text: /*
   * 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/blkdev.h>
  #include <linux/bug.h>
  #include <linux/completion.h>
  #include <linux/delay.h>
  #include <linux/device.h>
  #include <linux/dma-mapping.h>
  #include <linux/firewire.h>
  #include <linux/firewire-constants.h>
  #include <linux/init.h>
  #include <linux/jiffies.h>
  #include <linux/kernel.h>
  #include <linux/kref.h>
  #include <linux/list.h>
  #include <linux/mod_devicetable.h>
  #include <linux/module.h>
  #include <linux/moduleparam.h>
  #include <linux/scatterlist.h>
  #include <linux/slab.h>
  #include <linux/spinlock.h>
  #include <linux/string.h>
  #include <linux/stringify.h>
  #include <linux/workqueue.h>
  
  #include <asm/byteorder.h>
  
  #include <scsi/scsi.h>
  #include <scsi/scsi_cmnd.h>
  #include <scsi/scsi_device.h>
  #include <scsi/scsi_host.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 bool 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.
   *
   * - 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.
   */
  #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_DELAY_INQUIRY	0x10
  #define SBP2_INQUIRY_DELAY		12
  #define SBP2_WORKAROUND_POWER_CONDITION	0x20
  #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)
  	", 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)");
  
  /*
   * 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 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;
  	bool has_sdev;
  	bool blocked;
  };
  
  static void sbp2_queue_work(struct sbp2_logical_unit *lu, unsigned long delay)
  {
  	queue_delayed_work(fw_workqueue, &lu->work, delay);
  }
  
  /*
   * We create one struct sbp2_target per IEEE 1212 Unit Directory
   * and one struct Scsi_Host per sbp2_target.
   */
  struct sbp2_target {
  	struct fw_unit *unit;
  	struct list_head lu_list;
  
  	u64 management_agent_address;
  	u64 guid;
  	int directory_id;
  	int node_id;
  	int address_high;
  	unsigned int workarounds;
  	unsigned int mgt_orb_timeout;
  	unsigned int max_payload;
  
  	int dont_block;	/* counter for each logical unit */
  	int blocked;	/* ditto */
  };
  
  static struct fw_device *target_parent_device(struct sbp2_target *tgt)
  {
  	return fw_parent_device(tgt->unit);
  }
  
  static const struct device *tgt_dev(const struct sbp2_target *tgt)
  {
  	return &tgt->unit->device;
  }
  
  static const struct device *lu_dev(const struct sbp2_logical_unit *lu)
  {
  	return &lu->tgt->unit->device;
  }
  
  /* Impossible login_id, to detect logout attempt before successful login */
  #define INVALID_LOGIN_ID 0x10000
  
  #define SBP2_ORB_TIMEOUT		2000U		/* Timeout in ms */
  #define SBP2_ORB_NULL			0x80000000
  #define SBP2_RETRY_LIMIT		0xf		/* 15 retries */
  #define SBP2_CYCLE_LIMIT		(0xc8 << 12)	/* 200 125us cycles */
  
  /*
   * There is no transport protocol limit to the CDB length,  but we implement
   * a fixed length only.  16 bytes is enough for disks larger than 2 TB.
   */
  #define SBP2_MAX_CDB_SIZE		16
  
  /*
   * The default maximum s/g segment size of a FireWire controller is
   * usually 0x10000, but SBP-2 only allows 0xffff. Since buffers have to
   * be quadlet-aligned, we set the length limit to 0xffff & ~3.
   */
  #define SBP2_MAX_SEG_SIZE		0xfffc
  
  /* Unit directory keys */
  #define SBP2_CSR_UNIT_CHARACTERISTICS	0x3a
  #define SBP2_CSR_FIRMWARE_REVISION	0x3c
  #define SBP2_CSR_LOGICAL_UNIT_NUMBER	0x14
  #define SBP2_CSR_UNIT_UNIQUE_ID		0x8d
  #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 {
  	__be32 high;
  	__be32 low;
  };
  
  struct sbp2_orb {
  	struct fw_transaction t;
  	struct kref kref;
  	dma_addr_t request_bus;
  	int rcode;
  	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;
  		__be32 misc;
  		__be32 length;
  		struct sbp2_pointer status_fifo;
  	} request;
  	__be32 response[4];
  	dma_addr_t response_bus;
  	struct completion done;
  	struct sbp2_status status;
  };
  
  struct sbp2_login_response {
  	__be32 misc;
  	struct sbp2_pointer command_block_agent;
  	__be32 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		((1) << 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;
  		__be32 misc;
  		u8 command_block[SBP2_MAX_CDB_SIZE];
  	} request;
  	struct scsi_cmnd *cmd;
  	struct sbp2_logical_unit *lu;
  
  	struct sbp2_pointer page_table[SG_ALL] __attribute__((aligned(8)));
  	dma_addr_t page_table_bus;
  };
  
  #define SBP2_ROM_VALUE_WILDCARD ~0         /* match all */
  #define SBP2_ROM_VALUE_MISSING  0xff000000 /* not present in the unit dir. */
  
