johnhay / timecard

Freebsd driver for the TimeCard

Summary

This is a FreeBSD driver for the Open Compute Project (OCP) Time Appliance Project (TAP) Time Card

The software consists of two main parts:

• The kernel module timecard(4):

  • Provides access to the card’s functionality,
  • Implements a timecounter, “TimeCard”, using the timecounters(4) API,
  • Make the PPS signal and timestamp available with the RFC 2783 Pulse Per Second (PPS) API,
  • Provides a timecard bus to which uart(4), iicbus(4) and spibus(4) drivers can attach.

• A daemon timecard(8):

  • Provides a shm(28) driver for ntpd(8),
  • Synchronize the kernel time to the timecard(4) time,
  • Discipline or train the clock on board of the TimeCard through the iic(4) Clock interface.

Building from source:

To build requires a FreeBSD 14.0 or later, environment with the FreeBSD source in /usr/src. Extract (git pull, clone, tar…) this source and change into that directory.

make # to compile everything as any user
make package # to build a FreeBSD package of it all

The package includes rc.d startup files that can be steered from /etc/rc.conf. For example:

timecard_enable="YES"
timecard_logfile="/var/log/tc/tc.log"
timecard_driftfile="/var/log/tc/driftfile.txt"
timecard_flags="-c -h -s -t -v"

To configure ntpd(8) to use the timecard through the shm interface, add the following lines to /etc/ntp.conf:

server 127.127.28.0 minpoll 4 maxpoll 4 prefer
fudge 127.127.28.0 refid TC flag4 1