/* esp_scsi.h: Defines and structures for the ESP drier.
   *
   * Copyright (C) 2007 David S. Miller (davem@davemloft.net)
   */
  
  #ifndef _ESP_SCSI_H
  #define _ESP_SCSI_H
  
  					/* Access    Description      Offset */
  #define ESP_TCLOW	0x00UL		/* rw  Low bits transfer count 0x00  */
  #define ESP_TCMED	0x01UL		/* rw  Mid bits transfer count 0x04  */
  #define ESP_FDATA	0x02UL		/* rw  FIFO data bits          0x08  */
  #define ESP_CMD		0x03UL		/* rw  SCSI command bits       0x0c  */
  #define ESP_STATUS	0x04UL		/* ro  ESP status register     0x10  */
  #define ESP_BUSID	ESP_STATUS	/* wo  BusID for sel/resel     0x10  */
  #define ESP_INTRPT	0x05UL		/* ro  Kind of interrupt       0x14  */
  #define ESP_TIMEO	ESP_INTRPT	/* wo  Timeout for sel/resel   0x14  */
  #define ESP_SSTEP	0x06UL		/* ro  Sequence step register  0x18  */
  #define ESP_STP		ESP_SSTEP	/* wo  Transfer period/sync    0x18  */
  #define ESP_FFLAGS	0x07UL		/* ro  Bits current FIFO info  0x1c  */
  #define ESP_SOFF	ESP_FFLAGS	/* wo  Sync offset             0x1c  */
  #define ESP_CFG1	0x08UL		/* rw  First cfg register      0x20  */
  #define ESP_CFACT	0x09UL		/* wo  Clock conv factor       0x24  */
  #define ESP_STATUS2	ESP_CFACT	/* ro  HME status2 register    0x24  */
  #define ESP_CTEST	0x0aUL		/* wo  Chip test register      0x28  */
  #define ESP_CFG2	0x0bUL		/* rw  Second cfg register     0x2c  */
  #define ESP_CFG3	0x0cUL		/* rw  Third cfg register      0x30  */
  #define ESP_TCHI	0x0eUL		/* rw  High bits transf count  0x38  */
  #define ESP_UID		ESP_TCHI	/* ro  Unique ID code          0x38  */
  #define FAS_RLO		ESP_TCHI	/* rw  HME extended counter    0x38  */
  #define ESP_FGRND	0x0fUL		/* rw  Data base for fifo      0x3c  */
  #define FAS_RHI		ESP_FGRND	/* rw  HME extended counter    0x3c  */
  
  #define SBUS_ESP_REG_SIZE	0x40UL
  
  /* Bitfield meanings for the above registers. */
  
  /* ESP config reg 1, read-write, found on all ESP chips */
  #define ESP_CONFIG1_ID        0x07      /* My BUS ID bits */
  #define ESP_CONFIG1_CHTEST    0x08      /* Enable ESP chip tests */
  #define ESP_CONFIG1_PENABLE   0x10      /* Enable parity checks */
  #define ESP_CONFIG1_PARTEST   0x20      /* Parity test mode enabled? */
  #define ESP_CONFIG1_SRRDISAB  0x40      /* Disable SCSI reset reports */
  #define ESP_CONFIG1_SLCABLE   0x80      /* Enable slow cable mode */
  
  /* ESP config reg 2, read-write, found only on esp100a+esp200+esp236 chips */
  #define ESP_CONFIG2_DMAPARITY 0x01      /* enable DMA Parity (200,236) */
  #define ESP_CONFIG2_REGPARITY 0x02      /* enable reg Parity (200,236) */
  #define ESP_CONFIG2_BADPARITY 0x04      /* Bad parity target abort  */
  #define ESP_CONFIG2_SCSI2ENAB 0x08      /* Enable SCSI-2 features (tgtmode) */
  #define ESP_CONFIG2_HI        0x10      /* High Impedance DREQ ???  */
  #define ESP_CONFIG2_HMEFENAB  0x10      /* HME features enable */
  #define ESP_CONFIG2_BCM       0x20      /* Enable byte-ctrl (236)   */
  #define ESP_CONFIG2_DISPINT   0x20      /* Disable pause irq (hme) */
  #define ESP_CONFIG2_FENAB     0x40      /* Enable features (fas100,216) */
  #define ESP_CONFIG2_SPL       0x40      /* Enable status-phase latch (236) */
  #define ESP_CONFIG2_MKDONE    0x40      /* HME magic feature */
  #define ESP_CONFIG2_HME32     0x80      /* HME 32 extended */
  #define ESP_CONFIG2_MAGIC     0xe0      /* Invalid bits... */
  
