[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>
diff --git a/drivers/s390/s390mach.h b/drivers/s390/s390mach.h
index 7abb42a..d3ca428 100644
--- a/drivers/s390/s390mach.h
+++ b/drivers/s390/s390mach.h
@@ -102,4 +102,7 @@
return ccode;
}
+#define ED_ETR_SYNC 12 /* External damage ETR sync check */
+#define ED_ETR_SWITCH 13 /* External damage ETR switch to local */
+
#endif /* __s390mach */