Merge branch 'generic-ipi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[linux-2.6] / drivers / ieee1394 / sbp2.c

/*
 * sbp2.c - SBP-2 protocol driver for IEEE-1394
 *
 * Copyright (C) 2000 James Goodwin, Filanet Corporation (www.filanet.com)
 * jamesg@filanet.com (JSG)
 *
 * Copyright (C) 2003 Ben Collins <bcollins@debian.org>
 *
 * 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 of the License, 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; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

/*
 * Brief Description:
 *
 * This driver implements the Serial Bus Protocol 2 (SBP-2) over IEEE-1394
 * under Linux. The SBP-2 driver is implemented as an IEEE-1394 high-level
 * driver. It also registers as a SCSI lower-level driver in order to accept
 * SCSI commands for transport using SBP-2.
 *
 * You may access any attached SBP-2 (usually storage devices) as regular
 * SCSI devices. E.g. mount /dev/sda1, fdisk, mkfs, etc..
 *
 * See http://www.t10.org/drafts.htm#sbp2 for the final draft of the SBP-2
 * specification and for where to purchase the official standard.
 *
 * TODO:
 *   - look into possible improvements of the SCSI error handlers
 *   - handle Unit_Characteristics.mgt_ORB_timeout and .ORB_size
 *   - handle Logical_Unit_Number.ordered
 *   - handle src == 1 in status blocks
 *   - reimplement the DMA mapping in absence of physical DMA so that
 *     bus_to_virt is no longer required
 *   - debug the handling of absent physical DMA
 *   - replace CONFIG_IEEE1394_SBP2_PHYS_DMA by automatic detection
 *     (this is easy but depends on the previous two TODO items)
 *   - make the parameter serialize_io configurable per device
 *   - move all requests to fetch agent registers into non-atomic context,
 *     replace all usages of sbp2util_node_write_no_wait by true transactions
 * Grep for inline FIXME comments below.
 */

#include <linux/blkdev.h>
#include <linux/compiler.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/gfp.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/stringify.h>
#include <linux/types.h>
#include <linux/wait.h>
#include <linux/workqueue.h>
#include <linux/scatterlist.h>

#include <asm/byteorder.h>
#include <asm/errno.h>
#include <asm/param.h>
#include <asm/system.h>
#include <asm/types.h>

#ifdef CONFIG_IEEE1394_SBP2_PHYS_DMA
#include <asm/io.h> /* for bus_to_virt */
#endif

#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_dbg.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>

#include "csr1212.h"
#include "highlevel.h"
#include "hosts.h"
#include "ieee1394.h"
#include "ieee1394_core.h"
#include "ieee1394_hotplug.h"
#include "ieee1394_transactions.h"
#include "ieee1394_types.h"
#include "nodemgr.h"
#include "sbp2.h"

/*
 * Module load parameter definitions
 */

/*
 * Change max_speed on module load if you have a bad IEEE-1394
 * controller that has trouble running 2KB packets at 400mb.
 *
 * NOTE: On certain OHCI parts I have seen short packets on async transmit
 * (probably due to PCI latency/throughput issues with the part). You can
 * bump down the speed if you are running into problems.
 */
static int sbp2_max_speed = IEEE1394_SPEED_MAX;
module_param_named(max_speed, sbp2_max_speed, int, 0644);
MODULE_PARM_DESC(max_speed, "Force max speed "
                 "(3 = 800Mb/s, 2 = 400Mb/s, 1 = 200Mb/s, 0 = 100Mb/s)");

/*
 * Set serialize_io to 0 or N to use dynamically appended lists of command ORBs.
 * This is and always has been buggy in multiple subtle ways. See above TODOs.
 */
static int sbp2_serialize_io = 1;
module_param_named(serialize_io, sbp2_serialize_io, bool, 0444);
MODULE_PARM_DESC(serialize_io, "Serialize requests coming from SCSI drivers "
                 "(default = Y, faster but buggy = N)");

/*
 * Adjust max_sectors if you'd like to influence how many sectors each SCSI
 * command can transfer at most. Please note that some older SBP-2 bridge
 * chips are broken for transfers greater or equal to 128KB, therefore
 * max_sectors used to be a safe 255 sectors for many years. We now have a
 * default of 0 here which means that we let the SCSI stack choose a limit.
 *
 * The SBP2_WORKAROUND_128K_MAX_TRANS flag, if set either in the workarounds
 * module parameter or in the sbp2_workarounds_table[], will override the
 * value of max_sectors. We should use sbp2_workarounds_table[] to cover any
 * bridge chip which becomes known to need the 255 sectors limit.
 */
static int sbp2_max_sectors;
module_param_named(max_sectors, sbp2_max_sectors, int, 0444);
MODULE_PARM_DESC(max_sectors, "Change max sectors per I/O supported "
                 "(default = 0 = use SCSI stack's default)");

/*
 * Exclusive login to sbp2 device? In most cases, the sbp2 driver should
 * do an exclusive login, as it's generally unsafe to have two hosts
 * talking to a single sbp2 device at the same time (filesystem coherency,
 * etc.). If you're running an sbp2 device that supports multiple logins,
 * and you're either running read-only filesystems or some sort of special
 * filesystem supporting multiple hosts, e.g. OpenGFS, Oracle Cluster
 * File System, or Lustre, then set exclusive_login to zero.
 *
 * So far only bridges from Oxford Semiconductor are known to support
 * concurrent logins. Depending on firmware, four or two concurrent logins
 * are possible on OXFW911 and newer Oxsemi bridges.
 */
static int sbp2_exclusive_login = 1;
module_param_named(exclusive_login, sbp2_exclusive_login, bool, 0644);
MODULE_PARM_DESC(exclusive_login, "Exclusive login to sbp2 device "
                 "(default = Y, use N for concurrent initiators)");

/*
 * If any of the following workarounds is required for your device to work,
 * please submit the kernel messages logged by sbp2 to the linux1394-devel
 * mailing list.
 *
 * - 128kB max transfer
 *   Limit transfer size. Necessary for some old bridges.
 *
 * - 36 byte inquiry
 *   When scsi_mod probes the device, let the inquiry command look like that
 *   from MS Windows.
 *
 * - skip mode page 8
 *   Suppress sending of mode_sense for mode page 8 if the device pretends to
 *   support the SCSI Primary Block commands instead of Reduced Block Commands.
 *
 * - fix capacity
 *   Tell sd_mod to correct the last sector number reported by read_capacity.
 *   Avoids access beyond actual disk limits on devices with an off-by-one bug.
 *   Don't use this with devices which don't have this bug.
 *
 * - delay inquiry
 *   Wait extra SBP2_INQUIRY_DELAY seconds after login before SCSI inquiry.
 *
 * - power condition
 *   Set the power condition field in the START STOP UNIT commands sent by
 *   sd_mod on suspend, resume, and shutdown (if manage_start_stop is on).
 *   Some disks need this to spin down or to resume properly.
 *
 * - override internal blacklist
 *   Instead of adding to the built-in blacklist, use only the workarounds
 *   specified in the module load parameter.
 *   Useful if a blacklist entry interfered with a non-broken device.
 */
static int sbp2_default_workarounds;
module_param_named(workarounds, sbp2_default_workarounds, int, 0644);
MODULE_PARM_DESC(workarounds, "Work around device bugs (default = 0"
        ", 128kB max transfer = " __stringify(SBP2_WORKAROUND_128K_MAX_TRANS)
        ", 36 byte inquiry = "    __stringify(SBP2_WORKAROUND_INQUIRY_36)
        ", skip mode page 8 = "   __stringify(SBP2_WORKAROUND_MODE_SENSE_8)
        ", fix capacity = "       __stringify(SBP2_WORKAROUND_FIX_CAPACITY)
        ", delay inquiry = "      __stringify(SBP2_WORKAROUND_DELAY_INQUIRY)
        ", set power condition in start stop unit = "
                                  __stringify(SBP2_WORKAROUND_POWER_CONDITION)
        ", override internal blacklist = " __stringify(SBP2_WORKAROUND_OVERRIDE)
        ", or a combination)");

/*
 * This influences the format of the sysfs attribute
 * /sys/bus/scsi/devices/.../ieee1394_id.
 *
 * The default format is like in older kernels:  %016Lx:%d:%d
 * It contains the target's EUI-64, a number given to the logical unit by
 * the ieee1394 driver's nodemgr (starting at 0), and the LUN.
 *
 * The long format is:  %016Lx:%06x:%04x
 * It contains the target's EUI-64, the unit directory's directory_ID as per
 * IEEE 1212 clause 7.7.19, and the LUN.  This format comes closest to the
 * format of SBP(-3) target port and logical unit identifier as per SAM (SCSI
 * Architecture Model) rev.2 to 4 annex A.  Therefore and because it is
 * independent of the implementation of the ieee1394 nodemgr, the longer format
 * is recommended for future use.
 */
static int sbp2_long_sysfs_ieee1394_id;
module_param_named(long_ieee1394_id, sbp2_long_sysfs_ieee1394_id, bool, 0644);
MODULE_PARM_DESC(long_ieee1394_id, "8+3+2 bytes format of ieee1394_id in sysfs "
                 "(default = backwards-compatible = N, SAM-conforming = Y)");


#define SBP2_INFO(fmt, args...) HPSB_INFO("sbp2: "fmt, ## args)
#define SBP2_ERR(fmt, args...)  HPSB_ERR("sbp2: "fmt, ## args)

/*
 * Globals
 */
static void sbp2scsi_complete_all_commands(struct sbp2_lu *, u32);
static void sbp2scsi_complete_command(struct sbp2_lu *, u32, struct scsi_cmnd *,
                                      void (*)(struct scsi_cmnd *));
static struct sbp2_lu *sbp2_alloc_device(struct unit_directory *);
static int sbp2_start_device(struct sbp2_lu *);
static void sbp2_remove_device(struct sbp2_lu *);
static int sbp2_login_device(struct sbp2_lu *);
static int sbp2_reconnect_device(struct sbp2_lu *);
static int sbp2_logout_device(struct sbp2_lu *);
static void sbp2_host_reset(struct hpsb_host *);
static int sbp2_handle_status_write(struct hpsb_host *, int, int, quadlet_t *,
                                    u64, size_t, u16);
static int sbp2_agent_reset(struct sbp2_lu *, int);
static void sbp2_parse_unit_directory(struct sbp2_lu *,
                                      struct unit_directory *);
static int sbp2_set_busy_timeout(struct sbp2_lu *);
static int sbp2_max_speed_and_size(struct sbp2_lu *);


static const u8 sbp2_speedto_max_payload[] = { 0x7, 0x8, 0x9, 0xA, 0xB, 0xC };

static DEFINE_RWLOCK(sbp2_hi_logical_units_lock);

static struct hpsb_highlevel sbp2_highlevel = {
        .name           = SBP2_DEVICE_NAME,
        .host_reset     = sbp2_host_reset,
};

static struct hpsb_address_ops sbp2_ops = {
        .write          = sbp2_handle_status_write
};

