11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * linux/arch/mips/dec/time.c 31da177e4SLinus Torvalds * 41da177e4SLinus Torvalds * Copyright (C) 1991, 1992, 1995 Linus Torvalds 51da177e4SLinus Torvalds * Copyright (C) 2000, 2003 Maciej W. Rozycki 61da177e4SLinus Torvalds * 71da177e4SLinus Torvalds * This file contains the time handling details for PC-style clocks as 81da177e4SLinus Torvalds * found in some MIPS systems. 91da177e4SLinus Torvalds * 101da177e4SLinus Torvalds */ 111da177e4SLinus Torvalds #include <linux/bcd.h> 121da177e4SLinus Torvalds #include <linux/errno.h> 131da177e4SLinus Torvalds #include <linux/init.h> 141da177e4SLinus Torvalds #include <linux/interrupt.h> 151da177e4SLinus Torvalds #include <linux/kernel.h> 161da177e4SLinus Torvalds #include <linux/mc146818rtc.h> 171da177e4SLinus Torvalds #include <linux/mm.h> 181da177e4SLinus Torvalds #include <linux/module.h> 191da177e4SLinus Torvalds #include <linux/param.h> 201da177e4SLinus Torvalds #include <linux/sched.h> 211da177e4SLinus Torvalds #include <linux/string.h> 221da177e4SLinus Torvalds #include <linux/time.h> 231da177e4SLinus Torvalds #include <linux/types.h> 241da177e4SLinus Torvalds 251da177e4SLinus Torvalds #include <asm/bootinfo.h> 261da177e4SLinus Torvalds #include <asm/cpu.h> 271da177e4SLinus Torvalds #include <asm/div64.h> 281da177e4SLinus Torvalds #include <asm/io.h> 291da177e4SLinus Torvalds #include <asm/irq.h> 301da177e4SLinus Torvalds #include <asm/mipsregs.h> 311da177e4SLinus Torvalds #include <asm/sections.h> 321da177e4SLinus Torvalds #include <asm/time.h> 331da177e4SLinus Torvalds 341da177e4SLinus Torvalds #include <asm/dec/interrupts.h> 351da177e4SLinus Torvalds #include <asm/dec/ioasic.h> 361da177e4SLinus Torvalds #include <asm/dec/ioasic_addrs.h> 371da177e4SLinus Torvalds #include <asm/dec/machtype.h> 381da177e4SLinus Torvalds 391da177e4SLinus Torvalds 401da177e4SLinus Torvalds static unsigned long dec_rtc_get_time(void) 411da177e4SLinus Torvalds { 421da177e4SLinus Torvalds unsigned int year, mon, day, hour, min, sec, real_year; 431da177e4SLinus Torvalds int i; 441da177e4SLinus Torvalds 451da177e4SLinus Torvalds /* The Linux interpretation of the DS1287 clock register contents: 461da177e4SLinus Torvalds * When the Update-In-Progress (UIP) flag goes from 1 to 0, the 471da177e4SLinus Torvalds * RTC registers show the second which has precisely just started. 481da177e4SLinus Torvalds * Let's hope other operating systems interpret the RTC the same way. 491da177e4SLinus Torvalds */ 501da177e4SLinus Torvalds /* read RTC exactly on falling edge of update flag */ 511da177e4SLinus Torvalds for (i = 0; i < 1000000; i++) /* may take up to 1 second... */ 521da177e4SLinus Torvalds if (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP) 531da177e4SLinus Torvalds break; 541da177e4SLinus Torvalds for (i = 0; i < 1000000; i++) /* must try at least 2.228 ms */ 551da177e4SLinus Torvalds if (!(CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP)) 561da177e4SLinus Torvalds break; 571da177e4SLinus Torvalds /* Isn't this overkill? UIP above should guarantee consistency */ 581da177e4SLinus Torvalds do { 591da177e4SLinus Torvalds sec = CMOS_READ(RTC_SECONDS); 601da177e4SLinus Torvalds min = CMOS_READ(RTC_MINUTES); 611da177e4SLinus Torvalds hour = CMOS_READ(RTC_HOURS); 621da177e4SLinus Torvalds day = CMOS_READ(RTC_DAY_OF_MONTH); 631da177e4SLinus Torvalds mon = CMOS_READ(RTC_MONTH); 641da177e4SLinus Torvalds year = CMOS_READ(RTC_YEAR); 651da177e4SLinus Torvalds } while (sec != CMOS_READ(RTC_SECONDS)); 661da177e4SLinus Torvalds if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { 671da177e4SLinus Torvalds sec = BCD2BIN(sec); 681da177e4SLinus Torvalds min = BCD2BIN(min); 691da177e4SLinus Torvalds hour = BCD2BIN(hour); 701da177e4SLinus Torvalds day = BCD2BIN(day); 711da177e4SLinus Torvalds mon = BCD2BIN(mon); 721da177e4SLinus Torvalds year = BCD2BIN(year); 731da177e4SLinus Torvalds } 741da177e4SLinus Torvalds /* 751da177e4SLinus Torvalds * The PROM will reset the year to either '72 or '73. 