/*
|
/*
|
* linux/arch/i386/kernel/time.c
|
* linux/arch/i386/kernel/time.c
|
*
|
*
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* Copyright (C) 1991, 1992, 1995 Linus Torvalds
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* Copyright (C) 1991, 1992, 1995 Linus Torvalds
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*
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*
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* This file contains the PC-specific time handling details:
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* This file contains the PC-specific time handling details:
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* reading the RTC at bootup, etc..
|
* reading the RTC at bootup, etc..
|
* 1994-07-02 Alan Modra
|
* 1994-07-02 Alan Modra
|
* fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime
|
* fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime
|
* 1995-03-26 Markus Kuhn
|
* 1995-03-26 Markus Kuhn
|
* fixed 500 ms bug at call to set_rtc_mmss, fixed DS12887
|
* fixed 500 ms bug at call to set_rtc_mmss, fixed DS12887
|
* precision CMOS clock update
|
* precision CMOS clock update
|
* 1996-05-03 Ingo Molnar
|
* 1996-05-03 Ingo Molnar
|
* fixed time warps in do_[slow|fast]_gettimeoffset()
|
* fixed time warps in do_[slow|fast]_gettimeoffset()
|
* 1997-09-10 Updated NTP code according to technical memorandum Jan '96
|
* 1997-09-10 Updated NTP code according to technical memorandum Jan '96
|
* "A Kernel Model for Precision Timekeeping" by Dave Mills
|
* "A Kernel Model for Precision Timekeeping" by Dave Mills
|
*/
|
*/
|
#include <linux/errno.h>
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#include <linux/errno.h>
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#include <linux/sched.h>
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/kernel.h>
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#include <linux/param.h>
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#include <linux/param.h>
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#include <linux/string.h>
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#include <linux/string.h>
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#include <linux/mm.h>
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#include <linux/mm.h>
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#include <linux/interrupt.h>
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#include <linux/interrupt.h>
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#include <linux/time.h>
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#include <linux/time.h>
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#include <linux/delay.h>
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#include <linux/delay.h>
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|
|
#include <asm/segment.h>
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#include <asm/segment.h>
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#include <asm/io.h>
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#include <asm/io.h>
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#include <asm/irq.h>
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#include <asm/irq.h>
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#include <asm/delay.h>
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#include <asm/delay.h>
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|
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#include <linux/mc146818rtc.h>
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#include <linux/mc146818rtc.h>
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#include <linux/timex.h>
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#include <linux/timex.h>
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#include <linux/config.h>
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#include <linux/config.h>
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|
|
extern int setup_x86_irq(int, struct irqaction *);
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extern int setup_x86_irq(int, struct irqaction *);
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|
|
#ifndef CONFIG_APM /* cycle counter may be unreliable */
|
#ifndef CONFIG_APM /* cycle counter may be unreliable */
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/* Cycle counter value at the previous timer interrupt.. */
|
/* Cycle counter value at the previous timer interrupt.. */
|
static struct {
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static struct {
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unsigned long low;
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unsigned long low;
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unsigned long high;
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unsigned long high;
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} init_timer_cc, last_timer_cc;
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} init_timer_cc, last_timer_cc;
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|
|
/*
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/*
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* This is more assembly than C, but it's also rather
|
* This is more assembly than C, but it's also rather
|
* timing-critical and we have to use assembler to get
|
* timing-critical and we have to use assembler to get
|
* reasonable 64-bit arithmetic
