325 lines
8.7 KiB
C
325 lines
8.7 KiB
C
/*
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* SGS M48-T59Y TOD/NVRAM Driver
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*
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* (C) Copyright 2000
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* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
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*
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* (C) Copyright 1999, by Curt McDowell, 08-06-99, Broadcom Corp.
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*
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* (C) Copyright 2001, James Dougherty, 07/18/01, Broadcom Corp.
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*
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* See file CREDITS for list of people who contributed to this
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* project.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*/
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/*
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* SGS M48-T59Y TOD/NVRAM Driver
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*
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* The SGS M48 an 8K NVRAM starting at offset M48_BASE_ADDR and
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* continuing for 8176 bytes. After that starts the Time-Of-Day (TOD)
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* registers which are used to set/get the internal date/time functions.
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*
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* This module implements Y2K compliance by taking full year numbers
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* and translating back and forth from the TOD 2-digit year.
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*
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* NOTE: for proper interaction with an operating system, the TOD should
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* be used to store Universal Coordinated Time (GMT) and timezone
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* conversions should be used.
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*
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* Here is a diagram of the memory layout:
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*
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* +---------------------------------------------+ 0xffe0a000
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* | Non-volatile memory | .
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* | | .
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* | (8176 bytes of Non-volatile memory) | .
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* | | .
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* +---------------------------------------------+ 0xffe0bff0
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* | Flags |
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* +---------------------------------------------+ 0xffe0bff1
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* | Unused |
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* +---------------------------------------------+ 0xffe0bff2
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* | Alarm Seconds |
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* +---------------------------------------------+ 0xffe0bff3
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* | Alarm Minutes |
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* +---------------------------------------------+ 0xffe0bff4
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* | Alarm Date |
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* +---------------------------------------------+ 0xffe0bff5
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* | Interrupts |
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* +---------------------------------------------+ 0xffe0bff6
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* | WatchDog |
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* +---------------------------------------------+ 0xffe0bff7
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* | Calibration |
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* +---------------------------------------------+ 0xffe0bff8
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* | Seconds |
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* +---------------------------------------------+ 0xffe0bff9
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* | Minutes |
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* +---------------------------------------------+ 0xffe0bffa
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* | Hours |
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* +---------------------------------------------+ 0xffe0bffb
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* | Day |
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* +---------------------------------------------+ 0xffe0bffc
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* | Date |
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* +---------------------------------------------+ 0xffe0bffd
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* | Month |
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* +---------------------------------------------+ 0xffe0bffe
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* | Year (2 digits only) |
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* +---------------------------------------------+ 0xffe0bfff
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*/
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#include <common.h>
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#include <rtc.h>
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#include "mousse.h"
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/*
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* Imported from mousse.h:
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*
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* TOD_REG_BASE Base of m48t59y TOD registers
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* SYS_TOD_UNPROTECT() Disable NVRAM write protect
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* SYS_TOD_PROTECT() Re-enable NVRAM write protect
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*/
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#define YEAR 0xf
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#define MONTH 0xe
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#define DAY 0xd
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#define DAY_OF_WEEK 0xc
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#define HOUR 0xb
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#define MINUTE 0xa
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#define SECOND 0x9
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#define CONTROL 0x8
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#define WATCH 0x7
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#define INTCTL 0x6
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#define WD_DATE 0x5
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#define WD_HOUR 0x4
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#define WD_MIN 0x3
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#define WD_SEC 0x2
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#define _UNUSED 0x1
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#define FLAGS 0x0
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#define M48_ADDR ((volatile unsigned char *) TOD_REG_BASE)
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int m48_tod_init(void)
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{
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SYS_TOD_UNPROTECT();
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M48_ADDR[CONTROL] = 0;
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M48_ADDR[WATCH] = 0;
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M48_ADDR[INTCTL] = 0;
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/*
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* If the oscillator is currently stopped (as on a new part shipped
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* from the factory), start it running.
