Re: PM works with SiI3124 + SiI3726

[kadowaki@bunkai.com]

[-- Attachment #1: Type: text/plain, Size: 4203 bytes --]

Hi,


I found there are one extra port detected in Sil3726, where Sil4726 
reports two extra ports.

Attached is libata-pm.c which works fine in my box.


$ dmesg|grep -A 86 libata
libata version 1.30 loaded.
sata_sil24 0000:03:03.0: version 0.24
ACPI: PCI Interrupt 0000:03:03.0[A] -> GSI 56 (level, low) -> IRQ 177
sata_sil24 0000:03:03.0: Applying completion IRQ loss on PCI-X errata 
fix
ata1: SATA max UDMA/100 cmd 0xF8D90000 ctl 0x0 bmdma 0x0 irq 177
ata2: SATA max UDMA/100 cmd 0xF8D92000 ctl 0x0 bmdma 0x0 irq 177
ata3: SATA max UDMA/100 cmd 0xF8D94000 ctl 0x0 bmdma 0x0 irq 177
ata4: SATA max UDMA/100 cmd 0xF8D96000 ctl 0x0 bmdma 0x0 irq 177
scsi0 : sata_sil24
ata1: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
ata1.15: Port Multiplier 1.1, 0x1095:0x3726 r23, 5 ports, feat 0x9/0x9
ata1.00: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
ata1.01: SATA link down (SStatus 0 SControl 300)
ata1.02: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
ata1.03: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
ata1.04: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
ata1.00: cfg 49:2f00 82:346b 83:7f21 84:4003 85:3469 86:3c01 87:4003 88:
007f
ata1.00: ATA-6, max UDMA/133, 72303840 sectors: LBA48
ata1.00: applying bridge limits
ata1.00: configured for UDMA/100
ata1.02: cfg 49:2f00 82:346b 83:7d01 84:5823 85:3469 86:3c01 87:4023 88:
207f
ata1.02: ATA-7, max UDMA/133, 488397168 sectors: LBA48 NCQ (depth 31/32)
ata1.02: configured for UDMA/100
ata1.03: cfg 49:2f00 82:346b 83:7d01 84:5823 85:3469 86:3c01 87:4023 88:
207f
ata1.03: ATA-7, max UDMA/133, 488397168 sectors: LBA48 NCQ (depth 31/32)
ata1.03: configured for UDMA/100
ata1.04: cfg 49:2f00 82:7c6b 83:7f09 84:4063 85:7c69 86:3e01 87:4063 88:
007f
ata1.04: ATA-7, max UDMA/133, 490234752 sectors: LBA48 NCQ (depth 31/32)
ata1.04: configured for UDMA/100
scsi1 : sata_sil24
ata2: SATA link down (SStatus 0 SControl 300)
scsi2 : sata_sil24
ata3: SATA link down (SStatus 0 SControl 300)
scsi3 : sata_sil24
ata4: SATA link down (SStatus 0 SControl 300)
  Vendor: ATA       Model: WDC WD360GD-00FN  Rev: 34.0
  Type:   Direct-Access                      ANSI SCSI revision: 05
SCSI device sda: 72303840 512-byte hdwr sectors (37020 MB)
sda: Write Protect is off
sda: Mode Sense: 00 3a 00 00
SCSI device sda: drive cache: write back
SCSI device sda: 72303840 512-byte hdwr sectors (37020 MB)
sda: Write Protect is off
sda: Mode Sense: 00 3a 00 00
SCSI device sda: drive cache: write back
 sda: sda1 sda2 sda3 sda4 < sda5 sda6 sda7 >
sd 0:0:0:0: Attached scsi disk sda
  Vendor: ATA       Model: ST3250824NS       Rev: 3.AE
  Type:   Direct-Access                      ANSI SCSI revision: 05
sd 0:0:0:0: Attached scsi generic sg0 type 0
SCSI device sdb: 488397168 512-byte hdwr sectors (250059 MB)
sdb: Write Protect is off
sdb: Mode Sense: 00 3a 00 00
SCSI device sdb: drive cache: write back
SCSI device sdb: 488397168 512-byte hdwr sectors (250059 MB)
sdb: Write Protect is off
sdb: Mode Sense: 00 3a 00 00
SCSI device sdb: drive cache: write back
 sdb: unknown partition table
sd 0:0:2:0: Attached scsi disk sdb
sd 0:0:2:0: Attached scsi generic sg1 type 0
  Vendor: ATA       Model: ST3250824NS       Rev: 3.AE
  Type:   Direct-Access                      ANSI SCSI revision: 05
SCSI device sdc: 488397168 512-byte hdwr sectors (250059 MB)
sdc: Write Protect is off
sdc: Mode Sense: 00 3a 00 00
SCSI device sdc: drive cache: write back
SCSI device sdc: 488397168 512-byte hdwr sectors (250059 MB)
sdc: Write Protect is off
sdc: Mode Sense: 00 3a 00 00
SCSI device sdc: drive cache: write back
 sdc: unknown partition table
sd 0:0:3:0: Attached scsi disk sdc
sd 0:0:3:0: Attached scsi generic sg2 type 0
  Vendor: ATA       Model: Maxtor 7L250S0    Rev: BANC
  Type:   Direct-Access                      ANSI SCSI revision: 05
SCSI device sdd: 490234752 512-byte hdwr sectors (251000 MB)
sdd: Write Protect is off
sdd: Mode Sense: 00 3a 00 00
SCSI device sdd: drive cache: write back
SCSI device sdd: 490234752 512-byte hdwr sectors (251000 MB)
sdd: Write Protect is off
sdd: Mode Sense: 00 3a 00 00
SCSI device sdd: drive cache: write back
 sdd: sdd1
sd 0:0:4:0: Attached scsi disk sdd
sd 0:0:4:0: Attached scsi generic sg3 type 0