|
* reasonable 64-bit arithmetic
|
*/
|
*/
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static unsigned long do_fast_gettimeoffset(void)
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static unsigned long do_fast_gettimeoffset(void)
|
{
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{
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register unsigned long eax asm("ax");
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register unsigned long eax asm("ax");
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register unsigned long edx asm("dx");
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register unsigned long edx asm("dx");
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unsigned long tmp, quotient, low_timer, missing_time;
|
unsigned long tmp, quotient, low_timer, missing_time;
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|
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/* Last jiffy when do_fast_gettimeoffset() was called.. */
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/* Last jiffy when do_fast_gettimeoffset() was called.. */
|
static unsigned long last_jiffies=0;
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static unsigned long last_jiffies=0;
|
|
|
/* Cached "clocks per usec" value.. */
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/* Cached "clocks per usec" value.. */
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static unsigned long cached_quotient=0;
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static unsigned long cached_quotient=0;
|
|
|
/* The "clocks per usec" value is calculated once each jiffy */
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/* The "clocks per usec" value is calculated once each jiffy */
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tmp = jiffies;
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tmp = jiffies;
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quotient = cached_quotient;
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quotient = cached_quotient;
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low_timer = last_timer_cc.low;
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low_timer = last_timer_cc.low;
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missing_time = 0;
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missing_time = 0;
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if (last_jiffies != tmp) {
|
if (last_jiffies != tmp) {
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last_jiffies = tmp;
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last_jiffies = tmp;
|
/*
|
/*
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* test for hanging bottom handler (this means xtime is not
|
* test for hanging bottom handler (this means xtime is not
|
* updated yet)
|
* updated yet)
|
*/
|
*/
|
if (test_bit(TIMER_BH, &bh_active) )
|
if (test_bit(TIMER_BH, &bh_active) )
|
{
|
{
|
missing_time = 1000020/HZ;
|
missing_time = 1000020/HZ;
|
}
|
}
|
|
|
/* Get last timer tick in absolute kernel time */
|
/* Get last timer tick in absolute kernel time */
|
eax = low_timer;
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eax = low_timer;
|
edx = last_timer_cc.high;
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edx = last_timer_cc.high;
|
__asm__("subl "SYMBOL_NAME_STR(init_timer_cc)",%0\n\t"
|
__asm__("subl "SYMBOL_NAME_STR(init_timer_cc)",%0\n\t"
|
"sbbl "SYMBOL_NAME_STR(init_timer_cc)"+4,%1"
|
"sbbl "SYMBOL_NAME_STR(init_timer_cc)"+4,%1"
|
:"=a" (eax), "=d" (edx)
|
:"=a" (eax), "=d" (edx)
|
:"0" (eax), "1" (edx));
|
:"0" (eax), "1" (edx));
|
|
|
/*
|
/*
|
* Divide the 64-bit time with the 32-bit jiffy counter,
|
* Divide the 64-bit time with the 32-bit jiffy counter,
|
* getting the quotient in clocks.
|
* getting the quotient in clocks.
|
*
|
*
|
* Giving quotient = "average internal clocks per usec"
|
* Giving quotient = "average internal clocks per usec"
|
*/
|
*/
|
__asm__("divl %2"
|
__asm__("divl %2"
|
:"=a" (eax), "=d" (edx)
|
:"=a" (eax), "=d" (edx)
|
:"r" (tmp),
|
:"r" (tmp),
|
"0" (eax), "1" (edx));
|
"0" (eax), "1" (edx));
|
|
|
edx = 1000020/HZ;
|
edx = 1000020/HZ;
|
tmp = eax;
|
tmp = eax;
|
eax = 0;
|
eax = 0;
|
|
|
__asm__("divl %2"
|
__asm__("divl %2"
|
:"=a" (eax), "=d" (edx)
|
:"=a" (eax), "=d" (edx)
|
:"r" (tmp),
|
:"r" (tmp),
|
"0" (eax), "1" (edx));
|
"0" (eax), "1" (edx));
|
cached_quotient = eax;
|
cached_quotient = eax;
|
quotient = eax;
|
quotient = eax;
|
}
|
}
|
|
|
/* Read the time counter */
|
/* Read the time counter */
|
__asm__(".byte 0x0f,0x31"
|
__asm__(".byte 0x0f,0x31"
|
:"=a" (eax), "=d" (edx));
|
:"=a" (eax), "=d" (edx));
|
|
|
/* .. relative to previous jiffy (32 bits is enough) */
|
/* .. relative to previous jiffy (32 bits is enough) */
|
edx = 0;
|
edx = 0;
|
eax -= low_timer;
|
eax -= low_timer;
|
|
|
/*
|
/*
|
* Time offset = (1000020/HZ * time_low) / quotient.
|
* Time offset = (1000020/HZ * time_low) / quotient.
|
*/
|
*/
|
|
|
__asm__("mull %2"
|
__asm__("mull %2"
|
:"=a" (eax), "=d" (edx)
|
:"=a" (eax), "=d" (edx)
|
:"r" (quotient),
|
:"r" (quotient),
|
"0" (eax), "1" (edx));
|
"0" (eax), "1" (edx));
|
|
|
/*
|
/*
|
* Due to rounding errors (and jiffies inconsistencies),
|
* Due to rounding errors (and jiffies inconsistencies),
|
* we need to check the result so that we'll get a timer
|
* we need to check the result so that we'll get a timer
|
* that is monotonic.
|
* that is monotonic.
