Introduce new eth_receive routine

The purpose of this routine is receiving a single network frame, outside of
U-Boot's NetLoop(). Exporting it to standalone programs that run on top of
U-Boot will let them utilise networking facilities. For sending a raw frame
the already existing eth_send() can be used.

The direct consumer of this routine is the newly introduced API layer for
external applications (enabled with CONFIG_API).

Signed-off-by: Rafal Jaworowski <raj@semihalf.com>
Signed-off-by: Piotr Kruszynski <ppk@semihalf.com>
Signed-off-by: Ben Warren <biggerbadderben@gmail.com>

include/net.h

@@ -122,6 +122,9 @@ extern void eth_set_enetaddr(int num, char* a);	/* Set new MAC address		*/
 
 extern int eth_init(bd_t *bis);			/* Initialize the device	*/
 extern int eth_send(volatile void *packet, int length);	   /* Send a packet	*/
+#ifdef CONFIG_API
+extern int eth_receive(volatile void *packet, int length); /* Receive a packet	*/
+#endif
 extern int eth_rx(void);			/* Check for received packets	*/
 extern void eth_halt(void);			/* stop SCC			*/
 extern char *eth_get_name(void);		/* get name of current device	*/

net/eth.c

@@ -62,6 +62,17 @@ extern int bfin_EMAC_initialize(bd_t *);
 extern int atstk1000_eth_initialize(bd_t *);
 extern int mcffec_initialize(bd_t*);
 
+#ifdef CONFIG_API
+extern void (*push_packet)(volatile void *, int);
+
+static struct {
+	uchar data[PKTSIZE];
+	int length;
+} eth_rcv_bufs[PKTBUFSRX];
+
+static unsigned int eth_rcv_current = 0, eth_rcv_last = 0;
+#endif
+
 static struct eth_device *eth_devices, *eth_current;
 
 struct eth_device *eth_get_dev(void)
@@ -457,6 +468,53 @@ int eth_rx(void)
 	return eth_current->recv(eth_current);
 }
 
+#ifdef CONFIG_API
+static void eth_save_packet(volatile void *packet, int length)
+{
+	volatile char *p = packet;
+	int i;
+
+	if ((eth_rcv_last+1) % PKTBUFSRX == eth_rcv_current)
+		return;
+
+	if (PKTSIZE < length)
+		return;
+
+	for (i = 0; i < length; i++)
+		eth_rcv_bufs[eth_rcv_last].data[i] = p[i];
+
+	eth_rcv_bufs[eth_rcv_last].length = length;
+	eth_rcv_last = (eth_rcv_last + 1) % PKTBUFSRX;
+}
+
+int eth_receive(volatile void *packet, int length)
+{
+	volatile char *p = packet;
+	void *pp = push_packet;
+	int i;
+
+	if (eth_rcv_current == eth_rcv_last) {
+		push_packet = eth_save_packet;
+		eth_rx();
+		push_packet = pp;
+
+		if (eth_rcv_current == eth_rcv_last)
+			return -1;
+	}
+
+	if (length < eth_rcv_bufs[eth_rcv_current].length)
+		return -1;
+
+	length = eth_rcv_bufs[eth_rcv_current].length;
+
+	for (i = 0; i < length; i++)
+		p[i] = eth_rcv_bufs[eth_rcv_current].data[i];
+
+	eth_rcv_current = (eth_rcv_current + 1) % PKTBUFSRX;
+	return length;
+}
+#endif /* CONFIG_API */
+
 void eth_try_another(int first_restart)
 {
 	static struct eth_device *first_failed = NULL;

net/net.c

@@ -137,6 +137,9 @@ uchar		NetBcastAddr[6] =	/* Ethernet bcast address		*/
 			{ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 uchar		NetEtherNullAddr[6] =
 			{ 0, 0, 0, 0, 0, 0 };
+#ifdef CONFIG_API
+void		(*push_packet)(volatile void *, int len) = 0;
+#endif
 #if defined(CONFIG_CMD_CDP)
 uchar		NetCDPAddr[6] =		/* Ethernet bcast address		*/
 			{ 0x01, 0x00, 0x0c, 0xcc, 0xcc, 0xcc };
@@ -1161,6 +1164,13 @@ NetReceive(volatile uchar * inpkt, int len)
 	if (len < ETHER_HDR_SIZE)
 		return;
 
+#ifdef CONFIG_API
+	if (push_packet) {
+		(*push_packet)(inpkt, len);
+		return;
+	}
+#endif
+
 #if defined(CONFIG_CMD_CDP)
 	/* keep track if packet is CDP */
 	iscdp = memcmp(et->et_dest, NetCDPAddr, 6) == 0;