riscv/esp32c3: Fix RT timer issues

1. Enable alarm if there is timer active
2. Wake up main thread to delete timer
3. Wake up main thread when timer is timeout in ISR

arch/risc-v/src/esp32c3/esp32c3_rt_timer.c

@@ -253,6 +253,7 @@ static void stop_rt_timer(FAR struct rt_timer_s *timer)
 
 static void delete_rt_timer(FAR struct rt_timer_s *timer)
 {
+  int ret;
   irqstate_t flags;
 
   flags = enter_critical_section();
@@ -273,6 +274,14 @@ static void delete_rt_timer(FAR struct rt_timer_s *timer)
   list_add_after(&s_toutlist, &timer->list);
   timer->state = RT_TIMER_DELETE;
 
+  /* Wake up thread to process deleted timers */
+
+  ret = nxsem_post(&s_toutsem);
+  if (ret < 0)
+    {
+      tmrerr("ERROR: Failed to post sem ret=%d\n", ret);
+    }
+
 exit:
   leave_critical_section(flags);
 }
@@ -387,20 +396,18 @@ static int rt_timer_thread(int argc, FAR char *argv[])
 
 static int rt_timer_isr(int irq, void *context, void *arg)
 {
+  int ret;
   irqstate_t flags;
   struct rt_timer_s *timer;
   uint64_t alarm;
   uint64_t counter;
+  bool wake = false;
   struct esp32c3_tim_dev_s *tim = s_esp32c3_tim_dev;
 
   /* Clear interrupt register status */
 
   ESP32C3_TIM_ACKINT(tim);
 
-  /* Wake up thread to process timeout timers */
-
-  nxsem_post(&s_toutsem);
-
   flags = enter_critical_section();
 
   /* Check if there is timer running */
@@ -428,6 +435,7 @@ static int rt_timer_isr(int irq, void *context, void *arg)
           list_delete(&timer->list);
           timer->state = RT_TIMER_TIMEOUT;
           list_add_after(&s_toutlist, &timer->list);
+          wake = true;
 
           /* Check if thers is timer running */
 
@@ -439,9 +447,23 @@ static int rt_timer_isr(int irq, void *context, void *arg)
               alarm = timer->alarm;
 
               ESP32C3_TIM_SETALRVL(tim, alarm);
-              ESP32C3_TIM_SETALRM(tim, true);
             }
         }
+
+      /* If there is timer in list, alarm should be enable */
+
+      ESP32C3_TIM_SETALRM(tim, true);
+    }
+
+  if (wake)
+    {
+      /* Wake up thread to process timeout timers */
+
+      ret = nxsem_post(&s_toutsem);
+      if (ret < 0)
+        {
+          tmrerr("ERROR: Failed to post sem ret=%d\n", ret);
+        }
     }
 
   leave_critical_section(flags);