linux/arch/sh/boards/mach-sh03/rtc.c
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   1/*
   2 * linux/arch/sh/boards/sh03/rtc.c -- CTP/PCI-SH03 on-chip RTC support
   3 *
   4 *  Copyright (C) 2004  Saito.K & Jeanne(ksaito@interface.co.jp)
   5 *
   6 */
   7
   8#include <linux/init.h>
   9#include <linux/kernel.h>
  10#include <linux/sched.h>
  11#include <linux/time.h>
  12#include <linux/bcd.h>
  13#include <linux/rtc.h>
  14#include <linux/spinlock.h>
  15#include <asm/io.h>
  16#include <asm/rtc.h>
  17
  18#define RTC_BASE        0xb0000000
  19#define RTC_SEC1        (RTC_BASE + 0)
  20#define RTC_SEC10       (RTC_BASE + 1)
  21#define RTC_MIN1        (RTC_BASE + 2)
  22#define RTC_MIN10       (RTC_BASE + 3)
  23#define RTC_HOU1        (RTC_BASE + 4)
  24#define RTC_HOU10       (RTC_BASE + 5)
  25#define RTC_WEE1        (RTC_BASE + 6)
  26#define RTC_DAY1        (RTC_BASE + 7)
  27#define RTC_DAY10       (RTC_BASE + 8)
  28#define RTC_MON1        (RTC_BASE + 9)
  29#define RTC_MON10       (RTC_BASE + 10)
  30#define RTC_YEA1        (RTC_BASE + 11)
  31#define RTC_YEA10       (RTC_BASE + 12)
  32#define RTC_YEA100      (RTC_BASE + 13)
  33#define RTC_YEA1000     (RTC_BASE + 14)
  34#define RTC_CTL         (RTC_BASE + 15)
  35#define RTC_BUSY        1
  36#define RTC_STOP        2
  37
  38static DEFINE_SPINLOCK(sh03_rtc_lock);
  39
  40unsigned long get_cmos_time(void)
  41{
  42        unsigned int year, mon, day, hour, min, sec;
  43
  44        spin_lock(&sh03_rtc_lock);
  45 again:
  46        do {
  47                sec  = (__raw_readb(RTC_SEC1) & 0xf) + (__raw_readb(RTC_SEC10) & 0x7) * 10;
  48                min  = (__raw_readb(RTC_MIN1) & 0xf) + (__raw_readb(RTC_MIN10) & 0xf) * 10;
  49                hour = (__raw_readb(RTC_HOU1) & 0xf) + (__raw_readb(RTC_HOU10) & 0xf) * 10;
  50                day  = (__raw_readb(RTC_DAY1) & 0xf) + (__raw_readb(RTC_DAY10) & 0xf) * 10;
  51                mon  = (__raw_readb(RTC_MON1) & 0xf) + (__raw_readb(RTC_MON10) & 0xf) * 10;
  52                year = (__raw_readb(RTC_YEA1) & 0xf) + (__raw_readb(RTC_YEA10) & 0xf) * 10
  53                     + (__raw_readb(RTC_YEA100 ) & 0xf) * 100
  54                     + (__raw_readb(RTC_YEA1000) & 0xf) * 1000;
  55        } while (sec != (__raw_readb(RTC_SEC1) & 0xf) + (__raw_readb(RTC_SEC10) & 0x7) * 10);
  56        if (year == 0 || mon < 1 || mon > 12 || day > 31 || day < 1 ||
  57            hour > 23 || min > 59 || sec > 59) {
  58                printk(KERN_ERR
  59                       "SH-03 RTC: invalid value, resetting to 1 Jan 2000\n");
  60                printk("year=%d, mon=%d, day=%d, hour=%d, min=%d, sec=%d\n",
  61                       year, mon, day, hour, min, sec);
  62
  63                __raw_writeb(0, RTC_SEC1); __raw_writeb(0, RTC_SEC10);
  64                __raw_writeb(0, RTC_MIN1); __raw_writeb(0, RTC_MIN10);
  65                __raw_writeb(0, RTC_HOU1); __raw_writeb(0, RTC_HOU10);
  66                __raw_writeb(6, RTC_WEE1);
  67                __raw_writeb(1, RTC_DAY1); __raw_writeb(0, RTC_DAY10);
  68                __raw_writeb(1, RTC_MON1); __raw_writeb(0, RTC_MON10);
  69                __raw_writeb(0, RTC_YEA1); __raw_writeb(0, RTC_YEA10);
  70                __raw_writeb(0, RTC_YEA100);
  71                __raw_writeb(2, RTC_YEA1000);
  72                __raw_writeb(0, RTC_CTL);
  73                goto again;
  74        }
  75
  76        spin_unlock(&sh03_rtc_lock);
  77        return mktime(year, mon, day, hour, min, sec);
  78}
  79
  80void sh03_rtc_gettimeofday(struct timespec *tv)
  81{
  82
  83        tv->tv_sec = get_cmos_time();
  84        tv->tv_nsec = 0;
  85}
  86
  87static int set_rtc_mmss(unsigned long nowtime)
  88{
  89        int retval = 0;
  90        int real_seconds, real_minutes, cmos_minutes;
  91        int i;
  92
  93        /* gets recalled with irq locally disabled */
  94        spin_lock(&sh03_rtc_lock);
  95        for (i = 0 ; i < 1000000 ; i++) /* may take up to 1 second... */
  96                if (!(__raw_readb(RTC_CTL) & RTC_BUSY))
  97                        break;
  98        cmos_minutes = (__raw_readb(RTC_MIN1) & 0xf) + (__raw_readb(RTC_MIN10) & 0xf) * 10;
  99        real_seconds = nowtime % 60;
 100        real_minutes = nowtime / 60;
 101        if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)
 102                real_minutes += 30;             /* correct for half hour time zone */
 103        real_minutes %= 60;
 104
 105        if (abs(real_minutes - cmos_minutes) < 30) {
 106                __raw_writeb(real_seconds % 10, RTC_SEC1);
 107                __raw_writeb(real_seconds / 10, RTC_SEC10);
 108                __raw_writeb(real_minutes % 10, RTC_MIN1);
 109                __raw_writeb(real_minutes / 10, RTC_MIN10);
 110        } else {
 111                printk_once(KERN_NOTICE
 112                       "set_rtc_mmss: can't update from %d to %d\n",
 113                       cmos_minutes, real_minutes);
 114                retval = -1;
 115        }
 116        spin_unlock(&sh03_rtc_lock);
 117
 118        return retval;
 119}
 120
 121int sh03_rtc_settimeofday(const time_t secs)
 122{
 123        unsigned long nowtime = secs;
 124
 125        return set_rtc_mmss(nowtime);
 126}
 127
 128void sh03_time_init(void)
 129{
 130        rtc_sh_get_time = sh03_rtc_gettimeofday;
 131        rtc_sh_set_time = sh03_rtc_settimeofday;
 132}
 133