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/*
* SGS M48-T59Y TOD/NVRAM Driver
*
* (C) Copyright 2000
* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
*
* (C) Copyright 1999, by Curt McDowell, 08-06-99, Broadcom Corp.
*
* (C) Copyright 2001, James Dougherty, 07/18/01, Broadcom Corp.
*
* SPDX-License-Identifier: GPL-2.0+
*/
/*
* SGS M48-T59Y TOD/NVRAM Driver
*
* The SGS M48 an 8K NVRAM starting at offset M48_BASE_ADDR and
* continuing for 8176 bytes. After that starts the Time-Of-Day (TOD)
* registers which are used to set/get the internal date/time functions.
*
* This module implements Y2K compliance by taking full year numbers
* and translating back and forth from the TOD 2-digit year.
*
* NOTE: for proper interaction with an operating system, the TOD should
* be used to store Universal Coordinated Time (GMT) and timezone
* conversions should be used.
*
* Here is a diagram of the memory layout:
*
* +---------------------------------------------+ 0xffe0a000
* | Non-volatile memory | .
* | | .
* | (8176 bytes of Non-volatile memory) | .
* | | .
* +---------------------------------------------+ 0xffe0bff0
* | Flags |
* +---------------------------------------------+ 0xffe0bff1
* | Unused |
* +---------------------------------------------+ 0xffe0bff2
* | Alarm Seconds |
* +---------------------------------------------+ 0xffe0bff3
* | Alarm Minutes |
* +---------------------------------------------+ 0xffe0bff4
* | Alarm Date |
* +---------------------------------------------+ 0xffe0bff5
* | Interrupts |
* +---------------------------------------------+ 0xffe0bff6
* | WatchDog |
* +---------------------------------------------+ 0xffe0bff7
* | Calibration |
* +---------------------------------------------+ 0xffe0bff8
* | Seconds |
* +---------------------------------------------+ 0xffe0bff9
* | Minutes |
* +---------------------------------------------+ 0xffe0bffa
* | Hours |
* +---------------------------------------------+ 0xffe0bffb
* | Day |
* +---------------------------------------------+ 0xffe0bffc
* | Date |
* +---------------------------------------------+ 0xffe0bffd
* | Month |
* +---------------------------------------------+ 0xffe0bffe
* | Year (2 digits only) |
* +---------------------------------------------+ 0xffe0bfff
*/
#include <common.h>
#include <rtc.h>
#include "mousse.h"
/*
* Imported from mousse.h:
*
* TOD_REG_BASE Base of m48t59y TOD registers
* SYS_TOD_UNPROTECT() Disable NVRAM write protect
* SYS_TOD_PROTECT() Re-enable NVRAM write protect
*/
#define YEAR 0xf
#define MONTH 0xe
#define DAY 0xd
#define DAY_OF_WEEK 0xc
#define HOUR 0xb
#define MINUTE 0xa
#define SECOND 0x9
#define CONTROL 0x8
#define WATCH 0x7
#define INTCTL 0x6
#define WD_DATE 0x5
#define WD_HOUR 0x4
#define WD_MIN 0x3
#define WD_SEC 0x2
#define _UNUSED 0x1
#define FLAGS 0x0
#define M48_ADDR ((volatile unsigned char *) TOD_REG_BASE)
int m48_tod_init(void)
{
SYS_TOD_UNPROTECT();
M48_ADDR[CONTROL] = 0;
M48_ADDR[WATCH] = 0;
M48_ADDR[INTCTL] = 0;
/*
* If the oscillator is currently stopped (as on a new part shipped
* from the factory), start it running.
