firewire: Only use INIT_DELAYED_WORK for first initialization.

[deliverable/linux.git] / drivers / firewire / fw-sbp2.c

/*                                              -*- c-basic-offset: 8 -*-
 * fw-spb2.c -- SBP2 driver (SCSI over IEEE1394)
 *
 * Copyright (C) 2005-2007  Kristian Hoegsberg <krh@bitplanet.net>
 *
 * 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.
 */

/* The basic structure of this driver is based the old storage driver,
 * drivers/ieee1394/sbp2.c, originally written by
 *     James Goodwin <jamesg@filanet.com>
 * with later contributions and ongoing maintenance from
 *     Ben Collins <bcollins@debian.org>,
 *     Stefan Richter <stefanr@s5r6.in-berlin.de>
 * and many others.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/device.h>
#include <linux/scatterlist.h>
#include <linux/dma-mapping.h>
#include <linux/timer.h>

#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 "fw-transaction.h"
#include "fw-topology.h"
#include "fw-device.h"

/* I don't know why the SCSI stack doesn't define something like this... */
typedef void (*scsi_done_fn_t) (struct scsi_cmnd *);

static const char sbp2_driver_name[] = "sbp2";

struct sbp2_device {
        struct fw_unit *unit;
        struct fw_address_handler address_handler;
        struct list_head orb_list;
        u64 management_agent_address;
        u64 command_block_agent_address;
        u32 workarounds;
        int login_id;

        /* We cache these addresses and only update them once we've
         * logged in or reconnected to the sbp2 device.  That way, any
         * IO to the device will automatically fail and get retried if
         * it happens in a window where the device is not ready to
         * handle it (e.g. after a bus reset but before we reconnect). */
        int node_id;
        int address_high;
        int generation;

        /* Timer for flushing ORBs. */
        struct timer_list orb_timer;

        int retries;
        struct delayed_work work;
        struct Scsi_Host *scsi_host;
};

#define SBP2_MAX_SG_ELEMENT_LENGTH      0xf000
#define SBP2_MAX_SECTORS                255     /* Max sectors supported */
#define SBP2_ORB_TIMEOUT                2000    /* Timeout in ms */

#define SBP2_ORB_NULL                   0x80000000

#define SBP2_DIRECTION_TO_MEDIA         0x0
#define SBP2_DIRECTION_FROM_MEDIA       0x1

/* Unit directory keys */
#define SBP2_COMMAND_SET_SPECIFIER      0x38
#define SBP2_COMMAND_SET                0x39
#define SBP2_COMMAND_SET_REVISION       0x3b
#define SBP2_FIRMWARE_REVISION          0x3c

/* Flags for detected oddities and brokeness */
#define SBP2_WORKAROUND_128K_MAX_TRANS  0x1
#define SBP2_WORKAROUND_INQUIRY_36      0x2
#define SBP2_WORKAROUND_MODE_SENSE_8    0x4
#define SBP2_WORKAROUND_FIX_CAPACITY    0x8
#define SBP2_WORKAROUND_OVERRIDE        0x100

/* Management orb opcodes */
#define SBP2_LOGIN_REQUEST              0x0
#define SBP2_QUERY_LOGINS_REQUEST       0x1
#define SBP2_RECONNECT_REQUEST          0x3
#define SBP2_SET_PASSWORD_REQUEST       0x4
#define SBP2_LOGOUT_REQUEST             0x7
#define SBP2_ABORT_TASK_REQUEST         0xb
#define SBP2_ABORT_TASK_SET             0xc
#define SBP2_LOGICAL_UNIT_RESET         0xe
#define SBP2_TARGET_RESET_REQUEST       0xf

/* Offsets for command block agent registers */
#define SBP2_AGENT_STATE                0x00
#define SBP2_AGENT_RESET                0x04
#define SBP2_ORB_POINTER                0x08
#define SBP2_DOORBELL                   0x10
#define SBP2_UNSOLICITED_STATUS_ENABLE  0x14

/* Status write response codes */
#define SBP2_STATUS_REQUEST_COMPLETE    0x0
#define SBP2_STATUS_TRANSPORT_FAILURE   0x1
#define SBP2_STATUS_ILLEGAL_REQUEST     0x2
#define SBP2_STATUS_VENDOR_DEPENDENT    0x3

#define status_get_orb_high(v)          ((v).status & 0xffff)
#define status_get_sbp_status(v)        (((v).status >> 16) & 0xff)
#define status_get_len(v)               (((v).status >> 24) & 0x07)
#define status_get_dead(v)              (((v).status >> 27) & 0x01)
#define status_get_response(v)          (((v).status >> 28) & 0x03)
#define status_get_source(v)            (((v).status >> 30) & 0x03)
#define status_get_orb_low(v)           ((v).orb_low)
#define status_get_data(v)              ((v).data)

struct sbp2_status {
        u32 status;
        u32 orb_low;
        u8 data[24];
};

struct sbp2_pointer {
        u32 high;
        u32 low;
};

struct sbp2_orb {
        struct fw_transaction t;
        dma_addr_t request_bus;
        int rcode;
        struct sbp2_pointer pointer;
        void (*callback) (struct sbp2_orb * orb, struct sbp2_status * status);
        struct list_head link;
};

