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fw-sbp2.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 on 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/moduleparam.h>
#include <linux/mod_devicetable.h>
#include <linux/device.h>
#include <linux/scatterlist.h>
#include <linux/dma-mapping.h>
#include <linux/blkdev.h>
#include <linux/string.h>
#include <linux/stringify.h>
#include <linux/timer.h>
#include <linux/workqueue.h>

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

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

/*
 * 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.
 *
 * Concurrent logins are useful together with cluster filesystems.
 */
static int sbp2_param_exclusive_login = 1;
module_param_named(exclusive_login, sbp2_param_exclusive_login, bool, 0644);
MODULE_PARM_DESC(exclusive_login, "Exclusive login to sbp2 device "
             "(default = Y, use N for concurrent initiators)");

/*
 * Flags for firmware oddities
 *
 * - 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.
 *
 * - 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.
 */
#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

static int sbp2_param_workarounds;
module_param_named(workarounds, sbp2_param_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)
      ", override internal blacklist = " __stringify(SBP2_WORKAROUND_OVERRIDE)
      ", or a combination)");

/* 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";

/*
 * We create one struct sbp2_logical_unit per SBP-2 Logical Unit Number Entry
 * and one struct scsi_device per sbp2_logical_unit.
 */
struct sbp2_logical_unit {
      struct sbp2_target *tgt;
      struct list_head link;
      struct scsi_device *sdev;
      struct fw_address_handler address_handler;
      struct list_head orb_list;

      u64 command_block_agent_address;
      u16 lun;
      int login_id;

      /*
       * The generation is updated once we've logged in or reconnected
       * to the logical unit.  Thus, I/O to the device will automatically
       * fail and get retried if it happens in a window where the device
       * is not ready, e.g. after a bus reset but before we reconnect.
       */
      int generation;
      int retries;
      struct delayed_work work;
};

/*
 * We create one struct sbp2_target per IEEE 1212 Unit Directory
 * and one struct Scsi_Host per sbp2_target.
 */
struct sbp2_target {
      struct kref kref;
      struct fw_unit *unit;

      u64 management_agent_address;
      int directory_id;
      int node_id;
      int address_high;

      unsigned workarounds;
      struct list_head lu_list;
};

#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_CSR_FIRMWARE_REVISION  0x3c
#define SBP2_CSR_LOGICAL_UNIT_NUMBER      0x14
#define SBP2_CSR_LOGICAL_UNIT_DIRECTORY   0xd4

/* 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;
      struct kref kref;
      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(v)       ((v) ? 1 << 28 : 0)
#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 sbp2_logical_unit *lu;

      struct sbp2_pointer page_table[SG_ALL] __attribute__((aligned(8)));
      dma_addr_t page_table_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
free_orb(struct kref *kref)
{
      struct sbp2_orb *orb = container_of(kref, struct sbp2_orb, kref);

      kfree(orb);
}

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_logical_unit *lu = 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, &lu->orb_list, link) {
            if (STATUS_GET_ORB_HIGH(status) == 0 &&
                STATUS_GET_ORB_LOW(status) == orb->request_bus) {
                  orb->rcode = RCODE_COMPLETE;
                  list_del(&orb->link);
                  break;
            }
      }
      spin_unlock_irqrestore(&card->lock, flags);

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

      kref_put(&orb->kref, free_orb);

      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;