#ifdef CONFIG_IEEE1394_SBP2_PHYS_DMA
static int sbp2_handle_physdma_write(struct hpsb_host *, int, int, quadlet_t *,
                                     u64, size_t, u16);
static int sbp2_handle_physdma_read(struct hpsb_host *, int, quadlet_t *, u64,
                                    size_t, u16);

static struct hpsb_address_ops sbp2_physdma_ops = {
        .read           = sbp2_handle_physdma_read,
        .write          = sbp2_handle_physdma_write,
};
#endif


/*
 * Interface to driver core and IEEE 1394 core
 */
static struct ieee1394_device_id sbp2_id_table[] = {
        {
         .match_flags   = IEEE1394_MATCH_SPECIFIER_ID | IEEE1394_MATCH_VERSION,
         .specifier_id  = SBP2_UNIT_SPEC_ID_ENTRY & 0xffffff,
         .version       = SBP2_SW_VERSION_ENTRY & 0xffffff},
        {}
};
MODULE_DEVICE_TABLE(ieee1394, sbp2_id_table);

static int sbp2_probe(struct device *);
static int sbp2_remove(struct device *);
static int sbp2_update(struct unit_directory *);

static struct hpsb_protocol_driver sbp2_driver = {
        .name           = SBP2_DEVICE_NAME,
        .id_table       = sbp2_id_table,
        .update         = sbp2_update,
        .driver         = {
                .probe          = sbp2_probe,
                .remove         = sbp2_remove,
        },
};


/*
 * Interface to SCSI core
 */
static int sbp2scsi_queuecommand(struct scsi_cmnd *,
                                 void (*)(struct scsi_cmnd *));
static int sbp2scsi_abort(struct scsi_cmnd *);
static int sbp2scsi_reset(struct scsi_cmnd *);
static int sbp2scsi_slave_alloc(struct scsi_device *);
static int sbp2scsi_slave_configure(struct scsi_device *);
static void sbp2scsi_slave_destroy(struct scsi_device *);
static ssize_t sbp2_sysfs_ieee1394_id_show(struct device *,
                                           struct device_attribute *, char *);

static DEVICE_ATTR(ieee1394_id, S_IRUGO, sbp2_sysfs_ieee1394_id_show, NULL);

static struct device_attribute *sbp2_sysfs_sdev_attrs[] = {
        &dev_attr_ieee1394_id,
        NULL
};

static struct scsi_host_template sbp2_shost_template = {
        .module                  = THIS_MODULE,
        .name                    = "SBP-2 IEEE-1394",
        .proc_name               = SBP2_DEVICE_NAME,
        .queuecommand            = sbp2scsi_queuecommand,
        .eh_abort_handler        = sbp2scsi_abort,
        .eh_device_reset_handler = sbp2scsi_reset,
        .slave_alloc             = sbp2scsi_slave_alloc,
        .slave_configure         = sbp2scsi_slave_configure,
        .slave_destroy           = sbp2scsi_slave_destroy,
        .this_id                 = -1,
        .sg_tablesize            = SG_ALL,
        .use_clustering          = ENABLE_CLUSTERING,
        .cmd_per_lun             = SBP2_MAX_CMDS,
        .can_queue               = SBP2_MAX_CMDS,
        .sdev_attrs              = sbp2_sysfs_sdev_attrs,
};

/* for match-all entries in sbp2_workarounds_table */
#define SBP2_ROM_VALUE_WILDCARD 0x1000000

/*
 * List of devices with known bugs.
 *
 * The firmware_revision field, masked with 0xffff00, is the best indicator
 * for the type of bridge chip of a device.  It yields a few false positives
 * but this did not break correctly behaving devices so far.
 */
static const struct {
        u32 firmware_revision;
        u32 model_id;
        unsigned workarounds;
} sbp2_workarounds_table[] = {
        /* DViCO Momobay CX-1 with TSB42AA9 bridge */ {
                .firmware_revision      = 0x002800,
                .model_id               = 0x001010,
                .workarounds            = SBP2_WORKAROUND_INQUIRY_36 |
                                          SBP2_WORKAROUND_MODE_SENSE_8 |
                                          SBP2_WORKAROUND_POWER_CONDITION,
        },
        /* DViCO Momobay FX-3A with TSB42AA9A bridge */ {
                .firmware_revision      = 0x002800,
                .model_id               = 0x000000,
                .workarounds            = SBP2_WORKAROUND_DELAY_INQUIRY |
                                          SBP2_WORKAROUND_POWER_CONDITION,
        },
        /* Initio bridges, actually only needed for some older ones */ {
                .firmware_revision      = 0x000200,
                .model_id               = SBP2_ROM_VALUE_WILDCARD,
                .workarounds            = SBP2_WORKAROUND_INQUIRY_36,
        },
        /* PL-3507 bridge with Prolific firmware */ {
                .firmware_revision      = 0x012800,
                .model_id               = SBP2_ROM_VALUE_WILDCARD,
                .workarounds            = SBP2_WORKAROUND_POWER_CONDITION,
        },
        /* Symbios bridge */ {
                .firmware_revision      = 0xa0b800,
                .model_id               = SBP2_ROM_VALUE_WILDCARD,
                .workarounds            = SBP2_WORKAROUND_128K_MAX_TRANS,
        },
        /* Datafab MD2-FW2 with Symbios/LSILogic SYM13FW500 bridge */ {
                .firmware_revision      = 0x002600,
                .model_id               = SBP2_ROM_VALUE_WILDCARD,
                .workarounds            = SBP2_WORKAROUND_128K_MAX_TRANS,
        },
        /* iPod 4th generation */ {
                .firmware_revision      = 0x0a2700,
                .model_id               = 0x000021,
                .workarounds            = SBP2_WORKAROUND_FIX_CAPACITY,
        },
        /* iPod mini */ {
                .firmware_revision      = 0x0a2700,
                .model_id               = 0x000023,
                .workarounds            = SBP2_WORKAROUND_FIX_CAPACITY,
        },
        /* iPod Photo */ {
                .firmware_revision      = 0x0a2700,
                .model_id               = 0x00007e,
                .workarounds            = SBP2_WORKAROUND_FIX_CAPACITY,
        }
};

/**************************************
 * General utility functions
 **************************************/

#ifndef __BIG_ENDIAN
/*
 * Converts a buffer from be32 to cpu byte ordering. Length is in bytes.
 */
static inline void sbp2util_be32_to_cpu_buffer(void *buffer, int length)
{
        u32 *temp = buffer;

        for (length = (length >> 2); length--; )
                temp[length] = be32_to_cpu(temp[length]);
}

/*
 * Converts a buffer from cpu to be32 byte ordering. Length is in bytes.
 */
static inline void sbp2util_cpu_to_be32_buffer(void *buffer, int length)
{
        u32 *temp = buffer;

        for (length = (length >> 2); length--; )
                temp[length] = cpu_to_be32(temp[length]);
}
#else /* BIG_ENDIAN */
/* Why waste the cpu cycles? */
#define sbp2util_be32_to_cpu_buffer(x,y) do {} while (0)
#define sbp2util_cpu_to_be32_buffer(x,y) do {} while (0)
#endif

static DECLARE_WAIT_QUEUE_HEAD(sbp2_access_wq);

/*
 * Waits for completion of an SBP-2 access request.
 * Returns nonzero if timed out or prematurely interrupted.
 */
static int sbp2util_access_timeout(struct sbp2_lu *lu, int timeout)
{
        long leftover;

        leftover = wait_event_interruptible_timeout(
                        sbp2_access_wq, lu->access_complete, timeout);
        lu->access_complete = 0;
        return leftover <= 0;
}

static void sbp2_free_packet(void *packet)
{
        hpsb_free_tlabel(packet);
        hpsb_free_packet(packet);
}

/*
 * This is much like hpsb_node_write(), except it ignores the response
 * subaction and returns immediately. Can be used from atomic context.
 */
static int sbp2util_node_write_no_wait(struct node_entry *ne, u64 addr,
                                       quadlet_t *buf, size_t len)
{
        struct hpsb_packet *packet;

        packet = hpsb_make_writepacket(ne->host, ne->nodeid, addr, buf, len);
        if (!packet)
                return -ENOMEM;

        hpsb_set_packet_complete_task(packet, sbp2_free_packet, packet);
        hpsb_node_fill_packet(ne, packet);
        if (hpsb_send_packet(packet) < 0) {
                sbp2_free_packet(packet);
                return -EIO;
        }
        return 0;
}

static void sbp2util_notify_fetch_agent(struct sbp2_lu *lu, u64 offset,
                                        quadlet_t *data, size_t len)
{
        /* There is a small window after a bus reset within which the node
         * entry's generation is current but the reconnect wasn't completed. */
        if (unlikely(atomic_read(&lu->state) == SBP2LU_STATE_IN_RESET))
                return;

        if (hpsb_node_write(lu->ne, lu->command_block_agent_addr + offset,
                            data, len))
                SBP2_ERR("sbp2util_notify_fetch_agent failed.");

