dpaa_eth: fix the RX headroom size alignment

The headroom reserved for received frames needs to be aligned to an
RX specific value. There is currently a discrepancy between the values
used in the Ethernet driver and the values passed to the FMan.
Coincidentally, the resulting aligned values are identical.

Fixes: 3c68b8ff ("dpaa_eth: FMan erratum A050385 workaround")
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Camelia Groza <camelia.groza@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/freescale/dpaa/dpaa_eth.c

@@ -2845,7 +2845,8 @@ static int dpaa_ingress_cgr_init(struct dpaa_priv *priv)
 	return err;
 }
 
-static inline u16 dpaa_get_headroom(struct dpaa_buffer_layout *bl)
+static u16 dpaa_get_headroom(struct dpaa_buffer_layout *bl,
+			     enum port_type port)
 {
 	u16 headroom;
 
@@ -2859,8 +2860,11 @@ static inline u16 dpaa_get_headroom(struct dpaa_buffer_layout *bl)
 	 *
 	 * Also make sure the headroom is a multiple of data_align bytes
 	 */
-	headroom = (u16)(bl->priv_data_size + DPAA_HWA_SIZE);
+	headroom = (u16)(bl[port].priv_data_size + DPAA_HWA_SIZE);
 
+	if (port == RX)
+		return ALIGN(headroom, DPAA_FD_RX_DATA_ALIGNMENT);
+	else
 		return ALIGN(headroom, DPAA_FD_DATA_ALIGNMENT);
 }
 
@@ -3029,8 +3033,8 @@ static int dpaa_eth_probe(struct platform_device *pdev)
 			goto free_dpaa_fqs;
 	}
 
-	priv->tx_headroom = dpaa_get_headroom(&priv->buf_layout[TX]);
-	priv->rx_headroom = dpaa_get_headroom(&priv->buf_layout[RX]);
+	priv->tx_headroom = dpaa_get_headroom(priv->buf_layout, TX);
+	priv->rx_headroom = dpaa_get_headroom(priv->buf_layout, RX);
 
 	/* All real interfaces need their ports initialized */
 	err = dpaa_eth_init_ports(mac_dev, dpaa_bp, &port_fqs,