|
*/
|
*/
|
if (edx >= 1000020/HZ)
|
if (edx >= 1000020/HZ)
|
edx = 1000020/HZ-1;
|
edx = 1000020/HZ-1;
|
|
|
eax = edx + missing_time;
|
eax = edx + missing_time;
|
return eax;
|
return eax;
|
}
|
}
|
#endif
|
#endif
|
|
|
/* This function must be called with interrupts disabled
|
/* This function must be called with interrupts disabled
|
* It was inspired by Steve McCanne's microtime-i386 for BSD. -- jrs
|
* It was inspired by Steve McCanne's microtime-i386 for BSD. -- jrs
|
*
|
*
|
* However, the pc-audio speaker driver changes the divisor so that
|
* However, the pc-audio speaker driver changes the divisor so that
|
* it gets interrupted rather more often - it loads 64 into the
|
* it gets interrupted rather more often - it loads 64 into the
|
* counter rather than 11932! This has an adverse impact on
|
* counter rather than 11932! This has an adverse impact on
|
* do_gettimeoffset() -- it stops working! What is also not
|
* do_gettimeoffset() -- it stops working! What is also not
|
* good is that the interval that our timer function gets called
|
* good is that the interval that our timer function gets called
|
* is no longer 10.0002 ms, but 9.9767 ms. To get around this
|
* is no longer 10.0002 ms, but 9.9767 ms. To get around this
|
* would require using a different timing source. Maybe someone
|
* would require using a different timing source. Maybe someone
|
* could use the RTC - I know that this can interrupt at frequencies
|
* could use the RTC - I know that this can interrupt at frequencies
|
* ranging from 8192Hz to 2Hz. If I had the energy, I'd somehow fix
|
* ranging from 8192Hz to 2Hz. If I had the energy, I'd somehow fix
|
* it so that at startup, the timer code in sched.c would select
|
* it so that at startup, the timer code in sched.c would select
|
* using either the RTC or the 8253 timer. The decision would be
|
* using either the RTC or the 8253 timer. The decision would be
|
* based on whether there was any other device around that needed
|
* based on whether there was any other device around that needed
|
* to trample on the 8253. I'd set up the RTC to interrupt at 1024 Hz,
|
* to trample on the 8253. I'd set up the RTC to interrupt at 1024 Hz,
|
* and then do some jiggery to have a version of do_timer that
|
* and then do some jiggery to have a version of do_timer that
|
* advanced the clock by 1/1024 s. Every time that reached over 1/100
|
* advanced the clock by 1/1024 s. Every time that reached over 1/100
|
* of a second, then do all the old code. If the time was kept correct
|
* of a second, then do all the old code. If the time was kept correct
|
* then do_gettimeoffset could just return 0 - there is no low order
|
* then do_gettimeoffset could just return 0 - there is no low order
|
* divider that can be accessed.
|
* divider that can be accessed.
|
*
|
*
|
* Ideally, you would be able to use the RTC for the speaker driver,
|
* Ideally, you would be able to use the RTC for the speaker driver,
|
* but it appears that the speaker driver really needs interrupt more
|
* but it appears that the speaker driver really needs interrupt more
|
* often than every 120 us or so.
|
* often than every 120 us or so.
|
*
|
*
|
* Anyway, this needs more thought.... pjsg (1993-08-28)
|
* Anyway, this needs more thought.... pjsg (1993-08-28)
|
*
|
*
|
* If you are really that interested, you should be reading
|
* If you are really that interested, you should be reading
|
* comp.protocols.time.ntp!
|
* comp.protocols.time.ntp!
|
*/
|
*/
|
|
|
#define TICK_SIZE tick
|
#define TICK_SIZE tick
|
|
|
static unsigned long do_slow_gettimeoffset(void)
|
static unsigned long do_slow_gettimeoffset(void)
|
{
|
{
|
int count;
|
int count;
|
static int count_p = 0;
|
static int count_p = 0;
|
unsigned long offset = 0;
|
unsigned long offset = 0;
|
static unsigned long jiffies_p = 0;
|
static unsigned long jiffies_p = 0;
|
|
|
/*
|
/*
|
* cache volatile jiffies temporarily; we have IRQs turned off.
|
* cache volatile jiffies temporarily; we have IRQs turned off.
|
*/
|
*/
|
unsigned long jiffies_t;
|
unsigned long jiffies_t;
|
|
|
/* timer count may underflow right here */
|
/* timer count may underflow right here */
|
outb_p(0x00, 0x43); /* latch the count ASAP */
|
outb_p(0x00, 0x43); /* latch the count ASAP */
|
count = inb_p(0x40); /* read the latched count */
|
count = inb_p(0x40); /* read the latched count */
|
count |= inb(0x40) << 8;
|
count |= inb(0x40) << 8;
|
|
|
jiffies_t = jiffies;
|
jiffies_t = jiffies;
|
|
|
/*
|
/*
|
* avoiding timer inconsistencies (they are rare, but they happen)...
|
* avoiding timer inconsistencies (they are rare, but they happen)...
