/* * arch/arm/mach-footbridge/include/mach/time.h * * Copyright (C) 1998 Russell King. * Copyright (C) 1998 Phil Blundell * * CATS has a real-time clock, though the evaluation board doesn't. * * Changelog: * 21-Mar-1998 RMK Created * 27-Aug-1998 PJB CATS support * 28-Dec-1998 APH Made leds optional * 20-Jan-1999 RMK Started merge of EBSA285, CATS and NetWinder * 16-Mar-1999 RMK More support for EBSA285-like machines with RTCs in */ #define RTC_PORT(x) (rtc_base+(x)) #define RTC_ALWAYS_BCD 0 #include <linux/timex.h> #include <linux/init.h> #include <linux/sched.h> #include <linux/mc146818rtc.h> #include <linux/bcd.h> #include <linux/io.h> #include <mach/hardware.h> #include <asm/mach/time.h> #include "common.h" static int rtc_base; static unsigned long __init get_isa_cmos_time(void) { unsigned int year, mon, day, hour, min, sec; // check to see if the RTC makes sense..... if ((CMOS_READ(RTC_VALID) & RTC_VRT) == 0) return mktime(1970, 1, 1, 0, 0, 0); do { sec = CMOS_READ(RTC_SECONDS); min = CMOS_READ(RTC_MINUTES); hour = CMOS_READ(RTC_HOURS); day = CMOS_READ(RTC_DAY_OF_MONTH); mon = CMOS_READ(RTC_MONTH); year = CMOS_READ(RTC_YEAR); } while (sec != CMOS_READ(RTC_SECONDS)); if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { sec = bcd2bin(sec); min = bcd2bin(min); hour = bcd2bin(hour); day = bcd2bin(day); mon = bcd2bin(mon); year = bcd2bin(year); } if ((year += 1900) < 1970) year += 100; return mktime(year, mon, day, hour, min, sec); } static int set_isa_cmos_time(void) { int retval = 0; int real_seconds, real_minutes, cmos_minutes; unsigned char save_control, save_freq_select; unsigned long nowtime = xtime.tv_sec; save_control = CMOS_READ(RTC_CONTROL); /* tell the clock it's being set */ CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL); save_freq_select = CMOS_READ(RTC_FREQ_SELECT); /* stop and reset prescaler */ CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT); cmos_minutes = CMOS_READ(RTC_MINUTES); if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) cmos_minutes = bcd2bin(cmos_minutes); /* * since we're only adjusting minutes and seconds, * don't interfere with hour overflow. This avoids * messing with unknown time zones but requires your * RTC not to be off by more than 15 minutes */ 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) { if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { real_seconds = bin2bcd(real_seconds); real_minutes = bin2bcd(real_minutes); } CMOS_WRITE(real_seconds,RTC_SECONDS); CMOS_WRITE(real_minutes,RTC_MINUTES); } else retval = -1; /* The following flags have to be released exactly in this order, * otherwise the DS12887 (popular MC146818A clone with integrated * battery and quartz) will not reset the oscillator and will not * update precisely 500 ms later. You won't find this mentioned in * the Dallas Semiconductor data sheets, but who believes data * sheets anyway ... -- Markus Kuhn */ CMOS_WRITE(save_control, RTC_CONTROL); CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT); return retval; } void __init isa_rtc_init(void) { if (machine_is_personal_server()) /* * Add-in 21285s shouldn't access the RTC */ rtc_base = 0; else rtc_base = 0x70; if (rtc_base) { int reg_d, reg_b; /* * Probe for the RTC. */ reg_d = CMOS_READ(RTC_REG_D); /* * make sure the divider is set */ CMOS_WRITE(RTC_REF_CLCK_32KHZ, RTC_REG_A); /* * Set control reg B * (24 hour mode, update enabled) */ reg_b = CMOS_READ(RTC_REG_B) & 0x7f; reg_b |= 2; CMOS_WRITE(reg_b, RTC_REG_B); if ((CMOS_READ(RTC_REG_A) & 0x7f) == RTC_REF_CLCK_32KHZ && CMOS_READ(RTC_REG_B) == reg_b) { struct timespec tv; /* * We have a RTC. Check the battery */ if ((reg_d & 0x80) == 0) printk(KERN_WARNING "RTC: *** warning: CMOS battery bad\n"); tv.tv_nsec = 0; tv.tv_sec = get_isa_cmos_time(); do_settimeofday(&tv); set_rtc = set_isa_cmos_time; } else rtc_base = 0; } }