mesh.h

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/*
 * mesh.h: definitions for the driver for the MESH SCSI bus adaptor
 * (Macintosh Enhanced SCSI Hardware) found on Power Macintosh computers.
 *
 * Copyright (C) 1996 Paul Mackerras.
 */
#ifndef _MESH_H
#define _MESH_H

/*
 * Registers in the MESH controller.
 */

struct mesh_regs {
    unsigned char   count_lo;
    char pad0[15];
    unsigned char   count_hi;
    char pad1[15];
    unsigned char   fifo;
    char pad2[15];
    unsigned char   sequence;
    char pad3[15];
    unsigned char   bus_status0;
    char pad4[15];
    unsigned char   bus_status1;
    char pad5[15];
    unsigned char   fifo_count;
    char pad6[15];
    unsigned char   exception;
    char pad7[15];
    unsigned char   error;
    char pad8[15];
    unsigned char   intr_mask;
    char pad9[15];
    unsigned char   interrupt;
    char pad10[15];
    unsigned char   source_id;
    char pad11[15];
    unsigned char   dest_id;
    char pad12[15];
    unsigned char   sync_params;
    char pad13[15];
    unsigned char   mesh_id;
    char pad14[15];
    unsigned char   sel_timeout;
    char pad15[15];
};

/* Bits in the sequence register. */
#define SEQ_DMA_MODE    0x80    /* use DMA for data transfer */
#define SEQ_TARGET  0x40    /* put the controller into target mode */
#define SEQ_ATN     0x20    /* assert ATN signal */
#define SEQ_ACTIVE_NEG  0x10    /* use active negation on REQ/ACK */
#define SEQ_CMD     0x0f    /* command bits: */
#define SEQ_ARBITRATE   1   /*  get the bus */
#define SEQ_SELECT  2   /*  select a target */
#define SEQ_COMMAND 3   /*  send a command */
#define SEQ_STATUS  4   /*  receive status */
#define SEQ_DATAOUT 5   /*  send data */
#define SEQ_DATAIN  6   /*  receive data */
#define SEQ_MSGOUT  7   /*  send a message */
#define SEQ_MSGIN   8   /*  receive a message */
#define SEQ_BUSFREE 9   /*  look for bus free */
#define SEQ_ENBPARITY   0x0a    /*  enable parity checking */
#define SEQ_DISPARITY   0x0b    /*  disable parity checking */
#define SEQ_ENBRESEL    0x0c    /*  enable reselection */
#define SEQ_DISRESEL    0x0d    /*  disable reselection */
#define SEQ_RESETMESH   0x0e    /*  reset the controller */
#define SEQ_FLUSHFIFO   0x0f    /*  clear out the FIFO */

/* Bits in the bus_status0 and bus_status1 registers:
   these correspond directly to the SCSI bus control signals. */
#define BS0_REQ     0x20
#define BS0_ACK     0x10
#define BS0_ATN     0x08
#define BS0_MSG     0x04
#define BS0_CD      0x02
#define BS0_IO      0x01
#define BS1_RST     0x80
#define BS1_BSY     0x40
#define BS1_SEL     0x20

/* Bus phases defined by the bits in bus_status0 */
#define BS0_PHASE   (BS0_MSG+BS0_CD+BS0_IO)
#define BP_DATAOUT  0
#define BP_DATAIN   BS0_IO
#define BP_COMMAND  BS0_CD
#define BP_STATUS   (BS0_CD+BS0_IO)
#define BP_MSGOUT   (BS0_MSG+BS0_CD)
#define BP_MSGIN    (BS0_MSG+BS0_CD+BS0_IO)

/* Bits in the exception register. */
#define EXC_SELWATN 0x20    /* (as target) we were selected with ATN */
#define EXC_SELECTED    0x10    /* (as target) we were selected w/o ATN */
#define EXC_RESELECTED  0x08    /* (as initiator) we were reselected */
#define EXC_ARBLOST 0x04    /* we lost arbitration */
#define EXC_PHASEMM 0x02    /* SCSI phase mismatch */
#define EXC_SELTO   0x01    /* selection timeout */

/* Bits in the error register */
#define ERR_UNEXPDISC   0x40    /* target unexpectedly disconnected */
#define ERR_SCSIRESET   0x20    /* SCSI bus got reset on us */
#define ERR_SEQERR  0x10    /* we did something the chip didn't like */
#define ERR_PARITY  0x01    /* parity error was detected */

/* Bits in the interrupt and intr_mask registers */
#define INT_ERROR   0x04    /* error interrupt */
#define INT_EXCEPTION   0x02    /* exception interrupt */
#define INT_CMDDONE 0x01    /* command done interrupt */

/* Fields in the sync_params register */
#define SYNC_OFF(x) ((x) >> 4)  /* offset field */
#define SYNC_PER(x) ((x) & 0xf) /* period field */
#define SYNC_PARAMS(o, p)   (((o) << 4) | (p))
#define ASYNC_PARAMS    2   /* sync_params value for async xfers */

/*
 * Assuming a clock frequency of 50MHz:
 *
 * The transfer period with SYNC_PER(sync_params) == x
 * is (x + 2) * 40ns, except that x == 0 gives 100ns.
 *
 * The units of the sel_timeout register are 10ms.
 */


#endif /* _MESH_H */