[-- Attachment #2: libata-pm.c --]
[-- Type: application/octet-stream, Size: 24212 bytes --]

/*
 *  libata-pm.c - libata port multiplier support
 *
 *  Maintained by:  Jeff Garzik <jgarzik@pobox.com>
 *    		    Please ALWAYS copy linux-ide@vger.kernel.org
 *		    on emails.
 *
 *  Copyright 2006 Tejun Heo <htejun@gmail.com>
 *
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License as
 *  published by the Free Software Foundation; either version 2, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; see the file COPYING.  If not, write to
 *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139,
 *  USA.
 *
 *
 *  libata documentation is available via 'make {ps|pdf}docs',
 *  as Documentation/DocBook/libata.*
 *
 *  Hardware documentation available from http://www.t13.org/ and
 *  http://www.sata-io.org/
 *
 */

#include <linux/config.h>
#include <linux/kernel.h>

#include <linux/libata.h>

#include "libata.h"

/**
 *	ata_pm_read_init_tf - initialize TF for PM read
 *	@tf: taskfile to initialize
 *	@dev: PM dev
 *	@pmp: port multiplier port number
 *	@reg: register to read
 *
 *	Initialize @tf for PM read command.
 *
 *	LOCKING:
 *	None.
 */
void ata_pm_read_init_tf(struct ata_taskfile *tf,
			 struct ata_device *dev, int pmp, int reg)
{
	ata_tf_init(dev, tf);
	tf->command = ATA_CMD_PM_READ;
	tf->protocol = ATA_PROT_NODATA;
	tf->flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
	tf->feature = reg;
	tf->device = pmp;
}

/**
 *	ata_pm_read_val - extract PM read result from TF
 *	@tf: target TF
 *
 *	Determine PM read result from @tf.
 *
 *	LOCKING:
 *	None.
 */
u32 ata_pm_read_val(const struct ata_taskfile *tf)
{
	return tf->nsect | tf->lbal << 8 | tf->lbam << 16 | tf->lbah << 24;
}

/**
 *	ata_pm_read_init_tf - initialize TF for PM write
 *	@tf: taskfile to initialize
 *	@dev: PM dev
 *	@pmp: port multiplier port number
 *	@reg: register to read
 *	@val: value to write
 *
 *	Initialize @tf for PM write command.
 *
 *	LOCKING:
 *	None.
 */
void ata_pm_write_init_tf(struct ata_taskfile *tf,
			  struct ata_device *dev, int pmp, int reg, u32 val)
{
	ata_tf_init(dev, tf);
	tf->command = ATA_CMD_PM_WRITE;
	tf->protocol = ATA_PROT_NODATA;
	tf->flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
	tf->feature = reg;
	tf->device = pmp;
	tf->nsect = val & 0xff;
	tf->lbal = (val >> 8) & 0xff;
	tf->lbam = (val >> 16) & 0xff;
	tf->lbah = (val >> 24) & 0xff;
}