|
* there are three kinds of problems that must be avoided here:
|
* there are three kinds of problems that must be avoided here:
|
* 1. the timer counter underflows
|
* 1. the timer counter underflows
|
* 2. hardware problem with the timer, not giving us continuous time,
|
* 2. hardware problem with the timer, not giving us continuous time,
|
* the counter does small "jumps" upwards on some Pentium systems,
|
* the counter does small "jumps" upwards on some Pentium systems,
|
* thus causes time warps
|
* thus causes time warps
|
* 3. we are after the timer interrupt, but the bottom half handler
|
* 3. we are after the timer interrupt, but the bottom half handler
|
* hasn't executed yet.
|
* hasn't executed yet.
|
*/
|
*/
|
if( count > count_p ) {
|
if( count > count_p ) {
|
if( jiffies_t == jiffies_p ) {
|
if( jiffies_t == jiffies_p ) {
|
if( count > LATCH-LATCH/100 )
|
if( count > LATCH-LATCH/100 )
|
offset = TICK_SIZE;
|
offset = TICK_SIZE;
|
else
|
else
|
/*
|
/*
|
* argh, the timer is bugging we cant do nothing
|
* argh, the timer is bugging we cant do nothing
|
* but to give the previous clock value.
|
* but to give the previous clock value.
|
*/
|
*/
|
count = count_p;
|
count = count_p;
|
} else {
|
} else {
|
if( test_bit(TIMER_BH, &bh_active) ) {
|
if( test_bit(TIMER_BH, &bh_active) ) {
|
/*
|
/*
|
* we have detected a counter underflow.
|
* we have detected a counter underflow.
|
*/
|
*/
|
offset = TICK_SIZE;
|
offset = TICK_SIZE;
|
count_p = count;
|
count_p = count;
|
} else {
|
} else {
|
count_p = count;
|
count_p = count;
|
jiffies_p = jiffies_t;
|
jiffies_p = jiffies_t;
|
}
|
}
|
}
|
}
|
} else {
|
} else {
|
count_p = count;
|
count_p = count;
|
jiffies_p = jiffies_t;
|
jiffies_p = jiffies_t;
|
}
|
}
|
|
|
|
|
count = ((LATCH-1) - count) * TICK_SIZE;
|
count = ((LATCH-1) - count) * TICK_SIZE;
|
count = (count + LATCH/2) / LATCH;
|
count = (count + LATCH/2) / LATCH;
|
|
|
return offset + count;
|
return offset + count;
|
}
|
}
|
|
|
static unsigned long (*do_gettimeoffset)(void) = do_slow_gettimeoffset;
|
static unsigned long (*do_gettimeoffset)(void) = do_slow_gettimeoffset;
|
|
|
/*
|
/*
|
* This version of gettimeofday has near microsecond resolution.
|
* This version of gettimeofday has near microsecond resolution.
|
*/
|
*/
|
void do_gettimeofday(struct timeval *tv)
|
void do_gettimeofday(struct timeval *tv)
|
{
|
{
|
unsigned long flags;
|
unsigned long flags;
|
|
|
save_flags(flags);
|
save_flags(flags);
|
cli();
|
cli();
|
*tv = xtime;
|
*tv = xtime;
|
tv->tv_usec += do_gettimeoffset();
|
tv->tv_usec += do_gettimeoffset();
|
if (tv->tv_usec >= 1000000) {
|
if (tv->tv_usec >= 1000000) {
|
tv->tv_usec -= 1000000;
|
tv->tv_usec -= 1000000;
|
tv->tv_sec++;
|
tv->tv_sec++;
|
}
|
}
|
restore_flags(flags);
|
restore_flags(flags);
|
}
|
}
|
|
|
void do_settimeofday(struct timeval *tv)
|
void do_settimeofday(struct timeval *tv)
|
{
|
{
|
cli();
|
cli();
|
/* This is revolting. We need to set the xtime.tv_usec
|
/* This is revolting. We need to set the xtime.tv_usec
|
* correctly. However, the value in this location is
|
* correctly. However, the value in this location is
|
* is value at the last tick.
|
* is value at the last tick.
|
* Discover what correction gettimeofday
|
* Discover what correction gettimeofday
|
* would have done, and then undo it!
|
* would have done, and then undo it!
