Commit Graph

2 Commits

Author SHA1 Message Date
David S. Miller 3586e0a9a4 clocksource/timecompare: Fix symbol exports to be GPL'd.
Noticed by Thomas GLeixner.

Signed-off-by: David S. Miller <davem@davemloft.net>
2009-11-11 19:06:30 -08:00
Patrick Ohly a75244c3d5 timecompare: generic infrastructure to map between two time bases
Mapping from a struct timecounter to a time returned by functions like
ktime_get_real() is implemented. This is sufficient to use this code
in a network device driver which wants to support hardware time
stamping and transformation of hardware time stamps to system time.

The interface could have been made more versatile by not depending on
a time counter, but this wasn't done to avoid writing glue code
elsewhere.

The method implemented here is the one used and analyzed under the name
"assisted PTP" in the LCI PTP paper:
http://www.linuxclustersinstitute.org/conferences/archive/2008/PDF/Ohly_92221.pdf

Acked-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Patrick Ohly <patrick.ohly@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-02-15 22:43:32 -08:00