/* * linux/arch/mips/dec/time.c * * Copyright (C) 1991, 1992, 1995 Linus Torvalds * Copyright (C) 2000, 2003 Maciej W. Rozycki * * This file contains the time handling details for PC-style clocks as * found in some MIPS systems. * */ #include <linux/bcd.h> #include <linux/errno.h> #include <linux/init.h> #include <linux/interrupt.h> #include <linux/kernel.h> #include <linux/mc146818rtc.h> #include <linux/mm.h> #include <linux/module.h> #include <linux/param.h> #include <linux/sched.h> #include <linux/string.h> #include <linux/time.h> #include <linux/types.h> #include <asm/bootinfo.h> #include <asm/cpu.h> #include <asm/io.h> #include <asm/irq.h> #include <asm/mipsregs.h> #include <asm/sections.h> #include <asm/time.h> #include <asm/dec/interrupts.h> #include <asm/dec/ioasic.h> #include <asm/dec/ioasic_addrs.h> #include <asm/dec/machtype.h> unsigned long read_persistent_clock(void) { unsigned int year, mon, day, hour, min, sec, real_year; unsigned long flags; spin_lock_irqsave(&rtc_lock, flags); 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); /* * The PROM will reset the year to either '72 or '73. * Therefore we store the real year separately, in one * of unused BBU RAM locations. */ real_year = CMOS_READ(RTC_DEC_YEAR); } while (sec != CMOS_READ(RTC_SECONDS)); spin_unlock_irqrestore(&rtc_lock, flags); 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); } year += real_year - 72 + 2000; return mktime(year, mon, day, hour, min, sec); } /* * In order to set the CMOS clock precisely, rtc_mips_set_mmss has to * be called 500 ms after the second nowtime has started, because when * nowtime is written into the registers of the CMOS clock, it will * jump to the next second precisely 500 ms later. Check the Dallas * DS1287 data sheet for details. */ int rtc_mips_set_mmss(unsigned long nowtime) { int retval = 0; int real_seconds, real_minutes, cmos_minutes; unsigned char save_control, save_freq_select; /* irq are locally disabled here */ spin_lock(&rtc_lock); /* tell the clock it's being set */ save_control = CMOS_READ(RTC_CONTROL); CMOS_WRITE((save_control | RTC_SET), RTC_CONTROL); /* stop and reset prescaler */ save_freq_select = CMOS_READ(RTC_FREQ_SELECT); 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 { printk(KERN_WARNING "set_rtc_mmss: can't update from %d to %d\n", cmos_minutes, real_minutes); retval = -1; } /* The following flags have to be released exactly in this order, * otherwise the DS1287 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); spin_unlock(&rtc_lock); return retval; } static int dec_timer_state(void) { return (CMOS_READ(RTC_REG_C) & RTC_PF) != 0; } static void dec_timer_ack(void) { CMOS_READ(RTC_REG_C); /* Ack the RTC interrupt. */ } static cycle_t dec_ioasic_hpt_read(void) { /* * The free-running counter is 32-bit which is good for about * 2 minutes, 50 seconds at possible count rates of up to 25MHz. */ return ioasic_read(IO_REG_FCTR); } void __init plat_time_init(void) { mips_timer_ack = dec_timer_ack; if (!cpu_has_counter && IOASIC) /* For pre-R4k systems we use the I/O ASIC's counter. */ clocksource_mips.read = dec_ioasic_hpt_read; /* Set up the rate of periodic DS1287 interrupts. */ CMOS_WRITE(RTC_REF_CLCK_32KHZ | (16 - __ffs(HZ)), RTC_REG_A); } void __init plat_timer_setup(struct irqaction *irq) { setup_irq(dec_interrupt[DEC_IRQ_RTC], irq); /* Enable periodic DS1287 interrupts. */ CMOS_WRITE(CMOS_READ(RTC_REG_B) | RTC_PIE, RTC_REG_B); }