path: root/drivers/ata/libahci.c

/*
 *  libahci.c - Common AHCI SATA low-level routines
 *
 *  Maintained by:  Jeff Garzik <jgarzik@pobox.com>
 *    		    Please ALWAYS copy linux-ide@vger.kernel.org
 *		    on emails.
 *
 *  Copyright 2004-2005 Red Hat, Inc.
 *
 *
 *  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.*
 *
 * AHCI hardware documentation:
 * http://www.intel.com/technology/serialata/pdf/rev1_0.pdf
 * http://www.intel.com/technology/serialata/pdf/rev1_1.pdf
 *
 */

#include <linux/kernel.h>
#include <linux/gfp.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/blkdev.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/dma-mapping.h>
#include <linux/device.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_cmnd.h>
#include <linux/libata.h>
#include "ahci.h"

static int ahci_skip_host_reset;
int ahci_ignore_sss;
EXPORT_SYMBOL_GPL(ahci_ignore_sss);

module_param_named(skip_host_reset, ahci_skip_host_reset, int, 0444);
MODULE_PARM_DESC(skip_host_reset, "skip global host reset (0=don't skip, 1=skip)");

module_param_named(ignore_sss, ahci_ignore_sss, int, 0444);
MODULE_PARM_DESC(ignore_sss, "Ignore staggered spinup flag (0=don't ignore, 1=ignore)");

static int ahci_enable_alpm(struct ata_port *ap,
		enum link_pm policy);
static void ahci_disable_alpm(struct ata_port *ap);
static ssize_t ahci_led_show(struct ata_port *ap, char *buf);
static ssize_t ahci_led_store(struct ata_port *ap, const char *buf,
			      size_t size);
static ssize_t ahci_transmit_led_message(struct ata_port *ap, u32 state,
					ssize_t size);



static int ahci_scr_read(struct ata_link *link, unsigned int sc_reg, u32 *val);
static int ahci_scr_write(struct ata_link *link, unsigned int sc_reg, u32 val);
static unsigned int ahci_qc_issue(struct ata_queued_cmd *qc);
static bool ahci_qc_fill_rtf(struct ata_queued_cmd *qc);
static int ahci_port_start(struct ata_port *ap);
static void ahci_port_stop(struct ata_port *ap);
static void ahci_qc_prep(struct ata_queued_cmd *qc);
static int ahci_pmp_qc_defer(struct ata_queued_cmd *qc);
static void ahci_freeze(struct ata_port *ap);
static void ahci_thaw(struct ata_port *ap);
static void ahci_enable_fbs(struct ata_port *ap);
static void ahci_disable_fbs(struct ata_port *ap);
static void ahci_pmp_attach(struct ata_port *ap);
static void ahci_pmp_detach(struct ata_port *ap);
static int ahci_softreset(struct ata_link *link, unsigned int *class,
			  unsigned long deadline);
static int ahci_hardreset(struct ata_link *link, unsigned int *class,
			  unsigned long deadline);
static void ahci_postreset(struct ata_link *link, unsigned int *class);
static void ahci_error_handler(struct ata_port *ap);
static void ahci_post_internal_cmd(struct ata_queued_cmd *qc);
static int ahci_port_resume(struct ata_port *ap);
static void ahci_dev_config(struct ata_device *dev);
static void ahci_fill_cmd_slot(struct ahci_port_priv *pp, unsigned int tag,
			       u32 opts);
#ifdef CONFIG_PM
static int ahci_port_suspend(struct ata_port *ap, pm_message_t mesg);
#endif
static ssize_t ahci_activity_show(struct ata_device *dev, char *buf);
static ssize_t ahci_activity_store(struct ata_device *dev,
				   enum sw_activity val);
static void ahci_init_sw_activity(struct ata_link *link);

static ssize_t ahci_show_host_caps(struct device *dev,
				   struct device_attribute *attr, char *buf);
static ssize_t ahci_show_host_cap2(struct device *dev,
				   struct device_attribute *attr, char *buf);
static ssize_t ahci_show_host_version(struct device *dev,
				      struct device_attribute *attr, char *buf);
static ssize_t ahci_show_port_cmd(struct device *dev,
				  struct device_attribute *attr, char *buf);

static DEVICE_ATTR(ahci_host_caps, S_IRUGO, ahci_show_host_caps, NULL);
static DEVICE_ATTR(ahci_host_cap2, S_IRUGO, ahci_show_host_cap2, NULL);
static DEVICE_ATTR(ahci_host_version, S_IRUGO, ahci_show_host_version, NULL);
static DEVICE_ATTR(ahci_port_cmd, S_IRUGO, ahci_show_port_cmd, NULL);

static struct device_attribute *ahci_shost_attrs[] = {
	&dev_attr_link_power_management_policy,
	&dev_attr_em_message_type,
	&dev_attr_em_message,
	&dev_attr_ahci_host_caps,
	&dev_attr_ahci_host_cap2,
	&dev_attr_ahci_host_version,
	&dev_attr_ahci_port_cmd,
	NULL
};

static struct device_attribute *ahci_sdev_attrs[] = {
	&dev_attr_sw_activity,
	&dev_attr_unload_heads,
	NULL
};

struct scsi_host_template ahci_sht = {
	ATA_NCQ_SHT("ahci"),
	.can_queue		= AHCI_MAX_CMDS - 1,
	.sg_tablesize		= AHCI_MAX_SG,
	.dma_boundary		= AHCI_DMA_BOUNDARY,
	.shost_attrs		= ahci_shost_attrs,
	.sdev_attrs		= ahci_sdev_attrs,
};
EXPORT_SYMBOL_GPL(ahci_sht);

struct ata_port_operations ahci_ops = {
	.inherits		= &sata_pmp_port_ops,

	.qc_defer		= ahci_pmp_qc_defer,
	.qc_prep		= ahci_qc_prep,
	.qc_issue		= ahci_qc_issue,
	.qc_fill_rtf		= ahci_qc_fill_rtf,

	.freeze			= ahci_freeze,
	.thaw			= ahci_thaw,
	.softreset		= ahci_softreset,
	.hardreset		= ahci_hardreset,
	.postreset		= ahci_postreset,
	.pmp_softreset		= ahci_softreset,
	.error_handler		= ahci_error_handler,
	.post_internal_cmd	= ahci_post_internal_cmd,
	.dev_config		= ahci_dev_config,

	.scr_read		= ahci_scr_read,
	.scr_write		= ahci_scr_write,
	.pmp_attach		= ahci_pmp_attach,
	.pmp_detach		= ahci_pmp_detach,

	.enable_pm		= ahci_enable_alpm,
	.disable_pm		= ahci_disable_alpm,
	.em_show		= ahci_led_show,
	.em_store		= ahci_led_store,
	.sw_activity_show	= ahci_activity_show,
	.sw_activity_store	= ahci_activity_store,
#ifdef CONFIG_PM
	.port_suspend		= ahci_port_suspend,
	.port_resume		= ahci_port_resume,
#endif
	.port_start		= ahci_port_start,
	.port_stop		= ahci_port_stop,
};
EXPORT_SYMBOL_GPL(ahci_ops);

int ahci_em_messages = 1;
EXPORT_SYMBOL_GPL(ahci_em_messages);
module_param(ahci_em_messages, int, 0444);
/* add other LED protocol types when they become supported */
MODULE_PARM_DESC(ahci_em_messages,
	"Set AHCI Enclosure Management Message type (0 = disabled, 1 = LED");

static void ahci_enable_ahci(void __iomem *mmio)
{
	int i;
	u32 tmp;

	/* turn on AHCI_EN */
	tmp = readl(mmio + HOST_CTL);
	if (tmp & HOST_AHCI_EN)
		return;

	/* Some controllers need AHCI_EN to be written multiple times.
	 * Try a few times before giving up.
	 */
	for (i = 0; i < 5; i++) {
		tmp |= HOST_AHCI_EN;
		writel(tmp, mmio + HOST_CTL);
		tmp = readl(mmio + HOST_CTL);	/* flush && sanity check */
		if (tmp & HOST_AHCI_EN)
			return;
		msleep(10);
	}

	WARN_ON(1);
}

static ssize_t ahci_show_host_caps(struct device *dev,
				   struct device_attribute *attr, char *buf)
{
	struct Scsi_Host *shost = class_to_shost(dev);
	struct ata_port *ap = ata_shost_to_port(shost);
	struct ahci_host_priv *hpriv = ap->host->private_data;

	return sprintf(buf, "%x\n", hpriv->cap);
}

static ssize_t ahci_show_host_cap2(struct device *dev,
				   struct device_attribute *attr, char *buf)
{
	struct Scsi_Host *shost = class_to_shost(dev);
	struct ata_port *ap = ata_shost_to_port(shost);
	struct ahci_host_priv *hpriv = ap->host->private_data;

	return sprintf(buf, "%x\n", hpriv->cap2);
}

static ssize_t ahci_show_host_version(struct device *dev,
				   struct device_attribute *attr, char *buf)
{
	struct Scsi_Host *shost = class_to_shost(dev);
	struct ata_port *ap = ata_shost_to_port(shost);
	struct ahci_host_priv *hpriv = ap->host->private_data;
	void __iomem *mmio = hpriv->mmio;

	return sprintf(buf, "%x\n", readl(mmio + HOST_VERSION));
}

static ssize_t ahci_show_port_cmd(struct device *dev,
				  struct device_attribute *attr, char *buf)
{
	struct Scsi_Host *shost = class_to_shost(dev);
	struct ata_port *ap = ata_shost_to_port(shost);
	void __iomem *port_mmio = ahci_port_base(ap);

	return sprintf(buf, "%x\n", readl(port_mmio + PORT_CMD));
}

/**
 *	ahci_save_initial_config - Save and fixup initial config values
 *	@dev: target AHCI device
 *	@hpriv: host private area to store config values
 *	@force_port_map: force port map to a specified value
 *	@mask_port_map: mask out particular bits from port map
 *
 *	Some registers containing configuration info might be setup by
 *	BIOS and might be cleared on reset.  This function saves the
 *	initial values of those registers into @hpriv such that they
 *	can be restored after controller reset.
 *
 *	If inconsistent, config values are fixed up by this function.
 *
 *	LOCKING:
 *	None.
 */
void ahci_save_initial_config(struct device *dev,
			      struct ahci_host_priv *hpriv,
			      unsigned int force_port_map,
			      unsigned int mask_port_map)
{
	void __iomem *mmio = hpriv->mmio;
	u32 cap, cap2, vers, port_map;
	int i;

