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Diffstat (limited to 'board/bmw/m48t59y.c')
| -rw-r--r-- | board/bmw/m48t59y.c | 323 |
1 files changed, 323 insertions, 0 deletions
diff --git a/board/bmw/m48t59y.c b/board/bmw/m48t59y.c new file mode 100644 index 0000000..469f1ad --- /dev/null +++ b/board/bmw/m48t59y.c @@ -0,0 +1,323 @@ +/* + * 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. + * + * 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 + */ + +/* + * 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 "bmw.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. + */ +void +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 +} + +void +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 + +} + +void +rtc_reset (void) +{ + m48_tod_init(); +} + |