[SCSI] SUNESP: Complete driver rewrite to version 2.0

Major features:

1) Tagged queuing support.
2) Will properly negotiate for synchronous transfers even on
   devices that reject the wide negotiation message, such as
   CDROMs
3) Significantly lower kernel stack usage in interrupt
   handler path by elimination of function vector arrays,
   replaced by a top-level switch statement state machine.
4) Uses generic scsi infrastructure as much as possible to
   avoid code duplication.
5) Automatic request of sense data in response to CHECK_CONDITION
6) Portable to other platforms using ESP such as DEC and Sun3
   systems.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 560 insertions, 0 deletions

diff --git a/drivers/scsi/esp_scsi.h b/drivers/scsi/esp_scsi.h
new file mode 100644
index 00000000000..8d4a6690401
--- /dev/null
+++ b/drivers/scsi/esp_scsi.h
@@ -0,0 +1,560 @@
+/* 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_MHZ_TO_CYCLE(mhertz)  ((1000000000) / ((mhertz) / 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;
+
+        unsigned int            cur_residue;
+        struct scatterlist      *cur_sg;
+        unsigned 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                      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);
+
+        /* 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
+
+        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;
+
+        struct sbus_dma         *dma;
+};
+
+#define host_to_esp(host)       ((struct esp *)(host)->hostdata)
+
+/* 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) */