	/* make sure AHCI mode is enabled before accessing CAP */
	ahci_enable_ahci(mmio);

	/* Values prefixed with saved_ are written back to host after
	 * reset.  Values without are used for driver operation.
	 */
	hpriv->saved_cap = cap = readl(mmio + HOST_CAP);
	hpriv->saved_port_map = port_map = readl(mmio + HOST_PORTS_IMPL);

	/* CAP2 register is only defined for AHCI 1.2 and later */
	vers = readl(mmio + HOST_VERSION);
	if ((vers >> 16) > 1 ||
	   ((vers >> 16) == 1 && (vers & 0xFFFF) >= 0x200))
		hpriv->saved_cap2 = cap2 = readl(mmio + HOST_CAP2);
	else
		hpriv->saved_cap2 = cap2 = 0;

	/* some chips have errata preventing 64bit use */
	if ((cap & HOST_CAP_64) && (hpriv->flags & AHCI_HFLAG_32BIT_ONLY)) {
		dev_printk(KERN_INFO, dev,
			   "controller can't do 64bit DMA, forcing 32bit\n");
		cap &= ~HOST_CAP_64;
	}

	if ((cap & HOST_CAP_NCQ) && (hpriv->flags & AHCI_HFLAG_NO_NCQ)) {
		dev_printk(KERN_INFO, dev,
			   "controller can't do NCQ, turning off CAP_NCQ\n");
		cap &= ~HOST_CAP_NCQ;
	}

	if (!(cap & HOST_CAP_NCQ) && (hpriv->flags & AHCI_HFLAG_YES_NCQ)) {
		dev_printk(KERN_INFO, dev,
			   "controller can do NCQ, turning on CAP_NCQ\n");
		cap |= HOST_CAP_NCQ;
	}

	if ((cap & HOST_CAP_PMP) && (hpriv->flags & AHCI_HFLAG_NO_PMP)) {
		dev_printk(KERN_INFO, dev,
			   "controller can't do PMP, turning off CAP_PMP\n");
		cap &= ~HOST_CAP_PMP;
	}

	if ((cap & HOST_CAP_SNTF) && (hpriv->flags & AHCI_HFLAG_NO_SNTF)) {
		dev_printk(KERN_INFO, dev,
			   "controller can't do SNTF, turning off CAP_SNTF\n");
		cap &= ~HOST_CAP_SNTF;
	}

	if (force_port_map && port_map != force_port_map) {
		dev_printk(KERN_INFO, dev, "forcing port_map 0x%x -> 0x%x\n",
			   port_map, force_port_map);
		port_map = force_port_map;
	}

	if (mask_port_map) {
		dev_printk(KERN_ERR, dev, "masking port_map 0x%x -> 0x%x\n",
			   port_map,
			   port_map & mask_port_map);
		port_map &= mask_port_map;
	}

	/* cross check port_map and cap.n_ports */
	if (port_map) {
		int map_ports = 0;

		for (i = 0; i < AHCI_MAX_PORTS; i++)
			if (port_map & (1 << i))
				map_ports++;

		/* If PI has more ports than n_ports, whine, clear
		 * port_map and let it be generated from n_ports.
		 */
		if (map_ports > ahci_nr_ports(cap)) {
			dev_printk(KERN_WARNING, dev,
				   "implemented port map (0x%x) contains more "
				   "ports than nr_ports (%u), using nr_ports\n",
				   port_map, ahci_nr_ports(cap));
			port_map = 0;
		}
	}

	/* fabricate port_map from cap.nr_ports */
	if (!port_map) {
		port_map = (1 << ahci_nr_ports(cap)) - 1;
		dev_printk(KERN_WARNING, dev,
			   "forcing PORTS_IMPL to 0x%x\n", port_map);

		/* write the fixed up value to the PI register */
		hpriv->saved_port_map = port_map;
	}

	/* record values to use during operation */
	hpriv->cap = cap;
	hpriv->cap2 = cap2;
	hpriv->port_map = port_map;
}
EXPORT_SYMBOL_GPL(ahci_save_initial_config);

/**
 *	ahci_restore_initial_config - Restore initial config
 *	@host: target ATA host
 *
 *	Restore initial config stored by ahci_save_initial_config().
 *
 *	LOCKING:
 *	None.
 */
static void ahci_restore_initial_config(struct ata_host *host)
{
	struct ahci_host_priv *hpriv = host->private_data;
	void __iomem *mmio = hpriv->mmio;

	writel(hpriv->saved_cap, mmio + HOST_CAP);
	if (hpriv->saved_cap2)
		writel(hpriv->saved_cap2, mmio + HOST_CAP2);
	writel(hpriv->saved_port_map, mmio + HOST_PORTS_IMPL);
	(void) readl(mmio + HOST_PORTS_IMPL);	/* flush */
}

static unsigned ahci_scr_offset(struct ata_port *ap, unsigned int sc_reg)
{
	static const int offset[] = {
		[SCR_STATUS]		= PORT_SCR_STAT,
		[SCR_CONTROL]		= PORT_SCR_CTL,
		[SCR_ERROR]		= PORT_SCR_ERR,
		[SCR_ACTIVE]		= PORT_SCR_ACT,
		[SCR_NOTIFICATION]	= PORT_SCR_NTF,
	};
	struct ahci_host_priv *hpriv = ap->host->private_data;

	if (sc_reg < ARRAY_SIZE(offset) &&
	    (sc_reg != SCR_NOTIFICATION || (hpriv->cap & HOST_CAP_SNTF)))
		return offset[sc_reg];
	return 0;
}

static int ahci_scr_read(struct ata_link *link, unsigned int sc_reg, u32 *val)
{
	void __iomem *port_mmio = ahci_port_base(link->ap);
	int offset = ahci_scr_offset(link->ap, sc_reg);

	if (offset) {
		*val = readl(port_mmio + offset);
		return 0;
	}
	return -EINVAL;
}

static int ahci_scr_write(struct ata_link *link, unsigned int sc_reg, u32 val)
{
	void __iomem *port_mmio = ahci_port_base(link->ap);
	int offset = ahci_scr_offset(link->ap, sc_reg);

	if (offset) {
		writel(val, port_mmio + offset);
		return 0;
	}
	return -EINVAL;
}

static int ahci_is_device_present(void __iomem *port_mmio)
{
	u8 status = readl(port_mmio + PORT_TFDATA) & 0xff;

	/* Make sure PxTFD.STS.BSY and PxTFD.STS.DRQ are 0 */
	if (status & (ATA_BUSY | ATA_DRQ))
		return 0;

	/* Make sure PxSSTS.DET is 3h */
	status = readl(port_mmio + PORT_SCR_STAT) & 0xf;
	if (status != 3)
		return 0;
	return 1;
}

void ahci_start_engine(struct ata_port *ap)
{
	void __iomem *port_mmio = ahci_port_base(ap);
	u32 tmp;

	if (!ahci_is_device_present(port_mmio))
		return;

	/* start DMA */
	tmp = readl(port_mmio + PORT_CMD);
	tmp |= PORT_CMD_START;
	writel(tmp, port_mmio + PORT_CMD);
	readl(port_mmio + PORT_CMD); /* flush */
}
EXPORT_SYMBOL_GPL(ahci_start_engine);

int ahci_stop_engine(struct ata_port *ap)
{
	void __iomem *port_mmio = ahci_port_base(ap);
	u32 tmp;

	tmp = readl(port_mmio + PORT_CMD);

	/* check if the HBA is idle */
	if ((tmp & (PORT_CMD_START | PORT_CMD_LIST_ON)) == 0)
		return 0;

	/* setting HBA to idle */
	tmp &= ~PORT_CMD_START;
	writel(tmp, port_mmio + PORT_CMD);

	/* wait for engine to stop. This could be as long as 500 msec */
	tmp = ata_wait_register(port_mmio + PORT_CMD,
				PORT_CMD_LIST_ON, PORT_CMD_LIST_ON, 1, 500);
	if (tmp & PORT_CMD_LIST_ON)
		return -EIO;

	return 0;
}
EXPORT_SYMBOL_GPL(ahci_stop_engine);

static void ahci_start_fis_rx(struct ata_port *ap)
{
	void __iomem *port_mmio = ahci_port_base(ap);
	struct ahci_host_priv *hpriv = ap->host->private_data;
	struct ahci_port_priv *pp = ap->private_data;
	u32 tmp;

