// SPDX-License-Identifier: GPL-2.0-only

  /*
   * libata-pmp.c - libata port multiplier support
   *
   * Copyright (c) 2007  SUSE Linux Products GmbH
   * Copyright (c) 2007  Tejun Heo <teheo@suse.de>

   */
  
  #include <linux/kernel.h>

  #include <linux/export.h>

  #include <linux/libata.h>

  #include <linux/slab.h>

  #include "libata.h"

  #include "libata-transport.h"

  const struct ata_port_operations sata_pmp_port_ops = {
  	.inherits		= &sata_port_ops,
  	.pmp_prereset		= ata_std_prereset,
  	.pmp_hardreset		= sata_std_hardreset,
  	.pmp_postreset		= ata_std_postreset,
  	.error_handler		= sata_pmp_error_handler,
  };

  /**
   *	sata_pmp_read - read PMP register
   *	@link: link to read PMP register for
   *	@reg: register to read
   *	@r_val: resulting value
   *

   *	Read PMP register.

   *
   *	LOCKING:
   *	Kernel thread context (may sleep).
   *
   *	RETURNS:

   *	0 on success, AC_ERR_* mask on failure.

   */

  static unsigned int sata_pmp_read(struct ata_link *link, int reg, u32 *r_val)

  {
  	struct ata_port *ap = link->ap;
  	struct ata_device *pmp_dev = ap->link.device;

  	struct ata_taskfile tf;
  	unsigned int err_mask;
  
  	ata_tf_init(pmp_dev, &tf);
  	tf.command = ATA_CMD_PMP_READ;
  	tf.protocol = ATA_PROT_NODATA;

  	tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE | ATA_TFLAG_LBA48;

  	tf.feature = reg;
  	tf.device = link->pmp;
  
  	err_mask = ata_exec_internal(pmp_dev, &tf, NULL, DMA_NONE, NULL, 0,

  				     SATA_PMP_RW_TIMEOUT);

  	if (err_mask)
  		return err_mask;
  
  	*r_val = tf.nsect | tf.lbal << 8 | tf.lbam << 16 | tf.lbah << 24;
  	return 0;

  }
  
  /**
   *	sata_pmp_write - write PMP register
   *	@link: link to write PMP register for
   *	@reg: register to write
   *	@r_val: value to write
   *

   *	Write PMP register.

   *
   *	LOCKING:
   *	Kernel thread context (may sleep).
   *
   *	RETURNS:

   *	0 on success, AC_ERR_* mask on failure.

   */

  static unsigned int sata_pmp_write(struct ata_link *link, int reg, u32 val)

  {
  	struct ata_port *ap = link->ap;
  	struct ata_device *pmp_dev = ap->link.device;

  	struct ata_taskfile tf;
  
  	ata_tf_init(pmp_dev, &tf);
  	tf.command = ATA_CMD_PMP_WRITE;
  	tf.protocol = ATA_PROT_NODATA;

  	tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE | ATA_TFLAG_LBA48;

  	tf.feature = reg;
  	tf.device = link->pmp;
  	tf.nsect = val & 0xff;
  	tf.lbal = (val >> 8) & 0xff;
  	tf.lbam = (val >> 16) & 0xff;
  	tf.lbah = (val >> 24) & 0xff;
  
  	return ata_exec_internal(pmp_dev, &tf, NULL, DMA_NONE, NULL, 0,

  				 SATA_PMP_RW_TIMEOUT);

  }
  
  /**

   *	sata_pmp_qc_defer_cmd_switch - qc_defer for command switching PMP
   *	@qc: ATA command in question
   *
   *	A host which has command switching PMP support cannot issue
   *	commands to multiple links simultaneously.
   *
   *	LOCKING:
   *	spin_lock_irqsave(host lock)
   *
   *	RETURNS:
   *	ATA_DEFER_* if deferring is needed, 0 otherwise.
   */
  int sata_pmp_qc_defer_cmd_switch(struct ata_queued_cmd *qc)
  {
  	struct ata_link *link = qc->dev->link;
  	struct ata_port *ap = link->ap;
  
  	if (ap->excl_link == NULL || ap->excl_link == link) {
  		if (ap->nr_active_links == 0 || ata_link_active(link)) {
  			qc->flags |= ATA_QCFLAG_CLEAR_EXCL;
  			return ata_std_qc_defer(qc);
  		}
  
  		ap->excl_link = link;
  	}
  
  	return ATA_DEFER_PORT;
  }
  
  /**

   *	sata_pmp_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 sata_pmp_scr_read(struct ata_link *link, int reg, u32 *r_val)
  {

  	unsigned int err_mask;

  	if (reg > SATA_PMP_PSCR_CONTROL)
  		return -EINVAL;

  	err_mask = sata_pmp_read(link, reg, r_val);
  	if (err_mask) {

  		ata_link_warn(link, "failed to read SCR %d (Emask=0x%x)
  ",
  			      reg, err_mask);

  		return -EIO;
  	}
  	return 0;

