drivers: timer: nrf: Fix expected_sys_ticks issue in case of k_busy_wait
In case of tickless kernel, k_busy_wait() calls __enable_sys_clock()
which in turn calls _set_time() with maximum RTC counter programmable
value. This will set the expected_sys_ticks to maximum tick value even
though there is no explicit timeout is requested from the kernel or from
an application. In this scenario, if an app calls k_sleep() which in
turn calls _add_timeout() which will adjust timeout value as per the
elapsed program time which based on incorrectly set expected_sys_ticks.
To fix this issue, we should not set the expected_sys_ticks in case
of __enable_sys_clock() as it just requests to run the counter but
a timeout event request.
Signed-off-by: Ramakrishna Pallala <ramakrishna.pallala@intel.com>
diff --git a/drivers/timer/nrf_rtc_timer.c b/drivers/timer/nrf_rtc_timer.c
index 677a454..7415093 100644
--- a/drivers/timer/nrf_rtc_timer.c
+++ b/drivers/timer/nrf_rtc_timer.c
@@ -211,6 +211,25 @@
#ifdef CONFIG_TICKLESS_KERNEL
+/*
+ * Set RTC Counter Compare (CC) register to max value
+ * and update the _sys_clock_tick_count.
+ */
+static inline void program_max_cycles(void)
+{
+ u32_t max_cycles = _get_max_clock_time();
+
+ _sys_clock_tick_count = _get_elapsed_clock_time();
+ /* Update rtc_past to track rtc timer count*/
+ rtc_past = (_sys_clock_tick_count *
+ sys_clock_hw_cycles_per_tick) & RTC_MASK;
+
+ /* Programe RTC compare register to generate interrupt*/
+ rtc_compare_set(rtc_past +
+ (max_cycles * sys_clock_hw_cycles_per_tick));
+
+}
+
/**
* @brief provides total systicks programmed.
@@ -339,7 +358,7 @@
{
if (!expected_sys_ticks) {
/* Programe sys tick to Maximum possible value*/
- _set_time(_get_max_clock_time());
+ program_max_cycles();
}
}
@@ -462,6 +481,12 @@
#endif
#ifdef CONFIG_TICKLESS_KERNEL
+ if (!expected_sys_ticks) {
+ if (_sys_clock_always_on) {
+ program_max_cycles();
+ }
+ return;
+ }
_sys_idle_elapsed_ticks = expected_sys_ticks;
/* Initialize expected sys tick,
* It will be later updated based on next timeout.
@@ -469,6 +494,11 @@
expected_sys_ticks = 0;
/* Anounce elapsed of _sys_idle_elapsed_ticks systicks*/
_sys_clock_tick_announce();
+
+ /* _sys_clock_tick_announce() could cause new programming */
+ if (!expected_sys_ticks && _sys_clock_always_on) {
+ program_max_cycles();
+ }
#else
rtc_announce_set_next();
#endif
