11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * linux/arch/alpha/kernel/time.c 31da177e4SLinus Torvalds * 41da177e4SLinus Torvalds * Copyright (C) 1991, 1992, 1995, 1999, 2000 Linus Torvalds 51da177e4SLinus Torvalds * 61da177e4SLinus Torvalds * This file contains the PC-specific time handling details: 71da177e4SLinus Torvalds * reading the RTC at bootup, etc.. 81da177e4SLinus Torvalds * 1994-07-02 Alan Modra 91da177e4SLinus Torvalds * fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime 101da177e4SLinus Torvalds * 1995-03-26 Markus Kuhn 111da177e4SLinus Torvalds * fixed 500 ms bug at call to set_rtc_mmss, fixed DS12887 121da177e4SLinus Torvalds * precision CMOS clock update 131da177e4SLinus Torvalds * 1997-09-10 Updated NTP code according to technical memorandum Jan '96 141da177e4SLinus Torvalds * "A Kernel Model for Precision Timekeeping" by Dave Mills 151da177e4SLinus Torvalds * 1997-01-09 Adrian Sun 161da177e4SLinus Torvalds * use interval timer if CONFIG_RTC=y 171da177e4SLinus Torvalds * 1997-10-29 John Bowman (bowman@math.ualberta.ca) 181da177e4SLinus Torvalds * fixed tick loss calculation in timer_interrupt 191da177e4SLinus Torvalds * (round system clock to nearest tick instead of truncating) 201da177e4SLinus Torvalds * fixed algorithm in time_init for getting time from CMOS clock 211da177e4SLinus Torvalds * 1999-04-16 Thorsten Kranzkowski (dl8bcu@gmx.net) 221da177e4SLinus Torvalds * fixed algorithm in do_gettimeofday() for calculating the precise time 231da177e4SLinus Torvalds * from processor cycle counter (now taking lost_ticks into account) 241da177e4SLinus Torvalds * 2000-08-13 Jan-Benedict Glaw <jbglaw@lug-owl.de> 251da177e4SLinus Torvalds * Fixed time_init to be aware of epoches != 1900. This prevents 261da177e4SLinus Torvalds * booting up in 2048 for me;) Code is stolen from rtc.c. 271da177e4SLinus Torvalds * 2003-06-03 R. Scott Bailey <scott.bailey@eds.com> 281da177e4SLinus Torvalds * Tighten sanity in time_init from 1% (10,000 PPM) to 250 PPM 291da177e4SLinus Torvalds */ 301da177e4SLinus Torvalds #include <linux/errno.h> 311da177e4SLinus Torvalds #include <linux/module.h> 321da177e4SLinus Torvalds #include <linux/sched.h> 331da177e4SLinus Torvalds #include <linux/kernel.h> 341da177e4SLinus Torvalds #include <linux/param.h> 351da177e4SLinus Torvalds #include <linux/string.h> 361da177e4SLinus Torvalds #include <linux/mm.h> 371da177e4SLinus Torvalds #include <linux/delay.h> 381da177e4SLinus Torvalds #include <linux/ioport.h> 391da177e4SLinus Torvalds #include <linux/irq.h> 401da177e4SLinus Torvalds #include <linux/interrupt.h> 411da177e4SLinus Torvalds #include <linux/init.h> 421da177e4SLinus Torvalds #include <linux/bcd.h> 431da177e4SLinus Torvalds #include <linux/profile.h> 441da177e4SLinus Torvalds 451da177e4SLinus Torvalds #include <asm/uaccess.h> 461da177e4SLinus Torvalds #include <asm/io.h> 471da177e4SLinus Torvalds #include <asm/hwrpb.h> 481da177e4SLinus Torvalds #include <asm/8253pit.h> 495f7dc5d7SIvan Kokshaysky #include <asm/rtc.h> 501da177e4SLinus Torvalds 511da177e4SLinus Torvalds #include <linux/mc146818rtc.h> 521da177e4SLinus Torvalds #include <linux/time.h> 531da177e4SLinus Torvalds #include <linux/timex.h> 549ce34c8fSJohn Stultz #include <linux/clocksource.h> 551da177e4SLinus Torvalds 561da177e4SLinus