  }
  
  /**
   *	sata_pmp_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 sata_pmp_scr_write(struct ata_link *link, int reg, u32 val)
  {

  	unsigned int err_mask;

  	if (reg > SATA_PMP_PSCR_CONTROL)
  		return -EINVAL;

  	err_mask = sata_pmp_write(link, reg, val);
  	if (err_mask) {

  		ata_link_warn(link, "failed to write SCR %d (Emask=0x%x)
  ",
  			      reg, err_mask);

  		return -EIO;
  	}
  	return 0;

  }
  
  /**

   *	sata_pmp_set_lpm - configure LPM for a PMP link
   *	@link: PMP link to configure LPM for
   *	@policy: target LPM policy
   *	@hints: LPM hints
   *
   *	Configure LPM for @link.  This function will contain any PMP
   *	specific workarounds if necessary.
   *
   *	LOCKING:
   *	EH context.
   *
   *	RETURNS:
   *	0 on success, -errno on failure.
   */
  int sata_pmp_set_lpm(struct ata_link *link, enum ata_lpm_policy policy,
  		     unsigned hints)
  {
  	return sata_link_scr_lpm(link, policy, true);
  }
  
  /**

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

  	int i;

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

  		unsigned int err_mask;

  		err_mask = sata_pmp_read(dev->link, reg, &gscr[reg]);
  		if (err_mask) {

  			ata_dev_err(dev, "failed to read PMP GSCR[%d] (Emask=0x%x)
  ",
  				    reg, err_mask);

  			return -EIO;

  		}
  	}
  
  	return 0;
  }
  
  static const char *sata_pmp_spec_rev_str(const u32 *gscr)
  {
  	u32 rev = gscr[SATA_PMP_GSCR_REV];

  	if (rev & (1 << 3))
  		return "1.2";

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

  #define PMP_GSCR_SII_POL 129

  static int sata_pmp_configure(struct ata_device *dev, int print_info)
  {
  	struct ata_port *ap = dev->link->ap;
  	u32 *gscr = dev->gscr;

  	u16 vendor = sata_pmp_gscr_vendor(gscr);
  	u16 devid = sata_pmp_gscr_devid(gscr);

  	unsigned int err_mask = 0;

  	const char *reason;
  	int nr_ports, rc;
  
  	nr_ports = sata_pmp_gscr_ports(gscr);
  
  	if (nr_ports <= 0 || nr_ports > SATA_PMP_MAX_PORTS) {
  		rc = -EINVAL;
  		reason = "invalid nr_ports";
  		goto fail;
  	}
  
  	if ((ap->flags & ATA_FLAG_AN) &&
  	    (gscr[SATA_PMP_GSCR_FEAT] & SATA_PMP_FEAT_NOTIFY))
  		dev->flags |= ATA_DFLAG_AN;
  
  	/* monitor SERR_PHYRDY_CHG on fan-out ports */

  	err_mask = sata_pmp_write(dev->link, SATA_PMP_GSCR_ERROR_EN,
  				  SERR_PHYRDY_CHG);
  	if (err_mask) {
  		rc = -EIO;

  		reason = "failed to write GSCR_ERROR_EN";
  		goto fail;
  	}

  	/* Disable sending Early R_OK.
  	 * With "cached read" HDD testing and multiple ports busy on a SATA

  	 * host controller, 3x26 PMP will very rarely drop a deferred

  	 * R_OK that was intended for the host. Symptom will be all
  	 * 5 drives under test will timeout, get reset, and recover.
  	 */

  	if (vendor == 0x1095 && (devid == 0x3726 || devid == 0x3826)) {

  		u32 reg;
  
  		err_mask = sata_pmp_read(&ap->link, PMP_GSCR_SII_POL, &reg);
  		if (err_mask) {
  			rc = -EIO;

  			reason = "failed to read Sil3x26 Private Register";

  			goto fail;
  		}
  		reg &= ~0x1;
  		err_mask = sata_pmp_write(&ap->link, PMP_GSCR_SII_POL, reg);
  		if (err_mask) {
  			rc = -EIO;