  /* ESP config register 3 read-write, found only esp236+fas236+fas100a+hme chips */
  #define ESP_CONFIG3_FCLOCK    0x01     /* FAST SCSI clock rate (esp100a/hme) */
  #define ESP_CONFIG3_TEM       0x01     /* Enable thresh-8 mode (esp/fas236)  */
  #define ESP_CONFIG3_FAST      0x02     /* Enable FAST SCSI     (esp100a/hme) */
  #define ESP_CONFIG3_ADMA      0x02     /* Enable alternate-dma (esp/fas236)  */
  #define ESP_CONFIG3_TENB      0x04     /* group2 SCSI2 support (esp100a/hme) */
  #define ESP_CONFIG3_SRB       0x04     /* Save residual byte   (esp/fas236)  */
  #define ESP_CONFIG3_TMS       0x08     /* Three-byte msg's ok  (esp100a/hme) */
  #define ESP_CONFIG3_FCLK      0x08     /* Fast SCSI clock rate (esp/fas236)  */
  #define ESP_CONFIG3_IDMSG     0x10     /* ID message checking  (esp100a/hme) */
  #define ESP_CONFIG3_FSCSI     0x10     /* Enable FAST SCSI     (esp/fas236)  */
  #define ESP_CONFIG3_GTM       0x20     /* group2 SCSI2 support (esp/fas236)  */
  #define ESP_CONFIG3_IDBIT3    0x20     /* Bit 3 of HME SCSI-ID (hme)         */
  #define ESP_CONFIG3_TBMS      0x40     /* Three-byte msg's ok  (esp/fas236)  */
  #define ESP_CONFIG3_EWIDE     0x40     /* Enable Wide-SCSI     (hme)         */
  #define ESP_CONFIG3_IMS       0x80     /* ID msg chk'ng        (esp/fas236)  */
  #define ESP_CONFIG3_OBPUSH    0x80     /* Push odd-byte to dma (hme)         */
  
  /* ESP command register read-write */
  /* Group 1 commands:  These may be sent at any point in time to the ESP
   *                    chip.  None of them can generate interrupts 'cept
   *                    the "SCSI bus reset" command if you have not disabled
   *                    SCSI reset interrupts in the config1 ESP register.
   */
  #define ESP_CMD_NULL          0x00     /* Null command, ie. a nop */
  #define ESP_CMD_FLUSH         0x01     /* FIFO Flush */
  #define ESP_CMD_RC            0x02     /* Chip reset */
  #define ESP_CMD_RS            0x03     /* SCSI bus reset */
  
  /* Group 2 commands:  ESP must be an initiator and connected to a target
   *                    for these commands to work.
   */
  #define ESP_CMD_TI            0x10     /* Transfer Information */
  #define ESP_CMD_ICCSEQ        0x11     /* Initiator cmd complete sequence */
  #define ESP_CMD_MOK           0x12     /* Message okie-dokie */
  #define ESP_CMD_TPAD          0x18     /* Transfer Pad */
  #define ESP_CMD_SATN          0x1a     /* Set ATN */
  #define ESP_CMD_RATN          0x1b     /* De-assert ATN */
  
  /* Group 3 commands:  ESP must be in the MSGOUT or MSGIN state and be connected
   *                    to a target as the initiator for these commands to work.
   */
  #define ESP_CMD_SMSG          0x20     /* Send message */
  #define ESP_CMD_SSTAT         0x21     /* Send status */
  #define ESP_CMD_SDATA         0x22     /* Send data */
  #define ESP_CMD_DSEQ          0x23     /* Discontinue Sequence */
  #define ESP_CMD_TSEQ          0x24     /* Terminate Sequence */
  #define ESP_CMD_TCCSEQ        0x25     /* Target cmd cmplt sequence */
  #define ESP_CMD_DCNCT         0x27     /* Disconnect */
  #define ESP_CMD_RMSG          0x28     /* Receive Message */
  #define ESP_CMD_RCMD          0x29     /* Receive Command */
  #define ESP_CMD_RDATA         0x2a     /* Receive Data */
  #define ESP_CMD_RCSEQ         0x2b     /* Receive cmd sequence */
  
