Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

The 1588 standard talks extensively about "mean path delay"
and the meanPathDelay variable.   Even if the name is not the
best one, we'd better rename the fields and variable.

This is a massive change, but the currenct code has been validated at
the Lemgo plug fest, and I don't expect any need to revert older
patches at this point.  I'm sorry for git-blame users, including myself,
but this change is a step forward.  I should have knonw better when
choosing "one way delay" between the two names of the older code.

Thanks to Aurelio for noting the problem.
Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

We want to turn PPS output on or off when it changes, not each and every
time. This is both to avoid wasting CPU cycles and to allow developers
to activate pps even when not synced or badly-synced.
Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

This is the true and solid UDP support for WR. It manages both
WR and non-WR communication, both as master and slave.

The previous commit was wrong:

  5c918341 wrs-socket: if UDP is requested, fall back to non-WR

the reason is that we can't use Unix timestamps and WR time: to discipline
the WR mechanism we need to collect WR timestamps. So now UDP is part
of wrs-socket.c, to use the WR timestamps from hardware.
Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

This split out of an helper to enable timestamping is needed to
support the UDP protocol, in a later commit.  No, it is not needed,
but it's useful anyways.
Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

Commit

	06cb0670 time-wrs: implement time_set()

is changin the seconds leaving the fractional part alone. However, the
servo won't time-set again, but will rather converge, and this takes time.

We now adjust nanoseconds first, so the servo will still notice a
more-than-one-second error and will call our time-set again. Thus,
we jump to proper time in a few seconds instead of slowly converging from
far away.
Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

We definitely need to take care of currentUtcOffset, but the current
implementation was wrong: it only used it in modifying receive stamps,
thus achieving completely wrong tuples.

It's the receive function that must apply the utcOffset, or not,
according to how it timestamps frames.  Similarly, it's the time
setting functions that must use utcOffset, or not, according to whether
the time is utc (e.g.: unix) or tai (e.g.: wr).

So this just removes a wrong attempt, waiting for good stuff to be written.
Anyways, the utcOffset reported by the master is kept in data structures
and passed over to slaves.
Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

The servo is now using this bit, so it should be set by all stampers.
Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

The non-wr servo calls time_set when the offset is more than 1second.
However, we can't set the time, but we can force a big adjustment.

So this code now adjusts the WR seconds, to reach a less-than-one-second
error, to let the servo rthen converge with small adjustments.
Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

When offset from master is more than one second, the code used to
time->get, subtract and then time->set.

However, in white rabbit we cannot get the WR time and time->get
returns the unix time instead. The only way to have hardware time is
timestamping a frame.  Thus, use the master's "T4" that we just
received plus the one-way-delay as an approximation of the current
hardware time. Later T1..T4 tuples will complete the fine
synchronization.
Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

Suggested by Aurelio and Maciej
Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

set to -1 all unused sockets, so FS_SET won't crash if, for example,
we request UDP on a port with no IPV4 address, after the message:

   unix_open_ch: ioctl(SIOCGIFADDR): Cannot assign requested address

While at it, I factorized some common code.
Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

This commit factorizes some code in lib/conf.c from the two hosted
startup files, but the aim is passing "-f <filename>" on the command
line, to test with unconventional setups without touching the "real"
filesystem.

Now ppsi looks for the configuration file is from threee places, in
this order:
    - command line, if any
    - architecture-specific, if any (e.g. "/wr/etc/ppsi.conf")
    - compile-time default ("/etc/ppsi.conf")
Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

The next commit makes a little order in startup files, and config file
parsing ends up after all allocations, so we can't reply on
ppg->nlinks to be properly set.

In hosted environments we have no issues with a few kilobytes more, so
allocate the max number of instances even if less are used.
Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

If we run both Ethernet and UDP services in a 18-port switch, we need
36 logical links. Thus, increase the previous limit of 32 to 64,
knowing we have no serious memory constraints in hosted environments.

The definition is moved to <ppsi/constants.h> as implementation-specific.
Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

When running a WR device as non-WR slave, we adjust the clock instead
of the phase.  When adjusting the counters, timestamps are reported as
invalid until two increments of the "seconds" register.

So, when T3 is not valid (tx stamp of delay_request), avoid running
the non-WR servo. A later iteration of the slave FSM will work.
Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

When setting time, set Unix time as well. And when asking for the time,
return Unix time if the WR inter process communication fails.

Currently (and in all past history) the IPC call to get the time is
not implemented, so we are sure we fail. But I keep it in place nonetheless
in case we'll have it working in the future. Such time_get calls are
mainly for timestamping the diagnostic messages anyways.
Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

This function allows a servo to initialize its hardware and return the
current "observed drift" value that is in charge.

In unix-time this is used to return the current value for frequency
correction -- being consistent with current naming and use of values,
which unfortunately is not really correct.
Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

In my opinion, it makes no sense to make calculations with a
well-filtered OWD and the instantaneous OFM, which is subject to the
same oscillations.  Thus, this commit filters OFM with the same rules
used for OWD.

However, the detection of outliers is more difficult because OFM can
have either sign, and OFM is really changing while we are not yet
synchronized.  So the code does the following:

- if we are at PP_ADJ_FREQ_MAX it means we are bridging a gap as
fast as possible. In that case, don't average OFM.

- if we receive a bigger-than-expected OFM value, trim it, but relax
the expectation so we can track a real change if futher samples confirm
it or push it farther.

- if the averaged OFM changed sign, start averaging from scratch.

The second item works by keeping the average of ofm magnitude, and we
accept a change no bigger than the averaged magnitude.  So, if we are
synced in the millisecond range we accept changes of the order of
milliseconds (this usually applies while syncing, and OFM is expected
to change in that case); if we are in the microsecond range outliers
move us by a few microseconds, but such trimming is then relaxed so we
increase our ability to move exponentially.

The last item prevents oscillations: this OFM is fed to a PI controller,
so if we are late in responding to changes in sign, both P and I
continue pushing in the wrong direction. So, combining the average and
the PI we have an almost inversion in phase of the error, and the
servo oscillates a lot while converging.

Unfortunately, while working on this I realized there's a bug when
dealing with very short and consistent timestamps. For example, a
current average of 20ns, will never reach 40ns even if all further
samples request 40ns, due to integer truncation.  We need to either
move to floating point or count fractional bits as the magnitudes
permit.
Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

This commit almost ignores long owd values. They happen when there are
software delays; for example I sometimes see 7ms RTT values every now
and then, which destroy synchronization by a few hundred microseconds.

I "almost" ignore them, by using an OWD value twice as the current
average.  This is meant to gradually recover if the real OWD is bigger
than what we initially measured (e.g., initially the slave clock was
too slow during a recovery).

The commit also slightly reorders some calculation to be safer in
dealing with errors in initial values.
Signed-off-by: Alessandro Rubini <rubini@gnudd.com>

This commit makes the servo engine discard events where "one way
delay" is over one second (this will be documented).  The management
was never tested and likely wrong anyways.

It also ignores events where the trip time appears to be negative.  In
this case the calculation is brought forward with the current value
for one way delay (the current average).  This happens when the slave
is running a faster clock than the master during recovery.
Signed-off-by: Alessandro Rubini <rubini@gnudd.com>