/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2018 Gary Mills
 * Copyright 2012 Nexenta Systems, Inc.  All rights reserved.
 */
/*
 * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*      Copyright (c) 1990, 1991 UNIX System Laboratories, Inc. */
/*      Copyright (c) 1984, 1986, 1987, 1988, 1989, 1990 AT&T   */
/*        All Rights Reserved   */

/*      Copyright (c) 1987, 1988 Microsoft Corporation  */
/*        All Rights Reserved   */

#include <sys/param.h>
#include <sys/time.h>
#include <sys/systm.h>

#include <sys/cpuvar.h>
#include <sys/clock.h>
#include <sys/debug.h>
#include <sys/rtc.h>
#include <sys/archsystm.h>
#include <sys/sysmacros.h>
#include <sys/lockstat.h>
#include <sys/stat.h>
#include <sys/sunddi.h>
#include <sys/ddi.h>

#include <sys/acpi/acpi.h>
#include <sys/acpica.h>

static int todpc_rtcget(unsigned char *buf);
static void todpc_rtcput(unsigned char *buf);

#define CLOCK_RES       1000            /* 1 microsec in nanosecs */

int clock_res = CLOCK_RES;

/*
 * The minimum sleep time till an alarm can be fired.
 * This can be tuned in /etc/system, but if the value is too small,
 * there is a danger that it will be missed if it takes too long to
 * get from the set point to sleep.  Or that it can fire quickly, and
 * generate a power spike on the hardware.  And small values are
 * probably only usefull for test setups.
 */
int clock_min_alarm = 4;

/*
 * Machine-dependent clock routines.
 */

extern long gmt_lag;

struct rtc_offset {
        int8_t  loaded;
        uint8_t day_alrm;
        uint8_t mon_alrm;
        uint8_t century;
};

static struct rtc_offset pc_rtc_offset = {0, 0, 0, 0};


/*
 * Entry point for ACPI to pass RTC or other clock values that
 * are useful to TOD.
 */
void
pc_tod_set_rtc_offsets(ACPI_TABLE_FADT *fadt)
{
        int             ok = 0;

        /*
         * ASSERT is for debugging, but we don't want the machine
         * falling over because for some reason we didn't get a valid
         * pointer.
         */
        ASSERT(fadt);
        if (fadt == NULL) {
                return;
        }

        if (fadt->DayAlarm) {
                pc_rtc_offset.day_alrm = fadt->DayAlarm;
                ok = 1;
        }

        if (fadt->MonthAlarm) {
                pc_rtc_offset.mon_alrm = fadt->MonthAlarm;
                ok = 1;
        }

        if (fadt->Century) {
                pc_rtc_offset.century = fadt->Century;
                ok = 1;
        }

        pc_rtc_offset.loaded = ok;
}


/*
 * Write the specified time into the clock chip.
 * Must be called with tod_lock held.
 */
/*ARGSUSED*/
static void
todpc_set(tod_ops_t *top, timestruc_t ts)
{
        todinfo_t tod = utc_to_tod(ts.tv_sec - ggmtl());
        struct rtc_t rtc;

        ASSERT(MUTEX_HELD(&tod_lock));

        if (todpc_rtcget((unsigned char *)&rtc))
                return;

        /*
         * rtc bytes are in binary-coded decimal, so we have to convert.
         * We assume that we wrap the rtc year back to zero at 2000.
         */
        /* LINTED: YRBASE = 0 for x86 */
        tod.tod_year -= YRBASE;
        if (tod.tod_year >= 100) {
                tod.tod_year -= 100;
                rtc.rtc_century = BYTE_TO_BCD(20); /* 20xx year */
        } else
                rtc.rtc_century = BYTE_TO_BCD(19); /* 19xx year */
        rtc.rtc_yr      = BYTE_TO_BCD(tod.tod_year);
        rtc.rtc_mon     = BYTE_TO_BCD(tod.tod_month);
        rtc.rtc_dom     = BYTE_TO_BCD(tod.tod_day);
        /* dow < 10, so no conversion */
        rtc.rtc_dow     = (unsigned char)tod.tod_dow;
        rtc.rtc_hr      = BYTE_TO_BCD(tod.tod_hour);
        rtc.rtc_min     = BYTE_TO_BCD(tod.tod_min);
        rtc.rtc_sec     = BYTE_TO_BCD(tod.tod_sec);