  /* Group 4 commands:  The ESP must be in the disconnected state and must
   *                    not be connected to any targets as initiator for
   *                    these commands to work.
   */
  #define ESP_CMD_RSEL          0x40     /* Reselect */
  #define ESP_CMD_SEL           0x41     /* Select w/o ATN */
  #define ESP_CMD_SELA          0x42     /* Select w/ATN */
  #define ESP_CMD_SELAS         0x43     /* Select w/ATN & STOP */
  #define ESP_CMD_ESEL          0x44     /* Enable selection */
  #define ESP_CMD_DSEL          0x45     /* Disable selections */
  #define ESP_CMD_SA3           0x46     /* Select w/ATN3 */
  #define ESP_CMD_RSEL3         0x47     /* Reselect3 */
  
  /* This bit enables the ESP's DMA on the SBus */
  #define ESP_CMD_DMA           0x80     /* Do DMA? */
  
  /* ESP status register read-only */
  #define ESP_STAT_PIO          0x01     /* IO phase bit */
  #define ESP_STAT_PCD          0x02     /* CD phase bit */
  #define ESP_STAT_PMSG         0x04     /* MSG phase bit */
  #define ESP_STAT_PMASK        0x07     /* Mask of phase bits */
  #define ESP_STAT_TDONE        0x08     /* Transfer Completed */
  #define ESP_STAT_TCNT         0x10     /* Transfer Counter Is Zero */
  #define ESP_STAT_PERR         0x20     /* Parity error */
  #define ESP_STAT_SPAM         0x40     /* Real bad error */
  /* This indicates the 'interrupt pending' condition on esp236, it is a reserved
   * bit on other revs of the ESP.
   */
  #define ESP_STAT_INTR         0x80             /* Interrupt */
  
  /* The status register can be masked with ESP_STAT_PMASK and compared
   * with the following values to determine the current phase the ESP
   * (at least thinks it) is in.  For our purposes we also add our own
   * software 'done' bit for our phase management engine.
   */
  #define ESP_DOP   (0)                                       /* Data Out  */
  #define ESP_DIP   (ESP_STAT_PIO)                            /* Data In   */
  #define ESP_CMDP  (ESP_STAT_PCD)                            /* Command   */
  #define ESP_STATP (ESP_STAT_PCD|ESP_STAT_PIO)               /* Status    */
  #define ESP_MOP   (ESP_STAT_PMSG|ESP_STAT_PCD)              /* Message Out */
  #define ESP_MIP   (ESP_STAT_PMSG|ESP_STAT_PCD|ESP_STAT_PIO) /* Message In */
  
  /* HME only: status 2 register */
  #define ESP_STAT2_SCHBIT      0x01 /* Upper bits 3-7 of sstep enabled */
  #define ESP_STAT2_FFLAGS      0x02 /* The fifo flags are now latched */
  #define ESP_STAT2_XCNT        0x04 /* The transfer counter is latched */
  #define ESP_STAT2_CREGA       0x08 /* The command reg is active now */
  #define ESP_STAT2_WIDE        0x10 /* Interface on this adapter is wide */
  #define ESP_STAT2_F1BYTE      0x20 /* There is one byte at top of fifo */
  #define ESP_STAT2_FMSB        0x40 /* Next byte in fifo is most significant */
  #define ESP_STAT2_FEMPTY      0x80 /* FIFO is empty */
  
  /* ESP interrupt register read-only */
  #define ESP_INTR_S            0x01     /* Select w/o ATN */
  #define ESP_INTR_SATN         0x02     /* Select w/ATN */
  #define ESP_INTR_RSEL         0x04     /* Reselected */
  #define ESP_INTR_FDONE        0x08     /* Function done */
  #define ESP_INTR_BSERV        0x10     /* Bus service */
  #define ESP_INTR_DC           0x20     /* Disconnect */
  #define ESP_INTR_IC           0x40     /* Illegal command given */
  #define ESP_INTR_SR           0x80     /* SCSI bus reset detected */
  