761da177e4SLinus Torvalds * Therefore we store the real year separately, in one 771da177e4SLinus Torvalds * of unused BBU RAM locations. 781da177e4SLinus Torvalds */ 791da177e4SLinus Torvalds real_year = CMOS_READ(RTC_DEC_YEAR); 801da177e4SLinus Torvalds year += real_year - 72 + 2000; 811da177e4SLinus Torvalds 821da177e4SLinus Torvalds return mktime(year, mon, day, hour, min, sec); 831da177e4SLinus Torvalds } 841da177e4SLinus Torvalds 851da177e4SLinus Torvalds /* 861da177e4SLinus Torvalds * In order to set the CMOS clock precisely, dec_rtc_set_mmss has to 871da177e4SLinus Torvalds * be called 500 ms after the second nowtime has started, because when 881da177e4SLinus Torvalds * nowtime is written into the registers of the CMOS clock, it will 891da177e4SLinus Torvalds * jump to the next second precisely 500 ms later. Check the Dallas 901da177e4SLinus Torvalds * DS1287 data sheet for details. 911da177e4SLinus Torvalds */ 921da177e4SLinus Torvalds static int dec_rtc_set_mmss(unsigned long nowtime) 931da177e4SLinus Torvalds { 941da177e4SLinus Torvalds int retval = 0; 951da177e4SLinus Torvalds int real_seconds, real_minutes, cmos_minutes; 961da177e4SLinus Torvalds unsigned char save_control, save_freq_select; 971da177e4SLinus Torvalds 981da177e4SLinus Torvalds /* tell the clock it's being set */ 991da177e4SLinus Torvalds save_control = CMOS_READ(RTC_CONTROL); 1001da177e4SLinus Torvalds CMOS_WRITE((save_control | RTC_SET), RTC_CONTROL); 1011da177e4SLinus Torvalds 1021da177e4SLinus Torvalds /* stop and reset prescaler */ 1031da177e4SLinus Torvalds save_freq_select = CMOS_READ(RTC_FREQ_SELECT); 1041da177e4SLinus Torvalds CMOS_WRITE((save_freq_select | RTC_DIV_RESET2), RTC_FREQ_SELECT); 1051da177e4SLinus Torvalds 1061da177e4SLinus Torvalds cmos_minutes = CMOS_READ(RTC_MINUTES); 1071da177e4SLinus Torvalds if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) 1081da177e4SLinus Torvalds cmos_minutes = BCD2BIN(cmos_minutes); 1091da177e4SLinus Torvalds 1101da177e4SLinus Torvalds /* 1111da177e4SLinus Torvalds * since we're only adjusting minutes and seconds, 1121da177e4SLinus Torvalds * don't interfere with hour overflow. This avoids 1131da177e4SLinus Torvalds * messing with unknown time zones but requires your 1141da177e4SLinus Torvalds * RTC not to be off by more than 15 minutes 1151da177e4SLinus Torvalds */ 1161da177e4SLinus Torvalds real_seconds = nowtime % 60; 1171da177e4SLinus Torvalds real_minutes = nowtime / 60; 1181da177e4SLinus Torvalds if (((abs(real_minutes - cmos_minutes) + 15) / 30) & 1) 1191da177e4SLinus Torvalds real_minutes += 30; /* correct for half hour time zone */ 1201da177e4SLinus Torvalds real_minutes %= 60; 1211da177e4SLinus Torvalds 1221da177e4SLinus Torvalds if (abs(real_minutes - cmos_minutes) < 30) { 1231da177e4SLinus Torvalds if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { 1241da177e4SLinus Torvalds real_seconds = BIN2BCD(real_seconds); 1251da177e4SLinus Torvalds real_minutes = BIN2BCD(real_minutes); 1261da177e4SLinus Torvalds } 1271da177e4SLinus Torvalds CMOS_WRITE(real_seconds, RTC_SECONDS); 1281da177e4SLinus Torvalds CMOS_WRITE(real_minutes, RTC_MINUTES); 1291da177e4SLinus Torvalds } else { 