/*
 * Copyright (C) 2005-2006 Dell Inc.
 *      Released under GPL v2.
 *
 * Serial Attached SCSI (SAS) transport class.
 *
 * The SAS transport class contains common code to deal with SAS HBAs,
 * an aproximated representation of SAS topologies in the driver model,
 * and various sysfs attributes to expose these topologies and management
 * interfaces to userspace.
 *
 * In addition to the basic SCSI core objects this transport class
 * introduces two additional intermediate objects:  The SAS PHY
 * as represented by struct sas_phy defines an "outgoing" PHY on
 * a SAS HBA or Expander, and the SAS remote PHY represented by
 * struct sas_rphy defines an "incoming" PHY on a SAS Expander or
 * end device.  Note that this is purely a software concept, the
 * underlying hardware for a PHY and a remote PHY is the exactly
 * the same.
 *
 * There is no concept of a SAS port in this code, users can see
 * what PHYs form a wide port based on the port_identifier attribute,
 * which is the same for all PHYs in a port.
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/jiffies.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/blkdev.h>
#include <linux/bsg.h>

#include <scsi/scsi.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_transport.h>
#include <scsi/scsi_transport_sas.h>

#include "scsi_sas_internal.h"
struct sas_host_attrs {
        struct list_head rphy_list;
        struct mutex lock;
        struct request_queue *q;
        u32 next_target_id;
        u32 next_expander_id;
        int next_port_id;
};
#define to_sas_host_attrs(host) ((struct sas_host_attrs *)(host)->shost_data)


/*
 * Hack to allow attributes of the same name in different objects.
 */
#define SAS_DEVICE_ATTR(_prefix,_name,_mode,_show,_store) \
        struct device_attribute dev_attr_##_prefix##_##_name = \
        __ATTR(_name,_mode,_show,_store)


/*
 * Pretty printing helpers
 */

#define sas_bitfield_name_match(title, table)                   \
static ssize_t                                                  \
get_sas_##title##_names(u32 table_key, char *buf)               \
{                                                               \
        char *prefix = "";                                      \
        ssize_t len = 0;                                        \
        int i;                                                  \
                                                                \
        for (i = 0; i < ARRAY_SIZE(table); i++) {               \
                if (table[i].value & table_key) {               \
                        len += sprintf(buf + len, "%s%s",       \
                                prefix, table[i].name);         \
                        prefix = ", ";                          \
                }                                               \
        }                                                       \
        len += sprintf(buf + len, "\n");                        \
        return len;                                             \
}

#define sas_bitfield_name_set(title, table)                     \
static ssize_t                                                  \
set_sas_##title##_names(u32 *table_key, const char *buf)        \
{                                                               \
        ssize_t len = 0;                                        \
        int i;                                                  \
                                                                \
        for (i = 0; i < ARRAY_SIZE(table); i++) {               \
                len = strlen(table[i].name);                    \
                if (strncmp(buf, table[i].name, len) == 0 &&    \
                    (buf[len] == '\n' || buf[len] == '\0')) {   \
                        *table_key = table[i].value;            \
                        return 0;                               \
                }                                               \
        }                                                       \
        return -EINVAL;                                         \
}

#define sas_bitfield_name_search(title, table)                  \
static ssize_t                                                  \
get_sas_##title##_names(u32 table_key, char *buf)               \
{                                                               \
        ssize_t len = 0;                                        \
        int i;                                                  \
                                                                \
        for (i = 0; i < ARRAY_SIZE(table); i++) {               \
                if (table[i].value == table_key) {              \
                        len += sprintf(buf + len, "%s",         \
                                table[i].name);                 \
                        break;                                  \
                }                                               \
        }                                                       \
        len += sprintf(buf + len, "\n");                        \
        return len;                                             \
}

static struct {
        u32             value;
        char            *name;
} sas_device_type_names[] = {
        { SAS_PHY_UNUSED,               "unused" },
        { SAS_END_DEVICE,               "end device" },
        { SAS_EDGE_EXPANDER_DEVICE,     "edge expander" },
        { SAS_FANOUT_EXPANDER_DEVICE,   "fanout expander" },
};
sas_bitfield_name_search(device_type, sas_device_type_names)


static struct {
        u32             value;
        char            *name;
} sas_protocol_names[] = {
        { SAS_PROTOCOL_SATA,            "sata" },
        { SAS_PROTOCOL_SMP,             "smp" },
        { SAS_PROTOCOL_STP,             "stp" },
        { SAS_PROTOCOL_SSP,             "ssp" },
};
sas_bitfield_name_match(protocol, sas_protocol_names)

static struct {
        u32             value;
        char            *name;
} sas_linkspeed_names[] = {
        { SAS_LINK_RATE_UNKNOWN,        "Unknown" },
        { SAS_PHY_DISABLED,             "Phy disabled" },
        { SAS_LINK_RATE_FAILED,         "Link Rate failed" },
        { SAS_SATA_SPINUP_HOLD,         "Spin-up hold" },
        { SAS_LINK_RATE_1_5_GBPS,       "1.5 Gbit" },
        { SAS_LINK_RATE_3_0_GBPS,       "3.0 Gbit" },
        { SAS_LINK_RATE_6_0_GBPS,       "6.0 Gbit" },
        { SAS_LINK_RATE_12_0_GBPS,      "12.0 Gbit" },
};
sas_bitfield_name_search(linkspeed, sas_linkspeed_names)
sas_bitfield_name_set(linkspeed, sas_linkspeed_names)

static struct sas_end_device *sas_sdev_to_rdev(struct scsi_device *sdev)
{
        struct sas_rphy *rphy = target_to_rphy(sdev->sdev_target);
        struct sas_end_device *rdev;

        BUG_ON(rphy->identify.device_type != SAS_END_DEVICE);

        rdev = rphy_to_end_device(rphy);
        return rdev;
}

static void sas_smp_request(struct request_queue *q, struct Scsi_Host *shost,
                            struct sas_rphy *rphy)
{
        struct request *req;
        int ret;
        int (*handler)(struct Scsi_Host *, struct sas_rphy *, struct request *);

        while ((req = blk_fetch_request(q)) != NULL) {
                spin_unlock_irq(q->queue_lock);

                handler = to_sas_internal(shost->transportt)->f->smp_handler;
                ret = handler(shost, rphy, req);
                req->errors = ret;

                blk_end_request_all(req, ret);

                spin_lock_irq(q->queue_lock);
        }
}

static void sas_host_smp_request(struct request_queue *q)
{
        sas_smp_request(q, (struct Scsi_Host *)q->queuedata, NULL);
}

static void sas_non_host_smp_request(struct request_queue *q)
{
        struct sas_rphy *rphy = q->queuedata;
        sas_smp_request(q, rphy_to_shost(rphy), rphy);
}

static void sas_host_release(struct device *dev)
{
        struct Scsi_Host *shost = dev_to_shost(dev);
        struct sas_host_attrs *sas_host = to_sas_host_attrs(shost);
        struct request_queue *q = sas_host->q;

        if (q)
                blk_cleanup_queue(q);
}

static int sas_bsg_initialize(struct Scsi_Host *shost, struct sas_rphy *rphy)
{
        struct request_queue *q;
        int error;
        struct device *dev;
        char namebuf[20];
        const char *name;
        void (*release)(struct device *);

        if (!to_sas_internal(shost->transportt)->f->smp_handler) {
                printk("%s can't handle SMP requests\n", shost->hostt->name);
                return 0;
        }

        if (rphy) {
                q = blk_init_queue(sas_non_host_smp_request, NULL);
                dev = &rphy->dev;
                name = dev_name(dev);
                release = NULL;
        } else {
                q = blk_init_queue(sas_host_smp_request, NULL);
                dev = &shost->shost_gendev;
                snprintf(namebuf, sizeof(namebuf),
                         "sas_host%d", shost->host_no);
                name = namebuf;
                release = sas_host_release;
        }
        if (!q)
                return -ENOMEM;

        error = bsg_register_queue(q, dev, name, release);
        if (error) {
                blk_cleanup_queue(q);
                return -ENOMEM;
        }

        if (rphy)
                rphy->q = q;
        else
                to_sas_host_attrs(shost)->q = q;

        if (rphy)
                q->queuedata = rphy;
        else
                q->queuedata = shost;

        queue_flag_set_unlocked(QUEUE_FLAG_BIDI, q);
        return 0;
}

static void sas_bsg_remove(struct Scsi_Host *shost, struct sas_rphy *rphy)
{
        struct request_queue *q;

        if (rphy)
                q = rphy->q;
        else
                q = to_sas_host_attrs(shost)->q;

        if (!q)
                return;

        bsg_unregister_queue(q);
}

/*
 * SAS host attributes
 */

static int sas_host_setup(struct transport_container *tc, struct device *dev,
                          struct device *cdev)
{
        struct Scsi_Host *shost = dev_to_shost(dev);
        struct sas_host_attrs *sas_host = to_sas_host_attrs(shost);