      /*
       * This is a little tricky.  We can get the status write for
       * the orb before we get this callback.  The status write
       * handler above will assume the orb pointer transaction was
       * successful and set the rcode to RCODE_COMPLETE for the orb.
       * So this callback only sets the rcode if it hasn't already
       * been set and only does the cleanup if the transaction
       * failed and we didn't already get a status write.
       */
      spin_lock_irqsave(&card->lock, flags);

      if (orb->rcode == -1)
            orb->rcode = rcode;
      if (orb->rcode != RCODE_COMPLETE) {
            list_del(&orb->link);
            spin_unlock_irqrestore(&card->lock, flags);
            orb->callback(orb, NULL);
      } else {
            spin_unlock_irqrestore(&card->lock, flags);
      }

      kref_put(&orb->kref, free_orb);
}

static void
sbp2_send_orb(struct sbp2_orb *orb, struct sbp2_logical_unit *lu,
            int node_id, int generation, u64 offset)
{
      struct fw_device *device = fw_device(lu->tgt->unit->device.parent);
      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, &lu->orb_list);
      spin_unlock_irqrestore(&device->card->lock, flags);

      /* Take a ref for the orb list and for the transaction callback. */
      kref_get(&orb->kref);
      kref_get(&orb->kref);

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

static int sbp2_cancel_orbs(struct sbp2_logical_unit *lu)
{
      struct fw_device *device = fw_device(lu->tgt->unit->device.parent);
      struct sbp2_orb *orb, *next;
      struct list_head list;
      unsigned long flags;
      int retval = -ENOENT;

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

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

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

      return retval;
}

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

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

static int
sbp2_send_management_orb(struct sbp2_logical_unit *lu, int node_id,
                   int generation, int function, int lun_or_login_id,
                   void *response)
{
      struct fw_device *device = fw_device(lu->tgt->unit->device.parent);
      struct sbp2_management_orb *orb;
      int retval = -ENOMEM;

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

      kref_init(&orb->base.kref);
      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 fail_mapping_response;

      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_or_login_id);
      orb->request.length =
            MANAGEMENT_ORB_RESPONSE_LENGTH(sizeof(orb->response));

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

      if (function == SBP2_LOGIN_REQUEST) {
            orb->request.misc |=
                  MANAGEMENT_ORB_EXCLUSIVE(sbp2_param_exclusive_login) |
                  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;

      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_request;

      sbp2_send_orb(&orb->base, lu, node_id, generation,
                  lu->tgt->management_agent_address);

      wait_for_completion_timeout(&orb->done,
                            msecs_to_jiffies(SBP2_ORB_TIMEOUT));

      retval = -EIO;
      if (sbp2_cancel_orbs(lu) == 0) {
            fw_error("orb reply timed out, rcode=0x%02x\n",
                   orb->base.rcode);
            goto out;
      }

      if (orb->base.rcode != RCODE_COMPLETE) {
            fw_error("management write failed, 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);
 fail_mapping_request:
      dma_unmap_single(device->card->device, orb->response_bus,
                   sizeof(orb->response), DMA_FROM_DEVICE);
 fail_mapping_response:
      if (response)
            fw_memcpy_from_be32(response,
                            orb->response, sizeof(orb->response));
      kref_put(&orb->base.kref, free_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;

      kfree(t);
}

static int sbp2_agent_reset(struct sbp2_logical_unit *lu)
{
      struct fw_device *device = fw_device(lu->tgt->unit->device.parent);
      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,
                  lu->tgt->node_id, lu->generation, device->max_speed,
                  lu->command_block_agent_address + SBP2_AGENT_RESET,
                  &zero, sizeof(zero), complete_agent_reset_write, t);

      return 0;
}

static void sbp2_release_target(struct kref *kref)
{
      struct sbp2_target *tgt = container_of(kref, struct sbp2_target, kref);
      struct sbp2_logical_unit *lu, *next;
      struct Scsi_Host *shost =
            container_of((void *)tgt, struct Scsi_Host, hostdata[0]);

      list_for_each_entry_safe(lu, next, &tgt->lu_list, link) {
            if (lu->sdev)
                  scsi_remove_device(lu->sdev);

            sbp2_send_management_orb(lu, tgt->node_id, lu->generation,
                        SBP2_LOGOUT_REQUEST, lu->login_id, NULL);
            fw_core_remove_address_handler(&lu->address_handler);
            list_del(&lu->link);
            kfree(lu);
      }
      scsi_remove_host(shost);
      fw_notify("released %s\n", tgt->unit->device.bus_id);