  /*
   * 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;
  	unsigned int 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 |
  					  SBP2_WORKAROUND_POWER_CONDITION,
  	},
  	/* DViCO Momobay FX-3A with TSB42AA9A bridge */ {
  		.firmware_revision	= 0x002800,
  		.model			= 0x000000,
  		.workarounds		= SBP2_WORKAROUND_POWER_CONDITION,
  	},
  	/* Initio bridges, actually only needed for some older ones */ {
  		.firmware_revision	= 0x000200,
  		.model			= SBP2_ROM_VALUE_WILDCARD,
  		.workarounds		= SBP2_WORKAROUND_INQUIRY_36,
  	},
  	/* PL-3507 bridge with Prolific firmware */ {
  		.firmware_revision	= 0x012800,
  		.model			= SBP2_ROM_VALUE_WILDCARD,
  		.workarounds		= SBP2_WORKAROUND_POWER_CONDITION,
  	},
  	/* Symbios bridge */ {
  		.firmware_revision	= 0xa0b800,
  		.model			= SBP2_ROM_VALUE_WILDCARD,
  		.workarounds		= SBP2_WORKAROUND_128K_MAX_TRANS,
  	},
  	/* Datafab MD2-FW2 with Symbios/LSILogic SYM13FW500 bridge */ {
  		.firmware_revision	= 0x002600,
  		.model			= SBP2_ROM_VALUE_WILDCARD,
  		.workarounds		= SBP2_WORKAROUND_128K_MAX_TRANS,
  	},
  	/*
  	 * iPod 2nd generation: needs 128k max transfer size workaround
  	 * iPod 3rd generation: needs fix capacity workaround
  	 */
  	{
  		.firmware_revision	= 0x0a2700,
  		.model			= 0x000000,
  		.workarounds		= SBP2_WORKAROUND_128K_MAX_TRANS |
  					  SBP2_WORKAROUND_FIX_CAPACITY,
  	},
  	/* iPod 4th generation */ {
  		.firmware_revision	= 0x0a2700,
  		.model			= 0x000021,
  		.workarounds		= SBP2_WORKAROUND_FIX_CAPACITY,
  	},
  	/* iPod mini */ {
  		.firmware_revision	= 0x0a2700,
  		.model			= 0x000022,
  		.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, 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;
  	unsigned long flags;
  
  	if (tcode != TCODE_WRITE_BLOCK_REQUEST ||
  	    length < 8 || length > sizeof(status)) {
  		fw_send_response(card, request, RCODE_TYPE_ERROR);
  		return;
  	}
  
  	status.status  = be32_to_cpup(payload);
  	status.orb_low = be32_to_cpup(payload + 4);
  	memset(status.data, 0, sizeof(status.data));
  	if (length > 8)
  		memcpy(status.data, payload + 8, length - 8);
  
  	if (STATUS_GET_SOURCE(status) == 2 || STATUS_GET_SOURCE(status) == 3) {
  		dev_notice(lu_dev(lu),
  			   "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);
  		kref_put(&orb->kref, free_orb); /* orb callback reference */
  	} else {
  		dev_err(lu_dev(lu), "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;
  
  	/*
  	 * 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);
  		kref_put(&orb->kref, free_orb); /* orb callback reference */
  	} else {
  		spin_unlock_irqrestore(&card->lock, flags);
  	}
  
  	kref_put(&orb->kref, free_orb); /* transaction callback reference */
  }
  
  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 = target_parent_device(lu->tgt);
  	struct sbp2_pointer orb_pointer;
  	unsigned long flags;
  
  	orb_pointer.high = 0;
  	orb_pointer.low = cpu_to_be32(orb->request_bus);
  
  	spin_lock_irqsave(&device->card->lock, flags);
  	list_add_tail(&orb->link, &lu->orb_list);
  	spin_unlock_irqrestore(&device->card->lock, flags);
  
  	kref_get(&orb->kref); /* transaction callback reference */
  	kref_get(&orb->kref); /* orb callback reference */
  
  	fw_send_request(device->card, &orb->t, TCODE_WRITE_BLOCK_REQUEST,
  			node_id, generation, device->max_speed, offset,
  			&orb_pointer, 8, complete_transaction, orb);
  }
  
  static int sbp2_cancel_orbs(struct sbp2_logical_unit *lu)
  {
  	struct fw_device *device = target_parent_device(lu->tgt);
  	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);
  		kref_put(&orb->kref, free_orb); /* orb callback reference */
  	}
  
