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/**
* @file servo.c
* @date Tue Jul 20 16:19:19 2010
*
* @brief Code which implements the clock servo in software.
*
*
*/
#include "../ptpd.h"
void
initClock(RunTimeOpts * rtOpts, PtpClock * ptpClock)
{
DBG("initClock\n");
/* clear vars */
ptpClock->master_to_slave_delay.seconds = ptpClock->master_to_slave_delay.nanoseconds = 0;
ptpClock->slave_to_master_delay.seconds = ptpClock->slave_to_master_delay.nanoseconds = 0;
ptpClock->observed_variance = 0;
ptpClock->observed_drift = 0; /* clears clock servo accumulator (the
* I term) */
ptpClock->owd_filt.s_exp = 0; /* clears one-way delay filter */
ptpClock->halfEpoch = ptpClock->halfEpoch || rtOpts->halfEpoch;
rtOpts->halfEpoch = 0;
/* level clock */
if (!rtOpts->noAdjust)
adjFreq(0);
}
void
updateDelay(TimeInternal * send_time, TimeInternal * recv_time,
one_way_delay_filter * owd_filt, RunTimeOpts * rtOpts, PtpClock * ptpClock)
{
Integer16 s;
TimeInternal slave_to_master_delay;
DBGV("updateDelay\n");
/* calc 'slave_to_master_delay' */
subTime(&slave_to_master_delay, recv_time, send_time);
if (rtOpts->maxDelay) { /* If maxDelay is 0 then it's OFF */
if (slave_to_master_delay.seconds && rtOpts->maxDelay) {
INFO("updateDelay aborted, delay greater than 1"
" second.");
return;
}
if (slave_to_master_delay.nanoseconds > rtOpts->maxDelay) {
INFO("updateDelay aborted, delay %d greater than "
"administratively set maximum %d\n",
slave_to_master_delay.nanoseconds,
rtOpts->maxDelay);
return;
}
}
ptpClock->slave_to_master_delay = slave_to_master_delay;
/* update 'one_way_delay' */
addTime(&ptpClock->one_way_delay, &ptpClock->master_to_slave_delay, &ptpClock->slave_to_master_delay);
ptpClock->one_way_delay.seconds /= 2;
ptpClock->one_way_delay.nanoseconds /= 2;
if (ptpClock->one_way_delay.seconds) {
/* cannot filter with secs, clear filter */
owd_filt->s_exp = owd_filt->nsec_prev = 0;
return;
}
/* avoid overflowing filter */
s = rtOpts->s;
while (abs(owd_filt->y) >> (31 - s))
--s;
/* crank down filter cutoff by increasing 's_exp' */
if (owd_filt->s_exp < 1)
owd_filt->s_exp = 1;
else if (owd_filt->s_exp < 1 << s)
++owd_filt->s_exp;
else if (owd_filt->s_exp > 1 << s)
owd_filt->s_exp = 1 << s;
/* filter 'one_way_delay' */
owd_filt->y = (owd_filt->s_exp - 1) * owd_filt->y / owd_filt->s_exp +
(ptpClock->one_way_delay.nanoseconds / 2 + owd_filt->nsec_prev / 2) / owd_filt->s_exp;
owd_filt->nsec_prev = ptpClock->one_way_delay.nanoseconds;
ptpClock->one_way_delay.nanoseconds = owd_filt->y;
DBG("delay filter %d, %d\n", owd_filt->y, owd_filt->s_exp);
}
void
updateOffset(TimeInternal * send_time, TimeInternal * recv_time,
offset_from_master_filter * ofm_filt, RunTimeOpts * rtOpts, PtpClock * ptpClock)
{
TimeInternal master_to_slave_delay;
DBGV("updateOffset\n");
/* calc 'master_to_slave_delay' */
subTime(&master_to_slave_delay, recv_time, send_time);
if (rtOpts->maxDelay) { /* If maxDelay is 0 then it's OFF */
if (master_to_slave_delay.seconds && rtOpts->maxDelay) {
INFO("updateDelay aborted, delay greater than 1"
" second.");
return;
}