  			reason = "failed to write Sil3x26 Private Register";

  			goto fail;
  		}
  	}

  	if (print_info) {

  		ata_dev_info(dev, "Port Multiplier %s, "
  			     "0x%04x:0x%04x r%d, %d ports, feat 0x%x/0x%x
  ",
  			     sata_pmp_spec_rev_str(gscr), vendor, devid,
  			     sata_pmp_gscr_rev(gscr),
  			     nr_ports, gscr[SATA_PMP_GSCR_FEAT_EN],
  			     gscr[SATA_PMP_GSCR_FEAT]);

  
  		if (!(dev->flags & ATA_DFLAG_AN))

  			ata_dev_info(dev,

  				"Asynchronous notification not supported, "

  				"hotplug won't work on fan-out ports. Use warm-plug instead.
  ");

  	}
  
  	return 0;
  
   fail:

  	ata_dev_err(dev,
  		    "failed to configure Port Multiplier (%s, Emask=0x%x)
  ",
  		    reason, err_mask);

  	return rc;
  }

  static int sata_pmp_init_links (struct ata_port *ap, int nr_ports)

  {
  	struct ata_link *pmp_link = ap->pmp_link;

  	int i, err;

  
  	if (!pmp_link) {

  		pmp_link = kcalloc(SATA_PMP_MAX_PORTS, sizeof(pmp_link[0]),

  				   GFP_NOIO);
  		if (!pmp_link)
  			return -ENOMEM;
  
  		for (i = 0; i < SATA_PMP_MAX_PORTS; i++)
  			ata_link_init(ap, &pmp_link[i], i);
  
  		ap->pmp_link = pmp_link;

  
  		for (i = 0; i < SATA_PMP_MAX_PORTS; i++) {
  			err = ata_tlink_add(&pmp_link[i]);
  			if (err) {
  				goto err_tlink;
  			}
  		}

  	}
  
  	for (i = 0; i < nr_ports; i++) {
  		struct ata_link *link = &pmp_link[i];
  		struct ata_eh_context *ehc = &link->eh_context;
  
  		link->flags = 0;

  		ehc->i.probe_mask |= ATA_ALL_DEVICES;

  		ehc->i.action |= ATA_EH_RESET;

  	}
  
  	return 0;

    err_tlink:
  	while (--i >= 0)
  		ata_tlink_delete(&pmp_link[i]);
  	kfree(pmp_link);
  	ap->pmp_link = NULL;
  	return err;

  }
  
  static void sata_pmp_quirks(struct ata_port *ap)
  {
  	u32 *gscr = ap->link.device->gscr;
  	u16 vendor = sata_pmp_gscr_vendor(gscr);
  	u16 devid = sata_pmp_gscr_devid(gscr);
  	struct ata_link *link;

  	if (vendor == 0x1095 && (devid == 0x3726 || devid == 0x3826)) {
  		/* sil3x26 quirks */

  		ata_for_each_link(link, ap, EDGE) {

  			/* link reports offline after LPM */
  			link->flags |= ATA_LFLAG_NO_LPM;

  			/*
  			 * Class code report is unreliable and SRST times
  			 * out under certain configurations.
  			 */

  			if (link->pmp < 5)

  				link->flags |= ATA_LFLAG_NO_SRST |
  					       ATA_LFLAG_ASSUME_ATA;

  
  			/* port 5 is for SEMB device and it doesn't like SRST */
  			if (link->pmp == 5)
  				link->flags |= ATA_LFLAG_NO_SRST |
  					       ATA_LFLAG_ASSUME_SEMB;
  		}
  	} else if (vendor == 0x1095 && devid == 0x4723) {

  		/*
  		 * sil4723 quirks
  		 *
  		 * Link reports offline after LPM.  Class code report is
  		 * unreliable.  SIMG PMPs never got SRST reliable and the
  		 * config device at port 2 locks up on SRST.
  		 */
  		ata_for_each_link(link, ap, EDGE)
  			link->flags |= ATA_LFLAG_NO_LPM |
  				       ATA_LFLAG_NO_SRST |
  				       ATA_LFLAG_ASSUME_ATA;

  	} else if (vendor == 0x1095 && devid == 0x4726) {
  		/* sil4726 quirks */

  		ata_for_each_link(link, ap, EDGE) {

  			/* link reports offline after LPM */
  			link->flags |= ATA_LFLAG_NO_LPM;

  			/* Class code report is unreliable and SRST
  			 * times out under certain configurations.
  			 * Config device can be at port 0 or 5 and
  			 * locks up on SRST.