#define management_orb_lun(v)                   ((v))
#define management_orb_function(v)              ((v) << 16)
#define management_orb_reconnect(v)             ((v) << 20)
#define management_orb_exclusive                ((1) << 28)
#define management_orb_request_format(v)        ((v) << 29)
#define management_orb_notify                   ((1) << 31)

#define management_orb_response_length(v)       ((v))
#define management_orb_password_length(v)       ((v) << 16)

struct sbp2_management_orb {
        struct sbp2_orb base;
        struct {
                struct sbp2_pointer password;
                struct sbp2_pointer response;
                u32 misc;
                u32 length;
                struct sbp2_pointer status_fifo;
        } request;
        __be32 response[4];
        dma_addr_t response_bus;
        struct completion done;
        struct sbp2_status status;
};

#define login_response_get_login_id(v)  ((v).misc & 0xffff)
#define login_response_get_length(v)    (((v).misc >> 16) & 0xffff)

struct sbp2_login_response {
        u32 misc;
        struct sbp2_pointer command_block_agent;
        u32 reconnect_hold;
};

#define command_orb_data_size(v)        ((v))
#define command_orb_page_size(v)        ((v) << 16)
#define command_orb_page_table_present  ((1) << 19)
#define command_orb_max_payload(v)      ((v) << 20)
#define command_orb_speed(v)            ((v) << 24)
#define command_orb_direction(v)        ((v) << 27)
#define command_orb_request_format(v)   ((v) << 29)
#define command_orb_notify              ((1) << 31)

struct sbp2_command_orb {
        struct sbp2_orb base;
        struct {
                struct sbp2_pointer next;
                struct sbp2_pointer data_descriptor;
                u32 misc;
                u8 command_block[12];
        } request;
        struct scsi_cmnd *cmd;
        scsi_done_fn_t done;
        struct fw_unit *unit;

        struct sbp2_pointer page_table[SG_ALL];
        dma_addr_t page_table_bus;
        dma_addr_t request_buffer_bus;
};

/*
 * 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.  We use ~0 as a wildcard, since the 24 bit values we get
 * from the config rom can never match that.
 */
static const struct {
        u32 firmware_revision;
        u32 model;
        unsigned workarounds;
} sbp2_workarounds_table[] = {
        /* DViCO Momobay CX-1 with TSB42AA9 bridge */ {
                .firmware_revision      = 0x002800,
                .model                  = 0x001010,
                .workarounds            = SBP2_WORKAROUND_INQUIRY_36 |
                                          SBP2_WORKAROUND_MODE_SENSE_8,
        },
        /* Initio bridges, actually only needed for some older ones */ {
                .firmware_revision      = 0x000200,
                .model                  = ~0,
                .workarounds            = SBP2_WORKAROUND_INQUIRY_36,
        },
        /* Symbios bridge */ {
                .firmware_revision      = 0xa0b800,
                .model                  = ~0,
                .workarounds            = SBP2_WORKAROUND_128K_MAX_TRANS,
        },
        /* There are iPods (2nd gen, 3rd gen) with model_id == 0, but
         * these iPods do not feature the read_capacity bug according
         * to one report.  Read_capacity behaviour as well as model_id
         * could change due to Apple-supplied firmware updates though. */
        /* iPod 4th generation. */ {
                .firmware_revision      = 0x0a2700,
                .model                  = 0x000021,
                .workarounds            = SBP2_WORKAROUND_FIX_CAPACITY,
        },
        /* iPod mini */ {
                .firmware_revision      = 0x0a2700,
                .model                  = 0x000023,
                .workarounds            = SBP2_WORKAROUND_FIX_CAPACITY,
        },
        /* iPod Photo */ {
                .firmware_revision      = 0x0a2700,
                .model                  = 0x00007e,
                .workarounds            = SBP2_WORKAROUND_FIX_CAPACITY,
        }
};

static void
sbp2_status_write(struct fw_card *card, struct fw_request *request,
                  int tcode, int destination, int source,
                  int generation, int speed,
                  unsigned long long offset,
                  void *payload, size_t length, void *callback_data)
{
        struct sbp2_device *sd = callback_data;
        struct sbp2_orb *orb;
        struct sbp2_status status;
        size_t header_size;
        unsigned long flags;

        if (tcode != TCODE_WRITE_BLOCK_REQUEST ||
            length == 0 || length > sizeof status) {
                fw_send_response(card, request, RCODE_TYPE_ERROR);
                return;
        }

        header_size = min(length, 2 * sizeof(u32));
        fw_memcpy_from_be32(&status, payload, header_size);
        if (length > header_size)
                memcpy(status.data, payload + 8, length - header_size);
        if (status_get_source(status) == 2 || status_get_source(status) == 3) {
                fw_notify("non-orb related status write, not handled\n");
                fw_send_response(card, request, RCODE_COMPLETE);
                return;
        }

