
263 
264 	/* clear SError bits including .X which blocks the port when set */
265 	rc = sata_scr_write(link, SCR_ERROR, 0xffffffff);
266 	if (rc) {
267 		ata_link_printk(link, KERN_ERR, "failed to clear SError "
268 				"during hardreset (errno=%d)\n", rc);
269 		goto out;
270 	}
271 
272 	/* if device is present, follow up with srst to wait for !BSY */
273 	if (ata_link_online(link))
274 		rc = -EAGAIN;
275  out:
276 	/* if SCR isn't accessible, we need to reset the PMP */
277 	if (rc && rc != -EAGAIN && sata_scr_read(link, SCR_STATUS, &tmp))
278 		rc = -ERESTART;
279 
280 	DPRINTK("EXIT, rc=%d\n", rc);
281 	return rc;
282 }
283 
284 /**
285  *	ata_std_postreset - standard postreset method for PMP link
286  *	@link: the target ata_link
287  *	@classes: classes of attached devices
288  *
289  *	This function is invoked after a successful reset.  Note that
290  *	the device might have been reset more than once using
291  *	different reset methods before postreset is invoked.
292  *
293  *	LOCKING:
294  *	Kernel thread context (may sleep)
295  */
296 void sata_pmp_std_postreset(struct ata_link *link, unsigned int *class)
297 {
298 	u32 serror;
299 
300 	DPRINTK("ENTER\n");
301 
302 	/* clear SError */
303 	if (sata_scr_read(link, SCR_ERROR, &serror) == 0)
304 		sata_scr_write(link, SCR_ERROR, serror);
305 
306 	/* print link status */
307 	sata_print_link_status(link);
308 
309 	DPRINTK("EXIT\n");
310 }
311 
312 /**
313  *	sata_pmp_read_gscr - read GSCR block of SATA PMP
314  *	@dev: PMP device
315  *	@gscr: buffer to read GSCR block into
316  *
317  *	Read selected PMP GSCRs from the PMP at @dev.  This will serve
318  *	as configuration and identification info for the PMP.
319  *
320  *	LOCKING:
321  *	Kernel thread context (may sleep).
322  *
323  *	RETURNS:
324  *	0 on success, -errno on failure.
325  */
326 static int sata_pmp_read_gscr(struct ata_device *dev, u32 *gscr)
327 {
328 	static const int gscr_to_read[] = { 0, 1, 2, 32, 33, 64, 96 };
329 	int i;
330 
331 	for (i = 0; i < ARRAY_SIZE(gscr_to_read); i++) {
332 		int reg = gscr_to_read[i];
333 		unsigned int err_mask;
334 
335 		err_mask = sata_pmp_read(dev->link, reg, &gscr[reg]);
336 		if (err_mask) {
337 			ata_dev_printk(dev, KERN_ERR, "failed to read PMP "
338 				"GSCR[%d] (Emask=0x%x)\n", reg, err_mask);
339 			return -EIO;
340 		}
341 	}
342 
343 	return 0;
344 }
345 
346 static const char *sata_pmp_spec_rev_str(const u32 *gscr)
347 {
348 	u32 rev = gscr[SATA_PMP_GSCR_REV];
349 
350 	if (rev & (1 << 2))
351 		return "1.1";
352 	if (rev & (1 << 1))
353 		return "1.0";
354 	return "<unknown>";
355 }
356 
357 static int sata_pmp_configure(struct ata_device *dev, int print_info)
358 {
359 	struct ata_port *ap = dev->link->ap;
360 	u32 *gscr = dev->gscr;
361 	unsigned int err_mask = 0;
362 	const char *reason;
363 	int nr_ports, rc;
364 
365 	nr_ports = sata_pmp_gscr_ports(gscr);
366 
367 	if (nr_ports <= 0 || nr_ports > SATA_PMP_MAX_PORTS) {
368 		rc = -EINVAL;
369 		reason = "invalid nr_ports";
370 		goto fail;
371 	}
372 
373 	if ((ap->flags & ATA_FLAG_AN) &&
374 	    (gscr[SATA_PMP_GSCR_FEAT] & SATA_PMP_FEAT_NOTIFY))
375 		dev->flags |= ATA_DFLAG_AN;
376 
377 	/* monitor SERR_PHYRDY_CHG on fan-out ports */
378 	err_mask = sata_pmp_write(dev->link, SATA_PMP_GSCR_ERROR_EN,
379 				  SERR_PHYRDY_CHG);
380 	if (err_mask) {
381 		rc = -EIO;
382 		reason = "failed to write GSCR_ERROR_EN";
383 		goto fail;
384 	}
385 
386 	/* turn off notification till fan-out ports are reset and configured */