Torvalds #include "proto.h" 571da177e4SLinus Torvalds #include "irq_impl.h" 581da177e4SLinus Torvalds 591da177e4SLinus Torvalds static int set_rtc_mmss(unsigned long); 601da177e4SLinus Torvalds 611da177e4SLinus Torvalds DEFINE_SPINLOCK(rtc_lock); 62cff52dafSAl Viro EXPORT_SYMBOL(rtc_lock); 631da177e4SLinus Torvalds 641da177e4SLinus Torvalds #define TICK_SIZE (tick_nsec / 1000) 651da177e4SLinus Torvalds 661da177e4SLinus Torvalds /* 671da177e4SLinus Torvalds * Shift amount by which scaled_ticks_per_cycle is scaled. Shifting 681da177e4SLinus Torvalds * by 48 gives us 16 bits for HZ while keeping the accuracy good even 691da177e4SLinus Torvalds * for large CPU clock rates. 701da177e4SLinus Torvalds */ 711da177e4SLinus Torvalds #define FIX_SHIFT 48 721da177e4SLinus Torvalds 731da177e4SLinus Torvalds /* lump static variables together for more efficient access: */ 741da177e4SLinus Torvalds static struct { 751da177e4SLinus Torvalds /* cycle counter last time it got invoked */ 761da177e4SLinus Torvalds __u32 last_time; 771da177e4SLinus Torvalds /* ticks/cycle * 2^48 */ 781da177e4SLinus Torvalds unsigned long scaled_ticks_per_cycle; 791da177e4SLinus Torvalds /* partial unused tick */ 801da177e4SLinus Torvalds unsigned long partial_tick; 811da177e4SLinus Torvalds } state; 821da177e4SLinus Torvalds 831da177e4SLinus Torvalds unsigned long est_cycle_freq; 841da177e4SLinus Torvalds 851da177e4SLinus Torvalds 861da177e4SLinus Torvalds static inline __u32 rpcc(void) 871da177e4SLinus Torvalds { 881da177e4SLinus Torvalds __u32 result; 891da177e4SLinus Torvalds asm volatile ("rpcc %0" : "=r"(result)); 901da177e4SLinus Torvalds return result; 911da177e4SLinus Torvalds } 921da177e4SLinus Torvalds 931e871be1SJohn Stultz int update_persistent_clock(struct timespec now) 941e871be1SJohn Stultz { 951e871be1SJohn Stultz return set_rtc_mmss(now.tv_sec); 961e871be1SJohn Stultz } 971e871be1SJohn Stultz 981e871be1SJohn Stultz void read_persistent_clock(struct timespec *ts) 991e871be1SJohn Stultz { 1001e871be1SJohn Stultz unsigned int year, mon, day, hour, min, sec, epoch; 1011e871be1SJohn Stultz 1021e871be1SJohn Stultz sec = CMOS_READ(RTC_SECONDS); 1031e871be1SJohn Stultz min = CMOS_READ(RTC_MINUTES); 1041e871be1SJohn Stultz hour = CMOS_READ(RTC_HOURS); 1051e871be1SJohn Stultz day = CMOS_READ(RTC_DAY_OF_MONTH); 1061e871be1SJohn Stultz mon = CMOS_READ(RTC_MONTH); 1071e871be1SJohn Stultz year = CMOS_READ(RTC_YEAR); 1081e871be1SJohn Stultz 1091e871be1SJohn Stultz if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { 1101e871be1SJohn Stultz sec = bcd2bin(sec); 1111e871be1SJohn Stultz min = bcd2bin(min); 1121e871be1SJohn Stultz hour = bcd2bin(hour); 1131e871be1SJohn Stultz day = bcd2bin(day); 1141e871be1SJohn Stultz mon = bcd2bin(mon); 1151e871be1SJohn Stultz year = bcd2bin(year); 1161e871be1SJohn Stultz } 1171e871be1SJohn Stultz 1181e871be1SJohn Stultz /* PC-like is standard; used for year >= 70 */ 1191e871be1SJohn Stultz epoch = 1900; 1201e871be1SJohn Stultz if (year < 20) 1211e871be1SJohn Stultz epoch = 2000; 1221e871be1SJohn Stultz else if (year >= 20 && year < 48) 1231e871be1SJohn Stultz /* NT epoch */ 1241e871be1SJohn Stultz epoch = 1980; 1251e871be1SJohn Stultz else if (year >= 48 && year < 70) 1261e871be1SJohn Stultz /* Digital UNIX epoch */ 1271e871be1SJohn