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ARM: OMAP: 32k counter: Provide y2038-safe omap_read_persistent_clock() replacement

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As part of addressing "y2038 problem" for in-kernel uses, this
patch adds the y2038-safe omap_read_persistent_clock64() using
timespec64.

Because we rely on some subsequent changes to convert arm
multiarch support, omap_read_persistent_clock() will be removed
then.

Also remove the needless spinlock, because
read_persistent_clock() doesn't run simultaneously.

Signed-off-by: Xunlei Pang <pang.xunlei@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Acked-by: Tony Lindgren <tony@atomide.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1427945681-29972-5-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Xunlei Pang 2015-04-01 20:34:24 -07:00 committed by Ingo Molnar
parent 3c00a1fe84
commit a451570c00
1 changed files with 12 additions and 10 deletions
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22
arch/arm/plat-omap/counter_32k.c
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@ -44,24 +44,20 @@ static u64 notrace omap_32k_read_sched_clock(void)
}
/**
* omap_read_persistent_clock - Return time from a persistent clock.
* omap_read_persistent_clock64 - Return time from a persistent clock.
*
* Reads the time from a source which isn't disabled during PM, the
* 32k sync timer. Convert the cycles elapsed since last read into
* nsecs and adds to a monotonically increasing timespec.
* nsecs and adds to a monotonically increasing timespec64.
*/
static struct timespec persistent_ts;
static struct timespec64 persistent_ts;
static cycles_t cycles;
static unsigned int persistent_mult, persistent_shift;
static DEFINE_SPINLOCK(read_persistent_clock_lock);
static void omap_read_persistent_clock(struct timespec *ts)
static void omap_read_persistent_clock64(struct timespec64 *ts)
{
unsigned long long nsecs;
cycles_t last_cycles;
unsigned long flags;
spin_lock_irqsave(&read_persistent_clock_lock, flags);
last_cycles = cycles;
cycles = sync32k_cnt_reg ? readl_relaxed(sync32k_cnt_reg) : 0;
@ -69,11 +65,17 @@ static void omap_read_persistent_clock(struct timespec *ts)
nsecs = clocksource_cyc2ns(cycles - last_cycles,
persistent_mult, persistent_shift);
timespec_add_ns(&persistent_ts, nsecs);
timespec64_add_ns(&persistent_ts, nsecs);
*ts = persistent_ts;
}
spin_unlock_irqrestore(&read_persistent_clock_lock, flags);
static void omap_read_persistent_clock(struct timespec *ts)
{
struct timespec64 ts64;
omap_read_persistent_clock64(&ts64);
*ts = timespec64_to_timespec(ts64);
}
/**