387 	if (gscr[SATA_PMP_GSCR_FEAT_EN] & SATA_PMP_FEAT_NOTIFY) {
388 		gscr[SATA_PMP_GSCR_FEAT_EN] &= ~SATA_PMP_FEAT_NOTIFY;
389 
390 		err_mask = sata_pmp_write(dev->link, SATA_PMP_GSCR_FEAT_EN,
391 					  gscr[SATA_PMP_GSCR_FEAT_EN]);
392 		if (err_mask) {
393 			rc = -EIO;
394 			reason = "failed to write GSCR_FEAT_EN";
395 			goto fail;
396 		}
397 	}
398 
399 	if (print_info) {
400 		ata_dev_printk(dev, KERN_INFO, "Port Multiplier %s, "
401 			       "0x%04x:0x%04x r%d, %d ports, feat 0x%x/0x%x\n",
402 			       sata_pmp_spec_rev_str(gscr),
403 			       sata_pmp_gscr_vendor(gscr),
404 			       sata_pmp_gscr_devid(gscr),
405 			       sata_pmp_gscr_rev(gscr),
406 			       nr_ports, gscr[SATA_PMP_GSCR_FEAT_EN],
407 			       gscr[SATA_PMP_GSCR_FEAT]);
408 
409 		if (!(dev->flags & ATA_DFLAG_AN))
410 			ata_dev_printk(dev, KERN_INFO,
411 				"Asynchronous notification not supported, "
412 				"hotplug won't\n         work on fan-out "
413 				"ports. Use warm-plug instead.\n");
414 	}
415 
416 	return 0;
417 
418  fail:
419 	ata_dev_printk(dev, KERN_ERR,
420 		       "failed to configure Port Multiplier (%s, Emask=0x%x)\n",
421 		       reason, err_mask);
422 	return rc;
423 }
424 
425 static int sata_pmp_init_links(struct ata_port *ap, int nr_ports)
426 {
427 	struct ata_link *pmp_link = ap->pmp_link;
428 	int i;
429 
430 	if (!pmp_link) {
431 		pmp_link = kzalloc(sizeof(pmp_link[0]) * SATA_PMP_MAX_PORTS,
432 				   GFP_NOIO);
433 		if (!pmp_link)
434 			return -ENOMEM;
435 
436 		for (i = 0; i < SATA_PMP_MAX_PORTS; i++)
437 			ata_link_init(ap, &pmp_link[i], i);
438 
439 		ap->pmp_link = pmp_link;
440 	}
441 
442 	for (i = 0; i < nr_ports; i++) {
443 		struct ata_link *link = &pmp_link[i];
444 		struct ata_eh_context *ehc = &link->eh_context;
445 
446 		link->flags = 0;
447 		ehc->i.probe_mask |= 1;
448 		ehc->i.action |= ATA_EH_SOFTRESET;
449 		ehc->i.flags |= ATA_EHI_RESUME_LINK;
450 	}
451 
452 	return 0;
453 }
454 
455 static void sata_pmp_quirks(struct ata_port *ap)
456 {
457 	u32 *gscr = ap->link.device->gscr;
458 	u16 vendor = sata_pmp_gscr_vendor(gscr);
459 	u16 devid = sata_pmp_gscr_devid(gscr);
460 	struct ata_link *link;
461 
462 	if (vendor == 0x1095 && devid == 0x3726) {
463 		/* sil3726 quirks */
464 		ata_port_for_each_link(link, ap) {
465 			/* SError.N need a kick in the ass to get working */
466 			link->flags |= ATA_LFLAG_HRST_TO_RESUME;
467 
468 			/* class code report is unreliable */
469 			if (link->pmp < 5)
470 				link->flags |= ATA_LFLAG_ASSUME_ATA;
471 
472 			/* port 5 is for SEMB device and it doesn't like SRST */
473 			if (link->pmp == 5)
474 				link->flags |= ATA_LFLAG_NO_SRST |
475 					       ATA_LFLAG_ASSUME_SEMB;
476 		}
477 	} else if (vendor == 0x1095 && devid == 0x4723) {
478 		/* sil4723 quirks */
479 		ata_port_for_each_link(link, ap) {
480 			/* SError.N need a kick in the ass to get working */
481 			link->flags |= ATA_LFLAG_HRST_TO_RESUME;
482 
483 			/* class code report is unreliable */
484 			if (link->pmp < 2)
485 				link->flags |= ATA_LFLAG_ASSUME_ATA;
486 
487 			/* the config device at port 2 locks up on SRST */
488 			if (link->pmp == 2)
489 				link->flags |= ATA_LFLAG_NO_SRST |
490 					       ATA_LFLAG_ASSUME_ATA;
491 		}
492 	} else if (vendor == 0x1095 && devid == 0x4726) {
493 		/* sil4726 quirks */
494 		ata_port_for_each_link(link, ap) {
495 			/* SError.N need a kick in the ass to get working */
496 			link->flags |= ATA_LFLAG_HRST_TO_RESUME;
497 
498 			/* Class code report is unreliable and SRST
499 			 * times out under certain configurations.