	/* set FIS registers */
	if (hpriv->cap & HOST_CAP_64)
		writel((pp->cmd_slot_dma >> 16) >> 16,
		       port_mmio + PORT_LST_ADDR_HI);
	writel(pp->cmd_slot_dma & 0xffffffff, port_mmio + PORT_LST_ADDR);

	if (hpriv->cap & HOST_CAP_64)
		writel((pp->rx_fis_dma >> 16) >> 16,
		       port_mmio + PORT_FIS_ADDR_HI);
	writel(pp->rx_fis_dma & 0xffffffff, port_mmio + PORT_FIS_ADDR);

	/* enable FIS reception */
	tmp = readl(port_mmio + PORT_CMD);
	tmp |= PORT_CMD_FIS_RX;
	writel(tmp, port_mmio + PORT_CMD);

	/* flush */
	readl(port_mmio + PORT_CMD);
}

static int ahci_stop_fis_rx(struct ata_port *ap)
{
	void __iomem *port_mmio = ahci_port_base(ap);
	u32 tmp;

	/* disable FIS reception */
	tmp = readl(port_mmio + PORT_CMD);
	tmp &= ~PORT_CMD_FIS_RX;
	writel(tmp, port_mmio + PORT_CMD);

	/* wait for completion, spec says 500ms, give it 1000 */
	tmp = ata_wait_register(port_mmio + PORT_CMD, PORT_CMD_FIS_ON,
				PORT_CMD_FIS_ON, 10, 1000);
	if (tmp & PORT_CMD_FIS_ON)
		return -EBUSY;

	return 0;
}

static void ahci_power_up(struct ata_port *ap)
{
	struct ahci_host_priv *hpriv = ap->host->private_data;
	void __iomem *port_mmio = ahci_port_base(ap);
	u32 cmd;

	cmd = readl(port_mmio + PORT_CMD) & ~PORT_CMD_ICC_MASK;

	/* spin up device */
	if (hpriv->cap & HOST_CAP_SSS) {
		cmd |= PORT_CMD_SPIN_UP;
		writel(cmd, port_mmio + PORT_CMD);
	}

	/* wake up link */
	writel(cmd | PORT_CMD_ICC_ACTIVE, port_mmio + PORT_CMD);
}

static void ahci_disable_alpm(struct ata_port *ap)
{
	struct ahci_host_priv *hpriv = ap->host->private_data;
	void __iomem *port_mmio = ahci_port_base(ap);
	u32 cmd;
	struct ahci_port_priv *pp = ap->private_data;

	/* IPM bits should be disabled by libata-core */
	/* get the existing command bits */
	cmd = readl(port_mmio + PORT_CMD);

	/* disable ALPM and ASP */
	cmd &= ~PORT_CMD_ASP;
	cmd &= ~PORT_CMD_ALPE;

	/* force the interface back to active */
	cmd |= PORT_CMD_ICC_ACTIVE;

	/* write out new cmd value */
	writel(cmd, port_mmio + PORT_CMD);
	cmd = readl(port_mmio + PORT_CMD);

	/* wait 10ms to be sure we've come out of any low power state */
	msleep(10);

	/* clear out any PhyRdy stuff from interrupt status */
	writel(PORT_IRQ_PHYRDY, port_mmio + PORT_IRQ_STAT);

	/* go ahead and clean out PhyRdy Change from Serror too */
	ahci_scr_write(&ap->link, SCR_ERROR, ((1 << 16) | (1 << 18)));

	/*
	 * Clear flag to indicate that we should ignore all PhyRdy
	 * state changes
	 */
	hpriv->flags &= ~AHCI_HFLAG_NO_HOTPLUG;

	/*
	 * Enable interrupts on Phy Ready.
	 */
	pp->intr_mask |= PORT_IRQ_PHYRDY;
	writel(pp->intr_mask, port_mmio + PORT_IRQ_MASK);

	/*
	 * don't change the link pm policy - we can be called
	 * just to turn of link pm temporarily
	 */
}

static int ahci_enable_alpm(struct ata_port *ap,
	enum link_pm policy)
{
	struct ahci_host_priv *hpriv = ap->host->private_data;
	void __iomem *port_mmio = ahci_port_base(ap);
	u32 cmd;
	struct ahci_port_priv *pp = ap->private_data;
	u32 asp;

	/* Make sure the host is capable of link power management */
	if (!(hpriv->cap & HOST_CAP_ALPM))
		return -EINVAL;

	switch (policy) {
	case MAX_PERFORMANCE:
	case NOT_AVAILABLE:
		/*
		 * if we came here with NOT_AVAILABLE,
		 * it just means this is the first time we
		 * have tried to enable - default to max performance,
		 * and let the user go to lower power modes on request.
		 */
		ahci_disable_alpm(ap);
		return 0;
	case MIN_POWER:
		/* configure HBA to enter SLUMBER */
		asp = PORT_CMD_ASP;
		break;
	case MEDIUM_POWER:
		/* configure HBA to enter PARTIAL */
		asp = 0;
		break;
	default:
		return -EINVAL;
	}

	/*
	 * Disable interrupts on Phy Ready. This keeps us from
	 * getting woken up due to spurious phy ready interrupts
	 * TBD - Hot plug should be done via polling now, is
	 * that even supported?
	 */
	pp->intr_mask &= ~PORT_IRQ_PHYRDY;
	writel(pp->intr_mask, port_mmio + PORT_IRQ_MASK);

	/*
	 * Set a flag to indicate that we should ignore all PhyRdy
	 * state changes since these can happen now whenever we
	 * change link state
	 */
	hpriv->flags |= AHCI_HFLAG_NO_HOTPLUG;

	/* get the existing command bits */
	cmd = readl(port_mmio + PORT_CMD);

	/*
	 * Set ASP based on Policy
	 */
	cmd |= asp;

	/*
	 * Setting this bit will instruct the HBA to aggressively
	 * enter a lower power link state when it's appropriate and
	 * based on the value set above for ASP
	 */
	cmd |= PORT_CMD_ALPE;

	/* write out new cmd value */
	writel(cmd, port_mmio + PORT_CMD);
	cmd = readl(port_mmio + PORT_CMD);

	/* IPM bits should be set by libata-core */
	return 0;
}

#ifdef CONFIG_PM
static void ahci_power_down(struct ata_port *ap)
{
	struct ahci_host_priv *hpriv = ap->host->private_data;
	void __iomem *port_mmio = ahci_port_base(ap);
	u32 cmd, scontrol;

	if (!(hpriv->cap & HOST_CAP_SSS))
		return;

	/* put device into listen mode, first set PxSCTL.DET to 0 */
	scontrol = readl(port_mmio + PORT_SCR_CTL);
	scontrol &= ~0xf;
	writel(scontrol, port_mmio + PORT_SCR_CTL);

	/* then set PxCMD.SUD to 0 */
	cmd = readl(port_mmio + PORT_CMD) & ~PORT_CMD_ICC_MASK;
	cmd &= ~PORT_CMD_SPIN_UP;
	writel(cmd, port_mmio + PORT_CMD);
}
#endif

static void ahci_start_port(struct ata_port *ap)
{
	struct ahci_port_priv *pp = ap->private_data;
	struct ata_link *link;
	struct ahci_em_priv *emp;
	ssize_t rc;
	int i;

	/* enable FIS reception */
	ahci_start_fis_rx(ap);

	/* enable DMA */
	ahci_start_engine(ap);

	/* turn on LEDs */
	if (ap->flags & ATA_FLAG_EM) {
		ata_for_each_link(link, ap, EDGE) {
			emp = &pp->em_priv[link->pmp];

			/* EM Transmit bit maybe busy during init */
			for (i = 0; i < EM_MAX_RETRY; i++) {
				rc = ahci_transmit_led_message(ap,
							       emp->led_state,
							       4);
				if (rc == -EBUSY)
					msleep(1);
				else
					break;
			}
		}
	}

	if (ap->flags & ATA_FLAG_SW_ACTIVITY)
		ata_for_each_link(link, ap, EDGE)
			ahci_init_sw_activity(link);

}

static int ahci_deinit_port(struct ata_port *ap, const char **emsg)
{
	int rc;

	/* disable DMA */
	rc = ahci_stop_engine(ap);
	if (rc) {
		*emsg = "failed to stop engine";
		return rc;
	}

	/* disable FIS reception */
	rc = ahci_stop_fis_rx(ap);
	if (rc) {
		*emsg = "failed stop FIS RX";
		return rc;
	}

	return 0;
}

int ahci_reset_controller(struct ata_host *host)
{
	struct ahci_host_priv *hpriv = host->private_data;
	void __iomem *mmio = hpriv->mmio;
	u32 tmp;

	/* we must be in AHCI mode, before using anything
	 * AHCI-specific, such as HOST_RESET.
	 */
	ahci_enable_ahci(mmio);

	/* global controller reset */
	if (!ahci_skip_host_reset) {
		tmp = readl(mmio + HOST_CTL);
		if ((tmp & HOST_RESET) == 0) {
			writel(tmp | HOST_RESET, mmio + HOST_CTL);
			readl(mmio + HOST_CTL); /* flush */
		}

