1/* 2 * linux/include/asm-arm/arch-ebsa285/time.h 3 * 4 * Copyright (C) 1998 Russell King. 5 * Copyright (C) 1998 Phil Blundell 6 * 7 * CATS has a real-time clock, though the evaluation board doesn't. 8 * 9 * Changelog: 10 * 21-Mar-1998 RMK Created 11 * 27-Aug-1998 PJB CATS support 12 * 28-Dec-1998 APH Made leds optional 13 * 20-Jan-1999 RMK Started merge of EBSA285, CATS and NetWinder 14 * 16-Mar-1999 RMK More support for EBSA285-like machines with RTCs in 15 */ 16 17#define RTC_PORT(x) (rtc_base+(x)) 18#define RTC_ALWAYS_BCD 0 19 20#include <linux/timex.h> 21#include <linux/init.h> 22#include <linux/sched.h> 23#include <linux/mc146818rtc.h> 24#include <linux/bcd.h> 25 26#include <asm/hardware.h> 27#include <asm/io.h> 28 29#include <asm/mach/time.h> 30#include "common.h" 31 32static int rtc_base; 33 34static unsigned long __init get_isa_cmos_time(void) 35{ 36 unsigned int year, mon, day, hour, min, sec; 37 38 // check to see if the RTC makes sense..... 39 if ((CMOS_READ(RTC_VALID) & RTC_VRT) == 0) 40 return mktime(1970, 1, 1, 0, 0, 0); 41 42 do { 43 sec = CMOS_READ(RTC_SECONDS); 44 min = CMOS_READ(RTC_MINUTES); 45 hour = CMOS_READ(RTC_HOURS); 46 day = CMOS_READ(RTC_DAY_OF_MONTH); 47 mon = CMOS_READ(RTC_MONTH); 48 year = CMOS_READ(RTC_YEAR); 49 } while (sec != CMOS_READ(RTC_SECONDS)); 50 51 if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { 52 BCD_TO_BIN(sec); 53 BCD_TO_BIN(min); 54 BCD_TO_BIN(hour); 55 BCD_TO_BIN(day); 56 BCD_TO_BIN(mon); 57 BCD_TO_BIN(year); 58 } 59 if ((year += 1900) < 1970) 60 year += 100; 61 return mktime(year, mon, day, hour, min, sec); 62} 63 64static int set_isa_cmos_time(void) 65{ 66 int retval = 0; 67 int real_seconds, real_minutes, cmos_minutes; 68 unsigned char save_control, save_freq_select; 69 unsigned long nowtime = xtime.tv_sec; 70 71 save_control = CMOS_READ(RTC_CONTROL); /* tell the clock it's being set */ 72 CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL); 73 74 save_freq_select = CMOS_READ(RTC_FREQ_SELECT); /* stop and reset prescaler */ 75 CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT); 76 77 cmos_minutes = CMOS_READ(RTC_MINUTES); 78 if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) 79 BCD_TO_BIN(cmos_minutes); 80 81 /* 82 * since we're only adjusting minutes and seconds, 83 * don't interfere with hour overflow. This avoids 84 * messing with unknown time zones but requires your 85 * RTC not to be off by more than 15 minutes 86 */ 87 real_seconds = nowtime % 60; 88 real_minutes = nowtime / 60; 89 if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1) 90 real_minutes += 30; /* correct for half hour time zone */ 91 real_minutes %= 60; 92 93 if (abs(real_minutes - cmos_minutes) < 30) { 94 if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { 95 BIN_TO_BCD(real_seconds); 96 BIN_TO_BCD(real_minutes); 97 } 98 CMOS_WRITE(real_seconds,RTC_SECONDS); 99 CMOS_WRITE(real_minutes,RTC_MINUTES); 100 } else 101 retval = -1; 102 103 /* The following flags have to be released exactly in this order, 104 * otherwise the DS12887 (popular MC146818A clone with integrated 105 * battery and quartz) will not reset the oscillator and will not 106 * update precisely 500 ms later. You won't find this mentioned in 107 * the Dallas Semiconductor data sheets, but who believes data 108 * sheets anyway ... -- Markus Kuhn 109 */ 110 CMOS_WRITE(save_control, RTC_CONTROL); 111 CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT); 112 113 return retval; 114} 115 116void __init isa_rtc_init(void) 117{ 118 if (machine_is_co285() || 119 machine_is_personal_server()) 120 /* 121 * Add-in 21285s shouldn't access the RTC 122 */ 123 rtc_base = 0; 124 else 125 rtc_base = 0x70; 126 127 if (rtc_base) { 128 int reg_d, reg_b; 129 130 /* 131 * Probe for the RTC. 132 */ 133 reg_d = CMOS_READ(RTC_REG_D); 134 135 /* 136 * make sure the divider is set 137 */ 138 CMOS_WRITE(RTC_REF_CLCK_32KHZ, RTC_REG_A); 139 140 /* 141 * Set control reg B 142 * (24 hour mode, update enabled) 143 */ 144 reg_b = CMOS_READ(RTC_REG_B) & 0x7f; 145 reg_b |= 2; 146 CMOS_WRITE(reg_b, RTC_REG_B); 147 148 if ((CMOS_READ(RTC_REG_A) & 0x7f) == RTC_REF_CLCK_32KHZ && 149 CMOS_READ(RTC_REG_B) == reg_b) { 150 struct timespec tv; 151 152 /* 153 * We have a RTC. Check the battery 154 */ 155 if ((reg_d & 0x80) == 0) 156 printk(KERN_WARNING "RTC: *** warning: CMOS battery bad\n"); 157 158 tv.tv_nsec = 0; 159 tv.tv_sec = get_isa_cmos_time(); 160 do_settimeofday(&tv); 161 set_rtc = set_isa_cmos_time; 162 } else 163 rtc_base = 0; 164 } 165} 166