OpenSDV
/
original_kernel
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
original_kernel/arch/i386/kernel/time.c

494 lines
12 KiB
C
Raw Blame History

/*
* linux/arch/i386/kernel/time.c
*
* Copyright (C) 1991, 1992, 1995 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
* 1996-05-03 Ingo Molnar
* fixed time warps in do_[slow|fast]_gettimeoffset()
* 1997-09-10 Updated NTP code according to technical memorandum Jan '96
* "A Kernel Model for Precision Timekeeping" by Dave Mills
* 1998-09-05 (Various)
* More robust do_fast_gettimeoffset() algorithm implemented
* (works with APM, Cyrix 6x86MX and Centaur C6),
* monotonic gettimeofday() with fast_get_timeoffset(),
* drift-proof precision TSC calibration on boot
* (C. Scott Ananian <cananian@alumni.princeton.edu>, Andrew D.
* Balsa <andrebalsa@altern.org>, Philip Gladstone <philip@raptor.com>;
* ported from 2.0.35 Jumbo-9 by Michael Krause <m.krause@tu-harburg.de>).
* 1998-12-16 Andrea Arcangeli
* Fixed Jumbo-9 code in 2.1.131: do_gettimeofday was missing 1 jiffy
* because was not accounting lost_ticks.
* 1998-12-24 Copyright (C) 1998 Andrea Arcangeli
* Fixed a xtime SMP race (we need the xtime_lock rw spinlock to
* serialize accesses to xtime/lost_ticks).
*/
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/param.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/time.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/smp.h>
#include <linux/module.h>
#include <linux/sysdev.h>
#include <linux/bcd.h>
#include <linux/efi.h>
#include <linux/mca.h>
#include <asm/io.h>
#include <asm/smp.h>
#include <asm/irq.h>
#include <asm/msr.h>
#include <asm/delay.h>
#include <asm/mpspec.h>
#include <asm/uaccess.h>
#include <asm/processor.h>
#include <asm/timer.h>
#include "mach_time.h"
#include <linux/timex.h>
#include <linux/config.h>
#include <asm/hpet.h>
#include <asm/arch_hooks.h>
#include "io_ports.h"
#include <asm/i8259.h>
int pit_latch_buggy; /* extern */
#include "do_timer.h"
u64 jiffies_64 = INITIAL_JIFFIES;
EXPORT_SYMBOL(jiffies_64);
unsigned int cpu_khz; /* Detected as we calibrate the TSC */
EXPORT_SYMBOL(cpu_khz);
extern unsigned long wall_jiffies;
DEFINE_SPINLOCK(rtc_lock);
EXPORT_SYMBOL(rtc_lock);
#include <asm/i8253.h>
DEFINE_SPINLOCK(i8253_lock);
EXPORT_SYMBOL(i8253_lock);
struct timer_opts *cur_timer __read_mostly = &timer_none;
/*
* This is a special lock that is owned by the CPU and holds the index
* register we are working with. It is required for NMI access to the
* CMOS/RTC registers. See include/asm-i386/mc146818rtc.h for details.
*/
volatile unsigned long cmos_lock = 0;
EXPORT_SYMBOL(cmos_lock);
/* Routines for accessing the CMOS RAM/RTC. */
unsigned char rtc_cmos_read(unsigned char addr)
{
unsigned char val;
lock_cmos_prefix(addr);
outb_p(addr, RTC_PORT(0));
val = inb_p(RTC_PORT(1));
lock_cmos_suffix(addr);
return val;
}
EXPORT_SYMBOL(rtc_cmos_read);
void rtc_cmos_write(unsigned char val, unsigned char addr)
{
lock_cmos_prefix(addr);
outb_p(addr, RTC_PORT(0));
outb_p(val, RTC_PORT(1));
lock_cmos_suffix(addr);
}
EXPORT_SYMBOL(rtc_cmos_write);
/*
* This version of gettimeofday has microsecond resolution
* and better than microsecond precision on fast x86 machines with TSC.
*/
void do_gettimeofday(struct timeval *tv)
{
unsigned long seq;
unsigned long usec, sec;
unsigned long max_ntp_tick;
do {
unsigned long lost;
seq = read_seqbegin(&xtime_lock);
usec = cur_timer->get_offset();
lost = jiffies - wall_jiffies;
/*
* If time_adjust is negative then NTP is slowing the clock
* so make sure not to go into next possible interval.
* Better to lose some accuracy than have time go backwards..
