text: /*	$OpenBSD: aacvar.h,v 1.13 2016/04/01 04:16:27 jsg Exp $	*/
  
  /*-
   * Copyright (c) 2000 Michael Smith
   * Copyright (c) 2000 BSDi
   * Copyright (c) 2000 Niklas Hallqvist
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
   *	$FreeBSD: /c/ncvs/src/sys/dev/aac/aacvar.h,v 1.1 2000/09/13 03:20:34 msmith Exp $
   */
  
  /*
   * This driver would not have rewritten for OpenBSD if it was not for the
   * hardware donation from Nocom.  I want to thank them for their support.
   * Of course, credit should go to Mike Smith for the original work he did
   * in the FreeBSD driver where I found lots of inspiration.
   * - Niklas Hallqvist
   */
  
  /* Debugging */
  // #define AAC_DEBUG 0x0
  
  #ifdef AAC_DEBUG
  #define AAC_DPRINTF(mask, args) if (aac_debug & (mask)) printf args
  #define AAC_D_INTR	0x001
  #define AAC_D_MISC	0x002
  #define AAC_D_CMD	0x004
  #define AAC_D_QUEUE	0x008
  #define AAC_D_IO	0x010
  #define AAC_D_IOCTL	0x020
  #define AAC_D_LOCK	0x040
  #define AAC_D_THREAD	0x080
  #define AAC_D_FIB	0x100
  extern int aac_debug;
  
  #define AAC_PRINT_FIB(sc, fib)  do { \
  	if (aac_debug & AAC_D_FIB) \
  		aac_print_fib((sc), (fib), __func__); \
  } while (0)
  #else
  #define AAC_DPRINTF(mask, args)
  #define AAC_PRINT_FIB(sc, fib)
  #endif
  
  struct aac_code_lookup {
  	char	*string;
  	u_int32_t code;
  };
  
  struct aac_softc;
  
  /*
   * We allocate a small set of FIBs for the adapter to use to send us messages.
   */
  #define AAC_ADAPTER_FIBS	8
  
  /*
   * FIBs are allocated in page-size chunks and can grow up to the 512
   * limit imposed by the hardware.
   */
  #define AAC_FIB_COUNT		(PAGE_SIZE/sizeof(struct aac_fib))
  #define AAC_MAX_FIBS		512
  #define AAC_FIBMAP_SIZE		(PAGE_SIZE)
  
  /*
   * The controller reports status events in AIFs.  We hang on to a number of
   * these in order to pass them out to user-space management tools.
   */
  #define AAC_AIFQ_LENGTH		64
  
  /*
   * Firmware messages are passed in the printf buffer.
   */
  #define AAC_PRINTF_BUFSIZE	256
  
  /*
   * We wait this many seconds for the adapter to come ready if it is still
   * booting.
   */
  #define AAC_BOOT_TIMEOUT	(3 * 60)
  
  /*
   * Timeout for immediate commands.
   */
  #define AAC_IMMEDIATE_TIMEOUT	30
  
  /*
   * Timeout for normal commands
   */
  #define AAC_CMD_TIMEOUT		30		/* seconds */
  
  /*
   * Rate at which we periodically check for timed out commands and kick the
   * controller.
   */
  #define AAC_PERIODIC_INTERVAL	20		/* seconds */
  
  /*
   * Wait this long for a lost interrupt to get detected.
   */
  #define AAC_WATCH_TIMEOUT	10000		/* 10000 * 1ms = 10s */
  
  /*
   * Delay 20ms after the qnotify in sync operations.  Experimentally deduced.
   */
  #define AAC_SYNC_DELAY 20000
  
  /*
   * The firmware interface allows for a 16-bit s/g list length.  We limit 
   * ourselves to a reasonable maximum and ensure alignment.
   */
  #define AAC_MAXSGENTRIES	64	/* max S/G entries, limit 65535 */		
  