      put_device(&tgt->unit->device);
      scsi_host_put(shost);
}

static struct workqueue_struct *sbp2_wq;

static void sbp2_reconnect(struct work_struct *work);

static void sbp2_login(struct work_struct *work)
{
      struct sbp2_logical_unit *lu =
            container_of(work, struct sbp2_logical_unit, work.work);
      struct Scsi_Host *shost =
            container_of((void *)lu->tgt, struct Scsi_Host, hostdata[0]);
      struct scsi_device *sdev;
      struct scsi_lun eight_bytes_lun;
      struct fw_unit *unit = lu->tgt->unit;
      struct fw_device *device = fw_device(unit->device.parent);
      struct sbp2_login_response response;
      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(lu, node_id, generation,
                        SBP2_LOGIN_REQUEST, lu->lun, &response) < 0) {
            if (lu->retries++ < 5) {
                  if (queue_delayed_work(sbp2_wq, &lu->work,
                                     DIV_ROUND_UP(HZ, 5)))
                        kref_get(&lu->tgt->kref);
            } else {
                  fw_error("failed to login to %s LUN %04x\n",
                         unit->device.bus_id, lu->lun);
            }
            kref_put(&lu->tgt->kref, sbp2_release_target);
            return;
      }

      lu->generation        = generation;
      lu->tgt->node_id      = node_id;
      lu->tgt->address_high = local_node_id << 16;

      /* Get command block agent offset and login id. */
      lu->command_block_agent_address =
            ((u64) (response.command_block_agent.high & 0xffff) << 32) |
            response.command_block_agent.low;
      lu->login_id = LOGIN_RESPONSE_GET_LOGIN_ID(response);

      fw_notify("logged in to %s LUN %04x (%d retries)\n",
              unit->device.bus_id, lu->lun, lu->retries);

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

      PREPARE_DELAYED_WORK(&lu->work, sbp2_reconnect);
      sbp2_agent_reset(lu);

      memset(&eight_bytes_lun, 0, sizeof(eight_bytes_lun));
      eight_bytes_lun.scsi_lun[0] = (lu->lun >> 8) & 0xff;
      eight_bytes_lun.scsi_lun[1] = lu->lun & 0xff;

      sdev = __scsi_add_device(shost, 0, 0,
                         scsilun_to_int(&eight_bytes_lun), lu);
      if (IS_ERR(sdev)) {
            sbp2_send_management_orb(lu, node_id, generation,
                        SBP2_LOGOUT_REQUEST, lu->login_id, NULL);
            /*
             * Set this back to sbp2_login so we fall back and
             * retry login on bus reset.
             */
            PREPARE_DELAYED_WORK(&lu->work, sbp2_login);
      } else {
            lu->sdev = sdev;
            scsi_device_put(sdev);
      }
      kref_put(&lu->tgt->kref, sbp2_release_target);
}

static int sbp2_add_logical_unit(struct sbp2_target *tgt, int lun_entry)
{
      struct sbp2_logical_unit *lu;

      lu = kmalloc(sizeof(*lu), GFP_KERNEL);
      if (!lu)
            return -ENOMEM;

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

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

      lu->tgt  = tgt;
      lu->sdev = NULL;
      lu->lun  = lun_entry & 0xffff;
      lu->retries = 0;
      INIT_LIST_HEAD(&lu->orb_list);
      INIT_DELAYED_WORK(&lu->work, sbp2_login);

      list_add_tail(&lu->link, &tgt->lu_list);
      return 0;
}

static int sbp2_scan_logical_unit_dir(struct sbp2_target *tgt, u32 *directory)
{
      struct fw_csr_iterator ci;
      int key, value;

