nic: Fix incorrect wrap handling of RX circular buffer

nic: move other nic functions into the dedicated nic files
uip: alloc buffer multiple of 8 bytes

Signed-off-by: João Silva <jgc3silva@gmail.com>

uip/uip-conf.h

@@ -132,6 +132,10 @@ typedef unsigned short uip_stats_t;
  */
 #define UIP_CONF_BUFFER_SIZE     1556
 
+/* Backing storage includes padding for the NIC's eight-byte DMA transfers.
+ * Keep UIP_CONF_BUFFER_SIZE as the logical frame/MSS limit. */
+#define UIP_CONF_BUFFER_ALLOC_SIZE ((UIP_CONF_BUFFER_SIZE + 7U) & ~7U)
+
 /**
  * Bytes of the buffer kept out of the advertised MSS.
  *

uip/uip.c

@@ -136,7 +136,7 @@ static __code const uip_ipaddr_t all_zeroes_addr =
 #endif /* UIP_CONF_IPV6 */
 
 #ifndef UIP_CONF_EXTERNAL_BUFFER
-u8_t uip_buf[UIP_BUFSIZE + 2];   /* The packet buffer that contains
+u8_t uip_buf[UIP_CONF_BUFFER_ALLOC_SIZE];   /* The packet buffer that contains
 				    incoming packets. */
 #endif /* UIP_CONF_EXTERNAL_BUFFER */
 

uip/uipopt.h

@@ -419,7 +419,7 @@
 #endif /* UIP_CONF_BUFFER_EXTRA */
 
 
-extern __xdata uint8_t uip_buf[UIP_CONF_BUFFER_SIZE+2];
+extern __xdata uint8_t uip_buf[UIP_CONF_BUFFER_ALLOC_SIZE];
 
 /**
  * Determines if statistics support should be compiled in.