        INIT_LIST_HEAD(&sas_host->rphy_list);
        mutex_init(&sas_host->lock);
        sas_host->next_target_id = 0;
        sas_host->next_expander_id = 0;
        sas_host->next_port_id = 0;

        if (sas_bsg_initialize(shost, NULL))
                dev_printk(KERN_ERR, dev, "fail to a bsg device %d\n",
                           shost->host_no);

        return 0;
}

static int sas_host_remove(struct transport_container *tc, struct device *dev,
                           struct device *cdev)
{
        struct Scsi_Host *shost = dev_to_shost(dev);

        sas_bsg_remove(shost, NULL);

        return 0;
}

static DECLARE_TRANSPORT_CLASS(sas_host_class,
                "sas_host", sas_host_setup, sas_host_remove, NULL);

static int sas_host_match(struct attribute_container *cont,
                            struct device *dev)
{
        struct Scsi_Host *shost;
        struct sas_internal *i;

        if (!scsi_is_host_device(dev))
                return 0;
        shost = dev_to_shost(dev);

        if (!shost->transportt)
                return 0;
        if (shost->transportt->host_attrs.ac.class !=
                        &sas_host_class.class)
                return 0;

        i = to_sas_internal(shost->transportt);
        return &i->t.host_attrs.ac == cont;
}

static int do_sas_phy_delete(struct device *dev, void *data)
{
        int pass = (int)(unsigned long)data;

        if (pass == 0 && scsi_is_sas_port(dev))
                sas_port_delete(dev_to_sas_port(dev));
        else if (pass == 1 && scsi_is_sas_phy(dev))
                sas_phy_delete(dev_to_phy(dev));
        return 0;
}

/**
 * sas_remove_children  -  tear down a devices SAS data structures
 * @dev:        device belonging to the sas object
 *
 * Removes all SAS PHYs and remote PHYs for a given object
 */
void sas_remove_children(struct device *dev)
{
        device_for_each_child(dev, (void *)0, do_sas_phy_delete);
        device_for_each_child(dev, (void *)1, do_sas_phy_delete);
}
EXPORT_SYMBOL(sas_remove_children);

/**
 * sas_remove_host  -  tear down a Scsi_Host's SAS data structures
 * @shost:      Scsi Host that is torn down
 *
 * Removes all SAS PHYs and remote PHYs for a given Scsi_Host.
 * Must be called just before scsi_remove_host for SAS HBAs.
 */
void sas_remove_host(struct Scsi_Host *shost)
{
        sas_remove_children(&shost->shost_gendev);
}
EXPORT_SYMBOL(sas_remove_host);

/**
 * sas_get_address - return the SAS address of the device
 * @sdev: scsi device
 *
 * Returns the SAS address of the scsi device
 */
u64 sas_get_address(struct scsi_device *sdev)
{
        struct sas_end_device *rdev = sas_sdev_to_rdev(sdev);

        return rdev->rphy.identify.sas_address;
}
EXPORT_SYMBOL(sas_get_address);

/**
 * sas_tlr_supported - checking TLR bit in vpd 0x90
 * @sdev: scsi device struct
 *
 * Check Transport Layer Retries are supported or not.
 * If vpd page 0x90 is present, TRL is supported.
 *
 */
unsigned int
sas_tlr_supported(struct scsi_device *sdev)
{
        const int vpd_len = 32;
        struct sas_end_device *rdev = sas_sdev_to_rdev(sdev);
        char *buffer = kzalloc(vpd_len, GFP_KERNEL);
        int ret = 0;

        if (scsi_get_vpd_page(sdev, 0x90, buffer, vpd_len))
                goto out;

        /*
         * Magic numbers: the VPD Protocol page (0x90)
         * has a 4 byte header and then one entry per device port
         * the TLR bit is at offset 8 on each port entry
         * if we take the first port, that's at total offset 12
         */
        ret = buffer[12] & 0x01;

 out:
        kfree(buffer);
        rdev->tlr_supported = ret;
        return ret;

}
EXPORT_SYMBOL_GPL(sas_tlr_supported);

/**
 * sas_disable_tlr - setting TLR flags
 * @sdev: scsi device struct
 *
 * Seting tlr_enabled flag to 0.
 *
 */
void
sas_disable_tlr(struct scsi_device *sdev)
{
        struct sas_end_device *rdev = sas_sdev_to_rdev(sdev);

        rdev->tlr_enabled = 0;
}
EXPORT_SYMBOL_GPL(sas_disable_tlr);

/**
 * sas_enable_tlr - setting TLR flags
 * @sdev: scsi device struct
 *
 * Seting tlr_enabled flag 1.
 *
 */
void sas_enable_tlr(struct scsi_device *sdev)
{
        unsigned int tlr_supported = 0;
        tlr_supported  = sas_tlr_supported(sdev);

        if (tlr_supported) {
                struct sas_end_device *rdev = sas_sdev_to_rdev(sdev);

                rdev->tlr_enabled = 1;
        }

        return;
}
EXPORT_SYMBOL_GPL(sas_enable_tlr);

unsigned int sas_is_tlr_enabled(struct scsi_device *sdev)
{
        struct sas_end_device *rdev = sas_sdev_to_rdev(sdev);
        return rdev->tlr_enabled;
}
EXPORT_SYMBOL_GPL(sas_is_tlr_enabled);

/*
 * SAS Phy attributes
 */

#define sas_phy_show_simple(field, name, format_string, cast)           \
static ssize_t                                                          \
show_sas_phy_##name(struct device *dev,                                 \
                    struct device_attribute *attr, char *buf)           \
{                                                                       \
        struct sas_phy *phy = transport_class_to_phy(dev);              \
                                                                        \
        return snprintf(buf, 20, format_string, cast phy->field);       \
}

#define sas_phy_simple_attr(field, name, format_string, type)           \
        sas_phy_show_simple(field, name, format_string, (type)) \
static DEVICE_ATTR(name, S_IRUGO, show_sas_phy_##name, NULL)

#define sas_phy_show_protocol(field, name)                              \
static ssize_t                                                          \
show_sas_phy_##name(struct device *dev,                                 \
                    struct device_attribute *attr, char *buf)           \
{                                                                       \
        struct sas_phy *phy = transport_class_to_phy(dev);              \
                                                                        \
        if (!phy->field)                                                \
                return snprintf(buf, 20, "none\n");                     \
        return get_sas_protocol_names(phy->field, buf);         \
}

#define sas_phy_protocol_attr(field, name)                              \
        sas_phy_show_protocol(field, name)                              \
static DEVICE_ATTR(name, S_IRUGO, show_sas_phy_##name, NULL)

#define sas_phy_show_linkspeed(field)                                   \
static ssize_t                                                          \
show_sas_phy_##field(struct device *dev,                                \
                     struct device_attribute *attr, char *buf)          \
{                                                                       \
        struct sas_phy *phy = transport_class_to_phy(dev);              \
                                                                        \
        return get_sas_linkspeed_names(phy->field, buf);                \
}

/* Fudge to tell if we're minimum or maximum */
#define sas_phy_store_linkspeed(field)                                  \
static ssize_t                                                          \
store_sas_phy_##field(struct device *dev,                               \
                      struct device_attribute *attr,                    \
                      const char *buf,  size_t count)                   \
{                                                                       \
        struct sas_phy *phy = transport_class_to_phy(dev);              \
        struct Scsi_Host *shost = dev_to_shost(phy->dev.parent);        \
        struct sas_internal *i = to_sas_internal(shost->transportt);    \
        u32 value;                                                      \
        struct sas_phy_linkrates rates = {0};                           \
        int error;                                                      \
                                                                        \
        error = set_sas_linkspeed_names(&value, buf);                   \
        if (error)                                                      \
                return error;                                           \
        rates.field = value;                                            \
        error = i->f->set_phy_speed(phy, &rates);                       \
                                                                        \
        return error ? error : count;                                   \
}

#define sas_phy_linkspeed_rw_attr(field)                                \
        sas_phy_show_linkspeed(field)                                   \
        sas_phy_store_linkspeed(field)                                  \
static DEVICE_ATTR(field, S_IRUGO, show_sas_phy_##field,                \
        store_sas_phy_##field)