/**
 *	ata_pm_scr_read - read PSCR
 *	@link: ATA link to read PSCR for
 *	@reg: PSCR to read
 *	@r_val: resulting value
 *
 *	Read PSCR @reg into @r_val for @link, to be called from
 *	ata_scr_read().
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 *
 *	RETURNS:
 *	0 on success, -errno on failure.
 */
int ata_pm_scr_read(struct ata_link *link, int reg, u32 *r_val)
{
	struct ata_port *ap = link->ap;
	struct ata_device *pm_dev = ap->link.device;

	might_sleep();

	if (reg > ATA_PM_PSCR_CONTROL)
		return -EINVAL;

	return ap->ops->pm_read(pm_dev, link->pmp, reg, r_val);
}

/**
 *	ata_pm_scr_write - write PSCR
 *	@link: ATA link to write PSCR for
 *	@reg: PSCR to write
 *	@val: value to be written
 *
 *	Write @val to PSCR @reg for @link, to be called from
 *	ata_scr_write() and ata_scr_write_flush().
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 *
 *	RETURNS:
 *	0 on success, -errno on failure.
 */
int ata_pm_scr_write(struct ata_link *link, int reg, u32 val)
{
	struct ata_port *ap = link->ap;
	struct ata_device *pm_dev = ap->link.device;

	might_sleep();

	if (reg > ATA_PM_PSCR_CONTROL)
		return -EINVAL;

	return ap->ops->pm_write(pm_dev, link->pmp, reg, val);
}

/**
 *	ata_pm_std_prereset - prepare PM link for reset
 *	@link: link to be reset
 *
 *	@link is about to be reset.  Initialize it.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep)
 *
 *	RETURNS:
 *	0 on success, -errno otherwise.
 */
int ata_pm_std_prereset(struct ata_link *link)
{
	int rc;

	/* if we're about to do hardreset, don't bother */
	if (link->eh_context.i.action & ATA_EH_HARDRESET)
		return 0;

	/* resume link */
	rc = sata_link_resume(link, 1);
	if (rc) {
		/* phy resume failed */
		ata_link_printk(link, KERN_WARNING, "failed to resume link "
				"for reset (errno=%d)\n", rc);
		return rc;
	}

	/* clear SError bits including .X which blocks the port when set */
	rc = ata_scr_write(link, SCR_ERROR, 0xffffffff);
	if (rc) {
		ata_link_printk(link, KERN_ERR,
				"failed to clear SError (errno=%d)\n", rc);
		return rc;
	}

	return 0;
}

/**
 *	ata_pm_std_hardreset - standard hardreset method for PM link
 *	@link: link to be reset
 *
 *	Hardreset PM port @link.  Note that this function doesn't wait
 *	for BSY clearance.  There simply isn't a generic way to wait
 *	the event.  Instead, this function return -EAGAIN thus telling
 *	libata-EH to followup with softreset.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep)
 *
 *	RETURNS:
 *	0 on success, -errno otherwise.
 */
int ata_pm_std_hardreset(struct ata_link *link, unsigned int *class)
{
	int rc;

	DPRINTK("ENTER\n");

	/* reset */
	rc = sata_link_hardreset(link);
	if (rc)
		goto out;

	/* clear SError bits including .X which blocks the port when set */
	rc = ata_scr_write(link, SCR_ERROR, 0xffffffff);
	if (rc) {
		ata_link_printk(link, KERN_ERR, "failed to clear SError "
				"during hardreset (errno=%d)\n", rc);
		goto out;
	}

	/* follow up with softreset so that we can wait for !BSY */
	rc = -EAGAIN;
 out:
	DPRINTK("EXIT, rc=%d\n", rc);
	return rc;
}

/**
 *	ata_std_postreset - standard postreset method for PM link
 *	@link: the target ata_link
 *	@classes: classes of attached devices
 *
 *	This function is invoked after a successful reset.  Note that
 *	the device might have been reset more than once using
 *	different reset methods before postreset is invoked.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep)
 */
void ata_pm_std_postreset(struct ata_link *link, unsigned int *class)
{
	u32 serror;

	DPRINTK("ENTER\n");

	/* clear SError */
	if (ata_scr_read(link, SCR_ERROR, &serror) == 0)
		ata_scr_write(link, SCR_ERROR, serror);

	/* print link status */
	sata_print_link_status(link);

	DPRINTK("EXIT\n");
}

/**
 *	ata_pm_read_gscr - read GSCR block of SATA PM
 *	@dev: PM device
 *	@gscr: buffer to read GSCR block into
 *
 *	Read selected PM GSCRs from the PM at @dev.  This will serve
 *	as configuration and identification info for the PM.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 *
 *	RETURNS:
 *	0 on success, -errno on failure.
 */
static int ata_pm_read_gscr(struct ata_device *dev, u32 *gscr)
{
	static const int gscr_to_read[] = { 0, 1, 2, 32, 33, 64, 96 };
	struct ata_port *ap = dev->link->ap;
	int i, rc;

	for (i = 0; i < ARRAY_SIZE(gscr_to_read); i++) {
		int reg = gscr_to_read[i];

