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Commit a451570c authored by Xunlei Pang's avatar Xunlei Pang Committed by Ingo Molnar
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ARM: OMAP: 32k counter: Provide y2038-safe omap_read_persistent_clock() replacement 



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: default avatarXunlei Pang <pang.xunlei@linaro.org>
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
Acked-by: default avatarTony 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: default avatarIngo Molnar <mingo@kernel.org>
parent 3c00a1fe

arch/arm/plat-omap/counter_32k.c

+12 −10
Original line number Diff line number Diff line
@@ -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;

}



static void omap_read_persistent_clock(struct timespec *ts)

{

	struct timespec64 ts64;



	spin_unlock_irqrestore(&read_persistent_clock_lock, flags);

	omap_read_persistent_clock64(&ts64);

	*ts = timespec64_to_timespec(ts64);

}



/**