500 			 * Config device can be at port 0 or 5 and
501 			 * locks up on SRST.
502 			 */
503 			if (link->pmp <= 5)
504 				link->flags |= ATA_LFLAG_NO_SRST |
505 					       ATA_LFLAG_ASSUME_ATA;
506 
507 			/* Port 6 is for SEMB device which doesn't
508 			 * like SRST either.
509 			 */
510 			if (link->pmp == 6)
511 				link->flags |= ATA_LFLAG_NO_SRST |
512 					       ATA_LFLAG_ASSUME_SEMB;
513 		}
514 	} else if (vendor == 0x1095 && (devid == 0x5723 || devid == 0x5733 ||
515 					devid == 0x5734 || devid == 0x5744)) {
516 		/* sil5723/5744 quirks */
517 
518 		/* sil5723/5744 has either two or three downstream
519 		 * ports depending on operation mode.  The last port
520 		 * is empty if any actual IO device is available or
521 		 * occupied by a pseudo configuration device
522 		 * otherwise.  Don't try hard to recover it.
523 		 */
524 		ap->pmp_link[ap->nr_pmp_links - 1].flags |= ATA_LFLAG_NO_RETRY;
525 	} else if (vendor == 0x11ab && devid == 0x4140) {
526 		/* Marvell 88SM4140 quirks.  Fan-out ports require PHY
527 		 * reset to work; other than that, it behaves very
528 		 * nicely.
529 		 */
530 		ata_port_for_each_link(link, ap)
531 			link->flags |= ATA_LFLAG_HRST_TO_RESUME;
532 	}
533 }
534 
535 /**
536  *	sata_pmp_attach - attach a SATA PMP device
537  *	@dev: SATA PMP device to attach
538  *
539  *	Configure and attach SATA PMP device @dev.  This function is
540  *	also responsible for allocating and initializing PMP links.
541  *
542  *	LOCKING:
543  *	Kernel thread context (may sleep).
544  *
545  *	RETURNS:
546  *	0 on success, -errno on failure.
547  */
548 int sata_pmp_attach(struct ata_device *dev)
549 {
550 	struct ata_link *link = dev->link;
551 	struct ata_port *ap = link->ap;
552 	unsigned long flags;
553 	struct ata_link *tlink;
554 	int rc;
555 
556 	/* is it hanging off the right place? */
557 	if (!(ap->flags & ATA_FLAG_PMP)) {
558 		ata_dev_printk(dev, KERN_ERR,
559 			       "host does not support Port Multiplier\n");
560 		return -EINVAL;
561 	}
562 
563 	if (!ata_is_host_link(link)) {
564 		ata_dev_printk(dev, KERN_ERR,
565 			       "Port Multipliers cannot be nested\n");
566 		return -EINVAL;
567 	}
568 
569 	if (dev->devno) {
570 		ata_dev_printk(dev, KERN_ERR,
571 			       "Port Multiplier must be the first device\n");
572 		return -EINVAL;
573 	}
574 
575 	WARN_ON(link->pmp != 0);
576 	link->pmp = SATA_PMP_CTRL_PORT;
577 
578 	/* read GSCR block */
579 	rc = sata_pmp_read_gscr(dev, dev->gscr);
580 	if (rc)
581 		goto fail;
582 
583 	/* config PMP */
584 	rc = sata_pmp_configure(dev, 1);
585 	if (rc)
586 		goto fail;
587 
588 	rc = sata_pmp_init_links(ap, sata_pmp_gscr_ports(dev->gscr));
589 	if (rc) {
590 		ata_dev_printk(dev, KERN_INFO,
591 			       "failed to initialize PMP links\n");
592 		goto fail;
593 	}
594 
595 	/* attach it */
596 	spin_lock_irqsave(ap->lock, flags);
597 	WARN_ON(ap->nr_pmp_links);
598 	ap->nr_pmp_links = sata_pmp_gscr_ports(dev->gscr);
599 	spin_unlock_irqrestore(ap->lock, flags);
600 
601 	sata_pmp_quirks(ap);
602 
603 	if (ap->ops->pmp_attach)
604 		ap->ops->pmp_attach(ap);
605 
606 	ata_port_for_each_link(tlink, ap)
607 		sata_link_init_spd(tlink);
608 
609 	ata_acpi_associate_sata_port(ap);
610 
611 	return 0;
612 
613  fail:
614 	link->pmp = 0;
615 	return rc;
616 }
617 
618 /**
619  *	sata_pmp_detach - detach a SATA PMP device
620  *	@dev: SATA PMP device to detach
621  *
622  *	Detach SATA PMP device @dev.  This function is also
623  *	responsible for deconfiguring PMP links.