  /* ESP sequence step register read-only */
  #define ESP_STEP_VBITS        0x07     /* Valid bits */
  #define ESP_STEP_ASEL         0x00     /* Selection&Arbitrate cmplt */
  #define ESP_STEP_SID          0x01     /* One msg byte sent */
  #define ESP_STEP_NCMD         0x02     /* Was not in command phase */
  #define ESP_STEP_PPC          0x03     /* Early phase chg caused cmnd
                                          * bytes to be lost
                                          */
  #define ESP_STEP_FINI4        0x04     /* Command was sent ok */
  
  /* Ho hum, some ESP's set the step register to this as well... */
  #define ESP_STEP_FINI5        0x05
  #define ESP_STEP_FINI6        0x06
  #define ESP_STEP_FINI7        0x07
  
  /* ESP chip-test register read-write */
  #define ESP_TEST_TARG         0x01     /* Target test mode */
  #define ESP_TEST_INI          0x02     /* Initiator test mode */
  #define ESP_TEST_TS           0x04     /* Tristate test mode */
  
  /* ESP unique ID register read-only, found on fas236+fas100a only */
  #define ESP_UID_F100A         0x00     /* ESP FAS100A  */
  #define ESP_UID_F236          0x02     /* ESP FAS236   */
  #define ESP_UID_REV           0x07     /* ESP revision */
  #define ESP_UID_FAM           0xf8     /* ESP family   */
  
  /* ESP fifo flags register read-only */
  /* Note that the following implies a 16 byte FIFO on the ESP. */
  #define ESP_FF_FBYTES         0x1f     /* Num bytes in FIFO */
  #define ESP_FF_ONOTZERO       0x20     /* offset ctr not zero (esp100) */
  #define ESP_FF_SSTEP          0xe0     /* Sequence step */
  
  /* ESP clock conversion factor register write-only */
  #define ESP_CCF_F0            0x00     /* 35.01MHz - 40MHz */
  #define ESP_CCF_NEVER         0x01     /* Set it to this and die */
  #define ESP_CCF_F2            0x02     /* 10MHz */
  #define ESP_CCF_F3            0x03     /* 10.01MHz - 15MHz */
  #define ESP_CCF_F4            0x04     /* 15.01MHz - 20MHz */
  #define ESP_CCF_F5            0x05     /* 20.01MHz - 25MHz */
  #define ESP_CCF_F6            0x06     /* 25.01MHz - 30MHz */
  #define ESP_CCF_F7            0x07     /* 30.01MHz - 35MHz */
  
  /* HME only... */
  #define ESP_BUSID_RESELID     0x10
  #define ESP_BUSID_CTR32BIT    0x40
  
  #define ESP_BUS_TIMEOUT        250     /* In milli-seconds */
  #define ESP_TIMEO_CONST       8192
  #define ESP_NEG_DEFP(mhz, cfact) \
          ((ESP_BUS_TIMEOUT * ((mhz) / 1000)) / (8192 * (cfact)))
  #define ESP_HZ_TO_CYCLE(hertz)  ((1000000000) / ((hertz) / 1000))
  #define ESP_TICK(ccf, cycle)  ((7682 * (ccf) * (cycle) / 1000))
  
  /* For slow to medium speed input clock rates we shoot for 5mb/s, but for high
   * input clock rates we try to do 10mb/s although I don't think a transfer can
   * even run that fast with an ESP even with DMA2 scatter gather pipelining.
   */
  #define SYNC_DEFP_SLOW            0x32   /* 5mb/s  */
  #define SYNC_DEFP_FAST            0x19   /* 10mb/s */
  
  struct esp_cmd_priv {
  	union {
  		dma_addr_t	dma_addr;
  		int		num_sg;
  	} u;
  
