/*      $NetBSD: clock.c,v 1.15 2025/05/17 17:27:21 tsutsui Exp $       */

/*
 * Copyright (c) 1988 University of Utah.
 * Copyright (c) 1982, 1990, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * the Systems Programming Group of the University of Utah Computer
 * Science Department.
 *
 * 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.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 *
 * from: Utah $Hdr: clock.c 1.18 91/01/21$
 *
 *      @(#)clock.c     8.2 (Berkeley) 1/12/94
 */

#include <sys/param.h>

#include <net/if_ether.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>

#include <hp300/stand/common/hilreg.h>

#include <hp300/dev/frodoreg.h>         /* for APCI offsets */
#include <hp300/dev/intioreg.h>         /* for frodo offsets */
#include <dev/ic/mc146818reg.h>
#include <dev/clock_subr.h>

#include <lib/libsa/stand.h>
#include <lib/libsa/net.h>
#include <hp300/stand/common/samachdep.h>

#define FEBRUARY        2

#define BBC_SET_REG     0xe0
#define BBC_WRITE_REG   0xc2
#define BBC_READ_REG    0xc3
#define NUM_BBC_REGS    12

#ifdef BBC_SLOW_GETSECS
#define NSKIP_READ_BBC  100
#endif

#define range_test(n, l, h)     if ((n) < (l) || (n) > (h)) return false
#define bbc_to_decimal(a,b)     (bbc_registers[a] * 10 + bbc_registers[b])

static uint8_t bbc_registers[13];
static struct hil_dev *bbcaddr = BBCADDR;

static volatile uint8_t *mcclock =
    (volatile uint8_t *)(INTIOBASE + FRODO_BASE + FRODO_CALENDAR);

static bool clock_to_gmt(satime_t *);

static void read_bbc(void);
static uint8_t read_bbc_reg(int);
static uint8_t mc_read(u_int);

satime_t
getsecs(void)
{
        static bool clockinited = false;
        satime_t timbuf = 0;

        if (!clock_to_gmt(&timbuf) && !clockinited)
                printf("WARNING: bad date in battery clock\n");
        clockinited = true;

        /* Battery clock does not store usec's, so forget about it. */
        return timbuf;
}

static bool
clock_to_gmt(satime_t *timbuf)
{
        int i;
        satime_t tmp;
        int year, month, day, hour, min, sec;
#ifdef BBC_SLOW_GETSECS
        static satime_t tim_prev = 0;
#endif

        if (machineid == HP_425 && mmuid == MMUID_425_E) {
                /* 425e uses mcclock on the frodo utility chip */
                while ((mc_read(MC_REGA) & MC_REGA_UIP) != 0)
                        continue;
                sec   = mc_read(MC_SEC);
                min   = mc_read(MC_MIN);
                hour  = mc_read(MC_HOUR);
                day   = mc_read(MC_DOM);
                month = mc_read(MC_MONTH);
                year  = mc_read(MC_YEAR) + 1900;
        } else {
#ifdef BBC_SLOW_GETSECS
                /*
                 * XXX:
                 * The read_bbc() function against HIL seems extremely slow.
                 * It was being called on every timeout check via getsecs()
                 * so it significantly slowed down loading a kernel via NFS.
                 * 
                 * In most cases (e.g., in common/if_le.c and libsa/net.c),
                 * timeout checks are performed using getsecs() in busy loops
                 * without any actual waiting. In such cases, it's not
                 * necessary to read the precise time from the RTC on
                 * every call.
                 */
                static int nskip = NSKIP_READ_BBC;

                if (tim_prev != 0 && nskip-- > 0) {
                        *timbuf = tim_prev;
                        return true;
                }
                nskip = NSKIP_READ_BBC;
#endif

                /* Use the traditional HIL bbc for all other models */
                read_bbc();

                sec = bbc_to_decimal(1, 0);
                min = bbc_to_decimal(3, 2);

                /*
                 * Hours are different for some reason. Makes no sense really.
                 */
                hour  = ((bbc_registers[5] & 0x03) * 10) + bbc_registers[4];
                day   = bbc_to_decimal(8, 7);
                month = bbc_to_decimal(10, 9);
                year  = bbc_to_decimal(12, 11) + 1900;
        }

        if (year < POSIX_BASE_YEAR)
                year += 100;

#ifdef CLOCK_DEBUG
        printf("clock todr: %u/%u/%u %u:%u:%u\n",
            year, month, day, hour, min, sec);
#endif

        range_test(hour, 0, 23);
        range_test(day, 1, 31);
        range_test(month, 1, 12);

        tmp = 0;

        for (i = POSIX_BASE_YEAR; i < year; i++)
                tmp += days_per_year(i);
        if (is_leap_year(year) && month > FEBRUARY)
                tmp++;

        for (i = 1; i < month; i++)
                tmp += days_in_month(i);

        tmp += (day - 1);
        tmp = ((tmp * 24 + hour) * 60 + min) * 60 + sec;

#ifdef BBC_SLOW_GETSECS
        tim_prev = tmp;
#endif
        *timbuf = tmp;
        return true;
}

static void
read_bbc(void)
{
        int i;
        bool read_okay;

        read_okay = false;
        while (!read_okay) {
                read_okay = true;
                for (i = 0; i <= NUM_BBC_REGS; i++)
                        bbc_registers[i] = read_bbc_reg(i);
                for (i = 0; i <= NUM_BBC_REGS; i++)
                        if (bbc_registers[i] != read_bbc_reg(i))
                                read_okay = false;
        }
}

static uint8_t
read_bbc_reg(int reg)
{
        uint8_t data = reg;

        if (bbcaddr != NULL) {
#if 0
                send_hil_cmd(bbcaddr, BBC_SET_REG, &data, 1, NULL);
                send_hil_cmd(bbcaddr, BBC_READ_REG, NULL, 0, &data);
#else
                HILWAIT(bbcaddr);
                bbcaddr->hil_cmd = BBC_SET_REG;
                HILWAIT(bbcaddr);
                bbcaddr->hil_data = data;
                HILWAIT(bbcaddr);
                bbcaddr->hil_cmd = BBC_READ_REG;
                HILDATAWAIT(bbcaddr);
                data = bbcaddr->hil_data;
#endif
        }
        return data;
}

uint8_t
mc_read(u_int reg)
{
        uint8_t datum;

        mcclock[0] = (uint8_t)reg;
        datum = mcclock[1 << 2];        /* frodo chip has 4 byte stride */

        return datum;
}