Stultz epoch = 1952; 1281e871be1SJohn Stultz 1291e871be1SJohn Stultz printk(KERN_INFO "Using epoch = %d\n", epoch); 1301e871be1SJohn Stultz 1311e871be1SJohn Stultz if ((year += epoch) < 1970) 1321e871be1SJohn Stultz year += 100; 1331e871be1SJohn Stultz 1341e871be1SJohn Stultz ts->tv_sec = mktime(year, mon, day, hour, min, sec); 1351e871be1SJohn Stultz } 1361e871be1SJohn Stultz 1371e871be1SJohn Stultz 1381e871be1SJohn Stultz 1391da177e4SLinus Torvalds /* 1401da177e4SLinus Torvalds * timer_interrupt() needs to keep up the real-time clock, 1411da177e4SLinus Torvalds * as well as call the "do_timer()" routine every clocktick 1421da177e4SLinus Torvalds */ 1438774cb81SAl Viro irqreturn_t timer_interrupt(int irq, void *dev) 1441da177e4SLinus Torvalds { 1451da177e4SLinus Torvalds unsigned long delta; 1461da177e4SLinus Torvalds __u32 now; 1471da177e4SLinus Torvalds long nticks; 1481da177e4SLinus Torvalds 1491da177e4SLinus Torvalds #ifndef CONFIG_SMP 1501da177e4SLinus Torvalds /* Not SMP, do kernel PC profiling here. */ 1518774cb81SAl Viro profile_tick(CPU_PROFILING); 1521da177e4SLinus Torvalds #endif 1531da177e4SLinus Torvalds 1541da177e4SLinus Torvalds write_seqlock(&xtime_lock); 1551da177e4SLinus Torvalds 1561da177e4SLinus Torvalds /* 1571da177e4SLinus Torvalds * Calculate how many ticks have passed since the last update, 1581da177e4SLinus Torvalds * including any previous partial leftover. Save any resulting 1591da177e4SLinus Torvalds * fraction for the next pass. 1601da177e4SLinus Torvalds */ 1611da177e4SLinus Torvalds now = rpcc(); 1621da177e4SLinus Torvalds delta = now - state.last_time; 1631da177e4SLinus Torvalds state.last_time = now; 1641da177e4SLinus Torvalds delta = delta * state.scaled_ticks_per_cycle + state.partial_tick; 1651da177e4SLinus Torvalds state.partial_tick = delta & ((1UL << FIX_SHIFT) - 1); 1661da177e4SLinus Torvalds nticks = delta >> FIX_SHIFT; 1671da177e4SLinus Torvalds 168aa02cd2dSPeter Zijlstra if (nticks) 169aa02cd2dSPeter Zijlstra do_timer(nticks); 1701da177e4SLinus Torvalds 1711da177e4SLinus Torvalds write_sequnlock(&xtime_lock); 172aa02cd2dSPeter Zijlstra 173aa02cd2dSPeter Zijlstra #ifndef CONFIG_SMP 174aa02cd2dSPeter Zijlstra while (nticks--) 175aa02cd2dSPeter Zijlstra update_process_times(user_mode(get_irq_regs())); 176aa02cd2dSPeter Zijlstra #endif 177aa02cd2dSPeter Zijlstra 1781da177e4SLinus Torvalds return IRQ_HANDLED; 1791da177e4SLinus Torvalds } 1801da177e4SLinus Torvalds 181ebaf4fc1SSam Ravnborg void __init 1821da177e4SLinus Torvalds common_init_rtc(void) 1831da177e4SLinus Torvalds { 1841da177e4SLinus Torvalds unsigned char x; 1851da177e4SLinus Torvalds 1861da177e4SLinus Torvalds /* Reset periodic interrupt frequency. */ 1871da177e4SLinus Torvalds x = CMOS_READ(RTC_FREQ_SELECT) & 0x3f; 1881da177e4SLinus Torvalds /* Test includes known working values on various platforms 1891da177e4SLinus Torvalds where 0x26 is wrong; we refuse to change those. */ 1901da177e4SLinus Torvalds if (x != 0x26 && x != 0x25 && x != 0x19 && x != 0x06) { 1911da177e4SLinus Torvalds printk("Setting RTC_FREQ to 1024 Hz (%x)\n", x); 1921da177e4SLinus Torvalds CMOS_WRITE(0x26, RTC_FREQ_SELECT); 1931da177e4SLinus Torvalds } 1941da177e4SLinus Torvalds 1951da177e4SLinus Torvalds /* Turn on periodic interrupts. */ 1961da177e4SLinus Torvalds x = CMOS_READ(RTC_CONTROL); 1971da177e4SLinus Torvalds if (!