171 lines
3.6 KiB
C
171 lines
3.6 KiB
C
/*
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* Copyright 2001 MontaVista Software Inc.
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* Author: jsun@mvista.com or jsun@junsun.net
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*
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* arch/mips/ddb5xxx/common/rtc_ds1386.c
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* low-level RTC hookups for s for Dallas 1396 chip.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*/
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/*
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* This file exports a function, rtc_ds1386_init(), which expects an
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* uncached base address as the argument. It will set the two function
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* pointers expected by the MIPS generic timer code.
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*/
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#include <linux/types.h>
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#include <linux/time.h>
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#include <linux/bcd.h>
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#include <asm/time.h>
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#include <asm/addrspace.h>
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#include <asm/mc146818rtc.h>
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#include <asm/debug.h>
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#define EPOCH 2000
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#define READ_RTC(x) *(volatile unsigned char*)(rtc_base+x)
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#define WRITE_RTC(x, y) *(volatile unsigned char*)(rtc_base+x) = y
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static unsigned long rtc_base;
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static unsigned long
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rtc_ds1386_get_time(void)
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{
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u8 byte;
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u8 temp;
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unsigned int year, month, day, hour, minute, second;
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unsigned long flags;
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spin_lock_irqsave(&rtc_lock, flags);
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/* let us freeze external registers */
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byte = READ_RTC(0xB);
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byte &= 0x3f;
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WRITE_RTC(0xB, byte);
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/* read time data */
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year = BCD2BIN(READ_RTC(0xA)) + EPOCH;
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month = BCD2BIN(READ_RTC(0x9) & 0x1f);
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day = BCD2BIN(READ_RTC(0x8));
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minute = BCD2BIN(READ_RTC(0x2));
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second = BCD2BIN(READ_RTC(0x1));
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/* hour is special - deal with it later */
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temp = READ_RTC(0x4);
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/* enable time transfer */
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byte |= 0x80;
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WRITE_RTC(0xB, byte);
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spin_unlock_irqrestore(&rtc_lock, flags);
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/* calc hour */
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if (temp & 0x40) {
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/* 12 hour format */
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hour = BCD2BIN(temp & 0x1f);
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if (temp & 0x20) hour += 12; /* PM */
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} else {
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/* 24 hour format */
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hour = BCD2BIN(temp & 0x3f);
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}
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return mktime(year, month, day, hour, minute, second);
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}
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static int
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rtc_ds1386_set_time(unsigned long t)
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{
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struct rtc_time tm;
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u8 byte;
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u8 temp;
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u8 year, month, day, hour, minute, second;
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unsigned long flags;
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spin_lock_irqsave(&rtc_lock, flags);
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/* let us freeze external registers */
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byte = READ_RTC(0xB);
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byte &= 0x3f;
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WRITE_RTC(0xB, byte);
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/* convert */
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to_tm(t, &tm);
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/* check each field one by one */
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year = BIN2BCD(tm.tm_year - EPOCH);
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if (year != READ_RTC(0xA)) {
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WRITE_RTC(0xA, year);
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}
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temp = READ_RTC(0x9);
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month = BIN2BCD(tm.tm_mon+1); /* tm_mon starts from 0 to 11 */
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if (month != (temp & 0x1f)) {
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WRITE_RTC( 0x9,
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(month & 0x1f) | (temp & ~0x1f) );
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}
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day = BIN2BCD(tm.tm_mday);
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if (day != READ_RTC(0x8)) {
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WRITE_RTC(0x8, day);
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}
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temp = READ_RTC(0x4);
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if (temp & 0x40) {
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/* 12 hour format */
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hour = 0x40;
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if (tm.tm_hour > 12) {
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hour |= 0x20 | (BIN2BCD(hour-12) & 0x1f);
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} else {
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hour |= BIN2BCD(tm.tm_hour);
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}
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} else {
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/* 24 hour format */
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hour = BIN2BCD(tm.tm_hour) & 0x3f;
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}
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if (hour != temp) WRITE_RTC(0x4, hour);
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minute = BIN2BCD(tm.tm_min);
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if (minute != READ_RTC(0x2)) {
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WRITE_RTC(0x2, minute);
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}
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second = BIN2BCD(tm.tm_sec);
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if (second != READ_RTC(0x1)) {
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WRITE_RTC(0x1, second);
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}
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spin_unlock_irqrestore(&rtc_lock, flags);
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return 0;
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}
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void
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rtc_ds1386_init(unsigned long base)
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{
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unsigned char byte;
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/* remember the base */
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rtc_base = base;
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db_assert((rtc_base & 0xe0000000) == KSEG1);
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/* turn on RTC if it is not on */
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byte = READ_RTC(0x9);
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if (byte & 0x80) {
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byte &= 0x7f;
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WRITE_RTC(0x9, byte);
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}
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/* enable time transfer */
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byte = READ_RTC(0xB);
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byte |= 0x80;
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WRITE_RTC(0xB, byte);
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/* set the function pointers */
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rtc_get_time = rtc_ds1386_get_time;
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rtc_set_time = rtc_ds1386_set_time;
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}
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