        /* Now accept new SCSI commands, unless a bus reset happended during
         * hpsb_node_write. */
        if (likely(atomic_read(&lu->state) != SBP2LU_STATE_IN_RESET))
                scsi_unblock_requests(lu->shost);
}

static void sbp2util_write_orb_pointer(struct work_struct *work)
{
        struct sbp2_lu *lu = container_of(work, struct sbp2_lu, protocol_work);
        quadlet_t data[2];

        data[0] = ORB_SET_NODE_ID(lu->hi->host->node_id);
        data[1] = lu->last_orb_dma;
        sbp2util_cpu_to_be32_buffer(data, 8);
        sbp2util_notify_fetch_agent(lu, SBP2_ORB_POINTER_OFFSET, data, 8);
}

static void sbp2util_write_doorbell(struct work_struct *work)
{
        struct sbp2_lu *lu = container_of(work, struct sbp2_lu, protocol_work);

        sbp2util_notify_fetch_agent(lu, SBP2_DOORBELL_OFFSET, NULL, 4);
}

static int sbp2util_create_command_orb_pool(struct sbp2_lu *lu)
{
        struct sbp2_fwhost_info *hi = lu->hi;
        struct sbp2_command_info *cmd;
        int i, orbs = sbp2_serialize_io ? 2 : SBP2_MAX_CMDS;

        for (i = 0; i < orbs; i++) {
                cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
                if (!cmd)
                        return -ENOMEM;
                cmd->command_orb_dma = dma_map_single(hi->host->device.parent,
                                                &cmd->command_orb,
                                                sizeof(struct sbp2_command_orb),
                                                DMA_TO_DEVICE);
                cmd->sge_dma = dma_map_single(hi->host->device.parent,
                                        &cmd->scatter_gather_element,
                                        sizeof(cmd->scatter_gather_element),
                                        DMA_TO_DEVICE);
                INIT_LIST_HEAD(&cmd->list);
                list_add_tail(&cmd->list, &lu->cmd_orb_completed);
        }
        return 0;
}

static void sbp2util_remove_command_orb_pool(struct sbp2_lu *lu,
                                             struct hpsb_host *host)
{
        struct list_head *lh, *next;
        struct sbp2_command_info *cmd;
        unsigned long flags;

        spin_lock_irqsave(&lu->cmd_orb_lock, flags);
        if (!list_empty(&lu->cmd_orb_completed))
                list_for_each_safe(lh, next, &lu->cmd_orb_completed) {
                        cmd = list_entry(lh, struct sbp2_command_info, list);
                        dma_unmap_single(host->device.parent,
                                         cmd->command_orb_dma,
                                         sizeof(struct sbp2_command_orb),
                                         DMA_TO_DEVICE);
                        dma_unmap_single(host->device.parent, cmd->sge_dma,
                                         sizeof(cmd->scatter_gather_element),
                                         DMA_TO_DEVICE);
                        kfree(cmd);
                }
        spin_unlock_irqrestore(&lu->cmd_orb_lock, flags);
        return;
}

/*
 * Finds the sbp2_command for a given outstanding command ORB.
 * Only looks at the in-use list.
 */
static struct sbp2_command_info *sbp2util_find_command_for_orb(
                                struct sbp2_lu *lu, dma_addr_t orb)
{
        struct sbp2_command_info *cmd;
        unsigned long flags;

        spin_lock_irqsave(&lu->cmd_orb_lock, flags);
        if (!list_empty(&lu->cmd_orb_inuse))
                list_for_each_entry(cmd, &lu->cmd_orb_inuse, list)
                        if (cmd->command_orb_dma == orb) {
                                spin_unlock_irqrestore(
                                                &lu->cmd_orb_lock, flags);
                                return cmd;
                        }
        spin_unlock_irqrestore(&lu->cmd_orb_lock, flags);
        return NULL;
}

/*
 * Finds the sbp2_command for a given outstanding SCpnt.
 * Only looks at the in-use list.
 * Must be called with lu->cmd_orb_lock held.
 */
static struct sbp2_command_info *sbp2util_find_command_for_SCpnt(
                                struct sbp2_lu *lu, void *SCpnt)
{
        struct sbp2_command_info *cmd;

        if (!list_empty(&lu->cmd_orb_inuse))
                list_for_each_entry(cmd, &lu->cmd_orb_inuse, list)
                        if (cmd->Current_SCpnt == SCpnt)
                                return cmd;
        return NULL;
}

static struct sbp2_command_info *sbp2util_allocate_command_orb(
                                struct sbp2_lu *lu,
                                struct scsi_cmnd *Current_SCpnt,
                                void (*Current_done)(struct scsi_cmnd *))
{
        struct list_head *lh;
        struct sbp2_command_info *cmd = NULL;
        unsigned long flags;

        spin_lock_irqsave(&lu->cmd_orb_lock, flags);
        if (!list_empty(&lu->cmd_orb_completed)) {
                lh = lu->cmd_orb_completed.next;
                list_del(lh);
                cmd = list_entry(lh, struct sbp2_command_info, list);
                cmd->Current_done = Current_done;
                cmd->Current_SCpnt = Current_SCpnt;
                list_add_tail(&cmd->list, &lu->cmd_orb_inuse);
        } else
                SBP2_ERR("%s: no orbs available", __func__);
        spin_unlock_irqrestore(&lu->cmd_orb_lock, flags);
        return cmd;
}

/*
 * Unmaps the DMAs of a command and moves the command to the completed ORB list.
 * Must be called with lu->cmd_orb_lock held.
 */
static void sbp2util_mark_command_completed(struct sbp2_lu *lu,
                                            struct sbp2_command_info *cmd)
{
        struct hpsb_host *host = lu->ud->ne->host;

        if (cmd->cmd_dma) {
                if (cmd->dma_type == CMD_DMA_SINGLE)
                        dma_unmap_single(host->device.parent, cmd->cmd_dma,
                                         cmd->dma_size, cmd->dma_dir);
                else if (cmd->dma_type == CMD_DMA_PAGE)
                        dma_unmap_page(host->device.parent, cmd->cmd_dma,
                                       cmd->dma_size, cmd->dma_dir);
                /* XXX: Check for CMD_DMA_NONE bug */
                cmd->dma_type = CMD_DMA_NONE;
                cmd->cmd_dma = 0;
        }
        if (cmd->sge_buffer) {
                dma_unmap_sg(host->device.parent, cmd->sge_buffer,
                             cmd->dma_size, cmd->dma_dir);
                cmd->sge_buffer = NULL;
        }
        list_move_tail(&cmd->list, &lu->cmd_orb_completed);
}

/*
 * Is lu valid? Is the 1394 node still present?
 */
static inline int sbp2util_node_is_available(struct sbp2_lu *lu)
{
        return lu && lu->ne && !lu->ne->in_limbo;
}

/*********************************************
 * IEEE-1394 core driver stack related section
 *********************************************/

static int sbp2_probe(struct device *dev)
{
        struct unit_directory *ud;
        struct sbp2_lu *lu;

        ud = container_of(dev, struct unit_directory, device);

        /* Don't probe UD's that have the LUN flag. We'll probe the LUN(s)
         * instead. */
        if (ud->flags & UNIT_DIRECTORY_HAS_LUN_DIRECTORY)
                return -ENODEV;

        lu = sbp2_alloc_device(ud);
        if (!lu)
                return -ENOMEM;

        sbp2_parse_unit_directory(lu, ud);
        return sbp2_start_device(lu);
}

static int sbp2_remove(struct device *dev)
{
        struct unit_directory *ud;
        struct sbp2_lu *lu;
        struct scsi_device *sdev;

        ud = container_of(dev, struct unit_directory, device);
        lu = ud->device.driver_data;
        if (!lu)
                return 0;

        if (lu->shost) {
                /* Get rid of enqueued commands if there is no chance to
                 * send them. */
                if (!sbp2util_node_is_available(lu))
                        sbp2scsi_complete_all_commands(lu, DID_NO_CONNECT);
                /* scsi_remove_device() may trigger shutdown functions of SCSI
                 * highlevel drivers which would deadlock if blocked. */
                atomic_set(&lu->state, SBP2LU_STATE_IN_SHUTDOWN);
                scsi_unblock_requests(lu->shost);
        }
        sdev = lu->sdev;
        if (sdev) {
                lu->sdev = NULL;
                scsi_remove_device(sdev);
        }

        sbp2_logout_device(lu);
        sbp2_remove_device(lu);

        return 0;
}

static int sbp2_update(struct unit_directory *ud)
{
        struct sbp2_lu *lu = ud->device.driver_data;

        if (sbp2_reconnect_device(lu)) {
                /* Reconnect has failed. Perhaps we didn't reconnect fast
                 * enough. Try a regular login, but first log out just in
                 * case of any weirdness. */
                sbp2_logout_device(lu);

                if (sbp2_login_device(lu)) {
                        /* Login failed too, just fail, and the backend
                         * will call our sbp2_remove for us */
                        SBP2_ERR("Failed to reconnect to sbp2 device!");
                        return -EBUSY;
                }
        }

        sbp2_set_busy_timeout(lu);
        sbp2_agent_reset(lu, 1);
        sbp2_max_speed_and_size(lu);

        /* Complete any pending commands with busy (so they get retried)
         * and remove them from our queue. */
        sbp2scsi_complete_all_commands(lu, DID_BUS_BUSY);

        /* Accept new commands unless there was another bus reset in the
         * meantime. */
        if (hpsb_node_entry_valid(lu->ne)) {
                atomic_set(&lu->state, SBP2LU_STATE_RUNNING);
                scsi_unblock_requests(lu->shost);
        }
        return 0;
}

static struct sbp2_lu *sbp2_alloc_device(struct unit_directory *ud)
{
        struct sbp2_fwhost_info *hi;
        struct Scsi_Host *shost = NULL;
        struct sbp2_lu *lu = NULL;
        unsigned long flags;

        lu = kzalloc(sizeof(*lu), GFP_KERNEL);
        if (!lu) {
                SBP2_ERR("failed to create lu");
                goto failed_alloc;
        }

        lu->ne = ud->ne;
        lu->ud = ud;
        lu->speed_code = IEEE1394_SPEED_100;
        lu->max_payload_size = sbp2_speedto_max_payload[IEEE1394_SPEED_100];
        lu->status_fifo_addr = CSR1212_INVALID_ADDR_SPACE;
        INIT_LIST_HEAD(&lu->cmd_orb_inuse);
        INIT_LIST_HEAD(&lu->cmd_orb_completed);
        INIT_LIST_HEAD(&lu->lu_list);
        spin_lock_init(&lu->cmd_orb_lock);
        atomic_set(&lu->state, SBP2LU_STATE_RUNNING);
        INIT_WORK(&lu->protocol_work, NULL);

        ud->device.driver_data = lu;

        hi = hpsb_get_hostinfo(&sbp2_highlevel, ud->ne->host);
        if (!hi) {
                hi = hpsb_create_hostinfo(&sbp2_highlevel, ud->ne->host,
                                          sizeof(*hi));
                if (!hi) {
                        SBP2_ERR("failed to allocate hostinfo");
                        goto failed_alloc;
                }
                hi->host = ud->ne->host;
                INIT_LIST_HEAD(&hi->logical_units);

#ifdef CONFIG_IEEE1394_SBP2_PHYS_DMA
                /* Handle data movement if physical dma is not
                 * enabled or not supported on host controller */
                if (!hpsb_register_addrspace(&sbp2_highlevel, ud->ne->host,
                                             &sbp2_physdma_ops,
                                             0x0ULL, 0xfffffffcULL)) {
                        SBP2_ERR("failed to register lower 4GB address range");
                        goto failed_alloc;
                }
#endif
        }