		rc = ap->ops->pm_read(dev, ATA_PM_CTRL_PORT, reg, &gscr[reg]);
		if (rc) {
			ata_dev_printk(dev, KERN_ERR, "failed to read "
				       "PM GSCR[%d] (errno=%d)\n", reg, rc);
			return rc;
		}
	}

	return 0;
}

static const char *ata_pm_spec_rev_str(const u32 *gscr)
{
	u32 rev = gscr[ATA_PM_GSCR_REV];

	if (rev & (1 << 2))
		return "1.1";
	if (rev & (1 << 1))
		return "1.0";
	return "<unknown>";
}

static void ata_pm_quirks(u32 *gscr, int *nr_ports, unsigned int *link_flags)
{
	u16 vendor = ata_pm_gscr_vendor(gscr);
	u16 devid = ata_pm_gscr_devid(gscr);

	/* Sil4726 reports two extra ports for configuration and
	 * enclosure processor, both of which are ignored ATM.  Also,
	 * it requires hardreset to resume PM links.
	 */
	if (vendor == 0x1095 && devid == 0x4726) {
		*nr_ports -= 2;
		*link_flags |= ATA_LFLAG_HRST_TO_RESUME;
	}

	/* Sil3726 reports one extra ports , which is ignored ATM.
	 * Also, it requires hardreset to resume PM links.
	 */
	if (vendor == 0x1095 && devid == 0x3726) {
		*nr_ports -= 1;
		*link_flags |= ATA_LFLAG_HRST_TO_RESUME;
	}
}

static int ata_pm_configure(struct ata_device *dev, int *r_nr_ports,
			    unsigned int *r_link_flags, int print_info)
{
	struct ata_link *link = dev->link;
	struct ata_port *ap = link->ap;
	u32 *gscr = dev->gscr;
	unsigned int link_flags;
	const char *reason;
	int nr_ports, rc;

	nr_ports = ata_pm_gscr_ports(gscr);
	link_flags = 0;

	ata_pm_quirks(gscr, &nr_ports, &link_flags);

	if (nr_ports <= 0 || nr_ports > ATA_PM_MAX_PORTS) {
		rc = -EINVAL;
		reason = "invalid nr_ports";
		goto fail;
	}

	rc = ap->ops->pm_write(dev, link->pmp, ATA_PM_GSCR_ERROR_EN,
			       SERR_PHYRDY_CHG | SERR_DEV_XCHG);
	if (rc) {
		reason = "failed to write GSCR_ERROR_EN";
		goto fail;
	}

	if (ap->flags & ATA_FLAG_SDB_NOTIFY &&
	    gscr[ATA_PM_GSCR_FEAT] & ATA_PM_FEAT_NOTIFY) {
		gscr[ATA_PM_GSCR_FEAT_EN] |= ATA_PM_FEAT_NOTIFY;

		rc = ap->ops->pm_write(dev, link->pmp, ATA_PM_GSCR_FEAT_EN,
				       gscr[ATA_PM_GSCR_FEAT_EN]);
		if (rc) {
			reason = "failed to write GSCR_FEAT_EN";
			goto fail;
		}
	}

	if (print_info)
		ata_dev_printk(dev, KERN_INFO, "Port Multiplier %s, "
			       "0x%04x:0x%04x r%d, %d ports, feat 0x%x/0x%x\n",
			       ata_pm_spec_rev_str(gscr),
			       ata_pm_gscr_vendor(gscr),
			       ata_pm_gscr_devid(gscr), ata_pm_gscr_rev(gscr),
			       nr_ports, gscr[ATA_PM_GSCR_FEAT_EN],
			       gscr[ATA_PM_GSCR_FEAT]);

	*r_nr_ports = nr_ports;
	*r_link_flags = link_flags;
	return 0;

 fail:
	ata_dev_printk(dev, KERN_ERR,
		       "failed to configure Port Multiplier (%s)\n", reason);
	return rc;
}

static int ata_pm_init_links(struct ata_port *ap, int nr_ports,
			     unsigned int link_flags)
{
	struct ata_link *pm_link = ap->pm_link;
	int i;

	if (!pm_link) {
		pm_link = kzalloc(sizeof(pm_link[0]) * ATA_PM_MAX_PORTS,
				  GFP_NOIO);
		if (!pm_link)
			return -ENOMEM;

		for (i = 0; i < ATA_PM_MAX_PORTS; i++)
			ata_link_init(ap, &pm_link[i], i);

		ap->pm_link = pm_link;
	}

	for (i = 0; i < nr_ports; i++) {
		struct ata_link *link = &pm_link[i];
		link->flags |= link_flags;
		link->reset_tries = ATA_EH_PM_RESET_TRIES;
		ata_link_init_probe(link);
	}

	return 0;
}

/**
 *	ata_pm_attach - attach a SATA PM device
 *	@dev: SATA PM device to attach
 *
 *	Configure and attach SATA PM device @dev.  This function is
 *	also responsible for allocating and initializing PM links.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 *
 *	RETURNS:
 *	0 on success, -errno on failure.
 */
int ata_pm_attach(struct ata_device *dev)
{
	struct ata_link *link = dev->link;
	struct ata_port *ap = link->ap;
	unsigned int link_flags;
	unsigned long flags;
	struct ata_link *tlink;
	int nr_ports, rc;