		/*
		 * to perform host reset, OS should set HOST_RESET
		 * and poll until this bit is read to be "0".
		 * reset must complete within 1 second, or
		 * the hardware should be considered fried.
		 */
		tmp = ata_wait_register(mmio + HOST_CTL, HOST_RESET,
					HOST_RESET, 10, 1000);

		if (tmp & HOST_RESET) {
			dev_printk(KERN_ERR, host->dev,
				   "controller reset failed (0x%x)\n", tmp);
			return -EIO;
		}

		/* turn on AHCI mode */
		ahci_enable_ahci(mmio);

		/* Some registers might be cleared on reset.  Restore
		 * initial values.
		 */
		ahci_restore_initial_config(host);
	} else
		dev_printk(KERN_INFO, host->dev,
			   "skipping global host reset\n");

	return 0;
}
EXPORT_SYMBOL_GPL(ahci_reset_controller);

static void ahci_sw_activity(struct ata_link *link)
{
	struct ata_port *ap = link->ap;
	struct ahci_port_priv *pp = ap->private_data;
	struct ahci_em_priv *emp = &pp->em_priv[link->pmp];

	if (!(link->flags & ATA_LFLAG_SW_ACTIVITY))
		return;

	emp->activity++;
	if (!timer_pending(&emp->timer))
		mod_timer(&emp->timer, jiffies + msecs_to_jiffies(10));
}

static void ahci_sw_activity_blink(unsigned long arg)
{
	struct ata_link *link = (struct ata_link *)arg;
	struct ata_port *ap = link->ap;
	struct ahci_port_priv *pp = ap->private_data;
	struct ahci_em_priv *emp = &pp->em_priv[link->pmp];
	unsigned long led_message = emp->led_state;
	u32 activity_led_state;
	unsigned long flags;

	led_message &= EM_MSG_LED_VALUE;
	led_message |= ap->port_no | (link->pmp << 8);

	/* check to see if we've had activity.  If so,
	 * toggle state of LED and reset timer.  If not,
	 * turn LED to desired idle state.
	 */
	spin_lock_irqsave(ap->lock, flags);
	if (emp->saved_activity != emp->activity) {
		emp->saved_activity = emp->activity;
		/* get the current LED state */
		activity_led_state = led_message & EM_MSG_LED_VALUE_ON;

		if (activity_led_state)
			activity_led_state = 0;
		else
			activity_led_state = 1;

		/* clear old state */
		led_message &= ~EM_MSG_LED_VALUE_ACTIVITY;

		/* toggle state */
		led_message |= (activity_led_state << 16);
		mod_timer(&emp->timer, jiffies + msecs_to_jiffies(100));
	} else {
		/* switch to idle */
		led_message &= ~EM_MSG_LED_VALUE_ACTIVITY;
		if (emp->blink_policy == BLINK_OFF)
			led_message |= (1 << 16);
	}
	spin_unlock_irqrestore(ap->lock, flags);
	ahci_transmit_led_message(ap, led_message, 4);
}

static void ahci_init_sw_activity(struct ata_link *link)
{
	struct ata_port *ap = link->ap;
	struct ahci_port_priv *pp = ap->private_data;
	struct ahci_em_priv *emp = &pp->em_priv[link->pmp];

	/* init activity stats, setup timer */
	emp->saved_activity = emp->activity = 0;
	setup_timer(&emp->timer, ahci_sw_activity_blink, (unsigned long)link);

	/* check our blink policy and set flag for link if it's enabled */
	if (emp->blink_policy)
		link->flags |= ATA_LFLAG_SW_ACTIVITY;
}

int ahci_reset_em(struct ata_host *host)
{
	struct ahci_host_priv *hpriv = host->private_data;
	void __iomem *mmio = hpriv->mmio;
	u32 em_ctl;

	em_ctl = readl(mmio + HOST_EM_CTL);
	if ((em_ctl & EM_CTL_TM) || (em_ctl & EM_CTL_RST))
		return -EINVAL;

	writel(em_ctl | EM_CTL_RST, mmio + HOST_EM_CTL);
	return 0;
}
EXPORT_SYMBOL_GPL(ahci_reset_em);

static ssize_t ahci_transmit_led_message(struct ata_port *ap, u32 state,
					ssize_t size)
{
	struct ahci_host_priv *hpriv = ap->host->private_data;
	struct ahci_port_priv *pp = ap->private_data;
	void __iomem *mmio = hpriv->mmio;
	u32 em_ctl;
	u32 message[] = {0, 0};
	unsigned long flags;
	int pmp;
	struct ahci_em_priv *emp;

	/* get the slot number from the message */
	pmp = (state & EM_MSG_LED_PMP_SLOT) >> 8;
	if (pmp < EM_MAX_SLOTS)
		emp = &pp->em_priv[pmp];
	else
		return -EINVAL;

	spin_lock_irqsave(ap->lock, flags);

	/*
	 * if we are still busy transmitting a previous message,
	 * do not allow
	 */
	em_ctl = readl(mmio + HOST_EM_CTL);
	if (em_ctl & EM_CTL_TM) {
		spin_unlock_irqrestore(ap->lock, flags);
		return -EBUSY;
	}

	/*
	 * create message header - this is all zero except for
	 * the message size, which is 4 bytes.
	 */
	message[0] |= (4 << 8);

	/* ignore 0:4 of byte zero, fill in port info yourself */
	message[1] = ((state & ~EM_MSG_LED_HBA_PORT) | ap->port_no);

	/* write message to EM_LOC */
	writel(message[0], mmio + hpriv->em_loc);
	writel(message[1], mmio + hpriv->em_loc+4);

	/* save off new led state for port/slot */
	emp->led_state = state;

	/*
	 * tell hardware to transmit the message
	 */
	writel(em_ctl | EM_CTL_TM, mmio + HOST_EM_CTL);

	spin_unlock_irqrestore(ap->lock, flags);
	return size;
}

static ssize_t ahci_led_show(struct ata_port *ap, char *buf)
{
	struct ahci_port_priv *pp = ap->private_data;
	struct ata_link *link;
	struct ahci_em_priv *emp;
	int rc = 0;

	ata_for_each_link(link, ap, EDGE) {
		emp = &pp->em_priv[link->pmp];
		rc += sprintf(buf, "%lx\n", emp->led_state);
	}
	return rc;
}

static ssize_t ahci_led_store(struct ata_port *ap, const char *buf,
				size_t size)
{
	int state;
	int pmp;
	struct ahci_port_priv *pp = ap->private_data;
	struct ahci_em_priv *emp;

	state = simple_strtoul(buf, NULL, 0);

	/* get the slot number from the message */
	pmp = (state & EM_MSG_LED_PMP_SLOT) >> 8;
	if (pmp < EM_MAX_SLOTS)
		emp = &pp->em_priv[pmp];
	else
		return -EINVAL;

	/* mask off the activity bits if we are in sw_activity
	 * mode, user should turn off sw_activity before setting
	 * activity led through em_message
	 */
	if (emp->blink_policy)
		state &= ~EM_MSG_LED_VALUE_ACTIVITY;

	return ahci_transmit_led_message(ap, state, size);
}

static ssize_t ahci_activity_store(struct ata_device *dev, enum sw_activity val)
{
	struct ata_link *link = dev->link;
	struct ata_port *ap = link->ap;
	struct ahci_port_priv *pp = ap->private_data;
	struct ahci_em_priv *emp = &pp->em_priv[link->pmp];
	u32 port_led_state = emp->led_state;

	/* save the desired Activity LED behavior */
	if (val == OFF) {
		/* clear LFLAG */
		link->flags &= ~(ATA_LFLAG_SW_ACTIVITY);

		/* set the LED to OFF */
		port_led_state &= EM_MSG_LED_VALUE_OFF;
		port_led_state |= (ap->port_no | (link->pmp << 8));
		ahci_transmit_led_message(ap, port_led_state, 4);
	} else {
		link->flags |= ATA_LFLAG_SW_ACTIVITY;
		if (val == BLINK_OFF) {
			/* set LED to ON for idle */
			port_led_state &= EM_MSG_LED_VALUE_OFF;
			port_led_state |= (ap->port_no | (link->pmp << 8));
			port_led_state |= EM_MSG_LED_VALUE_ON; /* check this */
			ahci_transmit_led_message(ap, port_led_state, 4);
		}
	}
	emp->blink_policy = val;
	return 0;
}

static ssize_t ahci_activity_show(struct ata_device *dev, char *buf)
{
	struct ata_link *link = dev->link;
	struct ata_port *ap = link->ap;
	struct ahci_port_priv *pp = ap->private_data;
	struct ahci_em_priv *emp = &pp->em_priv[link->pmp];

	/* display the saved value of activity behavior for this
	 * disk.
	 */
	return sprintf(buf, "%d\n", emp->blink_policy);
}

static void ahci_port_init(struct device *dev, struct ata_port *ap,
			   int port_no, void __iomem *mmio,
			   void __iomem *port_mmio)
{
	const char *emsg = NULL;
	int rc;
	u32 tmp;

	/* make sure port is not active */
	rc = ahci_deinit_port(ap, &emsg);
	if (rc)
		dev_warn(dev, "%s (%d)\n", emsg, rc);

	/* clear SError */
	tmp = readl(port_mmio + PORT_SCR_ERR);
	VPRINTK("PORT_SCR_ERR 0x%x\n", tmp);
	writel(tmp, port_mmio + PORT_SCR_ERR);