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*
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* Here is an example of the TOD bytes on a brand new M48T59Y part:
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* 00 00 00 00 00 00 00 00 00 88 8c c3 bf c8 f5 01
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*/
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if (M48_ADDR[SECOND] & 0x80)
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M48_ADDR[SECOND] = 0;
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/* Is battery low */
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if ( M48_ADDR[FLAGS] & 0x10) {
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printf("NOTICE: Battery low on Real-Time Clock (replace SNAPHAT).\n");
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}
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SYS_TOD_PROTECT();
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return 0;
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}
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/*
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* m48_tod_set
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*/
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static int to_bcd(int value)
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{
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return value / 10 * 16 + value % 10;
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}
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static int from_bcd(int value)
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{
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return value / 16 * 10 + value % 16;
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}
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static int day_of_week(int y, int m, int d) /* 0-6 ==> Sun-Sat */
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{
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static int t[] = {0, 3, 2, 5, 0, 3, 5, 1, 4, 6, 2, 4};
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y -= m < 3;
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return (y + y/4 - y/100 + y/400 + t[m-1] + d) % 7;
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}
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/*
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* Note: the TOD should store the current GMT
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*/
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int m48_tod_set(int year, /* 1980-2079 */
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int month, /* 01-12 */
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int day, /* 01-31 */
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int hour, /* 00-23 */
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int minute, /* 00-59 */
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int second) /* 00-59 */
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{
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SYS_TOD_UNPROTECT();
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M48_ADDR[CONTROL] |= 0x80; /* Set WRITE bit */
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M48_ADDR[YEAR] = to_bcd(year % 100);
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M48_ADDR[MONTH] = to_bcd(month);
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M48_ADDR[DAY] = to_bcd(day);
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M48_ADDR[DAY_OF_WEEK] = day_of_week(year, month, day) + 1;
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M48_ADDR[HOUR] = to_bcd(hour);
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M48_ADDR[MINUTE] = to_bcd(minute);
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M48_ADDR[SECOND] = to_bcd(second);
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M48_ADDR[CONTROL] &= ~0x80; /* Clear WRITE bit */
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SYS_TOD_PROTECT();
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return 0;
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}
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/*
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* Note: the TOD should store the current GMT
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*/
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int m48_tod_get(int *year, /* 1980-2079 */
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int *month, /* 01-12 */
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int *day, /* 01-31 */
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int *hour, /* 00-23 */
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int *minute, /* 00-59 */
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int *second) /* 00-59 */
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{
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int y;
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SYS_TOD_UNPROTECT();
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M48_ADDR[CONTROL] |= 0x40; /* Set READ bit */
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y = from_bcd(M48_ADDR[YEAR]);
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*year = y < 80 ? 2000 + y : 1900 + y;
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*month = from_bcd(M48_ADDR[MONTH]);
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*day = from_bcd(M48_ADDR[DAY]);
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/* day_of_week = M48_ADDR[DAY_OF_WEEK] & 0xf; */
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*hour = from_bcd(M48_ADDR[HOUR]);
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*minute = from_bcd(M48_ADDR[MINUTE]);
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*second = from_bcd(M48_ADDR[SECOND] & 0x7f);
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M48_ADDR[CONTROL] &= ~0x40; /* Clear READ bit */
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SYS_TOD_PROTECT();
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return 0;
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}
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int m48_tod_get_second(void)
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{
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return from_bcd(M48_ADDR[SECOND] & 0x7f);
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}
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/*
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* Watchdog function
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*
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* If usec is 0, the watchdog timer is disarmed.
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*
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* If usec is non-zero, the watchdog timer is armed (or re-armed) for
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* approximately usec microseconds (if the exact requested usec is
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* not supported by the chip, the next higher available value is used).
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*
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* Minimum watchdog timeout = 62500 usec
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* Maximum watchdog timeout = 124 sec (124000000 usec)
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*/
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void m48_watchdog_arm(int usec)
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{
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int mpy, res;
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SYS_TOD_UNPROTECT();
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if (usec == 0) {
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res = 0;
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mpy = 0;
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} else if (usec < 2000000) { /* Resolution: 1/16s if below 2s */
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res = 0;
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mpy = (usec + 62499) / 62500;
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} else if (usec < 8000000) { /* Resolution: 1/4s if below 8s */
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res = 1;
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mpy = (usec + 249999) / 250000;
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} else if (usec < 32000000) { /* Resolution: 1s if below 32s */
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res = 2;
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mpy = (usec + 999999) / 1000000;
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} else { /* Resolution: 4s up to 124s */
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res = 3;
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mpy = (usec + 3999999) / 4000000;
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if (mpy > 31)
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mpy = 31;
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}
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M48_ADDR[WATCH] = (0x80 | /* Steer to RST signal (IRQ = N/C) */
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mpy << 2 |
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res);
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SYS_TOD_PROTECT();
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}
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/*
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* U-Boot RTC support.
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*/
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int
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rtc_get( struct rtc_time *tmp )
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{
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m48_tod_get(&tmp->tm_year,
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&tmp->tm_mon,
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&tmp->tm_mday,
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&tmp->tm_hour,
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&tmp->tm_min,
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&tmp->tm_sec);
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tmp->tm_yday = 0;
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tmp->tm_isdst= 0;
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#ifdef RTC_DEBUG
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printf( "Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
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tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
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tmp->tm_hour, tmp->tm_min, tmp->tm_sec );
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#endif
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return 0;
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}
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int rtc_set( struct rtc_time *tmp )
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{
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m48_tod_set(tmp->tm_year, /* 1980-2079 */
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tmp->tm_mon, /* 01-12 */
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tmp->tm_mday, /* 01-31 */
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tmp->tm_hour, /* 00-23 */
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tmp->tm_min, /* 00-59 */
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tmp->tm_sec); /* 00-59 */
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#ifdef RTC_DEBUG
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printf( "Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
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tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
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tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
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#endif
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return 0;
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}
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void
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rtc_reset (void)
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{
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m48_tod_init();
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}
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