[RTEMS Project] #2348: Timecounter: Add NTP support

[RTEMS trac]

#2348: Timecounter: Add NTP support
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 Reporter:  Sebastian Huber  |       Owner:  (none)
     Type:  enhancement      |      Status:  new
 Priority:  normal           |   Milestone:  Indefinite
Component:  score            |     Version:
 Severity:  normal           |  Resolution:
 Keywords:                   |  Blocked By:
 Blocking:                   |
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Comment (by Sebastian Huber):

 Good timing, I recently updated kern_tc.c to the latest FreeBSD version:

 https://git.rtems.org/sebh/rtems.git/log/?h=timecounter-2021

 I just didn't send the patch set for review yet, since nobody commented on
 the new clock manager directives so far:

 https://lists.rtems.org/pipermail/devel/2021-October/069697.html

 The kern_tc.c is quite close to the original FreeBSD code and the Doxygen
 comment block on top of the file is not an issue.

 In this patch set I removed the NTP code block since nobody was interested
 in NTP support in the last 6 years:

 https://git.rtems.org/sebh/rtems.git/commit/?h=timecounter-2021&id=f85259b1edfff1d89c013c97510a9427825ea81b

 This enabled a performance optimization here:

 https://git.rtems.org/sebh/rtems.git/commit/?h=timecounter-2021&id=04ed8d3c8cf88b7f1e3fb7ad78a91be1fefc396c

 The performance optimization is important for targets with slow 64-bit
 divisions (which are most RTEMS targets). If you want to add NTP support,
 then we have to restructure the FreeBSD code a bit. This can be integrated
 in FreeBSD. I can do this it just depends on how urgent it is.

 In a first approach the proposed callback makes sense. If someone using
 lwIP needs NTP support, then we can add kern_ntptime.c to RTEMS.

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Ticket URL: <http://devel.rtems.org/ticket/2348#comment:3>
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