        /* Lookup the orb corresponding to this status write. */
        spin_lock_irqsave(&card->lock, flags);
        list_for_each_entry(orb, &sd->orb_list, link) {
                if (status_get_orb_high(status) == 0 &&
                    status_get_orb_low(status) == orb->request_bus) {
                        list_del(&orb->link);
                        break;
                }
        }
        spin_unlock_irqrestore(&card->lock, flags);

        if (&orb->link != &sd->orb_list)
                orb->callback(orb, &status);
        else
                fw_error("status write for unknown orb\n");

        fw_send_response(card, request, RCODE_COMPLETE);
}

static void
complete_transaction(struct fw_card *card, int rcode,
                     void *payload, size_t length, void *data)
{
        struct sbp2_orb *orb = data;
        unsigned long flags;

        orb->rcode = rcode;
        if (rcode != RCODE_COMPLETE) {
                spin_lock_irqsave(&card->lock, flags);
                list_del(&orb->link);
                spin_unlock_irqrestore(&card->lock, flags);
                orb->callback(orb, NULL);
        }
}

static void
sbp2_send_orb(struct sbp2_orb *orb, struct fw_unit *unit,
              int node_id, int generation, u64 offset)
{
        struct fw_device *device = fw_device(unit->device.parent);
        struct sbp2_device *sd = unit->device.driver_data;
        unsigned long flags;

        orb->pointer.high = 0;
        orb->pointer.low = orb->request_bus;
        fw_memcpy_to_be32(&orb->pointer, &orb->pointer, sizeof orb->pointer);

        spin_lock_irqsave(&device->card->lock, flags);
        list_add_tail(&orb->link, &sd->orb_list);
        spin_unlock_irqrestore(&device->card->lock, flags);

        mod_timer(&sd->orb_timer,
                  jiffies + DIV_ROUND_UP(SBP2_ORB_TIMEOUT * HZ, 1000));

        fw_send_request(device->card, &orb->t, TCODE_WRITE_BLOCK_REQUEST,
                        node_id, generation,
                        device->node->max_speed, offset,
                        &orb->pointer, sizeof orb->pointer,
                        complete_transaction, orb);
}

static void sbp2_cancel_orbs(struct fw_unit *unit)
{
        struct fw_device *device = fw_device(unit->device.parent);
        struct sbp2_device *sd = unit->device.driver_data;
        struct sbp2_orb *orb, *next;
        struct list_head list;
        unsigned long flags;

        INIT_LIST_HEAD(&list);
        spin_lock_irqsave(&device->card->lock, flags);
        list_splice_init(&sd->orb_list, &list);
        spin_unlock_irqrestore(&device->card->lock, flags);

        list_for_each_entry_safe(orb, next, &list, link) {
                if (fw_cancel_transaction(device->card, &orb->t) == 0)
                        continue;

                orb->rcode = RCODE_CANCELLED;
                orb->callback(orb, NULL);
        }
}

static void orb_timer_callback(unsigned long data)
{
        struct sbp2_device *sd = (struct sbp2_device *)data;

        sbp2_cancel_orbs(sd->unit);
}

static void
complete_management_orb(struct sbp2_orb *base_orb, struct sbp2_status *status)
{
        struct sbp2_management_orb *orb =
            (struct sbp2_management_orb *)base_orb;

        if (status)
                memcpy(&orb->status, status, sizeof *status);
        complete(&orb->done);
}

static int
sbp2_send_management_orb(struct fw_unit *unit, int node_id, int generation,
                         int function, int lun, void *response)
{
        struct fw_device *device = fw_device(unit->device.parent);
        struct sbp2_device *sd = unit->device.driver_data;
        struct sbp2_management_orb *orb;
        int retval = -ENOMEM;

        orb = kzalloc(sizeof *orb, GFP_ATOMIC);
        if (orb == NULL)
                return -ENOMEM;

        /* The sbp2 device is going to send a block read request to
         * read out the request from host memory, so map it for
         * dma. */
        orb->base.request_bus =
                dma_map_single(device->card->device, &orb->request,
                               sizeof orb->request, DMA_TO_DEVICE);
        if (dma_mapping_error(orb->base.request_bus))
                goto out;

        orb->response_bus =
                dma_map_single(device->card->device, &orb->response,
                               sizeof orb->response, DMA_FROM_DEVICE);
        if (dma_mapping_error(orb->response_bus))
                goto out;

        orb->request.response.high    = 0;
        orb->request.response.low     = orb->response_bus;

        orb->request.misc =
                management_orb_notify |
                management_orb_function(function) |
                management_orb_lun(lun);
        orb->request.length =
                management_orb_response_length(sizeof orb->response);

        orb->request.status_fifo.high = sd->address_handler.offset >> 32;
        orb->request.status_fifo.low  = sd->address_handler.offset;

        /* FIXME: Yeah, ok this isn't elegant, we hardwire exclusive
         * login and 1 second reconnect time.  The reconnect setting
         * is probably fine, but the exclusive login should be an
         * option. */
        if (function == SBP2_LOGIN_REQUEST) {
                orb->request.misc |=
                        management_orb_exclusive |
                        management_orb_reconnect(0);
        }

        fw_memcpy_to_be32(&orb->request, &orb->request, sizeof orb->request);

        init_completion(&orb->done);
        orb->base.callback = complete_management_orb;
        sbp2_send_orb(&orb->base, unit,
                      node_id, generation, sd->management_agent_address);

        wait_for_completion(&orb->done);

