scsi_transport_sas.c

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/*
 * 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 managment
 * 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_CLASS_DEVICE_ATTR(_prefix,_name,_mode,_show,_store) \
	struct class_device_attribute class_device_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_bitfield_name_search(linkspeed, sas_linkspeed_names)
sas_bitfield_name_set(linkspeed, sas_linkspeed_names)

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 (!blk_queue_plugged(q)) {
		req = elv_next_request(q);
		if (!req)
			break;

		blkdev_dequeue_request(req);

		spin_unlock_irq(q->queue_lock);

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

		spin_lock_irq(q->queue_lock);

		req->end_io(req, ret);
	}
}

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

	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->bus_id;
	} 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;
	}
	if (!q)
		return -ENOMEM;

	error = bsg_register_queue(q, dev, name);
	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;

	set_bit(QUEUE_FLAG_BIDI, &q->queue_flags);

	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);
	blk_cleanup_queue(q);
}

/*
 * SAS host attributes
 */

static int sas_host_setup(struct transport_container *tc, struct device *dev,
			  struct class_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 class_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 Phy attributes
 */

#define sas_phy_show_simple(field, name, format_string, cast)		\
static ssize_t								\
show_sas_phy_##name(struct class_device *cdev, char *buf)		\
{									\
	struct sas_phy *phy = transport_class_to_phy(cdev);		\
									\
	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 CLASS_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 class_device *cdev, char *buf)		\
{									\
	struct sas_phy *phy = transport_class_to_phy(cdev);		\
									\
	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 CLASS_DEVICE_ATTR(name, S_IRUGO, show_sas_phy_##name, NULL)

#define sas_phy_show_linkspeed(field)					\
static ssize_t								\
show_sas_phy_##field(struct class_device *cdev, char *buf)		\
{									\
	struct sas_phy *phy = transport_class_to_phy(cdev);		\
									\
	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 class_device *cdev, const char *buf,	\
		      size_t count)					\
{									\
	struct sas_phy *phy = transport_class_to_phy(cdev);		\
	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 CLASS_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 CLASS_DEVICE_ATTR(field, S_IRUGO, show_sas_phy_##field, NULL)


#define sas_phy_show_linkerror(field)					\
static ssize_t								\
show_sas_phy_##field(struct class_device *cdev, char *buf)		\
{									\
	struct sas_phy *phy = transport_class_to_phy(cdev);		\
	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 CLASS_DEVICE_ATTR(field, S_IRUGO, show_sas_phy_##field, NULL)


static ssize_t
show_sas_device_type(struct class_device *cdev, char *buf)
{