[MPC512x] Proper handling of larger frames in the FEC driver

When frame larger than local RX buffer is received, it is split and handled
by two buffer descriptors. Prior to this patch the FEC driver discarded
contents of a buffer descriptor without the 'LAST' bit set, so the first
part of the frame was lost in case of larger frames. This fix allows to
safely combine the two pieces into the whole frame.

Signed-off-by: Grzegorz Bernacki <gjb@semihalf.com>

cpu/mpc512x/fec.c

@@ -32,6 +32,9 @@ int fec512x_miiphy_read(char *devname, uint8 phyAddr, uint8 regAddr, uint16 * re
 int fec512x_miiphy_write(char *devname, uint8 phyAddr, uint8 regAddr, uint16 data);
 int mpc512x_fec_init_phy(struct eth_device *dev, bd_t * bis);
 
+static uchar rx_buff[FEC_MAX_PKT_SIZE];
+static int rx_buff_idx = 0;
+
 /********************************************************************/
 #if (DEBUG & 0x2)
 static void mpc512x_fec_phydump (char *devname)
@@ -235,7 +238,7 @@ static int mpc512x_fec_init (struct eth_device *dev, bd_t * bis)
 	fec->eth->op_pause = 0x00010020;
 
 	/* Frame length=1518; MII mode */
-	fec->eth->r_cntrl = 0x05ee000c;
+	fec->eth->r_cntrl = 0x05ee0024;
 
 	/* Half-duplex, heartbeat disabled */
 	fec->eth->x_cntrl = 0x00000000;
@@ -520,8 +523,7 @@ static int mpc512x_fec_recv (struct eth_device *dev)
 	mpc512x_fec_priv *fec = (mpc512x_fec_priv *)dev->priv;
 	volatile FEC_RBD *pRbd = &fec->bdBase->rbd[fec->rbdIndex];
 	unsigned long ievent;
-	int frame_length, len = 0;
-	uchar buff[FEC_MAX_PKT_SIZE];
+	int frame_length = 0;
 
 #if (DEBUG & 0x1)
 	printf ("mpc512x_fec_recv %d Start...\n", fec->rbdIndex);
@@ -555,31 +557,37 @@ static int mpc512x_fec_recv (struct eth_device *dev)
 	}
 
 	if (!(pRbd->status & FEC_RBD_EMPTY)) {
-		if ((pRbd->status & FEC_RBD_LAST) &&
-			!(pRbd->status & FEC_RBD_ERR) &&
+		if (!(pRbd->status & FEC_RBD_ERR) &&
 			((pRbd->dataLength - 4) > 14)) {
 
 			/*
 			 * Get buffer size
 			 */
-			frame_length = pRbd->dataLength - 4;
-
+			if (pRbd->status & FEC_RBD_LAST)
+				frame_length = pRbd->dataLength - 4;
+			else
+				frame_length = pRbd->dataLength;
 #if (DEBUG & 0x20)
 			{
 				int i;
-				printf ("recv data hdr:");
+				printf ("recv data length 0x%08x data hdr: ",
+					pRbd->dataLength);
 				for (i = 0; i < 14; i++)
 					printf ("%x ", *((uint8*)pRbd->dataPointer + i));
 				printf("\n");
 			}
 #endif
-
 			/*
 			 *  Fill the buffer and pass it to upper layers
 			 */
-			memcpy (buff, (void*)pRbd->dataPointer, frame_length);
-			NetReceive ((uchar*)buff, frame_length);
-			len = frame_length;
+			memcpy (&rx_buff[rx_buff_idx], (void*)pRbd->dataPointer,
+				frame_length - rx_buff_idx);
+			rx_buff_idx = frame_length;
+
+			if (pRbd->status & FEC_RBD_LAST) {
+				NetReceive ((uchar*)rx_buff, frame_length);
+				rx_buff_idx = 0;
+			}
 		}
 
 		/*
@@ -590,7 +598,7 @@ static int mpc512x_fec_recv (struct eth_device *dev)
 
 	/* Try to fill Buffer Descriptors */
 	fec->eth->r_des_active = 0x01000000;	/* Descriptor polling active */
-	return len;
+	return frame_length;
 }
 
 /********************************************************************/