        /* FIXME: Handle bus reset race here. */

        retval = -EIO;
        if (orb->base.rcode != RCODE_COMPLETE) {
                fw_error("management write failed, rcode 0x%02x\n",
                         orb->base.rcode);
                goto out;
        }

        if (orb->base.rcode == RCODE_CANCELLED) {
                fw_error("orb reply timed out, rcode=0x%02x\n",
                         orb->base.rcode);
                goto out;
        }

        if (status_get_response(orb->status) != 0 ||
            status_get_sbp_status(orb->status) != 0) {
                fw_error("error status: %d:%d\n",
                         status_get_response(orb->status),
                         status_get_sbp_status(orb->status));
                goto out;
        }

        retval = 0;
 out:
        dma_unmap_single(device->card->device, orb->base.request_bus,
                         sizeof orb->request, DMA_TO_DEVICE);
        dma_unmap_single(device->card->device, orb->response_bus,
                         sizeof orb->response, DMA_FROM_DEVICE);

        if (response)
                fw_memcpy_from_be32(response,
                                    orb->response, sizeof orb->response);
        kfree(orb);

        return retval;
}

static void
complete_agent_reset_write(struct fw_card *card, int rcode,
                           void *payload, size_t length, void *data)
{
        struct fw_transaction *t = data;

        fw_notify("agent reset write rcode=%d\n", rcode);
        kfree(t);
}

static int sbp2_agent_reset(struct fw_unit *unit)
{
        struct fw_device *device = fw_device(unit->device.parent);
        struct sbp2_device *sd = unit->device.driver_data;
        struct fw_transaction *t;
        static u32 zero;

        t = kzalloc(sizeof *t, GFP_ATOMIC);
        if (t == NULL)
                return -ENOMEM;

        fw_send_request(device->card, t, TCODE_WRITE_QUADLET_REQUEST,
                        sd->node_id, sd->generation, SCODE_400,
                        sd->command_block_agent_address + SBP2_AGENT_RESET,
                        &zero, sizeof zero, complete_agent_reset_write, t);

        return 0;
}

static int add_scsi_devices(struct fw_unit *unit);
static void remove_scsi_devices(struct fw_unit *unit);
static void sbp2_reconnect(struct work_struct *work);

static void sbp2_login(struct work_struct *work)
{
        struct sbp2_device *sd =
                container_of(work, struct sbp2_device, work.work);
        struct fw_unit *unit = sd->unit;
        struct fw_device *device = fw_device(unit->device.parent);
        struct sbp2_login_response response;
        int generation, node_id, local_node_id, lun, retval;

        /* FIXME: Make this work for multi-lun devices. */
        lun = 0;

        generation    = device->card->generation;
        node_id       = device->node->node_id;
        local_node_id = device->card->local_node->node_id;

        if (sbp2_send_management_orb(unit, node_id, generation,
                                     SBP2_LOGIN_REQUEST, lun, &response) < 0) {
                if (sd->retries++ < 5) {
                        fw_error("login attempt %d for %s failed, "
                                 "rescheduling\n",
                                 sd->retries, unit->device.bus_id);
                        schedule_delayed_work(&sd->work, DIV_ROUND_UP(HZ, 5));
                } else {
                        fw_error("failed to login to %s\n",
                                 unit->device.bus_id);
                        remove_scsi_devices(unit);
                }
                return;
        }

        sd->generation   = generation;
        sd->node_id      = node_id;
        sd->address_high = local_node_id << 16;

        /* Get command block agent offset and login id. */
        sd->command_block_agent_address =
                ((u64) response.command_block_agent.high << 32) |
                response.command_block_agent.low;
        sd->login_id = login_response_get_login_id(response);

        fw_notify("logged in to sbp2 unit %s\n", unit->device.bus_id);
        fw_notify(" - management_agent_address: 0x%012llx\n",
                  (unsigned long long) sd->management_agent_address);
        fw_notify(" - command_block_agent_address: 0x%012llx\n",
                  (unsigned long long) sd->command_block_agent_address);
        fw_notify(" - status write address: 0x%012llx\n",
                  (unsigned long long) sd->address_handler.offset);

#if 0
        /* FIXME: The linux1394 sbp2 does this last step. */
        sbp2_set_busy_timeout(scsi_id);
#endif