      fw_csr_iterator_init(&ci, directory);
      while (fw_csr_iterator_next(&ci, &key, &value))
            if (key == SBP2_CSR_LOGICAL_UNIT_NUMBER &&
                sbp2_add_logical_unit(tgt, value) < 0)
                  return -ENOMEM;
      return 0;
}

static int sbp2_scan_unit_dir(struct sbp2_target *tgt, u32 *directory,
                        u32 *model, u32 *firmware_revision)
{
      struct fw_csr_iterator ci;
      int key, value;

      fw_csr_iterator_init(&ci, directory);
      while (fw_csr_iterator_next(&ci, &key, &value)) {
            switch (key) {

            case CSR_DEPENDENT_INFO | CSR_OFFSET:
                  tgt->management_agent_address =
                              CSR_REGISTER_BASE + 4 * value;
                  break;

            case CSR_DIRECTORY_ID:
                  tgt->directory_id = value;
                  break;

            case CSR_MODEL:
                  *model = value;
                  break;

            case SBP2_CSR_FIRMWARE_REVISION:
                  *firmware_revision = value;
                  break;

            case SBP2_CSR_LOGICAL_UNIT_NUMBER:
                  if (sbp2_add_logical_unit(tgt, value) < 0)
                        return -ENOMEM;
                  break;

            case SBP2_CSR_LOGICAL_UNIT_DIRECTORY:
                  if (sbp2_scan_logical_unit_dir(tgt, ci.p + value) < 0)
                        return -ENOMEM;
                  break;
            }
      }
      return 0;
}

static void sbp2_init_workarounds(struct sbp2_target *tgt, u32 model,
                          u32 firmware_revision)
{
      int i;
      unsigned w = sbp2_param_workarounds;

      if (w)
            fw_notify("Please notify linux1394-devel@lists.sourceforge.net "
                    "if you need the workarounds parameter for %s\n",
                    tgt->unit->device.bus_id);

      if (w & SBP2_WORKAROUND_OVERRIDE)
            goto out;

      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;

            w |= sbp2_workarounds_table[i].workarounds;
            break;
      }
 out:
      if (w)
            fw_notify("Workarounds for %s: 0x%x "
                    "(firmware_revision 0x%06x, model_id 0x%06x)\n",
                    tgt->unit->device.bus_id,
                    w, firmware_revision, model);
      tgt->workarounds = w;
}

static struct scsi_host_template scsi_driver_template;

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_target *tgt;
      struct sbp2_logical_unit *lu;
      struct Scsi_Host *shost;
      u32 model, firmware_revision;

      shost = scsi_host_alloc(&scsi_driver_template, sizeof(*tgt));
      if (shost == NULL)
            return -ENOMEM;

      tgt = (struct sbp2_target *)shost->hostdata;
      unit->device.driver_data = tgt;
      tgt->unit = unit;
      kref_init(&tgt->kref);
      INIT_LIST_HEAD(&tgt->lu_list);

      if (fw_device_enable_phys_dma(device) < 0)
            goto fail_shost_put;

      if (scsi_add_host(shost, &unit->device) < 0)
            goto fail_shost_put;

      /* Initialize to values that won't match anything in our table. */
      firmware_revision = 0xff000000;
      model = 0xff000000;

      /* implicit directory ID */
      tgt->directory_id = ((unit->directory - device->config_rom) * 4
                       + CSR_CONFIG_ROM) & 0xffffff;

      if (sbp2_scan_unit_dir(tgt, unit->directory, &model,
                         &firmware_revision) < 0)
            goto fail_tgt_put;

      sbp2_init_workarounds(tgt, model, firmware_revision);

      get_device(&unit->device);