624  *
625  *	LOCKING:
626  *	Kernel thread context (may sleep).
627  */
628 static void sata_pmp_detach(struct ata_device *dev)
629 {
630 	struct ata_link *link = dev->link;
631 	struct ata_port *ap = link->ap;
632 	struct ata_link *tlink;
633 	unsigned long flags;
634 
635 	ata_dev_printk(dev, KERN_INFO, "Port Multiplier detaching\n");
636 
637 	WARN_ON(!ata_is_host_link(link) || dev->devno ||
638 		link->pmp != SATA_PMP_CTRL_PORT);
639 
640 	if (ap->ops->pmp_detach)
641 		ap->ops->pmp_detach(ap);
642 
643 	ata_port_for_each_link(tlink, ap)
644 		ata_eh_detach_dev(tlink->device);
645 
646 	spin_lock_irqsave(ap->lock, flags);
647 	ap->nr_pmp_links = 0;
648 	link->pmp = 0;
649 	spin_unlock_irqrestore(ap->lock, flags);
650 
651 	ata_acpi_associate_sata_port(ap);
652 }
653 
654 /**
655  *	sata_pmp_same_pmp - does new GSCR matches the configured PMP?
656  *	@dev: PMP device to compare against
657  *	@new_gscr: GSCR block of the new device
658  *
659  *	Compare @new_gscr against @dev and determine whether @dev is
660  *	the PMP described by @new_gscr.
661  *
662  *	LOCKING:
663  *	None.
664  *
665  *	RETURNS:
666  *	1 if @dev matches @new_gscr, 0 otherwise.
667  */
668 static int sata_pmp_same_pmp(struct ata_device *dev, const u32 *new_gscr)
669 {
670 	const u32 *old_gscr = dev->gscr;
671 	u16 old_vendor, new_vendor, old_devid, new_devid;
672 	int old_nr_ports, new_nr_ports;
673 
674 	old_vendor = sata_pmp_gscr_vendor(old_gscr);
675 	new_vendor = sata_pmp_gscr_vendor(new_gscr);
676 	old_devid = sata_pmp_gscr_devid(old_gscr);
677 	new_devid = sata_pmp_gscr_devid(new_gscr);
678 	old_nr_ports = sata_pmp_gscr_ports(old_gscr);
679 	new_nr_ports = sata_pmp_gscr_ports(new_gscr);
680 
681 	if (old_vendor != new_vendor) {
682 		ata_dev_printk(dev, KERN_INFO, "Port Multiplier "
683 			       "vendor mismatch '0x%x' != '0x%x'\n",
684 			       old_vendor, new_vendor);
685 		return 0;
686 	}
687 
688 	if (old_devid != new_devid) {
689 		ata_dev_printk(dev, KERN_INFO, "Port Multiplier "
690 			       "device ID mismatch '0x%x' != '0x%x'\n",
691 			       old_devid, new_devid);
692 		return 0;
693 	}
694 
695 	if (old_nr_ports != new_nr_ports) {
696 		ata_dev_printk(dev, KERN_INFO, "Port Multiplier "
697 			       "nr_ports mismatch '0x%x' != '0x%x'\n",
698 			       old_nr_ports, new_nr_ports);
699 		return 0;
700 	}
701 
702 	return 1;
703 }
704 
705 /**
706  *	sata_pmp_revalidate - revalidate SATA PMP
707  *	@dev: PMP device to revalidate
708  *	@new_class: new class code
709  *
710  *	Re-read GSCR block and make sure @dev is still attached to the
711  *	port and properly configured.