        PREPARE_DELAYED_WORK(&sd->work, sbp2_reconnect);
        sbp2_agent_reset(unit);

        retval = add_scsi_devices(unit);
        if (retval < 0) {
                sbp2_send_management_orb(unit, sd->node_id, sd->generation,
                                         SBP2_LOGOUT_REQUEST, sd->login_id,
                                         NULL);
                /* Set this back to sbp2_login so we fall back and
                 * retry login on bus reset. */
                PREPARE_DELAYED_WORK(&sd->work, sbp2_login);
        }
}

static int sbp2_probe(struct device *dev)
{
        struct fw_unit *unit = fw_unit(dev);
        struct fw_device *device = fw_device(unit->device.parent);
        struct sbp2_device *sd;
        struct fw_csr_iterator ci;
        int i, key, value;
        u32 model, firmware_revision;

        sd = kzalloc(sizeof *sd, GFP_KERNEL);
        if (sd == NULL)
                return -ENOMEM;

        unit->device.driver_data = sd;
        sd->unit = unit;
        INIT_LIST_HEAD(&sd->orb_list);
        setup_timer(&sd->orb_timer, orb_timer_callback, (unsigned long)sd);

        sd->address_handler.length = 0x100;
        sd->address_handler.address_callback = sbp2_status_write;
        sd->address_handler.callback_data = sd;

        if (fw_core_add_address_handler(&sd->address_handler,
                                        &fw_high_memory_region) < 0) {
                kfree(sd);
                return -EBUSY;
        }

        if (fw_device_enable_phys_dma(device) < 0) {
                fw_core_remove_address_handler(&sd->address_handler);
                kfree(sd);
                return -EBUSY;
        }

        /* Scan unit directory to get management agent address,
         * firmware revison and model.  Initialize firmware_revision
         * and model to values that wont match anything in our table. */
        firmware_revision = 0xff000000;
        model = 0xff000000;
        fw_csr_iterator_init(&ci, unit->directory);
        while (fw_csr_iterator_next(&ci, &key, &value)) {
                switch (key) {
                case CSR_DEPENDENT_INFO | CSR_OFFSET:
                        sd->management_agent_address =
                                0xfffff0000000ULL + 4 * value;
                        break;
                case SBP2_FIRMWARE_REVISION:
                        firmware_revision = value;
                        break;
                case CSR_MODEL:
                        model = value;
                        break;
                }
        }

        for (i = 0; i < ARRAY_SIZE(sbp2_workarounds_table); i++) {
                if (sbp2_workarounds_table[i].firmware_revision !=
                    (firmware_revision & 0xffffff00))
                        continue;
                if (sbp2_workarounds_table[i].model != model &&
                    sbp2_workarounds_table[i].model != ~0)
                        continue;
                sd->workarounds |= sbp2_workarounds_table[i].workarounds;
                break;
        }

        if (sd->workarounds)
                fw_notify("Workarounds for node %s: 0x%x "
                          "(firmware_revision 0x%06x, model_id 0x%06x)\n",
                          unit->device.bus_id,
                          sd->workarounds, firmware_revision, model);

        /* We schedule work to do the login so we can easily
         * reschedule retries. */
        INIT_DELAYED_WORK(&sd->work, sbp2_login);
        schedule_delayed_work(&sd->work, 0);

        return 0;
}

static int sbp2_remove(struct device *dev)
{
        struct fw_unit *unit = fw_unit(dev);
        struct sbp2_device *sd = unit->device.driver_data;

        sbp2_send_management_orb(unit, sd->node_id, sd->generation,
                                 SBP2_LOGOUT_REQUEST, sd->login_id, NULL);

        remove_scsi_devices(unit);
        del_timer_sync(&sd->orb_timer);

        fw_core_remove_address_handler(&sd->address_handler);
        kfree(sd);

        fw_notify("removed sbp2 unit %s\n", dev->bus_id);

        return 0;
}

static void sbp2_reconnect(struct work_struct *work)
{
        struct sbp2_device *sd =
                container_of(work, struct sbp2_device, work.work);
        struct fw_unit *unit = sd->unit;
        struct fw_device *device = fw_device(unit->device.parent);
        int generation, node_id, local_node_id;

        generation    = device->card->generation;
        node_id       = device->node->node_id;
        local_node_id = device->card->local_node->node_id;

        if (sbp2_send_management_orb(unit, node_id, generation,
                                     SBP2_RECONNECT_REQUEST,
                                     sd->login_id, NULL) < 0) {
                if (sd->retries++ < 5) {
                        fw_error("reconnect attempt %d for %s failed, "
                                 "rescheduling\n",
                                 sd->retries, unit->device.bus_id);
                } else {
                        fw_error("failed to reconnect to %s\n",
                                 unit->device.bus_id);
                        /* Fall back and try to log in again. */
                        sd->retries = 0;
                        PREPARE_DELAYED_WORK(&sd->work, sbp2_login);
                }
                schedule_delayed_work(&sd->work, DIV_ROUND_UP(HZ, 5));
                return;
        }

        sd->generation   = generation;
        sd->node_id      = node_id;
        sd->address_high = local_node_id << 16;

        fw_notify("reconnected to unit %s\n", unit->device.bus_id);
        sbp2_agent_reset(unit);
        sbp2_cancel_orbs(unit);
}

static void sbp2_update(struct fw_unit *unit)
{
        struct fw_device *device = fw_device(unit->device.parent);
        struct sbp2_device *sd = unit->device.driver_data;

        sd->retries = 0;
        fw_device_enable_phys_dma(device);
        schedule_delayed_work(&sd->work, 0);
}

