esp_timer: Fix System time jumps back ~54secs

Closes: https://github.com/espressif/esp-idf/issues/2513

components/esp32/esp_timer_esp32.c

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#include "sys/param.h"
 #include "esp_err.h"
 #include "esp_timer.h"
 #include "esp_system.h"
@@ -127,13 +128,6 @@ static uint32_t s_timer_us_per_overflow;
 // will not increment s_time_base_us if this flag is set.
 static bool s_mask_overflow;
 
-//The timer_overflow_happened read alarm register to tell if overflow happened.
-//However, there is a monent that overflow happens, and before ISR function called
-//alarm register is set to another value, then you call timer_overflow_happened,
-//it will return false.
-//So we store the overflow value when new alarm is to be set.
-static bool s_overflow_happened;
-
 #ifdef CONFIG_PM_DFS_USE_RTC_TIMER_REF
 // If DFS is enabled, upon the first frequency change this value is set to the
 // difference between esp_timer value and RTC timer value. On every subsequent
@@ -152,10 +146,6 @@ portMUX_TYPE s_time_update_lock = portMUX_INITIALIZER_UNLOCKED;
 // Check if timer overflow has happened (but was not handled by ISR yet)
 static inline bool IRAM_ATTR timer_overflow_happened()
 {
-    if (s_overflow_happened) {
-        return true;
-    }
-
     return ((REG_READ(FRC_TIMER_CTRL_REG(1)) & FRC_TIMER_INT_STATUS) != 0 &&
               ((REG_READ(FRC_TIMER_ALARM_REG(1)) == ALARM_OVERFLOW_VAL && TIMER_IS_AFTER_OVERFLOW(REG_READ(FRC_TIMER_COUNT_REG(1))) && !s_mask_overflow) ||
                (!TIMER_IS_AFTER_OVERFLOW(REG_READ(FRC_TIMER_ALARM_REG(1))) && TIMER_IS_AFTER_OVERFLOW(REG_READ(FRC_TIMER_COUNT_REG(1))))));
@@ -222,35 +212,31 @@ uint64_t IRAM_ATTR esp_timer_impl_get_time()
 void IRAM_ATTR esp_timer_impl_set_alarm(uint64_t timestamp)
 {
     portENTER_CRITICAL(&s_time_update_lock);
-    // Alarm time relative to the moment when counter was 0
-    uint64_t time_after_timebase_us = timestamp - s_time_base_us;
-    // Adjust current time if overflow has happened
-    bool overflow = timer_overflow_happened();
-    uint64_t cur_count = REG_READ(FRC_TIMER_COUNT_REG(1));
-
-    if (overflow) {
-        assert(time_after_timebase_us > s_timer_us_per_overflow);
-        time_after_timebase_us -= s_timer_us_per_overflow;
-        s_overflow_happened = true;
-    }
-    // Calculate desired timer compare value (may exceed 2^32-1)
-    uint64_t compare_val = time_after_timebase_us * s_timer_ticks_per_us;
-    uint32_t alarm_reg_val = ALARM_OVERFLOW_VAL;
     // Use calculated alarm value if it is less than ALARM_OVERFLOW_VAL.
     // Note that if by the time we update ALARM_REG, COUNT_REG value is higher,
     // interrupt will not happen for another ALARM_OVERFLOW_VAL timer ticks,
     // so need to check if alarm value is too close in the future (e.g. <2 us away).
     const uint32_t offset = s_timer_ticks_per_us * 2;
+    do {
+        // Adjust current time if overflow has happened
+        if (timer_overflow_happened()) {
+            timer_count_reload();
+            s_time_base_us += s_timer_us_per_overflow;
+        }
+        s_mask_overflow = false;
+        uint64_t cur_count = REG_READ(FRC_TIMER_COUNT_REG(1));
+        // Alarm time relative to the moment when counter was 0
+        int64_t time_after_timebase_us = (int64_t)timestamp - s_time_base_us;
+        // Calculate desired timer compare value (may exceed 2^32-1)
+        int64_t compare_val = time_after_timebase_us * s_timer_ticks_per_us;
+
+        compare_val = MAX(compare_val, cur_count + offset);
+        uint32_t alarm_reg_val = ALARM_OVERFLOW_VAL;
         if (compare_val < ALARM_OVERFLOW_VAL) {
-        if (compare_val < cur_count + offset) {
-            compare_val = cur_count + offset;
-            if (compare_val > ALARM_OVERFLOW_VAL) {
-                compare_val = ALARM_OVERFLOW_VAL;
-            }
-        }
             alarm_reg_val = (uint32_t) compare_val;
         }
         REG_WRITE(FRC_TIMER_ALARM_REG(1), alarm_reg_val);
+    } while (REG_READ(FRC_TIMER_ALARM_REG(1)) <= REG_READ(FRC_TIMER_COUNT_REG(1)));
     portEXIT_CRITICAL(&s_time_update_lock);
 }
 