(x & RTC_PIE)) { 1981da177e4SLinus Torvalds printk("Turning on RTC interrupts.\n"); 1991da177e4SLinus Torvalds x |= RTC_PIE; 2001da177e4SLinus Torvalds x &= ~(RTC_AIE | RTC_UIE); 2011da177e4SLinus Torvalds CMOS_WRITE(x, RTC_CONTROL); 2021da177e4SLinus Torvalds } 2031da177e4SLinus Torvalds (void) CMOS_READ(RTC_INTR_FLAGS); 2041da177e4SLinus Torvalds 2051da177e4SLinus Torvalds outb(0x36, 0x43); /* pit counter 0: system timer */ 2061da177e4SLinus Torvalds outb(0x00, 0x40); 2071da177e4SLinus Torvalds outb(0x00, 0x40); 2081da177e4SLinus Torvalds 2091da177e4SLinus Torvalds outb(0xb6, 0x43); /* pit counter 2: speaker */ 2101da177e4SLinus Torvalds outb(0x31, 0x42); 2111da177e4SLinus Torvalds outb(0x13, 0x42); 2121da177e4SLinus Torvalds 2131da177e4SLinus Torvalds init_rtc_irq(); 2141da177e4SLinus Torvalds } 2151da177e4SLinus Torvalds 2165f7dc5d7SIvan Kokshaysky unsigned int common_get_rtc_time(struct rtc_time *time) 2175f7dc5d7SIvan Kokshaysky { 2185f7dc5d7SIvan Kokshaysky return __get_rtc_time(time); 2195f7dc5d7SIvan Kokshaysky } 2205f7dc5d7SIvan Kokshaysky 2215f7dc5d7SIvan Kokshaysky int common_set_rtc_time(struct rtc_time *time) 2225f7dc5d7SIvan Kokshaysky { 2235f7dc5d7SIvan Kokshaysky return __set_rtc_time(time); 2245f7dc5d7SIvan Kokshaysky } 2251da177e4SLinus Torvalds 2261da177e4SLinus Torvalds /* Validate a computed cycle counter result against the known bounds for 2271da177e4SLinus Torvalds the given processor core. There's too much brokenness in the way of 2281da177e4SLinus Torvalds timing hardware for any one method to work everywhere. :-( 2291da177e4SLinus Torvalds 2301da177e4SLinus Torvalds Return 0 if the result cannot be trusted, otherwise return the argument. */ 2311da177e4SLinus Torvalds 2321da177e4SLinus Torvalds static unsigned long __init 2331da177e4SLinus Torvalds validate_cc_value(unsigned long cc) 2341da177e4SLinus Torvalds { 2351da177e4SLinus Torvalds static struct bounds { 2361da177e4SLinus Torvalds unsigned int min, max; 2371da177e4SLinus Torvalds } cpu_hz[] __initdata = { 2381da177e4SLinus Torvalds [EV3_CPU] = { 50000000, 200000000 }, /* guess */ 2391da177e4SLinus Torvalds [EV4_CPU] = { 100000000, 300000000 }, 2401da177e4SLinus Torvalds [LCA4_CPU] = { 100000000, 300000000 }, /* guess */ 2411da177e4SLinus Torvalds [EV45_CPU] = { 200000000, 300000000 }, 2421da177e4SLinus Torvalds [EV5_CPU] = { 250000000, 433000000 }, 2431da177e4SLinus Torvalds [EV56_CPU] = { 333000000, 667000000 }, 2441da177e4SLinus Torvalds [PCA56_CPU] = { 400000000, 600000000 }, /* guess */ 2451da177e4SLinus Torvalds [PCA57_CPU] = { 500000000, 600000000 }, /* guess */ 2461da177e4SLinus Torvalds [EV6_CPU] = { 466000000, 600000000 }, 2471da177e4SLinus Torvalds [EV67_CPU] = { 600000000, 750000000 }, 2481da177e4SLinus Torvalds [EV68AL_CPU] = { 750000000, 940000000 }, 2491da177e4SLinus Torvalds [EV68CB_CPU] = { 1000000000, 1333333333 }, 2501da177e4SLinus Torvalds /* None of the following are shipping as of 2001-11-01. */ 2511da177e4SLinus Torvalds [EV68CX_CPU] = { 1000000000, 1700000000 }, /* guess */ 2521da177e4SLinus Torvalds [EV69_CPU] = { 1000000000, 1700000000 }, /* guess */ 2531da177e4SLinus Torvalds [EV7_CPU] = { 800000000, 1400000000 }, /* guess */ 2541da177e4SLinus Torvalds [EV79_CPU] = { 1000000000, 2000000000 }, /* guess */ 2551da177e4SLinus Torvalds }; 2561da177e4SLinus Torvalds 2571da177e4SLinus Torvalds /* Allow for some drift in the crystal. 