#define SBP2_UNIT_SPEC_ID_ENTRY 0x0000609e
#define SBP2_SW_VERSION_ENTRY   0x00010483

static const struct fw_device_id sbp2_id_table[] = {
        {
                .match_flags  = FW_MATCH_SPECIFIER_ID | FW_MATCH_VERSION,
                .specifier_id = SBP2_UNIT_SPEC_ID_ENTRY,
                .version      = SBP2_SW_VERSION_ENTRY,
        },
        { }
};

static struct fw_driver sbp2_driver = {
        .driver   = {
                .owner  = THIS_MODULE,
                .name   = sbp2_driver_name,
                .bus    = &fw_bus_type,
                .probe  = sbp2_probe,
                .remove = sbp2_remove,
        },
        .update   = sbp2_update,
        .id_table = sbp2_id_table,
};

static unsigned int sbp2_status_to_sense_data(u8 * sbp2_status, u8 * sense_data)
{
        sense_data[0] = 0x70;
        sense_data[1] = 0x0;
        sense_data[2] = sbp2_status[1];
        sense_data[3] = sbp2_status[4];
        sense_data[4] = sbp2_status[5];
        sense_data[5] = sbp2_status[6];
        sense_data[6] = sbp2_status[7];
        sense_data[7] = 10;
        sense_data[8] = sbp2_status[8];
        sense_data[9] = sbp2_status[9];
        sense_data[10] = sbp2_status[10];
        sense_data[11] = sbp2_status[11];
        sense_data[12] = sbp2_status[2];
        sense_data[13] = sbp2_status[3];
        sense_data[14] = sbp2_status[12];
        sense_data[15] = sbp2_status[13];

        switch (sbp2_status[0] & 0x3f) {
        case SAM_STAT_GOOD:
                return DID_OK;

        case SAM_STAT_CHECK_CONDITION:
                /* return CHECK_CONDITION << 1 | DID_OK << 16; */
                return DID_OK;

        case SAM_STAT_BUSY:
                return DID_BUS_BUSY;

        case SAM_STAT_CONDITION_MET:
        case SAM_STAT_RESERVATION_CONFLICT:
        case SAM_STAT_COMMAND_TERMINATED:
        default:
                return DID_ERROR;
        }
}

static void
complete_command_orb(struct sbp2_orb *base_orb, struct sbp2_status *status)
{
        struct sbp2_command_orb *orb = (struct sbp2_command_orb *)base_orb;
        struct fw_unit *unit = orb->unit;
        struct fw_device *device = fw_device(unit->device.parent);
        struct scatterlist *sg;
        int result;

        if (status != NULL) {
                if (status_get_dead(*status)) {
                        fw_notify("agent died, issuing agent reset\n");
                        sbp2_agent_reset(unit);
                }

                switch (status_get_response(*status)) {
                case SBP2_STATUS_REQUEST_COMPLETE:
                        result = DID_OK;
                        break;
                case SBP2_STATUS_TRANSPORT_FAILURE:
                        result = DID_BUS_BUSY;
                        break;
                case SBP2_STATUS_ILLEGAL_REQUEST:
                case SBP2_STATUS_VENDOR_DEPENDENT:
                default:
                        result = DID_ERROR;
                        break;
                }

                if (result == DID_OK && status_get_len(*status) > 1)
                        result = sbp2_status_to_sense_data(status_get_data(*status),
                                                           orb->cmd->sense_buffer);
        } else {
                /* If the orb completes with status == NULL, something
                 * went wrong, typically a bus reset happened mid-orb
                 * or when sending the write (less likely). */
                fw_notify("no command orb status, rcode=%d\n",
                          orb->base.rcode);
                result = DID_BUS_BUSY;
        }

        dma_unmap_single(device->card->device, orb->base.request_bus,
                         sizeof orb->request, DMA_TO_DEVICE);

        if (orb->cmd->use_sg > 0) {
                sg = (struct scatterlist *)orb->cmd->request_buffer;
                dma_unmap_sg(device->card->device, sg, orb->cmd->use_sg,
                             orb->cmd->sc_data_direction);
        }

        if (orb->page_table_bus != 0)
                dma_unmap_single(device->card->device, orb->page_table_bus,
                                 sizeof orb->page_table_bus, DMA_TO_DEVICE);

        if (orb->request_buffer_bus != 0)
                dma_unmap_single(device->card->device, orb->request_buffer_bus,
                                 sizeof orb->request_buffer_bus,
                                 DMA_FROM_DEVICE);

        orb->cmd->result = result << 16;
        orb->done(orb->cmd);

        kfree(orb);
}

static void sbp2_command_orb_map_scatterlist(struct sbp2_command_orb *orb)
{
        struct fw_unit *unit =
                (struct fw_unit *)orb->cmd->device->host->hostdata[0];
        struct fw_device *device = fw_device(unit->device.parent);
        struct sbp2_device *sd = unit->device.driver_data;
        struct scatterlist *sg;
        int sg_len, l, i, j, count;
        size_t size;
        dma_addr_t sg_addr;

        sg = (struct scatterlist *)orb->cmd->request_buffer;
        count = dma_map_sg(device->card->device, sg, orb->cmd->use_sg,
                           orb->cmd->sc_data_direction);