      /*
       * We schedule work to do the login so we can easily
       * reschedule retries. Always get the ref before scheduling
       * work.
       */
      list_for_each_entry(lu, &tgt->lu_list, link)
            if (queue_delayed_work(sbp2_wq, &lu->work, 0))
                  kref_get(&tgt->kref);
      return 0;

 fail_tgt_put:
      kref_put(&tgt->kref, sbp2_release_target);
      return -ENOMEM;

 fail_shost_put:
      scsi_host_put(shost);
      return -ENOMEM;
}

static int sbp2_remove(struct device *dev)
{
      struct fw_unit *unit = fw_unit(dev);
      struct sbp2_target *tgt = unit->device.driver_data;

      kref_put(&tgt->kref, sbp2_release_target);
      return 0;
}

static void sbp2_reconnect(struct work_struct *work)
{
      struct sbp2_logical_unit *lu =
            container_of(work, struct sbp2_logical_unit, work.work);
      struct fw_unit *unit = lu->tgt->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(lu, node_id, generation,
                             SBP2_RECONNECT_REQUEST,
                             lu->login_id, NULL) < 0) {
            if (lu->retries++ >= 5) {
                  fw_error("failed to reconnect to %s\n",
                         unit->device.bus_id);
                  /* Fall back and try to log in again. */
                  lu->retries = 0;
                  PREPARE_DELAYED_WORK(&lu->work, sbp2_login);
            }
            if (queue_delayed_work(sbp2_wq, &lu->work, DIV_ROUND_UP(HZ, 5)))
                  kref_get(&lu->tgt->kref);
            kref_put(&lu->tgt->kref, sbp2_release_target);
            return;
      }

      lu->generation        = generation;
      lu->tgt->node_id      = node_id;
      lu->tgt->address_high = local_node_id << 16;

      fw_notify("reconnected to %s LUN %04x (%d retries)\n",
              unit->device.bus_id, lu->lun, lu->retries);

      sbp2_agent_reset(lu);
      sbp2_cancel_orbs(lu);

      kref_put(&lu->tgt->kref, sbp2_release_target);
}

static void sbp2_update(struct fw_unit *unit)
{
      struct sbp2_target *tgt = unit->device.driver_data;
      struct sbp2_logical_unit *lu;

      fw_device_enable_phys_dma(fw_device(unit->device.parent));

      /*
       * Fw-core serializes sbp2_update() against sbp2_remove().
       * Iteration over tgt->lu_list is therefore safe here.
       */
      list_for_each_entry(lu, &tgt->lu_list, link) {
            lu->retries = 0;
            if (queue_delayed_work(sbp2_wq, &lu->work, 0))
                  kref_get(&tgt->kref);
      }
}

#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)
{
      int sam_status;

      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];

      sam_status = sbp2_status[0] & 0x3f;

      switch (sam_status) {
      case SAM_STAT_GOOD:
      case SAM_STAT_CHECK_CONDITION:
      case SAM_STAT_CONDITION_MET:
      case SAM_STAT_BUSY:
      case SAM_STAT_RESERVATION_CONFLICT:
      case SAM_STAT_COMMAND_TERMINATED:
            return DID_OK << 16 | sam_status;

      default:
            return DID_ERROR << 16;
      }
}

static void
complete_command_orb(struct sbp2_orb *base_orb, struct sbp2_status *status)
{
      struct sbp2_command_orb *orb =
            container_of(base_orb, struct sbp2_command_orb, base);
      struct fw_device *device = fw_device(orb->lu->tgt->unit->device.parent);
      int result;

      if (status != NULL) {
            if (STATUS_GET_DEAD(*status))
                  sbp2_agent_reset(orb->lu);

            switch (STATUS_GET_RESPONSE(*status)) {
            case SBP2_STATUS_REQUEST_COMPLETE:
                  result = DID_OK << 16;
                  break;
            case SBP2_STATUS_TRANSPORT_FAILURE:
                  result = DID_BUS_BUSY << 16;
                  break;
            case SBP2_STATUS_ILLEGAL_REQUEST:
            case SBP2_STATUS_VENDOR_DEPENDENT:
            default:
                  result = DID_ERROR << 16;
                  break;
            }

            if (result == DID_OK << 16 && 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).
             */
            result = DID_BUS_BUSY << 16;
      }

