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: Xunlei Pang <[email protected]>
Signed-off-by: John Stultz <[email protected]>
Acked-by: Tony Lindgren <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

diff --git a/arch/arm/plat-omap/counter_32k.c b/arch/arm/plat-omap/counter_32k.c
index 43cf74561cfd02fa6b350f8a3b41410b9407f8a6..b7b7b0793228d9e343258ab31c01c52d40a62d24 100644 (file)
--- a/arch/arm/plat-omap/counter_32k.c
+++ b/arch/arm/plat-omap/counter_32k.c
@@ -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);
 }
 
 /**