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authorRichard Henderson <rth@twiddle.net>2013-07-14 02:49:45 +0400
committerMatt Turner <mattst88@gmail.com>2013-11-17 04:33:16 +0400
commit85d0b3a573d8b711ee0c96199ac24a0f3283ed68 (patch)
treee3ccfb8221bac388dc44fcc068ab1b32f67839a3 /arch/alpha/kernel/time.c
parent7f3bbb82e0c371d6881129f776c90130ba66f051 (diff)
downloadlinux-85d0b3a573d8b711ee0c96199ac24a0f3283ed68.tar.xz
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 <rth@twiddle.net>
Diffstat (limited to 'arch/alpha/kernel/time.c')
-rw-r--r--arch/alpha/kernel/time.c146
1 files changed, 1 insertions, 145 deletions
diff --git a/arch/alpha/kernel/time.c b/arch/alpha/kernel/time.c
index a6bcb3113d81..4c6c0fe47a7b 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 <jbglaw@lug-owl.de>
- * 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 <scott.bailey@eds.com>
* Tighten sanity in time_init from 1% (10,000 PPM) to 250 PPM
*/
@@ -46,7 +37,6 @@
#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/hwrpb.h>
-#include <asm/rtc.h>
#include <linux/mc146818rtc.h>
#include <linux/time.h>
@@ -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;
-}