+ * recv: Check if the hardware received a packet. If so, set the pointer to the
+ * packet buffer in the packetp parameter. If not, return an error or 0 to
+ * indicate that the hardware receive FIFO is empty. If 0 is returned, the
+ * network stack will not process the empty packet, but free_pkt() will be
+ * called if supplied
+ * free_pkt: Give the driver an opportunity to manage its packet buffer memory
+ * when the network stack is finished processing it. This will only be
+ * called when no error was returned from recv - optional