fix(CAN): Avoid double counting RX overflow drops

Author: wdfk-prog

components/drivers/can/dev_can.c

@@ -968,15 +968,19 @@ rt_err_t rt_hw_can_register(struct rt_can_device    *can,
  */
 void rt_hw_can_isr(struct rt_can_device *can, int event)
 {
+    rt_bool_t is_rxof_event = RT_FALSE;
+
     switch (event & 0xff)
     {
     case RT_CAN_EVENT_RXOF_IND:
     {
         rt_base_t level;
+        is_rxof_event = RT_TRUE;
         level = rt_hw_local_irq_disable();
         can->status.dropedrcvpkg++;
         rt_hw_local_irq_enable(level);
     }
+    /* FALLTHROUGH: RX overflow still tries to fetch one pending frame into software FIFO. */
     case RT_CAN_EVENT_RX_IND:
     {
         struct rt_can_msg tmpmsg;
@@ -1020,7 +1024,10 @@ void rt_hw_can_isr(struct rt_can_device *can, int event)
         else if (!rt_list_isempty(&rx_fifo->uselist))
         {
             listmsg = rt_list_entry(rx_fifo->uselist.next, struct rt_can_msg_list, list);
-            can->status.dropedrcvpkg++;
+            if (!is_rxof_event)
+            {
+                can->status.dropedrcvpkg++;
+            }
             rt_list_remove(&listmsg->list);
 #ifdef RT_CAN_USING_HDR
             rt_list_remove(&listmsg->hdrlist);