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Subject[PATCH 05/21] ARM: tegra: clock: Provide y2038-safe tegra_read_persistent_clock() replacement
Date
From: Xunlei Pang <pang.xunlei@linaro.org>

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.

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Xunlei Pang <pang.xunlei@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
drivers/clocksource/tegra20_timer.c | 21 ++++++++++++++-------
1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/drivers/clocksource/tegra20_timer.c b/drivers/clocksource/tegra20_timer.c
index d8a3a4e..4a0a603 100644
--- a/drivers/clocksource/tegra20_timer.c
+++ b/drivers/clocksource/tegra20_timer.c
@@ -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)
--
1.9.1


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