368dd5acd1
Implement the Panasonic MN10300 AM34 CPU subarch and implement SMP support for MN10300. Also implement support for the MN2WS0060 processor and the ASB2364 evaluation board which are AM34 based. Signed-off-by: Akira Takeuchi <takeuchi.akr@jp.panasonic.com> Signed-off-by: Kiyoshi Owada <owada.kiyoshi@jp.panasonic.com> Signed-off-by: David Howells <dhowells@redhat.com>
133 lines
3.9 KiB
C
133 lines
3.9 KiB
C
/* MN10300 RTC management
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*
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* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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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 Licence
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* as published by the Free Software Foundation; either version
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* 2 of the Licence, or (at your option) any later version.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/mc146818rtc.h>
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#include <linux/bcd.h>
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#include <linux/timex.h>
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#include <asm/rtc-regs.h>
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#include <asm/rtc.h>
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DEFINE_SPINLOCK(rtc_lock);
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EXPORT_SYMBOL(rtc_lock);
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/*
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* Read the current RTC time
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*/
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void read_persistent_clock(struct timespec *ts)
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{
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struct rtc_time tm;
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get_rtc_time(&tm);
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ts->tv_nsec = 0;
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ts->tv_sec = mktime(tm.tm_year, tm.tm_mon, tm.tm_mday,
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tm.tm_hour, tm.tm_min, tm.tm_sec);
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/* if rtc is way off in the past, set something reasonable */
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if (ts->tv_sec < 0)
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ts->tv_sec = mktime(2009, 1, 1, 12, 0, 0);
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}
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/*
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* In order to set the CMOS clock precisely, set_rtc_mmss has to be called 500
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* ms after the second nowtime has started, because when nowtime is written
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* into the registers of the CMOS clock, it will jump to the next second
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* precisely 500 ms later. Check the Motorola MC146818A or Dallas DS12887 data
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* sheet for details.
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*
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* BUG: This routine does not handle hour overflow properly; it just
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* sets the minutes. Usually you'll only notice that after reboot!
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*/
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static int set_rtc_mmss(unsigned long nowtime)
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{
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unsigned char save_control, save_freq_select;
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int retval = 0;
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int real_seconds, real_minutes, cmos_minutes;
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/* gets recalled with irq locally disabled */
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spin_lock(&rtc_lock);
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save_control = CMOS_READ(RTC_CONTROL); /* tell the clock it's being
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* set */
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CMOS_WRITE(save_control | RTC_SET, RTC_CONTROL);
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save_freq_select = CMOS_READ(RTC_FREQ_SELECT); /* stop and reset
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* prescaler */
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CMOS_WRITE(save_freq_select | RTC_DIV_RESET2, RTC_FREQ_SELECT);
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cmos_minutes = CMOS_READ(RTC_MINUTES);
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if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
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cmos_minutes = bcd2bin(cmos_minutes);
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/*
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* since we're only adjusting minutes and seconds,
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* don't interfere with hour overflow. This avoids
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* messing with unknown time zones but requires your
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* RTC not to be off by more than 15 minutes
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*/
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real_seconds = nowtime % 60;
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real_minutes = nowtime / 60;
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if (((abs(real_minutes - cmos_minutes) + 15) / 30) & 1)
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/* correct for half hour time zone */
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real_minutes += 30;
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real_minutes %= 60;
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if (abs(real_minutes - cmos_minutes) < 30) {
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if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
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real_seconds = bin2bcd(real_seconds);
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real_minutes = bin2bcd(real_minutes);
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}
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CMOS_WRITE(real_seconds, RTC_SECONDS);
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CMOS_WRITE(real_minutes, RTC_MINUTES);
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} else {
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printk(KERN_WARNING
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"set_rtc_mmss: can't update from %d to %d\n",
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cmos_minutes, real_minutes);
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retval = -1;
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}
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/* The following flags have to be released exactly in this order,
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* otherwise the DS12887 (popular MC146818A clone with integrated
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* battery and quartz) will not reset the oscillator and will not
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* update precisely 500 ms later. You won't find this mentioned in
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* the Dallas Semiconductor data sheets, but who believes data
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* sheets anyway ... -- Markus Kuhn
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*/
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CMOS_WRITE(save_control, RTC_CONTROL);
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CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
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spin_unlock(&rtc_lock);
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return retval;
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}
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int update_persistent_clock(struct timespec now)
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{
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return set_rtc_mmss(now.tv_sec);
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}
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/*
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* calibrate the TSC clock against the RTC
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*/
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void __init calibrate_clock(void)
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{
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unsigned char status;
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/* make sure the RTC is running and is set to operate in 24hr mode */
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status = RTSRC;
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RTCRB |= RTCRB_SET;
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RTCRB |= RTCRB_TM_24HR;
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RTCRB &= ~RTCRB_DM_BINARY;
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RTCRA |= RTCRA_DVR;
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RTCRA &= ~RTCRA_DVR;
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RTCRB &= ~RTCRB_SET;
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}
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