  	int			cur_residue;
  	struct scatterlist	*cur_sg;
  	int			tot_residue;
  };
  #define ESP_CMD_PRIV(CMD)	((struct esp_cmd_priv *)(&(CMD)->SCp))
  
  enum esp_rev {
  	ESP100     = 0x00,  /* NCR53C90 - very broken */
  	ESP100A    = 0x01,  /* NCR53C90A */
  	ESP236     = 0x02,
  	FAS236     = 0x03,
  	FAS100A    = 0x04,
  	FAST       = 0x05,
  	FASHME     = 0x06,
  };
  
  struct esp_cmd_entry {
  	struct list_head	list;
  
  	struct scsi_cmnd	*cmd;
  
  	unsigned int		saved_cur_residue;
  	struct scatterlist	*saved_cur_sg;
  	unsigned int		saved_tot_residue;
  
  	u8			flags;
  #define ESP_CMD_FLAG_WRITE	0x01 /* DMA is a write */
  #define ESP_CMD_FLAG_ABORT	0x02 /* being aborted */
  #define ESP_CMD_FLAG_AUTOSENSE	0x04 /* Doing automatic REQUEST_SENSE */
  
  	u8			tag[2];
  	u8			orig_tag[2];
  
  	u8			status;
  	u8			message;
  
  	unsigned char		*sense_ptr;
  	unsigned char		*saved_sense_ptr;
  	dma_addr_t		sense_dma;
  
  	struct completion	*eh_done;
  };
  
  /* XXX make this configurable somehow XXX */
  #define ESP_DEFAULT_TAGS	16
  
  #define ESP_MAX_TARGET		16
  #define ESP_MAX_LUN		8
  #define ESP_MAX_TAG		256
  
  struct esp_lun_data {
  	struct esp_cmd_entry	*non_tagged_cmd;
  	int			num_tagged;
  	int			hold;
  	struct esp_cmd_entry	*tagged_cmds[ESP_MAX_TAG];
  };
  
  struct esp_target_data {
  	/* These are the ESP_STP, ESP_SOFF, and ESP_CFG3 register values which
  	 * match the currently negotiated settings for this target.  The SCSI
  	 * protocol values are maintained in spi_{offset,period,wide}(starget).
  	 */
  	u8			esp_period;
  	u8			esp_offset;
  	u8			esp_config3;
  
  	u8			flags;
  #define ESP_TGT_WIDE		0x01
  #define ESP_TGT_DISCONNECT	0x02
  #define ESP_TGT_NEGO_WIDE	0x04
  #define ESP_TGT_NEGO_SYNC	0x08
  #define ESP_TGT_CHECK_NEGO	0x40
  #define ESP_TGT_BROKEN		0x80
  
  	/* When ESP_TGT_CHECK_NEGO is set, on the next scsi command to this
  	 * device we will try to negotiate the following parameters.
  	 */
  	u8			nego_goal_period;
  	u8			nego_goal_offset;
  	u8			nego_goal_width;
  	u8			nego_goal_tags;
  
  	struct scsi_target	*starget;
  };
  
  struct esp_event_ent {
  	u8			type;
  #define ESP_EVENT_TYPE_EVENT	0x01
  #define ESP_EVENT_TYPE_CMD	0x02
  	u8			val;
  
  	u8			sreg;
  	u8			seqreg;
  	u8			sreg2;
  	u8			ireg;
  	u8			select_state;
  	u8			event;
  	u8			__pad;
  };
  
  struct esp;
  struct esp_driver_ops {
  	/* Read and write the ESP 8-bit registers.  On some
  	 * applications of the ESP chip the registers are at 4-byte
  	 * instead of 1-byte intervals.
  	 */
  	void (*esp_write8)(struct esp *esp, u8 val, unsigned long reg);
  	u8 (*esp_read8)(struct esp *esp, unsigned long reg);
  
  	/* Map and unmap DMA memory.  Eventually the driver will be
  	 * converted to the generic DMA API as soon as SBUS is able to
  	 * cope with that.  At such time we can remove this.
  	 */
  	dma_addr_t (*map_single)(struct esp *esp, void *buf,
  				 size_t sz, int dir);
  	int (*map_sg)(struct esp *esp, struct scatterlist *sg,
  		      int num_sg, int dir);
  	void (*unmap_single)(struct esp *esp, dma_addr_t addr,
  			     size_t sz, int dir);
  	void (*unmap_sg)(struct esp *esp, struct scatterlist *sg,
  			 int num_sg, int dir);
  