|
*/
|
*/
|
tv->tv_usec -= do_gettimeoffset();
|
tv->tv_usec -= do_gettimeoffset();
|
|
|
if (tv->tv_usec < 0) {
|
if (tv->tv_usec < 0) {
|
tv->tv_usec += 1000000;
|
tv->tv_usec += 1000000;
|
tv->tv_sec--;
|
tv->tv_sec--;
|
}
|
}
|
|
|
xtime = *tv;
|
xtime = *tv;
|
time_adjust = 0; /* stop active adjtime() */
|
time_adjust = 0; /* stop active adjtime() */
|
time_status |= STA_UNSYNC;
|
time_status |= STA_UNSYNC;
|
time_state = TIME_ERROR; /* p. 24, (a) */
|
time_state = TIME_ERROR; /* p. 24, (a) */
|
time_maxerror = NTP_PHASE_LIMIT;
|
time_maxerror = NTP_PHASE_LIMIT;
|
time_esterror = NTP_PHASE_LIMIT;
|
time_esterror = NTP_PHASE_LIMIT;
|
sti();
|
sti();
|
}
|
}
|
|
|
|
|
/*
|
/*
|
* In order to set the CMOS clock precisely, set_rtc_mmss has to be
|
* 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
|
* called 500 ms after the second nowtime has started, because when
|
* nowtime is written into the registers of the CMOS clock, it will
|
* nowtime is written into the registers of the CMOS clock, it will
|
* jump to the next second precisely 500 ms later. Check the Motorola
|
* jump to the next second precisely 500 ms later. Check the Motorola
|
* MC146818A or Dallas DS12887 data sheet for details.
|
* MC146818A or Dallas DS12887 data sheet for details.
|
*
|
*
|
* BUG: This routine does not handle hour overflow properly; it just
|
* BUG: This routine does not handle hour overflow properly; it just
|
* sets the minutes. Usually you'll only notice that after reboot!
|
* sets the minutes. Usually you'll only notice that after reboot!
|
*/
|
*/
|
static int set_rtc_mmss(unsigned long nowtime)
|
static int set_rtc_mmss(unsigned long nowtime)
|
{
|
{
|
int retval = 0;
|
int retval = 0;
|
int real_seconds, real_minutes, cmos_minutes;
|
int real_seconds, real_minutes, cmos_minutes;
|
unsigned char save_control, save_freq_select;
|
unsigned char save_control, save_freq_select;
|
|
|
save_control = CMOS_READ(RTC_CONTROL); /* tell the clock it's being set */
|
save_control = CMOS_READ(RTC_CONTROL); /* tell the clock it's being set */
|
CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
|
CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
|
|
|
save_freq_select = CMOS_READ(RTC_FREQ_SELECT); /* stop and reset prescaler */
|
save_freq_select = CMOS_READ(RTC_FREQ_SELECT); /* stop and reset prescaler */
|
CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
|
CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
|
|
|
cmos_minutes = CMOS_READ(RTC_MINUTES);
|
cmos_minutes = CMOS_READ(RTC_MINUTES);
|
if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
|
if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
|
BCD_TO_BIN(cmos_minutes);
|
BCD_TO_BIN(cmos_minutes);
|
|
|
/*
|
/*
|
* since we're only adjusting minutes and seconds,
|
* since we're only adjusting minutes and seconds,
|
* don't interfere with hour overflow. This avoids
|
* don't interfere with hour overflow. This avoids
|
* messing with unknown time zones but requires your
|
* messing with unknown time zones but requires your
|
* RTC not to be off by more than 15 minutes
|
* RTC not to be off by more than 15 minutes
|
*/
|
*/
|
real_seconds = nowtime % 60;
|
real_seconds = nowtime % 60;
|
real_minutes = nowtime / 60;
|
real_minutes = nowtime / 60;
|
if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)
|
if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)
|
real_minutes += 30; /* correct for half hour time zone */
|
real_minutes += 30; /* correct for half hour time zone */
|
real_minutes %= 60;
|
real_minutes %= 60;
|
|
|
if (abs(real_minutes - cmos_minutes) < 30) {
|
if (abs(real_minutes - cmos_minutes) < 30) {
|
if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
|
if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
|
BIN_TO_BCD(real_seconds);
|
BIN_TO_BCD(real_seconds);
|
BIN_TO_BCD(real_minutes);
|
BIN_TO_BCD(real_minutes);
|
}
|
}
|
CMOS_WRITE(real_seconds,RTC_SECONDS);
|
CMOS_WRITE(real_seconds,RTC_SECONDS);
|
CMOS_WRITE(real_minutes,RTC_MINUTES);
|
CMOS_WRITE(real_minutes,RTC_MINUTES);
|
} else {
|
} else {
|
printk(KERN_WARNING
|
printk(KERN_WARNING
|
"set_rtc_mmss: can't update from %d to %d\n",
|
"set_rtc_mmss: can't update from %d to %d\n",
|
cmos_minutes, real_minutes);
|
cmos_minutes, real_minutes);
|
retval = -1;
|
retval = -1;
|
}
|
}
|
|
|