        /* Prevent unloading of the 1394 host */
        if (!try_module_get(hi->host->driver->owner)) {
                SBP2_ERR("failed to get a reference on 1394 host driver");
                goto failed_alloc;
        }

        lu->hi = hi;

        write_lock_irqsave(&sbp2_hi_logical_units_lock, flags);
        list_add_tail(&lu->lu_list, &hi->logical_units);
        write_unlock_irqrestore(&sbp2_hi_logical_units_lock, flags);

        /* Register the status FIFO address range. We could use the same FIFO
         * for targets at different nodes. However we need different FIFOs per
         * target in order to support multi-unit devices.
         * The FIFO is located out of the local host controller's physical range
         * but, if possible, within the posted write area. Status writes will
         * then be performed as unified transactions. This slightly reduces
         * bandwidth usage, and some Prolific based devices seem to require it.
         */
        lu->status_fifo_addr = hpsb_allocate_and_register_addrspace(
                        &sbp2_highlevel, ud->ne->host, &sbp2_ops,
                        sizeof(struct sbp2_status_block), sizeof(quadlet_t),
                        ud->ne->host->low_addr_space, CSR1212_ALL_SPACE_END);
        if (lu->status_fifo_addr == CSR1212_INVALID_ADDR_SPACE) {
                SBP2_ERR("failed to allocate status FIFO address range");
                goto failed_alloc;
        }

        shost = scsi_host_alloc(&sbp2_shost_template, sizeof(unsigned long));
        if (!shost) {
                SBP2_ERR("failed to register scsi host");
                goto failed_alloc;
        }

        shost->hostdata[0] = (unsigned long)lu;

        if (!scsi_add_host(shost, &ud->device)) {
                lu->shost = shost;
                return lu;
        }

        SBP2_ERR("failed to add scsi host");
        scsi_host_put(shost);

failed_alloc:
        sbp2_remove_device(lu);
        return NULL;
}

static void sbp2_host_reset(struct hpsb_host *host)
{
        struct sbp2_fwhost_info *hi;
        struct sbp2_lu *lu;
        unsigned long flags;

        hi = hpsb_get_hostinfo(&sbp2_highlevel, host);
        if (!hi)
                return;

        read_lock_irqsave(&sbp2_hi_logical_units_lock, flags);
        list_for_each_entry(lu, &hi->logical_units, lu_list)
                if (likely(atomic_read(&lu->state) !=
                           SBP2LU_STATE_IN_SHUTDOWN)) {
                        atomic_set(&lu->state, SBP2LU_STATE_IN_RESET);
                        scsi_block_requests(lu->shost);
                }
        read_unlock_irqrestore(&sbp2_hi_logical_units_lock, flags);
}

static int sbp2_start_device(struct sbp2_lu *lu)
{
        struct sbp2_fwhost_info *hi = lu->hi;
        int error;

        lu->login_response = dma_alloc_coherent(hi->host->device.parent,
                                     sizeof(struct sbp2_login_response),
                                     &lu->login_response_dma, GFP_KERNEL);
        if (!lu->login_response)
                goto alloc_fail;

        lu->query_logins_orb = dma_alloc_coherent(hi->host->device.parent,
                                     sizeof(struct sbp2_query_logins_orb),
                                     &lu->query_logins_orb_dma, GFP_KERNEL);
        if (!lu->query_logins_orb)
                goto alloc_fail;

        lu->query_logins_response = dma_alloc_coherent(hi->host->device.parent,
                                     sizeof(struct sbp2_query_logins_response),
                                     &lu->query_logins_response_dma, GFP_KERNEL);
        if (!lu->query_logins_response)
                goto alloc_fail;

        lu->reconnect_orb = dma_alloc_coherent(hi->host->device.parent,
                                     sizeof(struct sbp2_reconnect_orb),
                                     &lu->reconnect_orb_dma, GFP_KERNEL);
        if (!lu->reconnect_orb)
                goto alloc_fail;

        lu->logout_orb = dma_alloc_coherent(hi->host->device.parent,
                                     sizeof(struct sbp2_logout_orb),
                                     &lu->logout_orb_dma, GFP_KERNEL);
        if (!lu->logout_orb)
                goto alloc_fail;

        lu->login_orb = dma_alloc_coherent(hi->host->device.parent,
                                     sizeof(struct sbp2_login_orb),
                                     &lu->login_orb_dma, GFP_KERNEL);
        if (!lu->login_orb)
                goto alloc_fail;

        if (sbp2util_create_command_orb_pool(lu))
                goto alloc_fail;

        /* Wait a second before trying to log in. Previously logged in
         * initiators need a chance to reconnect. */
        if (msleep_interruptible(1000)) {
                sbp2_remove_device(lu);
                return -EINTR;
        }

        if (sbp2_login_device(lu)) {
                sbp2_remove_device(lu);
                return -EBUSY;
        }

        sbp2_set_busy_timeout(lu);
        sbp2_agent_reset(lu, 1);
        sbp2_max_speed_and_size(lu);

        if (lu->workarounds & SBP2_WORKAROUND_DELAY_INQUIRY)
                ssleep(SBP2_INQUIRY_DELAY);

        error = scsi_add_device(lu->shost, 0, lu->ud->id, 0);
        if (error) {
                SBP2_ERR("scsi_add_device failed");
                sbp2_logout_device(lu);
                sbp2_remove_device(lu);
                return error;
        }

        return 0;

alloc_fail:
        SBP2_ERR("Could not allocate memory for lu");
        sbp2_remove_device(lu);
        return -ENOMEM;
}

static void sbp2_remove_device(struct sbp2_lu *lu)
{
        struct sbp2_fwhost_info *hi;
        unsigned long flags;

        if (!lu)
                return;
        hi = lu->hi;
        if (!hi)
                goto no_hi;

        if (lu->shost) {
                scsi_remove_host(lu->shost);
                scsi_host_put(lu->shost);
        }
        flush_scheduled_work();
        sbp2util_remove_command_orb_pool(lu, hi->host);

        write_lock_irqsave(&sbp2_hi_logical_units_lock, flags);
        list_del(&lu->lu_list);
        write_unlock_irqrestore(&sbp2_hi_logical_units_lock, flags);

        if (lu->login_response)
                dma_free_coherent(hi->host->device.parent,
                                    sizeof(struct sbp2_login_response),
                                    lu->login_response,
                                    lu->login_response_dma);
        if (lu->login_orb)
                dma_free_coherent(hi->host->device.parent,
                                    sizeof(struct sbp2_login_orb),
                                    lu->login_orb,
                                    lu->login_orb_dma);
        if (lu->reconnect_orb)
                dma_free_coherent(hi->host->device.parent,
                                    sizeof(struct sbp2_reconnect_orb),
                                    lu->reconnect_orb,
                                    lu->reconnect_orb_dma);
        if (lu->logout_orb)
                dma_free_coherent(hi->host->device.parent,
                                    sizeof(struct sbp2_logout_orb),
                                    lu->logout_orb,
                                    lu->logout_orb_dma);
        if (lu->query_logins_orb)
                dma_free_coherent(hi->host->device.parent,
                                    sizeof(struct sbp2_query_logins_orb),
                                    lu->query_logins_orb,
                                    lu->query_logins_orb_dma);
        if (lu->query_logins_response)
                dma_free_coherent(hi->host->device.parent,
                                    sizeof(struct sbp2_query_logins_response),
                                    lu->query_logins_response,
                                    lu->query_logins_response_dma);

        if (lu->status_fifo_addr != CSR1212_INVALID_ADDR_SPACE)
                hpsb_unregister_addrspace(&sbp2_highlevel, hi->host,
                                          lu->status_fifo_addr);

        lu->ud->device.driver_data = NULL;

        module_put(hi->host->driver->owner);
no_hi:
        kfree(lu);
}

#ifdef CONFIG_IEEE1394_SBP2_PHYS_DMA
/*
 * Deal with write requests on adapters which do not support physical DMA or
 * have it switched off.
 */
static int sbp2_handle_physdma_write(struct hpsb_host *host, int nodeid,
                                     int destid, quadlet_t *data, u64 addr,
                                     size_t length, u16 flags)
{
        memcpy(bus_to_virt((u32) addr), data, length);
        return RCODE_COMPLETE;
}

/*
 * Deal with read requests on adapters which do not support physical DMA or
 * have it switched off.
 */
static int sbp2_handle_physdma_read(struct hpsb_host *host, int nodeid,
                                    quadlet_t *data, u64 addr, size_t length,
                                    u16 flags)
{
        memcpy(data, bus_to_virt((u32) addr), length);
        return RCODE_COMPLETE;
}
#endif

/**************************************
 * SBP-2 protocol related section
 **************************************/

static int sbp2_query_logins(struct sbp2_lu *lu)
{
        struct sbp2_fwhost_info *hi = lu->hi;
        quadlet_t data[2];
        int max_logins;
        int active_logins;

        lu->query_logins_orb->reserved1 = 0x0;
        lu->query_logins_orb->reserved2 = 0x0;

        lu->query_logins_orb->query_response_lo = lu->query_logins_response_dma;
        lu->query_logins_orb->query_response_hi =
                        ORB_SET_NODE_ID(hi->host->node_id);
        lu->query_logins_orb->lun_misc =
                        ORB_SET_FUNCTION(SBP2_QUERY_LOGINS_REQUEST);
        lu->query_logins_orb->lun_misc |= ORB_SET_NOTIFY(1);
        lu->query_logins_orb->lun_misc |= ORB_SET_LUN(lu->lun);

        lu->query_logins_orb->reserved_resp_length =
                ORB_SET_QUERY_LOGINS_RESP_LENGTH(
                        sizeof(struct sbp2_query_logins_response));

        lu->query_logins_orb->status_fifo_hi =
                ORB_SET_STATUS_FIFO_HI(lu->status_fifo_addr, hi->host->node_id);
        lu->query_logins_orb->status_fifo_lo =
                ORB_SET_STATUS_FIFO_LO(lu->status_fifo_addr);

        sbp2util_cpu_to_be32_buffer(lu->query_logins_orb,
                                    sizeof(struct sbp2_query_logins_orb));

        memset(lu->query_logins_response, 0,
               sizeof(struct sbp2_query_logins_response));

        data[0] = ORB_SET_NODE_ID(hi->host->node_id);
        data[1] = lu->query_logins_orb_dma;
        sbp2util_cpu_to_be32_buffer(data, 8);

        hpsb_node_write(lu->ne, lu->management_agent_addr, data, 8);

        if (sbp2util_access_timeout(lu, 2*HZ)) {
                SBP2_INFO("Error querying logins to SBP-2 device - timed out");
                return -EIO;
        }

        if (lu->status_block.ORB_offset_lo != lu->query_logins_orb_dma) {
                SBP2_INFO("Error querying logins to SBP-2 device - timed out");
                return -EIO;
        }

        if (STATUS_TEST_RDS(lu->status_block.ORB_offset_hi_misc)) {
                SBP2_INFO("Error querying logins to SBP-2 device - failed");
                return -EIO;
        }

        sbp2util_cpu_to_be32_buffer(lu->query_logins_response,
                                    sizeof(struct sbp2_query_logins_response));

        max_logins = RESPONSE_GET_MAX_LOGINS(
                        lu->query_logins_response->length_max_logins);
        SBP2_INFO("Maximum concurrent logins supported: %d", max_logins);

        active_logins = RESPONSE_GET_ACTIVE_LOGINS(
                        lu->query_logins_response->length_max_logins);
        SBP2_INFO("Number of active logins: %d", active_logins);

        if (active_logins >= max_logins) {
                return -EIO;
        }

        return 0;
}

static int sbp2_login_device(struct sbp2_lu *lu)
{
        struct sbp2_fwhost_info *hi = lu->hi;
        quadlet_t data[2];

        if (!lu->login_orb)
                return -EIO;

        if (!sbp2_exclusive_login && sbp2_query_logins(lu)) {
                SBP2_INFO("Device does not support any more concurrent logins");
                return -EIO;
        }