	/* clear port IRQ */
	tmp = readl(port_mmio + PORT_IRQ_STAT);
	VPRINTK("PORT_IRQ_STAT 0x%x\n", tmp);
	if (tmp)
		writel(tmp, port_mmio + PORT_IRQ_STAT);

	writel(1 << port_no, mmio + HOST_IRQ_STAT);
}

void ahci_init_controller(struct ata_host *host)
{
	struct ahci_host_priv *hpriv = host->private_data;
	void __iomem *mmio = hpriv->mmio;
	int i;
	void __iomem *port_mmio;
	u32 tmp;

	for (i = 0; i < host->n_ports; i++) {
		struct ata_port *ap = host->ports[i];

		port_mmio = ahci_port_base(ap);
		if (ata_port_is_dummy(ap))
			continue;

		ahci_port_init(host->dev, ap, i, mmio, port_mmio);
	}

	tmp = readl(mmio + HOST_CTL);
	VPRINTK("HOST_CTL 0x%x\n", tmp);
	writel(tmp | HOST_IRQ_EN, mmio + HOST_CTL);
	tmp = readl(mmio + HOST_CTL);
	VPRINTK("HOST_CTL 0x%x\n", tmp);
}
EXPORT_SYMBOL_GPL(ahci_init_controller);

static void ahci_dev_config(struct ata_device *dev)
{
	struct ahci_host_priv *hpriv = dev->link->ap->host->private_data;

	if (hpriv->flags & AHCI_HFLAG_SECT255) {
		dev->max_sectors = 255;
		ata_dev_printk(dev, KERN_INFO,
			       "SB600 AHCI: limiting to 255 sectors per cmd\n");
	}
}

static unsigned int ahci_dev_classify(struct ata_port *ap)
{
	void __iomem *port_mmio = ahci_port_base(ap);
	struct ata_taskfile tf;
	u32 tmp;

	tmp = readl(port_mmio + PORT_SIG);
	tf.lbah		= (tmp >> 24)	& 0xff;
	tf.lbam		= (tmp >> 16)	& 0xff;
	tf.lbal		= (tmp >> 8)	& 0xff;
	tf.nsect	= (tmp)		& 0xff;

	return ata_dev_classify(&tf);
}

static void ahci_fill_cmd_slot(struct ahci_port_priv *pp, unsigned int tag,
			       u32 opts)
{
	dma_addr_t cmd_tbl_dma;

	cmd_tbl_dma = pp->cmd_tbl_dma + tag * AHCI_CMD_TBL_SZ;

	pp->cmd_slot[tag].opts = cpu_to_le32(opts);
	pp->cmd_slot[tag].status = 0;
	pp->cmd_slot[tag].tbl_addr = cpu_to_le32(cmd_tbl_dma & 0xffffffff);
	pp->cmd_slot[tag].tbl_addr_hi = cpu_to_le32((cmd_tbl_dma >> 16) >> 16);
}

int ahci_kick_engine(struct ata_port *ap)
{
	void __iomem *port_mmio = ahci_port_base(ap);
	struct ahci_host_priv *hpriv = ap->host->private_data;
	u8 status = readl(port_mmio + PORT_TFDATA) & 0xFF;
	u32 tmp;
	int busy, rc;

	/* stop engine */
	rc = ahci_stop_engine(ap);
	if (rc)
		goto out_restart;

	/* need to do CLO?
	 * always do CLO if PMP is attached (AHCI-1.3 9.2)
	 */
	busy = status & (ATA_BUSY | ATA_DRQ);
	if (!busy && !sata_pmp_attached(ap)) {
		rc = 0;
		goto out_restart;
	}

	if (!(hpriv->cap & HOST_CAP_CLO)) {
		rc = -EOPNOTSUPP;
		goto out_restart;
	}

	/* perform CLO */
	tmp = readl(port_mmio + PORT_CMD);
	tmp |= PORT_CMD_CLO;
	writel(tmp, port_mmio + PORT_CMD);

	rc = 0;
	tmp = ata_wait_register(port_mmio + PORT_CMD,
				PORT_CMD_CLO, PORT_CMD_CLO, 1, 500);
	if (tmp & PORT_CMD_CLO)
		rc = -EIO;

	/* restart engine */
 out_restart:
	ahci_start_engine(ap);
	return rc;
}
EXPORT_SYMBOL_GPL(ahci_kick_engine);

static int ahci_exec_polled_cmd(struct ata_port *ap, int pmp,
				struct ata_taskfile *tf, int is_cmd, u16 flags,
				unsigned long timeout_msec)
{
	const u32 cmd_fis_len = 5; /* five dwords */
	struct ahci_port_priv *pp = ap->private_data;
	void __iomem *port_mmio = ahci_port_base(ap);
	u8 *fis = pp->cmd_tbl;
	u32 tmp;

	/* prep the command */
	ata_tf_to_fis(tf, pmp, is_cmd, fis);
	ahci_fill_cmd_slot(pp, 0, cmd_fis_len | flags | (pmp << 12));

	/* issue & wait */
	writel(1, port_mmio + PORT_CMD_ISSUE);

	if (timeout_msec) {
		tmp = ata_wait_register(port_mmio + PORT_CMD_ISSUE, 0x1, 0x1,
					1, timeout_msec);
		if (tmp & 0x1) {
			ahci_kick_engine(ap);
			return -EBUSY;
		}
	} else
		readl(port_mmio + PORT_CMD_ISSUE);	/* flush */

	return 0;
}

int ahci_do_softreset(struct ata_link *link, unsigned int *class,
		      int pmp, unsigned long deadline,
		      int (*check_ready)(struct ata_link *link))
{
	struct ata_port *ap = link->ap;
	struct ahci_host_priv *hpriv = ap->host->private_data;
	const char *reason = NULL;
	unsigned long now, msecs;
	struct ata_taskfile tf;
	int rc;

	DPRINTK("ENTER\n");

	/* prepare for SRST (AHCI-1.1 10.4.1) */
	rc = ahci_kick_engine(ap);
	if (rc && rc != -EOPNOTSUPP)
		ata_link_printk(link, KERN_WARNING,
				"failed to reset engine (errno=%d)\n", rc);

	ata_tf_init(link->device, &tf);

	/* issue the first D2H Register FIS */
	msecs = 0;
	now = jiffies;
	if (time_after(now, deadline))
		msecs = jiffies_to_msecs(deadline - now);

	tf.ctl |= ATA_SRST;
	if (ahci_exec_polled_cmd(ap, pmp, &tf, 0,
				 AHCI_CMD_RESET | AHCI_CMD_CLR_BUSY, msecs)) {
		rc = -EIO;
		reason = "1st FIS failed";
		goto fail;
	}

	/* spec says at least 5us, but be generous and sleep for 1ms */
	msleep(1);

	/* issue the second D2H Register FIS */
	tf.ctl &= ~ATA_SRST;
	ahci_exec_polled_cmd(ap, pmp, &tf, 0, 0, 0);

	/* wait for link to become ready */
	rc = ata_wait_after_reset(link, deadline, check_ready);
	if (rc == -EBUSY && hpriv->flags & AHCI_HFLAG_SRST_TOUT_IS_OFFLINE) {
		/*
		 * Workaround for cases where link online status can't
		 * be trusted.  Treat device readiness timeout as link
		 * offline.
		 */
		ata_link_printk(link, KERN_INFO,
				"device not ready, treating as offline\n");
		*class = ATA_DEV_NONE;
	} else if (rc) {
		/* link occupied, -ENODEV too is an error */
		reason = "device not ready";
		goto fail;
	} else
		*class = ahci_dev_classify(ap);

	DPRINTK("EXIT, class=%u\n", *class);
	return 0;

 fail:
	ata_link_printk(link, KERN_ERR, "softreset failed (%s)\n", reason);
	return rc;
}

int ahci_check_ready(struct ata_link *link)
{
	void __iomem *port_mmio = ahci_port_base(link->ap);
	u8 status = readl(port_mmio + PORT_TFDATA) & 0xFF;

	return ata_check_ready(status);
}
EXPORT_SYMBOL_GPL(ahci_check_ready);

static int ahci_softreset(struct ata_link *link, unsigned int *class,
			  unsigned long deadline)
{
	int pmp = sata_srst_pmp(link);

	DPRINTK("ENTER\n");

	return ahci_do_softreset(link, class, pmp, deadline, ahci_check_ready);
}
EXPORT_SYMBOL_GPL(ahci_do_softreset);

static int ahci_hardreset(struct ata_link *link, unsigned int *class,
			  unsigned long deadline)
{
	const unsigned long *timing = sata_ehc_deb_timing(&link->eh_context);
	struct ata_port *ap = link->ap;
	struct ahci_port_priv *pp = ap->private_data;
	u8 *d2h_fis = pp->rx_fis + RX_FIS_D2H_REG;
	struct ata_taskfile tf;
	bool online;
	int rc;

	DPRINTK("ENTER\n");

	ahci_stop_engine(ap);

	/* clear D2H reception area to properly wait for D2H FIS */
	ata_tf_init(link->device, &tf);
	tf.command = 0x80;
	ata_tf_to_fis(&tf, 0, 0, d2h_fis);

	rc = sata_link_hardreset(link, timing, deadline, &online,
				 ahci_check_ready);

	ahci_start_engine(ap);

	if (online)
		*class = ahci_dev_classify(ap);

