[PATCH] clocksource/drivers/pistachio: Fix wrong calculated clocksource read value

From: Jisheng Zhang
Date: Wed Nov 25 2015 - 10:47:05 EST


Let's assume the counter value is 0xf000000, the pistachio clocksource
read cycles function would return 0xffffffff0fffffff, but it should
return 0xfffffff.

We fix this issue by calculating bitwise-not counter, then cast to
cycle_t.

Signed-off-by: Jisheng Zhang <jszhang@xxxxxxxxxxx>
---
drivers/clocksource/time-pistachio.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/clocksource/time-pistachio.c b/drivers/clocksource/time-pistachio.c
index bba6799..3269d9e 100644
--- a/drivers/clocksource/time-pistachio.c
+++ b/drivers/clocksource/time-pistachio.c
@@ -84,7 +84,7 @@ pistachio_clocksource_read_cycles(struct clocksource *cs)
counter = gpt_readl(pcs->base, TIMER_CURRENT_VALUE, 0);
raw_spin_unlock_irqrestore(&pcs->lock, flags);

- return ~(cycle_t)counter;
+ return (cycle_t)~counter;
}

static u64 notrace pistachio_read_sched_clock(void)
--
2.6.2

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