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drivers: timer: stm32_lptim: fix sys_clock_* return value

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This commit finish to fix the bug describe by 85e2a0679a68f02f7ef.
With the previous correction, the uptime read could be in the past:
if the counter rewinds just after testing ARRM flag, we had lost
some counts.

Signed-off-by: Julien D'Ascenzio <julien.dascenzio@paratronic.fr>
This commit is contained in:
Julien D'Ascenzio 2023-01-13 12:07:43 +01:00 • committed by Fabio Baltieri
commit 704ca8f1b4
1 changed files with 31 additions and 26 deletions
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57
drivers/timer/stm32_lptim_timer.c
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@ -86,6 +86,11 @@ static struct k_spinlock lock;
#endif
#endif /* !CONFIG_STM32_LPTIM_TICK_FREQ_RATIO_OVERRIDE */
static inline bool arrm_state_get(void)
{
return (LL_LPTIM_IsActiveFlag_ARRM(LPTIM) && LL_LPTIM_IsEnabledIT_ARRM(LPTIM));
}
static void lptim_irq_handler(const struct device *unused)
{
@ -105,9 +110,7 @@ static void lptim_irq_handler(const struct device *unused)
}
}
if ((LL_LPTIM_IsActiveFlag_ARRM(LPTIM) != 0)
&& LL_LPTIM_IsEnabledIT_ARRM(LPTIM) != 0) {
if (arrm_state_get()) {
k_spinlock_key_t key = k_spin_lock(&lock);
/* do not change ARR yet, sys_clock_announce will do */
@ -238,6 +241,29 @@ void sys_clock_set_timeout(int32_t ticks, bool idle)
k_spin_unlock(&lock, key);
}
static uint32_t sys_clock_lp_time_get(void)
{
uint32_t lp_time;
do {
/* In case of counter roll-over, add the autoreload value,
* because the irq has not yet been handled
*/
if (arrm_state_get()) {
lp_time = LL_LPTIM_GetAutoReload(LPTIM) + 1;
lp_time += z_clock_lptim_getcounter();
break;
}
lp_time = z_clock_lptim_getcounter();
/* Check if the flag ARRM wasn't be set during the process */
} while (arrm_state_get());
return lp_time;
}
uint32_t sys_clock_elapsed(void)
{
if (!IS_ENABLED(CONFIG_TICKLESS_KERNEL)) {
@ -246,20 +272,7 @@ uint32_t sys_clock_elapsed(void)
k_spinlock_key_t key = k_spin_lock(&lock);
uint32_t lp_time = 0;
/* In case of counter roll-over, add the autoreload value,
* even if the irq has not yet been handled.
* Check ARRM flag before loading counter to make
* sure we don't use a counter close to ARR that
* hasn't triggered ARRM yet, which would mistakenly
* account for double the number of ticks.
*/
if ((LL_LPTIM_IsActiveFlag_ARRM(LPTIM) != 0)
&& LL_LPTIM_IsEnabledIT_ARRM(LPTIM) != 0) {
lp_time += LL_LPTIM_GetAutoReload(LPTIM) + 1;
}
lp_time += z_clock_lptim_getcounter();
uint32_t lp_time = sys_clock_lp_time_get();
k_spin_unlock(&lock, key);
@ -277,15 +290,7 @@ uint32_t sys_clock_cycle_get_32(void)
k_spinlock_key_t key = k_spin_lock(&lock);
uint32_t lp_time = z_clock_lptim_getcounter();
/* In case of counter roll-over, add this value,
* even if the irq has not yet been handled
*/
if ((LL_LPTIM_IsActiveFlag_ARRM(LPTIM) != 0)
&& LL_LPTIM_IsEnabledIT_ARRM(LPTIM) != 0) {
lp_time += LL_LPTIM_GetAutoReload(LPTIM) + 1;
}
uint32_t lp_time = sys_clock_lp_time_get();
lp_time += accumulated_lptim_cnt;