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/Ethereal-msm8939-beta9/arch/mips/dec/time.c

https://bitbucket.org/MilosStamenkovic95/etherealos
C | 154 lines | 93 code | 24 blank | 37 comment | 17 complexity | 64d9c573c47a013d43767b34de2bbfe7 MD5 | raw file
  1/*
  2 *  Copyright (C) 1991, 1992, 1995  Linus Torvalds
  3 *  Copyright (C) 2000, 2003  Maciej W. Rozycki
  4 *
  5 * This file contains the time handling details for PC-style clocks as
  6 * found in some MIPS systems.
  7 *
  8 */
  9#include <linux/bcd.h>
 10#include <linux/init.h>
 11#include <linux/mc146818rtc.h>
 12#include <linux/param.h>
 13
 14#include <asm/cpu-features.h>
 15#include <asm/ds1287.h>
 16#include <asm/time.h>
 17#include <asm/dec/interrupts.h>
 18#include <asm/dec/ioasic.h>
 19#include <asm/dec/machtype.h>
 20
 21void read_persistent_clock(struct timespec *ts)
 22{
 23	unsigned int year, mon, day, hour, min, sec, real_year;
 24	unsigned long flags;
 25
 26	spin_lock_irqsave(&rtc_lock, flags);
 27
 28	do {
 29		sec = CMOS_READ(RTC_SECONDS);
 30		min = CMOS_READ(RTC_MINUTES);
 31		hour = CMOS_READ(RTC_HOURS);
 32		day = CMOS_READ(RTC_DAY_OF_MONTH);
 33		mon = CMOS_READ(RTC_MONTH);
 34		year = CMOS_READ(RTC_YEAR);
 35		/*
 36		 * The PROM will reset the year to either '72 or '73.
 37		 * Therefore we store the real year separately, in one
 38		 * of unused BBU RAM locations.
 39		 */
 40		real_year = CMOS_READ(RTC_DEC_YEAR);
 41	} while (sec != CMOS_READ(RTC_SECONDS));
 42
 43	spin_unlock_irqrestore(&rtc_lock, flags);
 44
 45	if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 46		sec = bcd2bin(sec);
 47		min = bcd2bin(min);
 48		hour = bcd2bin(hour);
 49		day = bcd2bin(day);
 50		mon = bcd2bin(mon);
 51		year = bcd2bin(year);
 52	}
 53
 54	year += real_year - 72 + 2000;
 55
 56	ts->tv_sec = mktime(year, mon, day, hour, min, sec);
 57	ts->tv_nsec = 0;
 58}
 59
 60/*
 61 * In order to set the CMOS clock precisely, rtc_mips_set_mmss has to
 62 * be called 500 ms after the second nowtime has started, because when
 63 * nowtime is written into the registers of the CMOS clock, it will
 64 * jump to the next second precisely 500 ms later.  Check the Dallas
 65 * DS1287 data sheet for details.
 66 */
 67int rtc_mips_set_mmss(unsigned long nowtime)
 68{
 69	int retval = 0;
 70	int real_seconds, real_minutes, cmos_minutes;
 71	unsigned char save_control, save_freq_select;
 72
 73	/* irq are locally disabled here */
 74	spin_lock(&rtc_lock);
 75	/* tell the clock it's being set */
 76	save_control = CMOS_READ(RTC_CONTROL);
 77	CMOS_WRITE((save_control | RTC_SET), RTC_CONTROL);
 78
 79	/* stop and reset prescaler */
 80	save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
 81	CMOS_WRITE((save_freq_select | RTC_DIV_RESET2), RTC_FREQ_SELECT);
 82
 83	cmos_minutes = CMOS_READ(RTC_MINUTES);
 84	if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
 85		cmos_minutes = bcd2bin(cmos_minutes);
 86
 87	/*
 88	 * since we're only adjusting minutes and seconds,
 89	 * don't interfere with hour overflow. This avoids
 90	 * messing with unknown time zones but requires your
 91	 * RTC not to be off by more than 15 minutes
 92	 */
 93	real_seconds = nowtime % 60;
 94	real_minutes = nowtime / 60;
 95	if (((abs(real_minutes - cmos_minutes) + 15) / 30) & 1)
 96		real_minutes += 30;	/* correct for half hour time zone */
 97	real_minutes %= 60;
 98
 99	if (abs(real_minutes - cmos_minutes) < 30) {
100		if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
101			real_seconds = bin2bcd(real_seconds);
102			real_minutes = bin2bcd(real_minutes);
103		}
104		CMOS_WRITE(real_seconds, RTC_SECONDS);
105		CMOS_WRITE(real_minutes, RTC_MINUTES);
106	} else {
107		printk_once(KERN_NOTICE
108		       "set_rtc_mmss: can't update from %d to %d\n",
109		       cmos_minutes, real_minutes);
110		retval = -1;
111	}
112
113	/* The following flags have to be released exactly in this order,
114	 * otherwise the DS1287 will not reset the oscillator and will not
115	 * update precisely 500 ms later.  You won't find this mentioned
116	 * in the Dallas Semiconductor data sheets, but who believes data
117	 * sheets anyway ...                           -- Markus Kuhn
118	 */
119	CMOS_WRITE(save_control, RTC_CONTROL);
120	CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
121	spin_unlock(&rtc_lock);
122
123	return retval;
124}
125
126void __init plat_time_init(void)
127{
128	u32 start, end;
129	int i = HZ / 10;
130
131	/* Set up the rate of periodic DS1287 interrupts. */
132	ds1287_set_base_clock(HZ);
133
134	if (cpu_has_counter) {
135		while (!ds1287_timer_state())
136			;
137
138		start = read_c0_count();
139
140		while (i--)
141			while (!ds1287_timer_state())
142				;
143
144		end = read_c0_count();
145
146		mips_hpt_frequency = (end - start) * 10;
147		printk(KERN_INFO "MIPS counter frequency %dHz\n",
148			mips_hpt_frequency);
149	} else if (IOASIC)
150		/* For pre-R4k systems we use the I/O ASIC's counter.  */
151		dec_ioasic_clocksource_init();
152
153	ds1287_clockevent_init(dec_interrupt[DEC_IRQ_RTC]);
154}