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s390/time: cleanup etr leftovers 

There are still some etr leftovers and wrong comments, let's clean that up.

Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
David Hildenbrand 2016-07-14 13:38:06 +02:00 committed by Martin Schwidefsky
parent 41ad022039
commit ca64f63901
1 changed files with 9 additions and 21 deletions
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30
arch/s390/kernel/time.c
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@ -318,10 +318,8 @@ static DEFINE_PER_CPU(atomic_t, clock_sync_word);
static DEFINE_MUTEX(clock_sync_mutex); static DEFINE_MUTEX(clock_sync_mutex);
static unsigned long clock_sync_flags; static unsigned long clock_sync_flags;
#define CLOCK_SYNC_HAS_ETR 0 #define CLOCK_SYNC_HAS_STP 0
#define CLOCK_SYNC_HAS_STP 1 #define CLOCK_SYNC_STP 1
#define CLOCK_SYNC_ETR 2
#define CLOCK_SYNC_STP 3
/* /*
* The get_clock function for the physical clock. It will get the current * The get_clock function for the physical clock. It will get the current
@ -343,34 +341,32 @@ int get_phys_clock(unsigned long long *clock)
if (sw0 == sw1 && (sw0 & 0x80000000U)) if (sw0 == sw1 && (sw0 & 0x80000000U))
/* Success: time is in sync. */ /* Success: time is in sync. */
return 0; return 0;
if (!test_bit(CLOCK_SYNC_HAS_ETR, &clock_sync_flags) && if (!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
!test_bit(CLOCK_SYNC_HAS_STP, &clock_sync_flags))
return -EOPNOTSUPP; return -EOPNOTSUPP;
if (!test_bit(CLOCK_SYNC_ETR, &clock_sync_flags) && if (!test_bit(CLOCK_SYNC_STP, &clock_sync_flags))
!test_bit(CLOCK_SYNC_STP, &clock_sync_flags))
return -EACCES; return -EACCES;
return -EAGAIN; return -EAGAIN;
} }
EXPORT_SYMBOL(get_phys_clock); EXPORT_SYMBOL(get_phys_clock);
/* /*
* Make get_sync_clock return -EAGAIN. * Make get_phys_clock() return -EAGAIN.
*/ */
static void disable_sync_clock(void *dummy) static void disable_sync_clock(void *dummy)
{ {
atomic_t *sw_ptr = this_cpu_ptr(&clock_sync_word); atomic_t *sw_ptr = this_cpu_ptr(&clock_sync_word);
/* /*
* Clear the in-sync bit 2^31. All get_sync_clock calls will * Clear the in-sync bit 2^31. All get_phys_clock calls will
* fail until the sync bit is turned back on. In addition * fail until the sync bit is turned back on. In addition
* increase the "sequence" counter to avoid the race of an * increase the "sequence" counter to avoid the race of an
* etr event and the complete recovery against get_sync_clock. * stp event and the complete recovery against get_phys_clock.
*/ */
atomic_andnot(0x80000000, sw_ptr); atomic_andnot(0x80000000, sw_ptr);
atomic_inc(sw_ptr); atomic_inc(sw_ptr);
} }
/* /*
* Make get_sync_clock return 0 again. * Make get_phys_clock() return 0 again.
* Needs to be called from a context disabled for preemption. * Needs to be called from a context disabled for preemption.
*/ */
static void enable_sync_clock(void) static void enable_sync_clock(void)
@ -393,7 +389,7 @@ static inline int check_sync_clock(void)
return rc; return rc;
} }
/* Single threaded workqueue used for etr and stp sync events */ /* Single threaded workqueue used for stp sync events */
static struct workqueue_struct *time_sync_wq; static struct workqueue_struct *time_sync_wq;
static void __init time_init_wq(void) static void __init time_init_wq(void)
@ -407,20 +403,12 @@ struct clock_sync_data {
atomic_t cpus; atomic_t cpus;
int in_sync; int in_sync;
unsigned long long fixup_cc; unsigned long long fixup_cc;
int etr_port;
struct etr_aib *etr_aib;
}; };
static void clock_sync_cpu(struct clock_sync_data *sync) static void clock_sync_cpu(struct clock_sync_data *sync)
{ {
atomic_dec(&sync->cpus); atomic_dec(&sync->cpus);
enable_sync_clock(); enable_sync_clock();
/*
* This looks like a busy wait loop but it isn't. etr_sync_cpus
* is called on all other cpus while the TOD clocks is stopped.
* __udelay will stop the cpu on an enabled wait psw until the
* TOD is running again.
*/
while (sync->in_sync == 0) { while (sync->in_sync == 0) {
__udelay(1); __udelay(1);
/* /*