[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.c b/drivers/s390/s390mach.c
index 442d634..806bb1a 100644
--- a/drivers/s390/s390mach.c
+++ b/drivers/s390/s390mach.c
@@ -15,7 +15,7 @@
#include <linux/time.h>
#include <linux/device.h>
#include <linux/kthread.h>
-
+#include <asm/etr.h>
#include <asm/lowcore.h>
#include <asm/cio.h>
#include "cio/cio.h"
@@ -466,6 +466,19 @@
s390_handle_damage("unable to revalidate registers.");
}
+ if (mci->cd) {
+ /* Timing facility damage */
+ s390_handle_damage("TOD clock damaged");
+ }
+
+ if (mci->ed && mci->ec) {
+ /* External damage */
+ if (S390_lowcore.external_damage_code & (1U << ED_ETR_SYNC))
+ etr_sync_check();
+ if (S390_lowcore.external_damage_code & (1U << ED_ETR_SWITCH))
+ etr_switch_to_local();
+ }
+
if (mci->se)
/* Storage error uncorrected */
s390_handle_damage("received storage error uncorrected "
@@ -504,7 +517,7 @@
machine_check_init(void)
{
init_MUTEX_LOCKED(&m_sem);
- ctl_clear_bit(14, 25); /* disable external damage MCH */
+ ctl_set_bit(14, 25); /* enable external damage MCH */
ctl_set_bit(14, 27); /* enable system recovery MCH */
#ifdef CONFIG_MACHCHK_WARNING
ctl_set_bit(14, 24); /* enable warning MCH */