  /*
   * We gather a number of adapter-visible items into a single structure.
   *
   * The ordering of this structure may be important; we copy the Linux driver:
   *
   * Adapter FIBs
   * Init struct
   * Queue headers (Comm Area)
   * Printf buffer
   *
   * In addition, we add:
   * Sync Fib
   */
  struct aac_common {
  	/* fibs for the controller to send us messages */
  	struct aac_fib ac_fibs[AAC_ADAPTER_FIBS];
  
  	/* the init structure */
  	struct aac_adapter_init	ac_init;
  
  	/* arena within which the queue structures are kept */
  	u_int8_t ac_qbuf[sizeof(struct aac_queue_table) + AAC_QUEUE_ALIGN];
  
  	/* buffer for text messages from the controller */
  	char	ac_printf[AAC_PRINTF_BUFSIZE];
      
  	/* fib for synchronous commands */
  	struct aac_fib ac_sync_fib;
  };
  #define AAC_COMMON_ALLOCSIZE (8192 + sizeof(struct aac_common))
  
  /*
   * Interface operations
   */
  struct aac_interface {
  	int	(*aif_get_fwstatus)(struct aac_softc *);
  	void	(*aif_qnotify)(struct aac_softc *, int);
  	int	(*aif_get_istatus)(struct aac_softc *);
  	void	(*aif_set_istatus)(struct aac_softc *, int);
  	void	(*aif_set_mailbox)(struct aac_softc *, u_int32_t,
  	    u_int32_t, u_int32_t, u_int32_t, u_int32_t);
  	int	(*aif_get_mailbox)(struct aac_softc *, int mb);
  	void	(*aif_set_interrupts)(struct aac_softc *, int);
  };
  extern struct aac_interface aac_fa_interface;
  extern struct aac_interface aac_sa_interface;
  extern struct aac_interface aac_rx_interface;
  extern struct aac_interface aac_rkt_interface;
  
  #define AAC_GET_FWSTATUS(sc)		((sc)->aac_if.aif_get_fwstatus(sc))
  #define AAC_QNOTIFY(sc, qbit) \
  	((sc)->aac_if.aif_qnotify((sc), (qbit)))
  #define AAC_GET_ISTATUS(sc)		((sc)->aac_if.aif_get_istatus(sc))
  #define AAC_CLEAR_ISTATUS(sc, mask) \
  	((sc)->aac_if.aif_set_istatus((sc), (mask)))
  #define AAC_SET_MAILBOX(sc, command, arg0, arg1, arg2, arg3) \
  	do {								\
  		((sc)->aac_if.aif_set_mailbox((sc), (command), (arg0),	\
  		    (arg1), (arg2), (arg3)));				\
  	} while(0)
  #define AAC_GET_MAILBOX(sc, mb) \
  	((sc)->aac_if.aif_get_mailbox(sc, (mb)))
  #define	AAC_MASK_INTERRUPTS(sc)	\
  	((sc)->aac_if.aif_set_interrupts((sc), 0))
  #define AAC_UNMASK_INTERRUPTS(sc) \
  	((sc)->aac_if.aif_set_interrupts((sc), 1))
  
  #define AAC_SETREG4(sc, reg, val) \
  	bus_space_write_4((sc)->aac_memt, (sc)->aac_memh, (reg), (val))
  #define AAC_GETREG4(sc, reg) \
  	bus_space_read_4((sc)->aac_memt, (sc)->aac_memh, (reg))
  #define AAC_SETREG2(sc, reg, val) \
  	bus_space_write_2((sc)->aac_memt, (sc)->aac_memh, (reg), (val))
  #define AAC_GETREG2(sc, reg) \
  	bus_space_read_2((sc)->aac_memt, (sc)->aac_memh, (reg))
  #define AAC_SETREG1(sc, reg, val) \
  	bus_space_write_1((sc)->aac_memt, (sc)->aac_memh, (reg), (val))
  #define AAC_GETREG1(sc, reg) \
  	bus_space_read_1((sc)->aac_memt, (sc)->aac_memh, (reg))
  