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

static void ahci_postreset(struct ata_link *link, unsigned int *class)
{
	struct ata_port *ap = link->ap;
	void __iomem *port_mmio = ahci_port_base(ap);
	u32 new_tmp, tmp;

	ata_std_postreset(link, class);

	/* Make sure port's ATAPI bit is set appropriately */
	new_tmp = tmp = readl(port_mmio + PORT_CMD);
	if (*class == ATA_DEV_ATAPI)
		new_tmp |= PORT_CMD_ATAPI;
	else
		new_tmp &= ~PORT_CMD_ATAPI;
	if (new_tmp != tmp) {
		writel(new_tmp, port_mmio + PORT_CMD);
		readl(port_mmio + PORT_CMD); /* flush */
	}
}

static unsigned int ahci_fill_sg(struct ata_queued_cmd *qc, void *cmd_tbl)
{
	struct scatterlist *sg;
	struct ahci_sg *ahci_sg = cmd_tbl + AHCI_CMD_TBL_HDR_SZ;
	unsigned int si;

	VPRINTK("ENTER\n");

	/*
	 * Next, the S/G list.
	 */
	for_each_sg(qc->sg, sg, qc->n_elem, si) {
		dma_addr_t addr = sg_dma_address(sg);
		u32 sg_len = sg_dma_len(sg);

		ahci_sg[si].addr = cpu_to_le32(addr & 0xffffffff);
		ahci_sg[si].addr_hi = cpu_to_le32((addr >> 16) >> 16);
		ahci_sg[si].flags_size = cpu_to_le32(sg_len - 1);
	}

	return si;
}

static int ahci_pmp_qc_defer(struct ata_queued_cmd *qc)
{
	struct ata_port *ap = qc->ap;
	struct ahci_port_priv *pp = ap->private_data;

	if (!sata_pmp_attached(ap) || pp->fbs_enabled)
		return ata_std_qc_defer(qc);
	else
		return sata_pmp_qc_defer_cmd_switch(qc);
}

static void ahci_qc_prep(struct ata_queued_cmd *qc)
{
	struct ata_port *ap = qc->ap;
	struct ahci_port_priv *pp = ap->private_data;
	int is_atapi = ata_is_atapi(qc->tf.protocol);
	void *cmd_tbl;
	u32 opts;
	const u32 cmd_fis_len = 5; /* five dwords */
	unsigned int n_elem;

	/*
	 * Fill in command table information.  First, the header,
	 * a SATA Register - Host to Device command FIS.
	 */
	cmd_tbl = pp->cmd_tbl + qc->tag * AHCI_CMD_TBL_SZ;

	ata_tf_to_fis(&qc->tf, qc->dev->link->pmp, 1, cmd_tbl);
	if (is_atapi) {
		memset(cmd_tbl + AHCI_CMD_TBL_CDB, 0, 32);
		memcpy(cmd_tbl + AHCI_CMD_TBL_CDB, qc->cdb, qc->dev->cdb_len);
	}

	n_elem = 0;
	if (qc->flags & ATA_QCFLAG_DMAMAP)
		n_elem = ahci_fill_sg(qc, cmd_tbl);

	/*
	 * Fill in command slot information.
	 */
	opts = cmd_fis_len | n_elem << 16 | (qc->dev->link->pmp << 12);
	if (qc->tf.flags & ATA_TFLAG_WRITE)
		opts |= AHCI_CMD_WRITE;
	if (is_atapi)
		opts |= AHCI_CMD_ATAPI | AHCI_CMD_PREFETCH;

	ahci_fill_cmd_slot(pp, qc->tag, opts);
}

static void ahci_fbs_dec_intr(struct ata_port *ap)
{
	struct ahci_port_priv *pp = ap->private_data;
	void __iomem *port_mmio = ahci_port_base(ap);
	u32 fbs = readl(port_mmio + PORT_FBS);
	int retries = 3;

	DPRINTK("ENTER\n");
	BUG_ON(!pp->fbs_enabled);

	/* time to wait for DEC is not specified by AHCI spec,
	 * add a retry loop for safety.
	 */
	writel(fbs | PORT_FBS_DEC, port_mmio + PORT_FBS);
	fbs = readl(port_mmio + PORT_FBS);
	while ((fbs & PORT_FBS_DEC) && retries--) {
		udelay(1);
		fbs = readl(port_mmio + PORT_FBS);
	}

	if (fbs & PORT_FBS_DEC)
		dev_printk(KERN_ERR, ap->host->dev,
			   "failed to clear device error\n");
}

static void ahci_error_intr(struct ata_port *ap, u32 irq_stat)
{
	struct ahci_host_priv *hpriv = ap->host->private_data;
	struct ahci_port_priv *pp = ap->private_data;
	struct ata_eh_info *host_ehi = &ap->link.eh_info;
	struct ata_link *link = NULL;
	struct ata_queued_cmd *active_qc;
	struct ata_eh_info *active_ehi;
	bool fbs_need_dec = false;
	u32 serror;

	/* determine active link with error */
	if (pp->fbs_enabled) {
		void __iomem *port_mmio = ahci_port_base(ap);
		u32 fbs = readl(port_mmio + PORT_FBS);
		int pmp = fbs >> PORT_FBS_DWE_OFFSET;

		if ((fbs & PORT_FBS_SDE) && (pmp < ap->nr_pmp_links) &&
		    ata_link_online(&ap->pmp_link[pmp])) {
			link = &ap->pmp_link[pmp];
			fbs_need_dec = true;
		}

	} else
		ata_for_each_link(link, ap, EDGE)
			if (ata_link_active(link))
				break;

	if (!link)
		link = &ap->link;

	active_qc = ata_qc_from_tag(ap, link->active_tag);
	active_ehi = &link->eh_info;

	/* record irq stat */
	ata_ehi_clear_desc(host_ehi);
	ata_ehi_push_desc(host_ehi, "irq_stat 0x%08x", irq_stat);

	/* AHCI needs SError cleared; otherwise, it might lock up */
	ahci_scr_read(&ap->link, SCR_ERROR, &serror);
	ahci_scr_write(&ap->link, SCR_ERROR, serror);
	host_ehi->serror |= serror;

	/* some controllers set IRQ_IF_ERR on device errors, ignore it */
	if (hpriv->flags & AHCI_HFLAG_IGN_IRQ_IF_ERR)
		irq_stat &= ~PORT_IRQ_IF_ERR;

	if (irq_stat & PORT_IRQ_TF_ERR) {
		/* If qc is active, charge it; otherwise, the active
		 * link.  There's no active qc on NCQ errors.  It will
		 * be determined by EH by reading log page 10h.
		 */
		if (active_qc)
			active_qc->err_mask |= AC_ERR_DEV;
		else
			active_ehi->err_mask |= AC_ERR_DEV;

		if (hpriv->flags & AHCI_HFLAG_IGN_SERR_INTERNAL)
			host_ehi->serror &= ~SERR_INTERNAL;
	}

	if (irq_stat & PORT_IRQ_UNK_FIS) {
		u32 *unk = (u32 *)(pp->rx_fis + RX_FIS_UNK);

		active_ehi->err_mask |= AC_ERR_HSM;
		active_ehi->action |= ATA_EH_RESET;
		ata_ehi_push_desc(active_ehi,
				  "unknown FIS %08x %08x %08x %08x" ,
				  unk[0], unk[1], unk[2], unk[3]);
	}

	if (sata_pmp_attached(ap) && (irq_stat & PORT_IRQ_BAD_PMP)) {
		active_ehi->err_mask |= AC_ERR_HSM;
		active_ehi->action |= ATA_EH_RESET;
		ata_ehi_push_desc(active_ehi, "incorrect PMP");
	}

	if (irq_stat & (PORT_IRQ_HBUS_ERR | PORT_IRQ_HBUS_DATA_ERR)) {
		host_ehi->err_mask |= AC_ERR_HOST_BUS;
		host_ehi->action |= ATA_EH_RESET;
		ata_ehi_push_desc(host_ehi, "host bus error");
	}

	if (irq_stat & PORT_IRQ_IF_ERR) {
		if (fbs_need_dec)
			active_ehi->err_mask |= AC_ERR_DEV;
		else {
			host_ehi->err_mask |= AC_ERR_ATA_BUS;
			host_ehi->action |= ATA_EH_RESET;
		}

		ata_ehi_push_desc(host_ehi, "interface fatal error");
	}

	if (irq_stat & (PORT_IRQ_CONNECT | PORT_IRQ_PHYRDY)) {
		ata_ehi_hotplugged(host_ehi);
		ata_ehi_push_desc(host_ehi, "%s",
			irq_stat & PORT_IRQ_CONNECT ?
			"connection status changed" : "PHY RDY changed");
	}

	/* okay, let's hand over to EH */

	if (irq_stat & PORT_IRQ_FREEZE)
		ata_port_freeze(ap);
	else if (fbs_need_dec) {
		ata_link_abort(link);
		ahci_fbs_dec_intr(ap);
	} else
		ata_port_abort(ap);
}

static void ahci_port_intr(struct ata_port *ap)
{
	void __iomem *port_mmio = ahci_port_base(ap);
	struct ata_eh_info *ehi = &ap->link.eh_info;
	struct ahci_port_priv *pp = ap->private_data;
	struct ahci_host_priv *hpriv = ap->host->private_data;
	int resetting = !!(ap->pflags & ATA_PFLAG_RESETTING);
	u32 status, qc_active = 0;
	int rc;

	status = readl(port_mmio + PORT_IRQ_STAT);
	writel(status, port_mmio + PORT_IRQ_STAT);

