rtc.c

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/*
 * linux/arch/sh/boards/sh03/rtc.c -- CTP/PCI-SH03 on-chip RTC support
 *
 *  Copyright (C) 2004  Saito.K & Jeanne([email protected])
 *
 */

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/time.h>
#include <linux/bcd.h>
#include <linux/rtc.h>
#include <linux/spinlock.h>
#include <asm/io.h>
#include <asm/rtc.h>

#define RTC_BASE    0xb0000000
#define RTC_SEC1    (RTC_BASE + 0)
#define RTC_SEC10   (RTC_BASE + 1)
#define RTC_MIN1    (RTC_BASE + 2)
#define RTC_MIN10   (RTC_BASE + 3)
#define RTC_HOU1    (RTC_BASE + 4)
#define RTC_HOU10   (RTC_BASE + 5)
#define RTC_WEE1    (RTC_BASE + 6)
#define RTC_DAY1    (RTC_BASE + 7)
#define RTC_DAY10   (RTC_BASE + 8)
#define RTC_MON1    (RTC_BASE + 9)
#define RTC_MON10   (RTC_BASE + 10)
#define RTC_YEA1    (RTC_BASE + 11)
#define RTC_YEA10   (RTC_BASE + 12)
#define RTC_YEA100  (RTC_BASE + 13)
#define RTC_YEA1000 (RTC_BASE + 14)
#define RTC_CTL     (RTC_BASE + 15)
#define RTC_BUSY    1
#define RTC_STOP    2

static DEFINE_SPINLOCK(sh03_rtc_lock);

unsigned long get_cmos_time(void)
{
    unsigned int year, mon, day, hour, min, sec;

    spin_lock(&sh03_rtc_lock);
 again:
    do {
        sec  = (__raw_readb(RTC_SEC1) & 0xf) + (__raw_readb(RTC_SEC10) & 0x7) * 10;
        min  = (__raw_readb(RTC_MIN1) & 0xf) + (__raw_readb(RTC_MIN10) & 0xf) * 10;
        hour = (__raw_readb(RTC_HOU1) & 0xf) + (__raw_readb(RTC_HOU10) & 0xf) * 10;
        day  = (__raw_readb(RTC_DAY1) & 0xf) + (__raw_readb(RTC_DAY10) & 0xf) * 10;
        mon  = (__raw_readb(RTC_MON1) & 0xf) + (__raw_readb(RTC_MON10) & 0xf) * 10;
        year = (__raw_readb(RTC_YEA1) & 0xf) + (__raw_readb(RTC_YEA10) & 0xf) * 10
             + (__raw_readb(RTC_YEA100 ) & 0xf) * 100
             + (__raw_readb(RTC_YEA1000) & 0xf) * 1000;
    } while (sec != (__raw_readb(RTC_SEC1) & 0xf) + (__raw_readb(RTC_SEC10) & 0x7) * 10);
    if (year == 0 || mon < 1 || mon > 12 || day > 31 || day < 1 ||
        hour > 23 || min > 59 || sec > 59) {
        printk(KERN_ERR
               "SH-03 RTC: invalid value, resetting to 1 Jan 2000\n");
        printk("year=%d, mon=%d, day=%d, hour=%d, min=%d, sec=%d\n",
               year, mon, day, hour, min, sec);

        __raw_writeb(0, RTC_SEC1); __raw_writeb(0, RTC_SEC10);
        __raw_writeb(0, RTC_MIN1); __raw_writeb(0, RTC_MIN10);
        __raw_writeb(0, RTC_HOU1); __raw_writeb(0, RTC_HOU10);
        __raw_writeb(6, RTC_WEE1);
        __raw_writeb(1, RTC_DAY1); __raw_writeb(0, RTC_DAY10);
        __raw_writeb(1, RTC_MON1); __raw_writeb(0, RTC_MON10);
        __raw_writeb(0, RTC_YEA1); __raw_writeb(0, RTC_YEA10);
        __raw_writeb(0, RTC_YEA100);
        __raw_writeb(2, RTC_YEA1000);
        __raw_writeb(0, RTC_CTL);
        goto again;
    }

    spin_unlock(&sh03_rtc_lock);
    return mktime(year, mon, day, hour, min, sec);
}

void sh03_rtc_gettimeofday(struct timespec *tv)
{

    tv->tv_sec = get_cmos_time();
    tv->tv_nsec = 0;
}

static int set_rtc_mmss(unsigned long nowtime)
{
    int retval = 0;
    int real_seconds, real_minutes, cmos_minutes;
    int i;

    /* gets recalled with irq locally disabled */
    spin_lock(&sh03_rtc_lock);
    for (i = 0 ; i < 1000000 ; i++) /* may take up to 1 second... */
        if (!(__raw_readb(RTC_CTL) & RTC_BUSY))
            break;
    cmos_minutes = (__raw_readb(RTC_MIN1) & 0xf) + (__raw_readb(RTC_MIN10) & 0xf) * 10;
    real_seconds = nowtime % 60;
    real_minutes = nowtime / 60;
    if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)
        real_minutes += 30;     /* correct for half hour time zone */
    real_minutes %= 60;

    if (abs(real_minutes - cmos_minutes) < 30) {
        __raw_writeb(real_seconds % 10, RTC_SEC1);
        __raw_writeb(real_seconds / 10, RTC_SEC10);
        __raw_writeb(real_minutes % 10, RTC_MIN1);
        __raw_writeb(real_minutes / 10, RTC_MIN10);
    } else {
        printk_once(KERN_NOTICE
               "set_rtc_mmss: can't update from %d to %d\n",
               cmos_minutes, real_minutes);
        retval = -1;
    }
    spin_unlock(&sh03_rtc_lock);

    return retval;
}

int sh03_rtc_settimeofday(const time_t secs)
{
    unsigned long nowtime = secs;

    return set_rtc_mmss(nowtime);
}

void sh03_time_init(void)
{
    rtc_sh_get_time = sh03_rtc_gettimeofday;
    rtc_sh_set_time = sh03_rtc_settimeofday;
}