diff options
Diffstat (limited to 'arch/alpha/kernel/time.c')
| -rw-r--r-- | arch/alpha/kernel/time.c | 170 |
1 files changed, 78 insertions, 92 deletions
diff --git a/arch/alpha/kernel/time.c b/arch/alpha/kernel/time.c index 5d0826654c6..1efbed82c0f 100644 --- a/arch/alpha/kernel/time.c +++ b/arch/alpha/kernel/time.c @@ -51,6 +51,7 @@ #include <linux/mc146818rtc.h> #include <linux/time.h> #include <linux/timex.h> +#include <linux/clocksource.h> #include "proto.h" #include "irq_impl.h" @@ -75,8 +76,6 @@ static struct { __u32 last_time; /* ticks/cycle * 2^48 */ unsigned long scaled_ticks_per_cycle; - /* last time the CMOS clock got updated */ - time_t last_rtc_update; /* partial unused tick */ unsigned long partial_tick; } state; @@ -91,6 +90,52 @@ static inline __u32 rpcc(void) return result; } +int update_persistent_clock(struct timespec now) +{ + return set_rtc_mmss(now.tv_sec); +} + +void read_persistent_clock(struct timespec *ts) +{ + unsigned int year, mon, day, hour, min, sec, epoch; + + 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); + + 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); + } + + /* PC-like is standard; used for year >= 70 */ + epoch = 1900; + if (year < 20) + epoch = 2000; + else if (year >= 20 && year < 48) + /* NT epoch */ + epoch = 1980; + else if (year >= 48 && year < 70) + /* Digital UNIX epoch */ + epoch = 1952; + + printk(KERN_INFO "Using epoch = %d\n", epoch); + + if ((year += epoch) < 1970) + year += 100; + + ts->tv_sec = mktime(year, mon, day, hour, min, sec); +} + + + /* * timer_interrupt() needs to keep up the real-time clock, * as well as call the "do_timer()" routine every clocktick @@ -123,19 +168,6 @@ irqreturn_t timer_interrupt(int irq, void *dev) if (nticks) do_timer(nticks); - /* - * If we have an externally synchronized Linux clock, then update - * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be - * called as close as possible to 500 ms before the new second starts. - */ - if (ntp_synced() - && xtime.tv_sec > state.last_rtc_update + 660 - && xtime.tv_nsec >= 500000 - ((unsigned) TICK_SIZE) / 2 - && xtime.tv_nsec <= 500000 + ((unsigned) TICK_SIZE) / 2) { - int tmp = set_rtc_mmss(xtime.tv_sec); - state.last_rtc_update = xtime.tv_sec - (tmp ? 600 : 0); - } - write_sequnlock(&xtime_lock); #ifndef CONFIG_SMP @@ -301,10 +333,38 @@ rpcc_after_update_in_progress(void) return rpcc(); } +#ifndef CONFIG_SMP +/* Until and unless we figure out how to get cpu cycle counters + in sync and keep them there, we can't use the rpcc. */ +static cycle_t read_rpcc(struct clocksource *cs) +{ + cycle_t ret = (cycle_t)rpcc(); + return ret; +} + +static struct clocksource clocksource_rpcc = { + .name = "rpcc", + .rating = 300, + .read = read_rpcc, + .mask = CLOCKSOURCE_MASK(32), + .flags = CLOCK_SOURCE_IS_CONTINUOUS +}; + +static inline void register_rpcc_clocksource(long cycle_freq) +{ + clocksource_calc_mult_shift(&clocksource_rpcc, cycle_freq, 4); + clocksource_register(&clocksource_rpcc); +} +#else /* !CONFIG_SMP */ +static inline void register_rpcc_clocksource(long cycle_freq) +{ +} +#endif /* !CONFIG_SMP */ + void __init time_init(void) { - unsigned int year, mon, day, hour, min, sec, cc1, cc2, epoch; + unsigned int cc1, cc2; unsigned long cycle_freq, tolerance; long diff; @@ -348,53 +408,17 @@ time_init(void) bogomips yet, but this is close on a 500Mhz box. */ __delay(1000000); - 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); - - 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); - } - - /* PC-like is standard; used for year >= 70 */ - epoch = 1900; - if (year < 20) - epoch = 2000; - else if (year >= 20 && year < 48) - /* NT epoch */ - epoch = 1980; - else if (year >= 48 && year < 70) - /* Digital UNIX epoch */ - epoch = 1952; - - printk(KERN_INFO "Using epoch = %d\n", epoch); - - if ((year += epoch) < 1970) - year += 100; - - xtime.tv_sec = mktime(year, mon, day, hour, min, sec); - xtime.tv_nsec = 0; - - wall_to_monotonic.tv_sec -= xtime.tv_sec; - wall_to_monotonic.tv_nsec = 0; if (HZ > (1<<16)) { extern void __you_loose (void); __you_loose(); } + register_rpcc_clocksource(cycle_freq); + state.last_time = cc1; state.scaled_ticks_per_cycle = ((unsigned long) HZ << FIX_SHIFT) / cycle_freq; - state.last_rtc_update = 0; state.partial_tick = 0L; /* Startup the timer source. */ @@ -402,44 +426,6 @@ time_init(void) } /* - * Use the cycle counter to estimate an displacement from the last time - * tick. Unfortunately the Alpha designers made only the low 32-bits of - * the cycle counter active, so we overflow on 8.2 seconds on a 500MHz - * part. So we can't do the "find absolute time in terms of cycles" thing - * that the other ports do. - */ -u32 arch_gettimeoffset(void) -{ -#ifdef CONFIG_SMP - /* Until and unless we figure out how to get cpu cycle counters - in sync and keep them there, we can't use the rpcc tricks. */ - return 0; -#else - unsigned long delta_cycles, delta_usec, partial_tick; - - delta_cycles = rpcc() - state.last_time; - partial_tick = state.partial_tick; - /* - * usec = cycles * ticks_per_cycle * 2**48 * 1e6 / (2**48 * ticks) - * = cycles * (s_t_p_c) * 1e6 / (2**48 * ticks) - * = cycles * (s_t_p_c) * 15625 / (2**42 * ticks) - * - * which, given a 600MHz cycle and a 1024Hz tick, has a - * dynamic range of about 1.7e17, which is less than the - * 1.8e19 in an unsigned long, so we are safe from overflow. - * - * Round, but with .5 up always, since .5 to even is harder - * with no clear gain. - */ - - delta_usec = (delta_cycles * state.scaled_ticks_per_cycle - + partial_tick) * 15625; - delta_usec = ((delta_usec / ((1UL << (FIX_SHIFT-6-1)) * HZ)) + 1) / 2; - return delta_usec * 1000; -#endif -} - -/* * In order to set the CMOS clock precisely, set_rtc_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 |