#define sas_phy_linkspeed_attr(field)                                   \
        sas_phy_show_linkspeed(field)                                   \
static DEVICE_ATTR(field, S_IRUGO, show_sas_phy_##field, NULL)


#define sas_phy_show_linkerror(field)                                   \
static ssize_t                                                          \
show_sas_phy_##field(struct device *dev,                                \
                     struct device_attribute *attr, char *buf)          \
{                                                                       \
        struct sas_phy *phy = transport_class_to_phy(dev);              \
        struct Scsi_Host *shost = dev_to_shost(phy->dev.parent);        \
        struct sas_internal *i = to_sas_internal(shost->transportt);    \
        int error;                                                      \
                                                                        \
        error = i->f->get_linkerrors ? i->f->get_linkerrors(phy) : 0;   \
        if (error)                                                      \
                return error;                                           \
        return snprintf(buf, 20, "%u\n", phy->field);                   \
}

#define sas_phy_linkerror_attr(field)                                   \
        sas_phy_show_linkerror(field)                                   \
static DEVICE_ATTR(field, S_IRUGO, show_sas_phy_##field, NULL)


static ssize_t
show_sas_device_type(struct device *dev,
                     struct device_attribute *attr, char *buf)
{
        struct sas_phy *phy = transport_class_to_phy(dev);

        if (!phy->identify.device_type)
                return snprintf(buf, 20, "none\n");
        return get_sas_device_type_names(phy->identify.device_type, buf);
}
static DEVICE_ATTR(device_type, S_IRUGO, show_sas_device_type, NULL);

static ssize_t do_sas_phy_enable(struct device *dev,
                size_t count, int enable)
{
        struct sas_phy *phy = transport_class_to_phy(dev);
        struct Scsi_Host *shost = dev_to_shost(phy->dev.parent);
        struct sas_internal *i = to_sas_internal(shost->transportt);
        int error;

        error = i->f->phy_enable(phy, enable);
        if (error)
                return error;
        phy->enabled = enable;
        return count;
};

static ssize_t
store_sas_phy_enable(struct device *dev, struct device_attribute *attr,
                     const char *buf, size_t count)
{
        if (count < 1)
                return -EINVAL;

        switch (buf[0]) {
        case '0':
                do_sas_phy_enable(dev, count, 0);
                break;
        case '1':
                do_sas_phy_enable(dev, count, 1);
                break;
        default:
                return -EINVAL;
        }

        return count;
}

static ssize_t
show_sas_phy_enable(struct device *dev, struct device_attribute *attr,
                    char *buf)
{
        struct sas_phy *phy = transport_class_to_phy(dev);

        return snprintf(buf, 20, "%d", phy->enabled);
}

static DEVICE_ATTR(enable, S_IRUGO | S_IWUSR, show_sas_phy_enable,
                         store_sas_phy_enable);

static ssize_t
do_sas_phy_reset(struct device *dev, size_t count, int hard_reset)
{
        struct sas_phy *phy = transport_class_to_phy(dev);
        struct Scsi_Host *shost = dev_to_shost(phy->dev.parent);
        struct sas_internal *i = to_sas_internal(shost->transportt);
        int error;

        error = i->f->phy_reset(phy, hard_reset);
        if (error)
                return error;
        phy->enabled = 1;
        return count;
};

static ssize_t
store_sas_link_reset(struct device *dev, struct device_attribute *attr,
                     const char *buf, size_t count)
{
        return do_sas_phy_reset(dev, count, 0);
}
static DEVICE_ATTR(link_reset, S_IWUSR, NULL, store_sas_link_reset);

static ssize_t
store_sas_hard_reset(struct device *dev, struct device_attribute *attr,
                     const char *buf, size_t count)
{
        return do_sas_phy_reset(dev, count, 1);
}
static DEVICE_ATTR(hard_reset, S_IWUSR, NULL, store_sas_hard_reset);

sas_phy_protocol_attr(identify.initiator_port_protocols,
                initiator_port_protocols);
sas_phy_protocol_attr(identify.target_port_protocols,
                target_port_protocols);
sas_phy_simple_attr(identify.sas_address, sas_address, "0x%016llx\n",
                unsigned long long);
sas_phy_simple_attr(identify.phy_identifier, phy_identifier, "%d\n", u8);
//sas_phy_simple_attr(port_identifier, port_identifier, "%d\n", int);
sas_phy_linkspeed_attr(negotiated_linkrate);
sas_phy_linkspeed_attr(minimum_linkrate_hw);
sas_phy_linkspeed_rw_attr(minimum_linkrate);
sas_phy_linkspeed_attr(maximum_linkrate_hw);
sas_phy_linkspeed_rw_attr(maximum_linkrate);
sas_phy_linkerror_attr(invalid_dword_count);
sas_phy_linkerror_attr(running_disparity_error_count);
sas_phy_linkerror_attr(loss_of_dword_sync_count);
sas_phy_linkerror_attr(phy_reset_problem_count);

static int sas_phy_setup(struct transport_container *tc, struct device *dev,
                         struct device *cdev)
{
        struct sas_phy *phy = dev_to_phy(dev);
        struct Scsi_Host *shost = dev_to_shost(phy->dev.parent);
        struct sas_internal *i = to_sas_internal(shost->transportt);

        if (i->f->phy_setup)
                i->f->phy_setup(phy);

        return 0;
}

static DECLARE_TRANSPORT_CLASS(sas_phy_class,
                "sas_phy", sas_phy_setup, NULL, NULL);

static int sas_phy_match(struct attribute_container *cont, struct device *dev)
{
        struct Scsi_Host *shost;
        struct sas_internal *i;

        if (!scsi_is_sas_phy(dev))
                return 0;
        shost = dev_to_shost(dev->parent);

        if (!shost->transportt)
                return 0;
        if (shost->transportt->host_attrs.ac.class !=
                        &sas_host_class.class)
                return 0;

        i = to_sas_internal(shost->transportt);
        return &i->phy_attr_cont.ac == cont;
}

static void sas_phy_release(struct device *dev)
{
        struct sas_phy *phy = dev_to_phy(dev);
        struct Scsi_Host *shost = dev_to_shost(phy->dev.parent);
        struct sas_internal *i = to_sas_internal(shost->transportt);

        if (i->f->phy_release)
                i->f->phy_release(phy);
        put_device(dev->parent);
        kfree(phy);
}

/**
 * sas_phy_alloc  -  allocates and initialize a SAS PHY structure
 * @parent:     Parent device
 * @number:     Phy index
 *
 * Allocates an SAS PHY structure.  It will be added in the device tree
 * below the device specified by @parent, which has to be either a Scsi_Host
 * or sas_rphy.
 *
 * Returns:
 *      SAS PHY allocated or %NULL if the allocation failed.
 */
struct sas_phy *sas_phy_alloc(struct device *parent, int number)
{
        struct Scsi_Host *shost = dev_to_shost(parent);
        struct sas_phy *phy;

        phy = kzalloc(sizeof(*phy), GFP_KERNEL);
        if (!phy)
                return NULL;

        phy->number = number;
        phy->enabled = 1;

        device_initialize(&phy->dev);
        phy->dev.parent = get_device(parent);
        phy->dev.release = sas_phy_release;
        INIT_LIST_HEAD(&phy->port_siblings);
        if (scsi_is_sas_expander_device(parent)) {
                struct sas_rphy *rphy = dev_to_rphy(parent);
                dev_set_name(&phy->dev, "phy-%d:%d:%d", shost->host_no,
                        rphy->scsi_target_id, number);
        } else
                dev_set_name(&phy->dev, "phy-%d:%d", shost->host_no, number);

        transport_setup_device(&phy->dev);

        return phy;
}
EXPORT_SYMBOL(sas_phy_alloc);

/**
 * sas_phy_add  -  add a SAS PHY to the device hierarchy
 * @phy:        The PHY to be added
 *
 * Publishes a SAS PHY to the rest of the system.
 */
int sas_phy_add(struct sas_phy *phy)
{
        int error;

        error = device_add(&phy->dev);
        if (!error) {
                transport_add_device(&phy->dev);
                transport_configure_device(&phy->dev);
        }

        return error;
}
EXPORT_SYMBOL(sas_phy_add);

/**
 * sas_phy_free  -  free a SAS PHY
 * @phy:        SAS PHY to free
 *
 * Frees the specified SAS PHY.
 *
 * Note:
 *   This function must only be called on a PHY that has not
 *   successfully been added using sas_phy_add().
 */
void sas_phy_free(struct sas_phy *phy)
{
        transport_destroy_device(&phy->dev);
        put_device(&phy->dev);
}
EXPORT_SYMBOL(sas_phy_free);

