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yaml
---
r: 135745
b: refs/heads/master
c: 53bbfa9
h: refs/heads/master
i:
  135743: 1416787
v: v3
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Ingo Molnar committed Feb 25, 2009
1 parent ef728cf commit 701ca34
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Showing 2 changed files with 82 additions and 49 deletions.
2 changes: 1 addition & 1 deletion [refs]
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---
refs/heads/master: fdcedf7b75808dd72c3cc0b931be11b04d75c60a
refs/heads/master: 53bbfa9e9437e70b322368e82c723112d690e304
129 changes: 81 additions & 48 deletions trunk/kernel/time/ntp.c
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Original file line number Diff line number Diff line change
@@ -1,53 +1,81 @@
/*
* linux/kernel/time/ntp.c
*
* NTP state machine interfaces and logic.
*
* This code was mainly moved from kernel/timer.c and kernel/time.c
* Please see those files for relevant copyright info and historical
* changelogs.
*/

#include <linux/mm.h>
#include <linux/time.h>
#include <linux/timex.h>
#include <linux/jiffies.h>
#include <linux/hrtimer.h>
#include <linux/capability.h>
#include <linux/math64.h>
#include <linux/clocksource.h>
#include <linux/workqueue.h>
#include <asm/timex.h>
#include <linux/hrtimer.h>
#include <linux/jiffies.h>
#include <linux/math64.h>
#include <linux/timex.h>
#include <linux/time.h>
#include <linux/mm.h>

/*
* Timekeeping variables
* NTP timekeeping variables:
*/
unsigned long tick_usec = TICK_USEC; /* USER_HZ period (usec) */
unsigned long tick_nsec; /* ACTHZ period (nsec) */
u64 tick_length;
static u64 tick_length_base;

static struct hrtimer leap_timer;
/* USER_HZ period (usecs): */
unsigned long tick_usec = TICK_USEC;

/* ACTHZ period (nsecs): */
unsigned long tick_nsec;

#define MAX_TICKADJ 500 /* microsecs */
#define MAX_TICKADJ_SCALED (((u64)(MAX_TICKADJ * NSEC_PER_USEC) << \
NTP_SCALE_SHIFT) / NTP_INTERVAL_FREQ)
u64 tick_length;
static u64 tick_length_base;

static struct hrtimer leap_timer;

#define MAX_TICKADJ 500 /* usecs */
#define MAX_TICKADJ_SCALED \
(((u64)(MAX_TICKADJ * NSEC_PER_USEC) << NTP_SCALE_SHIFT) / NTP_INTERVAL_FREQ)

/*
* phase-lock loop variables
*/
/* TIME_ERROR prevents overwriting the CMOS clock */
static int time_state = TIME_OK; /* clock synchronization status */
int time_status = STA_UNSYNC; /* clock status bits */
static long time_tai; /* TAI offset (s) */
static s64 time_offset; /* time adjustment (ns) */
static long time_constant = 2; /* pll time constant */
long time_maxerror = NTP_PHASE_LIMIT; /* maximum error (us) */
long time_esterror = NTP_PHASE_LIMIT; /* estimated error (us) */
static s64 time_freq; /* frequency offset (scaled ns/s)*/
static long time_reftime; /* time at last adjustment (s) */
long time_adjust;
static long ntp_tick_adj;

/*
* clock synchronization status
*
* (TIME_ERROR prevents overwriting the CMOS clock)
*/
static int time_state = TIME_OK;

/* clock status bits: */
int time_status = STA_UNSYNC;

/* TAI offset (secs): */
static long time_tai;

/* time adjustment (nsecs): */
static s64 time_offset;

/* pll time constant: */
static long time_constant = 2;

/* maximum error (usecs): */
long time_maxerror = NTP_PHASE_LIMIT;

/* estimated error (usecs): */
long time_esterror = NTP_PHASE_LIMIT;

/* frequency offset (scaled nsecs/secs): */
static s64 time_freq;