        todpc_rtcput((unsigned char *)&rtc);
}

/*
 * Read the current time from the clock chip and convert to UNIX form.
 * Assumes that the year in the clock chip is valid.
 * Must be called with tod_lock held.
 */
/*ARGSUSED*/
static timestruc_t
todpc_get(tod_ops_t *top)
{
        timestruc_t ts;
        todinfo_t tod;
        struct rtc_t rtc;
        int compute_century;
        static int century_warn = 1; /* only warn once, not each time called */
        static int range_warn = 1;

        ASSERT(MUTEX_HELD(&tod_lock));

        if (todpc_rtcget((unsigned char *)&rtc)) {
                tod_status_set(TOD_GET_FAILED);
                return (hrestime);
        }

        /* assume that we wrap the rtc year back to zero at 2000 */
        tod.tod_year    = BCD_TO_BYTE(rtc.rtc_yr);
        if (tod.tod_year < 69) {
                if (range_warn && tod.tod_year > 38) {
                        cmn_err(CE_WARN, "hardware real-time clock is out "
                            "of range -- time needs to be reset");
                        range_warn = 0;
                }
                tod.tod_year += 100 + YRBASE; /* 20xx year */
                compute_century = 20;
        } else {
                /* LINTED: YRBASE = 0 for x86 */
                tod.tod_year += YRBASE; /* 19xx year */
                compute_century = 19;
        }
        if (century_warn && BCD_TO_BYTE(rtc.rtc_century) != compute_century) {
                cmn_err(CE_NOTE,
                    "The hardware real-time clock appears to have the "
                    "wrong century: %d.\nSolaris will still operate "
                    "correctly, but other OS's/firmware agents may "
                    "not.\nUse date(1) to set the date to the current "
                    "time to correct the RTC.",
                    BCD_TO_BYTE(rtc.rtc_century));
                century_warn = 0;
        }
        tod.tod_month   = BCD_TO_BYTE(rtc.rtc_mon);
        tod.tod_day     = BCD_TO_BYTE(rtc.rtc_dom);
        tod.tod_dow     = rtc.rtc_dow;  /* dow < 10, so no conversion needed */
        tod.tod_hour    = BCD_TO_BYTE(rtc.rtc_hr);
        tod.tod_min     = BCD_TO_BYTE(rtc.rtc_min);
        tod.tod_sec     = BCD_TO_BYTE(rtc.rtc_sec);

        /* read was successful so ensure failure flag is clear */
        tod_status_clear(TOD_GET_FAILED);

        ts.tv_sec = tod_to_utc(tod) + ggmtl();
        ts.tv_nsec = 0;

        return (ts);
}

#include <sys/promif.h>
/*
 * Write the specified wakeup alarm into the clock chip.
 * Must be called with tod_lock held.
 */
void
/*ARGSUSED*/
todpc_setalarm(tod_ops_t *top, int nsecs)
{
        struct rtc_t rtc;
        int delta, asec, amin, ahr, adom, amon;
        int day_alrm = pc_rtc_offset.day_alrm;
        int mon_alrm = pc_rtc_offset.mon_alrm;

        ASSERT(MUTEX_HELD(&tod_lock));

        /* A delay of zero is not allowed */
        if (nsecs == 0)
                return;

        /* Make sure that we delay no less than the minimum time */
        if (nsecs < clock_min_alarm)
                nsecs = clock_min_alarm;

        if (todpc_rtcget((unsigned char *)&rtc))
                return;