/**
 * sas_phy_delete  -  remove SAS PHY
 * @phy:        SAS PHY to remove
 *
 * Removes the specified SAS PHY.  If the SAS PHY has an
 * associated remote PHY it is removed before.
 */
void
sas_phy_delete(struct sas_phy *phy)
{
        struct device *dev = &phy->dev;

        /* this happens if the phy is still part of a port when deleted */
        BUG_ON(!list_empty(&phy->port_siblings));

        transport_remove_device(dev);
        device_del(dev);
        transport_destroy_device(dev);
        put_device(dev);
}
EXPORT_SYMBOL(sas_phy_delete);

/**
 * scsi_is_sas_phy  -  check if a struct device represents a SAS PHY
 * @dev:        device to check
 *
 * Returns:
 *      %1 if the device represents a SAS PHY, %0 else
 */
int scsi_is_sas_phy(const struct device *dev)
{
        return dev->release == sas_phy_release;
}
EXPORT_SYMBOL(scsi_is_sas_phy);

/*
 * SAS Port attributes
 */
#define sas_port_show_simple(field, name, format_string, cast)          \
static ssize_t                                                          \
show_sas_port_##name(struct device *dev,                                \
                     struct device_attribute *attr, char *buf)          \
{                                                                       \
        struct sas_port *port = transport_class_to_sas_port(dev);       \
                                                                        \
        return snprintf(buf, 20, format_string, cast port->field);      \
}

#define sas_port_simple_attr(field, name, format_string, type)          \
        sas_port_show_simple(field, name, format_string, (type))        \
static DEVICE_ATTR(name, S_IRUGO, show_sas_port_##name, NULL)

sas_port_simple_attr(num_phys, num_phys, "%d\n", int);

static DECLARE_TRANSPORT_CLASS(sas_port_class,
                               "sas_port", NULL, NULL, NULL);

static int sas_port_match(struct attribute_container *cont, struct device *dev)
{
        struct Scsi_Host *shost;
        struct sas_internal *i;

        if (!scsi_is_sas_port(dev))
                return 0;
        shost = dev_to_shost(dev->parent);

        if (!shost->transportt)
                return 0;
        if (shost->transportt->host_attrs.ac.class !=
                        &sas_host_class.class)
                return 0;

        i = to_sas_internal(shost->transportt);
        return &i->port_attr_cont.ac == cont;
}


static void sas_port_release(struct device *dev)
{
        struct sas_port *port = dev_to_sas_port(dev);

        BUG_ON(!list_empty(&port->phy_list));

        put_device(dev->parent);
        kfree(port);
}

static void sas_port_create_link(struct sas_port *port,
                                 struct sas_phy *phy)
{
        int res;

        res = sysfs_create_link(&port->dev.kobj, &phy->dev.kobj,
                                dev_name(&phy->dev));
        if (res)
                goto err;
        res = sysfs_create_link(&phy->dev.kobj, &port->dev.kobj, "port");
        if (res)
                goto err;
        return;
err:
        printk(KERN_ERR "%s: Cannot create port links, err=%d\n",
               __func__, res);
}

static void sas_port_delete_link(struct sas_port *port,
                                 struct sas_phy *phy)
{
        sysfs_remove_link(&port->dev.kobj, dev_name(&phy->dev));
        sysfs_remove_link(&phy->dev.kobj, "port");
}

/** sas_port_alloc - allocate and initialize a SAS port structure
 *
 * @parent:     parent device
 * @port_id:    port number
 *
 * Allocates a SAS port structure.  It will be added to the device tree
 * below the device specified by @parent which must be either a Scsi_Host
 * or a sas_expander_device.
 *
 * Returns %NULL on error
 */
struct sas_port *sas_port_alloc(struct device *parent, int port_id)
{
        struct Scsi_Host *shost = dev_to_shost(parent);
        struct sas_port *port;

        port = kzalloc(sizeof(*port), GFP_KERNEL);
        if (!port)
                return NULL;

        port->port_identifier = port_id;

        device_initialize(&port->dev);

        port->dev.parent = get_device(parent);
        port->dev.release = sas_port_release;

        mutex_init(&port->phy_list_mutex);
        INIT_LIST_HEAD(&port->phy_list);

        if (scsi_is_sas_expander_device(parent)) {
                struct sas_rphy *rphy = dev_to_rphy(parent);
                dev_set_name(&port->dev, "port-%d:%d:%d", shost->host_no,
                             rphy->scsi_target_id, port->port_identifier);
        } else
                dev_set_name(&port->dev, "port-%d:%d", shost->host_no,
                             port->port_identifier);

        transport_setup_device(&port->dev);

        return port;
}
EXPORT_SYMBOL(sas_port_alloc);

/** sas_port_alloc_num - allocate and initialize a SAS port structure
 *
 * @parent:     parent device
 *
 * Allocates a SAS port structure and a number to go with it.  This
 * interface is really for adapters where the port number has no
 * meansing, so the sas class should manage them.  It will be added to
 * the device tree below the device specified by @parent which must be
 * either a Scsi_Host or a sas_expander_device.
 *
 * Returns %NULL on error
 */
struct sas_port *sas_port_alloc_num(struct device *parent)
{
        int index;
        struct Scsi_Host *shost = dev_to_shost(parent);
        struct sas_host_attrs *sas_host = to_sas_host_attrs(shost);

        /* FIXME: use idr for this eventually */
        mutex_lock(&sas_host->lock);
        if (scsi_is_sas_expander_device(parent)) {
                struct sas_rphy *rphy = dev_to_rphy(parent);
                struct sas_expander_device *exp = rphy_to_expander_device(rphy);

                index = exp->next_port_id++;
        } else
                index = sas_host->next_port_id++;
        mutex_unlock(&sas_host->lock);
        return sas_port_alloc(parent, index);
}
EXPORT_SYMBOL(sas_port_alloc_num);

/**
 * sas_port_add - add a SAS port to the device hierarchy
 * @port:       port to be added
 *
 * publishes a port to the rest of the system
 */
int sas_port_add(struct sas_port *port)
{
        int error;

        /* No phys should be added until this is made visible */
        BUG_ON(!list_empty(&port->phy_list));

        error = device_add(&port->dev);

        if (error)
                return error;

        transport_add_device(&port->dev);
        transport_configure_device(&port->dev);

        return 0;
}
EXPORT_SYMBOL(sas_port_add);

/**
 * sas_port_free  -  free a SAS PORT
 * @port:       SAS PORT to free
 *
 * Frees the specified SAS PORT.
 *
 * Note:
 *   This function must only be called on a PORT that has not
 *   successfully been added using sas_port_add().
 */
void sas_port_free(struct sas_port *port)
{
        transport_destroy_device(&port->dev);
        put_device(&port->dev);
}
EXPORT_SYMBOL(sas_port_free);

/**
 * sas_port_delete  -  remove SAS PORT
 * @port:       SAS PORT to remove
 *
 * Removes the specified SAS PORT.  If the SAS PORT has an
 * associated phys, unlink them from the port as well.
 */
void sas_port_delete(struct sas_port *port)
{
        struct device *dev = &port->dev;
        struct sas_phy *phy, *tmp_phy;

        if (port->rphy) {
                sas_rphy_delete(port->rphy);
                port->rphy = NULL;
        }

        mutex_lock(&port->phy_list_mutex);
        list_for_each_entry_safe(phy, tmp_phy, &port->phy_list,
                                 port_siblings) {
                sas_port_delete_link(port, phy);
                list_del_init(&phy->port_siblings);
        }
        mutex_unlock(&port->phy_list_mutex);

        if (port->is_backlink) {
                struct device *parent = port->dev.parent;

                sysfs_remove_link(&port->dev.kobj, dev_name(parent));
                port->is_backlink = 0;
        }

        transport_remove_device(dev);
        device_del(dev);
        transport_destroy_device(dev);
        put_device(dev);
}
EXPORT_SYMBOL(sas_port_delete);

/**
 * scsi_is_sas_port -  check if a struct device represents a SAS port
 * @dev:        device to check
 *
 * Returns:
 *      %1 if the device represents a SAS Port, %0 else
 */
int scsi_is_sas_port(const struct device *dev)
{
        return dev->release == sas_port_release;
}
EXPORT_SYMBOL(scsi_is_sas_port);

