[Soekris] FreeBSD tweaks for soekris board...
phk at freebsd.org
Wed Sep 4 20:20:15 UTC 2002
I have changed the ElanSC520 support from being a device driver
(device elan-mmcr) to an option (options CPU_ELAN) for technical
I have also introduced code to use GP-timer#2 as timecounter, but
this only works of you have HZ=150 or higher.
This timecounter runs at 8.3 MHz instead of the 1.18 MHz of the
i8254 timecounter so timestamps have better resolution, but what
is more important, it takes roughly 10 microseconds less to produce
a timestamp and it doesn't disable/enable interrupts doing so.
This timecounter derives it frequency from the 33.333 MHz X-tal
instead of the 32768Hz X-tal on the motherboard, so you will see
ntpd settle on a different frequency offset after this change.
These changes have only been made in -current so far, I have no
-stable soekris cards to test on, so I will refrain from MFC'ing.
Others are welcome to do so and Sam has already threathend to do it.
The watch-dog is one of my next targets, and I plan to make work
the following way:
The kernel configures and tickles the watchdog.
If a user-process opens "/dev/elan-mmcr" and issues the
correct ioctl to tickle the watch-dog, the kernel stops
doing it, and leaves user-land in charge.
Once "/dev/elan-mmcr" is closed for the last time, the
kernel resumes the tickling, unless an ioctl has told
it specifically not to.
Finally, and ioctl can tell the kernel to immediately
reboot if "/dev/elan-mmcr" is closed.
Would that work for you guys ?
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
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