mv643xx_eth: enable hardware TX checksumming with vlan tags
Although mv643xx_eth has no hardware support for inserting a vlan
tag by twiddling some bits in the TX descriptor, it does support
hardware TX checksumming on packets where the IP header starts {a
limited set of values other than 14} bytes into the packet.
This patch sets mv643xx_eth's ->vlan_features to NETIF_F_SG |
NETIF_F_IP_CSUM, which prevents the stack from checksumming vlan'ed
packets in software, and if vlan tags are present on a transmitted
packet, notifies the hardware of this fact by toggling the right
bits in the TX descriptor.
Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>
diff --git a/drivers/net/mv643xx_eth.c b/drivers/net/mv643xx_eth.c
index 01dd3c5..88bb1f1 100644
--- a/drivers/net/mv643xx_eth.c
+++ b/drivers/net/mv643xx_eth.c
@@ -235,6 +235,8 @@
#define GEN_IP_V4_CHECKSUM 0x00040000
#define GEN_TCP_UDP_CHECKSUM 0x00020000
#define UDP_FRAME 0x00010000
+#define MAC_HDR_EXTRA_4_BYTES 0x00008000
+#define MAC_HDR_EXTRA_8_BYTES 0x00000200
#define TX_IHL_SHIFT 11
@@ -757,12 +759,36 @@
desc->buf_ptr = dma_map_single(NULL, skb->data, length, DMA_TO_DEVICE);
if (skb->ip_summed == CHECKSUM_PARTIAL) {
- BUG_ON(skb->protocol != htons(ETH_P_IP));
+ int mac_hdr_len;
+
+ BUG_ON(skb->protocol != htons(ETH_P_IP) &&
+ skb->protocol != htons(ETH_P_8021Q));
cmd_sts |= GEN_TCP_UDP_CHECKSUM |
GEN_IP_V4_CHECKSUM |
ip_hdr(skb)->ihl << TX_IHL_SHIFT;
+ mac_hdr_len = (void *)ip_hdr(skb) - (void *)skb->data;
+ switch (mac_hdr_len - ETH_HLEN) {
+ case 0:
+ break;
+ case 4:
+ cmd_sts |= MAC_HDR_EXTRA_4_BYTES;
+ break;
+ case 8:
+ cmd_sts |= MAC_HDR_EXTRA_8_BYTES;
+ break;
+ case 12:
+ cmd_sts |= MAC_HDR_EXTRA_4_BYTES;
+ cmd_sts |= MAC_HDR_EXTRA_8_BYTES;
+ break;
+ default:
+ if (net_ratelimit())
+ dev_printk(KERN_ERR, &txq_to_mp(txq)->dev->dev,
+ "mac header length is %d?!\n", mac_hdr_len);
+ break;
+ }
+
switch (ip_hdr(skb)->protocol) {
case IPPROTO_UDP:
cmd_sts |= UDP_FRAME;
@@ -2565,6 +2591,7 @@
* have to map the buffers to ISA memory which is only 16 MB
*/
dev->features = NETIF_F_SG | NETIF_F_IP_CSUM;
+ dev->vlan_features = NETIF_F_SG | NETIF_F_IP_CSUM;
#endif
SET_NETDEV_DEV(dev, &pdev->dev);