aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/s390/s390mach.h
diff options
context:
space:
mode:
authorMartin Schwidefsky <schwidefsky@de.ibm.com>2007-02-05 15:18:19 -0500
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2007-02-05 15:18:19 -0500
commitd54853ef8cb17296ac7bce9c77430fb7c80532d0 (patch)
tree649e14d532e17231225a042a7c9a3d9207ad91ee /drivers/s390/s390mach.h
parentc1821c2e9711adc3cd298a16b7237c92a2cee78d (diff)
[S390] ETR support.
This patch adds support for clock synchronization to an external time reference (ETR). The external time reference sends an oscillator signal and a synchronization signal every 2^20 microseconds to keep the TOD clocks of all connected servers in sync. For availability two ETR units can be connected to a machine. If the clock deviates for more than the sync-check tolerance all cpus get a machine check that indicates that the clock is out of sync. For the lovely details how to get the clock back in sync see the code below. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'drivers/s390/s390mach.h')
-rw-r--r--drivers/s390/s390mach.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/s390/s390mach.h b/drivers/s390/s390mach.h
index 7abb42a09ae2..d3ca4281a494 100644
--- a/drivers/s390/s390mach.h
+++ b/drivers/s390/s390mach.h
@@ -102,4 +102,7 @@ static inline int stcrw(struct crw *pcrw )
102 return ccode; 102 return ccode;
103} 103}
104 104
105#define ED_ETR_SYNC 12 /* External damage ETR sync check */
106#define ED_ETR_SWITCH 13 /* External damage ETR switch to local */
107
105#endif /* __s390mach */ 108#endif /* __s390mach */