  /* Define the OS version specific locks */
  typedef struct rwlock aac_lock_t;
  #define AAC_LOCK_INIT(l, s)	do { \
      rw_init((l), "aaclock"); \
      AAC_DPRINTF(AAC_D_LOCK, ("%s: init lock @%s: %d\n", \
  	        sc->aac_dev.dv_xname, __FUNCTION__, __LINE__)); \
  } while (0)
  
  #define AAC_LOCK_ACQUIRE(l) do { \
      AAC_DPRINTF(AAC_D_LOCK, ("%s: lock @%s: %d\n", \
  	        sc->aac_dev.dv_xname, __FUNCTION__, __LINE__)); \
      rw_enter_write((l)); \
  } while (0)
  
  #define AAC_LOCK_RELEASE(l) do { \
      rw_exit_write((l)); \
      AAC_DPRINTF(AAC_D_LOCK, ("%s: unlock @%s: %d\n", \
  	        sc->aac_dev.dv_xname, __FUNCTION__, __LINE__)); \
  } while (0)
  
  /*
   * Per-container data structure
   */
  struct aac_container
  {
  	struct aac_mntobj co_mntobj;
  	int				co_found;
  	TAILQ_ENTRY(aac_container)	co_link;
  };
  
  /*
   * A command contol block, one for each corresponding command index of the
   * controller.
   */
  struct aac_command
  {
  	TAILQ_ENTRY(aac_command) cm_link;	/* list linkage */
  
  	struct aac_softc	*cm_sc;		/* controller that owns us */
  
  	struct aac_fib 		*cm_fib;	/* FIB for this command */
  	bus_addr_t		cm_fibphys;	/* bus address of the FIB */
  	void			*cm_data;
  	size_t			cm_datalen;
  	bus_dmamap_t		cm_datamap;
  	struct aac_sg_table	*cm_sgtable;	/* pointer to s/g table */
  
  	u_int			cm_flags;
  #define AAC_CMD_MAPPED		(1<<0)	/* command has had its data mapped */
  #define AAC_CMD_DATAIN		(1<<1)	/* command involves data moving
  					 * from controller to host */
  #define AAC_CMD_DATAOUT		(1<<2)	/* command involves data moving
  					 * from host to controller */
  #define AAC_CMD_COMPLETED	(1<<3)	/* command has been completed */
  #define AAC_CMD_TIMEDOUT	(1<<4)	/* command taken too long */
  #define AAC_ON_AACQ_FREE	(1<<5)
  #define AAC_ON_AACQ_READY	(1<<6)
  #define AAC_ON_AACQ_BUSY	(1<<7)
  #define AAC_ON_AACQ_BIO		(1<<8)
  #define AAC_ON_AACQ_MASK	((1<<5)|(1<<6)|(1<<7)|(1<<8))
  #define AAC_QUEUE_FRZN		(1<<9)	/* Freeze the processing of
  					 * commands on the queue. */
  #define AAC_ACF_WATCHDOG 	(1<<10)
  
  	void			(*cm_complete)(struct aac_command *);
  	void			*cm_private;
  	u_int32_t		cm_blkno;
  	u_int32_t		cm_bcount;
  	time_t			cm_timestamp;	/* command creation time */
  	int			cm_queue;
  	int			cm_index;
  };
  
  struct aac_fibmap {
  	TAILQ_ENTRY(aac_fibmap) fm_link;	/* list linkage */
  	struct aac_fib		*aac_fibs;
  	bus_dmamap_t		aac_fibmap;
   	bus_dma_segment_t	aac_seg;
  	int			aac_nsegs;
  	struct aac_command	*aac_commands;
  };
  
  /*
   * Command queue statistics
   */
  #define AACQ_FREE       0
  #define AACQ_BIO        1
  #define AACQ_READY      2
  #define AACQ_BUSY       3
  #define AACQ_COUNT      4       /* total number of queues */
  
  struct aac_qstat {
          u_int32_t       q_length;
          u_int32_t       q_max;
  };
  