*
* Here is an example of the TOD bytes on a brand new M48T59Y part:
* 00 00 00 00 00 00 00 00 00 88 8c c3 bf c8 f5 01
*/
if (M48_ADDR[SECOND] & 0x80)
M48_ADDR[SECOND] = 0;
/* Is battery low */
if ( M48_ADDR[FLAGS] & 0x10) {
printf("NOTICE: Battery low on Real-Time Clock (replace SNAPHAT).\n");
}
SYS_TOD_PROTECT();
return 0;
}
/*
* m48_tod_set
*/
static int to_bcd(int value)
{
return value / 10 * 16 + value % 10;
}
static int from_bcd(int value)
{
return value / 16 * 10 + value % 16;
}
static int day_of_week(int y, int m, int d) /* 0-6 ==> Sun-Sat */
{
static int t[] = {0, 3, 2, 5, 0, 3, 5, 1, 4, 6, 2, 4};
y -= m < 3;
return (y + y/4 - y/100 + y/400 + t[m-1] + d) % 7;
}
/*
* Note: the TOD should store the current GMT
*/
int m48_tod_set(int year, /* 1980-2079 */
int month, /* 01-12 */
int day, /* 01-31 */
int hour, /* 00-23 */
int minute, /* 00-59 */
int second) /* 00-59 */
{
SYS_TOD_UNPROTECT();
M48_ADDR[CONTROL] |= 0x80; /* Set WRITE bit */
M48_ADDR[YEAR] = to_bcd(year % 100);
M48_ADDR[MONTH] = to_bcd(month);
M48_ADDR[DAY] = to_bcd(day);
M48_ADDR[DAY_OF_WEEK] = day_of_week(year, month, day) + 1;
M48_ADDR[HOUR] = to_bcd(hour);
M48_ADDR[MINUTE] = to_bcd(minute);
M48_ADDR[SECOND] = to_bcd(second);
M48_ADDR[CONTROL] &= ~0x80; /* Clear WRITE bit */
SYS_TOD_PROTECT();
return 0;
}
/*
* Note: the TOD should store the current GMT
*/
int m48_tod_get(int *year, /* 1980-2079 */
int *month, /* 01-12 */
int *day, /* 01-31 */
int *hour, /* 00-23 */
int *minute, /* 00-59 */
int *second) /* 00-59 */
{
int y;
SYS_TOD_UNPROTECT();
M48_ADDR[CONTROL] |= 0x40; /* Set READ bit */
y = from_bcd(M48_ADDR[YEAR]);
*year = y < 80 ? 2000 + y : 1900 + y;
*month = from_bcd(M48_ADDR[MONTH]);
*day = from_bcd(M48_ADDR[DAY]);
/* day_of_week = M48_ADDR[DAY_OF_WEEK] & 0xf; */
*hour = from_bcd(M48_ADDR[HOUR]);
*minute = from_bcd(M48_ADDR[MINUTE]);
*second = from_bcd(M48_ADDR[SECOND] & 0x7f);
M48_ADDR[CONTROL] &= ~0x40; /* Clear READ bit */
SYS_TOD_PROTECT();
return 0;
}
int m48_tod_get_second(void)
{
return from_bcd(M48_ADDR[SECOND] & 0x7f);
}
/*
* Watchdog function
*
* If usec is 0, the watchdog timer is disarmed.
*
* If usec is non-zero, the watchdog timer is armed (or re-armed) for
* approximately usec microseconds (if the exact requested usec is
* not supported by the chip, the next higher available value is used).
*
* Minimum watchdog timeout = 62500 usec
* Maximum watchdog timeout = 124 sec (124000000 usec)
*/
void m48_watchdog_arm(int usec)
{
int mpy, res;
SYS_TOD_UNPROTECT();
if (usec == 0) {
res = 0;
mpy = 0;
} else if (usec < 2000000) { /* Resolution: 1/16s if below 2s */
res = 0;
mpy = (usec + 62499) / 62500;
} else if (usec < 8000000) { /* Resolution: 1/4s if below 8s */
res = 1;
mpy = (usec + 249999) / 250000;
} else if (usec < 32000000) { /* Resolution: 1s if below 32s */
res = 2;
mpy = (usec + 999999) / 1000000;
} else { /* Resolution: 4s up to 124s */
res = 3;
mpy = (usec + 3999999) / 4000000;
if (mpy > 31)
mpy = 31;
}
M48_ADDR[WATCH] = (0x80 | /* Steer to RST signal (IRQ = N/C) */
mpy << 2 |
res);
SYS_TOD_PROTECT();
}
/*
* U-Boot RTC support.
*/
int
rtc_get( struct rtc_time *tmp )
{
m48_tod_get(&tmp->tm_year,
&tmp->tm_mon,
&tmp->tm_mday,
&tmp->tm_hour,
&tmp->tm_min,
&tmp->tm_sec);
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 )
{
m48_tod_set(tmp->tm_year, /* 1980-2079 */
tmp->tm_mon, /* 01-12 */
tmp->tm_mday, /* 01-31 */
tmp->tm_hour, /* 00-23 */
tmp->tm_min, /* 00-59 */
tmp->tm_sec); /* 00-59 */
#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
return 0;
}
void
rtc_reset (void)
{
m48_tod_init();
}
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