*/
if (unlikely(time_adjust < 0)) {
max_ntp_tick = (USEC_PER_SEC / HZ) - tickadj;
usec = min(usec, max_ntp_tick);
if (lost)
usec += lost * max_ntp_tick;
}
else if (unlikely(lost))
usec += lost * (USEC_PER_SEC / HZ);
sec = xtime.tv_sec;
usec += (xtime.tv_nsec / 1000);
} while (read_seqretry(&xtime_lock, seq));
while (usec >= 1000000) {
usec -= 1000000;
sec++;
}
tv->tv_sec = sec;
tv->tv_usec = usec;
}
EXPORT_SYMBOL(do_gettimeofday);
int do_settimeofday(struct timespec *tv)
{
time_t wtm_sec, sec = tv->tv_sec;
long wtm_nsec, nsec = tv->tv_nsec;
if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
return -EINVAL;
write_seqlock_irq(&xtime_lock);
/*
* This is revolting. We need to set "xtime" correctly. However, the
* value in this location is the value at the most recent update of
* wall time. Discover what correction gettimeofday() would have
* made, and then undo it!
*/
nsec -= cur_timer->get_offset() * NSEC_PER_USEC;
nsec -= (jiffies - wall_jiffies) * TICK_NSEC;
wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
set_normalized_timespec(&xtime, sec, nsec);
set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
time_adjust = 0; /* stop active adjtime() */
time_status |= STA_UNSYNC;
time_maxerror = NTP_PHASE_LIMIT;
time_esterror = NTP_PHASE_LIMIT;
write_sequnlock_irq(&xtime_lock);
clock_was_set();
return 0;
}
EXPORT_SYMBOL(do_settimeofday);
static int set_rtc_mmss(unsigned long nowtime)
{
int retval;
WARN_ON(irqs_disabled());
/* gets recalled with irq locally disabled */
spin_lock_irq(&rtc_lock);
if (efi_enabled)
retval = efi_set_rtc_mmss(nowtime);
else
retval = mach_set_rtc_mmss(nowtime);
spin_unlock_irq(&rtc_lock);
return retval;
}
int timer_ack;
/* monotonic_clock(): returns # of nanoseconds passed since time_init()
* Note: This function is required to return accurate
* time even in the absence of multiple timer ticks.
*/
unsigned long long monotonic_clock(void)
{
return cur_timer->monotonic_clock();
}
EXPORT_SYMBOL(monotonic_clock);
#if defined(CONFIG_SMP) && defined(CONFIG_FRAME_POINTER)
unsigned long profile_pc(struct pt_regs *regs)
{
unsigned long pc = instruction_pointer(regs);
if (in_lock_functions(pc))
return *(unsigned long *)(regs->ebp + 4);
return pc;
}
EXPORT_SYMBOL(profile_pc);
#endif
/*
* timer_interrupt() needs to keep up the real-time clock,
* as well as call the "do_timer()" routine every clocktick
*/
static inline void do_timer_interrupt(int irq, void *dev_id,
struct pt_regs *regs)
{
#ifdef CONFIG_X86_IO_APIC
if (timer_ack) {
/*
* Subtle, when I/O APICs are used we have to ack timer IRQ
* manually to reset the IRR bit for do_slow_gettimeoffset().
* This will also deassert NMI lines for the watchdog if run
* on an 82489DX-based system.
*/
spin_lock(&i8259A_lock);
outb(0x0c, PIC_MASTER_OCW3);
/* Ack the IRQ; AEOI will end it automatically. */
inb(PIC_MASTER_POLL);
spin_unlock(&i8259A_lock);
}
#endif
do_timer_interrupt_hook(regs);
if (MCA_bus) {
/* The PS/2 uses level-triggered interrupts. You can't
turn them off, nor would you want to (any attempt to
enable edge-triggered interrupts usually gets intercepted by a
special hardware circuit). Hence we have to acknowledge
the timer interrupt. Through some incredibly stupid
design idea, the reset for IRQ 0 is done by setting the
high bit of the PPI port B (0x61). Note that some PS/2s,
notably the 55SX, work fine if this is removed. */
irq = inb_p( 0x61 ); /* read the current state */
outb_p( irq|0x80, 0x61 ); /* reset the IRQ */
}
}
/*
* This is the same as the above, except we _also_ save the current
* Time Stamp Counter value at the time of the timer interrupt, so that
* we later on can estimate the time of day more exactly.
*/
irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
/*
* Here we are in the timer irq handler. We just have irqs locally
* disabled but we don't know if the timer_bh is running on the other
* CPU. We need to avoid to SMP race with it. NOTE: we don' t need
* the irq version of write_lock because as just said we have irq
* locally disabled. -arca
*/
write_seqlock(&xtime_lock);
cur_timer->mark_offset();
do_timer_interrupt(irq, NULL, regs);
write_sequnlock(&xtime_lock);
return IRQ_HANDLED;
}
/* not static: needed by APM */
unsigned long get_cmos_time(void)
{
unsigned long retval;
spin_lock(&rtc_lock);
if (efi_enabled)
retval = efi_get_time();
else
retval = mach_get_cmos_time();
spin_unlock(&rtc_lock);
return retval;
}
EXPORT_SYMBOL(get_cmos_time);
static void sync_cmos_clock(unsigned long dummy);
static struct timer_list sync_cmos_timer =
TIMER_INITIALIZER(sync_cmos_clock, 0, 0);
static void sync_cmos_clock(unsigned long dummy)
{
struct timeval now, next;
int fail = 1;
/*
* 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.