@@ -261,7 +247,6 @@ static void IRAM_ATTR timer_alarm_isr(void *arg)
     if (timer_overflow_happened()) {
         timer_count_reload();
         s_time_base_us += s_timer_us_per_overflow;
-        s_overflow_happened = false;
     }
     s_mask_overflow = false;
     // Clear interrupt status
@@ -336,7 +321,6 @@ void esp_timer_impl_advance(int64_t time_us)
     REG_WRITE(FRC_TIMER_ALARM_REG(1), 0);
     REG_WRITE(FRC_TIMER_LOAD_REG(1), 0);
     s_time_base_us += count / s_timer_ticks_per_us + time_us;
-    s_overflow_happened = false;
     portEXIT_CRITICAL(&s_time_update_lock);
 }
 

components/esp_common/src/esp_timer.c

@@ -126,12 +126,15 @@ esp_err_t IRAM_ATTR esp_timer_start_once(esp_timer_handle_t timer, uint64_t time
     if (!is_initialized() || timer_armed(timer)) {
         return ESP_ERR_INVALID_STATE;
     }
+    timer_list_lock();
     timer->alarm = esp_timer_get_time() + timeout_us;
     timer->period = 0;
 #if WITH_PROFILING
     timer->times_armed++;
 #endif
-    return timer_insert(timer);
+    esp_err_t err = timer_insert(timer);
+    timer_list_unlock();
+    return err;
 }
 
 esp_err_t IRAM_ATTR esp_timer_start_periodic(esp_timer_handle_t timer, uint64_t period_us)
@@ -139,13 +142,16 @@ esp_err_t IRAM_ATTR esp_timer_start_periodic(esp_timer_handle_t timer, uint64_t
     if (!is_initialized() || timer_armed(timer)) {
         return ESP_ERR_INVALID_STATE;
     }
+    timer_list_lock();
     period_us = MAX(period_us, esp_timer_impl_get_min_period_us());
     timer->alarm = esp_timer_get_time() + period_us;
     timer->period = period_us;
 #if WITH_PROFILING
     timer->times_armed++;
 #endif
-    return timer_insert(timer);
+    esp_err_t err = timer_insert(timer);
+    timer_list_unlock();
+    return err;
 }
 
 esp_err_t IRAM_ATTR esp_timer_stop(esp_timer_handle_t timer)
@@ -164,16 +170,17 @@ esp_err_t esp_timer_delete(esp_timer_handle_t timer)
     if (timer_armed(timer)) {
         return ESP_ERR_INVALID_STATE;
     }
+    timer_list_lock();
     timer->event_id = EVENT_ID_DELETE_TIMER;
-    timer->alarm = esp_timer_get_time() + 50;
+    timer->alarm = esp_timer_get_time();
     timer->period = 0;
     timer_insert(timer);
+    timer_list_unlock();
     return ESP_OK;
 }
 
 static IRAM_ATTR esp_err_t timer_insert(esp_timer_handle_t timer)
 {
-    timer_list_lock();
 #if WITH_PROFILING
     timer_remove_inactive(timer);
 #endif
@@ -196,7 +203,6 @@ static IRAM_ATTR esp_err_t timer_insert(esp_timer_handle_t timer)
     if (timer == LIST_FIRST(&s_timers)) {
         esp_timer_impl_set_alarm(timer->alarm);
     }
-    timer_list_unlock();
     return ESP_OK;
 }