  /*
   * Per-controller structure.
   */
  struct aac_softc
  {
  	struct device aac_dev;
  	void   *aac_ih;
  	struct	scsi_link aac_link;	/* Virtual SCSI bus for cache devs */
  
  	bus_space_tag_t aac_memt;
  	bus_space_handle_t aac_memh;
  	bus_dma_tag_t aac_dmat;		/* parent DMA tag */
  
  	/* controller features, limits and status */
  	int	aac_state;
  #define AAC_STATE_SUSPEND	(1<<0)
  #define	AAC_STATE_OPEN		(1<<1)
  #define AAC_STATE_INTERRUPTS_ON	(1<<2)
  #define AAC_STATE_AIF_SLEEPER	(1<<3)
  	struct FsaRevision aac_revision;
  
  	int	aac_hwif;	/* controller hardware interface */
  #define AAC_HWIF_I960RX		0
  #define AAC_HWIF_STRONGARM	1
  #define AAC_HWIF_FALCON		2
  #define AAC_HWIF_RKT		3
  #define AAC_HWIF_UNKNOWN	-1
  
  	struct aac_common *aac_common;
  	bus_dmamap_t		aac_common_map;
  	u_int32_t aac_common_busaddr;
  	struct aac_interface aac_if;
  
  	/* command/fib resources */
  	TAILQ_HEAD(,aac_fibmap)	aac_fibmap_tqh;
  	u_int			total_fibs;
  	struct aac_command	*aac_commands;
  	struct scsi_iopool	aac_iopool;
  
  	/* command management */
  	struct mutex		 aac_free_mtx;
  	TAILQ_HEAD(,aac_command) aac_free;	/* command structures 
  						 * available for reuse */
  	TAILQ_HEAD(,aac_command) aac_ready;	/* commands on hold for
  						 * controller resources */
  	TAILQ_HEAD(,aac_command) aac_busy;
  	TAILQ_HEAD(,aac_command) aac_bio;
  
  	/* command management */
  	struct aac_queue_table *aac_queues;
  	struct aac_queue_entry *aac_qentries[AAC_QUEUE_COUNT];
  
  	struct aac_qstat	aac_qstat[AACQ_COUNT];	/* queue statistics */
  
  	/* connected containters */
  	TAILQ_HEAD(,aac_container)	aac_container_tqh;
  	aac_lock_t		aac_container_lock;
  
  	/* Protect the sync fib */
  #define AAC_SYNC_LOCK_FORCE	(1 << 0)
  	aac_lock_t		aac_sync_lock;
  
  	aac_lock_t		aac_io_lock;
  
  	struct {
  		u_int8_t hd_present;
  		u_int8_t hd_is_logdrv;
  		u_int8_t hd_is_arraydrv;
  		u_int8_t hd_is_master;
  		u_int8_t hd_is_parity;
  		u_int8_t hd_is_hotfix;
  		u_int8_t hd_master_no;
  		u_int8_t hd_lock;
  		u_int8_t hd_heads;
  		u_int8_t hd_secs;
  		u_int16_t hd_devtype;
  		u_int32_t hd_size;
  		u_int8_t hd_ldr_no;
  		u_int8_t hd_rw_attribs;
  		u_int32_t hd_start_sec;
  	} aac_hdr[AAC_MAX_CONTAINERS];
  	int			aac_container_count;
  
  	/* management interface */
  	aac_lock_t		aac_aifq_lock;
  	struct aac_aif_command	aac_aifq[AAC_AIFQ_LENGTH];
  	int			aac_aifq_head;
  	int			aac_aifq_tail;
  	struct selinfo		aac_select;
  	struct proc		*aifthread;
  	int			aifflags;
  #define AAC_AIFFLAGS_RUNNING	(1 << 0)
  #define AAC_AIFFLAGS_AIF	(1 << 1)
  #define	AAC_AIFFLAGS_EXIT	(1 << 2)
  #define AAC_AIFFLAGS_EXITED	(1 << 3)
  #define	AAC_AIFFLAGS_COMPLETE	(1 << 4)
  #define AAC_AIFFLAGS_PRINTF	(1 << 5)
  #define AAC_AIFFLAGS_PENDING	(AAC_AIFFLAGS_AIF | AAC_AIFFLAGS_COMPLETE | \
  				 AAC_AIFFLAGS_PRINTF)
  