if (master_to_slave_delay.nanoseconds > rtOpts->maxDelay) {
INFO("updateDelay aborted, delay %d greater than "
"administratively set maximum %d\n",
master_to_slave_delay.nanoseconds,
rtOpts->maxDelay);
return;
}
}
ptpClock->master_to_slave_delay = master_to_slave_delay;
/* update 'offset_from_master' */
subTime(&ptpClock->offset_from_master, &ptpClock->master_to_slave_delay, &ptpClock->one_way_delay);
if (ptpClock->offset_from_master.seconds) {
/* cannot filter with secs, clear filter */
ofm_filt->nsec_prev = 0;
return;
}
/* filter 'offset_from_master' */
ofm_filt->y = ptpClock->offset_from_master.nanoseconds / 2 + ofm_filt->nsec_prev / 2;
ofm_filt->nsec_prev = ptpClock->offset_from_master.nanoseconds;
ptpClock->offset_from_master.nanoseconds = ofm_filt->y;
DBGV("offset filter %d\n", ofm_filt->y);
}
void
updateClock(RunTimeOpts * rtOpts, PtpClock * ptpClock)
{
Integer32 adj;
TimeInternal timeTmp;
DBGV("updateClock\n");
if (rtOpts->maxReset) { /* If maxReset is 0 then it's OFF */
if (ptpClock->offset_from_master.seconds) {
INFO("updateClock aborted, offset greater than 1"
" second.");
goto display;
}
if (ptpClock->offset_from_master.nanoseconds >
rtOpts->maxReset) {
INFO("updateClock aborted, offset %d greater than "
"administratively set maximum %d\n",
ptpClock->offset_from_master.nanoseconds,
rtOpts->maxReset);
goto display;
}
}
if (ptpClock->offset_from_master.seconds) {
/* if secs, reset clock or set freq adjustment to max */
if (!rtOpts->noAdjust) {
if (!rtOpts->noResetClock) {
getTime(&timeTmp);
subTime(&timeTmp, &timeTmp, &ptpClock->offset_from_master);
setTime(&timeTmp);
initClock(rtOpts, ptpClock);
} else {
adj = ptpClock->offset_from_master.nanoseconds > 0 ? ADJ_FREQ_MAX : -ADJ_FREQ_MAX;
adjFreq(-adj);
}
}
} else {
/* the PI controller */
/* no negative or zero attenuation */
if (rtOpts->ap < 1)
rtOpts->ap = 1;
if (rtOpts->ai < 1)
rtOpts->ai = 1;
/* the accumulator for the I component */
ptpClock->observed_drift += ptpClock->offset_from_master.nanoseconds / rtOpts->ai;
/* clamp the accumulator to ADJ_FREQ_MAX for sanity */
if (ptpClock->observed_drift > ADJ_FREQ_MAX)
ptpClock->observed_drift = ADJ_FREQ_MAX;
else if (ptpClock->observed_drift < -ADJ_FREQ_MAX)
ptpClock->observed_drift = -ADJ_FREQ_MAX;
adj = ptpClock->offset_from_master.nanoseconds / rtOpts->ap + ptpClock->observed_drift;
/* apply controller output as a clock tick rate adjustment */
if (!rtOpts->noAdjust)
adjFreq(-adj);
}
display:
if (rtOpts->displayStats)
displayStats(rtOpts, ptpClock);
DBGV("master-to-slave delay: %10ds %11dns\n",
ptpClock->master_to_slave_delay.seconds, ptpClock->master_to_slave_delay.nanoseconds);
DBGV("slave-to-master delay: %10ds %11dns\n",
ptpClock->slave_to_master_delay.seconds, ptpClock->slave_to_master_delay.nanoseconds);
DBGV("one-way delay: %10ds %11dns\n",
ptpClock->one_way_delay.seconds, ptpClock->one_way_delay.nanoseconds);
DBG("offset from master: %10ds %11dns\n",
ptpClock->offset_from_master.seconds, ptpClock->offset_from_master.nanoseconds);
DBG("observed drift: %10d\n", ptpClock->observed_drift);
}
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