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[S390] add read_persistent_clock

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Add a read_persistent_clock function that does not just return 0.
Since timekeeping_init calls the function before time_init has been
called move reset_tod_clock to early.c to make sure that the TOD
clock is running when read_persistent_clock is invoked.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Martin Schwidefsky
2009-04-14 15:36:28 +02:00
parent 5b409ed17b
commit b6112ccbff
4 changed files with 35 additions and 21 deletions
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28
arch/s390/kernel/time.c
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@@ -52,9 +52,6 @@
#define USECS_PER_JIFFY ((unsigned long) 1000000/HZ)
#define CLK_TICKS_PER_JIFFY ((unsigned long) USECS_PER_JIFFY << 12)
/* The value of the TOD clock for 1.1.1970. */
#define TOD_UNIX_EPOCH 0x7d91048bca000000ULL
/*
* Create a small time difference between the timer interrupts
* on the different cpus to avoid lock contention.
@@ -63,9 +60,10 @@
#define TICK_SIZE tick
u64 sched_clock_base_cc = -1; /* Force to data section. */
static ext_int_info_t ext_int_info_cc;
static ext_int_info_t ext_int_etr_cc;
static u64 sched_clock_base_cc;
static DEFINE_PER_CPU(struct clock_event_device, comparators);
@@ -195,22 +193,12 @@ static void timing_alert_interrupt(__u16 code)
static void etr_reset(void);
static void stp_reset(void);
/*
* Get the TOD clock running.
*/
static u64 __init reset_tod_clock(void)
unsigned long read_persistent_clock(void)
{
u64 time;
struct timespec ts;
etr_reset();
stp_reset();
if (store_clock(&time) == 0)
return time;
/* TOD clock not running. Set the clock to Unix Epoch. */
if (set_clock(TOD_UNIX_EPOCH) != 0 || store_clock(&time) != 0)
panic("TOD clock not operational.");
return TOD_UNIX_EPOCH;
tod_to_timeval(get_clock() - TOD_UNIX_EPOCH, &ts);
return ts.tv_sec;
}
static cycle_t read_tod_clock(void)
@@ -265,7 +253,9 @@ void update_vsyscall_tz(void)
*/
void __init time_init(void)
{
sched_clock_base_cc = reset_tod_clock();
/* Reset time synchronization interfaces. */
etr_reset();
stp_reset();
/* set xtime */
tod_to_timeval(sched_clock_base_cc - TOD_UNIX_EPOCH, &xtime);