/* The following flags have to be released exactly in this order,
|
/* The following flags have to be released exactly in this order,
|
* otherwise the DS12887 (popular MC146818A clone with integrated
|
* otherwise the DS12887 (popular MC146818A clone with integrated
|
* battery and quartz) will not reset the oscillator and will not
|
* battery and quartz) will not reset the oscillator and will not
|
* update precisely 500 ms later. You won't find this mentioned in
|
* update precisely 500 ms later. You won't find this mentioned in
|
* the Dallas Semiconductor data sheets, but who believes data
|
* the Dallas Semiconductor data sheets, but who believes data
|
* sheets anyway ... -- Markus Kuhn
|
* sheets anyway ... -- Markus Kuhn
|
*/
|
*/
|
CMOS_WRITE(save_control, RTC_CONTROL);
|
CMOS_WRITE(save_control, RTC_CONTROL);
|
CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
|
CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
|
|
|
return retval;
|
return retval;
|
}
|
}
|
|
|
/* last time the cmos clock got updated */
|
/* last time the cmos clock got updated */
|
static long last_rtc_update = 0;
|
static long last_rtc_update = 0;
|
|
|
/*
|
/*
|
* timer_interrupt() needs to keep up the real-time clock,
|
* timer_interrupt() needs to keep up the real-time clock,
|
* as well as call the "do_timer()" routine every clocktick
|
* as well as call the "do_timer()" routine every clocktick
|
*/
|
*/
|
static inline void timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
|
static inline void timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
|
{
|
{
|
do_timer(regs);
|
do_timer(regs);
|
|
|
/*
|
/*
|
* If we have an externally synchronized Linux clock, then update
|
* If we have an externally synchronized Linux clock, then update
|
* CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
|
* 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.
|
* called as close as possible to 500 ms before the new second starts.
|
*/
|
*/
|
if ((time_status & STA_UNSYNC) == 0 &&
|
if ((time_status & STA_UNSYNC) == 0 &&
|
xtime.tv_sec > last_rtc_update + 660 &&
|
xtime.tv_sec > last_rtc_update + 660 &&
|
xtime.tv_usec > 500000 - (tick >> 1) &&
|
xtime.tv_usec > 500000 - (tick >> 1) &&
|
xtime.tv_usec < 500000 + (tick >> 1))
|
xtime.tv_usec < 500000 + (tick >> 1))
|
if (set_rtc_mmss(xtime.tv_sec) == 0)
|
if (set_rtc_mmss(xtime.tv_sec) == 0)
|
last_rtc_update = xtime.tv_sec;
|
last_rtc_update = xtime.tv_sec;
|
else
|
else
|
last_rtc_update = xtime.tv_sec - 600; /* do it again in 60 s */
|
last_rtc_update = xtime.tv_sec - 600; /* do it again in 60 s */
|
/* As we return to user mode fire off the other CPU schedulers.. this is
|
/* As we return to user mode fire off the other CPU schedulers.. this is
|
basically because we don't yet share IRQ's around. This message is
|
basically because we don't yet share IRQ's around. This message is
|
rigged to be safe on the 386 - basically it's a hack, so don't look
|
rigged to be safe on the 386 - basically it's a hack, so don't look
|
closely for now.. */
|
closely for now.. */
|
/*smp_message_pass(MSG_ALL_BUT_SELF, MSG_RESCHEDULE, 0L, 0); */
|
/*smp_message_pass(MSG_ALL_BUT_SELF, MSG_RESCHEDULE, 0L, 0); */
|
|
|
}
|
}
|
|
|
#ifndef CONFIG_APM /* cycle counter may be unreliable */
|
#ifndef CONFIG_APM /* cycle counter may be unreliable */
|
/*
|
/*
|
* This is the same as the above, except we _also_ save the current
|
* This is the same as the above, except we _also_ save the current
|
* cycle counter value at the time of the timer interrupt, so that
|
* cycle counter value at the time of the timer interrupt, so that
|
* we later on can estimate the time of day more exactly.
|
* we later on can estimate the time of day more exactly.
|
*/
|
*/
|
static void pentium_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
|
static void pentium_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
|
{
|
{
|
/* read Pentium cycle counter */
|
/* read Pentium cycle counter */
|
__asm__(".byte 0x0f,0x31"
|
__asm__(".byte 0x0f,0x31"
|
:"=a" (last_timer_cc.low),
|
:"=a" (last_timer_cc.low),
|
"=d" (last_timer_cc.high));
|
"=d" (last_timer_cc.high));
|
timer_interrupt(irq, NULL, regs);
|
timer_interrupt(irq, NULL, regs);
|
}
|
}
|
#endif
|
#endif
|
|
|
/* Converts Gregorian date to seconds since 1970-01-01 00:00:00.