  	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 = target_parent_device(lu->tgt);
  	struct sbp2_management_orb *orb;
  	unsigned int timeout;
  	int retval = -ENOMEM;
  
  	if (function == SBP2_LOGOUT_REQUEST && fw_device_is_shutdown(device))
  		return 0;
  
  	orb = kzalloc(sizeof(*orb), GFP_NOIO);
  	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(device->card->device, orb->response_bus))
  		goto fail_mapping_response;
  
  	orb->request.response.high = 0;
  	orb->request.response.low  = cpu_to_be32(orb->response_bus);
  
  	orb->request.misc = cpu_to_be32(
  		MANAGEMENT_ORB_NOTIFY |
  		MANAGEMENT_ORB_FUNCTION(function) |
  		MANAGEMENT_ORB_LUN(lun_or_login_id));
  	orb->request.length = cpu_to_be32(
  		MANAGEMENT_ORB_RESPONSE_LENGTH(sizeof(orb->response)));
  
  	orb->request.status_fifo.high =
  		cpu_to_be32(lu->address_handler.offset >> 32);
  	orb->request.status_fifo.low  =
  		cpu_to_be32(lu->address_handler.offset);
  
  	if (function == SBP2_LOGIN_REQUEST) {
  		/* Ask for 2^2 == 4 seconds reconnect grace period */
  		orb->request.misc |= cpu_to_be32(
  			MANAGEMENT_ORB_RECONNECT(2) |
  			MANAGEMENT_ORB_EXCLUSIVE(sbp2_param_exclusive_login));
  		timeout = lu->tgt->mgt_orb_timeout;
  	} else {
  		timeout = SBP2_ORB_TIMEOUT;
  	}
  
  	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(device->card->device, 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(timeout));
  
  	retval = -EIO;
  	if (sbp2_cancel_orbs(lu) == 0) {
  		dev_err(lu_dev(lu), "ORB reply timed out, rcode 0x%02x\n",
  			orb->base.rcode);
  		goto out;
  	}
  
  	if (orb->base.rcode != RCODE_COMPLETE) {
  		dev_err(lu_dev(lu), "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) {
  		dev_err(lu_dev(lu), "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)
  		memcpy(response, orb->response, sizeof(orb->response));
  	kref_put(&orb->base.kref, free_orb);
  
  	return retval;
  }
  
  static void sbp2_agent_reset(struct sbp2_logical_unit *lu)
  {
  	struct fw_device *device = target_parent_device(lu->tgt);
  	__be32 d = 0;
  
  	fw_run_transaction(device->card, TCODE_WRITE_QUADLET_REQUEST,
  			   lu->tgt->node_id, lu->generation, device->max_speed,
  			   lu->command_block_agent_address + SBP2_AGENT_RESET,
  			   &d, 4);
  }
  
  static void complete_agent_reset_write_no_wait(struct fw_card *card,
  		int rcode, void *payload, size_t length, void *data)
  {
  	kfree(data);
  }
  
  static void sbp2_agent_reset_no_wait(struct sbp2_logical_unit *lu)
  {
  	struct fw_device *device = target_parent_device(lu->tgt);
  	struct fw_transaction *t;
  	static __be32 d;
  
  	t = kmalloc(sizeof(*t), GFP_ATOMIC);
  	if (t == NULL)
  		return;
  
  	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,
  			&d, 4, complete_agent_reset_write_no_wait, t);
  }
  
  static inline void sbp2_allow_block(struct sbp2_logical_unit *lu)
  {
  	/*
  	 * We may access dont_block without taking card->lock here:
  	 * All callers of sbp2_allow_block() and all callers of sbp2_unblock()
  	 * are currently serialized against each other.
  	 * And a wrong result in sbp2_conditionally_block()'s access of
  	 * dont_block is rather harmless, it simply misses its first chance.
  	 */
  	--lu->tgt->dont_block;
  }
  
  /*
   * Blocks lu->tgt if all of the following conditions are met:
   *   - Login, INQUIRY, and high-level SCSI setup of all of the target's
   *     logical units have been finished (indicated by dont_block == 0).
   *   - lu->generation is stale.
   *
   * Note, scsi_block_requests() must be called while holding card->lock,
   * otherwise it might foil sbp2_[conditionally_]unblock()'s attempt to
   * unblock the target.
   */
  static void sbp2_conditionally_block(struct sbp2_logical_unit *lu)
  {
  	struct sbp2_target *tgt = lu->tgt;
  	struct fw_card *card = target_parent_device(tgt)->card;
  	struct Scsi_Host *shost =
  		container_of((void *)tgt, struct Scsi_Host, hostdata[0]);
  	unsigned long flags;
  
  	spin_lock_irqsave(&card->lock, flags);
  	if (!tgt->dont_block && !lu->blocked &&
  	    lu->generation != card->generation) {
  		lu->blocked = true;
  		if (++tgt->blocked == 1)
  			scsi_block_requests(shost);
  	}
  	spin_unlock_irqrestore(&card->lock, flags);
  }
  