        /* Handle the special case where there is only one element in
         * the scatter list by converting it to an immediate block
         * request. This is also a workaround for broken devices such
         * as the second generation iPod which doesn't support page
         * tables. */
        if (count == 1 && sg_dma_len(sg) < SBP2_MAX_SG_ELEMENT_LENGTH) {
                orb->request.data_descriptor.high = sd->address_high;
                orb->request.data_descriptor.low  = sg_dma_address(sg);
                orb->request.misc |=
                        command_orb_data_size(sg_dma_len(sg));
                return;
        }

        /* Convert the scatterlist to an sbp2 page table.  If any
         * scatterlist entries are too big for sbp2 we split the as we go. */
        for (i = 0, j = 0; i < count; i++) {
                sg_len = sg_dma_len(sg + i);
                sg_addr = sg_dma_address(sg + i);
                while (sg_len) {
                        l = min(sg_len, SBP2_MAX_SG_ELEMENT_LENGTH);
                        orb->page_table[j].low = sg_addr;
                        orb->page_table[j].high = (l << 16);
                        sg_addr += l;
                        sg_len -= l;
                        j++;
                }
        }

        size = sizeof orb->page_table[0] * j;

        /* The data_descriptor pointer is the one case where we need
         * to fill in the node ID part of the address.  All other
         * pointers assume that the data referenced reside on the
         * initiator (i.e. us), but data_descriptor can refer to data
         * on other nodes so we need to put our ID in descriptor.high. */

        orb->page_table_bus =
                dma_map_single(device->card->device, orb->page_table,
                               size, DMA_TO_DEVICE);
        orb->request.data_descriptor.high = sd->address_high;
        orb->request.data_descriptor.low  = orb->page_table_bus;
        orb->request.misc |=
                command_orb_page_table_present |
                command_orb_data_size(j);

        fw_memcpy_to_be32(orb->page_table, orb->page_table, size);
}

static void sbp2_command_orb_map_buffer(struct sbp2_command_orb *orb)
{
        struct fw_unit *unit =
                (struct fw_unit *)orb->cmd->device->host->hostdata[0];
        struct fw_device *device = fw_device(unit->device.parent);
        struct sbp2_device *sd = unit->device.driver_data;

        /* As for map_scatterlist, we need to fill in the high bits of
         * the data_descriptor pointer. */

        orb->request_buffer_bus =
                dma_map_single(device->card->device,
                               orb->cmd->request_buffer,
                               orb->cmd->request_bufflen,
                               orb->cmd->sc_data_direction);
        orb->request.data_descriptor.high = sd->address_high;
        orb->request.data_descriptor.low  = orb->request_buffer_bus;
        orb->request.misc |=
                command_orb_data_size(orb->cmd->request_bufflen);
}

/* SCSI stack integration */

static int sbp2_scsi_queuecommand(struct scsi_cmnd *cmd, scsi_done_fn_t done)
{
        struct fw_unit *unit = (struct fw_unit *)cmd->device->host->hostdata[0];
        struct fw_device *device = fw_device(unit->device.parent);
        struct sbp2_device *sd = unit->device.driver_data;
        struct sbp2_command_orb *orb;

        /* Bidirectional commands are not yet implemented, and unknown
         * transfer direction not handled. */
        if (cmd->sc_data_direction == DMA_BIDIRECTIONAL) {
                fw_error("Cannot handle DMA_BIDIRECTIONAL - rejecting command");
                goto fail_alloc;
        }

        orb = kzalloc(sizeof *orb, GFP_ATOMIC);
        if (orb == NULL) {
                fw_notify("failed to alloc orb\n");
                goto fail_alloc;
        }

        orb->base.request_bus =
                dma_map_single(device->card->device, &orb->request,
                               sizeof orb->request, DMA_TO_DEVICE);
        if (dma_mapping_error(orb->base.request_bus))
                goto fail_mapping;

        orb->unit = unit;
        orb->done = done;
        orb->cmd  = cmd;

        orb->request.next.high   = SBP2_ORB_NULL;
        orb->request.next.low    = 0x0;
        /* At speed 100 we can do 512 bytes per packet, at speed 200,
         * 1024 bytes per packet etc.  The SBP-2 max_payload field
         * specifies the max payload size as 2 ^ (max_payload + 2), so
         * if we set this to max_speed + 7, we get the right value. */
        orb->request.misc =
                command_orb_max_payload(device->node->max_speed + 7) |
                command_orb_speed(device->node->max_speed) |
                command_orb_notify;

        if (cmd->sc_data_direction == DMA_FROM_DEVICE)
                orb->request.misc |=
                        command_orb_direction(SBP2_DIRECTION_FROM_MEDIA);
        else if (cmd->sc_data_direction == DMA_TO_DEVICE)
                orb->request.misc |=
                        command_orb_direction(SBP2_DIRECTION_TO_MEDIA);

        if (cmd->use_sg) {
                sbp2_command_orb_map_scatterlist(orb);
        } else if (cmd->request_bufflen > SBP2_MAX_SG_ELEMENT_LENGTH) {
                /* FIXME: Need to split this into a sg list... but
                 * could we get the scsi or blk layer to do that by
                 * reporting our max supported block size? */
                fw_error("command > 64k\n");
                goto fail_bufflen;
        } else if (cmd->request_bufflen > 0) {
                sbp2_command_orb_map_buffer(orb);
        }