        /* assume no password */
        lu->login_orb->password_hi = 0;
        lu->login_orb->password_lo = 0;

        lu->login_orb->login_response_lo = lu->login_response_dma;
        lu->login_orb->login_response_hi = ORB_SET_NODE_ID(hi->host->node_id);
        lu->login_orb->lun_misc = ORB_SET_FUNCTION(SBP2_LOGIN_REQUEST);

        /* one second reconnect time */
        lu->login_orb->lun_misc |= ORB_SET_RECONNECT(0);
        lu->login_orb->lun_misc |= ORB_SET_EXCLUSIVE(sbp2_exclusive_login);
        lu->login_orb->lun_misc |= ORB_SET_NOTIFY(1);
        lu->login_orb->lun_misc |= ORB_SET_LUN(lu->lun);

        lu->login_orb->passwd_resp_lengths =
                ORB_SET_LOGIN_RESP_LENGTH(sizeof(struct sbp2_login_response));

        lu->login_orb->status_fifo_hi =
                ORB_SET_STATUS_FIFO_HI(lu->status_fifo_addr, hi->host->node_id);
        lu->login_orb->status_fifo_lo =
                ORB_SET_STATUS_FIFO_LO(lu->status_fifo_addr);

        sbp2util_cpu_to_be32_buffer(lu->login_orb,
                                    sizeof(struct sbp2_login_orb));

        memset(lu->login_response, 0, sizeof(struct sbp2_login_response));

        data[0] = ORB_SET_NODE_ID(hi->host->node_id);
        data[1] = lu->login_orb_dma;
        sbp2util_cpu_to_be32_buffer(data, 8);

        hpsb_node_write(lu->ne, lu->management_agent_addr, data, 8);

        /* wait up to 20 seconds for login status */
        if (sbp2util_access_timeout(lu, 20*HZ)) {
                SBP2_ERR("Error logging into SBP-2 device - timed out");
                return -EIO;
        }

        /* make sure that the returned status matches the login ORB */
        if (lu->status_block.ORB_offset_lo != lu->login_orb_dma) {
                SBP2_ERR("Error logging into SBP-2 device - timed out");
                return -EIO;
        }

        if (STATUS_TEST_RDS(lu->status_block.ORB_offset_hi_misc)) {
                SBP2_ERR("Error logging into SBP-2 device - failed");
                return -EIO;
        }

        sbp2util_cpu_to_be32_buffer(lu->login_response,
                                    sizeof(struct sbp2_login_response));
        lu->command_block_agent_addr =
                        ((u64)lu->login_response->command_block_agent_hi) << 32;
        lu->command_block_agent_addr |=
                        ((u64)lu->login_response->command_block_agent_lo);
        lu->command_block_agent_addr &= 0x0000ffffffffffffULL;

        SBP2_INFO("Logged into SBP-2 device");
        return 0;
}

static int sbp2_logout_device(struct sbp2_lu *lu)
{
        struct sbp2_fwhost_info *hi = lu->hi;
        quadlet_t data[2];
        int error;

        lu->logout_orb->reserved1 = 0x0;
        lu->logout_orb->reserved2 = 0x0;
        lu->logout_orb->reserved3 = 0x0;
        lu->logout_orb->reserved4 = 0x0;

        lu->logout_orb->login_ID_misc = ORB_SET_FUNCTION(SBP2_LOGOUT_REQUEST);
        lu->logout_orb->login_ID_misc |=
                        ORB_SET_LOGIN_ID(lu->login_response->length_login_ID);
        lu->logout_orb->login_ID_misc |= ORB_SET_NOTIFY(1);

        lu->logout_orb->reserved5 = 0x0;
        lu->logout_orb->status_fifo_hi =
                ORB_SET_STATUS_FIFO_HI(lu->status_fifo_addr, hi->host->node_id);
        lu->logout_orb->status_fifo_lo =
                ORB_SET_STATUS_FIFO_LO(lu->status_fifo_addr);

        sbp2util_cpu_to_be32_buffer(lu->logout_orb,
                                    sizeof(struct sbp2_logout_orb));

        data[0] = ORB_SET_NODE_ID(hi->host->node_id);
        data[1] = lu->logout_orb_dma;
        sbp2util_cpu_to_be32_buffer(data, 8);

        error = hpsb_node_write(lu->ne, lu->management_agent_addr, data, 8);
        if (error)
                return error;

        /* wait up to 1 second for the device to complete logout */
        if (sbp2util_access_timeout(lu, HZ))
                return -EIO;

        SBP2_INFO("Logged out of SBP-2 device");
        return 0;
}

static int sbp2_reconnect_device(struct sbp2_lu *lu)
{
        struct sbp2_fwhost_info *hi = lu->hi;
        quadlet_t data[2];
        int error;

        lu->reconnect_orb->reserved1 = 0x0;
        lu->reconnect_orb->reserved2 = 0x0;
        lu->reconnect_orb->reserved3 = 0x0;
        lu->reconnect_orb->reserved4 = 0x0;

        lu->reconnect_orb->login_ID_misc =
                        ORB_SET_FUNCTION(SBP2_RECONNECT_REQUEST);
        lu->reconnect_orb->login_ID_misc |=
                        ORB_SET_LOGIN_ID(lu->login_response->length_login_ID);
        lu->reconnect_orb->login_ID_misc |= ORB_SET_NOTIFY(1);

        lu->reconnect_orb->reserved5 = 0x0;
        lu->reconnect_orb->status_fifo_hi =
                ORB_SET_STATUS_FIFO_HI(lu->status_fifo_addr, hi->host->node_id);
        lu->reconnect_orb->status_fifo_lo =
                ORB_SET_STATUS_FIFO_LO(lu->status_fifo_addr);

        sbp2util_cpu_to_be32_buffer(lu->reconnect_orb,
                                    sizeof(struct sbp2_reconnect_orb));

        data[0] = ORB_SET_NODE_ID(hi->host->node_id);
        data[1] = lu->reconnect_orb_dma;
        sbp2util_cpu_to_be32_buffer(data, 8);

        error = hpsb_node_write(lu->ne, lu->management_agent_addr, data, 8);
        if (error)
                return error;

        /* wait up to 1 second for reconnect status */
        if (sbp2util_access_timeout(lu, HZ)) {
                SBP2_ERR("Error reconnecting to SBP-2 device - timed out");
                return -EIO;
        }

        /* make sure that the returned status matches the reconnect ORB */
        if (lu->status_block.ORB_offset_lo != lu->reconnect_orb_dma) {
                SBP2_ERR("Error reconnecting to SBP-2 device - timed out");
                return -EIO;
        }

        if (STATUS_TEST_RDS(lu->status_block.ORB_offset_hi_misc)) {
                SBP2_ERR("Error reconnecting to SBP-2 device - failed");
                return -EIO;
        }

        SBP2_INFO("Reconnected to SBP-2 device");
        return 0;
}

/*
 * Set the target node's Single Phase Retry limit. Affects the target's retry
 * behaviour if our node is too busy to accept requests.
 */
static int sbp2_set_busy_timeout(struct sbp2_lu *lu)
{
        quadlet_t data;

        data = cpu_to_be32(SBP2_BUSY_TIMEOUT_VALUE);
        if (hpsb_node_write(lu->ne, SBP2_BUSY_TIMEOUT_ADDRESS, &data, 4))
                SBP2_ERR("%s error", __func__);
        return 0;
}

static void sbp2_parse_unit_directory(struct sbp2_lu *lu,
                                      struct unit_directory *ud)
{
        struct csr1212_keyval *kv;
        struct csr1212_dentry *dentry;
        u64 management_agent_addr;
        u32 unit_characteristics, firmware_revision;
        unsigned workarounds;
        int i;

        management_agent_addr = 0;
        unit_characteristics = 0;
        firmware_revision = 0;

        csr1212_for_each_dir_entry(ud->ne->csr, kv, ud->ud_kv, dentry) {
                switch (kv->key.id) {
                case CSR1212_KV_ID_DEPENDENT_INFO:
                        if (kv->key.type == CSR1212_KV_TYPE_CSR_OFFSET)
                                management_agent_addr =
                                    CSR1212_REGISTER_SPACE_BASE +
                                    (kv->value.csr_offset << 2);

                        else if (kv->key.type == CSR1212_KV_TYPE_IMMEDIATE)
                                lu->lun = ORB_SET_LUN(kv->value.immediate);
                        break;

                case SBP2_UNIT_CHARACTERISTICS_KEY:
                        /* FIXME: This is ignored so far.
                         * See SBP-2 clause 7.4.8. */
                        unit_characteristics = kv->value.immediate;
                        break;

                case SBP2_FIRMWARE_REVISION_KEY:
                        firmware_revision = kv->value.immediate;
                        break;

                default:
                        /* FIXME: Check for SBP2_DEVICE_TYPE_AND_LUN_KEY.
                         * Its "ordered" bit has consequences for command ORB
                         * list handling. See SBP-2 clauses 4.6, 7.4.11, 10.2 */
                        break;
                }
        }

        workarounds = sbp2_default_workarounds;

        if (!(workarounds & SBP2_WORKAROUND_OVERRIDE))
                for (i = 0; i < ARRAY_SIZE(sbp2_workarounds_table); i++) {
                        if (sbp2_workarounds_table[i].firmware_revision !=
                            SBP2_ROM_VALUE_WILDCARD &&
                            sbp2_workarounds_table[i].firmware_revision !=
                            (firmware_revision & 0xffff00))
                                continue;
                        if (sbp2_workarounds_table[i].model_id !=
                            SBP2_ROM_VALUE_WILDCARD &&
                            sbp2_workarounds_table[i].model_id != ud->model_id)
                                continue;
                        workarounds |= sbp2_workarounds_table[i].workarounds;
                        break;
                }

        if (workarounds)
                SBP2_INFO("Workarounds for node " NODE_BUS_FMT ": 0x%x "
                          "(firmware_revision 0x%06x, vendor_id 0x%06x,"
                          " model_id 0x%06x)",
                          NODE_BUS_ARGS(ud->ne->host, ud->ne->nodeid),
                          workarounds, firmware_revision,
                          ud->vendor_id ? ud->vendor_id : ud->ne->vendor_id,
                          ud->model_id);