10MHz is more than enough. */ 2581da177e4SLinus Torvalds const unsigned int deviation = 10000000; 2591da177e4SLinus Torvalds 2601da177e4SLinus Torvalds struct percpu_struct *cpu; 2611da177e4SLinus Torvalds unsigned int index; 2621da177e4SLinus Torvalds 2631da177e4SLinus Torvalds cpu = (struct percpu_struct *)((char*)hwrpb + hwrpb->processor_offset); 2641da177e4SLinus Torvalds index = cpu->type & 0xffffffff; 2651da177e4SLinus Torvalds 2661da177e4SLinus Torvalds /* If index out of bounds, no way to validate. */ 26725c8716cSTobias Klauser if (index >= ARRAY_SIZE(cpu_hz)) 2681da177e4SLinus Torvalds return cc; 2691da177e4SLinus Torvalds 2701da177e4SLinus Torvalds /* If index contains no data, no way to validate. */ 2711da177e4SLinus Torvalds if (cpu_hz[index].max == 0) 2721da177e4SLinus Torvalds return cc; 2731da177e4SLinus Torvalds 2741da177e4SLinus Torvalds if (cc < cpu_hz[index].min - deviation 2751da177e4SLinus Torvalds || cc > cpu_hz[index].max + deviation) 2761da177e4SLinus Torvalds return 0; 2771da177e4SLinus Torvalds 2781da177e4SLinus Torvalds return cc; 2791da177e4SLinus Torvalds } 2801da177e4SLinus Torvalds 2811da177e4SLinus Torvalds 2821da177e4SLinus Torvalds /* 2831da177e4SLinus Torvalds * Calibrate CPU clock using legacy 8254 timer/counter. Stolen from 2841da177e4SLinus Torvalds * arch/i386/time.c. 2851da177e4SLinus Torvalds */ 2861da177e4SLinus Torvalds 2871da177e4SLinus Torvalds #define CALIBRATE_LATCH 0xffff 2881da177e4SLinus Torvalds #define TIMEOUT_COUNT 0x100000 2891da177e4SLinus Torvalds 2901da177e4SLinus Torvalds static unsigned long __init 2911da177e4SLinus Torvalds calibrate_cc_with_pit(void) 2921da177e4SLinus Torvalds { 2931da177e4SLinus Torvalds int cc, count = 0; 2941da177e4SLinus Torvalds 2951da177e4SLinus Torvalds /* Set the Gate high, disable speaker */ 2961da177e4SLinus Torvalds outb((inb(0x61) & ~0x02) | 0x01, 0x61); 2971da177e4SLinus Torvalds 2981da177e4SLinus Torvalds /* 2991da177e4SLinus Torvalds * Now let's take care of CTC channel 2 3001da177e4SLinus Torvalds * 3011da177e4SLinus Torvalds * Set the Gate high, program CTC channel 2 for mode 0, 3021da177e4SLinus Torvalds * (interrupt on terminal count mode), binary count, 3031da177e4SLinus Torvalds * load 5 * LATCH count, (LSB and MSB) to begin countdown. 3041da177e4SLinus Torvalds */ 3051da177e4SLinus Torvalds outb(0xb0, 0x43); /* binary, mode 0, LSB/MSB, Ch 2 */ 3061da177e4SLinus Torvalds outb(CALIBRATE_LATCH & 0xff, 0x42); /* LSB of count */ 3071da177e4SLinus Torvalds outb(CALIBRATE_LATCH >> 8, 0x42); /* MSB of count */ 3081da177e4SLinus Torvalds 3091da177e4SLinus Torvalds cc = rpcc(); 3101da177e4SLinus Torvalds do { 3111da177e4SLinus Torvalds count++; 3121da177e4SLinus Torvalds } while ((inb(0x61) & 0x20) == 0 && count < TIMEOUT_COUNT); 3131da177e4SLinus Torvalds cc = rpcc() - cc; 3141da177e4SLinus Torvalds 3151da177e4SLinus Torvalds /* Error: ECTCNEVERSET or ECPUTOOFAST. */ 3161da177e4SLinus Torvalds if (count <= 1 || count == TIMEOUT_COUNT) 3171da177e4SLinus Torvalds return 0; 3181da177e4SLinus Torvalds 3191da177e4SLinus Torvalds return ((long)cc * PIT_TICK_RATE) / (CALIBRATE_LATCH + 1); 3201da177e4SLinus Torvalds } 3211da177e4SLinus Torvalds 3221da177e4SLinus Torvalds /* The Linux interpretation of the CMOS clock register contents: 3231da177e4SLinus Torvalds When the Update-In-Progress (UIP) flag goes from 1 to 0, the 3241da177e4SLinus Torvalds RTC registers show the second which has precisely just started. 