tree dee5b6a3589cfaae698a11297667e9e0c8b01ef5
parent a038a353c3de4040d8445ec568acebdac144436f
author Patrick Ohly <patrick.ohly@intel.com> 1234415015 +0000
committer David S. Miller <davem@davemloft.net> 1234766612 -0800

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>