  /*
   * Unblocks lu->tgt as soon as all its logical units can be unblocked.
   * Note, it is harmless to run scsi_unblock_requests() outside the
   * card->lock protected section.  On the other hand, running it inside
   * the section might clash with shost->host_lock.
   */
  static void sbp2_conditionally_unblock(struct sbp2_logical_unit *lu)
  {
  	struct sbp2_target *tgt = lu->tgt;
  	struct fw_card *card = target_parent_device(tgt)->card;
  	struct Scsi_Host *shost =
  		container_of((void *)tgt, struct Scsi_Host, hostdata[0]);
  	unsigned long flags;
  	bool unblock = false;
  
  	spin_lock_irqsave(&card->lock, flags);
  	if (lu->blocked && lu->generation == card->generation) {
  		lu->blocked = false;
  		unblock = --tgt->blocked == 0;
  	}
  	spin_unlock_irqrestore(&card->lock, flags);
  
  	if (unblock)
  		scsi_unblock_requests(shost);
  }
  
  /*
   * Prevents future blocking of tgt and unblocks it.
   * Note, it is harmless to run scsi_unblock_requests() outside the
   * card->lock protected section.  On the other hand, running it inside
   * the section might clash with shost->host_lock.
   */
  static void sbp2_unblock(struct sbp2_target *tgt)
  {
  	struct fw_card *card = target_parent_device(tgt)->card;
  	struct Scsi_Host *shost =
  		container_of((void *)tgt, struct Scsi_Host, hostdata[0]);
  	unsigned long flags;
  
  	spin_lock_irqsave(&card->lock, flags);
  	++tgt->dont_block;
  	spin_unlock_irqrestore(&card->lock, flags);
  
  	scsi_unblock_requests(shost);
  }
  
  static int sbp2_lun2int(u16 lun)
  {
  	struct scsi_lun eight_bytes_lun;
  
  	memset(&eight_bytes_lun, 0, sizeof(eight_bytes_lun));
  	eight_bytes_lun.scsi_lun[0] = (lun >> 8) & 0xff;
  	eight_bytes_lun.scsi_lun[1] = lun & 0xff;
  
  	return scsilun_to_int(&eight_bytes_lun);
  }
  
  /*
   * Write retransmit retry values into the BUSY_TIMEOUT register.
   * - The single-phase retry protocol is supported by all SBP-2 devices, but the
   *   default retry_limit value is 0 (i.e. never retry transmission). We write a
   *   saner value after logging into the device.
   * - The dual-phase retry protocol is optional to implement, and if not
   *   supported, writes to the dual-phase portion of the register will be
   *   ignored. We try to write the original 1394-1995 default here.
   * - In the case of devices that are also SBP-3-compliant, all writes are
   *   ignored, as the register is read-only, but contains single-phase retry of
   *   15, which is what we're trying to set for all SBP-2 device anyway, so this
   *   write attempt is safe and yields more consistent behavior for all devices.
   *
   * See section 8.3.2.3.5 of the 1394-1995 spec, section 6.2 of the SBP-2 spec,
   * and section 6.4 of the SBP-3 spec for further details.
   */
  static void sbp2_set_busy_timeout(struct sbp2_logical_unit *lu)
  {
  	struct fw_device *device = target_parent_device(lu->tgt);
  	__be32 d = cpu_to_be32(SBP2_CYCLE_LIMIT | SBP2_RETRY_LIMIT);
  
  	fw_run_transaction(device->card, TCODE_WRITE_QUADLET_REQUEST,
  			   lu->tgt->node_id, lu->generation, device->max_speed,
  			   CSR_REGISTER_BASE + CSR_BUSY_TIMEOUT, &d, 4);
  }
  
  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 sbp2_target *tgt = lu->tgt;
  	struct fw_device *device = target_parent_device(tgt);
  	struct Scsi_Host *shost;
  	struct scsi_device *sdev;
  	struct sbp2_login_response response;
  	int generation, node_id, local_node_id;
  
  	if (fw_device_is_shutdown(device))
  		return;
  
  	generation    = device->generation;
  	smp_rmb();    /* node IDs must not be older than generation */
  	node_id       = device->node_id;
  	local_node_id = device->card->node_id;
  
  	/* If this is a re-login attempt, log out, or we might be rejected. */
  	if (lu->has_sdev)
  		sbp2_send_management_orb(lu, device->node_id, generation,
  				SBP2_LOGOUT_REQUEST, lu->login_id, NULL);
  
  	if (sbp2_send_management_orb(lu, node_id, generation,
  				SBP2_LOGIN_REQUEST, lu->lun, &response) < 0) {
  		if (lu->retries++ < 5) {
  			sbp2_queue_work(lu, DIV_ROUND_UP(HZ, 5));
  		} else {
  			dev_err(tgt_dev(tgt), "failed to login to LUN %04x\n",
  				lu->lun);
  			/* Let any waiting I/O fail from now on. */
  			sbp2_unblock(lu->tgt);
  		}
  		return;
  	}
  
  	tgt->node_id	  = node_id;
  	tgt->address_high = local_node_id << 16;
  	smp_wmb();	  /* node IDs must not be older than generation */
  	lu->generation	  = generation;
  
  	lu->command_block_agent_address =
  		((u64)(be32_to_cpu(response.command_block_agent.high) & 0xffff)
  		      << 32) | be32_to_cpu(response.command_block_agent.low);
  	lu->login_id = be32_to_cpu(response.misc) & 0xffff;
  
  	dev_notice(tgt_dev(tgt), "logged in to LUN %04x (%d retries)\n",
  		   lu->lun, lu->retries);
  