        /* We would need one SCSI host template for each target to adjust
         * max_sectors on the fly, therefore warn only. */
        if (workarounds & SBP2_WORKAROUND_128K_MAX_TRANS &&
            (sbp2_max_sectors * 512) > (128 * 1024))
                SBP2_INFO("Node " NODE_BUS_FMT ": Bridge only supports 128KB "
                          "max transfer size. WARNING: Current max_sectors "
                          "setting is larger than 128KB (%d sectors)",
                          NODE_BUS_ARGS(ud->ne->host, ud->ne->nodeid),
                          sbp2_max_sectors);

        /* If this is a logical unit directory entry, process the parent
         * to get the values. */
        if (ud->flags & UNIT_DIRECTORY_LUN_DIRECTORY) {
                struct unit_directory *parent_ud = container_of(
                        ud->device.parent, struct unit_directory, device);
                sbp2_parse_unit_directory(lu, parent_ud);
        } else {
                lu->management_agent_addr = management_agent_addr;
                lu->workarounds = workarounds;
                if (ud->flags & UNIT_DIRECTORY_HAS_LUN)
                        lu->lun = ORB_SET_LUN(ud->lun);
        }
}

#define SBP2_PAYLOAD_TO_BYTES(p) (1 << ((p) + 2))

/*
 * This function is called in order to determine the max speed and packet
 * size we can use in our ORBs. Note, that we (the driver and host) only
 * initiate the transaction. The SBP-2 device actually transfers the data
 * (by reading from the DMA area we tell it). This means that the SBP-2
 * device decides the actual maximum data it can transfer. We just tell it
 * the speed that it needs to use, and the max_rec the host supports, and
 * it takes care of the rest.
 */
static int sbp2_max_speed_and_size(struct sbp2_lu *lu)
{
        struct sbp2_fwhost_info *hi = lu->hi;
        u8 payload;

        lu->speed_code = hi->host->speed[NODEID_TO_NODE(lu->ne->nodeid)];

        if (lu->speed_code > sbp2_max_speed) {
                lu->speed_code = sbp2_max_speed;
                SBP2_INFO("Reducing speed to %s",
                          hpsb_speedto_str[sbp2_max_speed]);
        }

        /* Payload size is the lesser of what our speed supports and what
         * our host supports.  */
        payload = min(sbp2_speedto_max_payload[lu->speed_code],
                      (u8) (hi->host->csr.max_rec - 1));

        /* If physical DMA is off, work around limitation in ohci1394:
         * packet size must not exceed PAGE_SIZE */
        if (lu->ne->host->low_addr_space < (1ULL << 32))
                while (SBP2_PAYLOAD_TO_BYTES(payload) + 24 > PAGE_SIZE &&
                       payload)
                        payload--;

        SBP2_INFO("Node " NODE_BUS_FMT ": Max speed [%s] - Max payload [%u]",
                  NODE_BUS_ARGS(hi->host, lu->ne->nodeid),
                  hpsb_speedto_str[lu->speed_code],
                  SBP2_PAYLOAD_TO_BYTES(payload));

        lu->max_payload_size = payload;
        return 0;
}

static int sbp2_agent_reset(struct sbp2_lu *lu, int wait)
{
        quadlet_t data;
        u64 addr;
        int retval;
        unsigned long flags;

        /* flush lu->protocol_work */
        if (wait)
                flush_scheduled_work();

        data = ntohl(SBP2_AGENT_RESET_DATA);
        addr = lu->command_block_agent_addr + SBP2_AGENT_RESET_OFFSET;

        if (wait)
                retval = hpsb_node_write(lu->ne, addr, &data, 4);
        else
                retval = sbp2util_node_write_no_wait(lu->ne, addr, &data, 4);

        if (retval < 0) {
                SBP2_ERR("hpsb_node_write failed.\n");
                return -EIO;
        }

        /* make sure that the ORB_POINTER is written on next command */
        spin_lock_irqsave(&lu->cmd_orb_lock, flags);
        lu->last_orb = NULL;
        spin_unlock_irqrestore(&lu->cmd_orb_lock, flags);

        return 0;
}

static void sbp2_prep_command_orb_sg(struct sbp2_command_orb *orb,
                                     struct sbp2_fwhost_info *hi,
                                     struct sbp2_command_info *cmd,
                                     unsigned int scsi_use_sg,
                                     struct scatterlist *sg,
                                     u32 orb_direction,
                                     enum dma_data_direction dma_dir)
{
        cmd->dma_dir = dma_dir;
        orb->data_descriptor_hi = ORB_SET_NODE_ID(hi->host->node_id);
        orb->misc |= ORB_SET_DIRECTION(orb_direction);

        /* special case if only one element (and less than 64KB in size) */
        if (scsi_use_sg == 1 && sg->length <= SBP2_MAX_SG_ELEMENT_LENGTH) {

                cmd->dma_size = sg->length;
                cmd->dma_type = CMD_DMA_PAGE;
                cmd->cmd_dma = dma_map_page(hi->host->device.parent,
                                            sg_page(sg), sg->offset,
                                            cmd->dma_size, cmd->dma_dir);

                orb->data_descriptor_lo = cmd->cmd_dma;
                orb->misc |= ORB_SET_DATA_SIZE(cmd->dma_size);

        } else {
                struct sbp2_unrestricted_page_table *sg_element =
                                                &cmd->scatter_gather_element[0];
                u32 sg_count, sg_len;
                dma_addr_t sg_addr;
                int i, count = dma_map_sg(hi->host->device.parent, sg,
                                          scsi_use_sg, dma_dir);

                cmd->dma_size = scsi_use_sg;
                cmd->sge_buffer = sg;

                /* use page tables (s/g) */
                orb->misc |= ORB_SET_PAGE_TABLE_PRESENT(0x1);
                orb->data_descriptor_lo = cmd->sge_dma;

                /* loop through and fill out our SBP-2 page tables
                 * (and split up anything too large) */
                for (i = 0, sg_count = 0; i < count; i++, sg = sg_next(sg)) {
                        sg_len = sg_dma_len(sg);
                        sg_addr = sg_dma_address(sg);
                        while (sg_len) {
                                sg_element[sg_count].segment_base_lo = sg_addr;
                                if (sg_len > SBP2_MAX_SG_ELEMENT_LENGTH) {
                                        sg_element[sg_count].length_segment_base_hi =
                                                PAGE_TABLE_SET_SEGMENT_LENGTH(SBP2_MAX_SG_ELEMENT_LENGTH);
                                        sg_addr += SBP2_MAX_SG_ELEMENT_LENGTH;
                                        sg_len -= SBP2_MAX_SG_ELEMENT_LENGTH;
                                } else {
                                        sg_element[sg_count].length_segment_base_hi =
                                                PAGE_TABLE_SET_SEGMENT_LENGTH(sg_len);
                                        sg_len = 0;
                                }
                                sg_count++;
                        }
                }

                orb->misc |= ORB_SET_DATA_SIZE(sg_count);

                sbp2util_cpu_to_be32_buffer(sg_element,
                                (sizeof(struct sbp2_unrestricted_page_table)) *
                                sg_count);
        }
}

static void sbp2_create_command_orb(struct sbp2_lu *lu,
                                    struct sbp2_command_info *cmd,
                                    struct scsi_cmnd *SCpnt)
{
        struct sbp2_fwhost_info *hi = lu->hi;
        struct sbp2_command_orb *orb = &cmd->command_orb;
        u32 orb_direction;
        unsigned int scsi_request_bufflen = scsi_bufflen(SCpnt);
        enum dma_data_direction dma_dir = SCpnt->sc_data_direction;

        /*
         * Set-up our command ORB.
         *
         * NOTE: We're doing unrestricted page tables (s/g), as this is
         * best performance (at least with the devices I have). This means
         * that data_size becomes the number of s/g elements, and
         * page_size should be zero (for unrestricted).
         */
        orb->next_ORB_hi = ORB_SET_NULL_PTR(1);
        orb->next_ORB_lo = 0x0;
        orb->misc = ORB_SET_MAX_PAYLOAD(lu->max_payload_size);
        orb->misc |= ORB_SET_SPEED(lu->speed_code);
        orb->misc |= ORB_SET_NOTIFY(1);

        if (dma_dir == DMA_NONE)
                orb_direction = ORB_DIRECTION_NO_DATA_TRANSFER;
        else if (dma_dir == DMA_TO_DEVICE && scsi_request_bufflen)
                orb_direction = ORB_DIRECTION_WRITE_TO_MEDIA;
        else if (dma_dir == DMA_FROM_DEVICE && scsi_request_bufflen)
                orb_direction = ORB_DIRECTION_READ_FROM_MEDIA;
        else {
                SBP2_INFO("Falling back to DMA_NONE");
                orb_direction = ORB_DIRECTION_NO_DATA_TRANSFER;
        }

        /* set up our page table stuff */
        if (orb_direction == ORB_DIRECTION_NO_DATA_TRANSFER) {
                orb->data_descriptor_hi = 0x0;
                orb->data_descriptor_lo = 0x0;
                orb->misc |= ORB_SET_DIRECTION(1);
        } else
                sbp2_prep_command_orb_sg(orb, hi, cmd, scsi_sg_count(SCpnt),
                                         scsi_sglist(SCpnt),
                                         orb_direction, dma_dir);

        sbp2util_cpu_to_be32_buffer(orb, sizeof(*orb));

        memset(orb->cdb, 0, sizeof(orb->cdb));
        memcpy(orb->cdb, SCpnt->cmnd, SCpnt->cmd_len);
}

static void sbp2_link_orb_command(struct sbp2_lu *lu,
                                  struct sbp2_command_info *cmd)
{
        struct sbp2_fwhost_info *hi = lu->hi;
        struct sbp2_command_orb *last_orb;
        dma_addr_t last_orb_dma;
        u64 addr = lu->command_block_agent_addr;
        quadlet_t data[2];
        size_t length;
        unsigned long flags;

        dma_sync_single_for_device(hi->host->device.parent,
                                   cmd->command_orb_dma,
                                   sizeof(struct sbp2_command_orb),
                                   DMA_TO_DEVICE);
        dma_sync_single_for_device(hi->host->device.parent, cmd->sge_dma,
                                   sizeof(cmd->scatter_gather_element),
                                   DMA_TO_DEVICE);