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(struct ata_device *dev, unsigned int new_class)
720 {
721 	struct ata_link *link = dev->link;
722 	struct ata_port *ap = link->ap;
723 	u32 *gscr = (void *)ap->sector_buf;
724 	int rc;
725 
726 	DPRINTK("ENTER\n");
727 
728 	ata_eh_about_to_do(link, NULL, ATA_EH_REVALIDATE);
729 
730 	if (!ata_dev_enabled(dev)) {
731 		rc = -ENODEV;
732 		goto fail;
733 	}
734 
735 	/* wrong class? */
736 	if (ata_class_enabled(new_class) && new_class != ATA_DEV_PMP) {
737 		rc = -ENODEV;
738 		goto fail;
739 	}
740 
741 	/* read GSCR */
742 	rc = sata_pmp_read_gscr(dev, gscr);
743 	if (rc)
744 		goto fail;
745 
746 	/* is the pmp still there? */
747 	if (!sata_pmp_same_pmp(dev, gscr)) {
748 		rc = -ENODEV;
749 		goto fail;
750 	}
751 
752 	memcpy(dev->gscr, gscr, sizeof(gscr[0]) * SATA_PMP_GSCR_DWORDS);
753 
754 	rc = sata_pmp_configure(dev, 0);
755 	if (rc)
756 		goto fail;
757 
758 	ata_eh_done(link, NULL, ATA_EH_REVALIDATE);
759 
760 	DPRINTK("EXIT, rc=0\n");
761 	return 0;
762 
763  fail:
764 	ata_dev_printk(dev, KERN_ERR,
765 		       "PMP revalidation failed (errno=%d)\n", rc);
766 	DPRINTK("EXIT, rc=%d\n", rc);
767 	return rc;
768 }
769 
770 /**
771  *	sata_pmp_revalidate_quick - revalidate SATA PMP quickly
772  *	@dev: PMP device to revalidate
773  *
774  *	Make sure the attached PMP is accessible.
775  *
776  *	LOCKING:
777  *	Kernel thread context (may sleep).
778  *
779  *	RETURNS:
780  *	0 on success, -errno otherwise.
781  */
782 static int sata_pmp_revalidate_quick(struct ata_device *dev)
783 {
784 	unsigned int err_mask;
785 	u32 prod_id;
786 
787 	err_mask = sata_pmp_read(dev->link, SATA_PMP_GSCR_PROD_ID, &prod_id);
788 	if (err_mask) {
789 		ata_dev_printk(dev, KERN_ERR, "failed to read PMP product ID "
790 			       "(Emask=0x%x)\n", err_mask);
791 		return -EIO;
792 	}
793 
794 	if (prod_id != dev->gscr[SATA_PMP_GSCR_PROD_ID]) {
795 		ata_dev_printk(dev, KERN_ERR, "PMP product ID mismatch\n");
796 		/* something weird is going on, request full PMP recovery */
797 		return -EIO;
798 	}
799 
800 	return 0;
801 }
802 
803 /**
804  *	sata_pmp_eh_recover_pmp - recover PMP
805  *	@ap: ATA port PMP is attached to
806  *	@prereset: prereset method (can be NULL)
807  *	@softreset: softreset method
808  *	@hardreset: hardreset method
809  *	@postreset: postreset method (can be NULL)
810  *
811  *	Recover PMP attached to @ap.  Recovery procedure is somewhat
812  *	similar to that of ata_eh_recover() except that reset should
813  *	always be performed in hard->soft sequence and recovery
814  *	failure results in PMP detachment.
815  *
816  *	LOCKING:
817  *	Kernel thread context (may sleep).
818  *
819  *	RETURNS:
820  *	0 on success, -errno on failure.
821  */
822 static int sata_pmp_eh_recover_pmp(struct ata_port *ap,
823 		ata_prereset_fn_t prereset, ata_reset_fn_t softreset,
824 		ata_reset_fn_t hardreset, ata_postreset_fn_t postreset)
825 {
826 	struct ata_link *link = &ap->link;
827 	struct ata_eh_context *ehc = &link->eh_context;
828 	struct ata_device *dev = link->device;
829 	int tries = ATA_EH_PMP_TRIES;
830 	int detach = 0, rc = 0;
831 	int reval_failed = 0;
832 
833 	DPRINTK("ENTER\n");
834 
835 	if (dev->flags & ATA_DFLAG_DETACH) {
836 		detach = 1;
837 		goto fail;
838 	}
839 
840  retry:
841 	ehc->classes[0] = ATA_DEV_UNKNOWN;
842 
843 	if (ehc->i.action & ATA_EH_RESET_MASK) {
844 		struct ata_link *tlink;
845 
846 		ata_eh_freeze_port(ap);
847 
848 		/* reset */
849 		ehc->i.action = ATA_EH_HARDRESET;
850 		rc = ata_eh_reset(link, 0, prereset, softreset, hardreset,
851 				  postreset);
852 		if (rc) {
853 			ata_link_printk(link, KERN_ERR,
854 					"failed to reset PMP, giving up\n");
855 			goto fail;
856 		}
857 
858 		ata_eh_thaw_port(ap);
859 
860 		/* PMP is reset, SErrors cannot be trusted, scan all */
861 		ata_port_for_each_link(tlink, ap)
862 			ata_ehi_schedule_probe(&tlink->eh_context.i);
863 	}
864 
865 	/* If revalidation is requested, revalidate and reconfigure;
866 	 * otherwise, do quick revalidation.