  	/* Return non-zero if there is an IRQ pending.  Usually this
  	 * status bit lives in the DMA controller sitting in front of
  	 * the ESP.  This has to be accurate or else the ESP interrupt
  	 * handler will not run.
  	 */
  	int (*irq_pending)(struct esp *esp);
  
  	/* Return the maximum allowable size of a DMA transfer for a
  	 * given buffer.
  	 */
  	u32 (*dma_length_limit)(struct esp *esp, u32 dma_addr,
  				u32 dma_len);
  
  	/* Reset the DMA engine entirely.  On return, ESP interrupts
  	 * should be enabled.  Often the interrupt enabling is
  	 * controlled in the DMA engine.
  	 */
  	void (*reset_dma)(struct esp *esp);
  
  	/* Drain any pending DMA in the DMA engine after a transfer.
  	 * This is for writes to memory.
  	 */
  	void (*dma_drain)(struct esp *esp);
  
  	/* Invalidate the DMA engine after a DMA transfer.  */
  	void (*dma_invalidate)(struct esp *esp);
  
  	/* Setup an ESP command that will use a DMA transfer.
  	 * The 'esp_count' specifies what transfer length should be
  	 * programmed into the ESP transfer counter registers, whereas
  	 * the 'dma_count' is the length that should be programmed into
  	 * the DMA controller.  Usually they are the same.  If 'write'
  	 * is non-zero, this transfer is a write into memory.  'cmd'
  	 * holds the ESP command that should be issued by calling
  	 * scsi_esp_cmd() at the appropriate time while programming
  	 * the DMA hardware.
  	 */
  	void (*send_dma_cmd)(struct esp *esp, u32 dma_addr, u32 esp_count,
  			     u32 dma_count, int write, u8 cmd);
  
  	/* Return non-zero if the DMA engine is reporting an error
  	 * currently.
  	 */
  	int (*dma_error)(struct esp *esp);
  };
  
  #define ESP_MAX_MSG_SZ		8
  #define ESP_EVENT_LOG_SZ	32
  
  #define ESP_QUICKIRQ_LIMIT	100
  #define ESP_RESELECT_TAG_LIMIT	2500
  
  struct esp {
  	void __iomem		*regs;
  	void __iomem		*dma_regs;
  
  	const struct esp_driver_ops *ops;
  
  	struct Scsi_Host	*host;
  	void			*dev;
  
  	struct esp_cmd_entry	*active_cmd;
  
  	struct list_head	queued_cmds;
  	struct list_head	active_cmds;
  
  	u8			*command_block;
  	dma_addr_t		command_block_dma;
  
  	unsigned int		data_dma_len;
  
  	/* The following are used to determine the cause of an IRQ. Upon every
  	 * IRQ entry we synchronize these with the hardware registers.
  	 */
  	u8			sreg;
  	u8			seqreg;
  	u8			sreg2;
  	u8			ireg;
  
  	u32			prev_hme_dmacsr;
  	u8			prev_soff;
  	u8			prev_stp;
  	u8			prev_cfg3;
  	u8			__pad;
  
  	struct list_head	esp_cmd_pool;
  
  	struct esp_target_data	target[ESP_MAX_TARGET];
  
  	int			fifo_cnt;
  	u8			fifo[16];
  
  	struct esp_event_ent	esp_event_log[ESP_EVENT_LOG_SZ];
  	int			esp_event_cur;
  
  	u8			msg_out[ESP_MAX_MSG_SZ];
  	int			msg_out_len;
  
  	u8			msg_in[ESP_MAX_MSG_SZ];
  	int			msg_in_len;
  
  	u8			bursts;
  	u8			config1;
  	u8			config2;
  
  	u8			scsi_id;
  	u32			scsi_id_mask;
  
  	enum esp_rev		rev;
  
  	u32			flags;
  #define ESP_FLAG_DIFFERENTIAL	0x00000001
  #define ESP_FLAG_RESETTING	0x00000002
  #define ESP_FLAG_DOING_SLOWCMD	0x00000004
  #define ESP_FLAG_WIDE_CAPABLE	0x00000008
  #define ESP_FLAG_QUICKIRQ_CHECK	0x00000010
  #define ESP_FLAG_DISABLE_SYNC	0x00000020
  
  	u8			select_state;
  #define ESP_SELECT_NONE		0x00 /* Not selecting */
  #define ESP_SELECT_BASIC	0x01 /* Select w/o MSGOUT phase */
  #define ESP_SELECT_MSGOUT	0x02 /* Select with MSGOUT */
  