        /*
         * Compute alarm secs, mins and hrs, and where appropriate, dom
         * and mon.  rtc bytes are in binary-coded decimal, so we have
         * to convert.
         */
        delta = nsecs + BCD_TO_BYTE(rtc.rtc_sec);
        asec = delta % 60;

        delta = (delta / 60) + BCD_TO_BYTE(rtc.rtc_min);
        amin = delta % 60;

        delta = (delta / 60) + BCD_TO_BYTE(rtc.rtc_hr);
        ahr  = delta % 24;

        if (day_alrm == 0 && delta >= 24) {
                prom_printf("No day alarm - set to end of today!\n");
                asec = 59;
                amin = 59;
                ahr  = 23;
        } else {
                int mon = BCD_TO_BYTE(rtc.rtc_mon);
                static int dpm[] =
                    {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

                adom = (delta / 24) + BCD_TO_BYTE(rtc.rtc_dom);

                if (mon_alrm == 0) {
                        if (adom > dpm[mon]) {
                                prom_printf("No mon alarm - "
                                    "set to end of current month!\n");
                                asec = 59;
                                amin = 59;
                                ahr  = 23;
                                adom = dpm[mon];
                        }
                } else {
                        for (amon = mon;
                            amon <= 12 && adom > dpm[amon]; amon++) {
                                adom -= dpm[amon];
                        }
                        if (amon > 12) {
                                prom_printf("Alarm too far in future - "
                                    "set to end of current year!\n");
                                asec = 59;
                                amin = 59;
                                ahr  = 23;
                                adom = dpm[12];
                                amon = 12;
                        }
                        rtc.rtc_amon = BYTE_TO_BCD(amon);
                }

                rtc.rtc_adom = BYTE_TO_BCD(adom);
        }

        rtc.rtc_asec = BYTE_TO_BCD(asec);
        rtc.rtc_amin = BYTE_TO_BCD(amin);
        rtc.rtc_ahr  = BYTE_TO_BCD(ahr);

        rtc.rtc_statusb |= RTC_AIE;     /* Enable alarm interrupt */

        todpc_rtcput((unsigned char *)&rtc);
}

/*
 * Clear an alarm.  This is effectively setting an alarm of 0.
 */
void
/*ARGSUSED*/
todpc_clralarm(tod_ops_t *top)
{
        mutex_enter(&tod_lock);
        todpc_setalarm(top, 0);
        mutex_exit(&tod_lock);
}

/*
 * Routine to read contents of real time clock to the specified buffer.
 * Returns ENXIO if clock not valid, or EAGAIN if clock data cannot be read
 * else 0.
 * Some RTC hardware is very slow at asserting the validity flag on
 * startup.  The routine will busy wait for the RTC to become valid.
 * The routine will also busy wait for the Update-In-Progress flag to clear.
 * On completion of the reads the Seconds register is re-read and the
 * UIP flag is rechecked to confirm that an clock update did not occur
 * during the accesses.  Routine will error exit after 256 attempts.
 * (See bugid 1158298.)
 * Routine returns RTC_NREG (which is 15) bytes of data, as given in the
 * technical reference.  This data includes both time and status registers.
 */

static int
todpc_rtcget(unsigned char *buf)
{
        unsigned char   reg;
        int             i;
        int             uip_try = 256;
        int             vrt_try = 512;
        unsigned char   *rawp;
        unsigned char   century = RTC_CENTURY;
        unsigned char   day_alrm;
        unsigned char   mon_alrm;

