ramips: Fix setting of rx buffer length

The length of the DMA rx buffer was always set to 0 because the function
for extracting the length was used to calculate the value for setting it.
Instead the macro has to be split in a get and set function similar to the
TX_DMA_(GET_|)PLEN(0|1) macro.

No problem was noticed on MT7621a before this was changed and thus maybe it
was hidden by different problem which is not yet fixed.

Signed-off-by: Sven Eckelmann <sven@open-mesh.com>

SVN-Revision: 47115

target/linux/ramips/files/drivers/net/ethernet/ralink/ralink_soc_eth.c

@@ -849,7 +849,7 @@ static int fe_poll_rx(struct napi_struct *napi, int budget,
 
 		dma_unmap_single(&netdev->dev, trxd.rxd1,
 				ring->rx_buf_size, DMA_FROM_DEVICE);
-		pktlen = RX_DMA_PLEN0(trxd.rxd2);
+		pktlen = RX_DMA_GET_PLEN0(trxd.rxd2);
 		skb->dev = netdev;
 		skb_put(skb, pktlen);
 		if (trxd.rxd4 & checksum_bit) {

target/linux/ramips/files/drivers/net/ethernet/ralink/ralink_soc_eth.h

@@ -310,7 +310,8 @@ enum fe_work_flag {
 /* rxd2 */
 #define RX_DMA_DONE		BIT(31)
 #define RX_DMA_LSO		BIT(30)
-#define RX_DMA_PLEN0(_x)	(((_x) >> 16) & 0x3fff)
+#define RX_DMA_PLEN0(_x)	(((_x) & 0x3fff) << 16)
+#define RX_DMA_GET_PLEN0(_x)	(((_x) >> 16) & 0x3fff)
 #define RX_DMA_TAG		BIT(15)
 /* rxd3 */
 #define RX_DMA_TPID(_x)		(((_x) >> 16) & 0xffff)