altera_tse: Correct rx packet length

Altera TSE MAC rx DMA transfer starts with the 2 additional bytes for IP
payload alignment. This patch fixes tse_rx() function loop which reads DMA
rx status and extracts packet length from it. Status signalises a whole DMA
transfer length, which is 2 bytes longer than the packet itself.

Signed-off-by: Vlastimil Setka <setka@vsis.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/net/ethernet/altera/altera_tse_main.c b/drivers/net/ethernet/altera/altera_tse_main.c
index 0533c051a3e5..da48e66377b5 100644
--- a/drivers/net/ethernet/altera/altera_tse_main.c
+++ b/drivers/net/ethernet/altera/altera_tse_main.c
@@ -391,6 +391,12 @@ static int tse_rx(struct altera_tse_private *priv, int limit)
                                    "RCV pktstatus %08X pktlength %08X\n",
                                    pktstatus, pktlength);
 
+                /* DMA trasfer from TSE starts with 2 aditional bytes for
+                 * IP payload alignment. Status returned by get_rx_status()
+                 * contains DMA transfer length. Packet is 2 bytes shorter.
+                 */
+                pktlength -= 2;
+
                 count++;
                 next_entry = (++priv->rx_cons) % priv->rx_ring_size;