  			 */

  			if (link->pmp <= 5)

  				link->flags |= ATA_LFLAG_NO_SRST |
  					       ATA_LFLAG_ASSUME_ATA;
  
  			/* Port 6 is for SEMB device which doesn't
  			 * like SRST either.
  			 */
  			if (link->pmp == 6)
  				link->flags |= ATA_LFLAG_NO_SRST |
  					       ATA_LFLAG_ASSUME_SEMB;
  		}
  	} else if (vendor == 0x1095 && (devid == 0x5723 || devid == 0x5733 ||
  					devid == 0x5734 || devid == 0x5744)) {
  		/* sil5723/5744 quirks */
  
  		/* sil5723/5744 has either two or three downstream
  		 * ports depending on operation mode.  The last port
  		 * is empty if any actual IO device is available or
  		 * occupied by a pseudo configuration device
  		 * otherwise.  Don't try hard to recover it.
  		 */
  		ap->pmp_link[ap->nr_pmp_links - 1].flags |= ATA_LFLAG_NO_RETRY;

  	} else if (vendor == 0x197b && (devid == 0x2352 || devid == 0x0325)) {
  		/*
  		 * 0x2352: found in Thermaltake BlackX Duet, jmicron JMB350?
  		 * 0x0325: jmicron JMB394.
  		 */

  		ata_for_each_link(link, ap, EDGE) {
  			/* SRST breaks detection and disks get misclassified
  			 * LPM disabled to avoid potential problems
  			 */
  			link->flags |= ATA_LFLAG_NO_LPM |
  				       ATA_LFLAG_NO_SRST |
  				       ATA_LFLAG_ASSUME_ATA;
  		}

  	} else if (vendor == 0x11ab && devid == 0x4140) {
  		/* Marvell 4140 quirks */
  		ata_for_each_link(link, ap, EDGE) {
  			/* port 4 is for SEMB device and it doesn't like SRST */
  			if (link->pmp == 4)
  				link->flags |= ATA_LFLAG_DISABLED;
  		}

  	}
  }
  
  /**
   *	sata_pmp_attach - attach a SATA PMP device
   *	@dev: SATA PMP device to attach
   *
   *	Configure and attach SATA PMP device @dev.  This function is
   *	also responsible for allocating and initializing PMP links.
   *
   *	LOCKING:
   *	Kernel thread context (may sleep).
   *
   *	RETURNS:
   *	0 on success, -errno on failure.
   */
  int sata_pmp_attach(struct ata_device *dev)
  {
  	struct ata_link *link = dev->link;
  	struct ata_port *ap = link->ap;
  	unsigned long flags;
  	struct ata_link *tlink;
  	int rc;
  
  	/* is it hanging off the right place? */

  	if (!sata_pmp_supported(ap)) {

  		ata_dev_err(dev, "host does not support Port Multiplier
  ");

  		return -EINVAL;
  	}
  
  	if (!ata_is_host_link(link)) {

  		ata_dev_err(dev, "Port Multipliers cannot be nested
  ");

  		return -EINVAL;
  	}
  
  	if (dev->devno) {

  		ata_dev_err(dev, "Port Multiplier must be the first device
  ");

  		return -EINVAL;
  	}
  
  	WARN_ON(link->pmp != 0);
  	link->pmp = SATA_PMP_CTRL_PORT;
  
  	/* read GSCR block */
  	rc = sata_pmp_read_gscr(dev, dev->gscr);
  	if (rc)
  		goto fail;
  
  	/* config PMP */
  	rc = sata_pmp_configure(dev, 1);
  	if (rc)
  		goto fail;
  
  	rc = sata_pmp_init_links(ap, sata_pmp_gscr_ports(dev->gscr));
  	if (rc) {

  		ata_dev_info(dev, "failed to initialize PMP links
  ");

  		goto fail;
  	}
  
  	/* attach it */
  	spin_lock_irqsave(ap->lock, flags);
  	WARN_ON(ap->nr_pmp_links);
  	ap->nr_pmp_links = sata_pmp_gscr_ports(dev->gscr);
  	spin_unlock_irqrestore(ap->lock, flags);
  
  	sata_pmp_quirks(ap);
  
  	if (ap->ops->pmp_attach)
  		ap->ops->pmp_attach(ap);

  	ata_for_each_link(tlink, ap, EDGE)

  		sata_link_init_spd(tlink);
  
  	return 0;
  
   fail:
  	link->pmp = 0;
  	return rc;
  }
  
  /**
   *	sata_pmp_detach - detach a SATA PMP device
   *	@dev: SATA PMP device to detach
   *
   *	Detach SATA PMP device @dev.  This function is also
   *	responsible for deconfiguring PMP links.
   *
   *	LOCKING:
   *	Kernel thread context (may sleep).
   */
  static void sata_pmp_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_info(dev, "Port Multiplier detaching
  ");