|
/* Converts Gregorian date to seconds since 1970-01-01 00:00:00.
|
* Assumes input in normal date format, i.e. 1980-12-31 23:59:59
|
* Assumes input in normal date format, i.e. 1980-12-31 23:59:59
|
* => year=1980, mon=12, day=31, hour=23, min=59, sec=59.
|
* => year=1980, mon=12, day=31, hour=23, min=59, sec=59.
|
*
|
*
|
* [For the Julian calendar (which was used in Russia before 1917,
|
* [For the Julian calendar (which was used in Russia before 1917,
|
* Britain & colonies before 1752, anywhere else before 1582,
|
* Britain & colonies before 1752, anywhere else before 1582,
|
* and is still in use by some communities) leave out the
|
* and is still in use by some communities) leave out the
|
* -year/100+year/400 terms, and add 10.]
|
* -year/100+year/400 terms, and add 10.]
|
*
|
*
|
* This algorithm was first published by Gauss (I think).
|
* This algorithm was first published by Gauss (I think).
|
*
|
*
|
* WARNING: this function will overflow on 2106-02-07 06:28:16 on
|
* WARNING: this function will overflow on 2106-02-07 06:28:16 on
|
* machines were long is 32-bit! (However, as time_t is signed, we
|
* machines were long is 32-bit! (However, as time_t is signed, we
|
* will already get problems at other places on 2038-01-19 03:14:08)
|
* will already get problems at other places on 2038-01-19 03:14:08)
|
*/
|
*/
|
static inline unsigned long mktime(unsigned int year, unsigned int mon,
|
static inline unsigned long mktime(unsigned int year, unsigned int mon,
|
unsigned int day, unsigned int hour,
|
unsigned int day, unsigned int hour,
|
unsigned int min, unsigned int sec)
|
unsigned int min, unsigned int sec)
|
{
|
{
|
if (0 >= (int) (mon -= 2)) { /* 1..12 -> 11,12,1..10 */
|
if (0 >= (int) (mon -= 2)) { /* 1..12 -> 11,12,1..10 */
|
mon += 12; /* Puts Feb last since it has leap day */
|
mon += 12; /* Puts Feb last since it has leap day */
|
year -= 1;
|
year -= 1;
|
}
|
}
|
return (((
|
return (((
|
(unsigned long)(year/4 - year/100 + year/400 + 367*mon/12 + day) +
|
(unsigned long)(year/4 - year/100 + year/400 + 367*mon/12 + day) +
|
year*365 - 719499
|
year*365 - 719499
|
)*24 + hour /* now have hours */
|
)*24 + hour /* now have hours */
|
)*60 + min /* now have minutes */
|
)*60 + min /* now have minutes */
|
)*60 + sec; /* finally seconds */
|
)*60 + sec; /* finally seconds */
|
}
|
}
|
|
|
/* not static: needed by APM */
|
/* not static: needed by APM */
|
unsigned long get_cmos_time(void)
|
unsigned long get_cmos_time(void)
|
{
|
{
|
unsigned int year, mon, day, hour, min, sec;
|
unsigned int year, mon, day, hour, min, sec;
|
int i;
|
int i;
|
|
|
/* The Linux interpretation of the CMOS clock register contents:
|
/* The Linux interpretation of the CMOS clock register contents:
|
* When the Update-In-Progress (UIP) flag goes from 1 to 0, the
|
* When the Update-In-Progress (UIP) flag goes from 1 to 0, the
|
* RTC registers show the second which has precisely just started.
|
* RTC registers show the second which has precisely just started.
|
* Let's hope other operating systems interpret the RTC the same way.
|
* Let's hope other operating systems interpret the RTC the same way.