867 	 */
868 	if (ehc->i.action & ATA_EH_REVALIDATE)
869 		rc = sata_pmp_revalidate(dev, ehc->classes[0]);
870 	else
871 		rc = sata_pmp_revalidate_quick(dev);
872 
873 	if (rc) {
874 		tries--;
875 
876 		if (rc == -ENODEV) {
877 			ehc->i.probe_mask |= 1;
878 			detach = 1;
879 			/* give it just two more chances */
880 			tries = min(tries, 2);
881 		}
882 
883 		if (tries) {
884 			int sleep = ehc->i.flags & ATA_EHI_DID_RESET;
885 
886 			/* consecutive revalidation failures? speed down */
887 			if (reval_failed)
888 				sata_down_spd_limit(link);
889 			else
890 				reval_failed = 1;
891 
892 			ata_dev_printk(dev, KERN_WARNING,
893 				       "retrying hardreset%s\n",
894 				       sleep ? " in 5 secs" : "");
895 			if (sleep)
896 				ssleep(5);
897 			ehc->i.action |= ATA_EH_HARDRESET;
898 			goto retry;
899 		} else {
900 			ata_dev_printk(dev, KERN_ERR, "failed to recover PMP "
901 				       "after %d tries, giving up\n",
902 				       ATA_EH_PMP_TRIES);
903 			goto fail;
904 		}
905 	}
906 
907 	/* okay, PMP resurrected */
908 	ehc->i.flags = 0;
909 
910 	DPRINTK("EXIT, rc=0\n");
911 	return 0;
912 
913  fail:
914 	sata_pmp_detach(dev);
915 	if (detach)
916 		ata_eh_detach_dev(dev);
917 	else
918 		ata_dev_disable(dev);
919 
920 	DPRINTK("EXIT, rc=%d\n", rc);
921 	return rc;
922 }
923 
924 static int sata_pmp_eh_handle_disabled_links(struct ata_port *ap)
925 {
926 	struct ata_link *link;
927 	unsigned long flags;
928 	int rc;
929 
930 	spin_lock_irqsave(ap->lock, flags);
931 
932 	ata_port_for_each_link(link, ap) {
933 		if (!(link->flags & ATA_LFLAG_DISABLED))
934 			continue;
935 
936 		spin_unlock_irqrestore(ap->lock, flags);
937 
938 		/* Some PMPs require hardreset sequence to get
939 		 * SError.N working.
940 		 */
941 		if ((link->flags & ATA_LFLAG_HRST_TO_RESUME) &&
942 		    (link->eh_context.i.flags & ATA_EHI_RESUME_LINK))
943 			sata_link_hardreset(link, sata_deb_timing_normal,
944 					    jiffies + ATA_TMOUT_INTERNAL_QUICK);
945 
946 		/* unconditionally clear SError.N */
947 		rc = sata_scr_write(link, SCR_ERROR, SERR_PHYRDY_CHG);
948 		if (rc) {
949 			ata_link_printk(link, KERN_ERR, "failed to clear "
950 					"SError.N (errno=%d)\n", rc);
951 			return rc;
952 		}
953 
954 		spin_lock_irqsave(ap->lock, flags);
955 	}
956 
957 	spin_unlock_irqrestore(ap->lock, flags);
958 
959 	return 0;
960 }
961 
962 static int sata_pmp_handle_link_fail(struct ata_link *link, int *link_tries)
963 {
964 	struct ata_port *ap = link->ap;
965 	unsigned long flags;
966 
967 	if (link_tries[link->pmp] && --link_tries[link->pmp])
968 		return 1;
969 
970 	/* disable this link */
971 	if (!(link->flags & ATA_LFLAG_DISABLED)) {
972 		ata_link_printk(link, KERN_WARNING,
973 			"failed to recover link after %d tries, disabling\n",
974 			ATA_EH_PMP_LINK_TRIES);
975 
976 		spin_lock_irqsave(ap->lock, flags);
977 		link->flags |= ATA_LFLAG_DISABLED;
978 		spin_unlock_irqrestore(ap->lock, flags);
979 	}
980 
981 	ata_dev_disable(link->device);
982 	link->eh_context.i.action = 0;
983 
984 	return 0;
985 }
986 
987 /**
988  *	sata_pmp_eh_recover - recover PMP-enabled port
989  *	@ap: ATA port to recover
990  *	@prereset: prereset method (can be NULL)
991  *	@softreset: softreset method
992  *	@hardreset: hardreset method
993  *	@postreset: postreset method (can be NULL)
994  *	@pmp_prereset: PMP prereset method (can be NULL)
995  *	@pmp_softreset: PMP softreset method (can be NULL)
996  *	@pmp_hardreset: PMP hardreset method (can be NULL)
997  *	@pmp_postreset: PMP postreset method (can be NULL)
998  *
999  *	Drive EH recovery operation for PMP enabled port @ap.  This
1000  *	function recovers host and PMP ports with proper retrials and
1001  *	fallbacks.  Actual recovery operations are performed using
1002  *	ata_eh_recover() and sata_pmp_eh_recover_pmp().