  
  	WARN_ON(!ata_is_host_link(link) || dev->devno ||
  		link->pmp != SATA_PMP_CTRL_PORT);
  
  	if (ap->ops->pmp_detach)
  		ap->ops->pmp_detach(ap);

  	ata_for_each_link(tlink, ap, EDGE)

  		ata_eh_detach_dev(tlink->device);
  
  	spin_lock_irqsave(ap->lock, flags);
  	ap->nr_pmp_links = 0;
  	link->pmp = 0;
  	spin_unlock_irqrestore(ap->lock, flags);
  }
  
  /**
   *	sata_pmp_same_pmp - does new GSCR matches the configured PMP?
   *	@dev: PMP device to compare against
   *	@new_gscr: GSCR block of the new device
   *
   *	Compare @new_gscr against @dev and determine whether @dev is
   *	the PMP described by @new_gscr.
   *
   *	LOCKING:
   *	None.
   *
   *	RETURNS:
   *	1 if @dev matches @new_gscr, 0 otherwise.
   */
  static int sata_pmp_same_pmp(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 = sata_pmp_gscr_vendor(old_gscr);
  	new_vendor = sata_pmp_gscr_vendor(new_gscr);
  	old_devid = sata_pmp_gscr_devid(old_gscr);
  	new_devid = sata_pmp_gscr_devid(new_gscr);
  	old_nr_ports = sata_pmp_gscr_ports(old_gscr);
  	new_nr_ports = sata_pmp_gscr_ports(new_gscr);
  
  	if (old_vendor != new_vendor) {

  		ata_dev_info(dev,
  			     "Port Multiplier vendor mismatch '0x%x' != '0x%x'
  ",
  			     old_vendor, new_vendor);

  		return 0;
  	}
  
  	if (old_devid != new_devid) {

  		ata_dev_info(dev,
  			     "Port Multiplier device ID mismatch '0x%x' != '0x%x'
  ",
  			     old_devid, new_devid);

  		return 0;
  	}
  
  	if (old_nr_ports != new_nr_ports) {

  		ata_dev_info(dev,
  			     "Port Multiplier nr_ports mismatch '0x%x' != '0x%x'
  ",
  			     old_nr_ports, new_nr_ports);

  		return 0;
  	}
  
  	return 1;
  }
  
  /**
   *	sata_pmp_revalidate - revalidate SATA PMP
   *	@dev: PMP 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 sata_pmp_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;
  	int rc;
  
  	DPRINTK("ENTER
  ");
  
  	ata_eh_about_to_do(link, NULL, ATA_EH_REVALIDATE);
  
  	if (!ata_dev_enabled(dev)) {
  		rc = -ENODEV;
  		goto fail;
  	}
  
  	/* wrong class? */
  	if (ata_class_enabled(new_class) && new_class != ATA_DEV_PMP) {
  		rc = -ENODEV;
  		goto fail;
  	}
  
  	/* read GSCR */
  	rc = sata_pmp_read_gscr(dev, gscr);
  	if (rc)
  		goto fail;
  
  	/* is the pmp still there? */
  	if (!sata_pmp_same_pmp(dev, gscr)) {
  		rc = -ENODEV;
  		goto fail;
  	}
  
  	memcpy(dev->gscr, gscr, sizeof(gscr[0]) * SATA_PMP_GSCR_DWORDS);
  
  	rc = sata_pmp_configure(dev, 0);
  	if (rc)
  		goto fail;
  
  	ata_eh_done(link, NULL, ATA_EH_REVALIDATE);
  
  	DPRINTK("EXIT, rc=0
  ");
  	return 0;
  
   fail:

  	ata_dev_err(dev, "PMP revalidation failed (errno=%d)
  ", rc);