/**
 * sas_port_get_phy - try to take a reference on a port member
 * @port: port to check
 */
struct sas_phy *sas_port_get_phy(struct sas_port *port)
{
        struct sas_phy *phy;

        mutex_lock(&port->phy_list_mutex);
        if (list_empty(&port->phy_list))
                phy = NULL;
        else {
                struct list_head *ent = port->phy_list.next;

                phy = list_entry(ent, typeof(*phy), port_siblings);
                get_device(&phy->dev);
        }
        mutex_unlock(&port->phy_list_mutex);

        return phy;
}
EXPORT_SYMBOL(sas_port_get_phy);

/**
 * sas_port_add_phy - add another phy to a port to form a wide port
 * @port:       port to add the phy to
 * @phy:        phy to add
 *
 * When a port is initially created, it is empty (has no phys).  All
 * ports must have at least one phy to operated, and all wide ports
 * must have at least two.  The current code makes no difference
 * between ports and wide ports, but the only object that can be
 * connected to a remote device is a port, so ports must be formed on
 * all devices with phys if they're connected to anything.
 */
void sas_port_add_phy(struct sas_port *port, struct sas_phy *phy)
{
        mutex_lock(&port->phy_list_mutex);
        if (unlikely(!list_empty(&phy->port_siblings))) {
                /* make sure we're already on this port */
                struct sas_phy *tmp;

                list_for_each_entry(tmp, &port->phy_list, port_siblings)
                        if (tmp == phy)
                                break;
                /* If this trips, you added a phy that was already
                 * part of a different port */
                if (unlikely(tmp != phy)) {
                        dev_printk(KERN_ERR, &port->dev, "trying to add phy %s fails: it's already part of another port\n",
                                   dev_name(&phy->dev));
                        BUG();
                }
        } else {
                sas_port_create_link(port, phy);
                list_add_tail(&phy->port_siblings, &port->phy_list);
                port->num_phys++;
        }
        mutex_unlock(&port->phy_list_mutex);
}
EXPORT_SYMBOL(sas_port_add_phy);

/**
 * sas_port_delete_phy - remove a phy from a port or wide port
 * @port:       port to remove the phy from
 * @phy:        phy to remove
 *
 * This operation is used for tearing down ports again.  It must be
 * done to every port or wide port before calling sas_port_delete.
 */
void sas_port_delete_phy(struct sas_port *port, struct sas_phy *phy)
{
        mutex_lock(&port->phy_list_mutex);
        sas_port_delete_link(port, phy);
        list_del_init(&phy->port_siblings);
        port->num_phys--;
        mutex_unlock(&port->phy_list_mutex);
}
EXPORT_SYMBOL(sas_port_delete_phy);

void sas_port_mark_backlink(struct sas_port *port)
{
        int res;
        struct device *parent = port->dev.parent->parent->parent;

        if (port->is_backlink)
                return;
        port->is_backlink = 1;
        res = sysfs_create_link(&port->dev.kobj, &parent->kobj,
                                dev_name(parent));
        if (res)
                goto err;
        return;
err:
        printk(KERN_ERR "%s: Cannot create port backlink, err=%d\n",
               __func__, res);

}
EXPORT_SYMBOL(sas_port_mark_backlink);

/*
 * SAS remote PHY attributes.
 */

#define sas_rphy_show_simple(field, name, format_string, cast)          \
static ssize_t                                                          \
show_sas_rphy_##name(struct device *dev,                                \
                     struct device_attribute *attr, char *buf)          \
{                                                                       \
        struct sas_rphy *rphy = transport_class_to_rphy(dev);           \
                                                                        \
        return snprintf(buf, 20, format_string, cast rphy->field);      \
}

#define sas_rphy_simple_attr(field, name, format_string, type)          \
        sas_rphy_show_simple(field, name, format_string, (type))        \
static SAS_DEVICE_ATTR(rphy, name, S_IRUGO,                     \
                show_sas_rphy_##name, NULL)

#define sas_rphy_show_protocol(field, name)                             \
static ssize_t                                                          \
show_sas_rphy_##name(struct device *dev,                                \
                     struct device_attribute *attr, char *buf)          \
{                                                                       \
        struct sas_rphy *rphy = transport_class_to_rphy(dev);           \
                                                                        \
        if (!rphy->field)                                       \
                return snprintf(buf, 20, "none\n");                     \
        return get_sas_protocol_names(rphy->field, buf);        \
}

#define sas_rphy_protocol_attr(field, name)                             \
        sas_rphy_show_protocol(field, name)                             \
static SAS_DEVICE_ATTR(rphy, name, S_IRUGO,                     \
                show_sas_rphy_##name, NULL)

static ssize_t
show_sas_rphy_device_type(struct device *dev,
                          struct device_attribute *attr, char *buf)
{
        struct sas_rphy *rphy = transport_class_to_rphy(dev);

        if (!rphy->identify.device_type)
                return snprintf(buf, 20, "none\n");
        return get_sas_device_type_names(
                        rphy->identify.device_type, buf);
}

static SAS_DEVICE_ATTR(rphy, device_type, S_IRUGO,
                show_sas_rphy_device_type, NULL);

static ssize_t
show_sas_rphy_enclosure_identifier(struct device *dev,
                                   struct device_attribute *attr, char *buf)
{
        struct sas_rphy *rphy = transport_class_to_rphy(dev);
        struct sas_phy *phy = dev_to_phy(rphy->dev.parent);
        struct Scsi_Host *shost = dev_to_shost(phy->dev.parent);
        struct sas_internal *i = to_sas_internal(shost->transportt);
        u64 identifier;
        int error;

        error = i->f->get_enclosure_identifier(rphy, &identifier);
        if (error)
                return error;
        return sprintf(buf, "0x%llx\n", (unsigned long long)identifier);
}

static SAS_DEVICE_ATTR(rphy, enclosure_identifier, S_IRUGO,
                show_sas_rphy_enclosure_identifier, NULL);

static ssize_t
show_sas_rphy_bay_identifier(struct device *dev,
                             struct device_attribute *attr, char *buf)
{
        struct sas_rphy *rphy = transport_class_to_rphy(dev);
        struct sas_phy *phy = dev_to_phy(rphy->dev.parent);
        struct Scsi_Host *shost = dev_to_shost(phy->dev.parent);
        struct sas_internal *i = to_sas_internal(shost->transportt);
        int val;

        val = i->f->get_bay_identifier(rphy);
        if (val < 0)
                return val;
        return sprintf(buf, "%d\n", val);
}

static SAS_DEVICE_ATTR(rphy, bay_identifier, S_IRUGO,
                show_sas_rphy_bay_identifier, NULL);

sas_rphy_protocol_attr(identify.initiator_port_protocols,
                initiator_port_protocols);
sas_rphy_protocol_attr(identify.target_port_protocols, target_port_protocols);
sas_rphy_simple_attr(identify.sas_address, sas_address, "0x%016llx\n",
                unsigned long long);
sas_rphy_simple_attr(identify.phy_identifier, phy_identifier, "%d\n", u8);
sas_rphy_simple_attr(scsi_target_id, scsi_target_id, "%d\n", u32);

/* only need 8 bytes of data plus header (4 or 8) */
#define BUF_SIZE 64

int sas_read_port_mode_page(struct scsi_device *sdev)
{
        char *buffer = kzalloc(BUF_SIZE, GFP_KERNEL), *msdata;
        struct sas_end_device *rdev = sas_sdev_to_rdev(sdev);
        struct scsi_mode_data mode_data;
        int res, error;

        if (!buffer)
                return -ENOMEM;

        res = scsi_mode_sense(sdev, 1, 0x19, buffer, BUF_SIZE, 30*HZ, 3,
                              &mode_data, NULL);

        error = -EINVAL;
        if (!scsi_status_is_good(res))
                goto out;

        msdata = buffer +  mode_data.header_length +
                mode_data.block_descriptor_length;

        if (msdata - buffer > BUF_SIZE - 8)
                goto out;

        error = 0;

        rdev->ready_led_meaning = msdata[2] & 0x10 ? 1 : 0;
        rdev->I_T_nexus_loss_timeout = (msdata[4] << 8) + msdata[5];
        rdev->initiator_response_timeout = (msdata[6] << 8) + msdata[7];

 out:
        kfree(buffer);
        return error;
}
EXPORT_SYMBOL(sas_read_port_mode_page);

static DECLARE_TRANSPORT_CLASS(sas_end_dev_class,
                               "sas_end_device", NULL, NULL, NULL);