3251da177e4SLinus Torvalds Let's hope other operating systems interpret the RTC the same way. */ 3261da177e4SLinus Torvalds 3271da177e4SLinus Torvalds static unsigned long __init 3281da177e4SLinus Torvalds rpcc_after_update_in_progress(void) 3291da177e4SLinus Torvalds { 3301da177e4SLinus Torvalds do { } while (!(CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP)); 3311da177e4SLinus Torvalds do { } while (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP); 3321da177e4SLinus Torvalds 3331da177e4SLinus Torvalds return rpcc(); 3341da177e4SLinus Torvalds } 3351da177e4SLinus Torvalds 3369ce34c8fSJohn Stultz #ifndef CONFIG_SMP 3379ce34c8fSJohn Stultz /* Until and unless we figure out how to get cpu cycle counters 3389ce34c8fSJohn Stultz in sync and keep them there, we can't use the rpcc. */ 3399ce34c8fSJohn Stultz static cycle_t read_rpcc(struct clocksource *cs) 3409ce34c8fSJohn Stultz { 3419ce34c8fSJohn Stultz cycle_t ret = (cycle_t)rpcc(); 3429ce34c8fSJohn Stultz return ret; 3439ce34c8fSJohn Stultz } 3449ce34c8fSJohn Stultz 3459ce34c8fSJohn Stultz static struct clocksource clocksource_rpcc = { 3469ce34c8fSJohn Stultz .name = "rpcc", 3479ce34c8fSJohn Stultz .rating = 300, 3489ce34c8fSJohn Stultz .read = read_rpcc, 3499ce34c8fSJohn Stultz .mask = CLOCKSOURCE_MASK(32), 3509ce34c8fSJohn Stultz .flags = CLOCK_SOURCE_IS_CONTINUOUS 3519ce34c8fSJohn Stultz }; 3529ce34c8fSJohn Stultz 3539ce34c8fSJohn Stultz static inline void register_rpcc_clocksource(long cycle_freq) 3549ce34c8fSJohn Stultz { 3559ce34c8fSJohn Stultz clocksource_calc_mult_shift(&clocksource_rpcc, cycle_freq, 4); 3569ce34c8fSJohn Stultz clocksource_register(&clocksource_rpcc); 3579ce34c8fSJohn Stultz } 3589ce34c8fSJohn Stultz #else /* !CONFIG_SMP */ 3599ce34c8fSJohn Stultz static inline void register_rpcc_clocksource(long cycle_freq) 3609ce34c8fSJohn Stultz { 3619ce34c8fSJohn Stultz } 3629ce34c8fSJohn Stultz #endif /* !CONFIG_SMP */ 3639ce34c8fSJohn Stultz 3641da177e4SLinus Torvalds void __init 3651da177e4SLinus Torvalds time_init(void) 3661da177e4SLinus Torvalds { 3671e871be1SJohn Stultz unsigned int cc1, cc2; 3681da177e4SLinus Torvalds unsigned long cycle_freq, tolerance; 3691da177e4SLinus Torvalds long diff; 3701da177e4SLinus Torvalds 3711da177e4SLinus Torvalds /* Calibrate CPU clock -- attempt #1. */ 3721da177e4SLinus Torvalds if (!est_cycle_freq) 3731da177e4SLinus Torvalds est_cycle_freq = validate_cc_value(calibrate_cc_with_pit()); 3741da177e4SLinus Torvalds 3754c2e6f6aSMatt Mackall cc1 = rpcc(); 3761da177e4SLinus Torvalds 3771da177e4SLinus Torvalds /* Calibrate CPU clock -- attempt #2. */ 3781da177e4SLinus Torvalds if (!est_cycle_freq) { 3794c2e6f6aSMatt Mackall cc1 = rpcc_after_update_in_progress(); 3801da177e4SLinus Torvalds cc2 = rpcc_after_update_in_progress(); 3811da177e4SLinus Torvalds est_cycle_freq = validate_cc_value(cc2 - cc1); 3821da177e4SLinus Torvalds cc1 = cc2; 3831da177e4SLinus Torvalds } 3841da177e4SLinus Torvalds 3851da177e4SLinus