[S390] tod clock: announce clocksource as perfect

The Time of Day clock is the standard time source for s390. It is
- monotonic
- allows very fast reading
- architecture guarantees at least microsecond stepping
- available as part of the architecture

We should announce the rate of tod as 400 to be in sync with the
description found in clocksource.h:
"400-499:Perfect The ideal clocksource. A must-use where available."

This change will prefer tod over less reliable clock sources.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/arch/s390/kernel/time.c b/arch/s390/kernel/time.c
index 48dae49bc1ec474ffe80f3eed427a610f48d48bf..a963fe81359e5bc2795ee0540b4fef600121fa20 100644 (file)
--- a/arch/s390/kernel/time.c
+++ b/arch/s390/kernel/time.c
@@ -307,7 +307,7 @@ static cycle_t read_tod_clock(void)
 
 static struct clocksource clocksource_tod = {
        .name           = "tod",
-       .rating         = 100,
+       .rating         = 400,
        .read           = read_tod_clock,
        .mask           = -1ULL,
        .mult           = 1000,