/*
 * (C) Copyright 2002
 * ARIO Data Networks, Inc. dchiu@ariodata.com
 *
 * modified for DS164x:
 * The LEOX team <team@leox.org>, http://www.leox.org
 *
 * Based on MontaVista DS1743 code and U-Boot mc146818 code
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */

/*
 * Date & Time support for the DS164x RTC
 */

/* #define      RTC_DEBUG */

#include <common.h>
#include <command.h>
#include <rtc.h>


#if defined(CONFIG_CMD_DATE)

static uchar    rtc_read(unsigned int addr );
static void     rtc_write(unsigned int addr, uchar val);
static uchar    bin2bcd(unsigned int n);
static unsigned bcd2bin(uchar c);

#define RTC_EPOCH                 2000  /* century */

/*
 * DS164x registers layout
 */
#define RTC_BASE                ( CONFIG_SYS_NVRAM_BASE_ADDR + CONFIG_SYS_NVRAM_SIZE )

#define RTC_YEAR                ( RTC_BASE + 0x07 )
#define RTC_MONTH               ( RTC_BASE + 0x06 )
#define RTC_DAY_OF_MONTH        ( RTC_BASE + 0x05 )
#define RTC_DAY_OF_WEEK         ( RTC_BASE + 0x04 )
#define RTC_HOURS               ( RTC_BASE + 0x03 )
#define RTC_MINUTES             ( RTC_BASE + 0x02 )
#define RTC_SECONDS             ( RTC_BASE + 0x01 )
#define RTC_CONTROL             ( RTC_BASE + 0x00 )

#define RTC_CONTROLA            RTC_CONTROL     /* W=bit6, R=bit5 */
#define   RTC_CA_WRITE            0x80
#define   RTC_CA_READ             0x40
#define RTC_CONTROLB            RTC_SECONDS     /* OSC=bit7       */
#define   RTC_CB_OSC_DISABLE      0x80
#define RTC_CONTROLC            RTC_DAY_OF_WEEK /* FT=bit6        */
#define   RTC_CC_FREQ_TEST        0x40

/* ------------------------------------------------------------------------- */

int rtc_get( struct rtc_time *tmp )
{
        uchar sec, min, hour;
        uchar mday, wday, mon, year;

        uchar reg_a;

        reg_a = rtc_read( RTC_CONTROLA );
        /* lock clock registers for read */
        rtc_write( RTC_CONTROLA, ( reg_a | RTC_CA_READ ));

        sec     = rtc_read( RTC_SECONDS );
        min     = rtc_read( RTC_MINUTES );
        hour    = rtc_read( RTC_HOURS );
        mday    = rtc_read( RTC_DAY_OF_MONTH );
        wday    = rtc_read( RTC_DAY_OF_WEEK );
        mon     = rtc_read( RTC_MONTH );
        year    = rtc_read( RTC_YEAR );

        /* unlock clock registers after read */
        rtc_write( RTC_CONTROLA, ( reg_a & ~RTC_CA_READ ));

#ifdef RTC_DEBUG
        printf( "Get RTC year: %02x mon: %02x mday: %02x wday: %02x "
                "hr: %02x min: %02x sec: %02x\n",
                year, mon, mday, wday,
                hour, min, sec );
#endif
        tmp->tm_sec  = bcd2bin( sec  & 0x7F );
        tmp->tm_min  = bcd2bin( min  & 0x7F );
        tmp->tm_hour = bcd2bin( hour & 0x3F );
        tmp->tm_mday = bcd2bin( mday & 0x3F );
        tmp->tm_mon  = bcd2bin( mon  & 0x1F );
        tmp->tm_wday = bcd2bin( wday & 0x07 );

        /* glue year in century (2000) */
        tmp->tm_year = bcd2bin( year ) + RTC_EPOCH;

        tmp->tm_yday = 0;
        tmp->tm_isdst= 0;
#ifdef RTC_DEBUG
        printf( "Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
                tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
                tmp->tm_hour, tmp->tm_min, tmp->tm_sec );
#endif

        return 0;
}

int rtc_set( struct rtc_time *tmp )
{
        uchar reg_a;

#ifdef RTC_DEBUG
        printf( "Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
                tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
                tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
#endif
        /* lock clock registers for write */
        reg_a = rtc_read( RTC_CONTROLA );
        rtc_write( RTC_CONTROLA, ( reg_a | RTC_CA_WRITE ));

        rtc_write( RTC_MONTH, bin2bcd( tmp->tm_mon ));

        rtc_write( RTC_DAY_OF_WEEK, bin2bcd( tmp->tm_wday ));
        rtc_write( RTC_DAY_OF_MONTH, bin2bcd( tmp->tm_mday ));
        rtc_write( RTC_HOURS, bin2bcd( tmp->tm_hour ));
        rtc_write( RTC_MINUTES, bin2bcd( tmp->tm_min ));
        rtc_write( RTC_SECONDS, bin2bcd( tmp->tm_sec ));

        /* break year in century */
        rtc_write( RTC_YEAR, bin2bcd( tmp->tm_year % 100 ));

        /* unlock clock registers after read */
        rtc_write( RTC_CONTROLA, ( reg_a  & ~RTC_CA_WRITE ));

        return 0;
}

void rtc_reset (void)
{
        uchar reg_a, reg_b;

        reg_a = rtc_read( RTC_CONTROLA );
        reg_b = rtc_read( RTC_CONTROLB );

        if ( reg_b & RTC_CB_OSC_DISABLE )
        {
                printf( "real-time-clock was stopped. Now starting...\n" );
                reg_a |= RTC_CA_WRITE;
                reg_b &= ~RTC_CB_OSC_DISABLE;

                rtc_write( RTC_CONTROLA, reg_a );
                rtc_write( RTC_CONTROLB, reg_b );
        }

        /* make sure read/write clock register bits are cleared */
        reg_a &= ~( RTC_CA_WRITE | RTC_CA_READ );
        rtc_write( RTC_CONTROLA, reg_a );
}

/* ------------------------------------------------------------------------- */

static uchar rtc_read( unsigned int addr )
{
        uchar val = *(volatile unsigned char*)(addr);

#ifdef RTC_DEBUG
        printf( "rtc_read: %x:%x\n", addr, val );
#endif
        return( val );
}

static void rtc_write( unsigned int addr, uchar val )
{
#ifdef RTC_DEBUG
        printf( "rtc_write: %x:%x\n", addr, val );
#endif
        *(volatile unsigned char*)(addr) = val;
}

static unsigned bcd2bin (uchar n)
{
        return ((((n >> 4) & 0x0F) * 10) + (n & 0x0F));
}

static unsigned char bin2bcd (unsigned int n)
{
        return (((n / 10) << 4) | (n % 10));
}

#endif