  	DPRINTK("EXIT, rc=%d
  ", rc);
  	return rc;
  }
  
  /**
   *	sata_pmp_revalidate_quick - revalidate SATA PMP quickly
   *	@dev: PMP device to revalidate
   *
   *	Make sure the attached PMP is accessible.
   *
   *	LOCKING:
   *	Kernel thread context (may sleep).
   *
   *	RETURNS:
   *	0 on success, -errno otherwise.
   */
  static int sata_pmp_revalidate_quick(struct ata_device *dev)
  {

  	unsigned int err_mask;

  	u32 prod_id;

  	err_mask = sata_pmp_read(dev->link, SATA_PMP_GSCR_PROD_ID, &prod_id);
  	if (err_mask) {

  		ata_dev_err(dev,
  			    "failed to read PMP product ID (Emask=0x%x)
  ",
  			    err_mask);

  		return -EIO;

  	}
  
  	if (prod_id != dev->gscr[SATA_PMP_GSCR_PROD_ID]) {

  		ata_dev_err(dev, "PMP product ID mismatch
  ");

  		/* something weird is going on, request full PMP recovery */
  		return -EIO;
  	}
  
  	return 0;
  }
  
  /**
   *	sata_pmp_eh_recover_pmp - recover PMP
   *	@ap: ATA port PMP is attached to
   *	@prereset: prereset method (can be NULL)
   *	@softreset: softreset method
   *	@hardreset: hardreset method
   *	@postreset: postreset method (can be NULL)
   *
   *	Recover PMP 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 PMP detachment.
   *
   *	LOCKING:
   *	Kernel thread context (may sleep).
   *
   *	RETURNS:
   *	0 on success, -errno on failure.
   */
  static int sata_pmp_eh_recover_pmp(struct ata_port *ap,
  		ata_prereset_fn_t prereset, ata_reset_fn_t softreset,
  		ata_reset_fn_t hardreset, ata_postreset_fn_t postreset)
  {
  	struct ata_link *link = &ap->link;
  	struct ata_eh_context *ehc = &link->eh_context;
  	struct ata_device *dev = link->device;
  	int tries = ATA_EH_PMP_TRIES;
  	int detach = 0, rc = 0;
  	int reval_failed = 0;
  
  	DPRINTK("ENTER
  ");
  
  	if (dev->flags & ATA_DFLAG_DETACH) {
  		detach = 1;

  		rc = -ENODEV;

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

  	if (ehc->i.action & ATA_EH_RESET) {

  		struct ata_link *tlink;

  		/* reset */

  		rc = ata_eh_reset(link, 0, prereset, softreset, hardreset,
  				  postreset);
  		if (rc) {

  			ata_link_err(link, "failed to reset PMP, giving up
  ");

  			goto fail;
  		}

  		/* PMP is reset, SErrors cannot be trusted, scan all */

  		ata_for_each_link(tlink, ap, EDGE) {

  			struct ata_eh_context *ehc = &tlink->eh_context;
  
  			ehc->i.probe_mask |= ATA_ALL_DEVICES;
  			ehc->i.action |= ATA_EH_RESET;
  		}

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

  			ehc->i.probe_mask |= ATA_ALL_DEVICES;

  			detach = 1;
  			/* give it just two more chances */
  			tries = min(tries, 2);
  		}
  
  		if (tries) {

  			/* consecutive revalidation failures? speed down */
  			if (reval_failed)

  				sata_down_spd_limit(link, 0);

  			else
  				reval_failed = 1;

  			ehc->i.action |= ATA_EH_RESET;

  			goto retry;
  		} else {

  			ata_dev_err(dev,
  				    "failed to recover PMP after %d tries, giving up
  ",
  				    ATA_EH_PMP_TRIES);

  			goto fail;
  		}
  	}
  
  	/* okay, PMP resurrected */
  	ehc->i.flags = 0;
  
  	DPRINTK("EXIT, rc=0
  ");
  	return 0;
  
   fail:
  	sata_pmp_detach(dev);
  	if (detach)
  		ata_eh_detach_dev(dev);
  	else
  		ata_dev_disable(dev);
  
  	DPRINTK("EXIT, rc=%d
  ", rc);
  	return rc;
  }
  
  static int sata_pmp_eh_handle_disabled_links(struct ata_port *ap)
  {
  	struct ata_link *link;
  	unsigned long flags;
  	int rc;
  
  	spin_lock_irqsave(ap->lock, flags);

  	ata_for_each_link(link, ap, EDGE) {

  		if (!(link->flags & ATA_LFLAG_DISABLED))
  			continue;
  
  		spin_unlock_irqrestore(ap->lock, flags);
  
  		/* Some PMPs require hardreset sequence to get
  		 * SError.N working.
  		 */

  		sata_link_hardreset(link, sata_deb_timing_normal,

  				ata_deadline(jiffies, ATA_TMOUT_INTERNAL_QUICK),
  				NULL, NULL);