	/* ignore BAD_PMP while resetting */
	if (unlikely(resetting))
		status &= ~PORT_IRQ_BAD_PMP;

	/* If we are getting PhyRdy, this is
	 * just a power state change, we should
	 * clear out this, plus the PhyRdy/Comm
	 * Wake bits from Serror
	 */
	if ((hpriv->flags & AHCI_HFLAG_NO_HOTPLUG) &&
		(status & PORT_IRQ_PHYRDY)) {
		status &= ~PORT_IRQ_PHYRDY;
		ahci_scr_write(&ap->link, SCR_ERROR, ((1 << 16) | (1 << 18)));
	}

	if (unlikely(status & PORT_IRQ_ERROR)) {
		ahci_error_intr(ap, status);
		return;
	}

	if (status & PORT_IRQ_SDB_FIS) {
		/* If SNotification is available, leave notification
		 * handling to sata_async_notification().  If not,
		 * emulate it by snooping SDB FIS RX area.
		 *
		 * Snooping FIS RX area is probably cheaper than
		 * poking SNotification but some constrollers which
		 * implement SNotification, ICH9 for example, don't
		 * store AN SDB FIS into receive area.
		 */
		if (hpriv->cap & HOST_CAP_SNTF)
			sata_async_notification(ap);
		else {
			/* If the 'N' bit in word 0 of the FIS is set,
			 * we just received asynchronous notification.
			 * Tell libata about it.
			 *
			 * Lack of SNotification should not appear in
			 * ahci 1.2, so the workaround is unnecessary
			 * when FBS is enabled.
			 */
			if (pp->fbs_enabled)
				WARN_ON_ONCE(1);
			else {
				const __le32 *f = pp->rx_fis + RX_FIS_SDB;
				u32 f0 = le32_to_cpu(f[0]);
				if (f0 & (1 << 15))
					sata_async_notification(ap);
			}
		}
	}

	/* pp->active_link is not reliable once FBS is enabled, both
	 * PORT_SCR_ACT and PORT_CMD_ISSUE should be checked because
	 * NCQ and non-NCQ commands may be in flight at the same time.
	 */
	if (pp->fbs_enabled) {
		if (ap->qc_active) {
			qc_active = readl(port_mmio + PORT_SCR_ACT);
			qc_active |= readl(port_mmio + PORT_CMD_ISSUE);
		}
	} else {
		/* pp->active_link is valid iff any command is in flight */
		if (ap->qc_active && pp->active_link->sactive)
			qc_active = readl(port_mmio + PORT_SCR_ACT);
		else
			qc_active = readl(port_mmio + PORT_CMD_ISSUE);
	}


	rc = ata_qc_complete_multiple(ap, qc_active);

	/* while resetting, invalid completions are expected */
	if (unlikely(rc < 0 && !resetting)) {
		ehi->err_mask |= AC_ERR_HSM;
		ehi->action |= ATA_EH_RESET;
		ata_port_freeze(ap);
	}
}

irqreturn_t ahci_interrupt(int irq, void *dev_instance)
{
	struct ata_host *host = dev_instance;
	struct ahci_host_priv *hpriv;
	unsigned int i, handled = 0;
	void __iomem *mmio;
	u32 irq_stat, irq_masked;

	VPRINTK("ENTER\n");

	hpriv = host->private_data;
	mmio = hpriv->mmio;

	/* sigh.  0xffffffff is a valid return from h/w */
	irq_stat = readl(mmio + HOST_IRQ_STAT);
	if (!irq_stat)
		return IRQ_NONE;

	irq_masked = irq_stat & hpriv->port_map;

	spin_lock(&host->lock);

	for (i = 0; i < host->n_ports; i++) {
		struct ata_port *ap;

		if (!(irq_masked & (1 << i)))
			continue;

		ap = host->ports[i];
		if (ap) {
			ahci_port_intr(ap);
			VPRINTK("port %u\n", i);
		} else {
			VPRINTK("port %u (no irq)\n", i);
			if (ata_ratelimit())
				dev_printk(KERN_WARNING, host->dev,
					"interrupt on disabled port %u\n", i);
		}

		handled = 1;
	}

	/* HOST_IRQ_STAT behaves as level triggered latch meaning that
	 * it should be cleared after all the port events are cleared;
	 * otherwise, it will raise a spurious interrupt after each
	 * valid one.  Please read section 10.6.2 of ahci 1.1 for more
	 * information.
	 *
	 * Also, use the unmasked value to clear interrupt as spurious
	 * pending event on a dummy port might cause screaming IRQ.
	 */
	writel(irq_stat, mmio + HOST_IRQ_STAT);

	spin_unlock(&host->lock);

	VPRINTK("EXIT\n");

	return IRQ_RETVAL(handled);
}
EXPORT_SYMBOL_GPL(ahci_interrupt);

static unsigned int ahci_qc_issue(struct ata_queued_cmd *qc)
{
	struct ata_port *ap = qc->ap;
	void __iomem *port_mmio = ahci_port_base(ap);
	struct ahci_port_priv *pp = ap->private_data;

	/* Keep track of the currently active link.  It will be used
	 * in completion path to determine whether NCQ phase is in
	 * progress.
	 */
	pp->active_link = qc->dev->link;

	if (qc->tf.protocol == ATA_PROT_NCQ)
		writel(1 << qc->tag, port_mmio + PORT_SCR_ACT);

	if (pp->fbs_enabled && pp->fbs_last_dev != qc->dev->link->pmp) {
		u32 fbs = readl(port_mmio + PORT_FBS);
		fbs &= ~(PORT_FBS_DEV_MASK | PORT_FBS_DEC);
		fbs |= qc->dev->link->pmp << PORT_FBS_DEV_OFFSET;
		writel(fbs, port_mmio + PORT_FBS);
		pp->fbs_last_dev = qc->dev->link->pmp;
	}

	writel(1 << qc->tag, port_mmio + PORT_CMD_ISSUE);

	ahci_sw_activity(qc->dev->link);

	return 0;
}

static bool ahci_qc_fill_rtf(struct ata_queued_cmd *qc)
{
	struct ahci_port_priv *pp = qc->ap->private_data;
	u8 *d2h_fis = pp->rx_fis + RX_FIS_D2H_REG;

	if (pp->fbs_enabled)
		d2h_fis += qc->dev->link->pmp * AHCI_RX_FIS_SZ;

	ata_tf_from_fis(d2h_fis, &qc->result_tf);
	return true;
}

static void ahci_freeze(struct ata_port *ap)
{
	void __iomem *port_mmio = ahci_port_base(ap);

	/* turn IRQ off */
	writel(0, port_mmio + PORT_IRQ_MASK);
}

static void ahci_thaw(struct ata_port *ap)
{
	struct ahci_host_priv *hpriv = ap->host->private_data;
	void __iomem *mmio = hpriv->mmio;
	void __iomem *port_mmio = ahci_port_base(ap);
	u32 tmp;
	struct ahci_port_priv *pp = ap->private_data;

	/* clear IRQ */
	tmp = readl(port_mmio + PORT_IRQ_STAT);
	writel(tmp, port_mmio + PORT_IRQ_STAT);
	writel(1 << ap->port_no, mmio + HOST_IRQ_STAT);

	/* turn IRQ back on */
	writel(pp->intr_mask, port_mmio + PORT_IRQ_MASK);
}

static void ahci_error_handler(struct ata_port *ap)
{
	if (!(ap->pflags & ATA_PFLAG_FROZEN)) {
		/* restart engine */
		ahci_stop_engine(ap);
		ahci_start_engine(ap);
	}

	sata_pmp_error_handler(ap);
}

static void ahci_post_internal_cmd(struct ata_queued_cmd *qc)
{
	struct ata_port *ap = qc->ap;

