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clocksource/drivers/tegra: Provide y2038-safe tegra_read_persistent_clock() replacement 

As part of addressing "y2038 problem" for in-kernel uses, this
patch adds the y2038-safe tegra_read_persistent_clock64() using
timespec64.

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

Signed-off-by: Xunlei Pang <pang.xunlei@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Acked-by: Thierry Reding <treding@nvidia.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1427945681-29972-6-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 20:34:25 -07:00 committed by Ingo Molnar
parent a451570c00
commit a0c2998f91
1 changed files with 14 additions and 7 deletions
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21
drivers/clocksource/tegra20_timer.c
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@ -51,7 +51,7 @@
static void __iomem *timer_reg_base;
static void __iomem *rtc_base;
static struct timespec persistent_ts;
static struct timespec64 persistent_ts;
static u64 persistent_ms, last_persistent_ms;
static struct delay_timer tegra_delay_timer;
@ -120,26 +120,33 @@ static u64 tegra_rtc_read_ms(void)
}
/*
* tegra_read_persistent_clock - Return time from a persistent clock.
* tegra_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.
* Care must be taken that this funciton is not called while the
* tegra_rtc driver could be executing to avoid race conditions
* on the RTC shadow register
*/
static void tegra_read_persistent_clock(struct timespec *ts)
static void tegra_read_persistent_clock64(struct timespec64 *ts)
{
u64 delta;
struct timespec *tsp = &persistent_ts;
last_persistent_ms = persistent_ms;
persistent_ms = tegra_rtc_read_ms();
delta = persistent_ms - last_persistent_ms;
timespec_add_ns(tsp, delta * NSEC_PER_MSEC);
*ts = *tsp;
timespec64_add_ns(&persistent_ts, delta * NSEC_PER_MSEC);
*ts = persistent_ts;
}
static void tegra_read_persistent_clock(struct timespec *ts)
{
struct timespec ts64;
tegra_read_persistent_clock64(&ts64);
*ts = timespec64_to_timespec(ts64);
}
static unsigned long tegra_delay_timer_read_counter_long(void)