  	u_int32_t		flags;
  #define AAC_FLAGS_PERC2QC	(1 << 0)
  #define	AAC_FLAGS_ENABLE_CAM	(1 << 1)	/* No SCSI passthrough */
  #define	AAC_FLAGS_CAM_NORESET	(1 << 2)	/* Fake SCSI resets */
  #define	AAC_FLAGS_CAM_PASSONLY	(1 << 3)	/* Only create pass devices */
  #define	AAC_FLAGS_SG_64BIT	(1 << 4)	/* Use 64-bit S/G addresses */
  #define	AAC_FLAGS_4GB_WINDOW	(1 << 5)	/* Device can access host mem
  						 * 2GB-4GB range */
  #define	AAC_FLAGS_NO4GB		(1 << 6)	/* Can't access host mem >2GB*/
  #define	AAC_FLAGS_256FIBS	(1 << 7)	/* Can only do 256 commands */
  #define	AAC_FLAGS_BROKEN_MEMMAP (1 << 8)	/* Broken HostPhysMemPages */
  
  	u_int32_t		supported_options;
  	int			aac_max_fibs;
  	void			*aac_sdh;
  };
  
  int	aac_attach(struct aac_softc *);
  int	aac_intr(void *);
  
  /* These all require correctly aligned buffers */
  static __inline__ void aac_enc16(u_int8_t *, u_int16_t);
  static __inline__ void aac_enc32(u_int8_t *, u_int32_t);
  static __inline__ u_int16_t aac_dec16(u_int8_t *);
  static __inline__ u_int32_t aac_dec32(u_int8_t *);
  
  static __inline__ void
  aac_enc16(addr, value)
  	u_int8_t *addr;
  	u_int16_t value;
  {
  	*(u_int16_t *)addr = htole16(value);
  }
  
  static __inline__ void
  aac_enc32(addr, value)
  	u_int8_t *addr;
  	u_int32_t value;
  {
  	*(u_int32_t *)addr = htole32(value);
  }
  
  static __inline__ u_int16_t
  aac_dec16(addr)
  	u_int8_t *addr;
  {
  	return letoh16(*(u_int16_t *)addr);
  }
  
  static __inline__ u_int32_t
  aac_dec32(addr)
  	u_int8_t *addr;
  {
  	return letoh32(*(u_int32_t *)addr);
  }
  
  /* Declarations copied from aac.c */
  #ifdef AAC_DEBUG
  void aac_print_fib(struct aac_softc *, struct aac_fib *, const char *);
  void aac_print_aif(struct aac_softc *, struct aac_aif_command *);
  #endif
  void aac_handle_aif(struct aac_softc *, struct aac_fib *);
  
  
  
  
  
  /*
   * Queue primitives for driver queues.
   */
  #define AACQ_ADD(sc, qname)					\
  	do {							\
  		struct aac_qstat *qs;				\
  								\
  		qs = &(sc)->aac_qstat[qname];			\
  								\
  		qs->q_length++;					\
  		if (qs->q_length > qs->q_max)			\
  			qs->q_max = qs->q_length;		\
  	} while (0)
  
  #define AACQ_REMOVE(sc, qname)    (sc)->aac_qstat[qname].q_length--
  #define AACQ_INIT(sc, qname)				\
  	do {						\
  		sc->aac_qstat[qname].q_length = 0;	\
  		sc->aac_qstat[qname].q_max = 0;		\
  	} while (0)
  