	/* make DMA engine forget about the failed command */
	if (qc->flags & ATA_QCFLAG_FAILED)
		ahci_kick_engine(ap);
}

static void ahci_enable_fbs(struct ata_port *ap)
{
	struct ahci_port_priv *pp = ap->private_data;
	void __iomem *port_mmio = ahci_port_base(ap);
	u32 fbs;
	int rc;

	if (!pp->fbs_supported)
		return;

	fbs = readl(port_mmio + PORT_FBS);
	if (fbs & PORT_FBS_EN) {
		pp->fbs_enabled = true;
		pp->fbs_last_dev = -1; /* initialization */
		return;
	}

	rc = ahci_stop_engine(ap);
	if (rc)
		return;

	writel(fbs | PORT_FBS_EN, port_mmio + PORT_FBS);
	fbs = readl(port_mmio + PORT_FBS);
	if (fbs & PORT_FBS_EN) {
		dev_printk(KERN_INFO, ap->host->dev, "FBS is enabled.\n");
		pp->fbs_enabled = true;
		pp->fbs_last_dev = -1; /* initialization */
	} else
		dev_printk(KERN_ERR, ap->host->dev, "Failed to enable FBS\n");

	ahci_start_engine(ap);
}

static void ahci_disable_fbs(struct ata_port *ap)
{
	struct ahci_port_priv *pp = ap->private_data;
	void __iomem *port_mmio = ahci_port_base(ap);
	u32 fbs;
	int rc;

	if (!pp->fbs_supported)
		return;

	fbs = readl(port_mmio + PORT_FBS);
	if ((fbs & PORT_FBS_EN) == 0) {
		pp->fbs_enabled = false;
		return;
	}

	rc = ahci_stop_engine(ap);
	if (rc)
		return;

	writel(fbs & ~PORT_FBS_EN, port_mmio + PORT_FBS);
	fbs = readl(port_mmio + PORT_FBS);
	if (fbs & PORT_FBS_EN)
		dev_printk(KERN_ERR, ap->host->dev, "Failed to disable FBS\n");
	else {
		dev_printk(KERN_INFO, ap->host->dev, "FBS is disabled.\n");
		pp->fbs_enabled = false;
	}

	ahci_start_engine(ap);
}

static void ahci_pmp_attach(struct ata_port *ap)
{
	void __iomem *port_mmio = ahci_port_base(ap);
	struct ahci_port_priv *pp = ap->private_data;
	u32 cmd;

	cmd = readl(port_mmio + PORT_CMD);
	cmd |= PORT_CMD_PMP;
	writel(cmd, port_mmio + PORT_CMD);

	ahci_enable_fbs(ap);

	pp->intr_mask |= PORT_IRQ_BAD_PMP;
	writel(pp->intr_mask, port_mmio + PORT_IRQ_MASK);
}

static void ahci_pmp_detach(struct ata_port *ap)
{
	void __iomem *port_mmio = ahci_port_base(ap);
	struct ahci_port_priv *pp = ap->private_data;
	u32 cmd;

	ahci_disable_fbs(ap);

	cmd = readl(port_mmio + PORT_CMD);
	cmd &= ~PORT_CMD_PMP;
	writel(cmd, port_mmio + PORT_CMD);

	pp->intr_mask &= ~PORT_IRQ_BAD_PMP;
	writel(pp->intr_mask, port_mmio + PORT_IRQ_MASK);
}

static int ahci_port_resume(struct ata_port *ap)
{
	ahci_power_up(ap);
	ahci_start_port(ap);

	if (sata_pmp_attached(ap))
		ahci_pmp_attach(ap);
	else
		ahci_pmp_detach(ap);

	return 0;
}

#ifdef CONFIG_PM
static int ahci_port_suspend(struct ata_port *ap, pm_message_t mesg)
{
	const char *emsg = NULL;
	int rc;

	rc = ahci_deinit_port(ap, &emsg);
	if (rc == 0)
		ahci_power_down(ap);
	else {
		ata_port_printk(ap, KERN_ERR, "%s (%d)\n", emsg, rc);
		ahci_start_port(ap);
	}

	return rc;
}
#endif

static int ahci_port_start(struct ata_port *ap)
{
	struct ahci_host_priv *hpriv = ap->host->private_data;
	struct device *dev = ap->host->dev;
	struct ahci_port_priv *pp;
	void *mem;
	dma_addr_t mem_dma;
	size_t dma_sz, rx_fis_sz;

	pp = devm_kzalloc(dev, sizeof(*pp), GFP_KERNEL);
	if (!pp)
		return -ENOMEM;

	/* check FBS capability */
	if ((hpriv->cap & HOST_CAP_FBS) && sata_pmp_supported(ap)) {
		void __iomem *port_mmio = ahci_port_base(ap);
		u32 cmd = readl(port_mmio + PORT_CMD);
		if (cmd & PORT_CMD_FBSCP)
			pp->fbs_supported = true;
		else
			dev_printk(KERN_WARNING, dev,
				   "The port is not capable of FBS\n");
	}

	if (pp->fbs_supported) {
		dma_sz = AHCI_PORT_PRIV_FBS_DMA_SZ;
		rx_fis_sz = AHCI_RX_FIS_SZ * 16;
	} else {
		dma_sz = AHCI_PORT_PRIV_DMA_SZ;
		rx_fis_sz = AHCI_RX_FIS_SZ;
	}

	mem = dmam_alloc_coherent(dev, dma_sz, &mem_dma, GFP_KERNEL);
	if (!mem)
		return -ENOMEM;
	memset(mem, 0, dma_sz);

	/*
	 * First item in chunk of DMA memory: 32-slot command table,
	 * 32 bytes each in size
	 */
	pp->cmd_slot = mem;
	pp->cmd_slot_dma = mem_dma;

	mem += AHCI_CMD_SLOT_SZ;
	mem_dma += AHCI_CMD_SLOT_SZ;

	/*
	 * Second item: Received-FIS area
	 */
	pp->rx_fis = mem;
	pp->rx_fis_dma = mem_dma;

	mem += rx_fis_sz;
	mem_dma += rx_fis_sz;

	/*
	 * Third item: data area for storing a single command
	 * and its scatter-gather table
	 */
	pp->cmd_tbl = mem;
	pp->cmd_tbl_dma = mem_dma;

	/*
	 * Save off initial list of interrupts to be enabled.
	 * This could be changed later
	 */
	pp->intr_mask = DEF_PORT_IRQ;

	ap->private_data = pp;

	/* engage engines, captain */
	return ahci_port_resume(ap);
}

static void ahci_port_stop(struct ata_port *ap)
{
	const char *emsg = NULL;
	int rc;

	/* de-initialize port */
	rc = ahci_deinit_port(ap, &emsg);
	if (rc)
		ata_port_printk(ap, KERN_WARNING, "%s (%d)\n", emsg, rc);
}

void ahci_print_info(struct ata_host *host, const char *scc_s)
{
	struct ahci_host_priv *hpriv = host->private_data;
	void __iomem *mmio = hpriv->mmio;
	u32 vers, cap, cap2, impl, speed;
	const char *speed_s;

	vers = readl(mmio + HOST_VERSION);
	cap = hpriv->cap;
	cap2 = hpriv->cap2;
	impl = hpriv->port_map;

	speed = (cap >> 20) & 0xf;
	if (speed == 1)
		speed_s = "1.5";
	else if (speed == 2)
		speed_s = "3";
	else if (speed == 3)
		speed_s = "6";
	else
		speed_s = "?";

	dev_info(host->dev,
		"AHCI %02x%02x.%02x%02x "
		"%u slots %u ports %s Gbps 0x%x impl %s mode\n"
		,

		(vers >> 24) & 0xff,
		(vers >> 16) & 0xff,
		(vers >> 8) & 0xff,
		vers & 0xff,

		((cap >> 8) & 0x1f) + 1,
		(cap & 0x1f) + 1,
		speed_s,
		impl,
		scc_s);

	dev_info(host->dev,
		"flags: "
		"%s%s%s%s%s%s%s"
		"%s%s%s%s%s%s%s"
		"%s%s%s%s%s%s\n"
		,

		cap & HOST_CAP_64 ? "64bit " : "",
		cap & HOST_CAP_NCQ ? "ncq " : "",
		cap & HOST_CAP_SNTF ? "sntf " : "",
		cap & HOST_CAP_MPS ? "ilck " : "",
		cap & HOST_CAP_SSS ? "stag " : "",
		cap & HOST_CAP_ALPM ? "pm " : "",
		cap & HOST_CAP_LED ? "led " : "",
		cap & HOST_CAP_CLO ? "clo " : "",
		cap & HOST_CAP_ONLY ? "only " : "",
		cap & HOST_CAP_PMP ? "pmp " : "",
		cap & HOST_CAP_FBS ? "fbs " : "",
		cap & HOST_CAP_PIO_MULTI ? "pio " : "",
		cap & HOST_CAP_SSC ? "slum " : "",
		cap & HOST_CAP_PART ? "part " : "",
		cap & HOST_CAP_CCC ? "ccc " : "",
		cap & HOST_CAP_EMS ? "ems " : "",
		cap & HOST_CAP_SXS ? "sxs " : "",
		cap2 & HOST_CAP2_APST ? "apst " : "",
		cap2 & HOST_CAP2_NVMHCI ? "nvmp " : "",
		cap2 & HOST_CAP2_BOH ? "boh " : ""
		);
}
EXPORT_SYMBOL_GPL(ahci_print_info);

void ahci_set_em_messages(struct ahci_host_priv *hpriv,
			  struct ata_port_info *pi)
{
	u8 messages;
	void __iomem *mmio = hpriv->mmio;
	u32 em_loc = readl(mmio + HOST_EM_LOC);
	u32 em_ctl = readl(mmio + HOST_EM_CTL);

	if (!ahci_em_messages || !(hpriv->cap & HOST_CAP_EMS))
		return;

	messages = (em_ctl & EM_CTRL_MSG_TYPE) >> 16;

	/* we only support LED message type right now */
	if ((messages & 0x01) && (ahci_em_messages == 1)) {
		/* store em_loc */
		hpriv->em_loc = ((em_loc >> 16) * 4);
		pi->flags |= ATA_FLAG_EM;
		if (!(em_ctl & EM_CTL_ALHD))
			pi->flags |= ATA_FLAG_SW_ACTIVITY;
	}
}
EXPORT_SYMBOL_GPL(ahci_set_em_messages);

MODULE_AUTHOR("Jeff Garzik");
MODULE_DESCRIPTION("Common AHCI SATA low-level routines");
MODULE_LICENSE("GPL");