        ASSERT(MUTEX_HELD(&tod_lock));

        day_alrm = pc_rtc_offset.day_alrm;
        mon_alrm = pc_rtc_offset.mon_alrm;
        if (pc_rtc_offset.century != 0) {
                century = pc_rtc_offset.century;
        }

        for (;;) {
                if (vrt_try-- < 0)
                        return (ENXIO);
                outb(RTC_ADDR, RTC_D);          /* check if clock valid */
                reg = inb(RTC_DATA);
                if ((reg & RTC_VRT) != 0)
                        break;
                drv_usecwait(5000);             /* Delay for 5000 us */
        }


checkuip:
        if (uip_try-- < 0)
                return (EAGAIN);
        outb(RTC_ADDR, RTC_A);          /* check if update in progress */
        reg = inb(RTC_DATA);
        if (reg & RTC_UIP) {
                tenmicrosec();
                goto checkuip;
        }

        for (i = 0, rawp = buf; i < RTC_NREG; i++) {
                outb(RTC_ADDR, i);
                *rawp++ = inb(RTC_DATA);
        }
        outb(RTC_ADDR, century); /* do century */
        ((struct rtc_t *)buf)->rtc_century = inb(RTC_DATA);

        if (day_alrm > 0) {
                outb(RTC_ADDR, day_alrm);
                ((struct rtc_t *)buf)->rtc_adom = inb(RTC_DATA) & 0x3f;
        }
        if (mon_alrm > 0) {
                outb(RTC_ADDR, mon_alrm);
                ((struct rtc_t *)buf)->rtc_amon = inb(RTC_DATA);
        }

        outb(RTC_ADDR, 0);              /* re-read Seconds register */
        reg = inb(RTC_DATA);
        if (reg != ((struct rtc_t *)buf)->rtc_sec ||
            (((struct rtc_t *)buf)->rtc_statusa & RTC_UIP))
                /* update occured during reads */
                goto checkuip;

        return (0);
}

/*
 * This routine writes the contents of the given buffer to the real time
 * clock.  It is given RTC_NREGP bytes of data, which are the 10 bytes used
 * to write the time and set the alarm.  It should be called with the priority
 * raised to 5.
 */
static void
todpc_rtcput(unsigned char *buf)
{
        unsigned char   reg;
        int             i;
        unsigned char   century = RTC_CENTURY;
        unsigned char   day_alrm = pc_rtc_offset.day_alrm;
        unsigned char   mon_alrm = pc_rtc_offset.mon_alrm;
        unsigned char   tmp;

        if (pc_rtc_offset.century != 0) {
                century = pc_rtc_offset.century;
        }

        outb(RTC_ADDR, RTC_B);
        reg = inb(RTC_DATA);
        outb(RTC_ADDR, RTC_B);
        outb(RTC_DATA, reg | RTC_SET);  /* allow time set now */
        for (i = 0; i < RTC_NREGP; i++) { /* set the time */
                outb(RTC_ADDR, i);
                outb(RTC_DATA, buf[i]);
        }
        outb(RTC_ADDR, century); /* do century */
        outb(RTC_DATA, ((struct rtc_t *)buf)->rtc_century);

        if (day_alrm > 0) {
                outb(RTC_ADDR, day_alrm);
                /* preserve RTC_VRT bit; some virt envs accept writes there */
                tmp = inb(RTC_DATA) & RTC_VRT;
                tmp |= ((struct rtc_t *)buf)->rtc_adom & ~RTC_VRT;
                outb(RTC_DATA, tmp);
        }
        if (mon_alrm > 0) {
                outb(RTC_ADDR, mon_alrm);
                outb(RTC_DATA, ((struct rtc_t *)buf)->rtc_amon);
        }

        outb(RTC_ADDR, RTC_B);
        reg = inb(RTC_DATA);
        outb(RTC_ADDR, RTC_B);
        outb(RTC_DATA, reg & ~RTC_SET); /* allow time update */
}

static tod_ops_t todpc_ops = {
        TOD_OPS_VERSION,
        todpc_get,
        todpc_set,
        NULL,
        NULL,
        todpc_setalarm,
        todpc_clralarm,
        NULL
};

/*
 * Initialize for the default TOD ops vector for use on hardware.
 */

tod_ops_t *tod_ops = &todpc_ops;