mv643xx_eth: use sw csum for big packets

Some controllers (KW, Dove) limits the TX IP/layer4 checksum offloading to a max size.

Signed-off-by: Saeed Bishara <saeed@marvell.com>
Acked-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/mv643xx_eth.h b/include/linux/mv643xx_eth.h
index cbbbe9b..30b0c4e 100644
--- a/include/linux/mv643xx_eth.h
+++ b/include/linux/mv643xx_eth.h
@@ -19,6 +19,11 @@
 	struct mbus_dram_target_info	*dram;
 	struct platform_device	*shared_smi;
 	unsigned int		t_clk;
+	/*
+	 * Max packet size for Tx IP/Layer 4 checksum, when set to 0, default
+	 * limit of 9KiB will be used.
+	 */
+	int			tx_csum_limit;
 };
 
 #define MV643XX_ETH_PHY_ADDR_DEFAULT	0