        fw_memcpy_to_be32(&orb->request, &orb->request, sizeof orb->request);

        memset(orb->request.command_block,
               0, sizeof orb->request.command_block);
        memcpy(orb->request.command_block, cmd->cmnd, COMMAND_SIZE(*cmd->cmnd));

        orb->base.callback = complete_command_orb;

        sbp2_send_orb(&orb->base, unit, sd->node_id, sd->generation,
                      sd->command_block_agent_address + SBP2_ORB_POINTER);

        return 0;

 fail_bufflen:
        dma_unmap_single(device->card->device, orb->base.request_bus,
                         sizeof orb->request, DMA_TO_DEVICE);
 fail_mapping:
        kfree(orb);
 fail_alloc:
        cmd->result = DID_ERROR << 16;
        done(cmd);
        return 0;
}

static int sbp2_scsi_slave_alloc(struct scsi_device *sdev)
{
        struct fw_unit *unit = (struct fw_unit *)sdev->host->hostdata[0];
        struct sbp2_device *sd = unit->device.driver_data;

        sdev->allow_restart = 1;

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

static int sbp2_scsi_slave_configure(struct scsi_device *sdev)
{
        struct fw_unit *unit = (struct fw_unit *)sdev->host->hostdata[0];
        struct sbp2_device *sd = unit->device.driver_data;

        sdev->use_10_for_rw = 1;

        if (sdev->type == TYPE_ROM)
                sdev->use_10_for_ms = 1;
        if (sdev->type == TYPE_DISK &&
            sd->workarounds & SBP2_WORKAROUND_MODE_SENSE_8)
                sdev->skip_ms_page_8 = 1;
        if (sd->workarounds & SBP2_WORKAROUND_FIX_CAPACITY) {
                fw_notify("setting fix_capacity for %s\n", unit->device.bus_id);
                sdev->fix_capacity = 1;
        }

        return 0;
}

/*
 * Called by scsi stack when something has really gone wrong.  Usually
 * called when a command has timed-out for some reason.
 */
static int sbp2_scsi_abort(struct scsi_cmnd *cmd)
{
        struct fw_unit *unit = (struct fw_unit *)cmd->device->host->hostdata[0];

        fw_notify("sbp2_scsi_abort\n");

        sbp2_cancel_orbs(unit);

        return SUCCESS;
}

static struct scsi_host_template scsi_driver_template = {
        .module                 = THIS_MODULE,
        .name                   = "SBP-2 IEEE-1394",
        .proc_name              = (char *)sbp2_driver_name,
        .queuecommand           = sbp2_scsi_queuecommand,
        .slave_alloc            = sbp2_scsi_slave_alloc,
        .slave_configure        = sbp2_scsi_slave_configure,
        .eh_abort_handler       = sbp2_scsi_abort,
        .this_id                = -1,
        .sg_tablesize           = SG_ALL,
        .use_clustering         = ENABLE_CLUSTERING,
        .cmd_per_lun            = 1,
        .can_queue              = 1,
};

static int add_scsi_devices(struct fw_unit *unit)
{
        struct sbp2_device *sd = unit->device.driver_data;
        int retval, lun;

        if (sd->scsi_host != NULL)
                return 0;

        sd->scsi_host = scsi_host_alloc(&scsi_driver_template,
                                        sizeof(unsigned long));
        if (sd->scsi_host == NULL) {
                fw_error("failed to register scsi host\n");
                return -1;
        }

        sd->scsi_host->hostdata[0] = (unsigned long)unit;
        retval = scsi_add_host(sd->scsi_host, &unit->device);
        if (retval < 0) {
                fw_error("failed to add scsi host\n");
                scsi_host_put(sd->scsi_host);
                return retval;
        }

        /* FIXME: Loop over luns here. */
        lun = 0;
        retval = scsi_add_device(sd->scsi_host, 0, 0, lun);
        if (retval < 0) {
                fw_error("failed to add scsi device\n");
                scsi_remove_host(sd->scsi_host);
                scsi_host_put(sd->scsi_host);
                return retval;
        }

        return 0;
}

static void remove_scsi_devices(struct fw_unit *unit)
{
        struct sbp2_device *sd = unit->device.driver_data;

        if (sd->scsi_host != NULL) {
                scsi_remove_host(sd->scsi_host);
                scsi_host_put(sd->scsi_host);
        }
        sd->scsi_host = NULL;
}

MODULE_AUTHOR("Kristian Hoegsberg <krh@bitplanet.net>");
MODULE_DESCRIPTION("SCSI over IEEE1394");
MODULE_LICENSE("GPL");
MODULE_DEVICE_TABLE(ieee1394, sbp2_id_table);

static int __init sbp2_init(void)
{
        return driver_register(&sbp2_driver.driver);
}

static void __exit sbp2_cleanup(void)
{
        driver_unregister(&sbp2_driver.driver);
}

module_init(sbp2_init);
module_exit(sbp2_cleanup);