/* * 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 #include #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(); }