1003  *
1004  *	LOCKING:
1005  *	Kernel thread context (may sleep).
1006  *
1007  *	RETURNS:
1008  *	0 on success, -errno on failure.
1009  */
1010 static int sata_pmp_eh_recover(struct ata_port *ap,
1011 		ata_prereset_fn_t prereset, ata_reset_fn_t softreset,
1012 		ata_reset_fn_t hardreset, ata_postreset_fn_t postreset,
1013 		ata_prereset_fn_t pmp_prereset, ata_reset_fn_t pmp_softreset,
1014 		ata_reset_fn_t pmp_hardreset, ata_postreset_fn_t pmp_postreset)
1015 {
1016 	int pmp_tries, link_tries[SATA_PMP_MAX_PORTS];
1017 	struct ata_link *pmp_link = &ap->link;
1018 	struct ata_device *pmp_dev = pmp_link->device;
1019 	struct ata_eh_context *pmp_ehc = &pmp_link->eh_context;
1020 	struct ata_link *link;
1021 	struct ata_device *dev;
1022 	unsigned int err_mask;
1023 	u32 gscr_error, sntf;
1024 	int cnt, rc;
1025 
1026 	pmp_tries = ATA_EH_PMP_TRIES;
1027 	ata_port_for_each_link(link, ap)
1028 		link_tries[link->pmp] = ATA_EH_PMP_LINK_TRIES;
1029 
1030  retry:
1031 	/* PMP attached? */
1032 	if (!ap->nr_pmp_links) {
1033 		rc = ata_eh_recover(ap, prereset, softreset, hardreset,
1034 				    postreset, NULL);
1035 		if (rc) {
1036 			ata_link_for_each_dev(dev, &ap->link)
1037 				ata_dev_disable(dev);
1038 			return rc;
1039 		}
1040 
1041 		if (pmp_dev->class != ATA_DEV_PMP)
1042 			return 0;
1043 
1044 		/* new PMP online */
1045 		ata_port_for_each_link(link, ap)
1046 			link_tries[link->pmp] = ATA_EH_PMP_LINK_TRIES;
1047 
1048 		/* fall through */
1049 	}
1050 
1051 	/* recover pmp */
1052 	rc = sata_pmp_eh_recover_pmp(ap, prereset, softreset, hardreset,
1053 				     postreset);
1054 	if (rc)
1055 		goto pmp_fail;
1056 
1057 	/* handle disabled links */
1058 	rc = sata_pmp_eh_handle_disabled_links(ap);
1059 	if (rc)
1060 		goto pmp_fail;
1061 
1062 	/* recover links */
1063 	rc = ata_eh_recover(ap, pmp_prereset, pmp_softreset, pmp_hardreset,
1064 			    pmp_postreset, &link);
1065 	if (rc)
1066 		goto link_fail;
1067 
1068 	/* Connection status might have changed while resetting other
1069 	 * links, check SATA_PMP_GSCR_ERROR before returning.