  	/* set appropriate retry limit(s) in BUSY_TIMEOUT register */
  	sbp2_set_busy_timeout(lu);
  
  	PREPARE_DELAYED_WORK(&lu->work, sbp2_reconnect);
  	sbp2_agent_reset(lu);
  
  	/* This was a re-login. */
  	if (lu->has_sdev) {
  		sbp2_cancel_orbs(lu);
  		sbp2_conditionally_unblock(lu);
  
  		return;
  	}
  
  	if (lu->tgt->workarounds & SBP2_WORKAROUND_DELAY_INQUIRY)
  		ssleep(SBP2_INQUIRY_DELAY);
  
  	shost = container_of((void *)tgt, struct Scsi_Host, hostdata[0]);
  	sdev = __scsi_add_device(shost, 0, 0, sbp2_lun2int(lu->lun), lu);
  	/*
  	 * FIXME:  We are unable to perform reconnects while in sbp2_login().
  	 * Therefore __scsi_add_device() will get into trouble if a bus reset
  	 * happens in parallel.  It will either fail or leave us with an
  	 * unusable sdev.  As a workaround we check for this and retry the
  	 * whole login and SCSI probing.
  	 */
  
  	/* Reported error during __scsi_add_device() */
  	if (IS_ERR(sdev))
  		goto out_logout_login;
  
  	/* Unreported error during __scsi_add_device() */
  	smp_rmb(); /* get current card generation */
  	if (generation != device->card->generation) {
  		scsi_remove_device(sdev);
  		scsi_device_put(sdev);
  		goto out_logout_login;
  	}
  
  	/* No error during __scsi_add_device() */
  	lu->has_sdev = true;
  	scsi_device_put(sdev);
  	sbp2_allow_block(lu);
  
  	return;
  
   out_logout_login:
  	smp_rmb(); /* generation may have changed */
  	generation = device->generation;
  	smp_rmb(); /* node_id must not be older than generation */
  
  	sbp2_send_management_orb(lu, device->node_id, generation,
  				 SBP2_LOGOUT_REQUEST, lu->login_id, NULL);
  	/*
  	 * If a bus reset happened, sbp2_update will have requeued
  	 * lu->work already.  Reset the work from reconnect to login.
  	 */
  	PREPARE_DELAYED_WORK(&lu->work, sbp2_login);
  }
  
  static void sbp2_reconnect(struct work_struct *work)
  {
  	struct sbp2_logical_unit *lu =
  		container_of(work, struct sbp2_logical_unit, work.work);
  	struct sbp2_target *tgt = lu->tgt;
  	struct fw_device *device = target_parent_device(tgt);
  	int generation, node_id, local_node_id;
  
  	if (fw_device_is_shutdown(device))
  		return;
  
  	generation    = device->generation;
  	smp_rmb();    /* node IDs must not be older than generation */
  	node_id       = device->node_id;
  	local_node_id = device->card->node_id;
  
  	if (sbp2_send_management_orb(lu, node_id, generation,
  				     SBP2_RECONNECT_REQUEST,
  				     lu->login_id, NULL) < 0) {
  		/*
  		 * If reconnect was impossible even though we are in the
  		 * current generation, fall back and try to log in again.
  		 *
  		 * We could check for "Function rejected" status, but
  		 * looking at the bus generation as simpler and more general.
  		 */
  		smp_rmb(); /* get current card generation */
  		if (generation == device->card->generation ||
  		    lu->retries++ >= 5) {
  			dev_err(tgt_dev(tgt), "failed to reconnect\n");
  			lu->retries = 0;
  			PREPARE_DELAYED_WORK(&lu->work, sbp2_login);
  		}
  		sbp2_queue_work(lu, DIV_ROUND_UP(HZ, 5));
  
  		return;
  	}
  
  	tgt->node_id      = node_id;
  	tgt->address_high = local_node_id << 16;
  	smp_wmb();	  /* node IDs must not be older than generation */
  	lu->generation	  = generation;
  
  	dev_notice(tgt_dev(tgt), "reconnected to LUN %04x (%d retries)\n",
  		   lu->lun, lu->retries);
  
  	sbp2_agent_reset(lu);
  	sbp2_cancel_orbs(lu);
  	sbp2_conditionally_unblock(lu);
  }
  
