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drivers: timer: adsp: Improve elapsed ticks calculations

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It is better to use 64-bit variable types for calculating the number
of elapsed ticks than 32-bit variable types. This guards against the
propagation of calculation errors should the lower 32-bits of the timer
counter roll over multiple times before the timer ISR is serviced.

(Such a scenario can easily occur when pausing the system for an
extended period of time with a debugging device such as a Lauterbach.)

Signed-off-by: Peter Mitsis <peter.mitsis@intel.com>
This commit is contained in:
Peter Mitsis 2022-10-05 10:02:33 -04:00 committed by Anas Nashif
parent ff46de7838
commit d308ca5695
1 changed files with 5 additions and 5 deletions
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10
drivers/timer/intel_adsp_timer.c
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@ -96,12 +96,12 @@ static void compare_isr(const void *arg)
{
ARG_UNUSED(arg);
uint64_t curr;
uint32_t dticks;
uint64_t dticks;
k_spinlock_key_t key = k_spin_lock(&lock);
curr = count();
dticks = (uint32_t)((curr - last_count) / CYC_PER_TICK);
dticks = (curr - last_count) / CYC_PER_TICK;
/* Clear the triggered bit */
*WCTCS |= DSP_WCT_CS_TT(COMPARATOR_IDX);
@ -119,7 +119,7 @@ static void compare_isr(const void *arg)
k_spin_unlock(&lock, key);
sys_clock_announce(dticks);
sys_clock_announce((int32_t)dticks);
}
void sys_clock_set_timeout(int32_t ticks, bool idle)
@ -160,10 +160,10 @@ uint32_t sys_clock_elapsed(void)
return 0;
}
k_spinlock_key_t key = k_spin_lock(&lock);
uint32_t ret = (count32() - (uint32_t)last_count) / CYC_PER_TICK;
uint64_t ret = (count() - last_count) / CYC_PER_TICK;
k_spin_unlock(&lock, key);
return ret;
return (uint32_t)ret;
}
uint32_t sys_clock_cycle_get_32(void)