Messages in this thread | | | Subject | Re: [PATCH 5/8] support for TAI | From | john stultz <> | Date | Fri, 14 Mar 2008 13:55:05 -0700 |
| |
On Fri, 2008-03-14 at 19:40 +0100, zippel@linux-m68k.org wrote: > plain text document attachment (time_tai) > This adds support for setting the TAI value (International Atomic Time). > The value is reported back to userspace via timex (as we don't have a > ntp_gettime() syscall). > > Signed-off-by: Roman Zippel <zippel@linux-m68k.org> >
Very cool. I just was talking with someone who was looking for a TAI interface.
Minor nit below.
-john
> Index: linux-2.6-mm/kernel/time/ntp.c > =================================================================== > --- linux-2.6-mm.orig/kernel/time/ntp.c > +++ linux-2.6-mm/kernel/time/ntp.c > @@ -35,6 +35,7 @@ static u64 tick_length, tick_length_base > /* 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) */
I think timekeeping.c would be the better place for time_tai, keeping it closer to xtime and wall_to_monotonic's definitions.
> static s64 time_offset; /* time adjustment (ns) */ > static long time_constant = 2; /* pll time constant */ > long time_maxerror = NTP_PHASE_LIMIT; /* maximum error (us) */ > @@ -162,6 +163,7 @@ void second_overflow(void) > case TIME_DEL: > if ((xtime.tv_sec + 1) % 86400 == 0) { > xtime.tv_sec++; > + time_tai--; > wall_to_monotonic.tv_sec--; > time_state = TIME_WAIT; > printk(KERN_NOTICE "Clock: deleting leap second " > @@ -169,6 +171,7 @@ void second_overflow(void) > } > break; > case TIME_OOP: > + time_tai++; > time_state = TIME_WAIT; > break; > case TIME_WAIT:
These manipulations could also be done in the timekeeping_insert/remove_second interface I suggested earlier.
> @@ -340,6 +343,9 @@ int do_adjtimex(struct timex *txc) > time_constant = max(time_constant, 0l); > } > > + if (txc->modes & ADJ_TAI && txc->constant > 0) > + time_tai = txc->constant; > + > if (txc->modes & ADJ_OFFSET) { > if (txc->modes == ADJ_OFFSET_SINGLESHOT) > /* adjtime() is independent from ntp_adjtime() */ > @@ -375,6 +381,7 @@ int do_adjtimex(struct timex *txc) > txc->precision = 1; > txc->tolerance = MAXFREQ_SCALED / PPM_SCALE; > txc->tick = tick_usec; > + txc->tai = time_tai; > > /* PPS is not implemented, so these are zero */ > txc->ppsfreq = 0; >
| |