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

      if (scsi_sg_count(orb->cmd) > 0)
            dma_unmap_sg(device->card->device, scsi_sglist(orb->cmd),
                       scsi_sg_count(orb->cmd),
                       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), DMA_TO_DEVICE);

      orb->cmd->result = result;
      orb->done(orb->cmd);
}

static int
sbp2_map_scatterlist(struct sbp2_command_orb *orb, struct fw_device *device,
                 struct sbp2_logical_unit *lu)
{
      struct scatterlist *sg;
      int sg_len, l, i, j, count;
      dma_addr_t sg_addr;

      sg = scsi_sglist(orb->cmd);
      count = dma_map_sg(device->card->device, sg, scsi_sg_count(orb->cmd),
                     orb->cmd->sc_data_direction);
      if (count == 0)
            goto fail;

      /*
       * 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 = lu->tgt->address_high;
            orb->request.data_descriptor.low  = sg_dma_address(sg);
            orb->request.misc |= COMMAND_ORB_DATA_SIZE(sg_dma_len(sg));
            return 0;
      }

      /*
       * Convert the scatterlist to an sbp2 page table.  If any
       * scatterlist entries are too big for sbp2, we split them as we
       * go.  Even if we ask the block I/O layer to not give us sg
       * elements larger than 65535 bytes, some IOMMUs may merge sg elements
       * during DMA mapping, and Linux currently doesn't prevent this.
       */
      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) {
                  /* FIXME: This won't get us out of the pinch. */
                  if (unlikely(j >= ARRAY_SIZE(orb->page_table))) {
                        fw_error("page table overflow\n");
                        goto fail_page_table;
                  }
                  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++;
            }
      }

      fw_memcpy_to_be32(orb->page_table, orb->page_table,
                    sizeof(orb->page_table[0]) * j);
      orb->page_table_bus =
            dma_map_single(device->card->device, orb->page_table,
                         sizeof(orb->page_table), DMA_TO_DEVICE);
      if (dma_mapping_error(orb->page_table_bus))
            goto fail_page_table;

      /*
       * 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->request.data_descriptor.high = lu->tgt->address_high;
      orb->request.data_descriptor.low  = orb->page_table_bus;
      orb->request.misc |=
            COMMAND_ORB_PAGE_TABLE_PRESENT |
            COMMAND_ORB_DATA_SIZE(j);

      return 0;

 fail_page_table:
      dma_unmap_sg(device->card->device, sg, scsi_sg_count(orb->cmd),
                 orb->cmd->sc_data_direction);
 fail:
      return -ENOMEM;
}

/* SCSI stack integration */

static int sbp2_scsi_queuecommand(struct scsi_cmnd *cmd, scsi_done_fn_t done)
{
      struct sbp2_logical_unit *lu = cmd->device->hostdata;
      struct fw_device *device = fw_device(lu->tgt->unit->device.parent);
      struct sbp2_command_orb *orb;
      unsigned max_payload;
      int retval = SCSI_MLQUEUE_HOST_BUSY;

      /*
       * Bidirectional commands are not yet implemented, and unknown
       * transfer direction not handled.
       */
      if (cmd->sc_data_direction == DMA_BIDIRECTIONAL) {
            fw_error("Can't handle DMA_BIDIRECTIONAL, rejecting command\n");
            cmd->result = DID_ERROR << 16;
            done(cmd);
            return 0;
      }

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

      /* Initialize rcode to something not RCODE_COMPLETE. */
      orb->base.rcode = -1;
      kref_init(&orb->base.kref);

      orb->lu   = lu;
      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.
       */
      max_payload = min(device->max_speed + 7,
                    device->card->max_receive - 1);
      orb->request.misc =
            COMMAND_ORB_MAX_PAYLOAD(max_payload) |
            COMMAND_ORB_SPEED(device->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 (scsi_sg_count(cmd) && sbp2_map_scatterlist(orb, device, lu) < 0)
            goto out;