* This code is run on a timer. If the clock is set, that timer
* may not expire at the correct time. Thus, we adjust...
*/
if ((time_status & STA_UNSYNC) != 0)
/*
* Not synced, exit, do not restart a timer (if one is
* running, let it run out).
*/
return;
do_gettimeofday(&now);
if (now.tv_usec >= USEC_AFTER - ((unsigned) TICK_SIZE) / 2 &&
now.tv_usec <= USEC_BEFORE + ((unsigned) TICK_SIZE) / 2)
fail = set_rtc_mmss(now.tv_sec);
next.tv_usec = USEC_AFTER - now.tv_usec;
if (next.tv_usec <= 0)
next.tv_usec += USEC_PER_SEC;
if (!fail)
next.tv_sec = 659;
else
next.tv_sec = 0;
if (next.tv_usec >= USEC_PER_SEC) {
next.tv_sec++;
next.tv_usec -= USEC_PER_SEC;
}
mod_timer(&sync_cmos_timer, jiffies + timeval_to_jiffies(&next));
}
void notify_arch_cmos_timer(void)
{
mod_timer(&sync_cmos_timer, jiffies + 1);
}
static long clock_cmos_diff, sleep_start;
static struct timer_opts *last_timer;
static int timer_suspend(struct sys_device *dev, pm_message_t state)
{
/*
* Estimate time zone so that set_time can update the clock
*/
clock_cmos_diff = -get_cmos_time();
clock_cmos_diff += get_seconds();
sleep_start = get_cmos_time();
last_timer = cur_timer;
cur_timer = &timer_none;
if (last_timer->suspend)
last_timer->suspend(state);
return 0;
}
static int timer_resume(struct sys_device *dev)
{
unsigned long flags;
unsigned long sec;
unsigned long sleep_length;
#ifdef CONFIG_HPET_TIMER
if (is_hpet_enabled())
hpet_reenable();
#endif
setup_pit_timer();
sec = get_cmos_time() + clock_cmos_diff;
sleep_length = (get_cmos_time() - sleep_start) * HZ;
write_seqlock_irqsave(&xtime_lock, flags);
xtime.tv_sec = sec;
xtime.tv_nsec = 0;
write_sequnlock_irqrestore(&xtime_lock, flags);
jiffies += sleep_length;
wall_jiffies += sleep_length;
if (last_timer->resume)
last_timer->resume();
cur_timer = last_timer;
last_timer = NULL;
return 0;
}
static struct sysdev_class timer_sysclass = {
.resume = timer_resume,
.suspend = timer_suspend,
set_kset_name("timer"),
};
/* XXX this driverfs stuff should probably go elsewhere later -john */
static struct sys_device device_timer = {
.id = 0,
.cls = &timer_sysclass,
};
static int time_init_device(void)
{
int error = sysdev_class_register(&timer_sysclass);
if (!error)
error = sysdev_register(&device_timer);
return error;
}
device_initcall(time_init_device);
#ifdef CONFIG_HPET_TIMER
extern void (*late_time_init)(void);
/* Duplicate of time_init() below, with hpet_enable part added */
static void __init hpet_time_init(void)
{
xtime.tv_sec = get_cmos_time();
xtime.tv_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ);
set_normalized_timespec(&wall_to_monotonic,
-xtime.tv_sec, -xtime.tv_nsec);
if ((hpet_enable() >= 0) && hpet_use_timer) {
printk("Using HPET for base-timer\n");
}
cur_timer = select_timer();
printk(KERN_INFO "Using %s for high-res timesource\n",cur_timer->name);
time_init_hook();
}
#endif
void __init time_init(void)
{
#ifdef CONFIG_HPET_TIMER
if (is_hpet_capable()) {
/*
* HPET initialization needs to do memory-mapped io. So, let
* us do a late initialization after mem_init().
*/
late_time_init = hpet_time_init;
return;
}
#endif
xtime.tv_sec = get_cmos_time();
xtime.tv_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ);
set_normalized_timespec(&wall_to_monotonic,
-xtime.tv_sec, -xtime.tv_nsec);
cur_timer = select_timer();
printk(KERN_INFO "Using %s for high-res timesource\n",cur_timer->name);
time_init_hook();
}
Reference in New Issue View Git Blame Copy Permalink