task_wdt: Fix the way the kernel timer is used
Do not use periodic executions of the timer handler, as in certain
circumstances (the fallback hardware watchdog used, one or more
task_wdt channel activated but none of them being ever fed) this
would lead to no callback/reset being executed for any channel.
Instead, schedule the next timeout from the timer handler function
when the function is executed for the dummy background channel or
for a channel that was deleted.
Signed-off-by: Andrzej Głąbek <andrzej.glabek@nordicsemi.no>
diff --git a/subsys/task_wdt/task_wdt.c b/subsys/task_wdt/task_wdt.c
index 24a6127..7121918 100644
--- a/subsys/task_wdt/task_wdt.c
+++ b/subsys/task_wdt/task_wdt.c
@@ -50,6 +50,40 @@
static bool hw_wdt_started;
#endif
+static void schedule_next_timeout(uint32_t current_ticks)
+{
+ int next_channel_id; /* channel which will time out next */
+ int64_t next_timeout; /* timeout in absolute ticks of this channel */
+
+#ifdef CONFIG_TASK_WDT_HW_FALLBACK
+ next_channel_id = TASK_WDT_BACKGROUND_CHANNEL;
+ next_timeout = current_ticks +
+ k_ms_to_ticks_ceil64(CONFIG_TASK_WDT_MIN_TIMEOUT);
+#else
+ next_channel_id = 0;
+ next_timeout = INT64_MAX;
+#endif
+
+ /* find minimum timeout of all channels */
+ for (int id = 0; id < ARRAY_SIZE(channels); id++) {
+ if (channels[id].reload_period != 0 &&
+ channels[id].timeout_abs_ticks < next_timeout) {
+ next_channel_id = id;
+ next_timeout = channels[id].timeout_abs_ticks;
+ }
+ }
+
+ /* update task wdt kernel timer */
+ k_timer_user_data_set(&timer, (void *)next_channel_id);
+ k_timer_start(&timer, K_TIMEOUT_ABS_TICKS(next_timeout), K_FOREVER);
+
+#ifdef CONFIG_TASK_WDT_HW_FALLBACK
+ if (hw_wdt_dev) {
+ wdt_feed(hw_wdt_dev, hw_wdt_channel);
+ }
+#endif
+}
+
/**
* @brief Task watchdog timer callback.
*
@@ -67,20 +101,20 @@
static void task_wdt_trigger(struct k_timer *timer_id)
{
int channel_id = (int)k_timer_user_data_get(timer_id);
+ bool bg_channel = IS_ENABLED(CONFIG_TASK_WDT_HW_FALLBACK) &&
+ (channel_id == TASK_WDT_BACKGROUND_CHANNEL);
-#ifdef CONFIG_TASK_WDT_HW_FALLBACK
- if (channel_id == TASK_WDT_BACKGROUND_CHANNEL) {
- if (hw_wdt_dev) {
- wdt_feed(hw_wdt_dev, hw_wdt_channel);
- }
+ /* If the timeout expired for the background channel (so the hardware
+ * watchdog needs to be fed) or for a channel that has been deleted,
+ * only schedule a new timeout (the hardware watchdog, if used, will be
+ * fed right after that new timeout is scheduled).
+ */
+ if (bg_channel || channels[channel_id].reload_period == 0) {
+ schedule_next_timeout(sys_clock_tick_get());
return;
}
-#endif
- if (channels[channel_id].reload_period == 0) {
- /* channel was deleted */
- return;
- } else if (channels[channel_id].callback) {
+ if (channels[channel_id].callback) {
channels[channel_id].callback(channel_id,
channels[channel_id].user_data);
} else {
@@ -157,8 +191,6 @@
int task_wdt_feed(int channel_id)
{
int64_t current_ticks;
- int next_channel_id; /* channel which will time out next */
- int64_t next_timeout; /* timeout in absolute ticks of this channel */
if (channel_id < 0 || channel_id >= ARRAY_SIZE(channels)) {
return -EINVAL;
@@ -178,34 +210,7 @@
channels[channel_id].timeout_abs_ticks = current_ticks +
k_ms_to_ticks_ceil64(channels[channel_id].reload_period);
-#ifdef CONFIG_TASK_WDT_HW_FALLBACK
- next_channel_id = TASK_WDT_BACKGROUND_CHANNEL;
- next_timeout = current_ticks +
- k_ms_to_ticks_ceil64(CONFIG_TASK_WDT_MIN_TIMEOUT);
-#else
- next_channel_id = 0;
- next_timeout = INT64_MAX;
-#endif
-
- /* find minimum timeout of all channels */
- for (int id = 0; id < ARRAY_SIZE(channels); id++) {
- if (channels[id].reload_period != 0 &&
- channels[id].timeout_abs_ticks < next_timeout) {
- next_channel_id = id;
- next_timeout = channels[id].timeout_abs_ticks;
- }
- }
-
- /* update task wdt kernel timer */
- k_timer_user_data_set(&timer, (void *)next_channel_id);
- k_timer_start(&timer, K_TIMEOUT_ABS_TICKS(next_timeout),
- K_TIMEOUT_ABS_TICKS(next_timeout));
-
-#ifdef CONFIG_TASK_WDT_HW_FALLBACK
- if (hw_wdt_dev) {
- wdt_feed(hw_wdt_dev, hw_wdt_channel);
- }
-#endif
+ schedule_next_timeout(current_ticks);
k_sched_unlock();
