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drivers: timer: stm32 lptim fix long time interrupt locking

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The waiting of the flag ARROK could be quite long (100µs-200µs in my
test). During this time, the interrupts are locked that is not
recommended. To avoid this, we manage the update of the autoreload value
in interruption

Signed-off-by: Julien D'Ascenzio <julien.dascenzio@paratronic.fr>
This commit is contained in:
Julien D'Ascenzio 2022-06-23 11:37:48 +02:00 • committed by Carles Cufí
commit a703cbe9ce
1 changed files with 41 additions and 12 deletions
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53
drivers/timer/stm32_lptim_timer.c
View file

@ -43,6 +43,10 @@
* This is for example about of 65000 x 2000ms when clocked by LSI
*/
static uint32_t accumulated_lptim_cnt;
/* Next autoreload value to set */
static uint32_t autoreload_next;
/* Indicate if the autoreload register is ready for a write */
static bool autoreload_ready = true;
static struct k_spinlock lock;
@ -51,6 +55,20 @@ static void lptim_irq_handler(const struct device *unused)
ARG_UNUSED(unused);
uint32_t autoreload = LL_LPTIM_GetAutoReload(LPTIM1);
if ((LL_LPTIM_IsActiveFlag_ARROK(LPTIM1) != 0)
&& LL_LPTIM_IsEnabledIT_ARROK(LPTIM1) != 0) {
LL_LPTIM_ClearFlag_ARROK(LPTIM1);
if ((autoreload_next > 0) && (autoreload_next != autoreload)) {
/* the new autoreload value change, we set it */
autoreload_ready = false;
LL_LPTIM_SetAutoReload(LPTIM1, autoreload_next);
} else {
autoreload_ready = true;
}
}
if ((LL_LPTIM_IsActiveFlag_ARRM(LPTIM1) != 0)
&& LL_LPTIM_IsEnabledIT_ARRM(LPTIM1) != 0) {
@ -61,9 +79,8 @@ static void lptim_irq_handler(const struct device *unused)
/* increase the total nb of autoreload count
* used in the sys_clock_cycle_get_32() function.
* Reading the CNT register gives a reliable value
*/
uint32_t autoreload = LL_LPTIM_GetAutoReload(LPTIM1) + 1;
autoreload++;
accumulated_lptim_cnt += autoreload;
@ -79,6 +96,23 @@ static void lptim_irq_handler(const struct device *unused)
}
}
static void lptim_set_autoreload(uint32_t arr)
{
/* Update autoreload register */
autoreload_next = arr;
if (!autoreload_ready)
return;
/* The ARR register ready, we could set it directly */
if ((arr > 0) && (arr != LL_LPTIM_GetAutoReload(LPTIM1))) {
/* The new autoreload value change, we set it */
autoreload_ready = false;
LL_LPTIM_ClearFlag_ARROK(LPTIM1);
LL_LPTIM_SetAutoReload(LPTIM1, arr);
}
}
static inline uint32_t z_clock_lptim_getcounter(void)
{
uint32_t lp_time;
@ -175,13 +209,8 @@ void sys_clock_set_timeout(int32_t ticks, bool idle)
next_arr = lp_time + LPTIM_GUARD_VALUE;
}
/* ARROK bit validates previous write operation to ARR register */
while (LL_LPTIM_IsActiveFlag_ARROK(LPTIM1) == 0) {
}
LL_LPTIM_ClearFlag_ARROK(LPTIM1);
/* run timer and wait for the reload match */
LL_LPTIM_SetAutoReload(LPTIM1, next_arr);
/* Update autoreload register */
lptim_set_autoreload(next_arr);
k_spin_unlock(&lock, key);
}
@ -345,6 +374,7 @@ static int sys_clock_driver_init(const struct device *dev)
#endif
LL_LPTIM_ClearFLAG_ARRM(LPTIM1);
/* ARROK bit validates the write operation to ARR register */
LL_LPTIM_EnableIT_ARROK(LPTIM1);
LL_LPTIM_ClearFlag_ARROK(LPTIM1);
accumulated_lptim_cnt = 0;
@ -357,11 +387,10 @@ static int sys_clock_driver_init(const struct device *dev)
/* Set the Autoreload value once the timer is enabled */
if (IS_ENABLED(CONFIG_TICKLESS_KERNEL)) {
/* LPTIM1 is triggered on a LPTIM_TIMEBASE period */
LL_LPTIM_SetAutoReload(LPTIM1, LPTIM_TIMEBASE);
lptim_set_autoreload(LPTIM_TIMEBASE);
} else {
/* LPTIM1 is triggered on a Tick period */
LL_LPTIM_SetAutoReload(LPTIM1, COUNT_PER_TICK - 1);
lptim_set_autoreload(COUNT_PER_TICK - 1);
}
/* Start the LPTIM counter in continuous mode */