[bsp] [stm32] fix drv_can.c and can.c bug

bsp/stm32/libraries/HAL_Drivers/drv_can.c

@@ -515,7 +515,11 @@ static int _can_recvmsg(struct rt_can_device *can, void *buf, rt_uint32_t fifo)
     /* get len */
     pmsg->len = rxheader.DLC;
     /* get hdr */
+#ifdef BSP_USING_CAN2
     pmsg->hdr = rxheader.FilterMatchIndex;
+#else
+    pmsg->hdr = (rxheader.FilterMatchIndex + 1) >> 1;
+#endif
 
     return RT_EOK;
 }

components/drivers/can/can.c

@@ -853,8 +853,11 @@ void rt_hw_can_isr(struct rt_can_device *can, int event)
             level = rt_hw_interrupt_disable();
             rx_length = can->hdr[hdr].msgs * sizeof(struct rt_can_msg);
             rt_hw_interrupt_enable(level);
+            if (rx_length)
+            {
                 can->hdr[hdr].filter.ind(&can->parent, can->hdr[hdr].filter.args, hdr, rx_length);
             }
+        }
         else
 #endif
         {
@@ -867,9 +870,12 @@ void rt_hw_can_isr(struct rt_can_device *can, int event)
                 rx_length = rt_list_len(&rx_fifo->uselist)* sizeof(struct rt_can_msg);
                 rt_hw_interrupt_enable(level);
 
+                if (rx_length)
+                {
                     can->parent.rx_indicate(&can->parent, rx_length);
                 }
             }
+        }
         break;
     }