/* time at last adjustment (secs): */
static long time_reftime;

long time_adjust;

static long ntp_tick_adj;

/*
* NTP methods:
*/

static void ntp_update_frequency(void)
{
Expand Down Expand Up @@ -118,15 +146,15 @@ static void ntp_update_offset(long offset)
*/
void ntp_clear(void)
{
time_adjust = 0; /* stop active adjtime() */
time_status |= STA_UNSYNC;
time_maxerror = NTP_PHASE_LIMIT;
time_esterror = NTP_PHASE_LIMIT;
time_adjust = 0; /* stop active adjtime() */
time_status |= STA_UNSYNC;
time_maxerror = NTP_PHASE_LIMIT;
time_esterror = NTP_PHASE_LIMIT;

ntp_update_frequency();

tick_length = tick_length_base;
time_offset = 0;
tick_length = tick_length_base;
time_offset = 0;
}

/*
Expand All @@ -147,8 +175,8 @@ static enum hrtimer_restart ntp_leap_second(struct hrtimer *timer)
xtime.tv_sec--;
wall_to_monotonic.tv_sec++;
time_state = TIME_OOP;
printk(KERN_NOTICE "Clock: "
"inserting leap second 23:59:60 UTC\n");
printk(KERN_NOTICE
"Clock: inserting leap second 23:59:60 UTC\n");
hrtimer_add_expires_ns(&leap_timer, NSEC_PER_SEC);
res = HRTIMER_RESTART;
break;
Expand All @@ -157,8 +185,8 @@ static enum hrtimer_restart ntp_leap_second(struct hrtimer *timer)
time_tai--;
wall_to_monotonic.tv_sec--;
time_state = TIME_WAIT;
printk(KERN_NOTICE "Clock: "
"deleting leap second 23:59:59 UTC\n");
printk(KERN_NOTICE
"Clock: deleting leap second 23:59:59 UTC\n");
break;
case TIME_OOP:
time_tai++;
Expand Down Expand Up @@ -199,10 +227,10 @@ void second_overflow(void)
* Compute the phase adjustment for the next second. The offset is
* reduced by a fixed factor times the time constant.
*/
tick_length = tick_length_base;
time_adj = shift_right(time_offset, SHIFT_PLL + time_constant);
time_offset -= time_adj;
tick_length += time_adj;
tick_length = tick_length_base;
time_adj = shift_right(time_offset, SHIFT_PLL + time_constant);
time_offset -= time_adj;
tick_length += time_adj;

if (unlikely(time_adjust)) {
if (time_adjust > MAX_TICKADJ) {
Expand Down Expand Up @@ -240,12 +268,13 @@ static void sync_cmos_clock(struct work_struct *work)
* 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 (!ntp_synced())
if (!ntp_synced()) {
/*
* Not synced, exit, do not restart a timer (if one is
* running, let it run out).
*/
return;
}

getnstimeofday(&now);
if (abs(now.tv_nsec - (NSEC_PER_SEC / 2)) <= tick_nsec / 2)
Expand Down Expand Up @@ -277,7 +306,8 @@ static void notify_cmos_timer(void)
static inline void notify_cmos_timer(void) { }
#endif

/* adjtimex mainly allows reading (and writing, if superuser) of
/*
* adjtimex mainly allows reading (and writing, if superuser) of
* kernel time-keeping variables. used by xntpd.
*/
int do_adjtimex(struct timex *txc)
Expand All @@ -298,7 +328,10 @@ int do_adjtimex(struct timex *txc)
if (txc->modes && !capable(CAP_SYS_TIME))
return -EPERM;

/* if the quartz is off by more than 10% something is VERY wrong! */
/*
* if the quartz is off by more than 10% then
* something is VERY wrong!
*/
if (txc->modes & ADJ_TICK &&
(txc->tick < 900000/USER_HZ ||
txc->tick > 1100000/USER_HZ))
Expand Down

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