	/* is it haging off the right place? */
	if (!(ap->flags & ATA_FLAG_PM)) {
		ata_dev_printk(dev, KERN_ERR,
			       "host does not support Port Multiplier\n");
		return -EINVAL;
	}

	if (!ata_is_host_link(link)) {
		ata_dev_printk(dev, KERN_ERR,
			       "Port Multipliers cannot be nested\n");
		return -EINVAL;
	}

	if (dev->devno) {
		ata_dev_printk(dev, KERN_ERR,
			       "Port Multiplier must be the first device\n");
		return -EINVAL;
	}

	WARN_ON(link->pmp != 0);
	link->pmp = ATA_PM_CTRL_PORT;

	/* read GSCR block */
	rc = ata_pm_read_gscr(dev, dev->gscr);
	if (rc)
		goto fail;

	/* config PM */
	rc = ata_pm_configure(dev, &nr_ports, &link_flags, 1);
	if (rc)
		goto fail;

	rc = ata_pm_init_links(ap, nr_ports, link_flags);
	if (rc) {
		ata_dev_printk(dev, KERN_INFO,
			       "failed to initialize PM links\n");
		goto fail;
	}

	/* attach it */
	spin_lock_irqsave(&ap->host_set->lock, flags);
	WARN_ON(ap->nr_pm_links);
	ap->nr_pm_links = nr_ports;
	spin_unlock_irqrestore(&ap->host_set->lock, flags);

	if (ap->ops->pm_attach)
		ap->ops->pm_attach(ap);

	ata_port_for_each_link(tlink, ap)
		ata_link_init_sata_spd_limit(tlink);

	return 0;

 fail:
	link->pmp = 0;
	return rc;
}

/**
 *	ata_pm_detach - detach a SATA PM device
 *	@dev: SATA PM device to detach
 *
 *	Detach SATA PM device @dev.  This function is also responsible
 *	for deconfiguring PM links.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 */
void ata_pm_detach(struct ata_device *dev)
{
	struct ata_link *link = dev->link;
	struct ata_port *ap = link->ap;
	struct ata_link *tlink;
	unsigned long flags;

	ata_dev_printk(dev, KERN_INFO, "Port Multiplier detaching\n");

	WARN_ON(!ata_is_host_link(link) || dev->devno ||
		link->pmp != ATA_PM_CTRL_PORT);

	if (ap->ops->pm_detach)
		ap->ops->pm_detach(ap);

	ata_port_for_each_link(tlink, ap)
		ata_eh_detach_dev(tlink->device);

	spin_lock_irqsave(&ap->host_set->lock, flags);
	ap->nr_pm_links = 0;
	link->pmp = 0;
	spin_unlock_irqrestore(&ap->host_set->lock, flags);
}

/**
 *	ata_pm_same_pm - determine whether new GSCR matches the configured PM
 *	@dev: PM device to compare against
 *	@new_gscr: GSCR block of the new device
 *
 *	Compare @new_gscr against @dev and determine whether @dev is
 *	the PM described by @new_gscr.
 *
 *	LOCKING:
 *	None.
 *
 *	RETURNS:
 *	1 if @dev matches @new_gscr, 0 otherwise.
 */
static int ata_pm_same_pm(struct ata_device *dev, const u32 *new_gscr)
{
	const u32 *old_gscr = dev->gscr;
	u16 old_vendor, new_vendor, old_devid, new_devid;
	int old_nr_ports, new_nr_ports;

	old_vendor = ata_pm_gscr_vendor(old_gscr);
	new_vendor = ata_pm_gscr_vendor(new_gscr);
	old_devid = ata_pm_gscr_devid(old_gscr);
	new_devid = ata_pm_gscr_devid(new_gscr);
	old_nr_ports = ata_pm_gscr_ports(old_gscr);
	new_nr_ports = ata_pm_gscr_ports(new_gscr);

	if (old_vendor != new_vendor) {
		ata_dev_printk(dev, KERN_INFO, "Port Multiplier "
			       "vendor mismatch '0x%x' != '0x%x'\n",
			       old_vendor, new_vendor);
		return 0;
	}