  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->lun      = lun_entry & 0xffff;
  	lu->login_id = INVALID_LOGIN_ID;
  	lu->retries  = 0;
  	lu->has_sdev = false;
  	lu->blocked  = false;
  	++tgt->dont_block;
  	INIT_LIST_HEAD(&lu->orb_list);
  	INIT_DELAYED_WORK(&lu->work, sbp2_login);
  
  	list_add_tail(&lu->link, &tgt->lu_list);
  	return 0;
  }
  
  static void sbp2_get_unit_unique_id(struct sbp2_target *tgt,
  				    const u32 *leaf)
  {
  	if ((leaf[0] & 0xffff0000) == 0x00020000)
  		tgt->guid = (u64)leaf[1] << 32 | leaf[2];
  }
  
  static int sbp2_scan_logical_unit_dir(struct sbp2_target *tgt,
  				      const 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, const 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_UNIT_CHARACTERISTICS:
  			/* the timeout value is stored in 500ms units */
  			tgt->mgt_orb_timeout = (value >> 8 & 0xff) * 500;
  			break;
  
  		case SBP2_CSR_LOGICAL_UNIT_NUMBER:
  			if (sbp2_add_logical_unit(tgt, value) < 0)
  				return -ENOMEM;
  			break;
  
  		case SBP2_CSR_UNIT_UNIQUE_ID:
  			sbp2_get_unit_unique_id(tgt, ci.p - 1 + value);
  			break;
  
  		case SBP2_CSR_LOGICAL_UNIT_DIRECTORY:
  			/* Adjust for the increment in the iterator */
  			if (sbp2_scan_logical_unit_dir(tgt, ci.p - 1 + value) < 0)
  				return -ENOMEM;
  			break;
  		}
  	}
  	return 0;
  }
  
  /*
   * Per section 7.4.8 of the SBP-2 spec, a mgt_ORB_timeout value can be
   * provided in the config rom. Most devices do provide a value, which
   * we'll use for login management orbs, but with some sane limits.
   */
  static void sbp2_clamp_management_orb_timeout(struct sbp2_target *tgt)
  {
  	unsigned int timeout = tgt->mgt_orb_timeout;
  
  	if (timeout > 40000)
  		dev_notice(tgt_dev(tgt), "%ds mgt_ORB_timeout limited to 40s\n",
  			   timeout / 1000);
  
  	tgt->mgt_orb_timeout = clamp_val(timeout, 5000, 40000);
  }
  
  static void sbp2_init_workarounds(struct sbp2_target *tgt, u32 model,
  				  u32 firmware_revision)
  {
  	int i;
  	unsigned int w = sbp2_param_workarounds;
  
  	if (w)
  		dev_notice(tgt_dev(tgt),
  			   "Please notify linux1394-devel@lists.sf.net "
  			   "if you need the workarounds parameter\n");
  
  	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 != SBP2_ROM_VALUE_WILDCARD)
  			continue;
  
  		w |= sbp2_workarounds_table[i].workarounds;
  		break;
  	}
   out:
  	if (w)
  		dev_notice(tgt_dev(tgt), "workarounds 0x%x "
  			   "(firmware_revision 0x%06x, model_id 0x%06x)\n",
  			   w, firmware_revision, model);
  	tgt->workarounds = w;
  }
  
  static struct scsi_host_template scsi_driver_template;
  static int sbp2_remove(struct device *dev);
  
  static int sbp2_probe(struct device *dev)
  {
  	struct fw_unit *unit = fw_unit(dev);
  	struct fw_device *device = fw_parent_device(unit);
  	struct sbp2_target *tgt;
  	struct sbp2_logical_unit *lu;
  	struct Scsi_Host *shost;
  	u32 model, firmware_revision;
  
  	/* cannot (or should not) handle targets on the local node */
  	if (device->is_local)
  		return -ENODEV;
  
  	if (dma_get_max_seg_size(device->card->device) > SBP2_MAX_SEG_SIZE)
  		BUG_ON(dma_set_max_seg_size(device->card->device,
  					    SBP2_MAX_SEG_SIZE));
  
  	shost = scsi_host_alloc(&scsi_driver_template, sizeof(*tgt));
  	if (shost == NULL)
  		return -ENOMEM;
  
  	tgt = (struct sbp2_target *)shost->hostdata;
  	dev_set_drvdata(&unit->device, tgt);
  	tgt->unit = unit;
  	INIT_LIST_HEAD(&tgt->lu_list);
  	tgt->guid = (u64)device->config_rom[3] << 32 | device->config_rom[4];
  
  	if (fw_device_enable_phys_dma(device) < 0)
  		goto fail_shost_put;
  
  	shost->max_cmd_len = SBP2_MAX_CDB_SIZE;
  
  	if (scsi_add_host(shost, &unit->device) < 0)
  		goto fail_shost_put;
  
  	/* implicit directory ID */
  	tgt->directory_id = ((unit->directory - device->config_rom) * 4
  			     + CSR_CONFIG_ROM) & 0xffffff;
  
  	firmware_revision = SBP2_ROM_VALUE_MISSING;
  	model		  = SBP2_ROM_VALUE_MISSING;
  
  	if (sbp2_scan_unit_dir(tgt, unit->directory, &model,
  			       &firmware_revision) < 0)
  		goto fail_remove;
  
  	sbp2_clamp_management_orb_timeout(tgt);
  	sbp2_init_workarounds(tgt, model, firmware_revision);
  
