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fetch RTC count more atomically

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This commit is contained in:
Dan Halbert 2022-02-09 15:32:16 -05:00
parent da035fe958
commit b18b0fd5b9
1 changed files with 23 additions and 13 deletions
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36
ports/atmel-samd/supervisor/port.c
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@ -498,21 +498,31 @@ uint32_t port_get_saved_word(void) {
static volatile uint64_t overflowed_ticks = 0;
static uint32_t _get_count(uint64_t *overflow_count) {
#ifdef SAM_D5X_E5X
while ((RTC->MODE0.SYNCBUSY.reg & (RTC_MODE0_SYNCBUSY_COUNTSYNC | RTC_MODE0_SYNCBUSY_COUNT)) != 0) {
}
#endif
// SAMD21 does continuous sync so we don't need to wait here.
while(1) {
// Disable interrupts so we can grab the count and the overflow atomically.
common_hal_mcu_disable_interrupts();
// Disable interrupts so we can grab the count and the overflow.
common_hal_mcu_disable_interrupts();
uint32_t count = RTC->MODE0.COUNT.reg;
if (overflow_count != NULL) {
*overflow_count = overflowed_ticks;
}
common_hal_mcu_enable_interrupts();
#ifdef SAM_D5X_E5X
while ((RTC->MODE0.SYNCBUSY.reg & (RTC_MODE0_SYNCBUSY_COUNTSYNC | RTC_MODE0_SYNCBUSY_COUNT)) != 0) {
}
#endif
// SAMD21 does continuous sync so we don't need to wait here.
return count;
uint32_t count = RTC->MODE0.COUNT.reg;
if (overflow_count != NULL) {
*overflow_count = overflowed_ticks;
}
bool overflow_pending = RTC->MODE0.INTFLAG.bit.OVF;
common_hal_mcu_enable_interrupts();
if (!overflow_pending) {
return count;
}
// Try again if overflow hasn't been processed yet.
}
}
volatile bool _woken_up;