        /* check to see if there are any previous orbs to use */
        spin_lock_irqsave(&lu->cmd_orb_lock, flags);
        last_orb = lu->last_orb;
        last_orb_dma = lu->last_orb_dma;
        if (!last_orb) {
                /*
                 * last_orb == NULL means: We know that the target's fetch agent
                 * is not active right now.
                 */
                addr += SBP2_ORB_POINTER_OFFSET;
                data[0] = ORB_SET_NODE_ID(hi->host->node_id);
                data[1] = cmd->command_orb_dma;
                sbp2util_cpu_to_be32_buffer(data, 8);
                length = 8;
        } else {
                /*
                 * last_orb != NULL means: We know that the target's fetch agent
                 * is (very probably) not dead or in reset state right now.
                 * We have an ORB already sent that we can append a new one to.
                 * The target's fetch agent may or may not have read this
                 * previous ORB yet.
                 */
                dma_sync_single_for_cpu(hi->host->device.parent, last_orb_dma,
                                        sizeof(struct sbp2_command_orb),
                                        DMA_TO_DEVICE);
                last_orb->next_ORB_lo = cpu_to_be32(cmd->command_orb_dma);
                wmb();
                /* Tells hardware that this pointer is valid */
                last_orb->next_ORB_hi = 0;
                dma_sync_single_for_device(hi->host->device.parent,
                                           last_orb_dma,
                                           sizeof(struct sbp2_command_orb),
                                           DMA_TO_DEVICE);
                addr += SBP2_DOORBELL_OFFSET;
                data[0] = 0;
                length = 4;
        }
        lu->last_orb = &cmd->command_orb;
        lu->last_orb_dma = cmd->command_orb_dma;
        spin_unlock_irqrestore(&lu->cmd_orb_lock, flags);

        if (sbp2util_node_write_no_wait(lu->ne, addr, data, length)) {
                /*
                 * sbp2util_node_write_no_wait failed. We certainly ran out
                 * of transaction labels, perhaps just because there were no
                 * context switches which gave khpsbpkt a chance to collect
                 * free tlabels. Try again in non-atomic context. If necessary,
                 * the workqueue job will sleep to guaranteedly get a tlabel.
                 * We do not accept new commands until the job is over.
                 */
                scsi_block_requests(lu->shost);
                PREPARE_WORK(&lu->protocol_work,
                             last_orb ? sbp2util_write_doorbell:
                                        sbp2util_write_orb_pointer);
                schedule_work(&lu->protocol_work);
        }
}

static int sbp2_send_command(struct sbp2_lu *lu, struct scsi_cmnd *SCpnt,
                             void (*done)(struct scsi_cmnd *))
{
        struct sbp2_command_info *cmd;

        cmd = sbp2util_allocate_command_orb(lu, SCpnt, done);
        if (!cmd)
                return -EIO;

        sbp2_create_command_orb(lu, cmd, SCpnt);
        sbp2_link_orb_command(lu, cmd);

        return 0;
}

/*
 * Translates SBP-2 status into SCSI sense data for check conditions
 */
static unsigned int sbp2_status_to_sense_data(unchar *sbp2_status,
                                              unchar *sense_data)
{
        /* OK, it's pretty ugly... ;-) */
        sense_data[0] = 0x70;
        sense_data[1] = 0x0;
        sense_data[2] = sbp2_status[9];
        sense_data[3] = sbp2_status[12];
        sense_data[4] = sbp2_status[13];
        sense_data[5] = sbp2_status[14];
        sense_data[6] = sbp2_status[15];
        sense_data[7] = 10;
        sense_data[8] = sbp2_status[16];
        sense_data[9] = sbp2_status[17];
        sense_data[10] = sbp2_status[18];
        sense_data[11] = sbp2_status[19];
        sense_data[12] = sbp2_status[10];
        sense_data[13] = sbp2_status[11];
        sense_data[14] = sbp2_status[20];
        sense_data[15] = sbp2_status[21];

        return sbp2_status[8] & 0x3f;
}

static int sbp2_handle_status_write(struct hpsb_host *host, int nodeid,
                                    int destid, quadlet_t *data, u64 addr,
                                    size_t length, u16 fl)
{
        struct sbp2_fwhost_info *hi;
        struct sbp2_lu *lu = NULL, *lu_tmp;
        struct scsi_cmnd *SCpnt = NULL;
        struct sbp2_status_block *sb;
        u32 scsi_status = SBP2_SCSI_STATUS_GOOD;
        struct sbp2_command_info *cmd;
        unsigned long flags;

        if (unlikely(length < 8 || length > sizeof(struct sbp2_status_block))) {
                SBP2_ERR("Wrong size of status block");
                return RCODE_ADDRESS_ERROR;
        }
        if (unlikely(!host)) {
                SBP2_ERR("host is NULL - this is bad!");
                return RCODE_ADDRESS_ERROR;
        }
        hi = hpsb_get_hostinfo(&sbp2_highlevel, host);
        if (unlikely(!hi)) {
                SBP2_ERR("host info is NULL - this is bad!");
                return RCODE_ADDRESS_ERROR;
        }

        /* Find the unit which wrote the status. */
        read_lock_irqsave(&sbp2_hi_logical_units_lock, flags);
        list_for_each_entry(lu_tmp, &hi->logical_units, lu_list) {
                if (lu_tmp->ne->nodeid == nodeid &&
                    lu_tmp->status_fifo_addr == addr) {
                        lu = lu_tmp;
                        break;
                }
        }
        read_unlock_irqrestore(&sbp2_hi_logical_units_lock, flags);

        if (unlikely(!lu)) {
                SBP2_ERR("lu is NULL - device is gone?");
                return RCODE_ADDRESS_ERROR;
        }

        /* Put response into lu status fifo buffer. The first two bytes
         * come in big endian bit order. Often the target writes only a
         * truncated status block, minimally the first two quadlets. The rest
         * is implied to be zeros. */
        sb = &lu->status_block;
        memset(sb->command_set_dependent, 0, sizeof(sb->command_set_dependent));
        memcpy(sb, data, length);
        sbp2util_be32_to_cpu_buffer(sb, 8);

        /* Ignore unsolicited status. Handle command ORB status. */
        if (unlikely(STATUS_GET_SRC(sb->ORB_offset_hi_misc) == 2))
                cmd = NULL;
        else
                cmd = sbp2util_find_command_for_orb(lu, sb->ORB_offset_lo);
        if (cmd) {
                dma_sync_single_for_cpu(hi->host->device.parent,
                                        cmd->command_orb_dma,
                                        sizeof(struct sbp2_command_orb),
                                        DMA_TO_DEVICE);
                dma_sync_single_for_cpu(hi->host->device.parent, cmd->sge_dma,
                                        sizeof(cmd->scatter_gather_element),
                                        DMA_TO_DEVICE);
                /* Grab SCSI command pointers and check status. */
                /*
                 * FIXME: If the src field in the status is 1, the ORB DMA must
                 * not be reused until status for a subsequent ORB is received.
                 */
                SCpnt = cmd->Current_SCpnt;
                spin_lock_irqsave(&lu->cmd_orb_lock, flags);
                sbp2util_mark_command_completed(lu, cmd);
                spin_unlock_irqrestore(&lu->cmd_orb_lock, flags);

                if (SCpnt) {
                        u32 h = sb->ORB_offset_hi_misc;
                        u32 r = STATUS_GET_RESP(h);

                        if (r != RESP_STATUS_REQUEST_COMPLETE) {
                                SBP2_INFO("resp 0x%x, sbp_status 0x%x",
                                          r, STATUS_GET_SBP_STATUS(h));
                                scsi_status =
                                        r == RESP_STATUS_TRANSPORT_FAILURE ?
                                        SBP2_SCSI_STATUS_BUSY :
                                        SBP2_SCSI_STATUS_COMMAND_TERMINATED;
                        }

                        if (STATUS_GET_LEN(h) > 1)
                                scsi_status = sbp2_status_to_sense_data(
                                        (unchar *)sb, SCpnt->sense_buffer);

                        if (STATUS_TEST_DEAD(h))
                                sbp2_agent_reset(lu, 0);
                }

                /* Check here to see if there are no commands in-use. If there
                 * are none, we know that the fetch agent left the active state
                 * _and_ that we did not reactivate it yet. Therefore clear
                 * last_orb so that next time we write directly to the
                 * ORB_POINTER register. That way the fetch agent does not need
                 * to refetch the next_ORB. */
                spin_lock_irqsave(&lu->cmd_orb_lock, flags);
                if (list_empty(&lu->cmd_orb_inuse))
                        lu->last_orb = NULL;
                spin_unlock_irqrestore(&lu->cmd_orb_lock, flags);

        } else {
                /* It's probably status after a management request. */
                if ((sb->ORB_offset_lo == lu->reconnect_orb_dma) ||
                    (sb->ORB_offset_lo == lu->login_orb_dma) ||
                    (sb->ORB_offset_lo == lu->query_logins_orb_dma) ||
                    (sb->ORB_offset_lo == lu->logout_orb_dma)) {
                        lu->access_complete = 1;
                        wake_up_interruptible(&sbp2_access_wq);
                }
        }

        if (SCpnt)
                sbp2scsi_complete_command(lu, scsi_status, SCpnt,
                                          cmd->Current_done);
        return RCODE_COMPLETE;
}

/**************************************
 * SCSI interface related section
 **************************************/

static int sbp2scsi_queuecommand(struct scsi_cmnd *SCpnt,
                                 void (*done)(struct scsi_cmnd *))
{
        struct sbp2_lu *lu = (struct sbp2_lu *)SCpnt->device->host->hostdata[0];
        struct sbp2_fwhost_info *hi;
        int result = DID_NO_CONNECT << 16;

        if (unlikely(!sbp2util_node_is_available(lu)))
                goto done;

        hi = lu->hi;

        if (unlikely(!hi)) {
                SBP2_ERR("sbp2_fwhost_info is NULL - this is bad!");
                goto done;
        }