#define sas_end_dev_show_simple(field, name, format_string, cast)       \
static ssize_t                                                          \
show_sas_end_dev_##name(struct device *dev,                             \
                        struct device_attribute *attr, char *buf)       \
{                                                                       \
        struct sas_rphy *rphy = transport_class_to_rphy(dev);           \
        struct sas_end_device *rdev = rphy_to_end_device(rphy);         \
                                                                        \
        return snprintf(buf, 20, format_string, cast rdev->field);      \
}

#define sas_end_dev_simple_attr(field, name, format_string, type)       \
        sas_end_dev_show_simple(field, name, format_string, (type))     \
static SAS_DEVICE_ATTR(end_dev, name, S_IRUGO,                  \
                show_sas_end_dev_##name, NULL)

sas_end_dev_simple_attr(ready_led_meaning, ready_led_meaning, "%d\n", int);
sas_end_dev_simple_attr(I_T_nexus_loss_timeout, I_T_nexus_loss_timeout,
                        "%d\n", int);
sas_end_dev_simple_attr(initiator_response_timeout, initiator_response_timeout,
                        "%d\n", int);
sas_end_dev_simple_attr(tlr_supported, tlr_supported,
                        "%d\n", int);
sas_end_dev_simple_attr(tlr_enabled, tlr_enabled,
                        "%d\n", int);

static DECLARE_TRANSPORT_CLASS(sas_expander_class,
                               "sas_expander", NULL, NULL, NULL);

#define sas_expander_show_simple(field, name, format_string, cast)      \
static ssize_t                                                          \
show_sas_expander_##name(struct device *dev,                            \
                         struct device_attribute *attr, char *buf)      \
{                                                                       \
        struct sas_rphy *rphy = transport_class_to_rphy(dev);           \
        struct sas_expander_device *edev = rphy_to_expander_device(rphy); \
                                                                        \
        return snprintf(buf, 20, format_string, cast edev->field);      \
}

#define sas_expander_simple_attr(field, name, format_string, type)      \
        sas_expander_show_simple(field, name, format_string, (type))    \
static SAS_DEVICE_ATTR(expander, name, S_IRUGO,                         \
                show_sas_expander_##name, NULL)

sas_expander_simple_attr(vendor_id, vendor_id, "%s\n", char *);
sas_expander_simple_attr(product_id, product_id, "%s\n", char *);
sas_expander_simple_attr(product_rev, product_rev, "%s\n", char *);
sas_expander_simple_attr(component_vendor_id, component_vendor_id,
                         "%s\n", char *);
sas_expander_simple_attr(component_id, component_id, "%u\n", unsigned int);
sas_expander_simple_attr(component_revision_id, component_revision_id, "%u\n",
                         unsigned int);
sas_expander_simple_attr(level, level, "%d\n", int);

static DECLARE_TRANSPORT_CLASS(sas_rphy_class,
                "sas_device", NULL, NULL, NULL);

static int sas_rphy_match(struct attribute_container *cont, struct device *dev)
{
        struct Scsi_Host *shost;
        struct sas_internal *i;

        if (!scsi_is_sas_rphy(dev))
                return 0;
        shost = dev_to_shost(dev->parent->parent);

        if (!shost->transportt)
                return 0;
        if (shost->transportt->host_attrs.ac.class !=
                        &sas_host_class.class)
                return 0;

        i = to_sas_internal(shost->transportt);
        return &i->rphy_attr_cont.ac == cont;
}

static int sas_end_dev_match(struct attribute_container *cont,
                             struct device *dev)
{
        struct Scsi_Host *shost;
        struct sas_internal *i;
        struct sas_rphy *rphy;

        if (!scsi_is_sas_rphy(dev))
                return 0;
        shost = dev_to_shost(dev->parent->parent);
        rphy = dev_to_rphy(dev);

        if (!shost->transportt)
                return 0;
        if (shost->transportt->host_attrs.ac.class !=
                        &sas_host_class.class)
                return 0;

        i = to_sas_internal(shost->transportt);
        return &i->end_dev_attr_cont.ac == cont &&
                rphy->identify.device_type == SAS_END_DEVICE;
}

static int sas_expander_match(struct attribute_container *cont,
                              struct device *dev)
{
        struct Scsi_Host *shost;
        struct sas_internal *i;
        struct sas_rphy *rphy;

        if (!scsi_is_sas_rphy(dev))
                return 0;
        shost = dev_to_shost(dev->parent->parent);
        rphy = dev_to_rphy(dev);

        if (!shost->transportt)
                return 0;
        if (shost->transportt->host_attrs.ac.class !=
                        &sas_host_class.class)
                return 0;

        i = to_sas_internal(shost->transportt);
        return &i->expander_attr_cont.ac == cont &&
                (rphy->identify.device_type == SAS_EDGE_EXPANDER_DEVICE ||
                 rphy->identify.device_type == SAS_FANOUT_EXPANDER_DEVICE);
}

static void sas_expander_release(struct device *dev)
{
        struct sas_rphy *rphy = dev_to_rphy(dev);
        struct sas_expander_device *edev = rphy_to_expander_device(rphy);

        if (rphy->q)
                blk_cleanup_queue(rphy->q);

        put_device(dev->parent);
        kfree(edev);
}

static void sas_end_device_release(struct device *dev)
{
        struct sas_rphy *rphy = dev_to_rphy(dev);
        struct sas_end_device *edev = rphy_to_end_device(rphy);

        if (rphy->q)
                blk_cleanup_queue(rphy->q);

        put_device(dev->parent);
        kfree(edev);
}

/**
 * sas_rphy_initialize - common rphy intialization
 * @rphy:       rphy to initialise
 *
 * Used by both sas_end_device_alloc() and sas_expander_alloc() to
 * initialise the common rphy component of each.
 */
static void sas_rphy_initialize(struct sas_rphy *rphy)
{
        INIT_LIST_HEAD(&rphy->list);
}

/**
 * sas_end_device_alloc - allocate an rphy for an end device
 * @parent: which port
 *
 * Allocates an SAS remote PHY structure, connected to @parent.
 *
 * Returns:
 *      SAS PHY allocated or %NULL if the allocation failed.
 */
struct sas_rphy *sas_end_device_alloc(struct sas_port *parent)
{
        struct Scsi_Host *shost = dev_to_shost(&parent->dev);
        struct sas_end_device *rdev;

        rdev = kzalloc(sizeof(*rdev), GFP_KERNEL);
        if (!rdev) {
                return NULL;
        }

        device_initialize(&rdev->rphy.dev);
        rdev->rphy.dev.parent = get_device(&parent->dev);
        rdev->rphy.dev.release = sas_end_device_release;
        if (scsi_is_sas_expander_device(parent->dev.parent)) {
                struct sas_rphy *rphy = dev_to_rphy(parent->dev.parent);
                dev_set_name(&rdev->rphy.dev, "end_device-%d:%d:%d",
                             shost->host_no, rphy->scsi_target_id,
                             parent->port_identifier);
        } else
                dev_set_name(&rdev->rphy.dev, "end_device-%d:%d",
                             shost->host_no, parent->port_identifier);
        rdev->rphy.identify.device_type = SAS_END_DEVICE;
        sas_rphy_initialize(&rdev->rphy);
        transport_setup_device(&rdev->rphy.dev);

        return &rdev->rphy;
}
EXPORT_SYMBOL(sas_end_device_alloc);

/**
 * sas_expander_alloc - allocate an rphy for an end device
 * @parent: which port
 * @type: SAS_EDGE_EXPANDER_DEVICE or SAS_FANOUT_EXPANDER_DEVICE
 *
 * Allocates an SAS remote PHY structure, connected to @parent.
 *
 * Returns:
 *      SAS PHY allocated or %NULL if the allocation failed.
 */
struct sas_rphy *sas_expander_alloc(struct sas_port *parent,
                                    enum sas_device_type type)
{
        struct Scsi_Host *shost = dev_to_shost(&parent->dev);
        struct sas_expander_device *rdev;
        struct sas_host_attrs *sas_host = to_sas_host_attrs(shost);

        BUG_ON(type != SAS_EDGE_EXPANDER_DEVICE &&
               type != SAS_FANOUT_EXPANDER_DEVICE);

        rdev = kzalloc(sizeof(*rdev), GFP_KERNEL);
        if (!rdev) {
                return NULL;
        }

        device_initialize(&rdev->rphy.dev);
        rdev->rphy.dev.parent = get_device(&parent->dev);
        rdev->rphy.dev.release = sas_expander_release;
        mutex_lock(&sas_host->lock);
        rdev->rphy.scsi_target_id = sas_host->next_expander_id++;
        mutex_unlock(&sas_host->lock);
        dev_set_name(&rdev->rphy.dev, "expander-%d:%d",
                     shost->host_no, rdev->rphy.scsi_target_id);
        rdev->rphy.identify.device_type = type;
        sas_rphy_initialize(&rdev->rphy);
        transport_setup_device(&rdev->rphy.dev);

        return &rdev->rphy;
}
EXPORT_SYMBOL(sas_expander_alloc);