1070 	 */
1071 
1072 	/* clear SNotification */
1073 	rc = sata_scr_read(&ap->link, SCR_NOTIFICATION, &sntf);
1074 	if (rc == 0)
1075 		sata_scr_write(&ap->link, SCR_NOTIFICATION, sntf);
1076 
1077 	/* enable notification */
1078 	if (pmp_dev->flags & ATA_DFLAG_AN) {
1079 		pmp_dev->gscr[SATA_PMP_GSCR_FEAT_EN] |= SATA_PMP_FEAT_NOTIFY;
1080 
1081 		err_mask = sata_pmp_write(pmp_dev->link, SATA_PMP_GSCR_FEAT_EN,
1082 					  pmp_dev->gscr[SATA_PMP_GSCR_FEAT_EN]);
1083 		if (err_mask) {
1084 			ata_dev_printk(pmp_dev, KERN_ERR, "failed to write "
1085 				       "PMP_FEAT_EN (Emask=0x%x)\n", err_mask);
1086 			rc = -EIO;
1087 			goto pmp_fail;
1088 		}
1089 	}
1090 
1091 	/* check GSCR_ERROR */
1092 	err_mask = sata_pmp_read(pmp_link, SATA_PMP_GSCR_ERROR, &gscr_error);
1093 	if (err_mask) {
1094 		ata_dev_printk(pmp_dev, KERN_ERR, "failed to read "
1095 			       "PMP_GSCR_ERROR (Emask=0x%x)\n", err_mask);
1096 		rc = -EIO;
1097 		goto pmp_fail;
1098 	}
1099 
1100 	cnt = 0;
1101 	ata_port_for_each_link(link, ap) {
1102 		if (!(gscr_error & (1 << link->pmp)))
1103 			continue;
1104 
1105 		if (sata_pmp_handle_link_fail(link, link_tries)) {
1106 			ata_ehi_hotplugged(&link->eh_context.i);
1107 			cnt++;
1108 		} else {
1109 			ata_link_printk(link, KERN_WARNING,
1110 				"PHY status changed but maxed out on retries, "
1111 				"giving up\n");
1112 			ata_link_printk(link, KERN_WARNING,
1113 				"Manully issue scan to resume this link\n");
1114 		}
1115 	}
1116 
1117 	if (cnt) {
1118 		ata_port_printk(ap, KERN_INFO, "PMP SError.N set for some "
1119 				"ports, repeating recovery\n");
1120 		goto retry;
1121 	}
1122 
1123 	return 0;
1124 
1125  link_fail:
1126 	if (sata_pmp_handle_link_fail(link, link_tries)) {
1127 		pmp_ehc->i.action |= ATA_EH_HARDRESET;
1128 		goto retry;
1129 	}
1130 
1131 	/* fall through */
1132  pmp_fail:
1133 	/* Control always ends up here after detaching PMP.  Shut up
1134 	 * and return if we're unloading.
1135 	 */
1136 	if (ap->pflags & ATA_PFLAG_UNLOADING)
1137 		return rc;
1138 
1139 	if (!ap->nr_pmp_links)
1140 		goto retry;
1141 
1142 	if (--pmp_tries) {
1143 		ata_port_printk(ap, KERN_WARNING,
1144 				"failed to recover PMP, retrying in 5 secs\n");
1145 		pmp_ehc->i.action |= ATA_EH_HARDRESET;
1146 		ssleep(5);
1147 		goto retry;
1148 	}
1149 
1150 	ata_port_printk(ap, KERN_ERR,
1151 			"failed to recover PMP after %d tries, giving up\n",
1152 			ATA_EH_PMP_TRIES);
1153 	sata_pmp_detach(pmp_dev);
1154 	ata_dev_disable(pmp_dev);
1155 
1156 	return rc;
1157 }
1158 
1159 /**
1160  *	sata_pmp_do_eh - do standard error handling for PMP-enabled host
1161  *	@ap: host port to handle error for
1162  *	@prereset: prereset method (can be NULL)
1163  *	@softreset: softreset method
1164  *	@hardreset: hardreset method
1165  *	@postreset: postreset method (can be NULL)
1166  *	@pmp_prereset: PMP prereset method (can be NULL)
1167  *	@pmp_softreset: PMP softreset method (can be NULL)
1168  *	@pmp_hardreset: PMP hardreset method (can be NULL)
1169  *	@pmp_postreset: PMP postreset method (can be NULL)
1170  *
1171  *	Perform standard error handling sequence for PMP-enabled host
1172  *	@ap.
1173  *
1174  *	LOCKING:
1175  *	Kernel thread context (may sleep).
1176  */
1177 void sata_pmp_do_eh(struct ata_port *ap,
1178 		ata_prereset_fn_t prereset, ata_reset_fn_t softreset,
1179 		ata_reset_fn_t hardreset, ata_postreset_fn_t postreset,
1180 		ata_prereset_fn_t pmp_prereset, ata_reset_fn_t pmp_softreset,
1181 		ata_reset_fn_t pmp_hardreset, ata_postreset_fn_t pmp_postreset)
1182 {
1183 	ata_eh_autopsy(ap);
1184 	ata_eh_report(ap);
1185 	sata_pmp_eh_recover(ap, prereset, softreset, hardreset, postreset,
1186 			    pmp_prereset, pmp_softreset, pmp_hardreset,
1187 			    pmp_postreset);
1188 	ata_eh_finish(ap);
1189 }
1190