	if (old_devid != new_devid) {
		ata_dev_printk(dev, KERN_INFO, "Port Multiplier "
			       "device ID mismatch '0x%x' != '0x%x'\n",
			       old_devid, new_devid);
		return 0;
	}

	if (old_nr_ports != new_nr_ports) {
		ata_dev_printk(dev, KERN_INFO, "Port Multiplier "
			       "nr_ports mismatch '0x%x' != '0x%x'\n",
			       old_nr_ports, new_nr_ports);
		return 0;
	}

	return 1;
}

/**
 *	ata_pm_revalidate - revalidate SATA PM
 *	@dev: PM device to revalidate
 *	@new_class: new class code
 *
 *	Re-read GSCR block and make sure @dev is still attached to the
 *	port and properly configured.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 *
 *	RETURNS:
 *	0 on success, -errno otherwise.
 */
static int ata_pm_revalidate(struct ata_device *dev, unsigned int new_class)
{
	struct ata_link *link = dev->link;
	struct ata_port *ap = link->ap;
	u32 *gscr = (void *)ap->sector_buf;
	unsigned int link_flags;
	int nr_ports, rc;

	DPRINTK("ENTER\n");

	ata_eh_about_to_do(link, ATA_EH_REVALIDATE);

	if (!ata_dev_enabled(dev)) {
		rc = -ENODEV;
		goto fail;
	}

	/* sometimes wrong class is reported, let it retry */
	if (ata_class_enabled(new_class) && new_class != ATA_DEV_PM) {
		rc = -EIO;
		goto fail;
	}

	/* read GSCR */
	rc = ata_pm_read_gscr(dev, gscr);
	if (rc)
		goto fail;

	/* is the pm still there? */
	if (!ata_pm_same_pm(dev, gscr)) {
		rc = -ENODEV;
		goto fail;
	}

	memcpy(dev->gscr, gscr, sizeof(gscr[0]) * ATA_PM_GSCR_DWORDS);

	rc = ata_pm_configure(dev, &nr_ports, &link_flags, 0);
	if (rc)
		goto fail;

	if (nr_ports != ap->nr_pm_links) {
		rc = -ENODEV;
		goto fail;
	}

	link->eh_context.i.action &= ~ATA_EH_REVALIDATE;

	DPRINTK("EXIT, rc=0\n");
	return 0;

 fail:
	ata_dev_printk(dev, KERN_ERR,
		       "PM revalidation failed (errno=%d)\n", rc);
	DPRINTK("EXIT, rc=%d\n", rc);
	return rc;
}

/**
 *	ata_pm_revalidate_quick - revalidate SATA PM quickly
 *	@dev: PM device to revalidate
 *
 *	Make sure the attached PM is accessible.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 *
 *	RETURNS:
 *	0 on success, -errno otherwise.
 */
static int ata_pm_revalidate_quick(struct ata_device *dev)
{
	struct ata_port *ap = dev->link->ap;
	u32 prod_id;
	int rc;

	rc = ap->ops->pm_read(dev, ATA_PM_CTRL_PORT, ATA_PM_GSCR_PROD_ID,
			      &prod_id);
	if (rc) {
		ata_dev_printk(dev, KERN_ERR, "failed to read PM product ID\n");
		return rc;
	}

	if (prod_id != dev->gscr[ATA_PM_GSCR_PROD_ID]) {
		ata_dev_printk(dev, KERN_ERR, "PM product ID mismatch\n");
		/* something weird is going on, request full PM recovery */
		return -EIO;
	}

	return 0;
}

/**
 *	ata_pm_eh_recover_pm - recover PM
 *	@ap: ATA port PM is attached to
 *	@prereset: prereset method (can be NULL)
 *	@softreset: softreset method
 *	@hardreset: hardreset method
 *	@postreset: postreset method (can be NULL)
 *	@link_tries: link tries left
 *
 *	Recover PM attached to @ap.  Recovery procedure is somewhat
 *	similar to that of ata_eh_recover() except that reset should
 *	always be performed in hard->soft sequence and recovery
 *	failure results in PM detachment.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 *
 *	RETURNS:
 *	0 on success, -errno on failure.
 */
static int ata_pm_eh_recover_pm(struct ata_port *ap, ata_prereset_fn_t prereset,
				ata_reset_fn_t softreset,
				ata_reset_fn_t hardreset,
				ata_postreset_fn_t postreset, int *link_tries)
{
	struct ata_link *link = &ap->link;
	struct ata_eh_context *ehc = &link->eh_context;
	struct ata_device *dev = link->device;
	int tries = link->reset_tries;
	int detach = 0, probe = 0, rc = 0;