/**
 * sas_rphy_add  -  add a SAS remote PHY to the device hierarchy
 * @rphy:       The remote PHY to be added
 *
 * Publishes a SAS remote PHY to the rest of the system.
 */
int sas_rphy_add(struct sas_rphy *rphy)
{
        struct sas_port *parent = dev_to_sas_port(rphy->dev.parent);
        struct Scsi_Host *shost = dev_to_shost(parent->dev.parent);
        struct sas_host_attrs *sas_host = to_sas_host_attrs(shost);
        struct sas_identify *identify = &rphy->identify;
        int error;

        if (parent->rphy)
                return -ENXIO;
        parent->rphy = rphy;

        error = device_add(&rphy->dev);
        if (error)
                return error;
        transport_add_device(&rphy->dev);
        transport_configure_device(&rphy->dev);
        if (sas_bsg_initialize(shost, rphy))
                printk("fail to a bsg device %s\n", dev_name(&rphy->dev));


        mutex_lock(&sas_host->lock);
        list_add_tail(&rphy->list, &sas_host->rphy_list);
        if (identify->device_type == SAS_END_DEVICE &&
            (identify->target_port_protocols &
             (SAS_PROTOCOL_SSP|SAS_PROTOCOL_STP|SAS_PROTOCOL_SATA)))
                rphy->scsi_target_id = sas_host->next_target_id++;
        else if (identify->device_type == SAS_END_DEVICE)
                rphy->scsi_target_id = -1;
        mutex_unlock(&sas_host->lock);

        if (identify->device_type == SAS_END_DEVICE &&
            rphy->scsi_target_id != -1) {
                int lun;

                if (identify->target_port_protocols & SAS_PROTOCOL_SSP)
                        lun = SCAN_WILD_CARD;
                else
                        lun = 0;

                scsi_scan_target(&rphy->dev, 0, rphy->scsi_target_id, lun,
                                 SCSI_SCAN_INITIAL);
        }

        return 0;
}
EXPORT_SYMBOL(sas_rphy_add);

/**
 * sas_rphy_free  -  free a SAS remote PHY
 * @rphy: SAS remote PHY to free
 *
 * Frees the specified SAS remote PHY.
 *
 * Note:
 *   This function must only be called on a remote
 *   PHY that has not successfully been added using
 *   sas_rphy_add() (or has been sas_rphy_remove()'d)
 */
void sas_rphy_free(struct sas_rphy *rphy)
{
        struct device *dev = &rphy->dev;
        struct Scsi_Host *shost = dev_to_shost(rphy->dev.parent->parent);
        struct sas_host_attrs *sas_host = to_sas_host_attrs(shost);

        mutex_lock(&sas_host->lock);
        list_del(&rphy->list);
        mutex_unlock(&sas_host->lock);

        transport_destroy_device(dev);

        put_device(dev);
}
EXPORT_SYMBOL(sas_rphy_free);

/**
 * sas_rphy_delete  -  remove and free SAS remote PHY
 * @rphy:       SAS remote PHY to remove and free
 *
 * Removes the specified SAS remote PHY and frees it.
 */
void
sas_rphy_delete(struct sas_rphy *rphy)
{
        sas_rphy_remove(rphy);
        sas_rphy_free(rphy);
}
EXPORT_SYMBOL(sas_rphy_delete);

/**
 * sas_rphy_unlink  -  unlink SAS remote PHY
 * @rphy:       SAS remote phy to unlink from its parent port
 *
 * Removes port reference to an rphy
 */
void sas_rphy_unlink(struct sas_rphy *rphy)
{
        struct sas_port *parent = dev_to_sas_port(rphy->dev.parent);

        parent->rphy = NULL;
}
EXPORT_SYMBOL(sas_rphy_unlink);

/**
 * sas_rphy_remove  -  remove SAS remote PHY
 * @rphy:       SAS remote phy to remove
 *
 * Removes the specified SAS remote PHY.
 */
void
sas_rphy_remove(struct sas_rphy *rphy)
{
        struct device *dev = &rphy->dev;

        switch (rphy->identify.device_type) {
        case SAS_END_DEVICE:
                scsi_remove_target(dev);
                break;
        case SAS_EDGE_EXPANDER_DEVICE:
        case SAS_FANOUT_EXPANDER_DEVICE:
                sas_remove_children(dev);
                break;
        default:
                break;
        }

        sas_rphy_unlink(rphy);
        sas_bsg_remove(NULL, rphy);
        transport_remove_device(dev);
        device_del(dev);
}
EXPORT_SYMBOL(sas_rphy_remove);

/**
 * scsi_is_sas_rphy  -  check if a struct device represents a SAS remote PHY
 * @dev:        device to check
 *
 * Returns:
 *      %1 if the device represents a SAS remote PHY, %0 else
 */
int scsi_is_sas_rphy(const struct device *dev)
{
        return dev->release == sas_end_device_release ||
                dev->release == sas_expander_release;
}
EXPORT_SYMBOL(scsi_is_sas_rphy);


/*
 * SCSI scan helper
 */

static int sas_user_scan(struct Scsi_Host *shost, uint channel,
                uint id, u64 lun)
{
        struct sas_host_attrs *sas_host = to_sas_host_attrs(shost);
        struct sas_rphy *rphy;

        mutex_lock(&sas_host->lock);
        list_for_each_entry(rphy, &sas_host->rphy_list, list) {
                if (rphy->identify.device_type != SAS_END_DEVICE ||
                    rphy->scsi_target_id == -1)
                        continue;

                if ((channel == SCAN_WILD_CARD || channel == 0) &&
                    (id == SCAN_WILD_CARD || id == rphy->scsi_target_id)) {
                        scsi_scan_target(&rphy->dev, 0, rphy->scsi_target_id,
                                         lun, SCSI_SCAN_MANUAL);
                }
        }
        mutex_unlock(&sas_host->lock);

        return 0;
}


/*
 * Setup / Teardown code
 */

#define SETUP_TEMPLATE(attrb, field, perm, test)                        \
        i->private_##attrb[count] = dev_attr_##field;           \
        i->private_##attrb[count].attr.mode = perm;                     \
        i->attrb[count] = &i->private_##attrb[count];                   \
        if (test)                                                       \
                count++

#define SETUP_TEMPLATE_RW(attrb, field, perm, test, ro_test, ro_perm)   \
        i->private_##attrb[count] = dev_attr_##field;           \
        i->private_##attrb[count].attr.mode = perm;                     \
        if (ro_test) {                                                  \
                i->private_##attrb[count].attr.mode = ro_perm;          \
                i->private_##attrb[count].store = NULL;                 \
        }                                                               \
        i->attrb[count] = &i->private_##attrb[count];                   \
        if (test)                                                       \
                count++

#define SETUP_RPORT_ATTRIBUTE(field)                                    \
        SETUP_TEMPLATE(rphy_attrs, field, S_IRUGO, 1)

#define SETUP_OPTIONAL_RPORT_ATTRIBUTE(field, func)                     \
        SETUP_TEMPLATE(rphy_attrs, field, S_IRUGO, i->f->func)

#define SETUP_PHY_ATTRIBUTE(field)                                      \
        SETUP_TEMPLATE(phy_attrs, field, S_IRUGO, 1)

#define SETUP_PHY_ATTRIBUTE_RW(field)                                   \
        SETUP_TEMPLATE_RW(phy_attrs, field, S_IRUGO | S_IWUSR, 1,       \
                        !i->f->set_phy_speed, S_IRUGO)

#define SETUP_OPTIONAL_PHY_ATTRIBUTE_RW(field, func)                    \
        SETUP_TEMPLATE_RW(phy_attrs, field, S_IRUGO | S_IWUSR, 1,       \
                          !i->f->func, S_IRUGO)

#define SETUP_PORT_ATTRIBUTE(field)                                     \
        SETUP_TEMPLATE(port_attrs, field, S_IRUGO, 1)

#define SETUP_OPTIONAL_PHY_ATTRIBUTE(field, func)                       \
        SETUP_TEMPLATE(phy_attrs, field, S_IRUGO, i->f->func)

#define SETUP_PHY_ATTRIBUTE_WRONLY(field)                               \
        SETUP_TEMPLATE(phy_attrs, field, S_IWUSR, 1)