|
*/
|
*/
|
/* read RTC exactly on falling edge of update flag */
|
/* read RTC exactly on falling edge of update flag */
|
for (i = 0 ; i < 1000000 ; i++) /* may take up to 1 second... */
|
for (i = 0 ; i < 1000000 ; i++) /* may take up to 1 second... */
|
if (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP)
|
if (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP)
|
break;
|
break;
|
for (i = 0 ; i < 1000000 ; i++) /* must try at least 2.228 ms */
|
for (i = 0 ; i < 1000000 ; i++) /* must try at least 2.228 ms */
|
if (!(CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP))
|
if (!(CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP))
|
break;
|
break;
|
do { /* Isn't this overkill ? UIP above should guarantee consistency */
|
do { /* Isn't this overkill ? UIP above should guarantee consistency */
|
sec = CMOS_READ(RTC_SECONDS);
|
sec = CMOS_READ(RTC_SECONDS);
|
min = CMOS_READ(RTC_MINUTES);
|
min = CMOS_READ(RTC_MINUTES);
|
hour = CMOS_READ(RTC_HOURS);
|
hour = CMOS_READ(RTC_HOURS);
|
day = CMOS_READ(RTC_DAY_OF_MONTH);
|
day = CMOS_READ(RTC_DAY_OF_MONTH);
|
mon = CMOS_READ(RTC_MONTH);
|
mon = CMOS_READ(RTC_MONTH);
|
year = CMOS_READ(RTC_YEAR);
|
year = CMOS_READ(RTC_YEAR);
|
} while (sec != CMOS_READ(RTC_SECONDS));
|
} while (sec != CMOS_READ(RTC_SECONDS));
|
if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
|
if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
|
{
|
{
|
BCD_TO_BIN(sec);
|
BCD_TO_BIN(sec);
|
BCD_TO_BIN(min);
|
BCD_TO_BIN(min);
|
BCD_TO_BIN(hour);
|
BCD_TO_BIN(hour);
|
BCD_TO_BIN(day);
|
BCD_TO_BIN(day);
|
BCD_TO_BIN(mon);
|
BCD_TO_BIN(mon);
|
BCD_TO_BIN(year);
|
BCD_TO_BIN(year);
|
}
|
}
|
if ((year += 1900) < 1970)
|
if ((year += 1900) < 1970)
|
year += 100;
|
year += 100;
|
return mktime(year, mon, day, hour, min, sec);
|
return mktime(year, mon, day, hour, min, sec);
|
}
|
}
|
|
|
static struct irqaction irq0 = { timer_interrupt, 0, 0, "timer", NULL, NULL};
|
static struct irqaction irq0 = { timer_interrupt, 0, 0, "timer", NULL, NULL};
|
|
|
void time_init(void)
|
void time_init(void)
|
{
|
{
|
xtime.tv_sec = get_cmos_time();
|
xtime.tv_sec = get_cmos_time();
|
xtime.tv_usec = 0;
|
xtime.tv_usec = 0;
|
|
|
/* If we have the CPU hardware time counters, use them */
|
/* If we have the CPU hardware time counters, use them */
|
#ifndef CONFIG_APM
|
#ifndef CONFIG_APM
|
/* Don't use them if a suspend/resume could
|
/* Don't use them if a suspend/resume could
|
corrupt the timer value. This problem
|
corrupt the timer value. This problem
|
needs more debugging. */
|
needs more debugging. */
|
if (x86_capability & 16)
|
if (x86_capability & 16)
|
if (strncmp(x86_vendor_id, "Cyrix", 5) != 0) {
|
if (strncmp(x86_vendor_id, "Cyrix", 5) != 0) {
|
do_gettimeoffset = do_fast_gettimeoffset;
|
do_gettimeoffset = do_fast_gettimeoffset;
|
|
|
if( strcmp( x86_vendor_id, "AuthenticAMD" ) == 0 ) {
|
if( strcmp( x86_vendor_id, "AuthenticAMD" ) == 0 ) {
|
if( x86 == 5 ) {
|
if( x86 == 5 ) {
|
if( x86_model == 0 ) {
|
if( x86_model == 0 ) {
|
/* turn on cycle counters during power down */
|
/* turn on cycle counters during power down */
|
__asm__ __volatile__ (" movl $0x83, %%ecx \n \
|
__asm__ __volatile__ (" movl $0x83, %%ecx \n \
|
.byte 0x0f,0x32 \n \
|
.byte 0x0f,0x32 \n \
|
orl $1,%%eax \n \
|
orl $1,%%eax \n \
|
.byte 0x0f,0x30 \n "
|
.byte 0x0f,0x30 \n "
|
: : : "ax", "cx", "dx" );
|
: : : "ax", "cx", "dx" );
|
udelay(500);
|
udelay(500);
|
}
|
}
|
}
|
}
|
}
|
}
|
|
|
/* read Pentium cycle counter */
|
/* read Pentium cycle counter */
|
__asm__(".byte 0x0f,0x31"
|
__asm__(".byte 0x0f,0x31"
|
:"=a" (init_timer_cc.low),
|
:"=a" (init_timer_cc.low),
|
"=d" (init_timer_cc.high));
|
"=d" (init_timer_cc.high));
|
irq0.handler = pentium_timer_interrupt;
|
irq0.handler = pentium_timer_interrupt;
|
}
|
}
|
#endif
|
#endif
|
setup_x86_irq(0, &irq0);
|
setup_x86_irq(0, &irq0);
|
}
|
}
|
|
|