Torvalds cycle_freq = hwrpb->cycle_freq; 3861da177e4SLinus Torvalds if (est_cycle_freq) { 3871da177e4SLinus Torvalds /* If the given value is within 250 PPM of what we calculated, 3881da177e4SLinus Torvalds accept it. Otherwise, use what we found. */ 3891da177e4SLinus Torvalds tolerance = cycle_freq / 4000; 3901da177e4SLinus Torvalds diff = cycle_freq - est_cycle_freq; 3911da177e4SLinus Torvalds if (diff < 0) 3921da177e4SLinus Torvalds diff = -diff; 3931da177e4SLinus Torvalds if ((unsigned long)diff > tolerance) { 3941da177e4SLinus Torvalds cycle_freq = est_cycle_freq; 3951da177e4SLinus Torvalds printk("HWRPB cycle frequency bogus. " 3961da177e4SLinus Torvalds "Estimated %lu Hz\n", cycle_freq); 3971da177e4SLinus Torvalds } else { 3981da177e4SLinus Torvalds est_cycle_freq = 0; 3991da177e4SLinus Torvalds } 4001da177e4SLinus Torvalds } else if (! validate_cc_value (cycle_freq)) { 4011da177e4SLinus Torvalds printk("HWRPB cycle frequency bogus, " 4021da177e4SLinus Torvalds "and unable to estimate a proper value!\n"); 4031da177e4SLinus Torvalds } 4041da177e4SLinus Torvalds 4051da177e4SLinus Torvalds /* From John Bowman <bowman@math.ualberta.ca>: allow the values 4061da177e4SLinus Torvalds to settle, as the Update-In-Progress bit going low isn't good 4071da177e4SLinus Torvalds enough on some hardware. 2ms is our guess; we haven't found 4081da177e4SLinus Torvalds bogomips yet, but this is close on a 500Mhz box. */ 4091da177e4SLinus Torvalds __delay(1000000); 4101da177e4SLinus Torvalds 4111da177e4SLinus Torvalds 4121da177e4SLinus Torvalds if (HZ > (1<<16)) { 4131da177e4SLinus Torvalds extern void __you_loose (void); 4141da177e4SLinus Torvalds __you_loose(); 4151da177e4SLinus Torvalds } 4161da177e4SLinus Torvalds 4179ce34c8fSJohn Stultz register_rpcc_clocksource(cycle_freq); 4189ce34c8fSJohn Stultz 4191da177e4SLinus Torvalds state.last_time = cc1; 4201da177e4SLinus Torvalds state.scaled_ticks_per_cycle 4211da177e4SLinus Torvalds = ((unsigned long) HZ << FIX_SHIFT) / cycle_freq; 4221da177e4SLinus Torvalds state.partial_tick = 0L; 4231da177e4SLinus Torvalds 4241da177e4SLinus Torvalds /* Startup the timer source. */ 4251da177e4SLinus Torvalds alpha_mv.init_rtc(); 4261da177e4SLinus Torvalds } 4271da177e4SLinus Torvalds 4281da177e4SLinus Torvalds /* 4291da177e4SLinus Torvalds * In order to set the CMOS clock precisely, set_rtc_mmss has to be 4301da177e4SLinus Torvalds * called 500 ms after the second nowtime has started, because when 4311da177e4SLinus Torvalds * nowtime is written into the registers of the CMOS clock, it will 4321da177e4SLinus Torvalds * jump to the next second precisely 500 ms later. Check the Motorola 4331da177e4SLinus Torvalds * MC146818A or Dallas DS12887 data sheet for details. 4341da177e4SLinus Torvalds * 4351da177e4SLinus Torvalds * BUG: This routine does not handle hour overflow properly; it just 4361da177e4SLinus Torvalds * sets the minutes. Usually you won't notice until after reboot! 