usr/src/sys/sparc/sparc/clockreg.h

/*
 * Copyright (c) 1992 The Regents of the University of California.
 * All rights reserved.
 *
 * This software was developed by the Computer Systems Engineering group
 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
 * contributed to Berkeley.
 *
 * %sccs.include.redist.c%
 *
 *      @(#)clockreg.h  7.1 (Berkeley) %G%
 *
 * from: $Header: clockreg.h,v 1.5 92/06/17 05:21:59 torek Exp $ (LBL)
 */

/*
 * Sun-4c clock Mostek TOD clock.  This includes the ``id prom''.
 */

/*
 * ID prom format.  The ``host id'' is set up by taking the machine
 * ID as the top byte and the hostid field as the remaining three.
 * The id_xxx0 field appears to contain some other number.  The id_xxx1
 * contains a bunch of 00's and a5's on my machines, suggesting it is
 * not actually used.  The checksum seems to include them, however.
 */
struct sun4c_idprom {
        u_char  id_format;              /* format identifier (= 1) */
        u_char  id_machine;             /* machine type (see cpu.h) */
        u_char  id_ether[6];            /* ethernet address */
        long    id_xxx0;                /* ??? */
        u_char  id_hostid[3];           /* ``host id'' bytes */
        u_char  id_checksum;            /* xor of everything else */
        char    id_xxx1[16];            /* ??? */
};

/*
 * Mostek MK48T02 clock.
 *
 * The clock includes 2040 bytes of RAM, the last 32 of which serve to
 * identify the kind of Sun 4c this is.
 */
struct clockreg {
        char    cl_nvram[2008];         /* `free' nonvolatile memory */
        struct  sun4c_idprom cl_idprom; /* `id prom' */
        volatile u_char cl_csr;         /* control register */
        volatile u_char cl_sec;         /* seconds (0..59; BCD) */
        volatile u_char cl_min;         /* minutes (0..59; BCD) */
        volatile u_char cl_hour;        /* hour (0..23; BCD) */
        volatile u_char cl_wday;        /* weekday (1..7) */
        volatile u_char cl_mday;        /* day in month (1..31; BCD) */
        volatile u_char cl_month;       /* month (1..12; BCD) */
        volatile u_char cl_year;        /* year (0..99; BCD) */
};

/* bits in cl_csr */
#define CLK_WRITE       0x80            /* want to write */
#define CLK_READ        0x40            /* want to read (freeze clock) */

struct clockreg *clockreg;

/*
 * Sun chose the year `68' as their base count, so that
 * cl_year==0 means 1968.
 */
#define YEAR0   68