  	/*
  	 * At S100 we can do 512 bytes per packet, at S200 1024 bytes,
  	 * and so on up to 4096 bytes.  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.
  	 */
  	tgt->max_payload = min3(device->max_speed + 7, 10U,
  				device->card->max_receive - 1);
  
  	/* Do the login in a workqueue so we can easily reschedule retries. */
  	list_for_each_entry(lu, &tgt->lu_list, link)
  		sbp2_queue_work(lu, DIV_ROUND_UP(HZ, 5));
  
  	return 0;
  
   fail_remove:
  	sbp2_remove(dev);
  	return -ENOMEM;
  
   fail_shost_put:
  	scsi_host_put(shost);
  	return -ENOMEM;
  }
  
  static void sbp2_update(struct fw_unit *unit)
  {
  	struct sbp2_target *tgt = dev_get_drvdata(&unit->device);
  	struct sbp2_logical_unit *lu;
  
  	fw_device_enable_phys_dma(fw_parent_device(unit));
  
  	/*
  	 * 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) {
  		sbp2_conditionally_block(lu);
  		lu->retries = 0;
  		sbp2_queue_work(lu, 0);
  	}
  }
  
  static int sbp2_remove(struct device *dev)
  {
  	struct fw_unit *unit = fw_unit(dev);
  	struct fw_device *device = fw_parent_device(unit);
  	struct sbp2_target *tgt = dev_get_drvdata(&unit->device);
  	struct sbp2_logical_unit *lu, *next;
  	struct Scsi_Host *shost =
  		container_of((void *)tgt, struct Scsi_Host, hostdata[0]);
  	struct scsi_device *sdev;
  
  	/* prevent deadlocks */
  	sbp2_unblock(tgt);
  
  	list_for_each_entry_safe(lu, next, &tgt->lu_list, link) {
  		cancel_delayed_work_sync(&lu->work);
  		sdev = scsi_device_lookup(shost, 0, 0, sbp2_lun2int(lu->lun));
  		if (sdev) {
  			scsi_remove_device(sdev);
  			scsi_device_put(sdev);
  		}
  		if (lu->login_id != INVALID_LOGIN_ID) {
  			int generation, node_id;
  			/*
  			 * tgt->node_id may be obsolete here if we failed
  			 * during initial login or after a bus reset where
  			 * the topology changed.
  			 */
  			generation = device->generation;
  			smp_rmb(); /* node_id vs. generation */
  			node_id    = device->node_id;
  			sbp2_send_management_orb(lu, node_id, 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);
  	dev_notice(dev, "released target %d:0:0\n", shost->host_no);
  
  	scsi_host_put(shost);
  	return 0;
  }
  
  #define SBP2_UNIT_SPEC_ID_ENTRY	0x0000609e
  #define SBP2_SW_VERSION_ENTRY	0x00010483
  
  static const struct ieee1394_device_id sbp2_id_table[] = {
  	{
  		.match_flags  = IEEE1394_MATCH_SPECIFIER_ID |
  				IEEE1394_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   = KBUILD_MODNAME,
  		.bus    = &fw_bus_type,
  		.probe  = sbp2_probe,
  		.remove = sbp2_remove,
  	},
  	.update   = sbp2_update,
  	.id_table = sbp2_id_table,
  };
  
  static void sbp2_unmap_scatterlist(struct device *card_device,
  				   struct sbp2_command_orb *orb)
  {
  	if (scsi_sg_count(orb->cmd))
  		dma_unmap_sg(card_device, scsi_sglist(orb->cmd),
  			     scsi_sg_count(orb->cmd),
  			     orb->cmd->sc_data_direction);
  
  	if (orb->request.misc & cpu_to_be32(COMMAND_ORB_PAGE_TABLE_PRESENT))
  		dma_unmap_single(card_device, orb->page_table_bus,
  				 sizeof(orb->page_table), DMA_TO_DEVICE);
  }
  
  static unsigned int sbp2_status_to_sense_data(u8 *sbp2_status, u8 *sense_data)
  {
  	int sam_status;
  	int sfmt = (sbp2_status[0] >> 6) & 0x03;
  
  	if (sfmt == 2 || sfmt == 3) {
  		/*
  		 * Reserved for future standardization (2) or
  		 * Status block format vendor-dependent (3)
  		 */
  		return DID_ERROR << 16;
  	}
  
  	sense_data[0] = 0x70 | sfmt | (sbp2_status[1] & 0x80);
  	sense_data[1] = 0x0;
  	sense_data[2] = ((sbp2_status[1] << 1) & 0xe0) | (sbp2_status[1] & 0x0f);
  	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 = target_parent_device(orb->lu->tgt);
  	int result;
  
  	if (status != NULL) {
  		if (STATUS_GET_DEAD(*status))
  			sbp2_agent_reset_no_wait(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;
  		sbp2_conditionally_block(orb->lu);
  	}
  
  	dma_unmap_single(device->card->device, orb->base.request_bus,
  			 sizeof(orb->request), DMA_TO_DEVICE);
  	sbp2_unmap_scatterlist(device->card->device, orb);
  