1301da177e4SLinus Torvalds printk(KERN_WARNING 1311da177e4SLinus Torvalds "set_rtc_mmss: can't update from %d to %d\n", 1321da177e4SLinus Torvalds cmos_minutes, real_minutes); 1331da177e4SLinus Torvalds retval = -1; 1341da177e4SLinus Torvalds } 1351da177e4SLinus Torvalds 1361da177e4SLinus Torvalds /* The following flags have to be released exactly in this order, 1371da177e4SLinus Torvalds * otherwise the DS1287 will not reset the oscillator and will not 1381da177e4SLinus Torvalds * update precisely 500 ms later. You won't find this mentioned 1391da177e4SLinus Torvalds * in the Dallas Semiconductor data sheets, but who believes data 1401da177e4SLinus Torvalds * sheets anyway ... -- Markus Kuhn 1411da177e4SLinus Torvalds */ 1421da177e4SLinus Torvalds CMOS_WRITE(save_control, RTC_CONTROL); 1431da177e4SLinus Torvalds CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT); 1441da177e4SLinus Torvalds 1451da177e4SLinus Torvalds return retval; 1461da177e4SLinus Torvalds } 1471da177e4SLinus Torvalds 1481da177e4SLinus Torvalds 1491da177e4SLinus Torvalds static int dec_timer_state(void) 1501da177e4SLinus Torvalds { 1511da177e4SLinus Torvalds return (CMOS_READ(RTC_REG_C) & RTC_PF) != 0; 1521da177e4SLinus Torvalds } 1531da177e4SLinus Torvalds 1541da177e4SLinus Torvalds static void dec_timer_ack(void) 1551da177e4SLinus Torvalds { 1561da177e4SLinus Torvalds CMOS_READ(RTC_REG_C); /* Ack the RTC interrupt. */ 1571da177e4SLinus Torvalds } 1581da177e4SLinus Torvalds 1591da177e4SLinus Torvalds static unsigned int dec_ioasic_hpt_read(void) 1601da177e4SLinus Torvalds { 1611da177e4SLinus Torvalds /* 1621da177e4SLinus Torvalds * The free-running counter is 32-bit which is good for about 1631da177e4SLinus Torvalds * 2 minutes, 50 seconds at possible count rates of up to 25MHz. 1641da177e4SLinus Torvalds */ 1651da177e4SLinus Torvalds return ioasic_read(IO_REG_FCTR); 1661da177e4SLinus Torvalds } 1671da177e4SLinus Torvalds 1681da177e4SLinus Torvalds static void dec_ioasic_hpt_init(unsigned int count) 1691da177e4SLinus Torvalds { 1701da177e4SLinus Torvalds ioasic_write(IO_REG_FCTR, ioasic_read(IO_REG_FCTR) - count); 1711da177e4SLinus Torvalds } 1721da177e4SLinus Torvalds 1731da177e4SLinus Torvalds 1741da177e4SLinus Torvalds void __init dec_time_init(void) 1751da177e4SLinus Torvalds { 1761da177e4SLinus Torvalds rtc_get_time = dec_rtc_get_time; 1771da177e4SLinus Torvalds rtc_set_mmss = dec_rtc_set_mmss; 1781da177e4SLinus Torvalds 1791da177e4SLinus Torvalds mips_timer_state = dec_timer_state; 1801da177e4SLinus Torvalds mips_timer_ack = dec_timer_ack; 1811da177e4SLinus Torvalds 1821da177e4SLinus Torvalds if (!cpu_has_counter && IOASIC) { 1831da177e4SLinus Torvalds /* For pre-R4k systems we use the I/O ASIC's counter. */ 1841da177e4SLinus Torvalds mips_hpt_read = dec_ioasic_hpt_read; 1851da177e4SLinus Torvalds mips_hpt_init = dec_ioasic_hpt_init; 1861da177e4SLinus Torvalds } 1871da177e4SLinus Torvalds 1881da177e4SLinus Torvalds /* Set up the rate of periodic DS1287 interrupts. */ 1891da177e4SLinus Torvalds CMOS_WRITE(RTC_REF_CLCK_32KHZ | (16 - LOG_2_HZ), RTC_REG_A); 1901da177e4SLinus Torvalds } 1911da177e4SLinus Torvalds 1921da177e4SLinus Torvalds EXPORT_SYMBOL(do_settimeofday); 1931da177e4SLinus Torvalds 1941da177e4SLinus Torvalds void __init dec_timer_setup(struct irqaction *irq) 1951da177e4SLinus Torvalds { 1961da177e4SLinus Torvalds setup_irq(dec_interrupt[DEC_IRQ_RTC], irq); 1971da177e4SLinus Torvalds 1981da177e4SLinus Torvalds /* Enable periodic DS1287 interrupts. */ 1991da177e4SLinus Torvalds CMOS_WRITE(CMOS_READ(RTC_REG_B) | RTC_PIE, RTC_REG_B); 2001da177e4SLinus Torvalds } 201