  
  #define AACQ_COMMAND_QUEUE(name, index)					\
  static __inline void							\
  aac_initq_ ## name (struct aac_softc *sc)				\
  {									\
  	TAILQ_INIT(&sc->aac_ ## name);					\
  	AACQ_INIT(sc, index);						\
  }									\
  static __inline void							\
  aac_enqueue_ ## name (struct aac_command *cm)				\
  {									\
  	AAC_DPRINTF(AAC_D_CMD, (": enqueue " #name));			\
  	if ((cm->cm_flags & AAC_ON_AACQ_MASK) != 0) {			\
  		printf("command %p is on another queue, flags = %#x\n",	\
  		       cm, cm->cm_flags);				\
  		panic("command is on another queue");			\
  	}								\
  	TAILQ_INSERT_TAIL(&cm->cm_sc->aac_ ## name, cm, cm_link);	\
  	cm->cm_flags |= AAC_ON_ ## index;				\
  	AACQ_ADD(cm->cm_sc, index);					\
  }									\
  static __inline void							\
  aac_requeue_ ## name (struct aac_command *cm)				\
  {									\
  	AAC_DPRINTF(AAC_D_CMD, (": requeue " #name));			\
  	if ((cm->cm_flags & AAC_ON_AACQ_MASK) != 0) {			\
  		printf("command %p is on another queue, flags = %#x\n",	\
  		       cm, cm->cm_flags);				\
  		panic("command is on another queue");			\
  	}								\
  	TAILQ_INSERT_HEAD(&cm->cm_sc->aac_ ## name, cm, cm_link);	\
  	cm->cm_flags |= AAC_ON_ ## index;				\
  	AACQ_ADD(cm->cm_sc, index);					\
  }									\
  static __inline struct aac_command *					\
  aac_dequeue_ ## name (struct aac_softc *sc)				\
  {									\
  	struct aac_command *cm;						\
  									\
  	if ((cm = TAILQ_FIRST(&sc->aac_ ## name)) != NULL) {		\
  		AAC_DPRINTF(AAC_D_CMD, (": dequeue " #name));		\
  		if ((cm->cm_flags & AAC_ON_ ## index) == 0) {		\
  			printf("dequeue - command %p not in queue, flags = %#x, "	\
  		       	       "bit = %#x\n", cm, cm->cm_flags,		\
  			       AAC_ON_ ## index);			\
  			panic("command not in queue");			\
  		}							\
  		TAILQ_REMOVE(&sc->aac_ ## name, cm, cm_link);		\
  		cm->cm_flags &= ~AAC_ON_ ## index;			\
  		AACQ_REMOVE(sc, index);					\
  	}								\
  	return(cm);							\
  }									\
  static __inline void							\
  aac_remove_ ## name (struct aac_command *cm)				\
  {									\
  	AAC_DPRINTF(AAC_D_CMD, (": remove " #name));			\
  	if ((cm->cm_flags & AAC_ON_ ## index) == 0) {			\
  		printf("remove - command %p not in queue, flags = %#x, "		\
  		       "bit = %#x\n", cm, cm->cm_flags, 		\
  		       AAC_ON_ ## index);				\
  		panic("command not in queue");				\
  	}								\
  	TAILQ_REMOVE(&cm->cm_sc->aac_ ## name, cm, cm_link);		\
  	cm->cm_flags &= ~AAC_ON_ ## index;				\
  	AACQ_REMOVE(cm->cm_sc, index);					\
  }									\
  struct hack
  
  AACQ_COMMAND_QUEUE(free, AACQ_FREE);
  AACQ_COMMAND_QUEUE(ready, AACQ_READY);
  AACQ_COMMAND_QUEUE(busy, AACQ_BUSY);
  AACQ_COMMAND_QUEUE(bio, AACQ_BIO);
  
  static __inline void
  aac_print_printf(struct aac_softc *sc)
  {
  	/*
  	 * XXX We have the ability to read the length of the printf string
  	 * from out of the mailboxes.
  	 */
  	printf("** %s: %.*s", sc->aac_dev.dv_xname, AAC_PRINTF_BUFSIZE,
  	       sc->aac_common->ac_printf);
  	sc->aac_common->ac_printf[0] = 0;
  	AAC_QNOTIFY(sc, AAC_DB_PRINTF);
  }
  