        /* Multiple units are currently represented to the SCSI core as separate
         * targets, not as one target with multiple LUs. Therefore return
         * selection time-out to any IO directed at non-zero LUNs. */
        if (unlikely(SCpnt->device->lun))
                goto done;

        if (unlikely(!hpsb_node_entry_valid(lu->ne))) {
                SBP2_ERR("Bus reset in progress - rejecting command");
                result = DID_BUS_BUSY << 16;
                goto done;
        }

        /* Bidirectional commands are not yet implemented,
         * and unknown transfer direction not handled. */
        if (unlikely(SCpnt->sc_data_direction == DMA_BIDIRECTIONAL)) {
                SBP2_ERR("Cannot handle DMA_BIDIRECTIONAL - rejecting command");
                result = DID_ERROR << 16;
                goto done;
        }

        if (sbp2_send_command(lu, SCpnt, done)) {
                SBP2_ERR("Error sending SCSI command");
                sbp2scsi_complete_command(lu,
                                          SBP2_SCSI_STATUS_SELECTION_TIMEOUT,
                                          SCpnt, done);
        }
        return 0;

done:
        SCpnt->result = result;
        done(SCpnt);
        return 0;
}

static void sbp2scsi_complete_all_commands(struct sbp2_lu *lu, u32 status)
{
        struct sbp2_fwhost_info *hi = lu->hi;
        struct list_head *lh;
        struct sbp2_command_info *cmd;
        unsigned long flags;

        spin_lock_irqsave(&lu->cmd_orb_lock, flags);
        while (!list_empty(&lu->cmd_orb_inuse)) {
                lh = lu->cmd_orb_inuse.next;
                cmd = list_entry(lh, struct sbp2_command_info, list);
                dma_sync_single_for_cpu(hi->host->device.parent,
                                        cmd->command_orb_dma,
                                        sizeof(struct sbp2_command_orb),
                                        DMA_TO_DEVICE);
                dma_sync_single_for_cpu(hi->host->device.parent, cmd->sge_dma,
                                        sizeof(cmd->scatter_gather_element),
                                        DMA_TO_DEVICE);
                sbp2util_mark_command_completed(lu, cmd);
                if (cmd->Current_SCpnt) {
                        cmd->Current_SCpnt->result = status << 16;
                        cmd->Current_done(cmd->Current_SCpnt);
                }
        }
        spin_unlock_irqrestore(&lu->cmd_orb_lock, flags);

        return;
}

/*
 * Complete a regular SCSI command. Can be called in atomic context.
 */
static void sbp2scsi_complete_command(struct sbp2_lu *lu, u32 scsi_status,
                                      struct scsi_cmnd *SCpnt,
                                      void (*done)(struct scsi_cmnd *))
{
        if (!SCpnt) {
                SBP2_ERR("SCpnt is NULL");
                return;
        }

        switch (scsi_status) {
        case SBP2_SCSI_STATUS_GOOD:
                SCpnt->result = DID_OK << 16;
                break;

        case SBP2_SCSI_STATUS_BUSY:
                SBP2_ERR("SBP2_SCSI_STATUS_BUSY");
                SCpnt->result = DID_BUS_BUSY << 16;
                break;

        case SBP2_SCSI_STATUS_CHECK_CONDITION:
                SCpnt->result = CHECK_CONDITION << 1 | DID_OK << 16;
                break;

        case SBP2_SCSI_STATUS_SELECTION_TIMEOUT:
                SBP2_ERR("SBP2_SCSI_STATUS_SELECTION_TIMEOUT");
                SCpnt->result = DID_NO_CONNECT << 16;
                scsi_print_command(SCpnt);
                break;

        case SBP2_SCSI_STATUS_CONDITION_MET:
        case SBP2_SCSI_STATUS_RESERVATION_CONFLICT:
        case SBP2_SCSI_STATUS_COMMAND_TERMINATED:
                SBP2_ERR("Bad SCSI status = %x", scsi_status);
                SCpnt->result = DID_ERROR << 16;
                scsi_print_command(SCpnt);
                break;

        default:
                SBP2_ERR("Unsupported SCSI status = %x", scsi_status);
                SCpnt->result = DID_ERROR << 16;
        }

        /* If a bus reset is in progress and there was an error, complete
         * the command as busy so that it will get retried. */
        if (!hpsb_node_entry_valid(lu->ne)
            && (scsi_status != SBP2_SCSI_STATUS_GOOD)) {
                SBP2_ERR("Completing command with busy (bus reset)");
                SCpnt->result = DID_BUS_BUSY << 16;
        }

        /* Tell the SCSI stack that we're done with this command. */
        done(SCpnt);
}

static int sbp2scsi_slave_alloc(struct scsi_device *sdev)
{
        struct sbp2_lu *lu = (struct sbp2_lu *)sdev->host->hostdata[0];

        if (sdev->lun != 0 || sdev->id != lu->ud->id || sdev->channel != 0)
                return -ENODEV;

        lu->sdev = sdev;
        sdev->allow_restart = 1;

        /* SBP-2 requires quadlet alignment of the data buffers. */
        blk_queue_update_dma_alignment(sdev->request_queue, 4 - 1);

        if (lu->workarounds & SBP2_WORKAROUND_INQUIRY_36)
                sdev->inquiry_len = 36;
        return 0;
}

static int sbp2scsi_slave_configure(struct scsi_device *sdev)
{
        struct sbp2_lu *lu = (struct sbp2_lu *)sdev->host->hostdata[0];

        sdev->use_10_for_rw = 1;

        if (sbp2_exclusive_login)
                sdev->manage_start_stop = 1;
        if (sdev->type == TYPE_ROM)
                sdev->use_10_for_ms = 1;
        if (sdev->type == TYPE_DISK &&
            lu->workarounds & SBP2_WORKAROUND_MODE_SENSE_8)
                sdev->skip_ms_page_8 = 1;
        if (lu->workarounds & SBP2_WORKAROUND_FIX_CAPACITY)
                sdev->fix_capacity = 1;
        if (lu->workarounds & SBP2_WORKAROUND_POWER_CONDITION)
                sdev->start_stop_pwr_cond = 1;
        if (lu->workarounds & SBP2_WORKAROUND_128K_MAX_TRANS)
                blk_queue_max_sectors(sdev->request_queue, 128 * 1024 / 512);
        return 0;
}

static void sbp2scsi_slave_destroy(struct scsi_device *sdev)
{
        ((struct sbp2_lu *)sdev->host->hostdata[0])->sdev = NULL;
        return;
}

/*
 * Called by scsi stack when something has really gone wrong.
 * Usually called when a command has timed-out for some reason.
 */
static int sbp2scsi_abort(struct scsi_cmnd *SCpnt)
{
        struct sbp2_lu *lu = (struct sbp2_lu *)SCpnt->device->host->hostdata[0];
        struct sbp2_fwhost_info *hi = lu->hi;
        struct sbp2_command_info *cmd;
        unsigned long flags;

        SBP2_INFO("aborting sbp2 command");
        scsi_print_command(SCpnt);

        if (sbp2util_node_is_available(lu)) {
                sbp2_agent_reset(lu, 1);

                /* Return a matching command structure to the free pool. */
                spin_lock_irqsave(&lu->cmd_orb_lock, flags);
                cmd = sbp2util_find_command_for_SCpnt(lu, SCpnt);
                if (cmd) {
                        dma_sync_single_for_cpu(hi->host->device.parent,
                                        cmd->command_orb_dma,
                                        sizeof(struct sbp2_command_orb),
                                        DMA_TO_DEVICE);
                        dma_sync_single_for_cpu(hi->host->device.parent,
                                        cmd->sge_dma,
                                        sizeof(cmd->scatter_gather_element),
                                        DMA_TO_DEVICE);
                        sbp2util_mark_command_completed(lu, cmd);
                        if (cmd->Current_SCpnt) {
                                cmd->Current_SCpnt->result = DID_ABORT << 16;
                                cmd->Current_done(cmd->Current_SCpnt);
                        }
                }
                spin_unlock_irqrestore(&lu->cmd_orb_lock, flags);

                sbp2scsi_complete_all_commands(lu, DID_BUS_BUSY);
        }

        return SUCCESS;
}

/*
 * Called by scsi stack when something has really gone wrong.
 */
static int sbp2scsi_reset(struct scsi_cmnd *SCpnt)
{
        struct sbp2_lu *lu = (struct sbp2_lu *)SCpnt->device->host->hostdata[0];

        SBP2_INFO("reset requested");

        if (sbp2util_node_is_available(lu)) {
                SBP2_INFO("generating sbp2 fetch agent reset");
                sbp2_agent_reset(lu, 1);
        }

        return SUCCESS;
}

static ssize_t sbp2_sysfs_ieee1394_id_show(struct device *dev,
                                           struct device_attribute *attr,
                                           char *buf)
{
        struct scsi_device *sdev;
        struct sbp2_lu *lu;

        if (!(sdev = to_scsi_device(dev)))
                return 0;

        if (!(lu = (struct sbp2_lu *)sdev->host->hostdata[0]))
                return 0;

        if (sbp2_long_sysfs_ieee1394_id)
                return sprintf(buf, "%016Lx:%06x:%04x\n",
                                (unsigned long long)lu->ne->guid,
                                lu->ud->directory_id, ORB_SET_LUN(lu->lun));
        else
                return sprintf(buf, "%016Lx:%d:%d\n",
                                (unsigned long long)lu->ne->guid,
                                lu->ud->id, ORB_SET_LUN(lu->lun));
}

MODULE_AUTHOR("Ben Collins <bcollins@debian.org>");
MODULE_DESCRIPTION("IEEE-1394 SBP-2 protocol driver");
MODULE_SUPPORTED_DEVICE(SBP2_DEVICE_NAME);
MODULE_LICENSE("GPL");

static int sbp2_module_init(void)
{
        int ret;

        if (sbp2_serialize_io) {
                sbp2_shost_template.can_queue = 1;
                sbp2_shost_template.cmd_per_lun = 1;
        }

        sbp2_shost_template.max_sectors = sbp2_max_sectors;

        hpsb_register_highlevel(&sbp2_highlevel);
        ret = hpsb_register_protocol(&sbp2_driver);
        if (ret) {
                SBP2_ERR("Failed to register protocol");
                hpsb_unregister_highlevel(&sbp2_highlevel);
                return ret;
        }
        return 0;
}

static void __exit sbp2_module_exit(void)
{
        hpsb_unregister_protocol(&sbp2_driver);
        hpsb_unregister_highlevel(&sbp2_highlevel);
}

module_init(sbp2_module_init);
module_exit(sbp2_module_exit);