	DPRINTK("ENTER\n");

	if (dev->flags & ATA_DFLAG_DETACH) {
		detach = 1;
		goto fail;
	}

 retry:
	ehc->classes[0] = ATA_DEV_UNKNOWN;

	if (ehc->i.action & ATA_EH_RESET_MASK) {
		struct ata_link *tlink;

		ata_eh_freeze_port(ap);

		/* reset */
		ehc->i.action = ATA_EH_HARDRESET;
		rc = ata_eh_reset(link, 0, prereset, softreset, hardreset,
				  postreset);
		if (rc) {
			ata_link_printk(link, KERN_ERR,
					"failed to reset PM, giving up\n");
			goto fail;
		}

		ata_eh_thaw_port(ap);

		ata_port_for_each_link(tlink, ap) {
			struct ata_eh_context *tehc = &tlink->eh_context;

			if (link_tries[tlink->pmp])
				tehc->i.action = ata_link_resume_action(tlink);
			else
				tehc->i.action = 0;
		}
	}

	/* If revalidation is requested, revalidate and reconfigure;
	 * otherwise, do quick revalidation.
	 */
	if (ehc->i.action & ATA_EH_REVALIDATE)
		rc = ata_pm_revalidate(dev, ehc->classes[0]);
	else
		rc = ata_pm_revalidate_quick(dev);

	if (rc == -ENODEV) {
		probe = 1;
		goto fail;
	} else if (rc) {
		if (--tries) {
			int sleep = ehc->flags & ATA_EHC_DID_RESET;

			ata_dev_printk(dev, KERN_WARNING,
				       "retrying hardreset%s\n",
				       sleep ? " in 5 secs" : "");
			if (sleep)
				ssleep(5);
			ehc->i.action |= ATA_EH_HARDRESET;
			goto retry;
		} else {
			ata_dev_printk(dev, KERN_ERR, "failed to recover PM "
				       "after %d resets, giving up\n",
				       link->reset_tries);
			goto fail;
		}
	}

	/* okay, PM resurrected */
	ehc->flags &= ~ATA_EHC_DID_RESET;
	ehc->i.action = 0;

	DPRINTK("EXIT, rc=0\n");
	return 0;

 fail:
	ata_pm_detach(dev);
	if (probe || detach) {
		ata_eh_detach_dev(dev);
		if (probe)
			ehc->i.probe_mask |= 1;
	} else
		ata_dev_disable(dev);

	DPRINTK("EXIT, rc=%d\n", rc);
	return rc;
}

/**
 *	ata_pm_eh_recover - recover PM-enabled port
 *	@ap: ATA port to recover
 *	@prereset: prereset method (can be NULL)
 *	@softreset: softreset method
 *	@hardreset: hardreset method
 *	@postreset: postreset method (can be NULL)
 *	@pm_prereset: PM prereset method (can be NULL)
 *	@pm_softreset: PM softreset method (can be NULL)
 *	@pm_hardreset: PM hardreset method (can be NULL)
 *	@pm_postreset: PM postreset method (can be NULL)
 *
 *	Drive EH recovery operation for PM enable port @ap.  This
 *	function recovers host and PM ports with proper retrials and
 *	fallbacks.  Actual recovery operations are performed using
 *	ata_eh_recover() and ata_pm_eh_recover_pm().
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 *
 *	RETURNS:
 *	0 on success, -errno on failure.
 */
static int ata_pm_eh_recover(struct ata_port *ap,
		ata_prereset_fn_t prereset, ata_reset_fn_t softreset,
		ata_reset_fn_t hardreset, ata_postreset_fn_t postreset,
		ata_prereset_fn_t pm_prereset, ata_reset_fn_t pm_softreset,
		ata_reset_fn_t pm_hardreset, ata_postreset_fn_t pm_postreset)
{
	int pm_tries, link_tries[ATA_PM_MAX_PORTS];
	struct ata_link *pm_link = &ap->link;
	struct ata_device *pm_dev = pm_link->device;
	struct ata_eh_info *pm_ehi = &pm_link->eh_context.i;
	struct ata_link *link;
	struct ata_device *dev;
	u32 gscr_error;
	int cnt, rc;

	pm_tries = ATA_EH_PM_TRIES;
	ata_port_for_each_link(link, ap)
		link_tries[link->pmp] = ATA_EH_PM_LINK_TRIES;

 retry:
	/* PM attached? */
	if (!ap->nr_pm_links) {
		rc = ata_eh_recover(ap, prereset, softreset, hardreset,
				    postreset, NULL);
		if (rc) {
			ata_link_for_each_dev(dev, &ap->link)
				ata_dev_disable(dev);
			return rc;
		}

		if (pm_dev->class != ATA_DEV_PM)
			return 0;