      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;
      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;

      sbp2_send_orb(&orb->base, lu, lu->tgt->node_id, lu->generation,
                  lu->command_block_agent_address + SBP2_ORB_POINTER);
      retval = 0;
 out:
      kref_put(&orb->base.kref, free_orb);
      return retval;
}

static int sbp2_scsi_slave_alloc(struct scsi_device *sdev)
{
      struct sbp2_logical_unit *lu = sdev->hostdata;

      sdev->allow_restart = 1;

      if (lu->tgt->workarounds & SBP2_WORKAROUND_INQUIRY_36)
            sdev->inquiry_len = 36;

      return 0;
}

static int sbp2_scsi_slave_configure(struct scsi_device *sdev)
{
      struct sbp2_logical_unit *lu = sdev->hostdata;

      sdev->use_10_for_rw = 1;

      if (sdev->type == TYPE_ROM)
            sdev->use_10_for_ms = 1;

      if (sdev->type == TYPE_DISK &&
          lu->tgt->workarounds & SBP2_WORKAROUND_MODE_SENSE_8)
            sdev->skip_ms_page_8 = 1;

      if (lu->tgt->workarounds & SBP2_WORKAROUND_FIX_CAPACITY)
            sdev->fix_capacity = 1;

      if (lu->tgt->workarounds & SBP2_WORKAROUND_128K_MAX_TRANS)
            blk_queue_max_sectors(sdev->request_queue, 128 * 1024 / 512);

      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 sbp2_logical_unit *lu = cmd->device->hostdata;

      fw_notify("sbp2_scsi_abort\n");
      sbp2_agent_reset(lu);
      sbp2_cancel_orbs(lu);

      return SUCCESS;
}

/*
 * Format of /sys/bus/scsi/devices/.../ieee1394_id:
 * u64 EUI-64 : u24 directory_ID : u16 LUN  (all printed in hexadecimal)
 *
 * This is the concatenation of target port identifier and logical unit
 * identifier as per SAM-2...SAM-4 annex A.
 */
static ssize_t
sbp2_sysfs_ieee1394_id_show(struct device *dev, struct device_attribute *attr,
                      char *buf)
{
      struct scsi_device *sdev = to_scsi_device(dev);
      struct sbp2_logical_unit *lu;
      struct fw_device *device;

      if (!sdev)
            return 0;

      lu = sdev->hostdata;
      device = fw_device(lu->tgt->unit->device.parent);

      return sprintf(buf, "%08x%08x:%06x:%04x\n",
                  device->config_rom[3], device->config_rom[4],
                  lu->tgt->directory_id, lu->lun);
}

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

static struct device_attribute *sbp2_scsi_sysfs_attrs[] = {
      &dev_attr_ieee1394_id,
      NULL
};

static struct scsi_host_template scsi_driver_template = {
      .module                 = THIS_MODULE,
      .name             = "SBP-2 IEEE-1394",
      .proc_name        = 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,
      .sdev_attrs       = sbp2_scsi_sysfs_attrs,
};

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

/* Provide a module alias so root-on-sbp2 initrds don't break. */
#ifndef CONFIG_IEEE1394_SBP2_MODULE
MODULE_ALIAS("sbp2");
#endif

static int __init sbp2_init(void)
{
      sbp2_wq = create_singlethread_workqueue(KBUILD_MODNAME);
      if (!sbp2_wq)
            return -ENOMEM;

      return driver_register(&sbp2_driver.driver);
}

static void __exit sbp2_cleanup(void)
{
      driver_unregister(&sbp2_driver.driver);
      destroy_workqueue(sbp2_wq);
}

module_init(sbp2_init);
module_exit(sbp2_cleanup);

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