4371da177e4SLinus Torvalds */ 4381da177e4SLinus Torvalds 4391da177e4SLinus Torvalds 4401da177e4SLinus Torvalds static int 4411da177e4SLinus Torvalds set_rtc_mmss(unsigned long nowtime) 4421da177e4SLinus Torvalds { 4431da177e4SLinus Torvalds int retval = 0; 4441da177e4SLinus Torvalds int real_seconds, real_minutes, cmos_minutes; 4451da177e4SLinus Torvalds unsigned char save_control, save_freq_select; 4461da177e4SLinus Torvalds 4471da177e4SLinus Torvalds /* irq are locally disabled here */ 4481da177e4SLinus Torvalds spin_lock(&rtc_lock); 4491da177e4SLinus Torvalds /* Tell the clock it's being set */ 4501da177e4SLinus Torvalds save_control = CMOS_READ(RTC_CONTROL); 4511da177e4SLinus Torvalds CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL); 4521da177e4SLinus Torvalds 4531da177e4SLinus Torvalds /* Stop and reset prescaler */ 4541da177e4SLinus Torvalds save_freq_select = CMOS_READ(RTC_FREQ_SELECT); 4551da177e4SLinus Torvalds CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT); 4561da177e4SLinus Torvalds 4571da177e4SLinus Torvalds cmos_minutes = CMOS_READ(RTC_MINUTES); 4581da177e4SLinus Torvalds if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) 45918b1bd05SAdrian Bunk cmos_minutes = bcd2bin(cmos_minutes); 4601da177e4SLinus Torvalds 4611da177e4SLinus Torvalds /* 4621da177e4SLinus Torvalds * since we're only adjusting minutes and seconds, 4631da177e4SLinus Torvalds * don't interfere with hour overflow. This avoids 4641da177e4SLinus Torvalds * messing with unknown time zones but requires your 4651da177e4SLinus Torvalds * RTC not to be off by more than 15 minutes 4661da177e4SLinus Torvalds */ 4671da177e4SLinus Torvalds real_seconds = nowtime % 60; 4681da177e4SLinus Torvalds real_minutes = nowtime / 60; 4691da177e4SLinus Torvalds if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1) { 4701da177e4SLinus Torvalds /* correct for half hour time zone */ 4711da177e4SLinus Torvalds real_minutes += 30; 4721da177e4SLinus Torvalds } 4731da177e4SLinus Torvalds real_minutes %= 60; 4741da177e4SLinus Torvalds 4751da177e4SLinus Torvalds if (abs(real_minutes - cmos_minutes) < 30) { 4761da177e4SLinus Torvalds if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { 47718b1bd05SAdrian Bunk real_seconds = bin2bcd(real_seconds); 47818b1bd05SAdrian Bunk real_minutes = bin2bcd(real_minutes); 4791da177e4SLinus Torvalds } 4801da177e4SLinus Torvalds CMOS_WRITE(real_seconds,RTC_SECONDS); 4811da177e4SLinus Torvalds CMOS_WRITE(real_minutes,RTC_MINUTES); 4821da177e4SLinus Torvalds } else { 4831da177e4SLinus Torvalds printk(KERN_WARNING 4841da177e4SLinus Torvalds "set_rtc_mmss: can't update from %d to %d\n", 4851da177e4SLinus Torvalds cmos_minutes, real_minutes); 4861da177e4SLinus Torvalds retval = -1; 4871da177e4SLinus Torvalds } 4881da177e4SLinus Torvalds 4891da177e4SLinus Torvalds /* The following flags have to be released exactly in this order, 4901da177e4SLinus Torvalds * otherwise the DS12887 (popular MC146818A clone with integrated 4911da177e4SLinus Torvalds * battery and quartz) will not reset the oscillator and will not 4921da177e4SLinus Torvalds * update precisely 500 ms later. You won't find this mentioned in 4931da177e4SLinus Torvalds * the Dallas Semiconductor data sheets, but who believes data 4941da177e4SLinus Torvalds * sheets anyway ... -- Markus Kuhn 4951da177e4SLinus Torvalds */ 4961da177e4SLinus Torvalds CMOS_WRITE(save_control, RTC_CONTROL); 4971da177e4SLinus Torvalds CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT); 4981da177e4SLinus Torvalds spin_unlock(&rtc_lock); 4991da177e4SLinus Torvalds 5001da177e4SLinus Torvalds return retval; 5011da177e4SLinus Torvalds } 502