arch/sh/boards/mach-sh03/rtc.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * linux/arch/sh/boards/sh03/rtc.c -- CTP/PCI-SH03 on-chip RTC support
   4  *
   5  *  Copyright (C) 2004  Saito.K & Jeanne(ksaito@interface.co.jp)
   6  *
   7  */
   8
   9 #include <linux/init.h>
  10 #include <linux/kernel.h>
  11 #include <linux/sched.h>
  12 #include <linux/time.h>
  13 #include <linux/bcd.h>
  14 #include <linux/rtc.h>
  15 #include <linux/spinlock.h>
  16 #include <asm/io.h>
  17 #include <asm/rtc.h>
  18
  19 #define RTC_BASE        0xb0000000
  20 #define RTC_SEC1        (RTC_BASE + 0)
  21 #define RTC_SEC10       (RTC_BASE + 1)
  22 #define RTC_MIN1        (RTC_BASE + 2)
  23 #define RTC_MIN10       (RTC_BASE + 3)
  24 #define RTC_HOU1        (RTC_BASE + 4)
  25 #define RTC_HOU10       (RTC_BASE + 5)
  26 #define RTC_WEE1        (RTC_BASE + 6)
  27 #define RTC_DAY1        (RTC_BASE + 7)
  28 #define RTC_DAY10       (RTC_BASE + 8)
  29 #define RTC_MON1        (RTC_BASE + 9)
  30 #define RTC_MON10       (RTC_BASE + 10)
  31 #define RTC_YEA1        (RTC_BASE + 11)
  32 #define RTC_YEA10       (RTC_BASE + 12)
  33 #define RTC_YEA100      (RTC_BASE + 13)
  34 #define RTC_YEA1000     (RTC_BASE + 14)
  35 #define RTC_CTL         (RTC_BASE + 15)
  36 #define RTC_BUSY        1
  37 #define RTC_STOP        2
  38
  39 static DEFINE_SPINLOCK(sh03_rtc_lock);
  40
  41 unsigned long get_cmos_time(void)
  42 {
  43         unsigned int year, mon, day, hour, min, sec;
  44
  45         spin_lock(&sh03_rtc_lock);
  46  again:
  47         do {
  48                 sec  = (__raw_readb(RTC_SEC1) & 0xf) + (__raw_readb(RTC_SEC10) & 0x7) * 10;
  49                 min  = (__raw_readb(RTC_MIN1) & 0xf) + (__raw_readb(RTC_MIN10) & 0xf) * 10;
  50                 hour = (__raw_readb(RTC_HOU1) & 0xf) + (__raw_readb(RTC_HOU10) & 0xf) * 10;
  51                 day  = (__raw_readb(RTC_DAY1) & 0xf) + (__raw_readb(RTC_DAY10) & 0xf) * 10;
  52                 mon  = (__raw_readb(RTC_MON1) & 0xf) + (__raw_readb(RTC_MON10) & 0xf) * 10;
  53                 year = (__raw_readb(RTC_YEA1) & 0xf) + (__raw_readb(RTC_YEA10) & 0xf) * 10
  54                      + (__raw_readb(RTC_YEA100 ) & 0xf) * 100
  55                      + (__raw_readb(RTC_YEA1000) & 0xf) * 1000;
  56         } while (sec != (__raw_readb(RTC_SEC1) & 0xf) + (__raw_readb(RTC_SEC10) & 0x7) * 10);
  57         if (year == 0 || mon < 1 || mon > 12 || day > 31 || day < 1 ||
  58             hour > 23 || min > 59 || sec > 59) {
  59                 printk(KERN_ERR
  60                        "SH-03 RTC: invalid value, resetting to 1 Jan 2000\n");
  61                 printk("year=%d, mon=%d, day=%d, hour=%d, min=%d, sec=%d\n",
  62                        year, mon, day, hour, min, sec);
  63
  64                 __raw_writeb(0, RTC_SEC1); __raw_writeb(0, RTC_SEC10);
  65                 __raw_writeb(0, RTC_MIN1); __raw_writeb(0, RTC_MIN10);
  66                 __raw_writeb(0, RTC_HOU1); __raw_writeb(0, RTC_HOU10);
  67                 __raw_writeb(6, RTC_WEE1);
  68                 __raw_writeb(1, RTC_DAY1); __raw_writeb(0, RTC_DAY10);
  69                 __raw_writeb(1, RTC_MON1); __raw_writeb(0, RTC_MON10);
  70                 __raw_writeb(0, RTC_YEA1); __raw_writeb(0, RTC_YEA10);
  71                 __raw_writeb(0, RTC_YEA100);
  72                 __raw_writeb(2, RTC_YEA1000);
  73                 __raw_writeb(0, RTC_CTL);
  74                 goto again;
  75         }
  76
  77         spin_unlock(&sh03_rtc_lock);
  78         return mktime(year, mon, day, hour, min, sec);
  79 }
  80
  81 void sh03_rtc_gettimeofday(struct timespec *tv)
  82 {
  83
  84         tv->tv_sec = get_cmos_time();
  85         tv->tv_nsec = 0;
  86 }
  87
  88 static int set_rtc_mmss(unsigned long nowtime)
  89 {
  90         int retval = 0;
  91         int real_seconds, real_minutes, cmos_minutes;
  92         int i;
  93
  94         /* gets recalled with irq locally disabled */
  95         spin_lock(&sh03_rtc_lock);
  96         for (i = 0 ; i < 1000000 ; i++) /* may take up to 1 second... */
  97                 if (!(__raw_readb(RTC_CTL) & RTC_BUSY))
  98                         break;
  99         cmos_minutes = (__raw_readb(RTC_MIN1) & 0xf) + (__raw_readb(RTC_MIN10) & 0xf) * 10;
 100         real_seconds = nowtime % 60;
 101         real_minutes = nowtime / 60;
 102         if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)
 103                 real_minutes += 30;             /* correct for half hour time zone */
 104         real_minutes %= 60;
 105
 106         if (abs(real_minutes - cmos_minutes) < 30) {
 107                 __raw_writeb(real_seconds % 10, RTC_SEC1);
 108                 __raw_writeb(real_seconds / 10, RTC_SEC10);
 109                 __raw_writeb(real_minutes % 10, RTC_MIN1);
 110                 __raw_writeb(real_minutes / 10, RTC_MIN10);
 111         } else {
 112                 printk_once(KERN_NOTICE
 113                        "set_rtc_mmss: can't update from %d to %d\n",
 114                        cmos_minutes, real_minutes);
 115                 retval = -1;
 116         }
 117         spin_unlock(&sh03_rtc_lock);
 118
 119         return retval;
 120 }
 121
 122 int sh03_rtc_settimeofday(const time_t secs)
 123 {
 124         unsigned long nowtime = secs;
 125
 126         return set_rtc_mmss(nowtime);
 127 }
 128
 129 void sh03_time_init(void)
 130 {
 131         rtc_sh_get_time = sh03_rtc_gettimeofday;
 132         rtc_sh_set_time = sh03_rtc_settimeofday;
 133 }