From 85d0b3a573d8b711ee0c96199ac24a0f3283ed68 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Sat, 13 Jul 2013 15:49:45 -0700 Subject: alpha: Reorganize rtc handling Discontinue use of GENERIC_CMOS_UPDATE; rely on the RTC subsystem. The marvel platform requires that the rtc only be touched from the boot cpu. This had been partially implemented with hooks for get/set_rtc_time, but read/update_persistent_clock were not handled. Move the hooks from the machine_vec to a special rtc_class_ops struct. We had read_persistent_clock managing the epoch against which the rtc hw is based, but this didn't apply to get_rtc_time or set_rtc_time. This resulted in incorrect values when hwclock(8) gets involved. Allow the epoch to be set from the kernel command-line, overriding the autodetection, which is doomed to fail in 2020. Further, by implementing the rtc ioctl function, we can expose this epoch to userland. Elide the alarm functions that RTC_DRV_CMOS implements. This was highly questionable on Alpha, since the interrupt is used by the system timer. Signed-off-by: Richard Henderson --- arch/alpha/kernel/time.c | 146 +---------------------------------------------- 1 file changed, 1 insertion(+), 145 deletions(-) (limited to 'arch/alpha/kernel/time.c') diff --git a/arch/alpha/kernel/time.c b/arch/alpha/kernel/time.c index a6bcb31..4c6c0fe 100644 --- a/arch/alpha/kernel/time.c +++ b/arch/alpha/kernel/time.c @@ -3,13 +3,7 @@ * * Copyright (C) 1991, 1992, 1995, 1999, 2000 Linus Torvalds * - * This file contains the PC-specific time handling details: - * reading the RTC at bootup, etc.. - * 1994-07-02 Alan Modra - * fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime - * 1995-03-26 Markus Kuhn - * fixed 500 ms bug at call to set_rtc_mmss, fixed DS12887 - * precision CMOS clock update + * This file contains the clocksource time handling. * 1997-09-10 Updated NTP code according to technical memorandum Jan '96 * "A Kernel Model for Precision Timekeeping" by Dave Mills * 1997-01-09 Adrian Sun @@ -21,9 +15,6 @@ * 1999-04-16 Thorsten Kranzkowski (dl8bcu@gmx.net) * fixed algorithm in do_gettimeofday() for calculating the precise time * from processor cycle counter (now taking lost_ticks into account) - * 2000-08-13 Jan-Benedict Glaw - * Fixed time_init to be aware of epoches != 1900. This prevents - * booting up in 2048 for me;) Code is stolen from rtc.c. * 2003-06-03 R. Scott Bailey * Tighten sanity in time_init from 1% (10,000 PPM) to 250 PPM */ @@ -46,7 +37,6 @@ #include #include #include -#include #include #include @@ -56,8 +46,6 @@ #include "proto.h" #include "irq_impl.h" -static int set_rtc_mmss(unsigned long); - DEFINE_SPINLOCK(rtc_lock); EXPORT_SYMBOL(rtc_lock); @@ -108,53 +96,6 @@ static inline __u32 rpcc(void) return __builtin_alpha_rpcc(); } -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); - ts->tv_nsec = 0; -} - - - /* * timer_interrupt() needs to keep up the real-time clock, * as well as call the "xtime_update()" routine every clocktick @@ -243,16 +184,6 @@ common_init_rtc(void) init_rtc_irq(); } -unsigned int common_get_rtc_time(struct rtc_time *time) -{ - return __get_rtc_time(time); -} - -int common_set_rtc_time(struct rtc_time *time) -{ - return __set_rtc_time(time); -} - /* Validate a computed cycle counter result against the known bounds for the given processor core. There's too much brokenness in the way of timing hardware for any one method to work everywhere. :-( @@ -453,78 +384,3 @@ time_init(void) /* Startup the timer source. */ alpha_mv.init_rtc(); } - -/* - * 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 - * jump to the next second precisely 500 ms later. Check the Motorola - * MC146818A or Dallas DS12887 data sheet for details. - * - * BUG: This routine does not handle hour overflow properly; it just - * sets the minutes. Usually you won't notice until after reboot! - */ - - -static int -set_rtc_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) { - /* correct for half hour time zone */ - real_minutes += 30; - } - 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_once(KERN_NOTICE - "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 DS12887 (popular MC146818A clone with integrated - * battery and quartz) 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; -} -- cgit v1.1