  	/* When we are not selecting, we are expecting an event.  */
  	u8			event;
  #define ESP_EVENT_NONE		0x00
  #define ESP_EVENT_CMD_START	0x01
  #define ESP_EVENT_CMD_DONE	0x02
  #define ESP_EVENT_DATA_IN	0x03
  #define ESP_EVENT_DATA_OUT	0x04
  #define ESP_EVENT_DATA_DONE	0x05
  #define ESP_EVENT_MSGIN		0x06
  #define ESP_EVENT_MSGIN_MORE	0x07
  #define ESP_EVENT_MSGIN_DONE	0x08
  #define ESP_EVENT_MSGOUT	0x09
  #define ESP_EVENT_MSGOUT_DONE	0x0a
  #define ESP_EVENT_STATUS	0x0b
  #define ESP_EVENT_FREE_BUS	0x0c
  #define ESP_EVENT_CHECK_PHASE	0x0d
  #define ESP_EVENT_RESET		0x10
  
  	/* Probed in esp_get_clock_params() */
  	u32			cfact;
  	u32			cfreq;
  	u32			ccycle;
  	u32			ctick;
  	u32			neg_defp;
  	u32			sync_defp;
  
  	/* Computed in esp_reset_esp() */
  	u32			max_period;
  	u32			min_period;
  	u32			radelay;
  
  	/* Slow command state.  */
  	u8			*cmd_bytes_ptr;
  	int			cmd_bytes_left;
  
  	struct completion	*eh_reset;
  
  	void			*dma;
  	int			dmarev;
  };
  
  /* A front-end driver for the ESP chip should do the following in
   * it's device probe routine:
   * 1) Allocate the host and private area using scsi_host_alloc()
   *    with size 'sizeof(struct esp)'.  The first argument to
   *    scsi_host_alloc() should be &scsi_esp_template.
   * 2) Set host->max_id as appropriate.
   * 3) Set esp->host to the scsi_host itself, and esp->dev
   *    to the device object pointer.
   * 4) Hook up esp->ops to the front-end implementation.
   * 5) If the ESP chip supports wide transfers, set ESP_FLAG_WIDE_CAPABLE
   *    in esp->flags.
   * 6) Map the DMA and ESP chip registers.
   * 7) DMA map the ESP command block, store the DMA address
   *    in esp->command_block_dma.
   * 8) Register the scsi_esp_intr() interrupt handler.
   * 9) Probe for and provide the following chip properties:
   *    esp->scsi_id (assign to esp->host->this_id too)
   *    esp->scsi_id_mask
   *    If ESP bus is differential, set ESP_FLAG_DIFFERENTIAL
   *    esp->cfreq
   *    DMA burst bit mask in esp->bursts, if necessary
   * 10) Perform any actions necessary before the ESP device can
   *     be programmed for the first time.  On some configs, for
   *     example, the DMA engine has to be reset before ESP can
   *     be programmed.
   * 11) If necessary, call dev_set_drvdata() as needed.
   * 12) Call scsi_esp_register() with prepared 'esp' structure
   *     and a device pointer if possible.
   * 13) Check scsi_esp_register() return value, release all resources
   *     if an error was returned.
   */
  extern struct scsi_host_template scsi_esp_template;
  extern int scsi_esp_register(struct esp *, struct device *);
  
  extern void scsi_esp_unregister(struct esp *);
  extern irqreturn_t scsi_esp_intr(int, void *);
  extern void scsi_esp_cmd(struct esp *, u8);
  
  #endif /* !(_ESP_SCSI_H) */