  
  		/* unconditionally clear SError.N */
  		rc = sata_scr_write(link, SCR_ERROR, SERR_PHYRDY_CHG);
  		if (rc) {

  			ata_link_err(link,
  				     "failed to clear SError.N (errno=%d)
  ",
  				     rc);

  			return rc;
  		}
  
  		spin_lock_irqsave(ap->lock, flags);
  	}
  
  	spin_unlock_irqrestore(ap->lock, flags);
  
  	return 0;
  }
  
  static int sata_pmp_handle_link_fail(struct ata_link *link, int *link_tries)
  {
  	struct ata_port *ap = link->ap;
  	unsigned long flags;
  
  	if (link_tries[link->pmp] && --link_tries[link->pmp])
  		return 1;
  
  	/* disable this link */
  	if (!(link->flags & ATA_LFLAG_DISABLED)) {

  		ata_link_warn(link,

  			"failed to recover link after %d tries, disabling
  ",
  			ATA_EH_PMP_LINK_TRIES);
  
  		spin_lock_irqsave(ap->lock, flags);
  		link->flags |= ATA_LFLAG_DISABLED;
  		spin_unlock_irqrestore(ap->lock, flags);
  	}
  
  	ata_dev_disable(link->device);
  	link->eh_context.i.action = 0;
  
  	return 0;
  }
  
  /**
   *	sata_pmp_eh_recover - recover PMP-enabled port
   *	@ap: ATA port to recover

   *
   *	Drive EH recovery operation for PMP enabled port @ap.  This
   *	function recovers host and PMP ports with proper retrials and
   *	fallbacks.  Actual recovery operations are performed using
   *	ata_eh_recover() and sata_pmp_eh_recover_pmp().
   *
   *	LOCKING:
   *	Kernel thread context (may sleep).
   *
   *	RETURNS:
   *	0 on success, -errno on failure.
   */

  static int sata_pmp_eh_recover(struct ata_port *ap)

  {

  	struct ata_port_operations *ops = ap->ops;

  	int pmp_tries, link_tries[SATA_PMP_MAX_PORTS];
  	struct ata_link *pmp_link = &ap->link;
  	struct ata_device *pmp_dev = pmp_link->device;
  	struct ata_eh_context *pmp_ehc = &pmp_link->eh_context;

  	u32 *gscr = pmp_dev->gscr;

  	struct ata_link *link;
  	struct ata_device *dev;

  	unsigned int err_mask;

  	u32 gscr_error, sntf;
  	int cnt, rc;
  
  	pmp_tries = ATA_EH_PMP_TRIES;

  	ata_for_each_link(link, ap, EDGE)

  		link_tries[link->pmp] = ATA_EH_PMP_LINK_TRIES;
  
   retry:
  	/* PMP attached? */

  	if (!sata_pmp_attached(ap)) {

  		rc = ata_eh_recover(ap, ops->prereset, ops->softreset,
  				    ops->hardreset, ops->postreset, NULL);

  		if (rc) {

  			ata_for_each_dev(dev, &ap->link, ALL)

  				ata_dev_disable(dev);
  			return rc;
  		}
  
  		if (pmp_dev->class != ATA_DEV_PMP)
  			return 0;
  
  		/* new PMP online */

  		ata_for_each_link(link, ap, EDGE)

  			link_tries[link->pmp] = ATA_EH_PMP_LINK_TRIES;
  
  		/* fall through */
  	}
  
  	/* recover pmp */

  	rc = sata_pmp_eh_recover_pmp(ap, ops->prereset, ops->softreset,
  				     ops->hardreset, ops->postreset);

  	if (rc)
  		goto pmp_fail;

  	/* PHY event notification can disturb reset and other recovery
  	 * operations.  Turn it off.
  	 */
  	if (gscr[SATA_PMP_GSCR_FEAT_EN] & SATA_PMP_FEAT_NOTIFY) {
  		gscr[SATA_PMP_GSCR_FEAT_EN] &= ~SATA_PMP_FEAT_NOTIFY;
  
  		err_mask = sata_pmp_write(pmp_link, SATA_PMP_GSCR_FEAT_EN,
  					  gscr[SATA_PMP_GSCR_FEAT_EN]);
  		if (err_mask) {

  			ata_link_warn(pmp_link,

  				"failed to disable NOTIFY (err_mask=0x%x)
  ",
  				err_mask);
  			goto pmp_fail;
  		}
  	}

  	/* handle disabled links */
  	rc = sata_pmp_eh_handle_disabled_links(ap);
  	if (rc)
  		goto pmp_fail;
  
