[time-nuts] Soekris NET4501, NTP, PPS and "Inappropriate ioctl"

[Mike S]

I'm putting together an NTP server on a Soekris NET4501, using an 
Oncore M12+. I can't get the Atom PPS refclock to load, it reports 
"refclock_atom: time_pps_create failed: Inappropriate ioctl for 
device." (/dev/pps0 is linked to /dev/elan-mmcr)

I can get it working using only the Oncore refclock driver if I also 
provide the PPS signal to /dev/cuau1 DCD pin (/dev/oncore.pps.0 linked 
to /dev/cuau1), but I'm pretty sure that doesn't then use the special 
timer available on the 4501, just the "plain old" Oncore PPS. (linking 
/dev/oncore.pps.0 to /dev/elan-mmcr doesn't work, either)

I'm asking the group for help, since many have been down a similar path 
with NTP on the NET4501. I'm past the "dangerous" stage in *nix 
userspace, have previously patched PPS into a Debian kernel and gotten 
it working, but get lost with low level stuff.

These are the relevant config settings. I've tried both with/without 
PPS_SYNC. FreeBSD 8.1-RELEASE:
---
Kernel config:
cpu             I486_CPU
ident           SOEKRIS

options         CPU_ELAN
options         CPU_SOEKRIS
options         HZ=1000
options         CPU_ELAN_PPS
options         GEOM_VOL
options         PPS_SYNC
...
---
nanobsd config: I don't think anything special is required here. ntpd 
version 4.2.4p5 is installed by default.
---
/dev :
lrwxr-xr-x  1 root  wheel            5 Oct 31 13:18 oncore.pps.0 -> 
cuau1
lrwxr-xr-x  1 root  wheel            5 Oct 31 13:18 oncore.serial.0 -> 
cuau1
lrwxr-xr-x  1 root  wheel            9 Oct 31 13:18 pps0 -> elan-mmcr
---
ntp.conf:
#
tos mindist 0.050
# Motorola Oncore M12+ Timing
server 127.127.30.0 ttl 1 prefer minpoll 4 maxpoll 4
# PPS
server 127.127.22.0 minpoll 4 maxpoll 4