#define SETUP_OPTIONAL_PHY_ATTRIBUTE_WRONLY(field, func)                \
        SETUP_TEMPLATE(phy_attrs, field, S_IWUSR, i->f->func)

#define SETUP_END_DEV_ATTRIBUTE(field)                                  \
        SETUP_TEMPLATE(end_dev_attrs, field, S_IRUGO, 1)

#define SETUP_EXPANDER_ATTRIBUTE(field)                                 \
        SETUP_TEMPLATE(expander_attrs, expander_##field, S_IRUGO, 1)

/**
 * sas_attach_transport  -  instantiate SAS transport template
 * @ft:         SAS transport class function template
 */
struct scsi_transport_template *
sas_attach_transport(struct sas_function_template *ft)
{
        struct sas_internal *i;
        int count;

        i = kzalloc(sizeof(struct sas_internal), GFP_KERNEL);
        if (!i)
                return NULL;

        i->t.user_scan = sas_user_scan;

        i->t.host_attrs.ac.attrs = &i->host_attrs[0];
        i->t.host_attrs.ac.class = &sas_host_class.class;
        i->t.host_attrs.ac.match = sas_host_match;
        transport_container_register(&i->t.host_attrs);
        i->t.host_size = sizeof(struct sas_host_attrs);

        i->phy_attr_cont.ac.class = &sas_phy_class.class;
        i->phy_attr_cont.ac.attrs = &i->phy_attrs[0];
        i->phy_attr_cont.ac.match = sas_phy_match;
        transport_container_register(&i->phy_attr_cont);

        i->port_attr_cont.ac.class = &sas_port_class.class;
        i->port_attr_cont.ac.attrs = &i->port_attrs[0];
        i->port_attr_cont.ac.match = sas_port_match;
        transport_container_register(&i->port_attr_cont);

        i->rphy_attr_cont.ac.class = &sas_rphy_class.class;
        i->rphy_attr_cont.ac.attrs = &i->rphy_attrs[0];
        i->rphy_attr_cont.ac.match = sas_rphy_match;
        transport_container_register(&i->rphy_attr_cont);

        i->end_dev_attr_cont.ac.class = &sas_end_dev_class.class;
        i->end_dev_attr_cont.ac.attrs = &i->end_dev_attrs[0];
        i->end_dev_attr_cont.ac.match = sas_end_dev_match;
        transport_container_register(&i->end_dev_attr_cont);

        i->expander_attr_cont.ac.class = &sas_expander_class.class;
        i->expander_attr_cont.ac.attrs = &i->expander_attrs[0];
        i->expander_attr_cont.ac.match = sas_expander_match;
        transport_container_register(&i->expander_attr_cont);

        i->f = ft;

        count = 0;
        SETUP_PHY_ATTRIBUTE(initiator_port_protocols);
        SETUP_PHY_ATTRIBUTE(target_port_protocols);
        SETUP_PHY_ATTRIBUTE(device_type);
        SETUP_PHY_ATTRIBUTE(sas_address);
        SETUP_PHY_ATTRIBUTE(phy_identifier);
        //SETUP_PHY_ATTRIBUTE(port_identifier);
        SETUP_PHY_ATTRIBUTE(negotiated_linkrate);
        SETUP_PHY_ATTRIBUTE(minimum_linkrate_hw);
        SETUP_PHY_ATTRIBUTE_RW(minimum_linkrate);
        SETUP_PHY_ATTRIBUTE(maximum_linkrate_hw);
        SETUP_PHY_ATTRIBUTE_RW(maximum_linkrate);

        SETUP_PHY_ATTRIBUTE(invalid_dword_count);
        SETUP_PHY_ATTRIBUTE(running_disparity_error_count);
        SETUP_PHY_ATTRIBUTE(loss_of_dword_sync_count);
        SETUP_PHY_ATTRIBUTE(phy_reset_problem_count);
        SETUP_OPTIONAL_PHY_ATTRIBUTE_WRONLY(link_reset, phy_reset);
        SETUP_OPTIONAL_PHY_ATTRIBUTE_WRONLY(hard_reset, phy_reset);
        SETUP_OPTIONAL_PHY_ATTRIBUTE_RW(enable, phy_enable);
        i->phy_attrs[count] = NULL;

        count = 0;
        SETUP_PORT_ATTRIBUTE(num_phys);
        i->port_attrs[count] = NULL;

        count = 0;
        SETUP_RPORT_ATTRIBUTE(rphy_initiator_port_protocols);
        SETUP_RPORT_ATTRIBUTE(rphy_target_port_protocols);
        SETUP_RPORT_ATTRIBUTE(rphy_device_type);
        SETUP_RPORT_ATTRIBUTE(rphy_sas_address);
        SETUP_RPORT_ATTRIBUTE(rphy_phy_identifier);
        SETUP_RPORT_ATTRIBUTE(rphy_scsi_target_id);
        SETUP_OPTIONAL_RPORT_ATTRIBUTE(rphy_enclosure_identifier,
                                       get_enclosure_identifier);
        SETUP_OPTIONAL_RPORT_ATTRIBUTE(rphy_bay_identifier,
                                       get_bay_identifier);
        i->rphy_attrs[count] = NULL;

        count = 0;
        SETUP_END_DEV_ATTRIBUTE(end_dev_ready_led_meaning);
        SETUP_END_DEV_ATTRIBUTE(end_dev_I_T_nexus_loss_timeout);
        SETUP_END_DEV_ATTRIBUTE(end_dev_initiator_response_timeout);
        SETUP_END_DEV_ATTRIBUTE(end_dev_tlr_supported);
        SETUP_END_DEV_ATTRIBUTE(end_dev_tlr_enabled);
        i->end_dev_attrs[count] = NULL;

        count = 0;
        SETUP_EXPANDER_ATTRIBUTE(vendor_id);
        SETUP_EXPANDER_ATTRIBUTE(product_id);
        SETUP_EXPANDER_ATTRIBUTE(product_rev);
        SETUP_EXPANDER_ATTRIBUTE(component_vendor_id);
        SETUP_EXPANDER_ATTRIBUTE(component_id);
        SETUP_EXPANDER_ATTRIBUTE(component_revision_id);
        SETUP_EXPANDER_ATTRIBUTE(level);
        i->expander_attrs[count] = NULL;

        return &i->t;
}
EXPORT_SYMBOL(sas_attach_transport);

/**
 * sas_release_transport  -  release SAS transport template instance
 * @t:          transport template instance
 */
void sas_release_transport(struct scsi_transport_template *t)
{
        struct sas_internal *i = to_sas_internal(t);

        transport_container_unregister(&i->t.host_attrs);
        transport_container_unregister(&i->phy_attr_cont);
        transport_container_unregister(&i->port_attr_cont);
        transport_container_unregister(&i->rphy_attr_cont);
        transport_container_unregister(&i->end_dev_attr_cont);
        transport_container_unregister(&i->expander_attr_cont);

        kfree(i);
}
EXPORT_SYMBOL(sas_release_transport);

static __init int sas_transport_init(void)
{
        int error;

        error = transport_class_register(&sas_host_class);
        if (error)
                goto out;
        error = transport_class_register(&sas_phy_class);
        if (error)
                goto out_unregister_transport;
        error = transport_class_register(&sas_port_class);
        if (error)
                goto out_unregister_phy;
        error = transport_class_register(&sas_rphy_class);
        if (error)
                goto out_unregister_port;
        error = transport_class_register(&sas_end_dev_class);
        if (error)
                goto out_unregister_rphy;
        error = transport_class_register(&sas_expander_class);
        if (error)
                goto out_unregister_end_dev;

        return 0;

 out_unregister_end_dev:
        transport_class_unregister(&sas_end_dev_class);
 out_unregister_rphy:
        transport_class_unregister(&sas_rphy_class);
 out_unregister_port:
        transport_class_unregister(&sas_port_class);
 out_unregister_phy:
        transport_class_unregister(&sas_phy_class);
 out_unregister_transport:
        transport_class_unregister(&sas_host_class);
 out:
        return error;

}

static void __exit sas_transport_exit(void)
{
        transport_class_unregister(&sas_host_class);
        transport_class_unregister(&sas_phy_class);
        transport_class_unregister(&sas_port_class);
        transport_class_unregister(&sas_rphy_class);
        transport_class_unregister(&sas_end_dev_class);
        transport_class_unregister(&sas_expander_class);
}

MODULE_AUTHOR("Christoph Hellwig");
MODULE_DESCRIPTION("SAS Transport Attributes");
MODULE_LICENSE("GPL");

module_init(sas_transport_init);
module_exit(sas_transport_exit);