  	orb->cmd->result = result;
  	orb->cmd->scsi_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 = scsi_sglist(orb->cmd);
  	int i, n;
  
  	n = dma_map_sg(device->card->device, sg, scsi_sg_count(orb->cmd),
  		       orb->cmd->sc_data_direction);
  	if (n == 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 (n == 1) {
  		orb->request.data_descriptor.high =
  			cpu_to_be32(lu->tgt->address_high);
  		orb->request.data_descriptor.low  =
  			cpu_to_be32(sg_dma_address(sg));
  		orb->request.misc |=
  			cpu_to_be32(COMMAND_ORB_DATA_SIZE(sg_dma_len(sg)));
  		return 0;
  	}
  
  	for_each_sg(sg, sg, n, i) {
  		orb->page_table[i].high = cpu_to_be32(sg_dma_len(sg) << 16);
  		orb->page_table[i].low = cpu_to_be32(sg_dma_address(sg));
  	}
  
  	orb->page_table_bus =
  		dma_map_single(device->card->device, orb->page_table,
  			       sizeof(orb->page_table), DMA_TO_DEVICE);
  	if (dma_mapping_error(device->card->device, 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 = cpu_to_be32(lu->tgt->address_high);
  	orb->request.data_descriptor.low  = cpu_to_be32(orb->page_table_bus);
  	orb->request.misc |= cpu_to_be32(COMMAND_ORB_PAGE_TABLE_PRESENT |
  					 COMMAND_ORB_DATA_SIZE(n));
  
  	return 0;
  
   fail_page_table:
  	dma_unmap_sg(device->card->device, scsi_sglist(orb->cmd),
  		     scsi_sg_count(orb->cmd), orb->cmd->sc_data_direction);
   fail:
  	return -ENOMEM;
  }
  
  /* SCSI stack integration */
  
  static int sbp2_scsi_queuecommand(struct Scsi_Host *shost,
  				  struct scsi_cmnd *cmd)
  {
  	struct sbp2_logical_unit *lu = cmd->device->hostdata;
  	struct fw_device *device = target_parent_device(lu->tgt);
  	struct sbp2_command_orb *orb;
  	int generation, retval = SCSI_MLQUEUE_HOST_BUSY;
  
  	/*
  	 * Bidirectional commands are not yet implemented, and unknown
  	 * transfer direction not handled.
  	 */
  	if (cmd->sc_data_direction == DMA_BIDIRECTIONAL) {
  		dev_err(lu_dev(lu), "cannot handle bidirectional command\n");
  		cmd->result = DID_ERROR << 16;
  		cmd->scsi_done(cmd);
  		return 0;
  	}
  
  	orb = kzalloc(sizeof(*orb), GFP_ATOMIC);
  	if (orb == NULL) {
  		dev_notice(lu_dev(lu), "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->cmd = cmd;
  	orb->request.next.high = cpu_to_be32(SBP2_ORB_NULL);
  	orb->request.misc = cpu_to_be32(
  		COMMAND_ORB_MAX_PAYLOAD(lu->tgt->max_payload) |
  		COMMAND_ORB_SPEED(device->max_speed) |
  		COMMAND_ORB_NOTIFY);
  
  	if (cmd->sc_data_direction == DMA_FROM_DEVICE)
  		orb->request.misc |= cpu_to_be32(COMMAND_ORB_DIRECTION);
  
  	generation = device->generation;
  	smp_rmb();    /* sbp2_map_scatterlist looks at tgt->address_high */
  
  	if (scsi_sg_count(cmd) && sbp2_map_scatterlist(orb, device, lu) < 0)
  		goto out;
  
  	memcpy(orb->request.command_block, cmd->cmnd, cmd->cmd_len);
  
  	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(device->card->device, orb->base.request_bus)) {
  		sbp2_unmap_scatterlist(device->card->device, orb);
  		goto out;
  	}
  
  	sbp2_send_orb(&orb->base, lu, lu->tgt->node_id, 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;
  
  	/* (Re-)Adding logical units via the SCSI stack is not supported. */
  	if (!lu)
  		return -ENOSYS;
  
  	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->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 (sbp2_param_exclusive_login)
  		sdev->manage_start_stop = 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_POWER_CONDITION)
  		sdev->start_stop_pwr_cond = 1;
  
  	if (lu->tgt->workarounds & SBP2_WORKAROUND_128K_MAX_TRANS)
  		blk_queue_max_hw_sectors(sdev->request_queue, 128 * 1024 / 512);
  
  	blk_queue_max_segment_size(sdev->request_queue, SBP2_MAX_SEG_SIZE);
  
  	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;
  
  	dev_notice(lu_dev(lu), "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;
  
  	if (!sdev)
  		return 0;
  
  	lu = sdev->hostdata;
  
  	return sprintf(buf, "%016llx:%06x:%04x\n",
  			(unsigned long long)lu->tgt->guid,
  			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",
  	.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)
  {
  	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);
  