		/* new PM online */
		ata_port_for_each_link(link, ap)
			link_tries[link->pmp] = ATA_EH_PM_LINK_TRIES;

		/* fall through */
	}

	/* recover pm */
	rc = ata_pm_eh_recover_pm(ap, prereset, softreset, hardreset, postreset,
				  link_tries);
	if (rc)
		goto pm_retry;

	/* recover links */
	rc = ata_eh_recover(ap, pm_prereset, pm_softreset, pm_hardreset,
			    pm_postreset, &link);
	if (rc)
		goto link_retry;

	/* Connection status might have changed while resetting other
	 * links, check ATA_PM_GSCR_ERROR before returning.
	 */

	/* clear snotification */
	ata_scr_write(pm_link, SCR_NOTIFICATION, (1 << ap->nr_pm_links) - 1);

	/* check GSCR_ERROR */
	rc = ap->ops->pm_read(pm_dev, pm_link->pmp, ATA_PM_GSCR_ERROR,
			      &gscr_error);
	if (rc) {
		ata_dev_printk(pm_dev, KERN_ERR,
			       "failed to read PM_GSCR_ERROR\n");
		goto pm_retry;
	}

	cnt = 0;
	ata_port_for_each_link(link, ap) {
		struct ata_eh_info *ehi = &link->eh_context.i;

		if (gscr_error & (1 << link->pmp) &&
		    link_tries[link->pmp] && --link_tries[link->pmp]) {
			ehi->probe_mask |= 1;
			ehi->action = ata_link_resume_action(link);
			cnt++;
		}
	}

	if (cnt) {
		ata_port_printk(ap, KERN_INFO, "PM SError.N/X set for some "
				"ports, repeating recovery\n");
		goto retry;
	}

	return 0;

 link_retry:
	if (link_tries[link->pmp] && --link_tries[link->pmp]) {
		ata_link_printk(link, KERN_WARNING,
				"failed to recover link, resetting PM\n");
		pm_ehi->action |= ATA_EH_HARDRESET;
		goto retry;
	}

	/* give up this link */
	ata_link_printk(link, KERN_ERR,
			"failed to recover link after %d tries, giving up\n",
			ATA_EH_PM_LINK_TRIES);
	ata_dev_disable(link->device);
	link->eh_context.i.action = 0;

	/* fall through */
 pm_retry:
	/* Control always ends up here after detaching PM.  Shut up
	 * and return if we're unloading.
	 */
	if (ap->flags & ATA_FLAG_UNLOADING)
		return rc;

	if (!ap->nr_pm_links)
		goto retry;

	if (--pm_tries) {
		ata_port_printk(ap, KERN_WARNING,
				"failed to recover PM, retrying in 5 secs\n");
		pm_ehi->action |= ATA_EH_HARDRESET;
		ssleep(5);
		goto retry;
	}

	ata_port_printk(ap, KERN_ERR,
			"failed to recover PM after %d tries, giving up\n",
			ATA_EH_PM_TRIES);
	ata_pm_detach(pm_dev);

	return rc;
}

/**
 *	ata_pm_do_eh - do standard error handling for PM-enabled host
 *	@ap: host port to handle error for
 *	@prereset: prereset method (can be NULL)
 *	@softreset: softreset method
 *	@hardreset: hardreset method
 *	@postreset: postreset method (can be NULL)
 *	@pm_prereset: PM prereset method (can be NULL)
 *	@pm_softreset: PM softreset method (can be NULL)
 *	@pm_hardreset: PM hardreset method (can be NULL)
 *	@pm_postreset: PM postreset method (can be NULL)
 *
 *	Perform standard error handling sequence for PM-enabled host
 *	@ap.
 *
 *	LOCKING:
 *	Kernel thread context (may sleep).
 */
void ata_pm_do_eh(struct ata_port *ap,
		  ata_prereset_fn_t prereset, ata_reset_fn_t softreset,
		  ata_reset_fn_t hardreset, ata_postreset_fn_t postreset,
		  ata_prereset_fn_t pm_prereset, ata_reset_fn_t pm_softreset,
		  ata_reset_fn_t pm_hardreset, ata_postreset_fn_t pm_postreset)
{
	if (!(ap->flags & (ATA_FLAG_LOADING | ATA_FLAG_UNLOADING))) {
		ata_eh_autopsy(ap);
		ata_eh_report(ap);
	}

	ata_pm_eh_recover(ap, prereset, softreset, hardreset, postreset,
			  pm_prereset, pm_softreset, pm_hardreset,
			  pm_postreset);

	ata_eh_finish(ap);
}