  	/* recover links */

  	rc = ata_eh_recover(ap, ops->pmp_prereset, ops->pmp_softreset,
  			    ops->pmp_hardreset, ops->pmp_postreset, &link);

  	if (rc)
  		goto link_fail;

  	/* clear SNotification */
  	rc = sata_scr_read(&ap->link, SCR_NOTIFICATION, &sntf);
  	if (rc == 0)
  		sata_scr_write(&ap->link, SCR_NOTIFICATION, sntf);

  	/*
  	 * If LPM is active on any fan-out port, hotplug wouldn't
  	 * work.  Return w/ PHY event notification disabled.
  	 */
  	ata_for_each_link(link, ap, EDGE)
  		if (link->lpm_policy > ATA_LPM_MAX_POWER)
  			return 0;
  
  	/*
  	 * Connection status might have changed while resetting other
  	 * links, enable notification and check SATA_PMP_GSCR_ERROR
  	 * before returning.
  	 */

  	/* enable notification */
  	if (pmp_dev->flags & ATA_DFLAG_AN) {

  		gscr[SATA_PMP_GSCR_FEAT_EN] |= SATA_PMP_FEAT_NOTIFY;

  		err_mask = sata_pmp_write(pmp_link, SATA_PMP_GSCR_FEAT_EN,
  					  gscr[SATA_PMP_GSCR_FEAT_EN]);

  		if (err_mask) {

  			ata_dev_err(pmp_dev,
  				    "failed to write PMP_FEAT_EN (Emask=0x%x)
  ",
  				    err_mask);

  			rc = -EIO;

  			goto pmp_fail;
  		}
  	}
  
  	/* check GSCR_ERROR */

  	err_mask = sata_pmp_read(pmp_link, SATA_PMP_GSCR_ERROR, &gscr_error);
  	if (err_mask) {

  		ata_dev_err(pmp_dev,
  			    "failed to read PMP_GSCR_ERROR (Emask=0x%x)
  ",
  			    err_mask);

  		rc = -EIO;

  		goto pmp_fail;
  	}
  
  	cnt = 0;

  	ata_for_each_link(link, ap, EDGE) {

  		if (!(gscr_error & (1 << link->pmp)))
  			continue;
  
  		if (sata_pmp_handle_link_fail(link, link_tries)) {
  			ata_ehi_hotplugged(&link->eh_context.i);
  			cnt++;
  		} else {

  			ata_link_warn(link,
  				"PHY status changed but maxed out on retries, giving up
  ");
  			ata_link_warn(link,
  				"Manually issue scan to resume this link
  ");

  		}
  	}
  
  	if (cnt) {

  		ata_port_info(ap,
  			"PMP SError.N set for some ports, repeating recovery
  ");

  		goto retry;
  	}
  
  	return 0;
  
   link_fail:
  	if (sata_pmp_handle_link_fail(link, link_tries)) {

  		pmp_ehc->i.action |= ATA_EH_RESET;

  		goto retry;
  	}
  
  	/* fall through */
   pmp_fail:
  	/* Control always ends up here after detaching PMP.  Shut up
  	 * and return if we're unloading.
  	 */
  	if (ap->pflags & ATA_PFLAG_UNLOADING)
  		return rc;

  	if (!sata_pmp_attached(ap))

  		goto retry;
  
  	if (--pmp_tries) {

  		pmp_ehc->i.action |= ATA_EH_RESET;

  		goto retry;
  	}

  	ata_port_err(ap, "failed to recover PMP after %d tries, giving up
  ",
  		     ATA_EH_PMP_TRIES);

  	sata_pmp_detach(pmp_dev);
  	ata_dev_disable(pmp_dev);
  
  	return rc;
  }
  
  /**

   *	sata_pmp_error_handler - do standard error handling for PMP-enabled host

   *	@ap: host port to handle error for

   *
   *	Perform standard error handling sequence for PMP-enabled host
   *	@ap.
   *
   *	LOCKING:
   *	Kernel thread context (may sleep).
   */

  void sata_pmp_error_handler(struct ata_port *ap)

  {
  	ata_eh_autopsy(ap);
  	ata_eh_report(ap);

  	sata_pmp_eh_recover(ap);

  	ata_eh_finish(ap);
  }

  
  EXPORT_SYMBOL_GPL(sata_pmp_port_ops);
  EXPORT_SYMBOL_GPL(sata_pmp_qc_defer_cmd_switch);
  EXPORT_SYMBOL_GPL(sata_pmp_error_handler);